高压直流接地极对管道电磁阀的干扰影响研究

Study on interference effect of HVDC grounding electrode on electromagnetic valve in pipeline

针对高压直流输电(HVDC)接地极处于单极大地回路运行工况下,很大的入地杂散电流可能产生电磁阀发生误动作的风险,影响管道正常运行。建立了传导干扰对电磁阀线圈影响的数学模型,研究了直流杂散电流引起电磁阀误动作的机制。采用数值模拟的方法,建立国内某1 100 kV特高压直流输电工程接地极对附近管道干扰的仿真模型,并设计了管地电位实时数据采集系统。仿真及现场测试结果表明,干扰电压以接地极距离管道最近位置为中心,依次向上下游递减;冬季电磁阀受到的直流干扰是夏季的3.43倍;仿真结果和实测结果基本吻合,误差在10%以内;沿管线增设4个和6个绝缘接头后使得管地电位差降低62.1%、71.4%。为可靠预防电磁阀异常工作,在冬季应该加强阀室巡检,并沿管道上下游适当位置安装绝缘接头。

As the grounding electrode of HVDC is in single electrode blocking condition, the large stray current into the ground may cause the electromagnetic valve misoperation risk, affecting the normal operation of the pipeline. The mathematical model of the influence of conducting interference on the solenoid valve coil is established, the mechanism of misoperation of electromagnetic valve caused by dc stray current is studied. By means of numerical simulation, a simulation model of grounding electrode interference to nearby pipelines in a 1 100 kV UHVDC transmission project in China was established, and a real-time data acquisition system of ground potential was designed. Simulation and field test results show that the dc interference of the electromagnetic valve in winter is 3.43 times that in summer. The simulation results are basically consistent with the measured results, and the error is within 10%. After adding 4 and 6 insulated joints along the pipeline, the ground potential difference of the pipeline is reduced by 62.1% and 71.4%. In order to reliably prevent abnormal operation of electromagnetic valve, inspection of valve chamber should be strengthened in winter, and insulation joint should be installed along the pipeline upstream and downstream.