Controlling Ferroresonance in Voltage Transformer Including Nonlinear Core Losses by Considering Circuit Breaker Shunt Resistance

摘要

Ferroresonance or nonlinear resonance is a complex electrical phenomenon, which may cause over voltages and over currents in the electrical power system which endangers the system reliability and continuous safe operating. This paper studies the effect of circuit breaker shunt resistance on the control of chaotic ferroresonance in a voltage transformer while the core losses of the VT core is highly nonlinear. It is expected that this resistance generally can cause ferroresonance 'dropout'. For confirmation this aspect simulation has been done on a one phase voltage transformer rated 100VA, 275kV. The magnetization characteristic of the transformer is modeled by a single-value two-term polynomial with q=7. The simulation results reveal that considering the shunt resistance on the circuit breaker in the case of nonlinear core losses, exhibits a great mitigating effect on ferroresonance over voltages. Significant effect on the onset of chaos, the range of parameter values that may lead to chaos along with ferroresonance over voltages has been obtained and presented.