Table 4 Foundational papers in electric-power-supply reliability

A test system for teaching overall power system reliability assessment

R. Billinton; S. Jonnavithula

How does one evaluate overall power-system reliability using an educational test system?

Modeling & Simulation: This paper illustrates how reliability indices can be predicted and provides an overall test system that can be used in graduate or undergraduate settings to illustrate the calculation of these indices.

This paper presents a basic electric-power system network that can be used in teaching overall power-system reliability assessment. The paper introduces the concept of overall assessment, which deals with actual customer levels of service. This is an important requirement in today’s changing utility environment and one that should be stressed in teaching reliability concepts.

Probabilistic evaluation of the effect of maintenance on reliability. An application [to power systems]

J. Endrenyi; G. J. Anders; A. M. Leite da Silva

How does one provide a quantitative connection between reliability and maintenance in power systems?

Quantitative: The component aging process is modeled, and the mean and distribution of the remaining life to failure are predicted for any stage of aging. The method is applied to a practical example.

This paper proposes a probabilistic model for the purpose and describes a computer program based on this model. The model provides a quantitative connection between reliability and maintenance, a link missing in the heuristic approaches.

A reliability-centered asset maintenance method for assessing the impact of maintenance in power distribution systems

L. Bertling; R. Allan; R. Eriksson

How does one assess the impact of maintenance in power-distribution systems?

Quantitative: A systematic approach is presented for investigating the effect of different maintenance strategies. In particular, the authors develop a functional relationship between failure rate and maintenance measures for a cable component.

This paper proposes a method for comparing the effect of different maintenance strategies on system reliability and cost. This method relates reliability theory with the experience gained from statistics and practical knowledge of component failures and maintenance measures. The results show the value of using a systematic quantitative approach to investigate the effect of different maintenance strategies.

Sequential Monte Carlo simulation for composite power system reliability analysis with time varying loads

A. Sankarakrishnan; R. Billinton

How does one assess reliability in a composite generation-and-transmission system?

The authors suggest a sequential Monte Carlo simulation for composite power system reliability analysis with time varying loads. They apply antithetic variates, as a variance reduction technique, to the simulation model to increase its simulation efficiency. They apply an approximate method using a system-load duration curve and an enumeration process to the developed load model and compare the results.

The paper illustrates the development and utilization of an annual chronological load curve for each load bus in a composite generation-and-transmission system and a sequential Monte Carlo simulation approach for composite system-reliability assessment.

Power system reliability I-measures of reliability and methods of calculation

D. P. Gaver; F. E. Montmeat; A. D. Patton

How does one calculate reliability in general power-system networks?

The authors present a probability method that permits important measures of reliability in general power-system networks to be calculated from basic system component data. The reliability of an alternative proposed system can be compared to discover the system yielding the highest reliability or a desired reliability at lowest cost. Important features of the method of the paper include the ability to consider failure bunching caused by storms and outages as a result of component overloading in parallel systems.

This paper presents some basic concepts of the physical significance of various aspects of probability methods as applied to power-system generating-capacity problems. It also discusses the physical meaning and interrelation of various standards of service reliability and the determination of the installed capacity benefits of an interconnection by means of the application of probability method, which can serve as a tool for measuring the reliability performance of an electric-power system, thus providing sound basis for judging when additional facilities are needed.

A Canadian customer survey to assess power system reliability worth

G. Tollefson; R. Billinton; G. Wacker; E. Chan; J. Aweya

How does one quantify the value or benefit of electric-service reliability?

Quantitative: A common approach used in quantifying the value or benefit of electric-service reliability is to estimate the customer costs (monetary losses) associated with power interruptions. Customer surveys are used to determine interruption costs.

The IEEE Power Systems Research Group has conducted surveys of Canadian electric-utility customers in the residential, commercial, and industrial sectors, sponsored by the Natural Sciences and Engineering Research Council and seven participating utilities. This paper presents the overall results of these surveys with emphasis on the cost results.

A security based approach to composite power system reliability evaluation

R. Billinton; E. Khan

How does one evaluate reliability of a composite power system using a security-based approach?

Linear programming model: The authors classify the composite system into different system states and calculate probabilistic indices for each. Using both annualized and annual indices in a seven-step load model of two test systems, the authors detect problem-creating contingencies and present a linear programming model for generation rescheduling and minimization of the amount of load shed.

An electric power network containing generation and transmission facilities can be divided into several states in terms of the degree to which adequacy and security constraints are satisfied in a reliability evaluation of the composite system. The authors present a linear programming model for generation rescheduling and load-shed minimization. A linear programming model for correcting the voltage problem is presented.

Reconfiguration of power distribution systems considering reliability and power loss

B. Amanulla; S. Chakrabarti; S. N. Singh

How does one reconfigure power distribution systems considering reliability and power loss?

Using probabilistic reliability models, the authors evaluate reliability at various load points with an algorithm to find the minimal set of components appearing between the feeder and any particular load point.

The paper develops a power-distribution-system reconfiguration methodology considering the reliability and the power loss. The paper presents the optimal status of the switches to maximize the reliability and minimize the real power loss by a binary particle-swarm-optimization-based search algorithm. The proposed methodology’s effectiveness is demonstrated on 33- and 123-bus radial distribution systems.

An efficient technique for reliability analysis of power systems including time dependent sources

C. Singh; Y. Kim

How does one analyze reliability of electric-power systems with such time-dependent sources as photovoltaic and wind generation?

Analytical model: The authors’ method proposed groups the units into several subsystems. One subsystem contains the conventional units and the remaining subsystems consist of unconventional units. A generation system model is built for each subsystem. The outputs for the unconventional units and the load are treated as correlated random variables. The authors use a clustering procedure to identify states with, for a given value of load, specific mean values of the outputs from the unconventional units.

The paper introduces a method of reliability analysis for electric-power systems with such time-dependent sources as photovoltaic and wind generation. The fluctuating characteristic of unconventional generation units has a different effect on the reliability of the generation system than do conventional units. The paper presents reliability analysis combining the conventional subsystem with the unconventional subsystems in each state and combines the output from all the states to compute the loss of load expectation and expected unserved energy.

A reliability model of large wind farms for power system adequacy studies

A. S. Dobakhshari; M. Fotuhi-Firuzabad

How does one model the reliability of large wind farms for power-system adequacy studies?

The paper proposes a systematic method based on a frequency-and-duration approach to model a wind farm as a multistate conventional unit: The probability, frequency of occurrence, and departure rate of each state can be obtained using the wind farm’s regional wind regime and wind turbine characteristics. The proposed method can find both annual frequency and average time of load curtailment analytically in the presence of wind power. As an example, the paper studies a wind farm in northern Iran with 1 year of wind speed data.

This paper presents an analytical approach to reliability modeling of large wind farms. The results show that seasonal patterns significantly affect the reliability indices. A reliability analysis using a load profile similar to that of Iran’s power network shows that the coincidence of high-load-demand and high-wind-speed periods makes the northern Iran wind-farm projects highly attractive from a reliability point of view. The paper includes reliability analysis considering seasonal patterns of wind speed to accommodate time-varying wind-speed patterns.

Power distribution system planning with reliability modeling and optimization

Y. Tang

How does one plan a power distribution system with reliability modeling and optimization?

Modeling and optimization: The paper models distribution-system reliability in the optimization objective function via outage costs and costs of switching devices, along with the nonlinear costs of investment, maintenance and energy losses of both the substations and the feeders.

Supported by an extensive database, the planning software tool can optimize the power-distribution system of a developing city. The optimization model established is multistage, mixed integer and nonlinear solved by a network-flow programming algorithm. The paper also presents a multistage interlacing strategy and a nonlinearity iteration method.

Cost–benefit analysis of power system reliability: Two utility case studies

E. G. Neudorf; D. L. Kiguel; G. A. Hamoud; B. Porretta; W. M. Stephenson; R. W. Sparks; D. M. Logan; M. P. Bhavaraju; R. Billinton; D. L. Garrison

How does one do cost–benefit analysis of power-system reliability?

A cost–benefit approach that quantifies the reliability benefits of alternatives in terms of the reduction in costs resulting from unserved energy enables the evaluation of generation and transmission capacity additions on a consistent, economic basis.

This approach is applied to two utility case studies. For the Pacific Gas and Electric Company, it was used to evaluate three options for maintaining reliability in a major load center—two involving local generation, and a third employing a new 230 kV transmission connection. For Duke Power Company, the approach was used to evaluate alternative designs for additions to a transmission station.

Frequency and duration methods for power system reliability calculations: I-generation system model

J. D. Hall; R. J. Ringlee; A. J. Wood

How does one evaluate and compute electric-power-system reliability considering the requirement that a consistent technique be used for all portions: generation, transmission, and distribution?

This paper is concerned with the procedure for calculating the availability, frequency, and outage duration for a number of generating units connected in parallel to form a single system.

A reliability-calculation method for the generation system that incorporates the frequency and duration of unit outages and includes consideration of the loads leads to three calculated generation-reliability measures: availability, frequency of occurrence, and mean duration of reserve states. These are cumulative states in that they specify system reserve conditions of a given magnitude or less. Numerical data are used to illustrate the technique and compare with other methods.

Population-based intelligent search in reliability evaluation of generation systems with wind power penetration

L. Wang; C. Singh

How does one assess power-generating systems to ensure proper system operations in the face of various uncertainties including equipment failures?

Mixed method: Four representative population-based intelligent search procedures—genetic algorithm, particle-swarm optimization, artificial-immune system, and ant-colony system—are adopted to search the meaningful system states through their inherent convergence mechanisms. These most-probable failure states contribute most significantly to the adequacy indices including loss-of-load expectation, loss-of-load frequency, and expected unmet demand. The proposed solution methodology is also compared with the Monte Carlo simulation through conceptual analyses and numerical simulations with some qualitative and quantitative comparisons.

Due to the large number of system states involved in system operations, to enumerating all possible failure states to calculate the reliability indices is not normally feasible. Monte Carlo simulation can be used for this purpose through iterative selection and evaluation of system states. However, due to its dependence on proportionate sampling, its efficiency in locating failure states may be low. The simulation may thus take a long time to converge in some evaluation scenarios. This investigation uses a modified IEEE reliability test system is used.

Reliability evaluation of generating systems containing wind power and energy storage

P. Hu; R. Karki; R. Billinton

How does one evaluate the reliability of generating systems containing wind power and energy storage?

The paper presents a simulation technique that can consider wind-farm and energy-storage operating strategies, evaluates different operating strategies are compared and the resulting benefits, and illustrates the system impacts of energy storage capacity and operating constraints, wind-energy dispatch restrictions, wind penetration levels, and wind-farm location on the reliability benefits from energy storage.

High wind penetration can lead to high risk levels in power-system reliability and stability. Maintaining system stability may require wind-energy dispatch restrictions and energy storage to smooth out the fluctuations and improve supply continuity. The benefits from using energy storage are highly dependent on the operating strategies associated with wind and storage in the power system.

System reliability assessment method for wind power integration

F. Vallee; J. Lobry; O. Deblecker

How does one assess system reliability for wind-power integration?

Modeling: A new method, based on a discrete convolution process, to compute a two-state global probabilistic model for wind generation and to define an equivalent capacity for global wind production and introduce it in the predictive peak-load covering process.

It is illusory to imagine that all the installed wind capacity will always be productive. This convolution between each single wind park and multistate histograms permits the accurate computation of equivalent capacity for an entire country’s wind production.

Bibliography on the application of probability methods in power system reliability evaluation

R. N. Allan; R. Billinton; A. M. Breipohl; C. H. Grigg

What has been published on the subject of power-system reliability evaluation?

This paper presents a literature review and bibliography of papers on the subject of power-system reliability evaluation up to year 1999.

Discrete convolution in power system reliability

R. N. Allan; A. M. Leite da Silva; A. A. Abu-Nasser; R. C. Burchett

How does one evaluate power-system reliability?

The paper presents a method for convolving discrete distributions using fast Fourier transforms to evaluate a generating system’s loss-of-load probability and demonstrate the method’s application and inherent merits.

This method can be used in evaluating reliability of any system involving discrete or discretized convolution. It has been used in power-system studies to deduce capacity-outage probability tables and to solve probabilistic load flows. This method is much less time-consuming and more efficient than the conventional direct methods.

Critical component identification in reliability centered asset management of power distribution systems via fuzzy AHP

P. Dehghanian; M. Fotuhi-Firuzabad; S. Bagheri-Shouraki; A. A. Razi Kazemi

How does one determine the most critical component types of power-distribution systems to be prioritized in maintenance scheduling?

A practical case study using the proposed fuzzy analytical hierarchical process method introduces its applicability and efficiency in the asset management.

This paper presents a novel approach on the basis of the analytical hierarchical process accompanied by fuzzy-set theory to determine the most critical component types of power-distribution systems to be prioritized in maintenance scheduling. In the presence of many qualitative and quantitative attributes, fuzzy sets can effectively help to deal with the existent uncertainty and judgment vagueness.

An information architecture for future power systems and its reliability analysis

Z. Xie; G. Manimaran; V. Vittal; A. G. Phadke; V. Centeno

What information architecture should we use for future power systems, taking into account the requirements of real-time data, security, availability, scalability, and appropriate quality of service?

Modeling: Modeling real-time operating and control system with various redundancy configurations facilitates the study of the reliabilities of different configurations and the comparison of practical values of component failure rates and repair rates.

This paper points out the major deficiencies in current communication and information systems and proposes a new power-system information architecture aimed at correcting these deficiencies. The proposed architecture includes automation and control systems at all levels, from substation control system to independent-system-operator operating center. It uses multiple communication channels employing a wide variety of technologies to transmit real-time operating data and control signals.

Incorporating aging failures in power system reliability evaluation

W. Li

How does one incorporate aging failures in power-system reliability evaluation?

This paper uses a calculation approach with two possible probability distribution models to evaluate unavailability of aging failures and implementation reliability. The BC Hydro North Metro system serves as an example to demonstrate an application of the proposed method and models.

The results indicate that aging failures have significant impacts on system reliability, particularly for an “aged” system. Ignoring aging failures in reliability evaluation of an aged power system will result in an underestimation of system risk and most likely a misleading conclusion in system planning.

Bayesian network model for reliability assessment of power systems

D. C. Yu; T. C. Nguyen; P. Haddawy

How does one apply Bayesian networks to resolve the problem of power-system reliability assessment?

A Bayesian-network probabilistic inference algorithm not only permits computation of the loss-of-load probability, but also answers various probabilistic queries about the system. Examples demonstrate the advantages of Bayesian-network models for power-system reliability evaluation.

Results of a reliability case study of a multiarea test system demonstrate that Bayesian networks provide a flexible means of representing and reasoning with probabilistic information, easily incorporating uncertainty and dependencies in the analysis.

Latin hypercube sampling techniques for power systems reliability analysis with renewable energy sources

Z. Shu; P. Jirutitijaroen

How does one conduct reliability analysis of power systems including renewable energy sources, with an emphasis on the fluctuation of bus loads and intermittent behavior of such renewable sources as wind and solar power?

This paper compares Monte Carlo sequential sampling, Monte Carlo nonsequential sampling, and from the proposed Latin hypercube sampling. Two case studies modified from the Electric Reliability Council of Texas and IEEE Reliability Test System demonstrate the proposed sampling methods’ performance.

This paper proposes Latin hypercube sampling methods for reliability analysis of power systems including renewable energy sources, with an emphasis on the fluctuation of bus loads and intermittent behavior of such renewable sources as wind and solar power. The proposed methods are as accurate as the other sampling methods while using much less CPU time.

Evaluating future power distribution system reliability including distributed generation

M. Al-Muhaini; G. T. Heydt

How does one assess the impact of conventional and renewable distributed generation on the reliability of future distribution systems?

Modeling: The paper models and studies the stochastic nature of renewable resources and their influence on the reliability of the system by computing the adequacy transition rate and proposes an integrated Markov model that incorporates the distributed-generation adequacy transition rate, distributed-generation mechanical failure, and starting and switching probability to give accurate results for the distributed-generation reliability assessment.

This paper assesses the impact of conventional and renewable distributed generation on the reliability of future distribution systems, even when the connection may not be simply radial. The technique used appears to be applicable to any renewable energy source.

Frequency and duration methods for power system reliability calculations: ii - demand model and capacity reserve model

R. J. Ringlee; A. J. Wood

What frequency and duration methods can be used for power-system reliability calculations?

Incorporating a model of the power system load with the generation-system model developed previously permits computation of the availability, frequency of occurrence, and mean duration of generation reserve, or margin states. This work illustrates its results with by continuing a simple numerical example.

This paper incorporates a model of the power-system load in the generation-system model developed previously. Previous methods yield only the availability of the reserve margin states, or else availability and frequency data for generating-capacity states without considering the load. The method presented and illustrated may be extended to calculate operating reliability or the inclusion of the effects of a simple transmission system.

Improving power system reliability calculation efficiency with EPSO variants

V. Miranda; L. de Magalhaes Carvalho; M. A. da Rosa; A. M. Leite da Silva; C. Singh

Can one use such population-based methods as evolutionary particle-swarm optimization to evaluate power-system reliability?

This paper uses evolutionary particle-swarm optimization to evaluate power-system reliability. The results obtained are compared to Monte Carlo simulation and other population-based methods.

The work reported in this paper demonstrates that evolutionary particle-swarm optimization’s variants can focus the search to the region of the state space where contributions to the formation of a reliability index may be found, preferable to conducting a blind sampling of the whole space.

Comparison of simulation methods for power system reliability indexes and their distributions

P. Jirutitijaroen; C. Singh

How does one conduct reliability analysis of power systems using discrete the new Latin hypercube sampling technique?

Distributions of reliability indexes resulting from two sampling techniques are presented and analyzed along with those from Monte Carlo sampling. The distributions of indices are useful in risk analysis and certain stochastic optimization problems. The test system is a 12-area power system based on the data from an actual multiarea system.

This paper investigates Latin hypercube sampling in connection with power-system reliability evaluation, proposes a new sampling technique called discrete Latin hypercube, and compares distributions of reliability indexes resulting from the two sampling techniques with those from Monte Carlo sampling. The Latin-hypercube-based techniques are more effective than Monte Carlo for obtaining distributions of indices close to the real distributions.

A new approach to reliability evaluation of interconnected power systems including planned outages and frequency calculations

Z. Deng; C. Singh

How does one evaluate reliability of interconnected power systems while including planned outages and frequency calculations?

Modeling and simulation: The paper simultaneously considers state space over all maintenance intervals and load states by using the concept of a reference load state and an equivalent composite-generation model and performs a decomposition-simulation procedure on this state space. This facilitates the development of a very fast algorithm and efficient storage.

The authors present an approach for reliability evaluation of interconnected power systems. In addition to the loss-of-load probability and expected unmet demand, the loss-of-load frequency can be computed efficiently. This approach can very efficiently include generating units’ planned outages. Sample studies are presented to show that this algorithm is as accurate as the previous one but many times faster.

Power-system reliability in perspective

R. Billinton; R. N. Allan

What are the philosophical aspects concerning power-system reliability?

This paper presents a literature review and discussion of quantitative reliability evaluation, data available, and data required to support such analysis.

This article discusses several philosophical aspects concerning power-system reliability, putting the reliability aspects in perspective and describing a hierarchical framework of analysis to discusses how the economics of reliability should be compared.

Power system reliability impact of energy storage integration with intelligent operation strategy

Y. Xu; C. Singh

What is the impact of energy-storage integration on power-system reliability?

The authors perform a detailed case study and sensitivity analysis to demonstrate the effectiveness of the presented operation strategy and evaluation framework, and to provide valuable insights on the power-system-reliability impact derived from the integrated energy storage.

In this paper, the focus is on reliability improvement in the bulk-power system brought about by the use of energy storage in local distribution systems integrated with renewable-energy generation. The authors present an intelligent operation strategy for energy storage that improves reliability considering the renewable-energy integration.

Generation/​transmission power system reliability evaluation by Monte-Carlo simulation assuming a fuzzy load description

J. Tome Saraiva; V. Miranda; L. M. V. G. Pinto

How does one evaluate Generation/​transmission-power-system reliability by Monte-Carlo simulation assuming a fuzzy load description?

This methodology samples states according to the probabilistic models governing the lifecycle of system components and uses fuzzy concepts to model uncertainty related to future load behavior. This model can be used to evaluate generation/​transmission-power-system reliability for long-term planning studies as one uses the more adequate uncertainty models for each type of data.

This paper presents a Monte-Carlo algorithm considering loads defined by fuzzy numbers, proposes new indices reflecting the integration of probabilistic models and fuzzy concepts, and discusses the application of variance reduction techniques where loads are defined by fuzzy numbers. A case study based on the IEEE 30 bus system illustrates this methodology. Each sampled state includes a fuzzy optimal power flow so that one builds its power on supplied membership function.

Static and dynamic aspects in bulk power system reliability evaluations

A. M. Rei; A. M. Leite da Silva; J. L. Jardim; J. C. O. Mello

How does one evaluate bulk-power-system reliability considering both static (adequacy) and dynamic (security) consequences of disturbances that may occur in electric-power systems?

Modeling and simulation: The assessment of dynamic aspects requires the modeling of protection systems, control actions, and restoration processes. The cascading effects associated with dynamic problems are usually non-Markovian in nature, so they are better modeled through a Monte Carlo chronological or sequential simulation. The paper uses method combining time simulation and transient energy function for the transient stability analysis.

This work extends the concepts and evaluation techniques for composite-generation and transmission-reliability assessment to provide performance measures considering both static (adequacy) and dynamic (security) consequences of disturbances that may occur in electric power systems. An extended IEEE-Reliability Test System, bearing in mind static and dynamic aspects, tests the proposed methodology. Loss-of-load probability measures adequacy and security. They are also decomposed to capture the contributions of various failure types considered: phase faults, etc.

Power system reliability enhancement using a thyristor controlled series capacitor

R. Billinton; M. Fotuhi-Firuzabad; S. O. Faried

What is the impact of a thyristor-controlled series capacitor on power-system reliability?

Modeling and application: The paper presents a reliability model of a multimodule thyristor-controlled series capacitor incorporated in a transmission system.

This paper examines the impact of a thyristor-controlled series capacitor on power-system reliability. This application employs a thyristor-controlled series capacitor to adjust the natural power sharing of two different parallel transmission lines and, therefore, enable the maximum transmission capacity. The results of the investigations show a significant improvement in system reliability. The improvement is measured using two indices: loss-of-load expectation and loss-of-energy expectation.

Evaluation of power systems reliability by an artificial neural network

N. Amjady; M. Ehsan

How does one evaluate power-system reliability with an artificial neural network?

The authors base this method on the artificial neural networks that require short training times.

The paper presents a new method for reliability analysis of power systems, which can solve difficulties of the previous reliability-analysis methods, such as low accuracy, complex modeling, and large computations. The proposed artificial neural network evaluates generating-unit and transmission-system reliability. Obtained results from this method for the IEEE reliability test system confirm the validity of the developed approach.

Impact of unified power flow controllers on power system reliability

R. Billinton; M. Fotuhi-Firuzabad; S. O. Faried; S. Aboreshaid

What is the impact of unified-power flow controllers on power system reliability?

Analytical approach: Improvement is measured using three reliability-risk indices: the loss-of-load expectation, the loss-of-energy expectation, and system minutes. The paper also compares the effects of the unified-power flow controller and a thyristor-controlled series capacitor on the system reliability.

This paper examines the impact of a unified power flow controller on power-system reliability. The system employs the unified-power flow controller to adjust the natural power sharing of two different parallel transmission lines, facilitating use of the maximum transmission capacity. The results show a significant improvement in system reliability.

Reliability assessment of a restructured power system considering the reserve agreements

P. Wang; R. Billinton

How does one evaluate the customer-load-point reliability in a deregulated power system considering customer choice?

Analytical approach: In this technique, an equivalent multistate-generation provider and an equivalent multistate reserve provider represent a generation company (genco), based on the market function of a genco. An equivalent multistate generation provider with reserve agreements, which has reserve agreements with other gencos, represents a genco. An equivalent multistate transmission provider with reserve agreement represents the transmission system between a genco and its customers, considering reserve agreements.

This paper presents a technique to evaluate the customer load point reliability in a deregulated power system considering customer choice on reliability. Reliability-network-equivalent techniques are extended and combined with the equivalent-assisting-unit approach to determine the reliability model of the equivalent multistate generation provider with reserve agreement. The paper also develops a procedure used to determine the reliability model of equivalent multistate transmission provider with reserve agreement. The IEEE reliability test system is used to illustrate the techniques.

Bibliography on the application of probability methods in power system reliability evaluation

R. Billinton

What has been published on the application of probability techniques in the evaluation of power-system reliability up to 1972?

A literature review and a presentation of a bibliography of papers on the subject of the application of probability techniques in the evaluation of power-system reliability (up to year 1972)

This bibliography deals with the application of probability techniques in the evaluation of power-system reliability, but it does not contain all the material available on this subject. The many excellent publications clearly indicate the increasing use and interest in the application of probability methods in the evaluation of power-system reliability.

Unreliability cost assessment of an electric power system using reliability network equivalent approaches

P. Wang; R. Billinton; L. Goel

How does one evaluate the customer-load-point unreliability cost caused by outages in different segments of the power system?

Analytical approach: This paper uses reliability-network-equivalent techniques to evaluate the customer-load-point unreliability-cost indices caused by outages in different segments of the power system. The percentage distribution of unreliability costs for system segments reveals the system’s weak segments. A test system illustrates the application of these techniques.

Unreliability-cost evaluation of an entire power system provides a set of indices that can be used by a system planner to balance investments in different segments of the system and provide acceptable load-point reliability.

Impact of WAMS malfunction on power system reliability assessment

F. Aminifar; M. Fotuhi-Firuzabad; M. Shahidehpour; A. Safdarian

What is the impact of situational awareness and controllability on power-system reliability assessment?

Modeling and simulation: The paper proposes a methodology to simulate a situation in which a limitation of either or both monitoring and control functions could spread the consequence of power-system events throughout the grid.

The monitoring and control infrastructure is assumed to be based on a wide-area measurement system. Monte Carlo simulation and a scenario reduction technique help overcome computational burdens on 9-bus and IEEE 57-bus systems.