Formulation of impact of voltage — Change in the radial power-flow with tap — Change transformer

The demand for electrical energy is ever increasing in the World. For that an AC (Alternating Current) Power Distribution is most commonly used system in operation. Approximately 20% of the total electrical energy generated is lost during transmission (4-6%) and distribution (15-18%). In this context, it is necessary to minimize the distribution losses, which intern improves the amount of power significantly. An industrial customer supposed to reduce the losses in the low tension-side under tolerable voltage limit. In case the customer is failed to maintain the system voltage well within the limit, then unnecessary penalty is charged by the power supply board. As per the demand and service, it is necessary to place tap-change transformer or regulating transformer to maintain the acceptable voltage limit. For that, first various literature reviews were collected on role of tap-changing transformer in power distribution study. Further, the paper developed formulas on the impact of tap-changing transformer in the distribution power-flow study. The updated formulas used to determine bus-power, bus-current and bus-voltage. Furthermore, the role of tap-changing towards saving of real power cost is estimated. To obtain the load flow solution, the input-data details of the network containing tap-change transformer were fed into modified power flow equations. The proposed algorithm is successfully demonstrated on an IEEE 15-bus network and voltage regulation are presented. The test results obtained are validated through MATLAB Version: 9.2.0.538062 (R2017a). The proposed method presented in the paper is found to be flexible and efficient.