Partial optical fiber discharge detecting system

Abstract

A partial optical fiber discharge detecting system comprises a light source, an acoustic-optic modulation device, a sensing light path and a demodulating system. Frequency shifting and delaying are carried out on light emitted by the light source through the acoustic-optic modulation device, and only two paths of light with the same optical path can interfere in the sensing light path and a reference light path. When partial discharge signals occur outside, the generated sound waves act on the sensing light path, the phase position of the interference signals changes, and the related information (intensity, position and the like) of outside partial discharge signals can be obtained by demodulating the variable quantity. Compared with traditional electromagnetic sensing and piezoelectric sensing, optical fiber sensing is insulated from electromagnetism essentially, the sensing optical fiber can be arranged in insulating oil of a transformer, the sensitivity for detecting the partial discharge signals is further improved, multiplexing can be formed easily, and the partial discharge signals can be precisely positioned.

Description

technical field [0001] The invention belongs to the field of power system automation, in particular to an optical fiber partial discharge detection system. Background technique [0002] With the development of the national economy, the requirements for the reliable operation of the power system are getting higher and higher. Electrical equipment is the basic component of the power system. Once an accident occurs, it will not only affect adjacent equipment, but also cause heavy economic losses to users. Large-scale electrical equipment mostly uses various organic synthetic insulating materials such as mineral oil, insulating paper or epoxy resin to form a composite structure. A large number of data show that insulation failure is the main cause of electrical equipment failure. [0003] Partial discharge is not only the main cause of insulation failure, but also an important symptom and manifestation of insulation degradation, which is closely related to the degradation and b...

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Problems solved by technology

The test frequency f of the pulse current method is low (generally f<1MHz), and the frequency band is narrow. It is easily affected by external interference and noise when applied to on-site measurement, and its anti-interference ability is poor. Therefore, this method is only suitable for use in laboratories; The frequency method has many practical applications, but its cost is expensive, the positioning accuracy is not high (±0.1m), and the electromagnetic pulse signal strength of the partial discharge received by the antenna is low, sometimes it is impossible to locate the partial discharge source; in the non-electrical measurement method The chemical detection method and the fluorescent optical detection method are rarely used in actual detection due to their poor sensitivity, low precision, and inability to work for a long time; the ultrasonic method is easy to locate, but it is not easy to arrange multiple sensors, the sensitivity is not high, and the positioning accuracy is easily affected. influences

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