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Ferroresonance is a non-conventional electrical phenomenon which may cause overvoltages in the electrical power system endangers the system reliability. This paper studies the effect of circuit breaker shunt resistance, Metal Oxide Surge Arrester (MOSA) and neutral earth resistance on controlling chaotic ferroresonance in a potential transformer while transformer core losses is modeled as a nonlinear resistance which hysteresis and eddy current losses are included. It is expected that neutral earth resistance can control ferroresonance better than MOSA and circuit breaker air gap resistance. For confirmation this aspect, simulation has been done on a one phase potential transformer rated 100VA, 275kV. Simulation results show that considering shunt resistance on the circuit breaker and MOSA in parallel to the transformer, exhibits a great mitigating effect on ferroresonance oscillations, but these resistances cannot control these phenomena for wide variation of the power system parameters. By applying neutral earth resistance to the system grounding, ferroresonance is controlled and its amplitude has been damped for all parameters values. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of linear and nonlinear core losses on the onset of chaotic ferroresonance and duration of transient chaos in an autotransformer and control of these phenomena by applying neutral earth resistance to the system grounding. The magnetization characteristic of the transformer is modeled by a single-value two-term polynomial. The nonlinear core loss is modeled by a third order power series in voltage with nonlinearities in core loss included, four effects are clear: (i) onset of chaos at larger values of open phase voltage, (ii) shorter duration of transient chaos,(iii) less susceptibility to 'jump' phenomena and (iv) effect of neutral resistance on controlling of ferroresonance phenomena. It is also shown that nonlinear core losses also can cause ferroresonance drop out. [ABSTRACT FROM AUTHOR]

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. The ability to predict or confirm ferroresonance depends primarily on the accuracy of the transformer model used by the computer simulation. An overview of available literature and contributors to this area is provided. This paper studies the effect of circuit breaker shunt resistance on the controlling chaotic ferroresonance in a voltage transformer while the core losses of the voltage transformer core are 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. [ABSTRACT FROM AUTHOR]