A Two-Stage Conservation Voltage Reduction Technique in Multi-Energy Systems with PV Smart Inverters

This paper proposes a novel two-stage stochastic Conservation Voltage Reduction (CVR) technique in integrated electricity and natural gas systems, where the mixed-integer second-order cone programming (MISOCP) model is used to coordinate the legacy voltage regulation equipment (on-load tap changers (OLTCs) and capacitor banks (CBs)) with photovoltaics (PV) smart interfacing inverters. In the first stage, optimal hourly day-ahead settings of OLTCs and CBs, and the base reactive power settings of PV inverters are determined. After considering uncertainties in the forecasted load and PV power generation, reactive power adjustments from inverters through droop control are determined in the second stage. In addition, a two-step algorithm is proposed to improve the solving speed of the stochastic problem. The proposed stochastic CVR technique is validated using the modified IEEE 33-bus electricity and 7-node natural gas test system, showing its effectiveness on energy savings and loss reductions.