Study of Nonlinear Model of Shunt Reactor in 1000kV AC Transmission System

Modeling of accurate nonlinear shunt reactor is basis of harmonic analysis of 1000kV AC transmission system. Based on the electromagnetic relations of single-phase shunt reactor and the effect of iron core nonlinearity, a new model of single-phase shunt reactor used for harmonic analysis and computer simulation is presented. It presented shunt reactor by a simple equivalent circuit consisting of an impedance representing the leakage flux losses in series with a parallel combination of a nonlinear inductance (accounting for the saturation of the iron core) and a nonlinear resistance (accounting for the iron loss). The nonlinear impedance is calculated by the and curves which had been used for modeling of transformer excitation impedance. The result of simulation in PSCAD/EMTDC using the parameters of shunt reactor in China's UHV AC Pilot Project have proved that this model accurately reflect the nonlinear characteristics of shunt reactor, which is the prerequisite to complete the simulation model of UHV AC transmission system and analyze the harmonic characteristic of the system.