Reactive voltage control strategy of distribution network considering the reliability of photovoltaic power supply

Photovoltaic power actively regulates the reactive power of the active distribution network, leading to the increase of output current of the photovoltaic inverter. Consequently, the temperature rise significantly impacts the maximum junction temperature of the Insulated Gate Bipolar Transistor (IGBT), leading to fluctuations in the junction temperature. To realize the active support of the reactive power of the photovoltaic power supply and ensure its reliable operation, a reactive voltage control strategy of the active distribution network considering the reliability of the photovoltaic power supply is proposed. Considering the reactive power support capability of the distributed photovoltaic power, a multi-objective reactive power optimization model for active distribution networks is established based on IGBT maximum junction temperature, distribution network losses, and photovoltaic active power reduction. The effectiveness of the proposed strategy in enhancing the minimum lifetime, average lifetime, and reliability of photovoltaic power sources is verified using the IEEE 33-node standard distribution system. The results show that under the strategy proposed in this paper, the average junction temperature and junction temperature fluctuation of IGBT are effectively reduced, and the minimum lifetime and average lifetime of all IGBTs are increased by 8 years and 4 years respectively.