Online Power Transfer Regulation Between Transmission and Active Distribution Systems for High-Voltage Support

Abstract

Regulation of power transfer between High-voltage Side (HVS) and Distribution Power Systems (DPS) is an urgent issue for modern power grids. During light loading, active DPS can export the extra power to the transmission system and may create voltage rise at HVS. In other words, active DPS are highly required to provide ancillary services to HVS during its unexpected failures. Therefore, this study suggests an online centralized control approach to satisfy the international Demand Connection Codes (DCC) at Transmission/Distribution interconnection point or fulfill the power requests from HVS. A linear power-flow taking into account the voltage-dependence characteristics of electric loads is used for problem formulation. The problem is formulated as a mixed integer quadratic optimization problem (MIQP). The MIQP problem can easily be solved to its optimality solution while reducing the complex computations. The proposed method can regulate both active and reactive power transfer at the interconnection point and thus it can be operated at different modes. The proposed control method uses the Distributed Generation (DGs), Capacitor Banks (CBs), and controllable loads as control variables. The use of controllable loads can increase the responsibility level of DPS in satisfying the DCC requirements. The suggested approach was checked on a 11 kV 77-bus active DPS.