Probabilistic transfer capability assessment in a deregulated environment

Abstract

A methodology for available (simultaneous) transfer capability (ATC) analysis based on a probabilistic approach is presented. It is postulated that the system is operated by an ISO. The traditional concept of "area" is extended to include a utility, an individual IPP, a large customer, etc. All areas are divided into three groups: (a) study area or area under the ISO control, (b) transfer participating areas, and (c) external areas which have no direct transactions or they have fixed transactions with the study area. A performance index based contingency selection procedure is applied within the study and transfer participating areas to rank those contingencies that will affect simultaneous transfer capability. The contingency ranking order is utilized by a variation of the Wind Chime diagram to selected contingencies that are then evaluated by an optimal power flow algorithm. Subsequently, the probability distribution of simultaneous transfer capability is computed based on the electric load, circuit and unit outage Markov models. The 24x3 bus IEEE RTS is utilized to evaluate the proposed method. The performance of the proposed method is also demonstrated on an actual large scale system (2182 bus, 8 area system).

A comprehensive evaluation index system for power system operation

“…It also means that it can maintain this capacity during peak load or with expected or moderately unexpected breakdowns of generation equipment [6][7][8]. Generation capacity adequacy measures the balance risk between the generation capacity and the load demand, and the reliability of the network that connects generation equipment with consumers is infinite.…”

Probabilistic approach to available transfer capability calculation

“…Among these three parameters, TRM is the reserved capacity to account for the uncertainties of network conditions as well as calculation error. It is desirable to properly quantify the uncertainty in the ATC calculation as a safety margin so that the power system will remain secure despite the uncertainties, such as generator/transmission line outages, load deviation and line impedance changes [2][3][4]. CBM is the transfer capability reserved by load serving entities to ensure access to generation from interconnected systems to meet generation reliability requirements.…”

Available Transfer Capability Calculation

“…In the regulated environment, weather factors, load forecast and fault of generators, lines and transformers have most effects on ATC estimation for planning system. Moreover they are increased since the uncertainty in bid acceptance procedures, customer response to prices and control of interruptible loads (Sakis Meliopoulos, Wook Kang, & Cokkinides, 2000). These uncertainties must be quantified for the next few hours by ISO in real time.…”