A Novel Method for Contingency Ranking Based On Voltage Stability Criteria in Radial Distribution Systems

Abstract

Voltage stability margin regarding with contingency ranking in radial distribution system using novel method is proposed in this paper. Two new indices are derived to forecast the voltage stability in the radial distribution feeders. Here, RSI_N(r) is the radial stability index calculated for each bus and utilized for forecasting the voltage stability. The second index is derived by finding the effect of receiving end voltage change on voltage stability index at a specific bus. Contingency planning by delta analysis method improves the reliability of the system. The proposed system is employed for optimally ranking the contingencies. Impact on voltage stability due to contingencies like loss of FACTS devices, loss of distributed generation (DG) sets and loss of lines is carried out on radial distribution feeders and compared the experimental results with the proposed method using MATLAB platform. The proposed indices are implemented on the test systems and outcomes are compared to existing indices on literature and it is viewed that the proposed indices are effective on predicting the system stability. Contingency due to a loss of DG set, due to a loss of reactive source, due to a loss of line, due to loss of DG set are the considered test cases. Voltage profile improvement using Static VAR Compensator (SVC)-DSTATCOM is also employed in this paper. The proposed system is also tested under 15, 28 bus system, IEEE-69 and 123 bus system.