Government "HF communications" during the Great Patriotic War

P. N. Voronin

Government communications play an important role in the management of the state, its Armed Forces, and in socio-political and economic life. Its foundation was laid in 1918, when the Soviet Government moved to Moscow. Initially, a manual communication switch with 25 numbers was installed in Moscow, then it was expanded and subsequently replaced with a telephone exchange.

Long-distance government communications (called “HF communications” in memoirs and works of fiction) were organized in the 1930s as operational communications for state security agencies. It ensured a certain secrecy of negotiations, and therefore the heads of the highest government bodies and the Armed Forces also became its subscribers. In May 1941, by order of the Council of People's Commissars of the USSR, this connection was defined as “Governmental HF Communication” and the corresponding “Regulation” was approved. In accordance with the accepted terminology, “HF communications” can be classified as one of the secondary networks of the EASC and must meet additional requirements for the protection of transmitted information, reliability and survivability. However, it was not possible to fully implement these requirements before the start of the Great Patriotic War. As a means of controlling the Armed Forces in a combat situation, HF communications turned out to be unprepared.

The aggravation of the situation at the beginning of 1941 was felt by the increasing number of tasks for organizing HF communications for large formations and formations of the Red Army in the border zone. The night from June 21 to 22 found me performing one of these tasks. At approximately 4 o'clock in the morning, the technician on duty from Brest called and reported that the Germans had begun shelling the city. The evacuation has begun. What to do with the HF station equipment? Instructions were given to contact the local leadership and act on their instructions, but under all conditions to dismantle and remove the classified equipment. Then such calls came from Bialystok, Grodno and other cities along the western border. Thus began the war, which immediately posed a number of urgent tasks.

In view of the possible enemy bombing of Moscow, it was urgently necessary to move the Moscow HF station to a protected room. A room was allocated on the Kirovskaya metro platform. The station was closed to passengers. The installation was carried out in-house. The work was complicated by the fact that it was necessary to move the existing equipment without interrupting the operation of the HF station. We did not have backup equipment.

Similar work was carried out by the People's Commissariat (NK) of Communications. The telegraph equipment and intercity station were moved to protected premises. The work was headed by I. S. Ravich (at that time the head of the Central Directorate of Trunk Communications). We worked closely with him. The channels necessary for HF communication were to be received only from protected NK communication nodes.

The general unpreparedness of communications for war immediately had an impact. The entire network of the country was based on air lines, extremely susceptible to the influence of climatic conditions, and with the deployment of military operations and destruction by the enemy both through air bombing and sabotage groups. The Germans even used special bombs “with hooks” to destroy multi-wire communication lines. When falling, such a bomb caught on the wires with its hooks and exploded, destroying the entire bundle of wires at once.

There were also serious shortcomings in the construction of the long-distance communication network used. It was created according to a strictly radial principle. There were no ring communication lines or bypass directions, reserve communication centers protected from enemy bombing were not prepared, and even the entrances to Moscow of the main intercity routes were not ringed. If one of them was destroyed, it was impossible to switch the communication lines to another direction. NK Communications decided to urgently build in September 1941 a bypass ring communication line around Moscow along the Lyubertsy - Khimki - Pushkino - Chertanovo highway. In 1941, it was a ring located about 20 km from Moscow. NK Communications also carried out other work to improve the reliability of the long-distance network.

The task was set to provide HF communications with the fronts, and after the battle of Moscow - with the armies. A number of questions immediately arose and, first of all, who will build communication lines and operate them, how to provide front-line HF stations with communication equipment - compaction equipment, switches, batteries, classified communication equipment (ZAS) and other equipment adapted for work in field conditions .

The first issue was resolved quickly. The State Defense Committee (GKO) obliged the NK Communications and NK Defense to build and maintain Government Communications lines. But, as experience has shown, this was not The best decision. NK Communications had supervisors for servicing lines - one for tens of kilometers. With massive damage to air lines as a result of combat operations, air bombing and destruction by enemy sabotage groups, it was physically impossible to quickly repair the damage and ensure uninterrupted communications.

The NK defense signalmen were busy servicing the combat control lines and also could not focus their main attention on the Government communication lines. As a result, Government Communications worked unstably at some points, which led to justifiable complaints from subscribers. After each complaint, investigations began, clarification of the reasons, and mutual accusations began. Who is guilty? The matter reached the top leadership of the NKVD, NK Communications and NK Defense. A radical solution to this issue was needed.

In the Department of Government HF Communications of the NKVD, it was decided to create a line-operation service, for which purpose the formation of 10 line-operation companies, then another 35. Government communications began to work more steadily. But already during the battle of Moscow, when our troops began to advance and the headquarters of the fronts and armies moved forward, difficulties arose with the construction of communication lines.

This issue became especially acute in 1942, when the Germans approached the Volga and began to surround Stalingrad. I remember one autumn evening in 1942. The Germans were furiously rushing towards the city. The fighting took place at close approaches. The front headquarters was located in a shelter on the right bank of the Volga. Communication with the front was interrupted due to increased bombing of communication lines. Line units of the Government Communications made heroic efforts to restore the lines, but the enemy bombed, and communications were again disrupted. Bypass lines were also disrupted. At this time, I.V. Stalin needed contact with the Stalingrad Front. A.N. Poskrebyshev, Stalin’s assistant, called me and asked me what to report to him - when there would be contact. I answered - in 2 hours (in the hope that during this time the line would be restored). I contacted our unit and received a response that the bombing had intensified. He gave the command to make a “temporary job” - to lay the PTF-7 field cable along the ground. 2 hours later Poskrebyshev called again. I informed him that it would take another 40 minutes. After 40 minutes, Poskrebyshev suggested personally reporting to Stalin when there was communication. But at this time the line was restored. Stalin spoke with headquarters, and a personal report was not required. Soon, People's Commissar of Internal Affairs Beria and Deputy People's Commissar of Defense People's Commissar of Communications I. T. Peresypkin were summoned to Stalin. Stalin expressed great displeasure that there was no stable connection with Stalingrad and recalled that back in 1918 he had a reliable connection with Lenin while on the Tsaritsyn front.

It was instructed to make proposals providing for the responsibility of one body for the unconditional reliability of communications. Such proposals have been developed. The GKO Decree of January 30, 1943 was issued. Government Communications Troops were created, whose task was to ensure the construction, maintenance and military protection of Government Communications lines from the Headquarters of the Supreme High Command to the fronts and armies. Other lines running across the country to the republics, territories and regions, used for Government communications, remained in the service of NK Communications.

The Department of Government Communications Troops was created in the NKVD. It was headed by P.F. Uglovsky, who had previously been the head of communications for the border troops. The head of the line service in the Government Communications Department, K. A. Alexandrov, a major line specialist, became his deputy. At the fronts, Government Communications Departments were created, to which units of the Government Communications troops were subordinated - individual regiments, battalions, companies. It seems somewhat strange that the decision to create two divisions in the NKVD in charge of Government Communications - the Department and the Directorate of Troops. However, this was dictated by the specifics of the work of state security agencies: there were operational units and troops performing specific military tasks at the direction of operational agencies.

Similar to this structure, the NKVD had an operational body - the Government Communications Department, which was in charge of organizing communications, its development, technical equipment, station service, issues of maintaining secrecy - and troops that built communication lines, ensured their uninterrupted operation and guarded in pairs and secret ambushes in vulnerable places, excluding the possibility of connecting to eavesdropping lines, prevented possible sabotage.

The department and the Troops Directorate worked closely throughout the war, and there were no misunderstandings in their relationship. They united in 1959; the structure of Government Communications received its logical conclusion. The agencies and troops were able to comprehensively carry out tasks of organizing and ensuring communications in difficult combat conditions.

Communication was organized along “axes” and directions. The center line was drawn towards the front headquarters. As a rule, they tried to build two axial lines along different routes; a direction was laid towards the armies - one line of communication. Two chains were suspended on it: one was sealed with HF equipment, and the other, a service one, was intended for communication with service posts.

In the army areas, during the construction of communication lines, we often came into contact with the NK defense signalmen. They pulled one line, which was used for compaction, and the “middle point” was transferred to army signalmen for telegraph communication using the Baudot system. HF communications were organized at the main command post (CP), reserve (ZKP) and forward (PKP) points. When the front commander left for the troops, he was accompanied by a Government Communications officer with ZAS equipment. HF communications were organized at the location of the commander, taking into account existing army communication lines or NK communication lines.

The Government Communications troops received their baptism of fire in the battle on the Oryol-Kursk Bulge, where five fronts operated simultaneously and several dozen HF stations were deployed. The signalmen successfully completed the assigned tasks, ensuring continuous communication between Stavka and all fronts, armies and two representatives of Stavka-G. K. Zhukov and A. M. Vasilevsky, who had their own HF stations.

After the Battle of Orel-Kursk, the troops began a rapid offensive, liberating our territories from the German occupiers. The speed of advance of combined arms armies reached 10-15 km per day, and that of tank armies - up to 20-30 km. At such a pace, the troops did not have time to build permanent air lines. It was necessary to arm them with so-called cable-pole lines, which were deployed during the rapid advance of troops as temporary ones and were subsequently replaced with permanent ones if it was necessary to maintain this direction. This is how the line service was created.

Issues of technical equipment for front-line and army HF communication stations were also resolved. In Government Communications, to organize high-frequency channels, the SMT-34 type 10-40 kHz spectrum multiplexing system adopted at that time on the long-distance NK communication network was used. It was purely stationary equipment. The racks, 2.5 m high, weighed more than 400 kg. The stand could be transported in a car by placing it on its side. She couldn't stand any shaking. Often after transportation it took days to restore the installation. There were also no switches, batteries, block stations or other equipment adapted to field conditions. Everything had to be created anew.

The only base for the production of long-distance communication equipment at that time was the workshop at the Krasnaya Zarya plant in Leningrad. But by the end of 1941, Leningrad found itself under siege. Emergency measures were taken to evacuate this workshop to Ufa, where Plant No. 697 for the production of long-distance communication equipment and a research institute were created.

Thanks to the hard work of teams headed by prominent specialists A, E. Pleshakov and M. N. Vostokov, the SMT-42 equipment was created (in the 10-40 kHz spectrum), and then the SMT-44 equipment (field versions of the SMT-34 equipment; height - 60 cm, weight – 50 kg). It was convenient for quickly deploying and collapsing HF stations and could withstand shaking during transportation. NVChT equipment in the spectrum up to 10 kHz was also developed, and a fourth channel in the spectrum above 40 kHz was added to the SMT equipment; switches and ZAS equipment were created in the field. For the creation of this complex, the authors were awarded the State Prize. Government communications received a complete set of field communications equipment, which made it possible to quickly resolve issues related to the organization of HF communications.

An attempt was made to reserve wired communications with the fronts using radio communications. At that time, only the KB band could be used for radio communications. Industrially produced RAF and PAT stations were taken. But they have not found widespread use. The ZAS equipment used on radio channels presented high requirements to the quality of the channel, which was difficult to achieve on KB lines. In addition, subscribers who were warned that they were receiving radio communications often refused to speak. I remember such a case. After the end of the war, a peace conference was held in Paris. The Soviet delegation was headed by V. M. Molotov. We organized wired communications to Berlin using our own communication lines, and from Berlin to Paris the line was provided by the Americans. While we were having open conversations, the connection worked perfectly, as soon as the ZAS was turned on, the connection stopped. We also provided for radio backup using stationary radio communications equipment. But Molotov refused to speak on the radio, saying that he had to recognize the person he was talking to by his voice. With the ZAS equipment that was used, this was difficult to achieve. I had to quarrel with the Americans and achieve stable operation of wired communications.

A description of the activities of Government Communications during the Great Patriotic War will not be complete if we do not dwell on some of the most significant operations and events.

When Leningrad was blockaded by the Germans at the end of 1941, the question of HF communications with the Leningrad Front and the city became acute. NK Communications organized radio communications. We could not use this connection due to the lack of appropriate ZAS equipment. A wire line was needed. NK Communications and NK Defense decided to urgently lay the cable in the only possible direction - along the bottom of Lake Ladoga. The laying was already under enemy fire. As a result, a wired air connection was organized with Leningrad through Vologda to Tikhvin, then by cable to Vsevolozhskaya, then again by air to Leningrad. Headquarters had a stable HF connection with Leningrad throughout the war.

By the summer of 1942, the Germans had recovered from their defeat near Moscow and began an offensive in the southern direction. The Voronezh Front was created. I and a group of employees flew to Povorino, where the headquarters of the Voronezh Front was supposed to move. Soon the first deputy people's commissar of communications, A. A. Konyukhov, arrived there. We began work on installing nodes and organizing communications. The Germans bombed Povorino every day. During the bombing, we hid in a nearby ravine, and then continued our work again. But one day, returning from shelter, we saw the burning ruins of the buildings where we had placed our units. All equipment was also lost. "Claws" and a telephone were found. We climbed onto the entrance pole with the remaining wires. A. A. Konyukhov and I reported to our superiors about what had happened. But by this time the situation had changed and HF communications were deployed in the village of Otradnoye, where the front headquarters soon moved. Soon I was ordered to urgently leave for Stalingrad.

A very difficult situation developed in Stalingrad. All main lines of communication between Moscow and Stalingrad ran along the right bank of the Volga. After the Germans reached its bank above Stalingrad, in the town of Rynok, and below Stalingrad, in the Krasnoarmeysk area, the city found itself surrounded. On August 23, 1943, the Germans launched a massive raid. The whole city was burning. Signalmen of NK Communications, under the most difficult conditions, transported all the equipment of the intercity station to the left bank and installed a reserve node in the town of Kapustin Yar, with access to Astrakhan and Saratov. There were no existing communication lines left in Stalingrad. The headquarters of the Stalingrad Front was on the right bank. Communication with him could only be organized from the left bank. The Stalingrad HF station was also moved to the left bank in the town of Krasnaya Sloboda. Together with I.V. Klokov, the responsible representative of NK Communications, we gave instructions to build a line across the Volga.

First of all, they checked whether it was possible to use the existing cable crossing in the Market area. It was difficult to approach the cable box - the Germans controlled all approaches. And yet, on our bellies, we crawled up to her and checked the serviceability of the cable. It worked, but the Germans answered at the other end. It was impossible to use this cable for our purposes. There was only one way out - to lay a new cable crossing across the Volga. We didn't have a river cable. We decided to install the PTF-7 field cable, which is not suitable for working under water (it got wet after 1-2 days). We called Moscow to urgently send a river cable.

The laying had to be carried out under continuous mortar fire. Oil barges floating along the river caused great damage. Pierced by shells, they floated downstream, gradually plunging into the water, and cut our cables. Every day we had to put in more and more new bundles. The HF communications switch was installed in the dugout where the front command was located. LF communications were transmitted to this switch from the HF station located on the left bank.

Finally, the river cable arrived. The drum weighed more than a ton. No suitable boat was found. They made a special raft. At night we started laying, but the Germans spotted us and destroyed the raft with mortar fire. I had to start all over again. Finally the cable was installed. Before the freeze-up it worked reliably. Later, in addition to it, an overhead line was laid along the ice. The pillars were frozen into ice.

In February the Germans were defeated. Communications with Stalingrad began to work according to the pre-war scheme.

Great difficulties were encountered in organizing Government communications at the Tehran Conference of the three allied powers. In peacetime, the Soviet Union did not have wired communications with Tehran. It was necessary to organize it. The task was complicated by the fact that Stalin, as the Supreme Commander-in-Chief, needed communication not only with Moscow, but also with all fronts and armies.

I and a group of specialists went to Tehran two months before the meeting to study the situation, make a decision and organize the necessary work on installing an HF station and preparing communication lines. Having familiarized myself with the situation, I realized that the only line that can solve the problem is the Ashgabat-Kzyl-Aravat-Astara-Baku air line, laid along the shore of the Caspian Sea. By agreement with Iran, this line was built by the NK Communications as a bypass for communication with the Transcaucasus, since the Germans were breaking through to the Caucasus and could cut the lines going to Baku, the Transcaucasian Front, Georgia, and Armenia. It was necessary to find a way out of Tehran onto a bypass line. The Iranian communication lines available in this direction were in a disgusting state: they went through rice fields and were inaccessible for service. The poles were lopsided, the insulators on many of the poles were missing, and the wires were hanging on hooks or simply nailed to the poles.

The so-called Indo-European line of communication running through Iran has more or less been preserved. They decided to use it. At one time, it was built by the British on metal poles to connect London with India. The line was not used for its intended purpose and was operated by Iranian signalmen. It was decided to place the Soviet delegation in the building of the USSR Embassy, ​​and it was also planned to locate a HF station there. The indicated line of communication was opened at the embassy. At the Sari and Astara points we made interchanges on our line. Now from Tehran there were two exits to Baku through Astara and to Ashgabat-Tashkent through Kzyl-Aravat (Turkmenistan). Thus, although with great difficulties, it was possible to ensure stable HF communications for the entire duration of the Tehran Conference.

The rapid advance of our troops in 1943-1945. required full tension in the work of the Government Communications bodies and troops. A characteristic feature of the strategic offensive was the continuous increase in its territory, gradually covering a strip of up to 2000 km. The depth of attacks on the enemy reached 600-700 km. Front headquarters moved up to three times in one operation, and army headquarters moved up to eight times. The closest interaction was established between the bodies and troops of the Government Communications and the signalmen of the NK Communications and NK Defense. The joint efforts were carried out to reconnaissance of the surviving permanent communication lines. The issues of joint construction and restoration of lines were carefully coordinated. During the summer-autumn operations of 1943, Government Communications troops built 4,041 km of new permanent lines, restored 5,612 km of lines, suspended 32,836 km of wires, and built 4,071 km of pole lines. Departments and troops were gaining experience; they were already capable of solving complex problems of organizing HF communications in any situation.

If we evaluate the completed tasks, we should focus on the proposed movements of the Supreme High Command Headquarters from Moscow to other cities. As you know, Headquarters was in Moscow throughout the war, and the Supreme Commander-in-Chief went to the front only once - to the Rzhev region. HF communication with him was maintained by mobile means. However, the decision to move Headquarters was made twice - in 1941 and 1944. In 1941, when the Germans came close to Moscow and there were 20-30 km left to the front line, the leadership of the General Staff turned to Stalin with a proposal to move Headquarters inland. According to the provisions on the conduct of military operations, the Supreme High Command should be located at a distance of 200-300 km from the front line. The situation required determining the point where the Headquarters could be moved.

As Marshal I. T. Peresypkin told me, Stalin came up to the map and said: “When Ivan the Terrible took Kazan, he had a headquarters in Arzamas, we will stop at this city.” With a group of specialists, I went to Arzamas and began organizing work on the installation of an HF station. A two-story house was chosen for Stalin, the first floor of which was given over to the HF station. During installation, the possibility of going to the fronts was provided, bypassing Moscow. However, only the Chief of the General Staff, Marshal B. M. Shaposhnikov, arrived in Arzamas and soon left back to Moscow. Instead of Arzamas, they began to prepare premises in Gorky to house the Headquarters and the Government. But he too was given the all clear. The work stopped and we returned to Moscow.

The second time the decision to move Headquarters was made in 1944, after the successful completion of Operation Bagration and the liberation of Minsk. Marshal I.T. Peresypkin informed me about this and suggested that I go to Minsk. We left together with K. A. Alexandrov. On the way, discussing the situation in Minsk, we came to the conclusion that it was necessary to strengthen communications between Minsk and Moscow. In this direction there was only one circuit, compacted with three-channel equipment. It was decided to suspend three more, two of them by the forces of the NK Communications and NK Defense and one by the troops of the Government Communications. Communication centers were deployed in Minsk and great work for the construction of bypass lines around the city. After some time the all clear was given again. The headquarters remained in Moscow.

Attaching particular importance to the organization of Government communications with the fronts and armies, we should not forget about the work of the entire communication network with the republics, territories and regions, especially since a significant number of new HF stations were opened in the rear - at factories of the defense industries that manufacture weapons for the army, at the places of formation of reserve armies - and a number of others related to the needs of the front. The state of the national NK communications network played a major role in the successful work of Government Communications. Sometimes additional costs for NK communications were necessary. And, I must say, we met with complete understanding from the leadership of the People’s Commissariat of Communications, People’s Commissar I. T. Peresypkin, as well as his deputies I. S. Ravich and I. V. Klokov, who interacted closely with us.

On the eve of Victory Day in 1965, the Pravda newspaper wrote: “Special signal troops operated successfully on the fronts of the Patriotic War. In difficult combat conditions, signalmen of the state security agencies ensured stable closed communication between the leaders of the Party and the Government, the Headquarters of the Supreme High Command with the fronts and armies, skillfully stopped attempts by enemy saboteurs to disrupt communications."

Marshal of the Soviet Union I. S. Konev in his memoirs spoke about HF communications as follows: “In general, it must be said that this HF communications, as they say, was sent to us by God. It helped us out so much, it was so stable in the most difficult conditions that we need pay tribute to our equipment and our signalmen, who specially provided this high-frequency connection and in any situation literally followed on the heels of everyone who was supposed to use this connection during the movement."

The bodies and troops of Government Communications coped well with the tasks assigned to them, making a great contribution to the Victory over Nazi Germany.

For 12 years, he held the position of deputy chairman of the Interdepartmental Coordination Council for the creation of the country's Unified Automated Communications Network, during the Great Patriotic War, Pyotr Nikolaevich Voronin ensured communications between the Headquarters of the Supreme High Command and the headquarters of the fronts and armies. He was involved in the construction of backup nodes and communication lines in Moscow and around the capital. He took an active part in organizing communications during the days of the defense of Moscow, during the Battle of Stalingrad, lifting the siege of Leningrad, conducting the Oryol-Kursk, Berlin and other operations. Provided communications for the Supreme Commander-in-Chief during the Tehran and Potsdam Conferences. Awarded the Order of the October Revolution, Orders of the Patriotic War I and II degrees, three Orders of the Red Banner, three Orders of the Red Banner of Labor, two Orders of the Red Star, other military and labor orders and medals.

The division of the vertically integrated structure of the post-Soviet electric power industry, the complication of the management system, an increase in the share of small-scale electricity generation, new rules for connecting consumers (reducing the time and cost of connection), while increasing requirements for the reliability of energy supply entails a priority attitude to the development of telecommunications systems.

In the energy sector, many types of communication are used (about 20) differing in:

• purpose,
• transmission medium,
• physical operating principles,
• type of transmitted data,
• transmission technologies.

Among all this diversity, HF communication via high-voltage power transmission lines (VL) stands out, which, unlike other types, was created by energy specialists for the needs of the electric power industry itself. Other types of communications equipment originally designed for communications systems common use, to one degree or another, adapts to the needs of energy companies.

The very idea of ​​using overhead lines for distributing information signals arose during the design and construction of the first high-voltage lines (since the construction of parallel infrastructure for communication systems entailed a significant increase in cost); accordingly, already in the early 20s of the last century, the first commercial HF communication systems were put into operation.

The first generation of HF communications was more like radio communications. The connection of the transmitter and receiver of high-frequency signals was carried out using an antenna up to 100 m long, suspended on supports parallel to the power wire. The overhead line itself was the guide for the HF signal - at that time, for speech transmission. Antenna connection has been used for a long time to organize communication between emergency crews and in railway transport.

Further evolution of HF communications led to the creation of HF connection equipment:

• coupling capacitors and connection filters, which made it possible to expand the band of transmitted and received frequencies,
• RF barriers (barrier filters), which made it possible to reduce the influence of substation devices and overhead line inhomogeneities on the characteristics of the RF signal to an acceptable level, and accordingly, improve the parameters of the RF path.

The next generations of channel-forming equipment began to transmit not only speech, but also telecontrol signals, protective commands for relay protection, emergency automation, and made it possible to organize data transmission.

As a separate type of HF communication, it was formed in the 40s and 50s of the last century. International Standards (IEC) have been developed to guide the design, development and production of equipment. In the 70s in the USSR, through the efforts of such specialists as Shkarin Yu.P., Skitaltsev V.S. mathematical methods and recommendations for calculating the parameters of HF paths were developed, which significantly simplified the work of design organizations when designing HF channels and choosing frequencies, increased specifications input HF channels.

Until 2014, HF communications were officially the main type of communications for the electricity sector in the Russian Federation.

The emergence and implementation of fiber-optic communication channels, in the context of widespread HF communications, has become a complementary factor in the modern concept of the development of communication networks in the electric power industry. Currently, the relevance of HF communications remains at the same level, and intensive development and significant investments in optical infrastructure contribute to the development and formation of new areas of application of HF communications.

The undeniable advantages and the presence of vast positive experience in the use of HF communications (almost 100 years) give reason to believe that the HF direction will be relevant both in the near and long term, and the development of this type of communication will make it possible to solve both current problems and contribute to the development of the entire electric power industry industry.

To transmit information between protections and automation at the ends of a high-voltage line, a channel created for high-frequency currents using a phase-to-ground connection scheme is used.

The path includes one phase of the operating overhead line, which is connected to the ground through coupling capacitors at substations to create a closed loop for HF currents.

Most often, two remote phases “A” and “C” are used on the line to transmit commands at frequency No. 1 through one of them from the substation, and through the second to receive commands at frequency No. 2.

Design and purpose of the HF communication channel. Transmitters and receivers of high-frequency signals are installed at each substation. In this case, modern RF transceiver equipment is made on the microprocessor base of ETL640 v.03.32 terminals from ABB.

To process signals at each frequency, its own transceiver is manufactured. Therefore, one substation requires 2 sets of terminals configured to simultaneously receive and transmit signals along different phases of the overhead line.

The connection of the HF transceiver to the overhead line is carried out by special equipment that separates high voltage from low-current equipment and creates a highway for transmitting HF signals. It is completed with:

High-voltage coupling capacitor (CC);
- connection filter (FP);
- high-frequency jammer (HF);
- HF cable.

Purpose high voltage capacitor communication consists of reliable isolation from the ground of power transported via overhead lines at industrial frequency and passing high-frequency currents through it.

In the photograph of the line in question, there are 3 capacitors with PT in each phase. They are used to communicate with far-end equipment for the following purposes:

1. Transfer of commands to RZ and PA;
2. Receiving commands RZ and PA;
3. Work of HF equipment of the communication service.

To separate the RF signal from high voltage equipment substation into the phase wire of overhead lines high voltage An HF suppressor is installed. which limits the amount of RF signal loss through parallel circuits.

Industrial frequency currents pass through it well and high-frequency currents do not pass through. The VZ consists of a reactor (power coil) passing the operating current of the line, and adjustment elements connected in parallel with the reactor.

To match the parameters of the input impedances of the HF cable and line, a connection filter is used, which is performed as an air transformer model with taps from the windings, allowing the necessary adjustments to be made. The RF cable connects the connection filter to the transceiver.

High frequency transceivers (ETL640), purpose. Transceivers of the ETL640 type (PRM/PRD) are designed to transmit and receive HF signals in the form of commands generated by relay protection (RP) and emergency automatics (EA) to the opposite end of the overhead line.

Checking the serviceability of the HF channel. Complex RF transmission path equipment is located at distances of hundreds of kilometers and requires monitoring and maintaining its integrity. ETL640 transceivers at the ends of overhead lines are constantly in normal mode operations exchange (transmit/receive) control frequency signals.

When the signal decreases in magnitude or its frequency changes beyond permissible limits, a fault alarm is triggered. After restoration of functionality, the transceiver automatically returns to normal operation.

Signal exchange. Signals are transmitted and received at dedicated frequencies, for example:

Complex on phase “A”: Tx: 470 + 4 kHz, Rx: 474 + 4 kHz;
- complex on phase “C”: Tx: 502 + 4 kHz, Rx: 506 + 4 kHz.

The ETL640 equipment is designed for round-the-clock continuous operation in heated control rooms.

Reception and transmission of commands. Terminals No. 1 and No. 2 of the ETL640 complexes receive and transmit 16 commands each from the RZ and PA.

ETL640 transceiver commands. Typical commands of the transceiver of any ETL640 complex can look like:

1. Disconnection of 3 phases of the 330 kV overhead line from the far end of the overhead line without control with the prohibition of TAPV and start-up from the breaker failure or ZNR complex No.... REL-670;

2. Disconnection of 3 phases of the 330 kV overhead line from the far end of the overhead line with control by measuring elements Z3 DZ and the 3rd stage of the NTZNP complex No.... REL670 protections without prohibiting TAPV and starting from the 3-phase shutdown factor of the complex No.... REL protections;

3. Teleacceleration of remote protection with an effect on one or 3-phase shutdown of a 330 kV overhead line from the far end of the overhead line, with control of the parameters of stage Z3 of the remote protection complex No.... of REL670 protection with OAPV/TAPV and starting from stage Z3 of the remote protection complex No.... of protection REL- 670;

4. Teleacceleration of NTZNP with an effect on one or 3-phase shutdown of a 330 kV overhead line from the far end of the overhead line with control of the parameters of stage Z3 of NTZNP complex No.... REL670 protections with OAPV/TAPV and starting from the measuring element of the 3rd stage of NTZNP complex No.... REL670 protections ;

5. Fixation of line disconnection from its side of the overhead line and action in the AFOL logic circuit of the complex No.... protection of relay protection and automation. Start from the output relay of the AFOL logic circuit of complex No.... protection of relay protection and automation when the line is disconnected on its side;

6. III stage OH, acting on start-up:
- 5th command AKAP prd 232 kHz VL No....;
- 2nd command AKPA prd 286 kHz overhead line No....;
- 4th team ANKA prd 342 kHz VL No....

7. Fixing the switching on of the line on its part and the action in the AFOL logic circuit of the complex No.... of the VL RPA protection with starting from the output relay of the AFOL logic circuit of the complex No.... of the VL-330 RZA protection when switched on from its side;

8. Start from the 1st stage of the SAPAH circuit... with start:
- 6th team ANKA prd 348 kHz VL No....;
- 4th command AKAP prd 122 kHz VL No....

9. 3rd stage of load shedding with action...

Each team is formed for specific conditions of the overhead line, taking into account its configuration in the electrical network and operating conditions. The output relays of the HF equipment and switching devices are located in a separate cabinet.

Overhead line alarm circuits. Terminal signaling. On the front panel of the terminals there are 3 LEDs that reflect the state of the REL670 device itself and 15 LEDs that indicate protection activations, malfunctions and the status of operational switches.

The LEDs of the terminals REL670 (protection of the 1st and 2nd complexes) and REC670 (automation and breaker failure of the 1st and 2nd complexes B1 and B2) of the first six numbers are red. LEDs numbered 7 to 15 are yellow.

LEDs for status indication. Above the LCD block of the REC670 and REL670 terminals are inserted 3 LED indicator“Ready”, “Start” and “Trip”. To indicate various information they glow in different colors. The green color of the indicator indicates:

Device operation - stable glow;
- internal damage - flashing;
- lack of operative current supply - darkening of color.

The yellow indicator color indicates:

Starting the emergency recorder - steady glow;;
- the terminal is in test mode - accompanied by blinking.

The red color of the indicator indicates the issuance of an emergency shutdown command (stable light).

REC670 terminal LED signaling table

Resetting and testing the alarm. Resetting the alarm, counters for recording the reception and transmission of HF commands and information on the DZ and NTZNP zones for the terminal is done by pressing the SB1 button (alarm reset) on the front side of the cabinet.

To test the LEDs of the REL670 (REC670) terminals, you need to press and hold the SB1 button for more than 5 seconds.

Panel-wide light alarm. On the front side of the REС670 cabinets there are lamps:
- HLW – automatic reclosing works, ZNF, breaker failure;
- HLR2 – malfunction of automation systems and breaker failure level V-1 or V-2.

On the front side of REL670 cabinets there are lamps:
- HLW – protection work;
- HLR1 – the defense complex is removed;
- HLR2 – malfunction of protection systems.

On the front side of ETL cabinets there are alarm lamps:
- HLW1 – malfunction of ETL 1st complex;
- HLW2 – ETL 2nd complex malfunction.

Prospects for the development of overhead power line equipment. Time-tested air circuit breakers for high-voltage power lines are gradually being replaced by modern SF6 designs, which do not require constant operation of powerful compressor stations to maintain air pressure in tanks and air lines.

Bulky analog relay protection and control devices for high-voltage equipment, requiring close attention from maintenance personnel, are being replaced by new microprocessor terminals.

Power line communications have once again become a hotly debated topic, at various scientific levels and in the press. This technology has seen many ups and downs in the past few years. Many articles with conflicting views (conclusions) have been published in special periodicals. Some experts call data transmission over electrical networks a dying technology, while others predict a bright future in medium and low voltage networks, for example, in offices and homes.

The technology that today is called HF communication over power lines actually covers several different and independent areas and applications. This is, on the one hand, narrowband point-to-point transmission over high voltage overhead lines (35-750 kV), and on the other hand, broadband network-wide data transmission (BPL Broadband Power Line), in medium and low voltage networks (0.4-35 kV ).

Siemens is a pioneer in both directions. The first HF systems on high-voltage lines by Siemens were implemented back in 1926 in Ireland.

The attractiveness of this technology for power grid operators is that they use their own power grid infrastructure to transmit information signals. Thus, the technology is not only very economical - there are no ongoing costs for maintaining communication channels, but also allows energy supply enterprises to be independent of communication service providers, which is especially important in emergency situations, and is even required at the legislative level in many countries. HF communications is a universal technological solution for both enterprises involved in the transmission and distribution of electricity, and companies focused on providing services to the public.

HF communications in high voltage networks (35-750 kV)

During rapid development information technologies(1990s) Electric utilities in industrialized countries made significant investments in the installation of optical communication lines (FOCL) over high-voltage overhead lines in the hope of securing a lucrative share of the overheated telecommunications market. At this time, the good old HF technology was buried again. Then the inflated information technology bubble burst, and sobering up occurred in many regions. And it was in energy networks that the installation of optical lines was suspended for economic reasons, and the technology of HF communication over overhead lines acquired a new meaning.

As a result of the use of digital technologies on high-voltage networks, new requirements for HF systems have emerged.

Currently, data and speech transmission is carried out via fast digital channels, and signals and data of protection systems are transmitted simultaneously (in parallel) via HF lines and digital channels (fiber optic lines), forming reliable redundancy (see the next section).

On network branches and long sections of power lines, the use of fiber-optic lines is not economically feasible. Here, HF technology offers a cost-effective alternative for transmitting speech, data and command signals of relay protection and emergency control systems (relay protection relay protection, emergency control equipment emergency automation) Figure 1.

Due to the rapid development of power industry automation systems and digital broadband networks on trunk lines, the requirements for modern systems HF communications.

Today, HF network taps are viewed as a system that reliably transmits protection systems data and provides a transparent, user-friendly interface to data and voice from broadband digital networks to the end consumer with significantly greater throughput compared to conventional analog systems. From a modern point of view, high throughput can only be achieved by increasing the frequency band. What was impossible in the past due to the lack of free frequencies is now being realized thanks to the widespread use of optical lines. Therefore, HF systems are heavily used only on network branches. There are also options when individual sections of networks are interconnected by fiber optic lines, which allows the use of the same operating frequencies much more often than in the case of integrated HF communication systems.

In modern digital RF systems, the information density when using fast signal processors and digital ways modulation can be increased compared to analog systems from 0.3 to 8 bits/sec/Hz. Thus, for a frequency band of 8 kHz in each direction (reception and transmission), a speed of 64 kbit/s can be achieved.

In 2005, Siemens introduced new digital RF communications equipment “PowerLink”, confirming its leading position in this area. PowerLink equipment is also certified for use in Russia. With PowerLink, Siemens has created a multi-service platform suitable for both analog and digital applications. Figure 2.

Below are the unique features of this system

Optimal use of the allocated frequency: The best RF communications equipment allows data to be transmitted at speeds of 64 kbps or less, while PowerLink has a rate of 76.8 kbps, occupying a bandwidth of 8 kHz.

More voice channels: Another Siemens innovation implemented in the PowerLink system is the ability to transmit 3 analog voice channels at 8 kHz bandwidth instead of 2 channels in conventional equipment.

CCTV: PowerLink the first RF communication system allowing the transmission of a video surveillance signal.

AXC (Automatic Crasstalk Canceller) Automatic Crosstalk Canceller: Previously, close transmit and receive bands required complex RF tuning to minimize the influence of the transmitter on its receiver. The patented AXC unit has replaced the complex hybrid setup and associated module, and the transmission and reception quality has been improved.

OSA (Optimized Sub channel Allocation) Optimal distribution of subchannels: Another patented solution from Siemens guarantees optimal resource allocation when configuring services (Speech, data, security signaling) in the allocated frequency band. As a result, the final transmitting capacity increases to 50%.

Increased flexibility: To ensure investment security and future use, Siemens has implemented the “ease-up!” function. for simple and reliable updates.

Multifunctional equipment: By carrying out a project based on combined PowerLink equipment, you can forget about the limitations that conventional terminals had when planning frequencies. With PowerLink you can design an RF communications system with a full range of services (voice, data, PA and PA signals) in the available bandwidth. One PowerLink kit can replace three (3) conventional analog systems Figure 3.

Transfer of data from security systems

RF communication technology continues to play an important role in the field of data transmission for protection systems. On main and high-voltage lines with voltages above 330 kV, as a rule, double protection systems are used with different ways measurements (eg differential protection and distance protection). Security systems are also used to transmit data. various ways transmissions to ensure complete redundancy, including communication channels. Typical communication channels in this case are a combination of digital channels via optical lines for differential protection data and analog RF channels for transmitting distance protection command signals. For transmitting protection signals, HF technology is the most reliable channel. HF communication is a more reliable data transmission channel than others, even optical lines cannot provide such quality over a long period of time. Outside the main lines and at the ends of the network, HF communications often become the only channel for transmitting protection system data.

The proven Siemens SWT 3000 system (Figure 4) is an innovative solution for transmitting PA commands with the required maximum reliability and at the same time minimal command transmission time in analogue and digital communication networks.

Many years of experience in the field of transmission of protective signals allowed us to create a unique system. Thanks to a complex combination of digital filters and systems digital processing signals, it was possible to so suppress the influence of impulse noise - the strongest interference in analog communication channels - that even in difficult real conditions, reliable transmission of RE and PA commands is achieved. All known operating modes of direct trip or permissive operation with individual timers and coordinated or uncoordinated transmission are supported. The selection of operating modes is carried out using software. Emergency control functions specific to Russian power grids can be implemented on the same SWT 3000 hardware platform.

When using digital interfaces, device identification is carried out by address. In this way, it is possible to prevent other devices from accidentally connecting via digital networks.

The flexible two-in-one concept allows the SWT 3000 to be used in all available communication channels - copper cables, high-voltage lines, optical lines or digital in any combination Figure 5:

• digital + analog on one platform;
• 2 redundant channels in 1 system;
• duplicated power supply in 1 system;
• 2 systems in 1 environment.

As a very cost-effective solution, the SWT 3000 can be integrated into a PowerLink RF system. This configuration provides the possibility of duplicate transmission: analog via HF technology and digital, for example, via SDH.

HF communications in medium and low voltage networks (distribution networks)

Unlike HF communications over high-voltage power lines, in medium- and low-voltage networks, HF systems are designed for point-to-multipoint operation modes. These systems also differ in data transfer speed.

Narrowband systems (digital channels DLC communications) have long been used in power grids to determine the location of faults, remote automation and transmission of measurement data. Transfer speed depending on application from 1.2 kbit/s to< 100 кбит/с. Передача сигналов в линиях среднего напряжения осуществляется емкостным способом по экрану кабеля среднего напряжения.

Since 2000, Siemens has successfully offered digital system DCS3000 communications. Constant changes in the state of the power grid, caused by frequent switching or connecting various consuming devices, require the implementation of a complex technological task - an integrated, productive signal processing system, an implementation that has only become possible today.

The DCS3000 uses high-quality OFDM data transmission technology orthogonal frequency division multiplexing. Reliable technology ensures automatic adaptation to changes in the transmission network. In this case, the transmitted information in a certain range is optimally modulated on several separate carriers and transmitted in the CENELEC range standardized for electrical networks (from 9 to 148 kHz). While maintaining the permitted frequency range and transmission power, it is necessary to overcome changes in the power grid configuration as well as typical power grid disturbances such as broadband noise, pulsed noise and narrowband noise. Additionally, reliable support for data transfer using standard protocols is provided by repeating data packets in the event of a failure. The DCS3000 system was designed for low-speed data transmission related to electrical services in the range from 4 kHz to 24 kHz.

Medium voltage networks are usually operated in an open circuit, providing two-way access to each transformer station.

The DCS3000 system consists of a modem, a base unit (BU) and inductive or capacitive communication modules. Communication is carried out according to the master-slave principle (master slave). The main DCS3000 base unit in the transformer substation, through the slave DCS3000 base units, periodically queries data from connected telemetry devices and transmits them further to the control panel Figure 6. Data packets can be transmitted to the control panel and to telemetry devices according to the IEC61870-5-101 standard or DNP3.

The input and output of the information signal is implemented before or after distribution devices, since the cable shield is grounded only at the input ends, using simple inductive connections (CDI). Separable ferrite cores can be mounted on the cable shield or on the cable. Depending on specific conditions. It is not necessary to disconnect the medium voltage line during installation.

For other cables or overhead lines, the input is through phase conductors using capacitive connections (CDC). For different voltage levels, Siemens offers different connections for cable, overhead and gas-insulated distribution systems.

The distribution network can be created with a different topology. The DCS3000 is ideal for medium voltage networks with linear, tree or star topologies. If there is a shielded line with a protection transformer between two transformer stations, it can be connected directly to the DCS3000. To ensure constant access to the channel, it is desirable to create a logical ring. If this is not possible due to the network topology, then the two lines can be combined into a logical ring using the built-in modem.

The DCS3000 system developed by Siemens is the only successfully implemented communication system in a distribution network. Among other orders, Siemens created communication systems in Singapore for Singapore Power Grid and in Macau for CEM Macao. The argument for the implementation of these projects was the opportunity to avoid large costs in the construction of new communication line infrastructure. For 25 years, Siemens has been supplying Singapore PG with communications solutions for data transmission over shielded cables. In 2000, Siemens received an order to supply 1,100 DCS3000 systems, which are used by Singapore PG in the 6 kV distribution network for automation and fault localization. The distribution network is mainly built according to a ring pattern.

CEM Macao operates its electricity distribution network at only one voltage level. Therefore, the requirements presented here are similar to those for a high voltage network. Special requirements are placed on the reliability of the communication system being created. Therefore, the DCS3000 system has been expanded with redundant base units and redundant control panel inputs. The medium voltage network is built in the form of a ring and provides data transmission in two directions. Over the course of many years, more than 1,000 DCS3000 systems have ensured the reliable operation of the established communication network and serve as proof of its effectiveness.

In Egypt, transformer stations were not equipped with remote maintenance input channels. Creating new connections was expensive. It was possible in principle to use radio modems, but the number of available frequencies for individual transformer stations was limited and significant additional operating costs could not be avoided. An alternative solution was the DCS3000 system. Data from remote telemechanics terminals was transmitted to the transformer substation. A high-level telemechanics system collected data and transmitted it via radio to data concentrators, from where it was in turn transmitted via existing remote control lines to the control center. For the two projects, Siemens supplied more than 850 DCS3000 systems to MEEDCO (10 kV) and DELTA (6 kV).

Broadband systems(Broadband Power Line BPL) After many years of pilot installations around the world and numerous commercial projects, the second generation of BPL technology has matured to the point where it has become an attractive alternative for other broadband access networks.

In low voltage networks, BPL gives the provider the opportunity to implement broadband access to “triple play” services at the “last mile”:

• high-speed Internet access;
• IP telephony;
• video.

Users can enjoy these offered services by connecting to any electrical outlet. Organization at home is also possible local network for connecting computers and peripheral devices without laying additional cables.

For utilities, BPL is not considered today. The only service used today, remote meter reading, uses cost-effective solutions such as GSM or slow DLC systems. However, when combined with broadband services, BPL becomes attractive for meter reading as well. Thus, “triple play” turns into “quad play” (Figure 8).

In a medium voltage network, BPL is used for broadband services as a transport link to the nearest provider access point. For utilities currently, remote reading of meters of ASKUE devices narrow-band systems operating in the range allocated by CENELEC for utilities from 9 to 148 kHz are sufficient. Of course, medium voltage BPL systems with mixed services (“shared channel”) can be used for both the provider and the utility.

The importance of BPL is growing, as evidenced by increased investment in this type communications between utilities, providers and industry. In the past, the main players in the BPL market were predominantly small enterprises specializing exclusively in this technology, but today large concerns are entering this market, for example, Schneider Electric, Misubishi Electric, Motorola and Siemens. This is another sign of the growing importance of this technology. However, a significant breakthrough has not yet occurred for two key reasons:

1. Lack of standardization

BPL uses the frequency range from 2 to 40 MHz (in the US up to 80 MHz), in which various shortwave services, government agencies and amateur radio operators operate. It was radio amateurs who launched a campaign against BPL in some European countries and this topic is being actively discussed. International standardization institutes, for example, ETSI, CENELEC, IEEE, in special working groups, are developing a standard regulating the use of BPL in medium and low voltage networks and distribution networks
in buildings and guaranteeing coexistence with other services.

2. Cost and business model

The cost of Powerline infrastructure with modems, interconnection equipment and repeaters is still high compared to, for example, DSL technology. The high cost, on the one hand, is explained by small production volumes, and on the other hand, by the early stage of development of this technology. When using broadband services, BPL technology must be competitive with DSL in both performance and cost.

In terms of business model, the role of utilities in creating value can vary greatly, from selling rights of use to providing full service provider services. The main difference between various models consists of the share of participation of public utilities.

Trends in the development of communication technologies

In public telecommunications networks today, more than 90% of data traffic passes through SDH/SONET. Such fixed-switched circuits are now becoming uneconomical because they remain operational even when not in use. Additionally, market growth has noticeably shifted from voice applications (TDM) to data communications (packet-oriented). The transition from separate mobile and wireline networks, LAN and WAN to a single integrated IP network is carried out in several stages, taking into account existing network. In the first stage, packet-oriented data traffic is transmitted in virtual packets of the existing SDH network. This is called PoS (Packet over SDH) or EoS (Ethernet over SDH) with reduced modularity and therefore lower bandwidth efficiency. The next transition from TDM to IP is offered by today's NG SDH (Next Generation SDH) systems with a multi-service platform that is already optimized for packet-oriented applications GFP (general synchronization procedure), LCAS (link capacity control scheme), RPR (flexible packet rings) and other applications in the SDH environment.

This evolution in communications technology has also impacted the management structure of power grids. Traditionally, communication between control centers and substations for supervisory control and data acquisition systems has been based on serial protocols and dedicated channels that provide fast signal transmission times and are always in a state of readiness. Of course, dedicated circuits do not provide the flexibility required to operate a modern power grid. Therefore, the trend towards using TCP/IP (Transmission Control Protocol/Internet Protocol) has come in handy. The main drivers for switching from serial protocol to IP protocol in supervisory control and data acquisition systems are:

• the proliferation of optical systems provides increased bandwidth and resistance to electrical interference;
• the TCP/IP protocol and related technologies have become the de facto standard for data networks;
• the emergence of standardized technologies that ensure the required quality of functioning of networks with the TCP/IP protocol (QoS quality of service).

These technologies can address technical concerns about reliability and the ability to provide fast response times for supervisory control and data acquisition applications.

This transition to TCP/IP networking makes it possible to integrate supervisory control and data acquisition network management into overall network management.

Configuration changes in this case can be carried out by downloading from the central control unit, instead of time-consuming updating of the firmware of the corresponding substations. Standards for IP-based protocols for telemechanical systems are being developed by the global community and have already been released for substation communications (IEC61850) Figure 10.

Standards for communication between substations and the control center and between the substations themselves are still under development. In parallel, the transition of voice applications from TDM to VoIP, which will significantly simplify cable connections at substations, since all devices and IP telephony use the same local network.

In older power distribution networks, communication connections were rarely installed because the level of automation was low and meter data was rarely collected. The evolution of energy networks in the future will require communication channels at this level. Constantly growing consumption in megacities, scarcity of raw materials, increasing share of renewable energy sources, generation of electricity in close proximity to the consumer (“distributed generation”) and reliable distribution of electricity with low losses these are the main factors determining the management of tomorrow’s networks. Communication in ASKUE in the future will be used not only for reading consumption data, but also as a two-way communication channel for flexible formation of tariffs, connecting gas, water and heat supply systems, transferring bills and providing additional services, For example, burglar alarm. Widespread provision of Ethernet connectivity and sufficient bandwidth from control to consumer are essential to manage the operation of future networks.

Conclusion

Integrating telecommunications services across power grids will require tight integration of different technologies. In one power network, depending on the topology and requirements, several types of communication will be used.

HF communication systems over power lines can be a solution to these problems. The development of IP protocol support, especially for HF over high voltage power lines, provides significant increases in throughput. Siemens is also contributing to this development: technologies are already being developed to increase the bandwidth and therefore the transmission speed to 256 kbit/s. BPL technology is an excellent platform to enable communications in future medium and low voltage networks to provide all new services to the consumer. Future BPL systems from Siemens offer a single hardware platform for narrowband (CENELEC) and broadband applications. HF communications will have a strong place in next-generation energy networks and will be an ideal complement to optical and wireless broadband systems.

Siemens is following this trend and is one of the few global manufacturers in both RF and communications networks to offer a single, integrated solution.

Literature:

1. Energie Spektrum, 04/2005: S. Schlattmann, R. Stoklasek; Digital-Revival von PowerLine.
2. PEI, 01/2004: S. Green; Communication Innovation. Asian Electricity 02/2004: Powerline Carrier for HV Network.
3. Middle East Electricity, Feb. 2003: J. Buerger: Transmission Possible.
4. Die Welt, April 2001; J. Buerger: Daten vom Netz ubers Netz.
5. VDI Nachrichten 41; October; 2000 M. Wohlgenannt: Stromnetz ubertrugt Daten zur eigenen Steuerung. Elektrie Berlin 54 (2000) 5-6; J. Buerger, G. Kling, S. Schlattmann: Power Line Communication-Datenubertragung auf dem Stromverteilnetz.
6. EV Report, Marz 2000: J. Buerger, G. Kling, S. Schlattmann: Kommunikationsruckrat fur Verteilnetze.
7. ETZ 5/2000; G. Kling: Power Line Communication Technik fur den deregulierten Markt.

Karl Dietrich, Siemens AG,
Department of Electricity Transmission and Distribution PTD,
division EA4 CS.
Translation: E. A. MALYUTIN.

High-frequency communication equipment with digital signal processing (DSP) was developed by RADIS Ltd., Zelenograd (Moscow) in accordance with the technical specifications approved by the Central Control Department of the UES of Russia*. AVC was accepted and recommended for production by the interdepartmental commission of JSC FGC UES in July 2003, and has a certificate from the State Standard of Russia. The equipment has been manufactured by “RADIS Ltd” since 2004.
* Currently OJSC SO-TsDU UES.

Purpose and capabilities

AVC is designed to organize 1, 2, 3 or 4 channels of telephone communication, telemechanical information and data transmission over 35-500 kV power lines between the control center of a district or enterprise of electrical networks and substations or any objects necessary for dispatch and technological control in power systems .

In each channel, telephone communication can be organized with the possibility of transmitting telemechanical information in the supra-tone spectrum using built-in or external modems, or transmitting data using a built-in or external user modem.

ABC modifications

Combined option

terminal АВЦ-С

Execution

ADC widely uses methods and means of digital signal processing, which ensures accuracy, stability, manufacturability and high reliability of the equipment. The AM OBP modulator/demodulator, transmultiplexer, adaptive equalizers, built-in telemechanics modems and service control signal modems included in the ADC are made using signal processors, FPGAs and microcontrollers, and the telephone automation and control unit are implemented on the basis of microcontrollers. The STF/CF519C modem from Analyst is used as a built-in modem for data transmission in the channel.

Specifications

Number of channels	4, 3, 2 or 1
Operating frequency range	36-1000 kHz
Nominal frequency band of one direction of transmission (reception):
- for single-channel	4 kHz
- for two-channel	8 kHz
- for three-channel	12 kHz
	16 kHz
Minimum frequency separation between the edges of the nominal transmit and receive bands:
- for one- and two-channel	8 kHz (in the range up to 500 kHz)
- for three-channel	12 kHz (in the range up to 500 kHz)
- for four-channel equipment	16 kHz (in the range up to 500 kHz)
- one-, two-, three and four-channel equipment	16 kHz (in the range from 500 to 1000 kHz)
Maximum peak transmitter power	40 W
Receiver sensitivity	-25 dBm
Selectivity of the receiving path	meets the requirements of IEC 495
AGC adjustment range in the receiver	40 dB
Number of built-in telemechanics modems (speed 200, 600 baud) in each channel
- at a speed of 200 Baud	2
- at a speed of 600 Baud	1
Number of connected external telemechanics modems in each channel	No more than 2
Number of built-in data modems (speed up to 24.4 kbit/s)	Up to 4
Number of connected external modems for data transfer	Up to 4
Nominal impedance for RF output
- unbalanced	75 Ohm
- balanced	150 Ohm
Operating temperature range	0…+45°С
Nutrition	220 V, 50 Hz

Note: with a balanced output, the midpoint can be connected to ground directly or through a 75 Ohm 10W resistor.

Short description

The AVTs-LF terminal is installed at the control center, and the AVTs-HF terminal is installed at the reference or hub substation. Communication between them is carried out via two telephone pairs. Frequency bands occupied by each communication channel:

The overlapped attenuation between the AVC-LF and AVC-HF terminals is no more than 20 dB at the maximum channel frequency (characteristic impedance of the communication line is 150 Ohms).

The effective bandwidth of each channel in the ABC is 0.3-3.4 kHz, and it can be used:

Telemechanics signals are transmitted using built-in modems (two at a speed of 200 Baud, average frequencies 2.72 and 3.22 kHz or one at a speed of 600 Baud, average frequency 3 kHz) or external user modems.
Data transmission is carried out using the built-in STF/CF519C modem (depending on the line parameters, the speed can reach 24.4 kbit/s) or an external user modem. This makes it possible to organize up to 4 channels of inter-machine exchange.
The AVTs-LF (AVTs-S) reception path provides semi-automatic correction of the frequency response of the residual attenuation of each channel.
Each AVC telephone channel has the ability to turn on a compander.

Telephone cell	AVTs-NC (AVTs-S) contains built-in devices for automatic connection of subscribers (automatic telephones), which allow the connection of:
If the channel is used for data transmission, then the telephone automation cell is replaced by a cell of built-in STF/CF519C modems.	Modem cell STF/CF519C

AVTs-LF and AVTs-S have a control unit that, using a service modem for each channel (transmission rate 100 Baud, average frequency 3.6 kHz), transmits commands and continuously monitors the presence of communication between local and remote terminals. If the connection is lost, an audible signal is issued and the contacts of the external alarm relay are closed. In the non-volatile memory of the unit, an event log is kept (switching on/off and readiness of the equipment, “disappearance” of the communication channel, etc.) with 512 entries.

The necessary AVC modes are set using a remote control panel or an external computer connected via an RS-232 interface to the control unit. The remote control allows you to take a level diagram and characteristics of the residual attenuation of the channel, perform the necessary correction of the frequency response and evaluate the level of characteristic distortions of the built-in telemechanics modems.

The operating frequency of the equipment can be adjusted by the user within one of the subranges: 36-125, 125-500 and 500-1000 kHz. Tuning step - 1 kHz .

Schemes for organizing communication channels

In addition to the direct communication channel (“point-to-point”) between half-sets of the ABC, more complex schemes for organizing communication channels (“star” type) are possible. Thus, a two-channel dispatch semi-set allows you to organize communication with two single-channel semi-sets installed at controlled points, and a four-channel one - with two two-channel or four single-channel semi-sets.

Other similar configurations of communication channels are possible. With the help of an additional AVC-HF terminal, the equipment provides the organization of four-wire re-reception without selecting channels.

In addition, the following options may be provided:

	Using only the AVC-HF terminal, work is organized in conjunction with an external modem having a band of 4, 8, 12 or 16 kHz in the nominal frequency range from 0 to 80 kHz, which allows you to create digital high-frequency communication complexes. For example, on the basis of the AVTs-HF terminal and M-ASP-PG-LEP modems from Zelaks, it is possible to organize communication with a data transfer rate of up to 80 kbit/s in a 12 kHz band and up to 24 kbit/s in a 4 kHz band.
	In the nominal band of 16 kHz, two channels are organized in the ABC, namely the 1st with a band of 4 kHz for telephone communication and the 2nd with a 12 kHz bandwidth for data transmission by user equipment.
	The work of up to four single-channel subscriber semi-sets of ABC is organized at controlled points with a single-channel dispatch semi-set of ABC. With a telephone channel bandwidth of 0.3-2.4 kHz, the equipment will provide one duplex communication channel for the exchange of telemechanical information at a speed of 100 baud between the control room and each half-set at the controlled point. When using external modems with speeds greater than 100 Baud, only cyclic or sporadic exchange of telemechanical information is possible between the dispatch and subscriber half-sets.

Weight and size parameters of the equipment

Name	Depth, mm		Height, mm

Installation

The equipment can be installed on a rack (up to several vertical rows), in a 19” rack or mounted on a wall. All cables for external connections are connected from the front. An intermediate terminal block for connecting cables is available upon request.

Environmental conditions

AVC is designed for continuous round-the-clock operation in stationary conditions, in enclosed spaces without permanent maintenance personnel at temperatures from 0 to +45C O and relative humidity up to 85%. The functionality of the equipment is maintained at ambient temperatures down to -25C.