变电站地电位干扰及抗干扰措施研究

Research on Earth Potential Interference and Anti-interference Measures of Substation

探讨了发电厂、变电所因地电位分布不均对计算机综合自动化系统造成的影响,即在雷电流入地时冲击电位分布造成的干扰,在工频大电流入地时由局部电位升高造成的干扰,以及变电站内发生接地短路时造成的电弧干拢。分析了地电位干扰产生的原因,针对干扰的途径及方式提出了防止地电位干扰的具体措施:降低接地网的接地电阻,限制地电位升高;设计接地网时应尽量采用方孔地网以改善地面电位分布,限制局部电位升高;改进计算机测控系统的接地;计算机测控系统应屏蔽接地;以保证变电站的安全稳定运行。

The impact of uneven ground potential distribution at power plants, substation on the computerized integrated automation system is approached to, interference caused by impulse potential distribution when the lightning flows into the earth, interference caused by local potential increase when power frequency high current flows into the earth, arc interference caused by the short circuiting occurred in the substation. The cause of potential interference has been analysis. Aimed to the path and mode of the interference, specific precautions against potential interference has been proposed： to reduce the resistance of grounding grid, to restrict ground potential rise; to use the square hole grounding grid for improving the ground potential distribution at grounding grid design, to restrict the local potential increase; to improve the grounding of computerized monitoring and control systemby shielding for ensuring safe and stable operation of the substation.