A Novel Approach to DG Curtailment in Rural Distribution Networks – A Case Study of the Avacon Grid as Part of the InterFlex Field Trial

Abstract

Distribution system operators in rural areas of Germany are frequently facing imminent equipment overloading caused by the feed-in of local renewable Distributed Generation (DG). A grid operator's last resort to maintain system stability and avoid protection tripping is to temporarily curtail local feed-in until hosting capacity in the network has caught up with the demand. Due to technological limitations in today's networks the volume of curtailed energy can be greater than what would strictly be necessary. This paper presents a case study of a 110 kV overhead line in Avacon´s network and demonstrates the limitations of today's approach to DG curtailments, especially the relative coarse granularity of control steps. The authors develop a novel control algorithm for emergency curtailments that takes advantage of technological improvements and describes the architecture for a successful deployment at the example of Avacon´s network and SCADA. The authors compare the amount of curtailed energy under today´s best practice with the theoretical optimum and the novel approach.

Forecast of Renewable Curtailment in Distribution Grids Considering Uncertainties

“…In Germany a congestion is resolved by an iterative reduction of the RE in-feed, which shows the highest sensitivity to the current congested component [19]. Due to the applied communication technology this is realized in four levels: 100% of the available power, and 60%, 30%, and 0% in-feed of the installed capacity [20]. In such cases the system has to remain stable, the curtailed energy has to be sufficiently low and the units to be curtailed are chosen non-discriminatory [20].…”

Photovoltaic hosting capacity improvement based on the economic comparison between curtailment and network upgrade

“…Therefore, optimal curtailment analysis can guide and assist the DSO responsible for compensating curtailed PV producers. Curtailment benefits were discussed from DSO's perspective to remove network violations in [15][16][17][18]. Accordingly, the findings of [17] revealed that every kWh decrease in energy curtailment is beneficial, considering savings obtained through reduced compensation.…”

“…Curtailment benefits were discussed from DSO's perspective to remove network violations in [15][16][17][18]. Accordingly, the findings of [17] revealed that every kWh decrease in energy curtailment is beneficial, considering savings obtained through reduced compensation. Moreover, the effectiveness of curtailment was also addressed in [18] to increase the HC using a statistical planning method supporting the fact that a moderate amount of annual curtailment was an attractive substitute for expansion planning.…”