Incorporation of HVDC and SVC models in the Northern State Power Co. (NSP) network; for on-line implementation of direct transient stability assessment

In this paper, the authors discuss the incorporation of the 4 DC power systems and 2 SVCs in the Northern State Power Company (NSP) network (USA) for online implementation of direct power system transient stability assessment. The DC and SVC models used are more complicated than those used in the existing AC-DC-SVC transient energy function (TEF) literature. In this new approach, the commutation failure of the HVDC is also considered. It is necessary to use these complicated DC and SVC models because in the NSP network they are located in an area where the transient stability is of great concern. The DC and SVC systems are treated as part of the AC network and their effect on the transient energy function is included. The effect of DC and SVC on the calculation of the potential energy is reflected in the AC network solution. The equivalent models and the proposed procedure developed is tested on a NSP equivalent network of 273 generators and 2217 buses. The result obtained are in excellent agreement with those obtained by time domain simulation using EPRI ETMSP V3.0