Enhancing Distribution System Reliability via Volt/VAr Regulation and Stability-Constrained Adaptive Inverter Control

This paper proposes a stability-constrained adaptive operation strategy for inverter Volt/VAr controls to improve the reliability of active distribution systems—i.e., distribution systems integrated with inverter-based resources (IBRs). The proposed strategy exploits the ability of IBRs to function in a manner similar to advanced Volt/VAr regulators, offering enhanced flexibility in voltage regulation. This paper shows how this strategy can reduce service interruptions resulting from voltage regulation problems. To quantify the impact of the proposed strategy on improving distribution system reliability, this paper also develops a reliability assessment method that models inverters with the proposed control strategy. The proposed reliability assessment method captures the interdependency between the system reliability and Volt/VAr regulation facilitated by the stability-constrained adaptive control of IBRs, and thereby enables the quantification of the reliability enhancement provided by the proposed IBR operation strategy. The proposed Volt/VAr control strategy and the reliability assessment method are applied to the IEEE 33-node test system. The stability constraints of the adaptive control are rigorously defined and developed through eigenvalue stability analysis, ensuring robust and reliable operation of the proposed control system. The results show that effective voltage regulation improves the continuity of service to customers. A comparison study of the proposed operational optimization on adaptive inverter controlling systems against two conventional inverter control strategies demonstrates a notable improvement in the duration of service interruptions, highlighting its effectiveness in enhancing system reliability.