ATP analysis of TRV applied to the medium voltage circuit of solar and onshore wind power plants

Abstract

Abstract The increase in the deployment of solar and onshore power plants, which collector circuit is of medium voltage, has created a demand for new techniques of analysis for this kind of circuit, especially in regard to the TRV-Transient Recovery Voltage and consequent circuit breaker rating. In this case, despite some similarities to usual power distribution systems that goes beyond the same voltage level, the so available standards for circuit breaker rating do need corrections in view of contemplating its deployment in these two types of power plants. Reasons for this rely on the intrinsic topological characteristics of their medium-voltage circuits. Based on this concern, this work presents a computational analysis of the influence of the topological factors that make the TRV to become critically severe, in these two types of power plants, not considering offshore plants. The analysis is performed through a series of ATP simulations for the case of an ungrounded three-phase short-circuit by modelling the power generator as being an ideal one, with a conservative approach. As the main result, it is shown that feeder cable length appears as one of the key factors to be considered. Moreover, consequences of connection of harmonic filter and power factor correcting reactor required by regulatory agencies are also analysed and shown as being equally critical.