基于低频阶跃脉冲的矿井低压漏电保护技术

A low-voltage current leakage protection technology for mine sites based on low-frequency step pulse

为了解决矿井低压系统采用附加直流检测式漏电保护方法不具有选择性的问题,使系统在发生漏电后及时掌握故障程度和位置,提出了基于低频阶跃脉冲注入的漏电保护新方法。研究了矿井低压供电系统的结构,通过向系统注入一低频阶跃脉冲信号,得到了基于注入信号特征量的单相漏电绝缘检测和故障选线方法。利用MATLAB进行了漏电仿真,仿真结果表明:此漏电保护方法能够较准确计算出1-200 kΩ范围内的漏电阻值,误差在4%以内,且能可靠确认故障线路,有效排除了漏电阻、分布电容、低频阶跃脉冲信号频率和谐波次数的影响,可实现不同工况下的绝缘检测和选择性漏电保护,为矿井低压系统的供电安全提供了技术保障。

In order to solve the problem that the additional DC detection leakage protection method was not selective in the low-voltage system for mine sites and to enable the system to grasp the fauet degree and location in time after current leakage occurs,this paper proposes a new leakage protection method based on low-frequency step pulse injection.The structure of the low-voltage power supply system is studied,and a single-phase leakage insulation detection and fault line selection method based on the characteristic quantity of the injected signal is obtained by injecting a low-frequency step pulse signal into the system.MATLAB is used for leakage simulation and the results show that this method can accurately calculate the leakage resistance In order to solve the problem that the additional DC detection leakage protection method was not selective in the low-voltage system for mine sites and to enable the system to grasp the fauet degree and location in time after current leakage occurs, this paper proposes a new leakage protection method based on low-frequency step pulse injection. The structure of the low-voltage power supply system is studied, and a single-phase leakage insulation detection and fault line selection method based on the characteristic quantity of the injected signal is obtained by injecting a low-frequency step pulse signal into the system. MATLAB is used for leakage simulation and the results show that this method can accurately calculate the leakage resistance values between 1-200 ki1 with an error within 4%, and can reliably confirm the fault line, effectively exclude the influence of leakage resistance, distributed capacitance, low-frequency step pulse signal frequency and harmonic number, realizing insulation detection and selective leakage protection under different working conditions, which provides technical guarantee for the safety of power supply of the low-voltage system of the mine sites.