A Novel Flux-Based Protection Scheme for Power Transformers

A Novel Flux-Based Protection Scheme for Power Transformers

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Part of #A Novel Flux-Based Protection Scheme for Power Transformers# :

Publishing year : 2014

Conference : The 9th Specialized Conference on Protection and Control of Power Systems

Number of pages : 6

Abstract: Power transformers must be protected against faults and should be monitored permanently to increase power system reliability and reduce maintenance costs. Internal Turn-Turn faults (TTFs) are the most common faults in power transformers, which can seriously reduce the useful life of these equipment. Although common protections such as differential relays can detect some of the internal faults, some other ones (such as TTFs and short circuit near the neutral point) can not be detected by them. Also, these relays may trip erroneously due to energizing inrush currents, transformer over excitation, and occurring CT saturation at one side. In this paper, a novel Linkage Flux Based (LFB) scheme is proposed to detect TTF in power transforms, which uses some Search Coils (SC) located on the transformer legs to sense the associated linkage flux. Any difference in induced voltage in the corresponding SCs (located in any leg) suggests the passing of unsymmetrical linkage fluxes through them (against normal conditions), which stands for occurrence a fault inside the transformer. The proposed technique can not be used to protect power transformers, but can also be used to find fault location during repair operations, as well