Contingency ranking for bulk system reliability criteria

Abstract

One key element of a deterministic bulk system planning criteria is the performance table.The table lists contingencies that planners must examine and sets the minimum acceptable performance level for those events. A basic premise is that lower performance levels, in terms of system impacts, are acceptable for events that are less likely to happen. However, the tables were developed based on planner's experience and intuition, but without a formal framework for their construction. Our focus is to use outage data and models for multiple outages to examine the likelihood of various contingencies. The Bonneville Power Administration revised its criteria based on this analysis.

Development and application of probabilistic criteria in value-based transmission system adequacy assessment

“…The outage probability was computed as a product of the failure probabilities of each of the events. The mathematical models used for computing frequency, duration and unavailability involving two components overlapping independent outages are presented in Equations 2, 3 and 4. λ 12 = λ 1 * λ 2* (r 1 +r 2 )/8760 in occ/year (2) r 12 = r 1* r 2 /(r 1 +r 2 ) in hours (3) U = λ 12 * r 12 / 8760 in per unit (4) Where, λ 12 is the independent overlapping outage frequency of components 1 and 2 λ 1 is the outage frequency of component 1 λ 2 is the outage frequency of component 2 r 1 is the average outage duration of component 1 r 2 is the average outage duration of component 2 U is the unavailability or probability of forced outage of both components 1 and 2.…”

“…Planning and designing of a power system without explicitly considering probability and consequences of contingency occurrence would inevitably render either over or under built power systems. The approach of ranking contingencies based on historical average probability of contingency occurrence in bulk system planning criteria has been considered by some utilities [4].…”

A bounding approach to multiarea probabilistic production costing

“…In general, x would have to account for partial outages, since links often consist of several lines. The partitioning schemes of Section 3 are easily modified to account for this complication, and can be designed to focus on the most important contingencies [17]. Because the GBD model used to calculate the upper bound requires that transmission capacities be fixed and known, each partition must contain no more than a single realization of the transmission state variables.…”

Adequacy Analysis and Security Reliability Evaluation of Bulk Power System

“…The contingency list, which is generally developed based on the planners' experience, is often the result of an informal framework [4]. As power systems become more complex, and unforeseen power flow patterns occur because of independent power producers, the contingency list becomes a less reliable means of assessing the power system reliability because the impact of contingencies absent from the list may become significant [20]. Therefore, the trend is to develop automated procedures for selecting the contingency list by taking into account power flow patterns and new operating scenarios.…”