Distributed Ancillary Services in Smart Distribution Grids: Demand, Requirements and Benefits

The progressing distribution of the electricity supply necessitates redesigning the mechanism for providing ancillary services particularly by the distribution grid. Methods of voltage regulation and congestion management particularly have to satisfy new standards since, although their development of renewables is increasing the number of resources with an impact, these resources' individual contribution is comparatively slight. Taking the current state-of-the-art and the basic regulatory conditions in Germany as its point of departure, this article analyzes the requirements on algorithms and communication systems that provide distributed support to distribution grid operation. A novel mathematical method that prevents voltage range deviations and feeder overloads based on sensitivities is presented and validated in simulations by a case study. An analysis of the communications systems for monitoring and control technologies for distributed energy resources, including the available communication channels, serves the basis for an evaluation of the suitability of current control mechanisms in the future. The findings of a live field test in a real 110 kV distribution grid corroborate the necessity for coordinated grid support by distributed energy resources and demonstrate the limits of current methods.