电力系统运行经验表明,中性点不接地的电力系统中经常发生铁磁谐振现象,铁磁谐振严重影响系统的安全性、稳定和可靠性.为了有效分析电力系统中时有发生的铁磁谐振现象,将配电网系统经过相模变换将其转化0模网络,建立0模网络的数学模型.引入时变相量的概念,建立系统的时变相量数学模型,分析了系统的三个平衡点.定义了系统的稳定裕度和扰动量的计算公式,创新性地把等面积法则应用到铁磁谐振电路的分析中,并讨论了铁磁谐振的发生与故障时间有密切的关系.把对铁磁谐振的分析由以往的定性分析上升到定量分析,并通过ATP仿真验证了等面积法则在铁磁谐振中的实效性.%The operating experience of power system shows that the ferroresonance often takes place in the neutral ungrounded system, which severely impacts the security, stability and reliability of the system. For the sake of efficiently analyzing the increasing ferroresonance phenomena in the distribution network, the paper uses phase-mode transformation to transform the distribution network to a zero-mode network, and establishes a mathematical model of the zero-mode network. After introducing the concept of time-dependent vector, the paper establishes the time-dependent vector mathematical model, based on which, three balance points of the system are discussed. Equal area law is established to be applied to the analysis of the ferroresonance circuit in a novel manner accompanying the definition of stability margin and the calculation formula of disturbing quantity, at the same time the close relationship between the happening of ferroresonance and fault time is investigated. The analysis method of ferroresonance is upgraded from the qualitative view to quantitative view. At last, the effectiveness of the equal area law is verified with the ATP simulation.
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