GK Dürnrohr

The GK Duernrohr ( = DC short coupling Duernrohr ) was an HVDC close coupling to the west of substation Duernrohr which served the energy exchange between Austria and Czechoslovakia from 1983 to 1996. The GK Duernrohr had a nominal transmission capacity of 550 MW. The nominal value of the direct voltage in the intermediate circuit was 145 kV. The transmission loss at maximum power were 1.4 %.

Building and Planning

The planning for this facility was started in 1975. This was preceded by a contract between Austria and the People's Republic of Poland on a lead through the territory of Czechoslovakia line was to exchange electrical energy. The end of 1980, work began to build the plant. In early 1982, the construction works were completed to the extent that could be started with the assembly of the components. As of mid- 1983, the commissioning of the plant began. From mid-June 1983, the experiment of energy exchange with Czechoslovakia. The official operating recording was made on September 1, 1983.

Converter Hall

The power converter of the system is housed in a 29.8 m long, 15.4 m wide and 13.8 m high reinforced concrete hall, which has on both longitudinal sides two bays for the converter transformers. For the purpose of fire protection are the walls of the converter hall, which have a thickness of 20 cm, with a stone wool insulation. The entire hall is covered with galvanized sheet metal, which serves as a shield and weather protection.

The hall is built. In the cellar, air conditioning, water cooling system for the power converter and the water treatment plant are housed. At the western end of the narrow side of the inverter hall the company building is only through a fire wall of these separately been built, in which an auxiliary control room, battery and rectifier rooms, testing and storage premises and ventilation equipment for air condition. A non- openable triple glazed window in the bulkhead for the converter hall offers a view on the converter valves. At the eastern end of the narrow side of the inverter hall is the smoothing reactor.

Transformers

On both sides of the converter per two three-phase power transformers come with each 335 MVA rated power and a nominal ratio of 400: 63 for use. All converter transformers, the primary windings are connected in a star, while on either side of the power converter has a transformer in the constellation and the other delta-connected secondary windings. The transformers in which the primary and secondary windings are connected in star, are structurally identical to each other, as are the transformers connected in a star high voltage and the triangle -connected secondary winding. However, the transformers connected in star secondary winding are not identical to those with the triangle -connected secondary winding.

Converter

The executed in twelve-pulse converter circuit used for each branch rectifier 44 connected in series thyristors with a peak reverse voltage of 4.2 kV and a rated maximum continuous current of 3790 A. In total there were installed in the plant in 1056 thyristors. They were having a silicon disc diameter of 100 mm at the time of installation of the system thyristors largest in the world.

Each converter consists of three Thyristortürmen which are all in the converter hall. Each Thyristorturm contains a complete twelve -pulse branch of the converter. In these Thyristortürmen be used for any valve function of four series-connected thyristor modules, which are arranged in two floors. Between the thyristor one floor (ie the respective first and second or the third and fourth ) is an iron ballast. In parallel with the thyristor of a floor is a capacitor. Parallel to each valve function there is a surge in the form of a varistor.

Each thyristor consists of eleven series-connected thyristors, which in each case a series circuit comprising a capacitor and a resistor is connected in parallel. From this circuit, the power for the electronic control is obtained. Since the thyristors and the control electronics are located on high voltage potential, the transfer of the ignition pulses via fiber optic cable. A second fiber optic cable enables the transmission of data to the control electronics of the thyristor to ground. As a control is a programmable control of the system SIMATIC S5 used.

The thyristors and connected with them in series reactors are cooled with deionized water, which is located in a closed circuit. The resulting heat is transferred to a second cycle in which there is staggered with glycol water. About evaporative cooler with fans the warmth of this circuit is discharged to the environment. For the purpose of maintenance, the corresponding modules are replaced with intact modules and transported to the repair and testing room. Light has a telescopic lift and a crane in the converter hall.

Smoothing reactor

, Erected on the east side of the converter hall smoothing reactor is a built by ELIN oil-cooled iron ballast with 85 mH inductance.

Harmonic Filters

As a harmonic filters are on both sides of the system of four series resonant circuits are used. Each one of the filters consists of a air-core inductor of 41 mH, which is connected in parallel with a resistor 615 Ω. In series with this combination is a capacitor with two uF, which establishes the connection to the high voltage line. The other filter, which is on both sides of the converter also easily available, also consists of a capacitor with 2 uF, which is connected to a parallel circuit of a resistor with 615 Ω and an air choke with 29 mH in series.

For the purpose of reactive power compensation, there is also parallel to the outputs of a capacitor bank. Their value is 2 uF at the output to the Czech Republic and 1uF for the current output to Austria.

Static var compensator

There is also a static var compensator, which remained in operation and after closure of the HVDC -to-back on the grounds of the facility. It consists of two groups of single-phase reactors, which are supplied through an on- the 380-kV-/220-kV-Transformatoren tertiary winding 30 kV, and can provide a maximum reactive power 200 MVARs. The first throttle group went in 1982, the second 1986.

Since it would come after the completion of GK Vienna-Southeast to a huge spike in the network when a load shedding would have occurred during the simultanenen current exports on GK Duernrohr and GK Vienna-Southeast, 1991-1992 was one on the site of GK Duernrohr taken thyristor controlled reactive power compensator in operation, the s can provide a reactive power of 580 MVAr at a voltage of 400 kV, a duration of 150 MVAr reactive power and for 0.3. This plant is still in operation today.

Power line to the Czech Republic

The 102 km long power line after Slavětice in the Czech Republic is continuous as an overhead line, which are designed for masts for the addition of two circuits shifted. By 2008, only a 380 kV circuit was installed.

In the Czech Republic the two- plane array ( Danube mast picture), in Austria, the three-level arrangement ( tons Mast picture) the conductors will be used. The line crosses the border at Kleinhaugsdorf.

Closure

After the sync circuit of the power grids Western and Eastern Europe on 17 October 1995, the installation continued until 31 October 1996 as Austria, unlike Germany at that time had no powerful 380 - kV network. Only after some power plants with a powerful means for controlling the power frequency were fitted in Poland, was to dispense with the operation of the plant. The high voltage switching devices were used in the substations Vienna Southeast and Southern Burgenland, as are the transformers that had to be rewound on a secondary voltage of 110 kV, however.

By eliminating the close-coupling, the maximum transferable power increased on the line connecting Slavětice after Duernrohr to 1386 MVA. By sharing some coils of the carrier frequency systems, the transmission power at 1481 MVA was increased. Carried out in 2008 installation of a second 380 kV circuit for which the poles of the line Duernrohr - Slavětice are designed, has doubled this value to 2962 MVA.

Since the proposed sale of the plant did not come to Eastern Europe to build a HVDC close coupling between the power supply in Eastern Europe and the former Soviet Union, among others because of their age to pass, the remaining components of the system were dismantled and disposed of in 2007. The converter hall is today used for operating purposes of the former operator, Verbund AG.

Swell

• ÖZE, Austrian Journal of the electricity industry. Pp. 257 to 330