A STUDY OF SHORT CIRCUIT ANALYSIS AND LOAD FLOW OF 132KV SUBSTATION USING ETAP AT BAHAWALPUR

Abstract

A short circuit analysis is a crucial for any power grid station because it damages the technical devices that installed on the grid. This research tries that if short circuit and faults occurred, how it will be affected on the whole grid as well as load flow. Generally there are three types of faults occurred in the grid and these are triple line fault, double line to ground fault and single line to ground fault. The load flow method is the tool to analyze the grid system. There are different methods for load flow analysis as Newton Raphson method, Gauss-Siedel method and Fast-Decoupled method. The three load flow methods have been compared on the basis of number of iterations obtained. Newton Raphson method is one of the best relevant methods to this study; hence, Newton Raphson method is applied to analyze the load flow of 132kV grid station in Bahawalpur. The Load flow analysis of grid is carried out through simulation tool ETAP. In proposed system, there are 128 distribution transformers that have a rating from 100KVA to 500KVA. During the load flow analysis, it is observed up to 18% losses in this grid. These losses are the sum of active losses and reactive losses. The active losses are 5.382 KVA and reactive losses are 4.980 KVA. It was seen that many of the distribution transformers and distribution lines are overloaded. There were eight positions where faults occurred, which are located at bus 96, bus 1100, bus 890, bus 1195, bus 1235, bus 1280, and bus 1338. A three types of fault observed that are LLL LG and LLG. Short circuit major reasons are moisture, trees and sudden variation in loads. All the results are calculated by using proposed methodology. Short circuit analysis gives complete information about line to ground fault, double line to ground fault and triple line to ground fault. After installing the accurate rated on protective devices, such as circuit breaker and protective relays. Then the line to ground fault, double line to ground fault and triple line fault are reduced from 18 % to 11%. This will help to overcome losses of transformers.