自适应电流速断保护中实时计算系统参数算法研究

Algorithm study of real-time calculating system parameters for adaptive current fast-tripping protection

研究了自适应电流速断保护中实时计算系统等值参数的一种傅氏算法。首先,分析了一般全周傅氏算法在计算系统等值内阻抗时的实现方法,计算示例显示该方法由于受短路电流非周期分量的影响,会产生很大的误差。然后,研究了带补偿的傅氏算法计算系统等值内阻抗的实现方法,应用相同的计算示例对各种不同相电势初相角下的系统等值内阻抗进行了计算。结果表明带补偿的傅氏算法具有很高的精度。最后,提出了利用记忆在计算机存储器内的故障前测量电压、电流采样值计算系统等值相电势的方法,并用计算示例证实了算法具有很高的精度。

The algorithms of real-time calculating system parameters are studied for adaptive current fast-tripping protection of power system. The realizing method for calculating the system internal equivalent impedance by general full-wave Fourier algorithm is analyzed. With a calculating example,it is indicated that the method will cause higher error because of decaying DC component. Then,a kind of Fourier algorithm removing DC component is studied. With the previous calculating example,the system internal equivalent impedances with different primary phase-angles are calculated. The results show that the latter has higher accuracy. The system internal equivalent electric potential is calculated by means of the voltage and current values measured and stored before fault. The calculating example shows its high accuracy.