An Irradiance Driven Adaptive PQV Droop for Voltage Regulation in Active Distribution System

Abstract

Gradual increasing installation of solar photovoltaic inverters (SPVIs) at the low voltage (LV) network causes over-voltage issue at the SPVI-connected point-of-common-couplings (PCCs). Further, this problem deteriorates the voltage regulation of distribution transformers in active distribution system (ADS) due to high R/X ratio of the lines. To mitigate such issues, IEEE-1547-2020 recommends the constant QV-droop and PV-droop characteristics in the SPVIs. However, due to lack of adaptability of such characteristics with the variable irradiance level, the controller in SPVIs may under-utilize capacity of the SPVIs. In this paper, an irradiance driven adaptive PQV (IAPQV) droop control technique is proposed for the SPVIs to improve the voltage regulation of an ADS as compared to IEEE-1547-2020 recommended droop characteristic. Moreover, a Two-Bit-Priority (TBP) algorithm is proposed for distributed coordination among the SPVIs. During overvoltage situations, the TBP assists in minimizing active power curtailment at the SPVIs. Performance of the proposed method is verified under different scenarios in ADS. The results are validated through MATLAB/Simulink to show that the proposed IAPQV is more effective as compared to the IEEE-1547-2020.