基于图形相似度的分布式能源接入配电网差动保护方案

Differential Protection Scheme of Distributed Energy Access to Distribution Network Based on Graph Similarity

针对传统配电网其拓扑结构和故障特性由于分布式新能源的接入,发生了一定改变,对配电网的继电保护带来了新的挑战,提出一种依据线路两端电流波形相似度的自适应差动保护方案。该方案通过分析线路两端的电流波形特征,利用Hausdorff距离算法计算电流的相似度,在此基础上构建电流差动保护的制动系数,对故障区域进行自适应判别。在PSCAD/EMTDC软件中搭建基于分布式电源的配电网模型,对所提保护方案进行仿真验证,仿真结果表明该方案能准确判别故障区域,抗过渡电阻能力强,且不需要电压信息和增加额外保护装置,具有同时兼容低成本与高可靠性,抗同步误差能力强等优点。

In view of the fact that the topology and fault characteristics of the traditional distribution network have changed due to the access of distributed new energy,which brings new challenges to the relay protection of the distribution network,an adaptive differential protection scheme based on the current waveform similarity at both ends of the line was proposed.By analyzing the current waveform characteristics at both ends of the line,the Hausdorff distance algorithm was used to calculate the current similarity.On this basis,the braking coefficient of current differential protection was constructed and the fault area was self-adaptive discriminated.A distribution network model based on distributed power was built in PSCAD/EMTDC software,and the proposed protection scheme was simulated and verified.The simulation results show that the scheme can accurately identify the fault area,has strong resistance to transition resistance,and does not require voltage information and increase.The additional protection device has the advantages of being compatible with low cost and high reliability,and strong anti-synchronization error ability.