中短波发射台对变电站二次系统影响分析

Analysis on Impact of Medium and Short Wave Radio Transmitting Station on Secondary System of Substation

为确定中短波无线电发射台工作时是否对变电站二次系统微机继电保护产生电磁干扰影响,对无线电发射台中的直立天线、水平双极天线、菱形天线和对数周期天线的电场强度以及变电站二次系统微机继电保护控制电缆芯线回路两端由此感应的纵向电压和横向电压进行了理论计算,计算结果表明纵向电压和横向电压都不超过DL/Z713—2000规定,说明变电站二次系统不会受到中短波无线电发射台的电磁干扰影响。但建议微机继电保护的控制电缆须采用有钢带铠装的铜屏蔽层电缆,微机保护控制电缆回路加装低通滤波器。

For ensuring whether it will produce electromagnetic interference on microcomputer relay protection of substation secondary system when the medium and short wave radio transmitting station is working, this paper studies theoretical calculation on electric field intensity of vertical antenna, horizontal dipole antenna, rhombic antenna and log-periodic antenna and longitudinal voltage and lateral voltage induced at both ends of microcomputer relay protection control cablecore of sub- station secondary system. The calculation result shows longitudinal voltage and lateral voltage are not exceeding provisions of DL/Z 713-2000 which explains that the secondary system will not affected by electromagnetic interference of medium and short wave radio transmitting station. But it suggests control cable should be replaced by a kind of copper shield cable with steel tape armoring and lowpass filter should be installed for control cable circuit.