A Metric and Market Construct of Inter-Temporal Flexibility in Time-Coupled Economic Dispatch

The increasing penetration of variable and uncertain generation from renewable resources poses a challenge for balancing the power system supply and demand. Violations of this constraint seriously impact system reliability and thus carry with them a very high cost. In order to address the issues created by variable generation increased system flexibility is required. System operators are considering modifications to the conventional real-time economic dispatch model to provide improved ramp flexibility. In this paper an operational flexibility metric called lack of ramp probability (LORP) is proposed for the real-time economic dispatch. Further, a two-step robust optimization based framework is introduced to simultaneously guarantee LORP flexibility metric and ensure ramp deliverability in a multi-zonal setting. The proposed framework is illustrated on a 3-zone modified IEEE 73 bus (RTS-96) test system.

1. Nomenclature

Index of all buses in the network.

Index of all zones in the network.

Index of all dispatchable generators.

Index of all loads.

Index of all inter-zonal tie-lines.

Index of all intra-zonal transmission lines.

Index of real time dispatch (5 min. intervals).