OPTIMAL ALLOCATION OF CAPACITORS AND DGS FOR TECHNO-ECONOMIC BENEFITS IN RADIAL DISTRIBUTION SYSTEM

Abstract

Power loss minimization and voltage stability improvement are important areas of power systems due to existing transmission line contingency, financial loss of utility and power system blackouts. Optimal allocation (i.e. siting and sizing) of Distributed Generation (DG) and Optimal Capacitor Placement are the best ways to strengthen the efficiency of power system. In the present work, a Evaporation-rate based water cycle algorithm has been taken into account to allocate capacitor banks and DGs along the radial distribution network. The objective function is adopted to minify the system power loss, to improve the system voltage profile and finally to carry out for power loss reduction with economic point of view. Firstly, capacitor placement is applied to standard IEEE buses. In the next stage, Distributed Generations is incorporated in the standard IEEE buses, thirdly capacitor and DGs with unity pf are incorporated simultaneously in the IEEE bus system and finally capacitor and DGs with controllable pf are incorporated simultaneously in the IEEE bus system. Finally, practical distribution feeder (i.e., New Chabahil Feeder and Daachhi Feeder) of Kathmandu valley will be taken to apply the theoretically proven technique to reduce voltage drop and power loss. The overall accuracy and reliability of the approach has been validated and tested on radial distribution systems with differing topologies and of varying sizes and complexities. The results shown by the proposed approach have been found to outperform the results of existing heuristic algorithms found in the literature for the given problem. The test was performed for four cases. Case I: placement of capacitors only, Case II: Placement of DG only, case III: Placement of DG (unity pf) and capacitors simultaneously, Case IV: Placement of DG (with controllable pf) and capacitors simultaneously taking into consideration for technical objectives only, Case V: Placement of DG (with controllable pf) and capacitors simultaneously taking into consideration for techno-economic objectives. The power loss found with my thesis work is lower than that of with the methodologies in the reference paper. For IEEE 33 bus system, power loss in case I, case II, case III, case IV, and case V was 34.79%, 62.10, 90.23%, 92.04%, and 63.67 % of the base case respectively. Similarly, for IEEE 69 bus system, power loss in case I, case II, case III, case IV, and case V were 35.34%, 69.14%, 94.36%, 96.24%, and 35.53% of the base case respectively the power loss. Moreover, the results for the practical systems (Daachhi feeder and New Chabahil feeder) are supposed to have considerable upgradation in the Nepalese distribution system in the future for

lower power loss and better voltage profile. For Daachhi Feeder, power loss in case I, case II, case III, case IV, and case V was 50.25%, 48.52%, 96.10%, 96.77%, and 70.95% of the base case respectively. Similarly, for New-Chabahil Feeder, power loss in case I, case II, case III, case IV, and case V were 37.46%, 63.54%, 97.10%, 98.23%, and 54% of the base case respectively the power loss