Effects of variable solar irradiance on the reactive power compensation for large solar farm

Dish-Stirling systems are a form of concentrating solar power (CSP) emerging as an efficient and reliable source of renewable energy. Various technical hurdles are involved in the grid interconnection of dish-Stirling systems, particularly with issues related to power factor correction, low voltage ride-through capability, and reactive power planning. While there are no grid-interconnection requirements specific to dish-Stirling technology, the requirements currently established for wind farms are used as a starting point due to the similar design and operating characteristics between wind farms and dish-Stirling solar farms. A dish-Stirling solar farm requires external reactive power compensation to meet the power factor requirements presently set for wind farms. The following paper provides a brief overview of dish-Stirling technology, along with an analysis of methods for meeting power factor grid interconnection requirements and maintaining necessary voltage levels under varying irradiance conditions due to cloud cover. Simulation results for voltage and power factor of the solar farm are provided for both steady state and cloud transient conditions within a 12-bus network.