Advance control of electrical storage units in distribution networks
Event: 13. konferenca slovenskih elektroenergetikov CIGRE-CIRED, Maribor, 22.-24. maj 2017
Increased share of Distributed Renewable Energy Sources (DRES) in the low voltage distribution networks brings the additional solutions and challenges in operation and control of the system. Due to popularity of the DRES, their increased share transformed classic radial configuration of the network towards smart grid oriented situation, with possibility of the reverse power flows. Surplus of locally produced electricity and unpredictable nature of production due to weather conditions, presents additional challenges and problems of the maintaining the power quality parameters within defined limits. An alternative to classic grid reinforcement measures are available, for example, a local installation of a storage unit in the system.
In proposed paper key grid challenges, which occur in distribution systems and could be mitigated with implementation of storage, are described. A multileveled structure of control strategy is proposed, where each level is responsible for separate part of the control strategy. Several use cases of storage implementation are described. The main focus of the paper is the issue of reverse power flows in the distribution network. For the designated demonstration site of residential rural network, a peak demand control, which combines peak shifting and peak shaving activities is described and evaluated through the simulations. Based on analysis of yearly measurements and weather forecast for day ahead interval, the algorithm determines threshold levels, where storage starts operating and charges energy from the surplus of local generation and discharges when necessary.
Keywords: Electrical energy storage technologies, distribution network, peak shaving functionality