基于风险价值的大规模风电并网电力系统运行风险评估

Operation Risk Assessment for Power System With Large-scale Wind Power Integration Based on Value at Risk

为反映未来时间区间内风电功率波动对电力系统整体运行风险的影响,基于风险价值理论建立了大规模风电并网电力系统切负荷风险变化指标和系统越限风险变化指标,并设计了具有递进关系的三层风险评估指标。首先,基于风电场功率预测输出序列,计算系统切负荷风险指标、线路越限风险指标和电压越限风险指标;其次,综合各时刻的第一层评估结果,采用Logistic分布和指数分布描述各指标的概率分布情况,基于风险价值理论计算出表征未来时间区间内电力系统整体风险水平的第二层评估指标,并引入综合风险指标作为第三层评估指标,全面合理地评估电力系统运行风险。最后,通过IEEE-RTS79算例系统验证了所提模型和方法的合理性,并进一步分析了不同风电接入节点、不同风电接入容量以及风电集中接入和分散接入对系统运行风险的影响。

In order to reflect the impact of wind power fluctuation on the overall operation risk of the power system in the future time periods,this paper establishes the load shedding risk change indicators,the line overload risk change indicators and voltage violation risk change indictors,and designs a three-layer assessment indicators with a progressive relationship in the power system with large-scale wind power integration based on the value at risk theory.Firstly,the assessment indicators in the first layer such as the load shedding risk indicator,the line overload risk indicator and the voltage violation risk indicator are calculated based on the wind power prediction output sequence.Secondly,synthesizing the results of the first layer assessment indicators at all moments and using the logistic distribution and exponential distribution to describe the probability distribution of each indicator,the value at risk theory is introduced to calculate the second layer indicators that reflect the overall risk level of the system in the future time periods,and the comprehensive risk indicators that are used as the third layer indicators are introduced to comprehensively evaluate the power system operation risks.Finally,the rationality of the proposed model and method is verified with the analysis in the IEEE-RTS79 system.This paper further analyzes the impact of different wind farm access nodes or access capacities and wind farm centralized access or decentralized access on the system operation risks.