零地电位接地网的设计方法及其应用——修改接地电阻安全标准可行性论证

Design Method of Ground Grid with Zero Earth Potential and Its Application:Discussion on Feasibility of Revising Safety Standard about Earth Resistance

提出了零地电位接地网概念——发电机与其直配供电的用电设备所共用的接地网,当发电机或任何一台用电设备发生接地故障时,该接地网的接地电阻等于零。在零地位接地网的范围内建设同级电压的发电-用电系统,可保证在该接地网内工作人员的人身安全,即无触电伤亡事故,对接地电阻值可不作具体规定或要求,敷设接地网时也不需要“满山挖地沟”(最适合海上孤岛驻军的独立自备发、用电系统的联合接地网)。基于零地电位接地网的新概念,不接地、消弧线圈接地和高电阻接地的高压变电站与低压电气设备共用接地网时,接地网的接地电阻可由规程所要求的R≤4Ω放宽到R≤10Ω,这样,可大量节约钢材,减少大量地沟开挖工程量,从而达到大幅度降低接地工程费用的目的。

This paper presents the concept of ground grid with zero earth potential, i.e. , the earth resistance of ground grid shared by a generator and the directly served power consumption equipments equals zero when an earth fault happens to the generator or any one of the power consumption equipments. Constructing power generation-consumption system of the same voltage level within the zero-earth-potential ground grid protects the personnel working in the grid from electric shock casualties, dispenses with specific requirement on the earth resistance value, and dose not entail large-scale tunneling, which is most suitable for independent and self-provided generation-consumption combined ground grid for the garrison on an isolated island. According to the new concept of zero-earth-potential ground grid, as for ground grid shared by HV substations and LV electric apparatus in isolated, arc-suppression-coil-earthed and high-resistance-earthed neutral systems, the earth resistance of the ground grid can be loosened from stipulated R≤4 Ωto R≤10 Ω, which considerably retrenches steel consumption and tunneling amount, so as to greatly curtail grounding engineering expenses.