Voltage fluctuation mitigation with coordinated OLTC and energy storage control in high PV penetrating distribution network

Abstract

The surge in the growth of renewable energy resources integration such as solar photovoltaic (PV), wind energy, and tidal energy, etc., is introducing fast fluctuating voltage challenges to the power grid. A battery energy storage system (BESS) can suppress voltage fluctuations up to certain limits that are introduced by intermittency in solar photovoltaic. Although battery energy storage system (BESS) corresponds to faster responses, the lack of coordination between conventional voltage fluctuation mitigation strategies such as On-load tap changer (OLTC) and BESS might lead to an overuse of BESS and underuse of OLTC. This research presents an intelligent and real-time coordinated-control of BESS and OLTC that mitigates the voltage fluctuations, enhances the life of BESS and optimizes the use of existing OLTCs. In the proposed control technique the BESS controls the bus voltage at local level and OLTC controls the voltage at global level. The devised scheme monitors the real-time bus voltages using phasor measurement units (PMU). The scheme assigns respective weights to individual buses that decide the optimal operation of OLTC and BESS. In control of OLTC all the buses are assigned some weights which decide the optimal operation of OLTC and BESS. The proposed scheme is demonstrated on IEEE-13 bus system and results are being compared with the conventional scheme. The proposed control scheme surpasses the voltage regulation by reducing the average voltage violation time to one-fifth compared to conventional control scheme and significant reduction in BESS energy cycle.