锦—苏特高压直流对江苏电网变压器直流偏磁的影响

±800 kV锦-苏特高压直流工程大功率双极不平衡调试期间,江苏电网建设了直流偏磁在线监测系统,开展了直流偏磁带电检测工作。对距苏州换流站接地极100 km内主要500 kV和220 kV主变开展直流偏磁测试,包括中性点直流电流、振动、噪声等,并研究其对江苏电网的影响。研究发现,该工程直流偏磁会造成附近主变振动加剧、噪声增加,但未见造成局部过热现象,对主变的安全运行影响较小。提出了对新投运主变出厂试验增加直流偏磁试验和加强直流偏磁在线监测跟踪的建议。

Impacts of Jin-Su HVDC Project on Transformer DC Magnetic Bias in Jiangsu Power Grid

Wind power and solar power with the stochastic characteristics have greater influences on fault recovery strategies of distribution system. This paper proposes fault recovery strategies for the distribution system considering the influences of wind and solar power. Firstly, a simplified steady-state equivalent model of an asynchronous generation is used to demonstrate the wind power generators, and the stochastic model of wind speed is adopted. The slip ratio is added into Jacobian matrix to calculate power flow of distribution system. The probabilistic output of solar power is considered as an injection power which is influenced by solar irradiance. Secondly, three-point estimate method is employed to solve prohabilistic power flow of distribution systems. The recovery problem is presented as a multi-objective problem with the minimum mean of the system loss and the numbers of switch operation. Fast Elitist Non-Dominated Sorting Partheno-Genetic Algorithm is used to solve this multi-objective problem. A test system is used to show that the models and algorithms proposed are efficient.