一种基于D-S证据理论和稳态量的配电网故障选相方法研究

摘要

Taking the fault in neutral isolated system for example, the amplitude and phase relationships among positive-sequence,negative-sequence and zero-sequence fault components of voltage and current are analyzed.On the basis of that, the characteristic quantities, which can identify fault phase, are defined.Afterward, they are used to establish the decision tree of fault phase selection approach.The basic probability assignments (BPAs) of the characteristic quantities are defined.So, the fault phases are selected through fusing the characteristic quantities by D-S evidence theory.Through establishing the simulation model in PSCAD/EMTDC environment, the proposed approach is verified in simulation environment.Moreover, the adaptability of proposed approach to neutral resonant grounded system, different Signal Noise Ratios (SNRs) and arc faults is thoroughly studied.The simulation results show that the proposed scheme possesses high correctness and strong anti-noise ability, and it is not influenced by the change of neutral grounding style and non-linear transition fault resistances induced by arc.%以中性点不接地系统发生故障为例,分析了正、负和零序电压、电流故障分量之间的幅值和相位关系,在此基础上,定义了标识故障相别的特征量,建立了故障选相的决策树.定义了每个特征量的基本可信度指派函数,通过D-S证据理论对各个特征量的值进行融合得到故障选相结果.通过在PSCAD/EMTDC环境下建立仿真模型,对提出的选相方法进行了验证,并且研究了方法在中性点谐振接地系统、不同信噪比以及电弧故障下的适应性.仿真结果表明,该方法选相正确率高,抗噪性能强,不受中性点接地方式变化和电弧故障引起的非线性过渡电阻的影响.