Variable shunt reactors at high voltage of 400 kV are a novelty in Slovenia, but there are similar solutions to expect in the future. In this diploma thesis we are focusing on a variable shunt reactor installed in Divača, which is part of a larger project called SINCRO.GRID established by Slovenia and Croatia. Its main purpose is to harmonize the voltage conditions with the operating standards of the 400 kV network. This way it is possible to increase the transmission capacity of the network, improve the quality of voltage and consequently extend the service life of the associated equipment. Project is currently still underway, but its positive effects are already perceived by transmission system operators.
In general, there is a trend of electricity transmission through underground cable lines and the reason for that is among other things also public unacceptability of overhead cable lines. Leaving aside the high price of underground cable lines, high voltage cable lines represent a strong source of reactive power for transmission network. But it could result in unacceptable (too high) voltage profile if appropriate measures are not taken. The most basic measure for voltage regulation is variable shunt reactor since it can continuously compensate reactive power in the transmission network.
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