振荡时电力系统瞬时频率的实时测量

提出了一种实时测量电力系统瞬时频率的算法。该算法经严格的数学推导，并结合简单的迭代和泰勒展开法而得到。由算法测得的瞬时频率可以用来消除负序不平衡电流、准确地提取故障分量和测量距离阻抗值，使继电保护装置能获得准确的参数信息，以便进一步提高当前保护装置的动作性能。文中分析了影响该算法精度的主要因素，解决了算法中的过零点问题。算法本身考虑到对噪声的抑制能力以及对A／D变换引起的量化误差的适应性。实验伤真结果表明该算法具有较高的测量精度，实时性强，基本不受两侧电势幅值不同的影响。

REAL-TIME MEASUREMENT OF POWER SYSTEM INSTANTANEOUS FREQUENCY WHILE POWER SYSTEM SWINGS

An algorithm for measuring instantaneous frequency of power system is presented in this paper,which applying to two current frequency components in a trans-mission line while power system swings. The method is based on rigorous mathematical deducing and recombine itself with iteration and Taylor series expansions. The measuring frequency is used for eliminating unbalanced current of negative sequence,extracting fault components and measuring impedance. The algorithm provides relaying device with accurate information so that the performance of relaying device can be improved. Main parameters that affect the accuracy of the algorithm have been discussed,and the problem of zero-point is solved too. The algorithm allows for the noise immunity characteristic and the truncation errors of A/D converter. The accuracy of this algorithm has been proved by simulation experiment. The method responds quickly to the instantaneous frequency changing, and the result will not be influenced by the voltage difference of two ends.