Reliability Assessment Of Generation System Based On Wind Adjustment And Reactive Power Balance

This article comes from Science and Technology Project by Shanxi“Research on active power adjustment of wind farm and technical retrofitscheme of low voltage across”.Nowadays, with the global energy crisis and environmental problemsbecoming increasingly severe, wind power is developing rapidly. Due to therandomness and uncertainty of wind power, grid-connected wind power willhave an effect on the level of system reliability. However the results of presentreliability assessment of generation system containing wind power are often notcomprehensive enough. The reasons are that active power and reactive powerare two important aspects of power system, while in the present reliabilityassessment, only active power adequacy is focused on and reactive power issuesare ignored. On the actual operation, wind power capacity accepted to thesystem should be within certain limits, because it is restricted by certain factors.In this paper, reliability level of generation system with wind power isestimatedfrom two aspects of active power and reactive power respectively. Based onwind power adjustment the maximum admissible wind power capacity is calculated, and its contribution to system reliability is analyzed.In view of the existing wind power reliability assessment without the effectof reactive power, this paper proposes a new wind power reliability assessmentmodel. Considering wind turbine failure, on the basic of wind speed probabilitydistribution model and output model of wind turbines, the wind farm integratedreliability model is established within the influence of reactive powercompensation equipment failures in wind farm.This paper studies reliability assessment of power generation system withwind power from the perspective of active and reactive power, respectively.State enumeration method is applied to filter system state. Based on the methodof cut-off fault order, the fourth and below fault order conditions of generationsystem (including active and reactive power sources) are analyzed. A three-stageload shedding technique is implemented to solve reliability problems induced byinsufficient active power, insufficient reactive power and voltage violation.Because the node voltage violation is mostly caused by lack of local reactivepower, increasing the local reactive power compensation can be an effectivesolution to the problem of node voltage violation. In this article, the increasedreactive power compensation strategy is used to solve nodal voltage limitproblem Reliability index of the third stage load shedding can provide systemoperators and planners very important information for reactive powercompensation location.On one hand, in actual operation of power system, wind power capacity increased by certain factors cannot be unlimited. On the other hand, theprobability according to rated output of wind farm is very small. In this article,taking to meet power balance and peak-shaving demand as the prerequisite,based on wind power adjustment wind power accepted capacity is calculated.Taking an actual system as an example, the reliability of the system isassessed from both active and reactive power, respectively. The results verifiedthat the proposed wind farm integrated reliability model and reliabilityassessment method are effective. Based on wind power adjustment wind poweraccepted capacity is calculated. In addition, accessed to the wind power capacitythe system reliability level is estimated. Results show that when consideringwind power adjustment wind power accepted capacity is increased, so that thecontribution of wind power to system reliability level is improved.