Design and Analytics of Dynamic Reactive Power Controller for 6 MW Solar Power plant

Conventional electrical power systems are designed for unidirectional power flow from the utility to the consumer. Alternate energy sources such as solar and wind energy systems have led to distributed generation unlike the centralized generation of power. Integration of solar plants with the grid, leads to bidirectional flow of power, which disturbs the voltage level at the point of common coupling. Reactive power management is an essential part of how voltage levels are controlled in the electric power system. However, the reactive power requirements of the power system vary with respect to time as load levels and generation patterns change with respect to time leading to the requirement of dynamic compensation of reactive power. The objective of the project is to compensate the net reactive power requirement of a 6 MW solar photovoltaic plant by generating the reactive power from the inverter. Usually the source of the reactive power consumption in PV plant arises from the inverter transformer, power transformer and auxiliary electrical equipment installed in the PV power plant. By supplying the reactive power requirement of the photovoltaic plant from the inverter, net reactive energy import and export at the point of common coupling is close to zero. This achieves unity power factor at the point of integration of the plant with the grid. This is achieved by changing the reactive power dynamically at the inverter terminals, which in turn will reduce the reactive power at the grid as zero. A PID controller is used to make the PCC reactive power to zero by dynamically changing the reactive power generation from the inverter. A MATLAB Simulink model of solar plant is developed and reactive power at the point of common coupling is reduced close to zero dynamically.