Showing papers on "Forced outage published in 2014"
TL;DR: In this paper, a probabilistic model for generation and transmission expansion planning (G&TEP) problem considering reliability criteria is described, which considers the installation and operation costs as well as the cost of expected energy not supplied (EENS) to optimally determine the number and location of new generating units and circuits in the network.
Abstract: This paper describes a new probabilistic model for generation and transmission expansion planning (G&TEP) problem considering reliability criteria. Probabilistic reliability criteria accounts for random generator or line outages with known historical forced outage rates (FOR). The resultant model considers the installation and operation costs as well as the cost of expected energy not supplied (EENS) to optimally determine the number and location of new generating units and circuits in the network, power generation capacity for those units and the voltage phase angle at each node. Also, efficient linear formulations are introduced in this paper to deal with the nonlinear nature of the problem including objective functions and constraints. Modified 6-bus test system, IEEE 24-bus RTS and IEEE 118-bus test system are utilized to illustrate the effectiveness of the proposed framework.
160 citations
TL;DR: This work combines the optimized dispatch from the dynamic program with estimated system loss of load probabilities to compute a probability distribution for the state of charge of storage in each period, which can be used as a forced outage rate for storage in standard reliability-based capacity value estimation methods.
Abstract: We present a method to estimate the capacity value of storage. Our method uses a dynamic program to model the effect of power system outages on the operation and state of charge of storage in subsequent periods. We combine the optimized dispatch from the dynamic program with estimated system loss of load probabilities to compute a probability distribution for the state of charge of storage in each period. This probability distribution can be used as a forced outage rate for storage in standard reliability-based capacity value estimation methods. Our proposed method has the advantage over existing approximations that it explicitly captures the effect of system shortage events on the state of charge of storage in subsequent periods. We also use a numerical case study, based on five utility systems in the U.S., to demonstrate our technique and compare it to existing approximation methods.
150 citations
27 Jul 2014
TL;DR: A Bayesian attack graph model is used to evaluate the probabilities of successful cyber attacks on the SCADA system, which will result in breaker trips and the loss of load probabilities in reliability test system 79 (RTS79) are estimated.
Abstract: As information and communication networks are highly interconnected with the power grid, cyber security of the supervisory control and data acquisition (SCADA) system has become a critical issue in the power system By intruding into the SCADA system via the remote access points, the attackers are able to eavesdrop critical data and reconfigure devices to trip the system breakers The cyber attacks are able to impact the reliability of the power system through the SCADA system In this paper, six cyber attack scenarios in the SCADA system are considered A Bayesian attack graph model is used to evaluate the probabilities of successful cyber attacks on the SCADA system, which will result in breaker trips A forced outage rate (FOR) model is proposed considering the frequencies of successful attacks on the generators and transmission lines With increased FOR values resulted from the cyber attacks, the loss of load probabilities (LOLP) in reliability test system 79 (RTS79) are estimated The results of the simulations demonstrate that the power system becomes less reliable as the frequency of successful attacks increases
14 citations
TL;DR: In this paper, the joint probability density function (PDF) of the wind power and the forced outage rate of aggregated wind power are derived for small-scale siting analysis, where the fluctuations of wind power production affect the capacity value or the size of energy storage.
9 citations
07 Jul 2014
TL;DR: In this article, the authors proposed an analytical method to calculate the capacity credit of wind farms including the mechanical failure of wind turbines, which is based on the discrete convolution technique and takes into account the stochastic nature of wind power as well as the forced outage rates (FOR) of wind turbine.
Abstract: In view of the increasing role of wind power generation, there is an evolving body of reliability methods that are concerned with improved modeling of wind generation and related phenomena. An important consideration in the planning of wind generation projects is the capacity value of the farm at the proposed location. The modeling considerations in this process should take into account not only the variable nature of wind and the mechanical failure of turbines, but also the correlation between the individual turbines on the farm. This paper introduces an analytical method to calculate the capacity credit of wind farms including the mechanical failure of wind turbines. The proposed method is based on the discrete convolution technique and takes into account the stochastic nature of wind power as well as the forced outage rates (FOR) of wind turbines. The discrete convolution method has been used in this work to build a generation model in the form of a capacity outage probability table (COPT). A comparison of wind power capacity credit with and without considering the mechanical failures of wind turbines is shown to demonstrate the impact of turbine failure. Also, the capacity credit is calculated based on two reliability indices which are Loss of Load Expectation, LOLE, and Loss of Energy Expectation, LOEE. The proposed method is applied on the IEEE RTS-79 and the hourly wind speed data were taken from Abee Agdm Alberta, Canada. The results show the importance of inclusion of FOR of wind turbines on estimating wind power capacity credit. The results are validated using Monte Carlo simulation.
8 citations
07 Jul 2014
TL;DR: In this article, the authors proposed a method to estimate the contribution of wind farms to power system adequacy (their capacity value) based on Monte Carlo simulation in a unit-commitment model.
Abstract: This paper proposes a method to estimate the contribution of wind farms to power system adequacy (their capacity value) based on Monte Carlo simulation in a unit-commitment model. The proposed method considers stochastic variables such as wind power generation and the forced outage of generating units, and is capable of evaluating the impact of operational constraints (such as transmission congestion, time-coupling constraints of thermal generating units, and unit commitment criteria) in the capacity value of wind. The proposed method is applied to a couple of future wind farms in the Chilean Central Interconnected System and the capacity value results are compared with those obtained by the method suggested by the IEEE-PES Task Force on the Capacity Value of Wind Power. Although both methods showed capable of properly capturing the influence of the correlation between load and wind generation, the proposed method could also capture the impact that transmission congestion and other operational aspects have on the capacity value of wind farms.
5 citations
TL;DR: In this paper, the reliability model of wind generators and the model of transmission network are combined by considering the sequential and autocorrelation of wind speed, the output power function and the forced outage of wind units.
Abstract: Because wind energy fluctuates randomly, the output power of wind turbine generators is uncertain. The reliability of power systems including wind generation is analyzed in this paper. In this paper, the reliability model of wind generators and the model of transmission network are combined by considering the sequential and autocorrelation of wind speed, the output power function and the forced outage of wind units. Then a reliability evaluation model of generation and transmission system, in which the system security constraints are satisfied, is built and the objective function is LSC. Taking IEEE-RTS96 system as an example, the reliability index which can reflect the effects of wind farms is calculated. The result provides the scientific reference for connecting wind farms to power systems.
4 citations
24 Mar 2014
TL;DR: In this paper, the equivalency between renewable and conventional capacities and their contribution on generation reliability is investigated by using the concept of effective capacity, which has two definitions: effective capacity can be computed from generation capacities of renewable and traditional power plants as well as effective load carrying capability.
Abstract: The equivalency between renewable and conventional capacities and their contribution on generation reliability are investigated by using the concept of effective capacity, which has two definitions. The effective capacity can be computed from generation capacities of renewable and conventional power plants as well as effective load carrying capability. Forced outage rate, generation capacity, and number of renewable units are varied to reflect operation behavior of renewable power plant. Loss of load probability is considered as generation reliability index. A small test model consists of three conventional units with an addition of a unit of interest.
3 citations
Journal Article•
TL;DR: In this paper, an output model of battery energy storage system is proposed considering the charging and discharging constraints, capacity constraints and forced outage rate of the battery energy store. And then combining the proposed output models, the integrated model of wind farm can be proposed based on different scheduling strategies of wind farms.
Abstract: The output model of wind farm is proposed taking account into the time-varying characteristics of failure rate and derating rate for wind turbines and the complex wake effects of wind farm. The output model of battery energy storage system is proposed considering the charging and discharging constraints, capacity constraints and forced outage rate of the battery energy storage. And then combining the proposed output models, the integrated model of wind farm can be proposed based on different scheduling strategies of wind farms. According to the integrated model, the risk assessment processes and methods are given. The calculation and analysis of improved IEEE-RTS 79 case was carried out, and the simulation results verify the effectiveness of the proposed model and the method.
3 citations
Patent•
06 Aug 2014
TL;DR: In this article, a wind power plant reliability modeling method with weather conditions taken into account is presented, which comprises the steps of initializing parameters, generating an hourly wind speed sequence of all wind power plants, calculating an hourly output power sequence during normal operation of all the wind generation sets in each wind power power plant, and establishing a multi-state model of all of the wind energy plants.
Abstract: The invention provides a wind power plant reliability modeling method with weather conditions taken into account. The method comprises the steps of initializing parameters, generating an hourly wind speed sequence of all wind power plants, calculating an hourly output power sequence during normal operation of all wind generation sets in each wind power plant, generating an hourly weather condition sequence of each wind power plant, generating an hourly operation state sequence of all the wind generation sets in each wind power plant, generating an hourly output power sequence of all the wind generation sets in each wind power plant, generating an hourly output power sequence of all the wind power plants, and establishing a multi-state model of all the wind power plants. Due to the fact that factors such as the correlation of the weather conditions of the multiple wind power plants, the influence of the weather conditions on the forced outage rate of the wind power plants and the related outage of the wind power plants under poor weather conditions are taken in account at the same time, the wind power plant model established through the method meets practical situations better.
3 citations
Patent•
19 Nov 2014
TL;DR: In this paper, the authors proposed a fast wind power capacity reliability calculating method based on a reliability function, which comprises the following steps: 1) acquiring capacity and forced outage rate of each generator unit in an electrical power system; 2) calculating a unit outage capacity table in the electrical power systems; 3) calculating the reliability function of the system; 4) acquiring a hour-class load curve in an assessment target year, a total installed capacity of a wind farm in the electric power system, and a hour class wind power output curve in the assessment target years; 5) setting an
Abstract: The invention relates to a fast wind power capacity reliability calculating method based on a reliability function. The fast wind power capacity reliability calculating method comprises the following steps: 1) acquiring capacity and forced outage rate of each generator unit in an electrical power system; 2) calculating a unit outage capacity table in the electrical power system; 3) calculating the reliability function of the system; 4) acquiring a hour-class load curve in an assessment target year, a total installed capacity of a wind farm in the electrical power system, and a hour-class wind power output curve in the assessment target year; 5) setting an initial value of wind power capacity reliability; 6) calculating a weighting factor for each hour; 7) calculating wind power capacity reliability in current iteration; 8) according to a wind power capacity reliability result obtained in the current iteration and a capacity reliability result in last iteration, judging whether the iteration is convergent, if so, determining that the current iteration is the wind power capacity reliability result, otherwise, returning to the step 6). The fast wind power capacity reliability calculating method is relatively small in calculation error; by the fast wind power capacity reliability calculating method, the wind power capacity reliability can be accurately calculated in various electrical power systems and under various wind power conditions.
01 Jan 2014
TL;DR: In this article, a model of transmission lines de-icing optimal scheduling was proposed to reduce the system risk during the ice storm, where the ice and wind loads on lines could be calculated by weather and icing forecast.
Abstract: A model of transmission lines de-icing optimal scheduling was proposed in this paper to reduce the system risk during the ice storm. The ice and wind loads on lines could be calculated by weather and icing forecast. The time-variable forced outage rates of lines could be calculated by the load-strength interference model and it was the component outage model to evaluate the system risk during the ice storm. Considering the ice thickness constraints and system operating level, a dynamic 0-1 integer optimization problem for transmission lines de-icing scheduling, which was with the variables of lines de-icing outage scheme and the objective function of minimizing the value of expected energy not supplied, was proposed and the genetic algorithm was used to solve the programming problem. The proposed model was tested on the IEEE-RTS, and two cases of empirical de-icing scheme were designed to compare with the de-icing scheduling solution solved by the proposed model. The results indicate that under the premise that all three cases guarantee lines' safety, the proposed model gives an appropriate de-icing scheme with minimum system risk. This model can be used as a tool to develop the de-icing scheme before the ice storm.
07 Jul 2014
TL;DR: A specific optimization method is developed which takes into account a forecasted scenario and a stochastic scenario and is applied to the IEEE RTS 24-bus system to investigate the effect of each source of uncertainties on the cost of energy and security controls.
Abstract: The management of uncertainties is a challenging task for reliable and secure operation of power systems. The uncertainties come from multiple sources, including the forecast errors of wind power and load, the forced outage of generating units, loss of transmission equipments, etc. This paper classifies different uncertainties based on their binary and continuous attributes. The main idea is to investigate the effect of each source of uncertainties on the cost of energy and security controls. For this purpose, a specific optimization method is developed which takes into account a forecasted scenario and a stochastic scenario. This optimization problem is solved for a fixed forecasted scenario and a varying stochastic scenario. The stochastic scenarios are constructed using a Monte Carlo Simulation that considers various sources of uncertainties. The main advantage of the proposed optimization is that the number of incorporated stochastic scenarios does not increase the size of the optimization problem. The models of different uncertainties, particularly wind power forecast errors, are discussed in depth. This optimization allows obtaining the statistical moments and constructing the probability distributions. The proposed optimization approach is then applied to the IEEE RTS 24-bus system. The probability distributions and statistical moments of objective functions and control variables are assessed for three cases, namely: (i) with only binary uncertainties, (ii) with only continuous uncertainties and (iii) with both of them.
Patent•
03 Dec 2014
TL;DR: In this article, the utility model provides a switch protection device including an output and input module, a protection control unit and a power module, where the output and inputs are connected with the power module.
Abstract: The utility model provides a switch protection device including an output and input module, a protection control unit and a power module, wherein the output and input module and the protection control unit are connected with the power module; the protection control unit is used for circuit protection of a load switch; the output and input module is used for displaying current state of a circuit and/or inputting parameters into the protection control unit; and the power module is used for providing power for the output and input module and the protection control unit. Therefore, joint forced outage of a faultless line is reduced, forced outage range is reduced, and power failure period is shortened, so that power supply reliability is improved.
28 Jul 2014
TL;DR: In this paper, the authors proposed a mixed weibull approach, where each subpopulation distribution comes out from a single dataset, which represents a step forward after the traditional 2P and the more conservative 3P.
Abstract: When an RBD is required, Failure distribution and Outage distribution are requested as inputs for each block.Should field data exist, the two distributions can be obtained by managing data in the most appropriate manner. While the Failure distribution is often a right censored data set, the outage distribution is always a time-to-failure distribution obtained through the RRX interpolation. Moreover, being the reliability approach conservative, the weibull 3P assumption is welcome, because the gamma value, in this particular circumstance, guarantees a minimum outage duration. However it has been noticed that while the 2P sometimes could be not-conservative enough, the 3P could result too much conservative with the risk of declaring a lower target than the actual one and hence with the consequence of not being commercially competitive. The proposed approach applies and develops the mixed weibull application, where each subpopulation distribution comes out from a single dataset, which represents a step forward after the traditional 2P and the more conservative 3P.Copyright © 2014 by ASME
01 Jan 2014
TL;DR: In this paper, the authors investigated the effect of reliability worth in the optimal economic operation of a small autonomous power system (SAPS) that is based on RES technologies, considering different scenarios.
Abstract: The analysis and design of a small autonomous power system (SAPS) that contains renewable energy sources (RES) technologies can be challenging, due to the large number of design options and the uncertainty in key parameters. Renewable power sources add further complexity because their power output may be intermittent, seasonal, and nondispatchable. Due to this characteristic, reliability evaluation of a RES based SAPS cannot be implemented using the traditional deterministic and analytical methods. Moreover, in order to be complete, this evaluation has to be done within a cost-benefit framework. This chapter investigates the effect of reliability worth in the optimal economic operation of SAPS that is based on RES technologies, considering different scenarios. The optimization procedure is implemented with a combined genetic algorithm (GA) and local search procedure. In addition, this chapter examines the effect of considering SAPS components forced outage rate in the obtained optimal solutions via Monte Carlo simulation (MCS). The performance of the proposed optimization methodology is studied for a large number of alternative scenarios via sensitivity analysis, which study the effect on the results due to the uncertainty on weather data and cost data. The results show that the optimal operation of a RES based SAPS depends largely on the consideration of reliability worth as well as the inclusion of components forced outage rate.
TL;DR: In this article, a new methodology is presented to find the optimal rate of forced outage rate (FOR) of all the components in a power system and the system reliability is assessed and evaluated from view of FOR.
Abstract: Determining the optimal forced outage rate (FOR) ofcomponents can lead to reducing the operational and maintenance costs inelectric power systems. FOR is closely associated with two factors: number ofoutages and duration of outages. Therefore, it is possible to decrease the FORthrough decreasing the number of outages or reducing the duration ofoutages. Decreasing number of outages is usually carried out throughreinforcement of the network and reducing the duration of outages is mainlyperformed through increasing the repair and maintenance groups. Both of theproposed methods to decrease the FOR possess the costs. Therefore, it is verysuitable to find the optimal rate of FOR and avoiding unnecessary costs. Thispaper presents a new methodology to find the optimal rate of FOR. In thisregard, the system reliability is assessed and evaluated from view of FOR andthe optimal rate of FOR is denoted for all components.
TL;DR: In this paper, the authors defined the peak-load regulating demand continuous curve and proposed the calculation method of the peaking gap based on non-sequential Monte Carlo simulation method.
Abstract: An important factor affecting the integration of large-scale wind power is whether there is sufficient peaking capacity. If the peaking capacity is insufficient, we cannot make full use of wind power. Therefore it’s of great significance to study the peaking gap of the power system. This paper defined the peak-load regulating demand continuous curve and proposed the calculation method of the peaking gap based on non-sequential Monte Carlo simulation method. Taking wind power’s random fluctuation and the unit forced outage rate into consideration, the calculation method effectively reflect the peaking capacity needs of the system, which is helpful for determining the appropriate wind power integration.
28 Jul 2014
TL;DR: In this paper, Thielsch Engineering, Inc developed a program called: 4-SYTE System Strategy that is currently utilized in more than 60 power plants within the United States and Canada.
Abstract: Boiler tube failures remain the leading cause of lost availability in power boilers across global markets The need for strategic planning in regard to inspections, preventative maintenance and targeted replacements has never been greater Identifying the root problem(s) is essential and must be properly managed for continued safety, reliability and availabilityThe process associated with integrating a boiler management program can be viewed as an insurmountable obstacle for many utility operators and owners In many cases, the cookie cutter approach that is often used results in insufficient reliability recovery However, using modern technology and tactics to strategically manage and properly identify specific operating and design conditions has proven exceedingly successful in reducing a unit’s forced outage rate [EFOR]Specific challenges plants are faced with include the reduction of onsite engineers, aging workforces and equipment, and the need to remain competitive in a challenging global energy market Plant managers are routinely faced with the complex task of determining the current condition of their equipment, forecasting outage budgets and schedules, and performing risk assessments Additionally, insurance companies are increasingly requiring inspection and maintenance records that are not always up-to-date or readily available The solutions to reducing the EFOR of a unit involves taking a comprehensive approach to boiler management utilizing unit specific operational training, advanced data management, and strategic inspection, maintenance and replacement prioritization Implementing this comprehensive approach has awarded millions in savings for plant managers that have adopted this strategy Implementing a unit specific, target driven, and strategic plan enables utility owners and operators to succeed in today’s competitive market by increasing the unit’s reliability and availability without sacrificing safety or environmental standardsThielsch Engineering, Inc developed a program titled: 4-SYTE System Strategy that is currently utilized in more than 60 power plants within the United States and Canada Unit specific strategic planning is necessary for all facilities that rely on these critical components Advanced technology must be adopted by all energy producers to ensure they remain competitive and profitableCopyright © 2014 by ASME