Power Quality in Smart Distribution Systems with Electric Battery, Large Loads and PV Generation.

Abstract

A change in the electricity consumption is taking place, where one of the main reasons is the large increase in Distributed Generation, as photovoltaic (PV) systems and electric batteries in the low voltage (LV) distribution grid. This could translate in specific cases into a situation of increased peak load and bigger voltage fluctuation. Therefore, an effective control of the grid voltage is necessary to achieve a stable energy supply from renewable sources. What services can a battery provide? The authors present an analysis of voltage control and other battery services in a LV grid. A flexible model based on Python is developed and used to solve a multi-period optimal power flow problem. They propose an optimised distributed voltage regulation. The power flow equations are linearised around a stable operation point, which allows high feasibility and computation speed. Then a receding horizon framework is described, including 24h and 1h updated forecasts. The analysis is performed on a LV network with large loads of a stadium, large PV generation (690kWp) and with a 1MWh battery. The new method provides an optimization of the grid operation (reduced voltage variation and cost of energy imported from the grid) under different seasonal weeks. Index Terms-Battery use, voltage control, complex power, multi-period optimal power flow, receding horizon, low voltage, PV