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Limit the overvoltage with Reactors and Series Reactors
Reactors and Series Reactors are used widely in AC networks to limit the overvoltage or to limit the shortcut current. With more high-voltage overhead lines for long transmission distance and increasing network capacity, Reactors and Series Reactors play an important role in the modern network system.
For extra-high-voltage (EHV) transmission lines, due to the long distance, the space between the overhead line and the ground naturally forms a capacitor parallel to the transmission line, which causes an increase of voltage along the distance. Depending on the distance, the profile of the line and the power being transmitted, a Reactor is necessary either at the line terminals or in the middle. The advanced design and production technology will ensure the product has low loss and low noise level.
When the network becomes larger, sometimes the short-circuit current on a transmission line will exceed the short-circuit current rating of the equipment. Upgrading of system voltage, upgrading of equipment rating or employing high-impedance transformers are far more expensive than installing oil-immersed Series Reactors in the line.
Distributed electricity generation from wind and solar energy is enjoying rapid growth in the Western world. However, they are extremely volatile and thus produce load variations at all voltage levels. In addition, the distribution of the energy generated by large power plants and offshore wind parks to centers of consumption located some distance away places new demands on the power supply grids. Variable shunt reactors can play an important role in overcoming both of these challenges.
Siemens variable shunt reactors counteract the undesirable consequences of this development in the following ways:
Siemens can provide flexible solutions that react quickly and reliably to abruptly changing network conditions.
For the Electricity Authority of Cyprus the Siemens Transformer plant in Nuremberg manufactured two units
with 75-28 MVAr, 155kV.
Further information to be found in the case study about this project:
Brochure: Shunt and series reactors for medium- and high-voltage grids