Ferroresonance Characteristics on Capacitive Voltage Transformer Under Lightning Impulse Voltage

Abstract

Nowadays, more papers explain about the occurrence of ferroresonance due to the switching operation. Indeed, the switching operation is more possible to occurr on system respect to other transient disturbances, such as lightning stroke. However, lightning stroke which is always characterized by a high impulse current is also able to initiate the ferroresonance on the system. In this paper, the effect of ferroresonance due to the lightning stroke on capacitive voltage transformer (CVT) is simulated and investigated. The ferroresonance causes an overvoltage as well as on overcurrent on CVT. ATP/EMTP is utilized to simulate and analyze the ferroresonace phenomena. In this study, Heidler’s lightning model is used to describe the lightning condition on the system. Lightning impulse parameters such as its amplitude and duration, including its front time (ts) and tail time (tr) are varied. The effect of these lightning parameters on peak voltage and peak current on the primary side of CVT is investigated. The simulation results show that the peak voltage increases to about 267.5% of its normal peak voltage while peak current increases up to about 266.1% of its normal current. These peak values increase linearly with the amplitude and they increase non-linearly with the duration of the lightning impulse. However, the front time almost does not affect the peak values of voltage and current. Therefore, it can be concluded that lightning impulse characteristics affect the occurrence of ferroresonance on CVT.