A New Approach on Development of Power System Operational Flexibility Index by Combination of Generation Unit Flexibility Indices

Document Type : Research Article

Authors

1 Electrical engineering department, Amir kabir university, Tehran, Iran

2 Department of Electrical Engineering, Amirkabir University, Tehran, Iran

3 Amirkabir University of Technology

Abstract

Power system flexibility is the ability of power system to cope with the uncertainty and variability of generation and load sides. This ability should be quantified and measured by a suitable index to show the level of system flexibility in different situations. Flexibility area index, proposed by the authors, is a suitable metric for power system flexibility evaluation, especially in the presence of renewable sources as large scale wind and solar farms. Similar to other system flexibility indices, this index is defined first for one generation unit and then, extended to the power system by combination of the unit indices. In this way, an accurate and meaningful combination routine should be established to reflect the effect of each unit flexibility index correctly in the combined system flexibility index. This paper proposes a suitable and justified method to combine the unit flexibility indices, achieving the system flexibility index. The performance of the proposed index is verified by the wind/load curtailment in economic load dispatch incorporated wind power. Achieving this purpose, the mentioned index is decomposed into two components, one for ramp up and maximum generation system capabilities (upper component) and another for ramp down and minimum generation system capabilities (lower component), each related to the load or wind curtailment respectively which is another contribution of this paper. Finally, by establishment of a correlation between upper/lower component and load/wind curtailment, a suitable validity evaluation for the proposed system flexibility index is performed, which is another contribution of this paper.

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