Critical Bus Voltage Support in Distribution Systems With Electric Springs and Responsibility Sharing

With the development of a new smart load device, the electric spring (ES), the operation of distribution systems with high renewable penetration becomes more flexible. The ESs can be installed at noncritical loads for grid support. This paper proposes a two-level voltage management scheme to optimize the voltage profiles of the network, especially at chosen critical buses. In the upper level, the tap positions of load tap changer and capacitor banks switching are optimized to prevent the voltages along the feeder from being out of limits. The model predictive control technique is applied to handle the uncertainties in renewable energy and demand. In the lower level, the responsibility of maintaining the voltages of the critical buses is shared among the ES in a distributed way via consensus control which is suitable for systems with limited communication and calculation capabilities. The proposed management scheme is verified on a modified IEEE 15-bus distribution network. The results show that different voltage regulation devices can work together to maintain the voltage of critical buses by sharing the responsibility in the proposed scheme.