摘要
为避免一刀切的“间隙安装策略”带来的成本高问题,有必要针对分布式电源从配电网接入情形给出间隙安装策略的建议。通过建立配电网发生单相接地故障时的复合序网络,分析不接地变压器中性点工频过电压的产生机理;在PSCAD/EMTDC中搭建计及低压侧分布式电源接入的110 kV电网模型,对比分析不同类型和容量分布式电源接入下变压器中性点的电压值或电压波形的变化规律。结果表明:接入PQ控制型逆变型分布式电源且其容量显著大于低压侧负荷容量时对变压器中性点绝缘安全的威胁程度最高;根据不同变压器中性点绝缘水平、接入分布式电源的类型和容量应选择不同的间隙安装方案。
To avoid the high cost problem of the one-size fits all gap installation strategy,it is necessary to give suggestions on the gap installation strategy for the access of distributed power from the distribution network.The generation mechanism of power frequency overvoltage at neutral point of ungrounded transformer is analyzed by establishing composite sequence network when single-phase grounding fault occurs in distribution network;a 110 kV power grid model considering the low-voltage side distributed power is built in PSCAD/EMTDC,and the variation of voltage value or voltage waveform of transformer neutral point under different types and capacities of distributed power access is compared and analyzed.The results show that when the capacity of the PQ-controlled inverter-based distributed power supply is significantly greater than the load capacity of the low-voltage side,the threat to the insulation safety of the transformer neutral point is the highest;different gap installation schemes should be selected according to the insulation level of different transformer neutral points,the type and capacity of distributed power supply.
作者
秦睿
郭鸿毅
陈煜
Qin Rui;Guo Hongyi;Chen Yu(Zhongshan Power Supply Bureau of Guangdong Power Grid Co.,Ltd.,Zhongshan,Guangdong 528401,China)
出处
《机电工程技术》
2023年第8期256-260,共5页
Mechanical & Electrical Engineering Technology
关键词
分布式能源
单相接地故障
不接地变压器
中性点
工频过电压
特征
间隙安装策略
distributed generation
single phase grounding fault
ungrounded transformer
neutral point
power frequency overvoltage
characteristics
gap installation strategy
