Coordinated Voltage Regulation Methods in Active Distribution Networks with Soft Open Points

Abstract

This paper proposes a coordinated voltage regulation method for active distribution networks (ADNs) to mitigate nodal voltage fluctuations caused by photovoltaic (PV) power fluctuations, where a three-stage optimization scheme is developed to coordinate and optimize the tap position of on-load tap changers (OLTCs), the reactive power of capacitor banks (CBs), and the active and reactive power of soft open points (SOPs). The first stage aims to schedule the OLTC and CBs hourly using the rolling optimization algorithm. In the second stage, a multi-objective optimization model of SOPs is established to periodically (15 min) optimize the active and reactive power of each SOP. Meanwhile, this model is also responsible for optimizing the Q-V droop control parameters of each SOP used in the third stage. The aim of the third stage is to suppress real-time (1 min) voltage fluctuations caused by rapid changes in PV power, where the Q-V droop control is developed to regulate the actual reactive power of SOPs automatically, according to the measured voltage at the SOPs’ connection points. Furthermore, numerous simulations and comparisons are carried out on a modified IEEE 33-bus distribution network to verify the effectiveness and correctness of the proposed voltage regulation method.