新型基于频率特性的电缆故障定位方法

New Cable Fault Location Method Based on Frequency Characteristics

海底长电缆频率特性是电缆状态检测的基础。以220kV海底电缆为例,将变频电压源施加到电缆终端,在分布参数模型的基础上,研究末端开路和短路状态下沿线电压的频率特性。然后通过分析初始峰值电压和入口阻抗频率特性,给出一种新的电缆故障的定位方法,该方法首先测量电缆低频下的入口阻抗相位角来确定故障类型,然后根据产生入口阻抗初始峰值时频率和产生电压初始峰值时频率的关系,利用所推计算式进行故障定位。最后运用PSCAD软件的精确模型仿真对定位公式进行了验证。研究表明:根据电缆频率特性推导的故障定位计算式准确、方便,对于开发海底电缆的故障定位的新技术有参考作用。

The frequency characteristic of the submarine cable is the basis for cable state detection.Taking a220kV submarine cable as an example and applying variable voltage source to the cable terminal,this paper studies frequency characteristics of voltage along the cable under states of terminal open-circuit and short-circuit based on the distribution parameter model.By analyzing frequency characteristics of the initial peak voltage and entrance impedance,it presents a kind of new cable fault location method which firstly measures phase angle of entrance impedance at low frequency of the cable to determine fault type,and then uses the formula to perform fault location according to relationship between the frequency of the initial peak of entrance impedance and the frequency of the initial peak of generated voltage.Finally,it uses the accurate model of PSCAD software to verify the location formula.The research indicates the fault location formula derived from frequency characteristics of the cable is accurate and convenient,which is useful to develop new technologies for fault location of submarine cables.