Application effect evaluation of demonstration project of thyristor-controlled phase shifting transformer in 500kV grid

The considerably uneven distribution of power flow on 500kV Anhui-Jiangsu cross province interface during peak hours may contribute to overload conditions in case of outages on one of the four transmission lines of this interface. Export of electric power from Anhui province through this inter face to Yangze Delta load center is restricted to 4800MW. Installation of thyristor-controlled phase shifting transformer (TCPST) on each of the 500kV cross province transmission lines from Dangtu substation to Huifengshan substation is reviewed to be effective solution for interface power flow control under various possible grid operation conditions. This paper evaluates the application effect of the demonstration project, which involves power flow control impact on the interface and neighboring system, short circuit current limiting effect with respect to the impedance of TCPST under varying phase shifting angle as well as system stability performance related issues. The evaluation is expected to provide theoretic basis for the implementation of the demonstration project.