Development of microcomputer protection device for large transformer;

It can be found that DGA is a valid method to detect latent defects in power transformers;PD test is efficient in inspecting insulation faults of large transformers,while ultrasonic PD location for large transformers is still in its tentative .

In this dissertation, a research is made not only on the 3D steady and transient eddy current fields in large transformers,but also on stray losses, the local overheating as well as the mechanical strength of structures after the occurrence of sudden short circuit, using electromagnetic theory and modern numerical methods.

The on-line condition monitoring and fault diagnosis technology for large-sized transformers at home and abroad is summarized in this paper.

Aimed at the question to be taken into consideration for large-sized transformer spiral winding groups different spiral rise angles, calculation was made for transformer leakage magnetic field, spiral angle θ of four models selected were respectively 4.

Brief analysis to the abnormal test result of the damping large-scale transformer;

Several DC resistance measurements for low voltage side winding of large-scale transformer are introduced,detailed in testing process and measuring results.

Through the analysis of drying practice on site for a high capacity transformer,an effective drying method is presented.

This paper introduces a partial discharge (PD) on-line monitoring system for large power transformers.

With the development of electrical industry, more and more large power transformers will be widely used in power system.

Inrush current identification methods currently being used, such as the second harmonic current restraint principle and dead angle method, can\'t very well meet the requirements of modern large power transformer protection.