On-line monitoring device and monitoring method for insulation of wire rod hydroelectric joint of internal water-cooled generator

Abstract

The invention relates to an on-line monitoring device and monitoring method for insulation of a wire rod hydroelectric joint of an internal water-cooled generator. According to the technical scheme, a weld joint is arranged between a water box and a water box cover of the hydroelectric joint of the wire rod of the generator, and a gas detection box which is arranged along the weld joint and covers the weld joint is arranged on the outer side of the weld joint; the bottom surface of the gas detection box is in sealed connection with the outer surface of the generator wire rod hydroelectric joint so that an inner cavity of the gas detection box forms a relatively closed tracer gas monitoring space, and the whole section of the weld joint is located in the coverage range of the tracer gas monitoring space; the gas detection box is connected with a three-way valve for charging the tracer gas or for monitoring the internal pressure of the tracer gas monitoring space. According to the present invention, the change of the pressure values on the two sides of the hydroelectric joint is measured, and the content of the characteristic gas of the inner cooling water tank is measured so as to intuitively determine the insulation performance of each hydroelectric joint so that the safety and the reliability are realized; the gas detection box covering the weld joint provides a second defense line for insulation degradation, and internal cooling water is effectively prevented from entering the generator.

Description

technical field [0001] The invention relates to insulation monitoring of hydroelectric joints, in particular to an on-line monitoring device and monitoring method for insulation of hydroelectric joints of water inner cooling generator wire rods for smart power plants. Background technique [0002] At present, with the national energy industry's carbon peak and carbon neutral goals, the installed capacity of traditional thermal power plants is on a downward trend, and the single-unit capacity of thermal power plants (including nuclear power plants, the same below) in service is basically above 600MW , the reliability of equipment operation has become increasingly prominent. Thermal power plants should be future-oriented so that various existing power generation methods can better adapt to the future smart society and energy revolution and innovation. [0003] The internal water cooling method is mainly used in the wire rods of thermal power plants above 600MW, that is, the c...

AI Technical Summary

Problems solved by technology

[0004] During operation, the hydrogen concentration inside the generator is constantly decreasing due to pipeline leakage or hydrogen cooler leakage. Therefore, hydrogen needs to be continuously replenished during operation. Oxymica Tape

At present, the insulation performance of the water and electricity joints of wire rods mainly depends on the method of applying DC voltage on the surface of the handbag insulation (the name after wrapping the epoxy mica tape outside the water and electricity joints) after the end cover is removed after shutdown. The applied voltage is about 20kV, and the leakage current is passed. The size of the insulation is used to judge the quality of the insulation. The principle of this method is Ohm's theorem, that is, when a fixed voltage U is applied, the insulation resistance R will be poor if the leakage current I is large. Applied DC voltage measurement method and evaluation guidelines", this standard only uses the offline detection method to measure the insulation performance of the water and electricity joints one by one, it cannot effectively realize the online monitoring, and the timeliness of finding problems is also poor, and there are blind spots. The area of ​​the wrapped conductive cloth or metal aluminum foil will affect the test results

And it does not meet the requirements of smart power plants for insulation on-line monitoring data

[0005] The existing invention patent 202010946377.1 "A Method for Judging Hydrogen Leakage of Generator Bars" is only aimed at units with excessive hydrogen leakage in the internal cooling water tank, through the relationship between hydrogen saturation solubility and hydrogen pressure, to assist analysis and judgment of generator hydrogen leakage faults, only It is an idealized analysis from a theoretical aspect, and the specific location of hydrogen leakage cannot be judged, and the insulation status of water and electricity joints cannot be monitored online

It also does not meet the requirements of smart power plants for insulation on-line monitoring data

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