Home

CEIC-06-11

"Decomposing Congestion and Reliability"
Seth Blumsack, Marija Ilić, and Lester B. Lave

Abstract:
Policy surrounding the North American transmission grid, particularly in the wake of electric-industry restructuring and following the blackout of August, 2003, has treated network congestion and network reliability as if they were separable and independent system attributes. Except for a few special cases, congestion and reliability are not independent, and may not even be separable in any meaningful way. Using the DC power flow model with linear ATC, we provide a method for decomposing a change in network topology into a congestion effect and a reliability effect. We provide analytical expressions describing the topological conditions under which a given network addition or outage will affect congestion and reliability, and prove some sufficiency conditions and some necessary conditions for congestion and reliability to be independent. These include (i) the network is series-parallel; (ii) demand is completely price-inelastic; (iii) all customers value reliability identically; and (iv) the grid operator does not discriminate among customers when forced to physically ration consumption.

PDF's are password protected. If you're a first-time visitor and need a password, please click here.