Analysis of Sensitivity of Identification of Consumers Which Affect the Quality of Electricity, by Method of Conditional Powers

Abstract

Based on the analysis of methods for detecting sources of harmonic distortions using integral values of capacities, it is established that they do not allow to distinguish harmonic components that determine the currents of the reciprocal and zero sequences, as well as to detect the asymmetry of loads in reverse and zero sequences. The sensitivity to the detection of nonlinear consumers, which distorts the quality of electric power, by the method of conditional capacities is analyzed, which is based on the use of the mean square values of the conditional capacities of the reciprocal and zero sequences. In order to evaluate the sensitivity, it is proposed to use the ratio of the mean square values of the conditional active and reactive capacities of the reverse and zero sequences to the value of the total power of the harmonic component, which is the basis for forming the currents of the corresponding sequences. It is shown that sensitivity is high enough for all indicators. Load imbalance does not reduce the sensitivity of the method. The use of average values of the conditional capacities of the reverse and zero sequences allows us to identify consumers who have asymmetric loadings in reverse and zero sequence. Increasing the contents of higher harmonics of third-party users (systems) does not affect the sensitivity of consumers with different distortions of the controlled consumer towards the rest of consumers. Some decrease in sensitivity occurs for consumers with the same nature of distortions of the consumer and the system, which leads to overlaying the harmonic currents of the system on the currents of the consumer by amplifying or weakening them. In this case, the sensitivity remains high . The method provides reliable identification of consumers whose current distortion is at least 10 % of the distortion current of the remaining consumers (systems).