Method and system for detecting state of power distribution transformer under harmonic load influence

Abstract

The invention discloses a method and system for detecting the state of a power distribution transformer under harmonic load influence. The method includes the following steps that: the noise signals of the power distribution transformer are detected; a noise signal characteristic parameter and a sound pressure level are extracted; and the noise signal characteristic parameter is compared with a preset noise signal characteristic parameter threshold value, if the noise signal characteristic parameter is higher than the preset noise signal characteristic parameter threshold value, it is judged that the power distribution transformer is in a harmonic load operating state, and the sound pressure level is compared with a preset sound pressure level early warning threshold value, if the sound pressure level exceeds the preset sound pressure level early warning threshold value, it is judged that the operation of the power distribution transformer is abnormal, otherwise, it is judged that the operation of the power distribution transformer is normal. The system comprises a noise signal detection program unit, a noise characteristic extraction program unit and a state detection program unit. According to the method and system of the invention, contact with electrified equipment is not required, so that the safety of detection is high; workers are not required to go to a site to carry out detection and analysis; and therefore, the method and system of the invention have the advantages of time-saving and labor-saving performance, high safety, high efficiency and convenient detection.

Description

technical field [0001] The invention relates to electric power safety monitoring technology, in particular to a method and system for detecting the state of a distribution transformer under the influence of a harmonic load. Background technique [0002] Distribution transformer is an important part of power distribution network, and its safe operation is of great significance to provide stable and reliable power supply to power users. The load characteristics of the distribution network are relatively complex. With the popularization of frequency converters in household appliances (such as air conditioners, refrigerators, etc.), the load harmonic content of distribution transformers has generally been at a relatively high level. The increase of load harmonic content leads to the increase of transformer loss, which leads to the increase of transformer temperature, noise and vibration. The long-term operation of the transformer with high harmonic load may easily cause insulat...

AI Technical Summary

Problems solved by technology

At present, current transformers are generally used to measure the harmonic current of distribution transformers. This method requires pre-installing sensors on the transformer busbar, requires on-site work and direct contact with live equipment, and has certain potential safety hazards.

There are a large number of distribution transformers and a wide distribution range. In addition, many distribution transformers are not pre-installed with current transformers before they are put into operation. As a result, operators cannot directly understand the load harmonic conditions and operating conditions of transformers.

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