Multi-Time-Scale Optimal Voltage Control in Microgrids with Distributed Generations

Aiming at the problems of network loss increase, voltage deviation, and voltage exceeding specified limits when large-scale distributed generations (DGs) are connected to a microgrid (MG), this paper proposes a multi-time scale coordinated control method considering different types and response speeds of reactive power regulation equipment. In the day-ahead stage, an optimization model is established to minimize the network loss and voltage deviation by controlling traditional equipment like tap changers and capacitor banks, which is efficiently solved by linearization and a second-order cone algorithm. In the real-time stage, a reactive power-voltage control model based on the voltage sensitivity principle is proposed, which considers the differences in the adjustment costs of different DGs. The simulation example shows that the proposed method reduces the voltage deviation and network loss (by 34.73<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">%</sup>). For voltage regulation, it can optimize the regulation target according to the voltage sensitivity and the regulation costs of each DG, thus resulting in better economic performance while adjusting voltages.