A new method with minimum number of monitoring points for flicker source tracing by wavelet transform

Abstract

Summary Recently, both utilities and consumers have paid great attention to voltage fluctuation (flicker) problem, which is defined as low‐frequency fluctuation on the base signal of voltage. For mitigating the flicker, identification of its source is the first step. In this paper, a new method is proposed for identifying the location of flicker sources in a multi‐flicker sources power network in a more reliable and precise manner by a minimum number of monitoring points. This method is based on the wavelet transform (WT), the approximate model of the line and flicker power theory. In addition, in this method, a new factor is proposed for determining the contributions of individual consumers and utility providers in the global flicker level of a common coupling bus‐bar. For validating the performance of the proposed method, comprehensive simulations have been performed in MATLAB environment on a single‐ and multi‐flicker sources system based on IEEE 34 node test feeder. As proved by the results, the proposed method is able to identify the contributions and locations of flicker sources with higher reliability and accuracy compared with other methods.

A new approach for the simultaneous identification of the location and individual contribution of multiple flicker sources using the least number of monitoring points

“…Then, the exact location of the flicker source is identified using the amount of voltage flickers determined in the fifth step (calculating the contribution) and comparing them together. Considering that in tracing the location of flicker source using method 37 the relative error is less than the maximum allowable relative error ( E r‐max ), it can be concluded that using the data of only five monitoring points the proposed method in this article and Reference 37 can detect the exact location of the flicker source. The value of E r‐max depends on the identified location of the flicker source using the method, in Reference 37 and if the relative error is less than E r‐max , the location of the flicker source has been successfully traced.…”

“…If the flicker source location, traced by the method in Reference 37 is between the busbar n and the point y , the flicker source location is considered to be on busbar n ; otherwise, it is considered to be on busbar n + 1. Therefore, the maximum allowable relative error is equal to half the distance between busbars n and n + 1 divided by the flicker source distance ( d ).…”

“…Moreover, m u ( t ) and m i ( t ) are the flicker components. Therefore, FP is computed as follows: where T is the integration time, which is selected as 2 seconds 36,37 . The sign of FP indicates the direction of flicker sources (up or down) with respect to a monitoring point.…”

“…A new method was proposed in Reference 37 to identify the location and contribution of flicker sources using fewer monitoring points. The proposed method initially selects three monitoring points along the main line of the network.…”

“…We try to improve the method in Reference 37 to obtain the exact location as well as the contribution of each flicker source and injected voltage and current flicker signals. In the proposed method, the voltage and current signals are measured at the input of three busbars along a certain line.…”