At present, most of the winding fault detections transformers use offline methods, which require entire line to be powered off or after transformer has been shut down due a serious fault, and they cannot detect running status windings in real time online. Since will impacted by VFTO during operation, is used as excitation, basic principle frequency response method propose an online detection de...

Freestanding single-crystal complete nanorings of zinc oxide were formed via a spontaneous self-coiling process during the growth of polar nanobelts. The nanoring appeared to be initiated by circular folding of a nanobelt, caused by long-range electrostatic interaction. Coaxial and uniradial loop-by-loop winding of the nanobelt formed a complete ring. Short-range chemical bonding among the loop...

Target space duality is reconsidered from the viewpoint of quantization in a space with nontrivial topology. An algebra of operators for the toroidal bosonic string is defined and its representations are constructed. It is shown that there exist an infinite number of inequivalent quantizations, which are parametrized by two parameters 0 ≤ s, t < 1. The spectrum exhibits the duality only when s ...

This paper presents a new approach to identify distributed parameters of a lumped-element model for a power transformer. A simplified circuit of a lumped-element model is developed to calculate frequency responses of transformer windings in a wide range of frequency domain. In order to seek optimal parameters of the simplified circuit of the transformer, an intelligent learning technique, based...

The inter-turn short-circuit fault of a power transformer has large current in the winding, which will cause serious heating and deformation winding may threaten safety transformer. Under this background, paper proposes scheme based on open-delta voltage monitoring identification short circuits transformers. First, mathematical modeling analysis principle transformers are carried out, expressio...

Power system overvoltages due to switching, lightning and other disturbances are the main problem for designers of the power transformers. Once some frequencies of the incoming surges match with some of the natural frequencies of transformer winding, the resonance phenomenon is expected in transformer winding. The resonant overvoltages may destroy the insulation between turns and cause to insul...

The classification of polygons is considered in which two polygons are regularly equivalent if one can be continuously transformed into the other such that for each intermediate polygon, no two adjacent edges overlap. A discrete analogue of the classic Whitney-Graustein theorem is proven by showing that the winding number of polygons is a complete invariant for this classification. Moreover, th...

Power transformer, as a crucial equipment for power transmission, frequently suffers winding deformation defects, owing to the impact of huge external short-circuit current in actual operation. To resist rapid deterioration online monitoring states is imperative, depending on thorough understanding defects. Unfortunately, there are not much related research form and location, two key objects di...