高压电网电流互感器饱和对继电保护的影响应用分析与研究

在电力系统中,由于电流互感器选择不当,故障时电流互感器可能在瞬时内承载近百倍的故障短路电流,造成电流互感器严重饱和。通过详细分析对机电式、电磁式饱和特性以及饱和程度、模拟式以及微机继电保护装置的动作特性的影响以及理论计算,探求合理的电流互感器选择方法。为解决此问题,一个可能办法是选择保护安装处最大短路电流与其电流互感器的饱和倍数来选择,同时增强电流互感器的抗饱和能力,合理选择继电保护装置和电流互感器,以保证在最大短路电流下不致饱和。提出了提高继电保护装置在电流互感器饱和时测量动作正确性的对策。

Analysis and Study on Effects of Saturation of Current Transformers on Relay Protection in the High Voltage Grid

Reactive power optimization of the power system is a nonlinear combinatorial optimization issue with multiple constraints. Evolutionary strategy algorithm shows the unique advantages in solving the problem of this sort. The penalty function method is the most commonly used method for evolutionary algorithm to solve the constraint problem, but the penalty coefficient is difficult to be determined reasonably. In this paper, stochastic ranking of evolutionary algorithm is applied in the reactive power optimization, which effectively avoids the difficulties in determining the penalty coefficient. Improvement is also made in the coding method and the evolution termination criterion. The standard tests have proved effectiveness of the improved algorithm.