Offering of active distribution network in real-time energy market by integrated energy management system and Volt-Var optimization

This paper considers an active distribution network (ADN) that can benefit from price-responsive demands, inverter-based photovoltaic (PV) generating units, and battery energy storage systems (BESSs) to participate in the real-time energy market. However, a challenging issue arises due to the coupling of energy offerings in the market and Volt-Var schedules of system devices. This paper develops an integrated framework of energy management system and Volt-Var optimization (EMS-VVO) in the ADN. This application is in bidirectional communication with the energy market and electricity assets. In the first stage and some minutes before each hour, the EMS-VVO unit makes the offering decisions in the energy market, as well as the schedules of demands and slow-acting devices (i.e., on-load tap changers (OLTCs) and capacitors) under uncertainties in the market prices, PV power production, and power loads. In the second stage, when the actual values of available PV productions and the updated market prices are known during the power delivery, this application controls the voltage in minutes by dispatching the fast-acting devices (i.e., PV generating units and BESSs) throughout the distribution network in minutes. A number of comparative out-of-sample simulations through a 69-node test system demonstrate how the offering and controlling decisions of the ADN can be modified under different PV penetration levels, voltage violation penalties, demand flexibility levels, and reactive power capabilities of fast-acting devices.