Abstract:

For the long-distance UHV transmission system, its transmission capacity is mainly restricted by small disturbance stability. UHV transmission system with large-scale power supply has characteristics of long transfer distance and huge transfer power, whose transmission capacity has always been a concern. Based on the characteristics of sending system, the receiving system was equivalent to single machine system of load, and the equivalent damping coefficient of the system was deduced in detail. The influence of parameters of generator, network on the system’s equivalent damping coefficient was discussed, from two aspects of generator and system network. The simulation results of UHV large power transmission system in PSASP indicate that: the parameters of generator or network can influence damping coefficient and thus affect the UHV system transmission capacity. The results also verify the correctness of the theoretical derivation； can provide theoretical basis and policy for the improvement of UHV transmission capacity, which is valuable to engineering application.

Key words: UHV transmission system, transmission capacity, small signal stability, parameters of generator and network, equivalent damping coefficient