The Simulation Model of a Power Inverter with a Voltage Support Mechanism at the Point of Common Connection to the Grid

The article addresses the development of a simulation model of a power inverter with a voltage support mechanism at the point of common connection to the grid under the conditions of external disturbances and subsequent simulation in the MATLAB Simulink software package. When developing the model, the technical limitations imposed on the power inverters operating as part of solar power plants and wind farms were taken into account. The parameters of the PQ-diagram, LVRT and Q(U)-characteristics are selected in accordance with the current recommendations of the Commission for Operational and Technological Coordination of the Joint Operation of Power Systems of the CIS and Baltic Countries (COTC). The incorporation of these limitations opened the possibility to achieve more correct and reliable results of the studies aimed at clarifying the effect the voltage support mechanism has on the electric power mode operation parameters. A system test model has been developed, which represents a power plant based on renewable energy sources (RES) with a total installed capacity of 25 MW, as well as an adjacent grid section. The effect the voltage support mechanism has on the electric power mode operation parameters, as well as on the reliability of parallel operation of power inverters with the electric power system in the event of external disturbances in the network, has been studied. The use of power inverters with a voltage support mechanism helps reduce the voltage deviations from the nominal values at the inverter terminals, as well as at the point of connection to the grid. The application of the developed mechanism is one of the ways to ensure the required electric power quality indicators. In case of large disturbances in the external grid, the voltage support mechanism makes it possible to retain the possibility of parallel operation of power inverters with the grid. This helps improve the economic performance indicators of operation for the owners of RES-based power generating facilities.