Influence of Out-of-Phase of Synchronous Generators on Short-Circuit Currents in Power Systems

Abstract

The calculation of short-circuit currents (SC) in electric power systems (EPS) is performed with a number of assumptions. One of the assumptions is the supposition of in-phase operation of all EPS generators in the process of the previous SC mode and in the process of SC. At present time, due to the exacerbations of the problem of ensuring compliance, installed in the EPS of electrical equipment with continuously increasing levels of SC currents, the requirements to the accuracy of calculation SC currents are toughened. The EMTP-RV (Powersys) program was used to analyze the influence of out-of-phase SG on the SC current. The calculation of SC was performed for a generator operating in parallel with the electric power system. As initial data, the parameters of synchronous hydro generators of the electric power system of the Republic of Tajikistan were used. An estimate is obtained from the influence of out-of-phase synchronous generators on the magnitude of the total and the periodic component of the SC current. It is established that neglecting out-of-phase generators can lead to an overestimation of the calculated values of the SC current by more than 10%.