A New Method for Online Determination of the Location of Switched Capacitor Banks in Distribution Systems

Abstract

This paper describes two new approaches for the determination of the direction of switched capacitor banks as well as an efficient technique for estimating the distance of switched capacitors from the monitoring location in distribution systems. At first, two new indices based on branch voltage and current changes immediately after the capacitor switching instant are proposed for determining the direction of switched capacitor banks. The wavelet transform is used to detect the exact instant of switching. Then, a new technique based on linear circuit theory is proposed to estimate the distance of the switched capacitor bank from the monitoring location using capacitor switching transient data. Simulation results show that the error of the estimated distance is acceptable. A combination of the approaches for direction finding and the technique for distance estimation provide a novel method for determining the location of switched capacitor banks in real distribution systems. The method is valid in all normal, back-to-back, and abnormal switching of wye-and delta-configured capacitor banks. Also, the size of the capacitor bank has no effect on method accuracy. The efficacy of the proposed method is validated by using the IEEE 13-bus and 34-bus distribution systems.

A Simple Method for Determination of Switched Capacitor Bankin Power Distribution Systems

“…The proposed method in [6] is introduced only for the category of capacitor banks that are placed at the downstream of the monitoring location and the distance estimation algorithm totally depends on switching instant so that the capacitor bank switching at each instant except for the time of crossing the voltage signal at peak, will result in many errors in distance estimation. In the represented algorithm in [10] which depending totally on the switching time, the effect of reactance laterals branches on estimating distance between the capacitor bank and the monitoring location ignored. In other words, in this method, generally, load inductance is considered very larger than thevenin and line inductances (more than 10 times), but if the number of system loads in the branch is large, since these loads are parallel, the inductance of equivalent load decreases intensely and the current from the same branch will be increased which can cause the error of distance estimation rises up to 40 %.…”

“…11. The sample distribution system with two switching capacitors in the branch (2) Two approximately similar methods to estimate distance between the capacitor bank and the monitoring location are proposed in [6] and [10] using circuits theories and the initial changes of the voltage due to capacitor bank switching. The proposed method in [6] is introduced only for the category of capacitor banks that are placed at the downstream of the monitoring location and the distance estimation algorithm totally depends on switching instant so …”

“…Due to the phase difference, the voltage of each phase at the switching instant is in a different situation and because parameter (K) depends on voltage value immediately Regarding (10), it can be written: …”

“…In which method, the transient duration and the current energy of transient state resulted from two levels of the discrete wavelet transform are used to train the neural network. A method is proposed in [10] to assessment of the direction and estimating the distance between the capacitor bank and monitoring location by the transient current and voltage of each phase. The efficiency and the precision of this method is totally depend on the switching instant so that the switching at each time except for the instant of the crossing the voltage at peak, will lead to error in determining the direction and distance estimation.…”

An Algorithm on Optimal Placement Decision of Automatic Switches for 6 Sections/3 Links Configuration in DAS

“…In [2][3][4][5][6], the placements of switches were located using the intelligence algorithms. The switch location,which takes the operating reliability into account, was introduced in [7][8][9]. Moreover, methods considering various economic viewswere explored in [10].…”