International Journal of Research and Scientific Innovation (IJRSI) |Volume IX, Issue X, October 2022|ISSN 2321-2705
Optimal Placements and Sizes of Capacitor Banks for Voltage Support and Minizing Total Cost
Nguyen Thi Thanh Thuy
Electrical Faculty, Thai Nguyen University of Technology, Thai Nguyen, Viet Nam
Abstract: This paper presents a method to determine optimal placements and sizes for capacitor banks using constrains about bus voltage and cost function based on the OCP tool. The constrains are considered in three cases, including the limitation of rated compensation value, no compensated limitation of rated value and assigned some buses to compensate. This new approach can help dispatchers evaluate all information about the grid and give suggestions about the compensated process when compared to other cases. Above proposes were applied into a 35 kV grid and simulated on the ETAP software. Simulation results showed optimal placements and rated sizes for capacitor banks very detailed. After implementing capacitors, voltage values at all buses were in allowable range and cost function was minimum. Simulation results provided were also provided some additional information such as power losses in whole grid, installation and operation cost, loss reduction saving, yearly profit, accumulative profit in whole planning period to have total evaluation about the compensation problem.
Index Terms: Capacitor bank, Compensation, ETAP software, Optimal placement, Optimal size, Optimal cost, Voltage quality.
I. INTRODUCTION
Many researchers are interested in compensating reactive power in power systems. When implementing a capacitor into a grid, power flows in whole grid and bus voltage can be changed and it can be make some benefits. Placement and size of any capacitor banks will affect to economic and technical factors. So, it must be calculated and evaluated carefully.
Benefits of implementing capacitor banks can be: reduce active power consumption from power system; reduce power load for medium voltage transformers and lines; reduce power losses; improve voltage quality [1-7]. However, capacitor banks can create additional cost for purchasing capacitors, operating compensation station and power loss in self capacitors [1-7]. Compensation problems are often solved to determine the number of compensation stations, the optimal placements in the grid and the operating modes of capacitors to achieve the highest benefit or the minimum value for cost function.
Before establishing a compensation problem to determine placement, rated power and the number of capacitors for each station, it must be designed the way to implement and control capacitor banks. Objective function is often total algebra of benefit and cost factors that are calculated in a common money unit. Uncalculated factors and technical standards are considered as constrains and limitation. Although there are