Fairness-Oriented Volt–Watt Control Methods of PV Units for Over-Voltage Suppression in PV-Enriched Smart Cities

Abstract

Highlights: What are the main findings? Three conventional and twelve new methods have been evaluated to improve the fair contribution of PV inverters in over-voltage control. The sensitivity of bus voltage to PVs’ active power is identified as the primary key in designing the volt–watt curves. A new scoring method is suggested to evaluate the performance of the studied and proposed methods regarding fairness, curtailment efficiency, and overvoltage control success. What is the implication of the main finding? The proposed methods can be implemented in decentralized and centralized frameworks, depending on the capacity and sophistication of the communication infrastructure in smart cities. The vast majority of methods can prevent the possibility of overvoltage even in very rare low-load conditions. Customer satisfaction is reflected in the performance metrics, while grid stability is also considered. This approach is helpful for smart city planners and utility operators, encouraging them to adopt the proposed methods for integrating high PV penetration. The higher integration of photovoltaic (PV) units is an inevitable component of smart city development. Thanks to smart meter devices that can record the exchange of power between the grid and customers, it is expected that homeowners and businesses will tend to install PV arrays on their rooftops and parking lots to benefit from selling power back to the grid. However, the overvoltage issue resulting from high PV penetration is a major challenge that necessitates the active power curtailment of PV units to ensure power grid stability. Fairness-oriented methods aim to minimize the active power of PV units as much as possible, adopting a fairer approach, and then address the PV owner’s satisfaction with fair profit and loss. Maintaining voltage within a limited standard range under very low load conditions while prioritizing PV inverters’ participation in reactive power contribution and attempting to ensure fairer curtailment of active power presents challenges to existing control design approaches. This paper presents twelve new volt–watt curve design methods to achieve these goals and address the challenges. The methods yield polynomial curves, piecewise linear curves, and single linear curves. A unique voltage sensitivity value for each PV inverter is used to determine the control region area and the slope of the curve at the starting point in certain instances. The effectiveness of the proposed methods is discussed by evaluating their capabilities on the 37-bus IEEE system.