Protection and control of two phase shifting transformers in the Netherlands

The phase shifting transformer (PST) is designed as a symmetrical phase shifting transformer so the exciting transformer is connected to the middle point of the series transformer. Both transformers consist of three identical single phase transformer units. For each phase both the series transformer and the exciting transformer are located in a single tank. The secondary windings of the series transformer are connected in a delta configuration. The transformer units are inter- connected with single phase XLPE cables. The neutral of the secondary windings is connected to earth with a reactor to reduce the short circuit currents. The primary windings of the transformer are protected by two redundant biased differential protections. The current transformers are located in the source and load connection of the series transformer and in the neutral connection of the exciting transformer.