Techno-Economic Analysis of PV Inverter Controllers for Preventing Overvoltage in LV Grids

Voltage-rise due to increasing installation of photovoltaic (PV) systems is a major technical issue in low voltage (LV) distribution networks. A cost-effective approach to address the overvoltage problem is to control the active and reactive power of the existing PV inverters. This paper describes the use of quasi-steady-state time-series (QSTS) software (GridLAB-D) to implement inverter overvoltage prevention strategies, allowing previously infeasible long-term techno-economic analysis of such controllers. Four PV inverter controllers are implemented to evaluate the long-term technical and economic impact on a 12-house LV distribution network. Results quantify PV energy curtailment, distribution system losses, and the impact on electric utility sales and government taxes. Droop methods were shown to be effective to avoid overvoltage, and the use of reactive power reduced PV curtailment by 2-3 times over similar methods that only curtail active power. In addition, the difference between using local (no communication) and a comparable method with communication was shown to be insignificant to justify the additional investment. This work can aid utilities to decide the most effective control and pricing methods, and whether investments in overvoltage prevention infrastructure can be justified under high PV penetration scenarios.