基于CVaR分析的新能源配电网电压风险评估模型

针对风光等分布式新能源大规模接入给配电网带来反向潮流而造成的电压波动大、局部区域电压偏高的问题,在传统配电网运行风险评估理论的基础上,结合分布式电源、电动汽车和负荷概率模型,采用严重度函数描述了电压偏高、偏低的风险,构建节点电压偏高、偏低的严重性函数。将传统风险评估理论的事故风险评估替换为基于条件风险价值(CVaR)模型,提出了考虑电动汽车和负荷不确定性的事故冲击和损失计算方法,建立了电压波动的CVaR风险指标,提出了分布式电源发电功率、电动汽车充放电功率的特殊函数的估计方法。以IEEE33系统为计算实例,计算了正常运行和预期故障线路2种情况下的电压波动的CVaR风险值,验证了该方法的可行性和适用性。

Risk assessment model for distribution network with renewable energy based on CVaR analysis

Aiming at the problems of large voltage fluctuation and high local voltage caused by reverse power flow due to large-scale access of wind and solar distributed renewable energy sources to distribution network, basing on the traditional risk assessment theory of distribution network operation, the probability model of distributed generation systems, electric vehicle and load are combined, the risk of high and low voltage are described by using severity function, and a severity function is proposed for high and low nodal voltage. The accident risk assessment in traditional risk assessment theory is replaced by contditional value of risk (CVaR) model. A calculation method of accident impact and loss considering the uncertainty of electric vehicle and load is proposed. The CVaR risk index of voltage fluctuation is established. The estimation method of special functions of distributed generation, charging and discharging power of electric vehicle is proposed. Taking IEEE33 system as an example, the CVAR risk values of voltage fluctuation in normal operation and anticipated fault cases are calculated, which verifies the feasibility and applicability of this method.