Multi-area Reliability Evaluation Research Articles

Multi-area reliability evaluation including frequency and duration indices with multiple time varying load curves

The reliability evaluation of multi-area systems is part of the expansion planning process of a power system. In order to accurately estimate the system and areas reliability indices, especially the frequency and duration (F&D) indices, the dynamic behavior of system components must be adequately represented with particular attention to the variation of each area load. Nowadays, the most efficient methods for multi-area reliability evaluation do not represent the chronological aspects of the different areas loads. The method that directly considers these aspects is the sequential Monte Carlo simulation, however requiring a high computational effort. This paper presents the application of some methods that represent the chronological aspects of the load to the reliability evaluation of multi-area systems and evaluates their performance and accuracy. The main purpose is to obtain a model for multi-area reliability evaluation that represents the different load curve of each area and accurately estimates the F&D indices. Results obtained by the studied methods are presented for two systems, one composed of two areas and the other based on a representation of the Brazilian interconnected power system with four areas.

Incorporating the DC load flow model in the decomposition-simulation method of multi-area reliability evaluation

This paper presents a computationally viable means of incorporating the DC load flow model in the decomposition-simulation method of multi-area reliability evaluation. The implementation described herein uses a multi-state generation model for each area, a cluster-based multi-area load model which accommodates load correlation between areas, a linear programming model with DC load flow constraints for determining the partitioning states in the decomposition phase, and a similar LP model for determining acceptability of sampled states in the simulation phase. Formulations have been described which enhance the speed and accuracy of the method. The implementation has been tested on 3-area, 4-area, and 5-area cases, and the results obtained have been compared with those produced by an explicit Monte-Carlo simulation. While the results obtained from both methods are similar, the method described has been shown to be considerably faster than explicit simulation.

Incorporation and effects of different supporting policies in multi-area generation system reliability assessment

A new method for multi-area generation system reliability has been developed at the University of Saskatchewan. It is based on direct sampling of generating unit states, clustering and sampling of load states and a linear programming model for multi-area reliability evaluation. Area load uncertainty and correlation can be considered using a correlative distributed sampling technique. Reliability sensitivity indices of both overall system and area to area generation and tie line capacities can be calculated. A wide variety of supporting policies can be easily incorporated in this basic methodology. The authors examine the incorporation of different supporting policies and their effects on multi-area system reliability indices. Case studies of two test systems indicate that different supporting policies create different area reliability indices. It is therefore important to incorporate the supporting policy which is used in actual operation to obtain area indices which are consistent with reality. >

A new algorithm for multi-area reliability evaluation—Simultaneous decomposition-simulation approach

This paper presents a new and efficient approach for including a multi-state load model in multi-area reliability calculations. In the extended decomposition-simulation approach, indices are computed and stored for each load state separately, and then aggregated for all the load states, thus the computation time increases linearly with the number of load states. In the proposed approach, decomposition-simulation is performed for all load states simultaneously. This is achieved by using a modified generation model and a reference load state. The proposed algorithm is shown to be as accurate as the previous one and many times faster.

Improved Algorithms for Multi-Area Reliability Evaluation Using the Decomposition-Simulation Approach

Algorithms are presented for improving the overall effectiveness and efficiency of the decomposition-simulation approach for multi-area reliability evaluation. An algorithm for developing a multi-area load model is first described. This algorithm is based on clustering concepts and captures correlation between area loads. Next, algorithms for simplifying frequency calculations are described. These algorithms provide substantial reductions in the computational time requirement, thus alleviating one of the drawbacks of the decomposition-simulation approach. System studies are presented to demonstrate the relative merits of all the algorithms introduced here. >

Improved algorithms for multi-area reliability evaluation using the decomposition-simulation approach

Algorithms are presented for improving the overall effectiveness and efficiency of the decomposition-simulation approach for multi-area reliability evaluation. An algorithm for developing a multi-area load model is first described. This algorithm is based on clustering concepts and captures correlation between area loads. Next, algorithms for simplifying frequency calculations are described. These algorithms provide substantial reductions in the computational time requirement, thus alleviating one of the drawbacks of the decomposition-simulation approach. System studies are presented to demonstrate the relative merits of all the algorithms introduced here. >

Operating considerations in reliability modeling of interconnected systems-an analytical approach

The authors present an analytical method which can incorporate both operating considerations and interconnection constraints in multiarea reliability evaluation. The model, called OPRINS, is a substantial extension and generalization of concepts contained in a single-area OPCON model and the decomposition-simulation approach for multiarea reliability evaluation. These techniques have been implemented in two computer programs called OPRINS-A and OPRINS-P for the study of interconnected systems operating in 'area' or 'pool' modes for commitment of generating units. Some system studies are described which compare the results obtained from this approach with the comparative sequential simulation models.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Development of a new power reliability criterion for the Swedish Power Pool

A project for the development of a new power reliability criterion for the Swedish Power Pool is described. The new criterion is based on multi-area reliability evaluation software. Calculation of ‘prime power’ for the country as well as for individual utilities is discussed.

A Direct Method for Multi-Area Reliability Evaluation

A Direct Method for Multi-Area Reliability Evaluation

A Direct Method for Multi-Area Reliability Evaluation

This paper describes a model developed for multiarea generation reliability evaluation. It is based on an analytic characterization of the system failure modes, when the interconnected generation is represented by a network flow model. Reliability indices are obtained as functions of each failure mode probability and expected capacity, which are calculated directly by integrating the capacity distribution function over the set that characterizes the failure mode. The dependence of generating capacity on hydrological conditions is explicitly represented. Sensitivity indices of the expected unserved demand with respect to area generation and interconnection reinforcements are also obtained. A case study with a 5-area Brazilian is presented and discussed.