High-intensity temperature measuring fiber grating sensor for transformer winding

Abstract

The invention discloses a high-intensity temperature measuring fiber grating sensor of a transformer winding. The sensor comprises a sensing spherical shell cover, a plurality of grating guiding sleeves are evenly connected outside the sensing spherical shell cover, rubber extension blocks are fixedly mounted on two ends of insides of the grating guiding sleeves, gratings are inserted into the grating guide sleeves, the gratings are parabolic in the grating guide sleeves, the gratings penetrate through the rubber extension blocks and are fixedly connected with the outer sides of the gratings,one ends of the gratings are connected with the sensing spherical shell cover, the other ends of the gratings are jointly connected with fibers, the outer sides of the fibers are sleeved with a metalwire mesh sleeve, one ends of the fibers are connected with a demodulator and a DSP chip in sequence, and the gratings are evenly distributed on the sensing spherical shell cover. The sensor can detect the temperature around the transformer, the detection is more standard, errors are smaller, the grating guide sleeves and the rubber extension blocks protect the gratings, the metal wire mesh sleeveprotects the fibers, performance of the gratings and the fibers is stable, and the sensor detects the temperature with high accuracy.

Description

technical field [0001] The invention relates to the technical field of sensors, in particular to a high-strength temperature-measuring fiber grating sensor for transformer windings. Background technique [0002] The power transformer is one of the most important equipment in the power transmission and transformation system, which is directly related to whether the power grid can operate safely, efficiently and economically. The insulation capacity of the transformer determines the life of the transformer, and the winding temperature of the transformer during operation is the main factor affecting the insulation capacity. In addition, the load operation of the transformer beyond the rated value of the nameplate and its dynamic capacity increase and energy-saving control are based on empirical models, which lack reliable support. . [0003] At present, the winding temperature is usually obtained by thermal analog measurement method or indirect calculation method. There are th...

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Problems solved by technology

The insulation capacity of the transformer determines the life of the transformer, and the winding temperature of the transformer during operation is the main factor affecting the insulation capacity. In addition, the load operation of the transformer beyond the rated value of the nameplate and its dynamic capacity increase and energy-saving control are based on empirical models, which lack reliable support.

[0003] At present, the winding temperature is usually obtained by thermal analog measurement method or indirect calculation method. There are three main methods used to measure the internal temperature of transformers: ① Electrical signal sensor measurement method, such as thermocouple, thermal resistance, etc., such sensors are susceptible to Electromagnetic interference, and limited service life, the measurement effect is not ideal

②Infrared temperature measurement method, this method is non-contact measurement, which is convenient for manual operation, but cannot realize online real-time measurement, and is susceptible to background noise and electromagnetic environment interference

③Optical fiber temperature measurement method, among them, the temperature measurement accuracy, spatial positioning accuracy and response time of the distributed optical fiber temperature measurement method based on the principle of Raman scattering or Brillouin scattering are mutually restricted, and currently cannot meet the requirements of the internal transformer. Accurate temperature measurement requirements, and fluorescent optical fiber or semiconductor transmission and reflection optical fiber temperature sensors are point-type temperature measurement, with few measurement points, and their layout inside the transformer often needs to be estimated based on experience, which has certain limitations in practical applications

[0005] (1) The grating and optical fiber of the sensor are relatively fragile. When the force is deformed, the grating or optical fiber is easily broken or damaged due to the pulling force or too much bending, which leads to inaccurate temperature measured by the sensor, and even As a result of signal transmission failure, if the temperature of the transformer winding cannot be accurately detected, the internal temperature of the transformer cannot be adjusted in time, and the performance of the transformer will decline or even burn out.

[0006] (2) The grating of the general fiber grating temperature sensor has fewer contact points with the temperature measured by the transformer. Since the temperature around the transformer is not necessarily the same, a single detection value cannot judge the overall temperature of the transformer winding, but the temperature of the transformer winding must be measured. All surrounding temperatures require a lot of sensors, increasing volume and cost

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