The Photovoltaic (PV) hosting capacity of a low-voltage (LV) grid is generally limited by voltage swing issues, and the massive building thermal energy storage can be applied for relieving voltage fluctuations and increasing this capacity. Current voltage control methods (regulators and shunt capacitors) are originally design for conventional grid. New measures like battery storage still face economic controversies. This paper aims to empower air conditioning systems in residential houses for voltage regulation under high PV penetration.
First, two voltage stability issues under high PV penetration condition are revealed by simulation. Then, a temperature priority-based controller is designed for building air conditioning systems, which is categorized as passive thermal energy storage (TES), and a proactive schedule-based controller is designed for active TES – ice storage devices. Finally, A four-node test feeder populated with 360 single-phase PV-equipped residential houses was simulated to illustrate the effectiveness of the two control schemes for voltage regulation. We concluded that demand response (DR) is an effective way for LV grid voltage control. Air conditioning systems can be exploited for voltage control without sacrificing occupant comfort. Active thermal energy storage can effectively increase the DR potentials to regulate the voltage to acceptable levels.
Keywords distribution network, voltage regulation, high PV penetration, thermal energy storage, priority-based control