Approach and Structure of Stabilizing Control System Preventing an Extension of Loss of Synchronism

Abstract

Recently large capacity power stations have been built far from load center with long distance transmission lines. Therefore, if a fault occurs at the line, generators in the large capacity power station may lose synchronism from the remaining generators ⁽¹⁾⁽³⁾. To prevent an extension of loss of synchronism to other generators, fast shedding of some generators is effective measures.
Following methods were proposed so far. One⁽³⁾ is based on energy function approach. The other⁽²⁾ estimates and predicts the relative swing among generators using data measured on-line at each generator and sheds some generators for stabilization. Therefore this method requires a large communication network for an exchange of data between power stations. This paper presents new stabilizing method and newly developed stabilizing control system which does not require a large communication network because it utilizes generator output, voltage and current measured on-line in the vicinity of the large capacity power station. Using these measured data, the system estimates and predicts relative swing between generators in the large capacity power station and the remaining generators. Finally the number of generators to be shed for stabilization is decided and shedding is performed. Configuration and characteristics of the developed stabilizing control system are shown. Validity of this method is confirmed by simulation and testing using an artificial power system.