多DG不确定性建模及其对配电网谐波潮流的影响

分布式电源(DG)出力的随机性和间歇性导致其并网谐波电流具有不确定性,进而导致含DG配电网的谐波分布具有不确定性。为处理配电网谐波潮流计算中DG作为谐波源的不确定信息,以复仿射数代替点值,建立DG并网逆变器输出阻抗复仿射模型,该模型反映了直流侧电压源的不确定性对DG并网谐波电流的影响。在所提模型的基础上,改造传统确定性谐波潮流算法,提出含多DG配电网的不确定谐波潮流计算方法分析DG不确定性对谐波潮流的影响。采用典型33节点配电网算例进行仿真,与确定性分析方法计算结果的对比验证了所提方法的有效性和应用价值。

Uncertainty modeling of multiple DGs and their influence on harmonic power flow in distribution network

The variability and intermittency of DG(Distributed Generation) outputs result in the uncertainty of grid-connected harmonic current, and thus lead to the uncertainty of harmonic distribution in distribution network with DGs. To deal with the uncertainties of DGs as harmonic sources in harmonic power flow calculation, the complex affine is adopted to replace the point value, and a complex affine output-impedance model of grid-connected inverter of DGs is built, which reflects the influence of the uncertainty of DC-bus voltage source on the harmonic current of grid-connected DGs. Based on the proposed model, the traditional deterministic harmonic power flow method is improved, and an uncertain harmonic power flow calculation method for distribution network with multiple DGs is proposed to analyze the influence of the uncertainties of DGs on harmonic current. A typical 33-bus distribution network is used for simulation, and the comparison with the calculative results of deterministic analysis method verifies the effectiveness and practical value of the proposed method.