Online measurement method and system for capacity of transformer

Abstract

The invention belongs to the technical field of power systems and particularly relates to an online measurement method for the true capacity of a transformer. The measurement method is disclosed by aiming at the conditions that the nameplate of the transformer can possibly lose in practical operation, the capacity of the nameplate does not coincide with the true capacity and the like. The online measurement method for the true capacity of the transformer has the measurement principle that the relation between the short-circuit impedance and the primary and secondary voltage current of the transformer is deduced through analyzing the equivalent circuit model of the transformer. In order to avoid performing online measurement on the high-voltage side signal of the transformer, an ideal alternating current power supply signal is utilized by the online measurement method for the true capacity of the transformer to replace the high-voltage side voltage of the transformer according to the characteristic that the high-voltage side voltage hardly changes along with load when the transformer normally runs; then, acquired secondary voltage and current signals and ideal power supply signals are simply calculated, and obtained signals are further calculated in the manner of linear fit, thus, the short-circuit impedance of the transformer to be measured can be obtained, and finally, the true capacity of the transformer is calculated by utilizing a short-circuit impedance method. By adopting the measurement method, the disadvantage of measuring the capacity of the transformer when a power supply is interrupted is overcome, and the safety of the online measurement technology is greatly improved.

Description

technical field [0001] The invention relates to the technical field of power systems, in particular to an on-line measurement method for transformer capacity, and also relates to an on-line measurement system for transformer capacity. Background technique [0002] The rated capacity of the transformer represents the size of the electric energy transmitted by the transformer. The selection of transformer capacity is comprehensively considered by the power supply department according to the transformer position, load and normal overload capacity, accident overload capacity and the requirements of the economical operation of the transformer. However, there are two phenomena in the market at present: 1) some power consumers change the transformer name brand capacity, and change the large capacity to small capacity in order to pay less basic electricity bills; 2) a small number of transformer manufacturers use small capacity and high loss to The transformer pretends to be a larg...

AI Technical Summary

Problems solved by technology

At present, the test methods for transformer capacity mainly include loss comparison method, impedance voltage method and three-element method, but these methods are all measured offline.

When there are doubts about the capacity of distribution transformers running in the network and it is necessary to test them, there are great disadvantages in measuring the capacity of transformers by using the power-off method. , uninterrupted power supply requirements

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