Analyzing and tuning the time scale characteristics of the short circuit current of the synchronous condenser in the UHVDC inverter station of the heavy load center

Abstract

The synchronous condenser with fast control has been installed in UHVDC inverter station recently to remain voltage and avoid continuous commutation failures (CCFs) during short circuit faults. However, the synchronous condenser can produce excess short circuit current (SCC) which may cause relay protection failure if the total SSC exceeds the interrupting capacity. It seems that there is a contradiction between the ability to avoid CCFs and the effect of the excess SSC for the synchronous condenser in the heavy load center with high level SCC. In order to solve the contradiction, the time scale characteristics of the synchronous condensers SCC are analyzed and tuned in this paper. Firstly, the synchronous condensers SCC is formulated in different time scales related to CCFs and relay protection. Then the relationship between the SCC and manufacture parameters, initial conditions together with excitation control of the synchronous condenser is investigated. Thus the time scale characteristics of the synchronous condensers SCC are discovered. And then a tuning strategy of the time scale characteristics of the SCC is proposed to ensure the ability to avoid CCFs as well as reduce the adverse effect on relay protection. Finally, simulation study is performed to validate the work.