高压电力电缆——架空混联线路接地保护方案探讨

The new scheme discussion of grounded protection for high voltage cables—aerial line

从正、负、零序阻抗特性以及零序阻抗与零序电流的关系入手,分析了架空线路与电力电缆电气特性的主要区别及传统接地保护应用于电力电缆线路所带来的弊端。根据电力电缆分布参数模型,在充分考虑电力电缆故障情况下,零序电流与零序电抗之间呈非线性关系的特性,提出了新的自适应接地距离保护和零序电流保护方案,通过迭代和拟合的方法来计算短路点的零序阻抗和零序电流,并最后判定故障位置。新的自适应接地距离保护和零序电流保护方案减少了电力电缆特性对接地距离保护的影响,其抗过渡电阻能力得到了改善,能满足运行规程对零序电流保护的要求。通过ATP建模仿真和MATLAB程序计算,新算法有效性得到了验证。

Starting with the traits of zero order impedance and the relationship between zero order current and zero order impedance, analyzes the main differences of electric traits of power cables and aerial lines and the disadvantages of applying power cables into the traditional grounded protection. According to distributing parameter model of power cables, considering fully failure of power cables and the traits of non-linear relationship between zero order current and zero impedance, puts forward the scheme of new self-adjusting grounded distance protection and zero order current. By the iterative and simulating methods, calculates the zero order current and zero impedance of short circuit point and confirms finally the position of failure. The scheme reduces the influences of the power cables traits for the grounded distance protection, improves the ability of resisting the transition resistance, satisfy the requests of running rules for the zero order current protection. Via ATP modeling, emulation and MATLAB program computing, validates the validity of new algorithm.