小电阻接地系统接地阻抗继电器动作行为分析

Analyzing grounding impedance relay action In low resistance grounding system

基于小电阻接地系统发生单相经过渡电阻接地的复合序网图,推导出A、B、C相接地阻抗继电器的测量阻抗表达式和动作特性,在阻抗复数平面上比较动作特性圆和测量阻抗,分析出故障相和非故障相接地阻抗继电器的动作情况和影响因素,得出前者受过渡电阻的影响较大、易拒动、而后者受过渡电阻和中性点电阻的影响不会误动的结论。在Matlab平台上采用Simulink工具搭建上述系统故障情况的仿真模型并进行实验,仿真结果验证了上述结论的正确性。

Based on the complex sequence network diagram of single-phase grounding through transition resistance in low resistance grounding system,the paper firstly deduces the measurement impedance expression and action characteristics of A,B and C phase grounding impedance relays,then compares the action characteristic circle and measurement impedance on the complex impedance plane,finally analyzes the action conditions and influencing factors of fault phase and non-fault phase grounding impedance relays.It is concluded that the former is easy to refuse action under the influence of transition resistance,while the latter doesn′t show false action under the influence of transition resistance and neutral grounding resistance.The simulation model of the above system single-phase grounding fault situation is built in Matlab/Simulink platform and the experiment is carried out.The simulation is used to verify the conclusion.