A multilevel overvoltage prevention strategy for the distribution networks with high penetration of rooftop photovoltaic systems

The high penetration of rooftop photovoltaic systems (RPSs) causes the overvoltage issues in the low-voltage distribution networks (LVDNs). This paper proposes a multilevel overvoltage prevention strategy to solve the assigned issues. The proposed strategy consists of three levels. An optimal approaching method is adopted at the primary level to minimize the total curtailed active power in the LVDNs. An economy sensitive equalization method is employed at the secondary level to equalize the curtailed active power of each RSP. A comprehensive reactive power regulation method is utilized at the tertiary level to minimize the curtailed active power of each photovoltaic (PV) inverter. Above advanced methods are implemented by the cooperation of voltage management agents. The effectiveness and efficiency of the proposed strategy are validated by a demonstration project in Nanjing, China. The test results show that the proposed strategy decreases the curtailed active power in the LVDNs and avoids the risk of uneconomical and unallowable operation for the PV inverters. The application of the proposed strategy enhances the reliability and economy of the LVDNs with high penetration of RPSs.