变电站就地化电子装置供电电源的电磁骚扰耦合和抑制

Electromagnetic Disturbance Coupling and Suppression of On-site Electronic Device Power Port in Substations

变电站的断路器和隔离开关操作能够产生暂态地电位升(transient earth voltage rise,TEVR)和强烈的空间电磁辐射,对变电站就地化电子装置造成严重电磁骚扰。就地化电子装置的供电电源是电磁骚扰的主要耦合路径,因此研究了供电电源电磁骚扰的耦合机理和抑制措施。研究结果表明,现有的就地化电子装置的供电电路大部分包含有连接在屏蔽箱内外之间的电源线,能够显著降低屏蔽箱的效能,将外部的电磁骚扰引入到屏蔽箱内部。提出了一种隔离变压器结构,其原边和副边绕组分别位于屏蔽箱内外,避免了跨屏蔽箱连接的电源线,试验证明其可以有效抑制供电电源引入的电磁骚扰。

The operation of circuit breakers and disconnectors in substations can produce transient earth voltage rise(TEVR)and severe space electromagnetic radiation,causing serious electromagnetic disturbance to the on-site electronic devices in substations.The power supply of on-site electronic devices is a major coupling path of electromagnetic disturbance.Therefore,this paper studies the coupling characteristics and suppression of electromagnetic disturbance caused by on-site power supply.The research results show that most of the existing power supply circuits of on-site electronic devices contain power lines connected between the inside and outside of the shielding,which can significantly reduce the efficiency of the shielding and further introduce external electromagnetic disturbance into the shielding.In this paper,an isolation transformer structure is proposed.Its primary and secondary windings are located inside and outside the shielding box respectively,averting the power lines connected across the shielding.Further experiments on this isolation transformer show that the electromagnetic disturbance introduced by the power supply can be effectively suppressed.