System and method of three-phase distribution transformer temperature-rise test based on alternating current low frequency heating

Abstract

The present invention discloses a system and method of a three-phase distribution transformer temperature-rise test based on alternating current low frequency heating. The method comprises: a three-phase four-wire low-voltage input power supply, a three-phase adjustable low-frequency variable-frequency power source and a tested transformer are connected in series in order, an output signal collection module and a temperature measurement sensor module are connected with tested transformer, a main control unit is connected with the three-phase adjustable low-frequency variable-frequency power source, the output signal collection module and the temperature measurement sensor module; and the main control unit emits a voltage regulation and frequency regulation instruction for the three-phase adjustable low-frequency variable-frequency power source according to the feedback signals of the output signal collection module and the temperature measurement sensor. Because the output frequency is low, the test power supply capacity required by the temperature-rise test can be greatly reduced without a high-capacity voltage regulation device or a reactive compensation device.

Description

technical field [0001] The invention relates to the technical field of distribution transformer temperature rise test, in particular to a short-circuit temperature rise test method based on AC low-frequency short-circuit test for transformers and iron core excitation saturation control. Background technique [0002] The purpose of the transformer temperature rise test is to verify whether the heat generated by the total loss of the main body (winding resistance loss and iron core excitation loss) of the transformer under rated working conditions and the temperature at which the cooling device reaches thermal equilibrium meet the requirements of relevant standards and technical agreements, and verify that the product The rationality of the structure and the degree of local overheating of the structure. It is not only related to the safety, reliability and service life of the transformer, but also related to the manufacturing cost of the transformer. [0003] In the tradition...

AI Technical Summary

Problems solved by technology

First of all, the heating power supply must use three AC power sources with an angle of 120 degrees to each other to induce a short-circuit current in the winding on the short-circuit side. Secondly, it must be considered that when the frequency is low, the magnetic circuit of the transformer core will be saturated, resulting in local overheating and damage to the core. The paint film between the silicon steel sheets forms a short circuit between the sheets, which leads to eddy current generation and causes transformer failure

Images