A Ferroresonance Study of a 240 MW Solar PV Project

摘要

Special system studies are needed to assess the different preliminary designs of solar photovoltaic (PV) projects. One of these is a ferroresonance study. The main purpose of a ferroresonance study is to investigate whether the voltage within the project can reach damaging levels under steady state operation. Ferroresonance can become a concern for solar PV project owners due to the distributed nature of shunt cable capacitance in the collector system. This distributed shunt capacitance can interact with the inductance of the main power transformers and the instrument transformers causing the voltage within the project to reach dangerous levels. To perform a ferroresonance study for a large 240 MW solar PV farm, a detailed electromagnetic transient (EMT) model of the project has to be built. A detailed EMT model will have a large number of inverters and thus the run time of the model becomes prohibitive even for a single scenario. In this paper, we simplify the EMT model focusing only on the components that need to be modeled for the purpose of the ferroresonance study thus reducing the run time of the EMT model. Various scenarios corresponding to different operation modes of the project have been simulated. Simulation results shows that the project is not susceptible to ferroresonance except for unusual operating modes during energization and at night when the inverters are not producing any power output.