System Dynamics Model of a Balancing Authority Using Demand Response as Contingent Energy Reserve

Abstract

supply. Since unexpected power generating unit loss or other contingencies directly jeopardize an interconnection’s grid stability, NER C regulations define safety margins in energy reserves that grid operators have to meet in order to assure uninterrupted supply. Such energy reserves are energy inefficient and ero de profits. It has been recently proposed that traditional contingent energy reserves can be augmented by demand response (i.e., load shedding) programs to help meet reliability NERC requirements. In this paper, a new analysis model for capturing the overall dynamic be havior of a Balancing Authority within a control area is developed to assess the effect of l oad shedding on a power grid frequency management program. In contrast to previous approaches that solely use dynamical systems theory based on differential equations, the new app roach uses systems dynamics theory to measure the collective impact of primary, secondary, and demand response systems on frequency control operation performance and cost. The economic part of the Dynamic Systems is based on assumptions about spinning reserves costs and customer bill incentive from load shedding program. A one hour scenario with 20 minutes of power plant generation loss is used as a baseline for running s imulations. For a particular scenario described, both economic and technical performance is seen to improve (with some diminishing returns) as load shedding program parti cipation increases. Results of the systems dynamics approach to modeling are presented and implications are discussed.