Dual-Layer Voltage and Var Control for Power Distribution Systems

Introducing distributed generation (DG) in the power distribution system can induce rapid voltage changes due to DG output intermittency. Conventionally, on-load tap changers (OLTCs) and capacitor banks (CBs) are equipped to handle this issue. However, these rapid voltage changes can cause wear and tear in these devices leading to inefficient voltage regulation, reduced equipment lifetime and high operation and maintenance costs. This paper proposes a new dual-layer optimization method to mitigate the rapid voltage changes along with reduced number of device operations and peak demand. The first-layer optimization uses genetic algorithm (GA) to obtain the optimal settings for traditional, mechanical voltage regulating devices and reactive power set points for DGs to reduce the peak load. The second layer determines optimal second-to-second settings of DGs based on a phase level cooperative control method to mitigate fast voltage fluctuations. The multi-hour simulation results show improved voltage profile and reduction in peak demand.