A Node voltage violation risk based adaptive partitioning and distributed voltage control method of ADN

High penetration of distributed photovoltaics (PV) aggravates voltage violations in active distribution networks (ADNs). This paper proposes a risk-adaptive partitioning and distributed voltage control method. A risk-adaptive partitioning index is defined for network clustering incorporating a comprehensive performance index combining the regional voltage regulation capability for both overvoltage and undervoltage cases and an improved modularity index. A risk-adaptive double-layer distributed voltage control method with a risk-adaptive penalty mechanism is developed. The risk-adaptive penalty mechanism is introduced into the upper-layer objective function by updating the penalty coefficients of on-load tap changer (OLTC) and capacitor banks (CBs) operations. In the upper layer, the OLTC and CBs are coordinated on an hourly timescale to suppress the voltage violations and minimize active power losses while reducing the mechanical equipment actions. In the lower layer, the controller provides fast intra-partition voltage support and reduces power losses with a control period of 15 min. Simulations on an improved IEEE 123-bus system under different scenarios verify the effectiveness of the proposed method.