在中性点不接地的配网系统中,由于电磁式电压互感器(PT)饱和而引起的铁磁谐振是出现最频繁,造成事故最多的一种内部过电压。目前,系统采用的消除谐振的主要措施有以下3种:(1)在 PT 开口三角绕组两端并接低值电阻;(2)在 PT 一次侧绕组中性点串接高值电阻;(3)在 PT 一次侧绕组中性点串接零 In neutral network ungrounded distribution system, due to the electromagnetic voltage transformer (PT) saturation caused by the ferromagnetic resonance is the most frequent occurrence, causing an accident most of an internal over-voltage. At present, the system adopts the following three main measures to eliminate resonance: (1) Connect low-value resistances to both ends of the delta winding of the PT opening; (2) Connect the high-value resistance in series with the neutral point of the primary winding of the PT; ) In the PT primary winding neutral point series zero