| With the increasing problems of energy and environment, renewable energy hasbeen paid more and more attention such as wind. However, because of the stochasticand intermittent characteristics of wind, the large-scale wind power integration brings aseries of negative impact on reliable operation of power system, which restricts thedevelopment of wind power. Energy storage technology can effectively solve theinstable problem of wind power output. However, the use of energy storage system putsforward new requirements to reliability evaluation of power system. To establish thereliability model of energy storage system and evaluate reliability of thewind-diesel-storage hybrid system has become one of the important research topics.Energy storage system is highly dependent on operating strategies. Based on it, thisthesis introduces three kinds of operating strategies of energy storage system. Strategy1is introduced based on that energy storage system can effectively smooth output powerof wind turbine generator. Strategy2is introduced based on the limit of wind powerpenetration. Strategy3is introduced based on reducing the load curtailment.Considering three kinds of operating strategies and operating characteristics, acharging-discharging model of energy storage system is established by calculatingpower output and stored energy for each state. Considering outage probability of energystorage system, an outage model of energy storage system is established. Thencombining the charging-discharge model with the outage model, a multi-state reliabilitymodel of energy storage system is established. The results of case studies show thatoperating strategies and operating characteristics have a significant impact on thecharging-discharging process of energy storage system. Therefore, considering thesefactors in reliability evaluation is necessary.Base on reliability indices of generation capacity adequacy and reliability indicesof energy storage system such as Expected Discharge Energy, ExpectedCharge-Discharge Times, a reliability evaluation model of the wind-diesel-storagehybrid system is introduced. Combining the multi-state reliability model of energystorage system with the reliability model of wind turbine generator and diesel, therandom sampling and sequential simulation are conducted by Sequential Monte CarloSimulation. Then the output power time series of wind turbine generator, diesel andenergy storage system, and the stored energy time series of energy storage system are calculated. Reliability indices of the system are obtained by observing the simulationprocess. The algorithm is applied to a wind-diesel-storage system. The results of casestudies show that operating strategies and operating characteristics of energy storagesystem have significant impact on system reliability. The impacts of wind speed, windpower penetration, load and rated power of diesel on system reliability are alsoanalyzed.Based on the results of reliability evaluation, cost-benefit analysis ofwind-diesel-storage hybrid system is proposed considering three operating strategies ofenergy storage system, which provides useful information to the dispatching operationof practical power system. Based on improving the system reliability performance andconsidering the capacity cost, energy cost and service life of energy storage system, areliability cost-benefit model of energy storage system is established. The impacts ofcapacity and maximum charging and discharging power of energy storage system on thetotal costs are analyzed. The optimal type of energy storage system is solved by thegenetic algorithm. |
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