Fast frequency response technology of photovoltaic power plant based on equivalent modelling

Abstract

With the centralized access of large capacity and high proportion of new energy to the power grid, the power structure has undergone great changes, and the fast frequency response resources available to the power grid have gradually decreased. If high‐power DC blocking occurs, it will pose a serious threat to the frequency security of the power grid, and the frequency regulation pressure of the power grid and the risk of safe operation will continue to increase. To this end, a fast frequency response technology for photovoltaic power plants based on equivalent modelling is proposed. According to the principle of equivalent modelling, the equivalent model of a single unit of photovoltaic power station is established through the parameters of photovoltaic array, photovoltaic inverter, unit transformer, unit transformer and collector line. According to the fast frequency response performance requirements of photovoltaic power plants, combined with the characteristics of photovoltaic power plants, a feasible scheme for fast frequency response of photovoltaic power plants is introduced. The case study on the implementation of fast frequency response project in photovoltaic power station shows that according to the order and type of AGC command and fast frequency response command, photovoltaic power station has conducted command superposition tests under 50 ±0.2 Hz and 50 ±0.09 Hz disturbance amplitudes respectively, and the results are qualified. The integration of automatic generation control/automatic voltage control (AGC/AVC) and fast frequency response function of photovoltaic power station is realized by using relevant technologies, so that the photovoltaic power station can actively support the grid frequency and voltage.