过电压线路长度的探讨

在对中性点不接地的变压器供电的三相电路中,当一相或两相导线断线时,由于线路电容与非线性电感之间的铁磁谐振,而产生稳态过电压。结果使避雷器及所连接的仪器、设备发生故障,造成危害。本文根据产生过电压的参数,取决于线路长度的原理,应用线性电路理论,推导出三相系统断线时,不产生过电压的计算公式,以便根据变压器容量,确定安全线路长度。

Studies on Line Length Immune to Overvoltage

When one or two conductors in a three-phase circuit supplying power to ungrounded transformer break and produce a steady-state overvoltare,due to ferroresonance between line capacitance and nonlinear inductance, failure of lightning arrester and connected equipment occurs,leading to equipment damage.Mathematical equations were developed to predetermine the safe line length as a function of transformer size,for prevention of overvoltage,based on the principle that overvoltage paramerters depend on line length and on linear circuit theory.