一种基于电流比变化量的变压器匝间短路保护方法

A protection method of transformer inter-turn short circuit based on the variation of current ratio

变压器匝间短路特别是少匝数短路时,现有保护很难检测并发现故障。基于变压器绕组两侧电流比值与两侧绕组匝数比值之间的对应关系,提出了一种电流比变化量匝间保护方法,构建了保护动作判据。该方法不仅能躲过变压器内部相间故障及变压器外部短路的影响,还能区分匝间短路故障相,具有很高的保护灵敏度。通过对试验变压器进行的内部匝间短路试验,验证了所提方法的有效性。

It is difficult to detect and find fault for traditional protection when transformer short circuit fault occurs at inter-turn, especially when the turns are small. This paper proposes a new method using variation of current ratio of two winding sides of transformer, based on the corresponding relations between the current ratio. The protective action criterion is constructed. The new method not only avoids the influence of the internal phase fault and the external short-circuit, but also distinguishes the inter-turn short circuit from other faults with a high sensitivity. The validity of this method has been proved by tests on a simulation transformer.