分布式能源脱网和其本身特性改变对线路限时电流速断保护的影响及对策

Influences of Distributed Energy Resources Off-grid and Their Attribute Change on Line Time Limited Current Protection and Corresponding Countermeasures

为解决分布式能源脱网及其本身特性改变对线路电流保护性能带来的影响,提出实时修正的保护门槛值优化方案。首先,分析分布式能源在脱网及其本身特性改变工况下线路电流的分布特征,利用PSCAD/EMTDC电磁暂态仿真软件搭建仿真模型来研究对下级线路限时电流速断保护灵敏度的影响;然后,根据上述工况下电流与功率的分布特征,通过分布式能源支路的实时测量电流对限时电流速断保护的门槛值进行修正,构造一种实时修正的保护门槛值优化方案,以适应分布式能源的不同运行工况;最后,通过仿真实验验证了所提优化方案的有效性。

To overcome the influences of distributed energy resources(DERs)off-grid and their attribute change on the performance of line current protection,a real-time modified protection threshold optimization scheme is proposed.The distribution characteristics of line current under the conditions of DERs off-grid and their attribute change are analyzed,and a simulation model is built using the PSCAD/EMTDC electromagnetic transient simulation software to study the in-fluences on the sensitivity of time limited current protection of downstream lines.According to the distribution character-istics of current and power under the above conditions,the real-time measured values of current of DER branches are used to modify the threshold value of time limited current protection,so that a real-time modified protection threshold optimization scheme is formed to adapt to different operating conditions of DERs.Finally,the effectiveness of the pro-posed optimization scheme is verified by simulation results.