A novel algorithm of instantaneous symmetrical components based on trigonometric function transformation

With the method of instantaneous symmetrical components, positive, negative and zero sequence components can be gained. The traditional instantaneous symmetrical components are usually implemented under dq0 synchronization reference frame on condition that low-pass filter is adopted in, which causes aggravated dynamic performance. To solve this problem, this paper presents a novel algorithm of instantaneous symmetrical components, and gives its corresponding equations and results. The principal of proposed algorithm is based on ab0 static axis. By trigonometric function transform method, the positive, negative and zero sequence components are deduced as a sum of sine and cosine, both of them with a multiplier factor. According to this analysis, three-phase sequence components can be solved out by using of variable step-size LMS adaptive filter. The dynamic and accuracy performance is testified by the results of simulation in unsymmetrical faults and short circuit faults, which prove this algorithm is suitable for unsymmetrical faults in power system.