Showing papers on "Forced outage published in 2010"

Reliability assessment of a wind-power system with integrated energy storage

Abstract: This study looks into reliability assessment and components rating of a wind-power system with integrated battery energy storage. The system can potentially be used in remote electrification projects to mitigate the reliance on diesel generators. A reliability assessment method has been proposed in this study, based on a combination of the traditional analytical and simulation-based approaches, to enable calculation of reliability indices, required battery capacity and power rating, and power rating of the power-electronic converter of the wind-power units. The proposed method is easy to implement in the MATLAB software environment, takes into account the units forced outage rate (FOR), and also permits modelling of the grid-connected mode.

Determination of Optimal Spinning Reserve of Power Grid Containing Wind

Abstract: Along with increasing wind farms' scales,traditional methods to decide spinning reserve are no more appropriate.The authors research how to take the presupposition that both security and economy of power grid operation and the uncertainty factors such as forced outage of generation units,predicted-deviation of load and wind turbine output into account to decide optimal spinning reserve,which power grid containing wind farm requires.Utilizing cost effectiveness analysis method in economics,taking minimized generation cost of power grid and expected outage cost as objective,the predicted-deviations of load and wind power output are analyzed by probability density function and the analysis results are led into the calculation of outage capacity of generation units;the demand of optimal spinning reserve is solved by intelligent optimization algorithm,meanwhile the sensitivity analysis of the influences of related factors on optimization result is performed.Simulation results show that the proposed model and algorithm are feasible.

Loss of load probability of a power system : Kerala

Abstract: By virtue of the vital nature of electric power, both to our economic and personal well being, a power system is expected to supply electrical energy as economically as possible, and with a high degree of quality and reliability. The developed countries in general place higher reliability standards on the performance of electricity supply. However, there has been no significant study in the context of the Indian power sector to analyze reliability in terms of loss of load probability; the technical appraisal of the State power systems in general is confined to examining the plant load factor (PLF) as a measure of capacity utilization only. The present study is a modest attempt to evaluate the reliability of the Kerala power system in India in the framework of a theory-informed methodology: following a detailed discussion of the methodology used in this study, the maximum likelihood estimates of availability and forced outage rates as well as loss of load probability measures are calculated for the 10 hydropower plants of Kerala. JEL Classification: C2; Q4.

Probabilistic reliability evaluation of composite power systems including wind turbine generators

Abstract: This paper proposes a new methodology for evaluating the probabilistic reliability of a grid constrained composite power system including wind turbine generators(WTG). The proposed model can consider capacity limitations and transmission line forced outage rates. The importance of renewable energy sources has been growing at a high rate as a result of being environment friendly. In particular, wind energy is one of the most successfully utilized such source to produce electrical energy. The random nature of wind speed can be incorporated in the evaluation by representing the WTG by multi state models. A simple case study shows in detail how it is used to perform a reliability evaluation study in proposed model.

A Calculation Model for Price Duration Curve

Abstract: In view of the load level,the price duration curve(PDC) is defined.On this basis,the definition of the average PDC under all loads in the study period is given.In accordance with the definition,a calculation method of PDC is proposed by taking account of unit forced outage and unit stochastic bidding.By substituting the equivalent units for the capacity block of generating units,this method makes it possible to obtain the probability of marginal price and PDC based on the power system probabilistic production simulation.This method is characterized by conceptual clarity,flexibility and time saving.Finally,an illustrative case study of PJM electricity market is presented.

Web based online realtime information system for reliability of composite power system including wind turbine generators

Abstract: This paper proposes a new methodology for evaluating the probabilistic reliability of a grid constrained composite power system including wind turbine generators(WTG). The proposed model can consider capacity limitations and transmission line forced outage rates. The importance of renewable energy sources has been growing at a high rate as a result of being environment friendly. In particular, wind energy is one of the most successfully utilized such source to produce electrical energy. The random nature of wind speed can be incorporated in the evaluation by representing the WTG by multi state models. Furthermore, web based online real-time reliability integrated information system (WORRIS) was developed with the proposed methodology in this paper. This paper describes architecture of the WORRIS Version 1.0 system developed preliminarily in this study. It is originally a reliability information system based one day go ahead system.

A study of the parameters influencing the Capacity Credit of WECS- a simplified approach

Abstract: In recent years, penetration of wind generated electricity into power grids has been increasing significantly. During the last few decades, wind energy has doubled in capacity every three years. Because of the intermittent characteristics of wind power, it is usually difficult to determine an acceptable penetration level to maintain specific reliability requirements. The need for better capacity credit assessment for wind electric conversion systems is clear. Considerable work has been done in the past to estimate the capacity credit of WECS (wind electric conversion system) and several approaches have been proposed. This paper examines the influence of different parameters on the Capacity Credit using a simplified approach based on an effective forced outage rate (FOR) for WECS. The parameters considered are penetration level, amount and variability of load, generation configuration and wind regimes.

Analysis on Reliability of HVDC Power Transmission Systems of State Grid Corporation of China in 2009

Abstract: The reliability indices completion for HVDC power transmission systems of State Grid Corporation of China (SGCC) in 2009 are summarized.The reasons that impact the indices of scheduled energy unavailability and forced energy unavailability as well as monopole and bipole forced outage times are analyzed in details.Based on the scheduled and forced outages condition for HVDC power transmission systems of SGCC in 2009,the suggestions on reducing the scheduled energy unavailability and the forced energy unavailability of HVDC power transmission systems are given respectively.Analysis results given in this paper are available for reference in the decision-making of enhancing production management level of HVDC power transmission systems and improving their operational reliability.

Grid constrained probabilistic reliability evaluation of power systems including wind turbine generator

Abstract: This paper proposes a new methodology for evaluating the probabilistic reliability of grid constrained composite power system including the WTG. The proposed model can consider capacity limitation and forced outage rate of transmission line. The importance of renewable energy sources has been growing at a high rate as a result of being environment friendly. In particular, wind energy is one of the most successfully utilized of such sources to produce electrical energy. Because of the randomness of wind speed, however, the multi-state model is suited for modeling wind turbine generators(WTG). A simple case study using two buses system shows in detail how it is used to perform a reliability evaluation study in proposed model.

Equivalent reactance model for multi-module TCSC in power system probabilistic analysis

Abstract: The thyristor controlled series compensator (TCSC) is possible to improve transmission capability and power system reliability. In the existing transmission capacity model, the state availability and total reactance are decided by the line flow. The line flow is however dependent on the network configuration, and unknown before the probabilistic sampling in reliability analysis. In this paper, the equivalent reactance of the state space of the series-compensated line is defined, which is decided by the control object in short-term analysis, and discrete after the forced outage instead of continuous over the controllable range. The proposed model is applied to power system probabilistic load flow analysis. By comparing the mean, variance and distribution of the line flow, it is found that with desirable compensation degree and TCSC's availability, the series compensated line may have similar power transmission capability as parallel lines.

Multivariate statistical modeling on the 3-state (up, derated, down) availability of repairable hardware units and networks with the Sahinoglu-Libby probability distribution using Monte Carlo simulation

Abstract: The principal author in response to then-in-2007-unsolved homework question from his Wiley textbook proposes to generate the multivariate probability distribution model of an important pillar of the trustworthiness employing simulation techniques by proper modeling of the problem. Namely, the availability of a component (unit) is studied when the units have three states with a derated state included beyond the usual 2-state assumption. It is usually assumed that repairable units reside in either up (operating) or down (non-operating) states where FOR (Forced Outage Rate) = down time/(up time + down time). On the contrary, many real-life grid units from routers or servers in cybersystems to the electric-power generating plants, and the water-supply networks or dams, as well as Markov state diagrams do not operate in a dichotomously full or empty capacity. Due to lack of a closed-form solution of the 3-State SL model as opposed to a closed-form of the 2-State model, the analysis can only be conducted by Monte Carlo simulations using the empirical Bayesian principles to estimate the full and derated availability of a repairable hardware unit. Industrial applications for units and networks will be numerically illustrated.

Analysis of potential dangers leading to HVDC outage in valve cooling system

Abstract: Taking the valve cooling system of Nanqiao converter station as an example,its problems and the transformation process are presented.Then,the valve cooling system protection theory and its settings are introduced.The HVDC outage accidents caused by valve-cooling system in recent years are listed and analyzed.The defect distribution of inner and outer valve cooling system in the six domestic HVDC transmission projects is illustrated.The hidden danger of single or dual poles blocking includes single sensors, power lost,water leakage,wrong settings,etc.Their corresponding countermeasures are also presented.After taking the necessary corrective and remedial measures,the HVDC forced outage rate is greatly reduced.

Taming Condenser Tube Leaks, Part II

Abstract: Summer peaks are still with us, and every unit on your system must be prepared to operate at a moment's notice. Spot power prices are so high that you expect phone calls asking for a few more megawatts from your units. Then your plant chemistry lab calls to report a condenser tube leak. Your options are few: Shut down immediately and get charged with a forced outage, ignore the leak and keeping running until fall, or schedule a maintenance outage next weekend and hope the leak can be found and fixed. In Part I, we examine what you need to know in order to make an informed decision. In Part II, we'll explore the actual damage mechanisms.

Wind farm reliability model based on analytical method

Abstract: Based on the concept of frequency and duration,the probability,frequency,transfer rate of each wind farm state are calculated with the wind speed data and wind turbine parameters.On the basis of Markov chain method,a wind farm reliability model based on analytical method is proposed with the stochastic characteristics of wind farm power output and the forced outage rate of wing turbine fully considered.The aggregation concept is applied to model the wind farm as a conventional unit with multiple states,which greatly decreases the power output states.Simulation is carried out for the RBTS(Roy Billinton Test System) added with ten V80-2 MW wind turbines and the indexes of LOLE(Loss Of Load Expectation),LOLF(Loss Of Load Frequency) and LOLD(Loss Of Load Duration) are used to evaluate the effect of wind farm on power system reliability.The comparative analysis shows the proposed model is feasible and effective.

Generators maintenance scheduling of generation companies in Korea considering uncertainties

Abstract: A technique using a fuzzy search method which is based on fuzzy multi-criteria function has been proposed for GMS(generator maintenance scheduling) in order to consider uncertainties of forced outage rate of generators and multi-objective function. This paper evaluates the results of maintenance scheduling of the seven generation company obtained by the previous proposed method. Especially this paper focus on the GMS of Korea Western Power Co. The probabilistic reliability evaluation method was used to calculate production cost and used as criterion.

Design method for high availability of turbonator and evaluation method thereof

Abstract: The invention relates to a design method for high reliability of a turbonator and an evaluation method thereof, and the invention is characterized by comprising the following concrete steps: (1) determining a design colligation coefficient Ak; (2) determining the operation reliability AO1 of the turbonator body; (3) determining the operation reliability AO2 of a turbonator excitation system; (4) determining the operation reliability AO3 of a turbonator oil system; (5) determining the operation reliability AO4 of a turbonator cooling system; (6) determining the operation reliability AO5 of a turbonator monitoring and protecting system; (7) determining a correction factor ki of a planned correction type of the turbonator; (8) calculating forced outage rate (FOR) of the turbonator; (9) evaluating the result; and (10) improving the design. The invention has the advantages of realizing reliable designing and improvement of the turbonator, and achieving the technical effect of lowering the FOR to improve the reliability.

An Improving Fast Sorting Technique for Generating System Reliability Evaluation

Abstract: Based on the fast sorting technique,an improving fast sorting technique for generating system reliability evaluation is proposed.In the sorting of units,the forced outage rate of units and its influence on system reliability are comprehensively considered to accelerate the convergence.Alternative neighboring states and minimum neighboring states set are proposed to reduce the states to be selected,thus the memory footprint is decreased and the computing speed is speeded up.The proposed algorithm is put into operation in the on-line reliability evaluation system of East China power grid.

Research on Reserve Requirement of Interconnected System Based on Loss of Load Probability

Abstract: Reserve requirement model of interconnected system based on the traditional power system outage model is developed,considering the system load level,tie-line capacity,tie-line forced outage rate,etcTwo-dimensional array method is used to calculate the loss of load probability(LOLP)IEEE 30 node simulation example demonstrates the feasibility of using reserve requirement model to determine reserve capacity of interconnected system

Operational reliability evaluation of generating system considering ageing failure

Abstract: The electric generating unit's operational state of both history and scheme should be taken into consideration in the operational reliability evaluation of generating system. The generating unit's ageing failure is taken into account in the paper. The repairable failure unavailability and the ageing failure unavailability are deduced from the unified definition of unavailability, and the forced outage model is obtained by using the theory of multiple failure competing risk failure. The selections of formula for computing unavailability in the reliability evaluation of different cycles are discussed. And they are applied to operational reliability evaluation of generating system, which is based on daily generation scheduling. Simulation analyses are given to indicate the effectiveness of the method. The methods and conclusions can be used in operational reliability evaluation of composite generation and transmission system, and also can be applied into operational reliability evaluation of generating system including wind energy and solar energy.

Analysis of impact of generating capacity constraints in Mexico's Sistema Interconectado Nacional using equivalent assisting unit approach

Abstract: This paper presents the results of a reliability analysis of the generation adequacy of the Mexico's Sistema Interconectado Nacional (SIN), which is comprised of seven interconnected control areas (systems). Analysis was performed taking into account scheduled and forced unit outages, additions of new units, permanent shut down of obsolete units, load demand, additions of new tie lines, and forced outage rates of existing tie lines between areas. 2010 analysis includes the impact of interconnection between Mexico and Guatemala's Power System. Risk indexes -Loss of Load Expectation (LOLE) and the Loss of Energy Expectation (LOEE)- were computed using an analytical (recursive) method and applying the equivalent assisting unit approach. Results of a previous reliability analysis considering SIN as one single area [1] are compared with results considering interconnections between areas.

Modeling environmental policies in probabilistic generation system planning reserve margin assessment

Abstract: This paper provides an overview of the California Independent System Operator (CAISO)’s efforts to incorporate environmental policies regarding electric power industry into its probabilistic planning reserve margin studies. Currently, load serving entities such as Investor Own Utilities (IOUs) in the State of California, with its retail load under the jurisdiction of the California Public Utility Commission (CPUC), are required to procure reserve level at 15–17%. This requirement is deterministic in nature and does not include the potential impact of additional reserve requirement due to environmental policies. The CAISO, which controls 80% of the state’s electrical load, is investigating the use of probabilistic planning for planning reserve margin (PRM) of the load serving entities under its operational control. The paper provides an overview of CAISO study results for PRM under various load and resource scenarios, increase in generators’ forced outage rate, and impacts due to California’s environmental policies regarding electric supply sector, such as its once-through cooling (OTC) draft policy and Renewable Portfolio Standards (RPS) targets.