Influence of Distributed PV Systems on Voltage in Distribution Network and Countermeasure of Voltage Beyond Limits

With the large scale distributed photovoltaic (PV) systems connected to the grid, the voltage problem of distribution network becomes one of the biggest challenges in the development of distributed PV. Taking the radial distribution network as research object, the influences of connecting single PV system and multi PV systems to distribution network on voltage of distribution network are analyzed respectively. The factors that affect the distribution network voltage distribution are discussed, including the access capacity, access location, load size, operation mode and access mode. The correctness of above-mentioned analysis is verified by America PG&E69 nodes system, and the obtained conclusions are as follows: the PV systems increase the line voltage and the voltage variation is directly related to the distribution of loads and the output of PV systems. Meanwhile, the countermeasure of voltage beyond limits in distribution network is put forward. The countermeasure can make full use of the residual capacity of the inverter to absorb reactive power, and solves effectively the problem of voltage beyond limits caused by distributed PV systems connected to the grid.