Typical Impact Of Distributed Small Hydropower On The Operation Of Regional Power Grid And Its Preventive Measures

With the development of society and national new energy policy, distributed power supply has been developed rapidly in China. The main form of the current distributed power supply with small hydropower, wind power, photovoltaic power generation, biomass energy etc. A certain area is located in the south of the Yangtze River, the annual average rainfall of 2100 mm, very rich in hydropower resources. Dotted with small hydropower station using a variety of forms connected to the grid, the low-voltage power grid system from a single power supply radiation type network for double or multi terminal active network, and small hydropower most of installed capacity is small, the adjustable ability difference of runoff hydropower station, the output of great uncertainty. The grid operation of distributed small hydropower will affect the structure of the distribution network, the size of the short circuit current, the flow and distribution of the distribution network, and the voltage level.In order to effectively eliminate the negative effect that the large scale grid connected to the power grid operation, the influence of distributed power supply on the operation of the power grid is studied, and it is necessary and urgent to take effective preventive measures. In this paper, a system analysis is made on the typical effects of small hydropower as the representative of the distributed power supply on the protection device, safety device, power network voltage and so on, based on relevant technical standards and operational experience, technical innovation, using a special kind of coincidence gate, adjust the neutral point gap distance, and optimize the operation mode of power network and relay protection setting value, effectively reduce the adverse effect of distributed small hydropower on the operation of the power grid. Through practice test, it has achieved remarkable results, which ensured the distributed generation of grid connected power generation, and maintained the safe and stable operation of the power grid.