Improving area control error diversity interchange (ADI) program by incorporating congestion constraints

The area control error (ACE) determines how much a balancing authority (BA) needs to move its regulating units to meet mandatory control performance standard requirements. Regulation is an expensive resource that could cost several hundred million dollars a year for a BA. The amount of regulation needed in a system is increasing with more intermittent generation resources added to the system. The ACE diversity interchange (ADI) program provides a tool for reducing the regulation requirement by combining ACEs from several participating BAs followed by sharing the total ACE among all participating balancing areas. The effect is achieved as a result of the low statistical correlation between the original ACEs of participating BAs. A rule-based ADI approach has already been put into practice in the US Western Interconnection. The degree of actual ACE sharing is artificially limited because of the unknown redistribution of power flows and possible system congestion (these factors are not monitored in the existing ADI). This paper proposes a two-step linear programming (LP) ADI approach that incorporates congestion constraints. In the first step of the proposed LP ADI, the line transmission limits are enforced by setting up corresponding constraints. In the second step, the business fairness is pursued. Simulation is performed to compare the properties of the proposed LP ADI and the existing rule-based ADI. Favorable features, such as avoiding line limit violations and increasing the degree of possible ACE sharing, are observed for the proposed LP ADI.