摘要
矿井电网谐波和弧光现象日益严重,漏电故障信号畸变,弧光漏电发生概率增大,导致故障信号畸变严重,基波分量较少,而现有矿井电网漏电保护方法采用零序基波分量作为故障特征参数,对弧光漏电辨识率较低。针对上述问题,提出了一种基于等效电导的矿井电网智能漏电保护方法。在分析漏电故障特性的基础上,根据非正弦电功率理论,以畸变零序电压为基准正交分解零序电流。采用畸变等效电导作为故障特征参数,通过比较各馈线等效电导的符号和大小辨识漏电线路:等效电导最大且符号为负的线路判为漏电支路,报警并发跳闸命令;符号为正的等效电导代表相应各非漏电馈线当前的绝缘水平,实现对电缆绝缘状态的自动监测。采用正交无功电流反映本级电网的电容电流水平,为矿井供电安全分析与故障预警提供数据支撑。仿真结果表明,该方法能同时实现漏电故障识别、漏电支路定位和电缆绝缘状态的自动监测,满足选择性、快速性和灵敏性要求,尤其适用于弧光漏电故障的辨识,有效提高了矿井供电的安全性。
The phenomenon of harmonic wave and arc light in mine power grid is increasingly serious,and leakage fault signal distortion and probability of arc light leakage increases,resulting in serious fault signal distortion and less fundamental wave component.However,the existing leakage protection methods of mine power grid adopt zero-sequence fundamental wave component as fault characteristic parameter,which has a low identification rate for arc light leakage.In view of the above problems,an intelligent leakage protection method of mine power grid based on equivalent conductance was proposed.On the basis of analyzing characteristics of leakage fault,the zero-sequence current is decomposed orthogonally with distorted zero-sequence voltage as reference according to non-sinusoidal power theory.The distortion equivalent conductance is adopted as fault characteristic parameter,and the leakage circuit is identified by comparing symbols and value of equivalent conductance of each feeder:the circuit with the maximum equivalent conductance and negative sign is judged to be leakage branch,and alarm and tripping command are issued;the equivalent conductance with a positive symbol represents current insulation level of corresponding non-leakage feeders to realize automatic monitoring of cable insulation state.The orthogonal reactive current is adopted to reflect capacitive current level of the grid,which provides data support for mine power supply safety analysis and fault warning.Simulation results show that the method can realize leakage fault identification,leakage branch location and automatic monitoring of cable insulation state,and meets requirements of selectivity,rapidity and sensitivity,especially suitable for arc leakage fault identification,which can effectively improve safety of the mine power supply.
作者
王清亮
杨博
高梅
刘新茹
李磊
郝兆明
WANG Qingliang;YANG Bo;GAO Mei;LIU Xinru;LI Lei;HAO Zhaoming(College of Electrical and Control Engineering, Xi'an University of Science and Technology, Xi'an 710054, China)
出处
《工矿自动化》
北大核心
2020年第6期59-64,共6页
Journal Of Mine Automation
基金
陕西省自然科学基础研究计划资助项目(2015JM5211)。
关键词
矿井电网
漏电保护
畸变等效电导
弧光漏电故障
非基波分量
谐波分量
电缆绝缘状态
mine power grid
leakage protection
distortion equivalent conductance
arc leakage fault
non-fundamental component
harmonic component
cable insulation state
