阅读说明：本技术 基于励磁刀闸过热或大功率刀闸过热的改进方法 (Improvement method based on excitation knife switch overheating or high-power knife switch overheating ) 是由 陈黎明 杨立勇 朱光智 李广山 葛英来 于 2021-06-11 设计创作，主要内容包括：本发明涉及一种基于励磁刀闸过热或大功率刀闸过热的改进方法。传统的检修是用塞尺进行检测,其缺点是,刀闸接触面积小,最小塞尺也是无法精确测量。本发明该方法包括如下步骤：首先是采用强光手电透光的方法判断刀闸接触面的大小,刀闸接触面达不到80%,将刀闸片拆卸下来用小型锉刀,或者刮刀进行如研磨瓦一样进行研磨,研磨完一次用红记号笔进行涂抹研磨面,再安装刀闸,反复分合闸,合闸后再用强光手电透光法检查,对拆下来刀闸片观察分合闸摩擦后的接触面,发亮点为高点,需要再次涂抹红记号笔分进行合闸操作,没有接触的刀闸接触面红记号处,不用研磨,对高点进行在次研磨或刮研。本发明用于基于励磁刀闸过热或大功率刀闸过热的改进方法。(The invention relates to an improved method based on excitation knife switch overheating or high-power knife switch overheating. The traditional maintenance is to detect by a feeler, and the defect is that the contact area of a disconnecting link is small, and the minimum feeler cannot be accurately measured. The method comprises the following steps: firstly, judging the size of a contact surface of a disconnecting link by adopting a highlight flashlight light transmission method, wherein the contact surface of the disconnecting link is less than 80%, disassembling a disconnecting link, grinding the disconnecting link by using a small file or a scraper like a grinding tile, smearing a ground surface by using a red marking pen after grinding, then installing a disconnecting link, repeatedly opening and closing the disconnecting link, checking the disconnecting link by using a highlight flashlight light transmission method after closing the disconnecting link, observing the contact surface after the disconnecting link is separated and the friction of the opening and closing link, wherein a lighting point is a high point, the red marking pen needs to be smeared again for switching-on operation, and the high point is ground or scraped at the red marking position of the contact surface of the disconnecting link without contact without grinding. The invention is used for an improved method based on excitation knife switch overheating or high-power knife switch overheating.)

1. An improvement method based on excitation switch overheating or high-power switch overheating is characterized by comprising the following steps: the method comprises the following steps:

(1) firstly, judging the size of a contact surface of a disconnecting link by adopting a highlight flashlight light transmission method, wherein the contact surface of the disconnecting link is less than 80%, disassembling a disconnecting link, grinding the disconnecting link by using a small file or a scraper like a grinding tile, smearing a ground surface by using a red marking pen after grinding, mounting the disconnecting link, repeatedly opening and closing the disconnecting link, checking the disconnecting link by using a highlight flashlight light transmission method after closing the disconnecting link, observing the contact surface after the disconnecting link is rubbed by the opening and closing link, wherein a lighting point is a high point, the red marking pen needs to be smeared again for switching on, and the high point is ground or scraped at the red mark part of the contact surface of the disconnecting link without contact until the contact surface is completely contacted or reaches more than 90%;

a. before the disconnecting link is processed, a contact surface of a moving contact is coated by a red marking pen, the disconnecting link is opened and closed for 3 times after coating, the contact surface after the disconnecting link is observed, the rubbed red part is the real contact surface of the disconnecting link, the size of the contact area between the moving contact and the static contact of the disconnecting link is judged, the contact surface is half, and the disconnecting link is overheated when in operation;

b. hanging the raised part by a scraper, smearing the part by a red marking pen, repeatedly opening and closing the switch for 3 times after reinstalling, observing whether the contact surface reaches 90%, repeatedly grinding the scraper until the contact area reaches the requirement, and if the contact area does not reach the requirement, carrying out silver plating or tin plating if the silver plating of the moving contact is damaged;

(2) the silver plating or tin plating scraped off after the knife switch piece is ground is wiped by dipping alcohol on cloth, the optimal temperature of the tin plating of an electric iron is 280 ℃ plus or minus 10 ℃ after the knife switch piece is heated by a baking target for flame welding, the temperature of the baking target for flame welding is controlled to be about 320-400 ℃, zinc chloride is smeared at a contact of the knife switch, then tin or silver is smeared, and the smeared knife switch piece is quickly wiped by pure cotton cloth;

(3) after the knife switch piece is installed, the contact surfaces of the lower opening of the knife switch piece and the upper opening of the knife switch piece are coated with the carbon brush of the generator to the movable contact and the static contact, so that the electrical conductivity is enhanced, the lubrication of the contact surfaces is increased, and then the resistance value is tested, so that the average value of the resistance value is within 28 microohm, the best maximum value is not more than 90 microohm;

(4) the disconnecting link and the bus are installed, the bus is installed on the rear side of the upper opening of the disconnecting link, and a bolt for connecting the disconnecting link and the bus is adjusted and used, so that the rear surface of the disconnecting link is just combined with the bus connecting bolt.

Technical Field

The invention relates to an improved method based on excitation knife switch overheating or high-power knife switch overheating.

Background

The temperature of the excitation disconnecting link reaches more than 100 ℃ when being high, the safe and stable operation of a unit is seriously threatened, the problem that the excitation disconnecting link is overheated, which is difficult to solve by a plurality of power plants, in the prior art, the excitation disconnecting link is replaced regularly by a method adopted by a plurality of power plants, and the excitation disconnecting link of the unit III is replaced in our factory, but the excitation disconnecting link is overheated after two years of operation; the resistance value is very high when the resistance value is measured, for example, the resistance value is up to 1330 micro blows when the No. 5 machine is overhauled, the contact surface between the lower opening of the disconnecting link and the static contact is seriously scaled and the dirt is very thick after the disassembly and the careful examination, and the combination surface including the connection surface of the static contact is thick; the knife switch and the bus are installed wrongly; the contact surface of the static contact and the moving contact of the disconnecting link does not reach the closing limit of the static contact, and the maximum difference reaches 12 mm; these all are the reasons that cause excitation switch overheated, and conventional processing is exactly to handle the problem that the design installation appears when leaving the factory one by one after the unit shuts down, perhaps changes excitation switch, changes excitation switch and mostly is the line contact, and traditional maintenance standard is to detect and detect through the instrument with the feeler gauge, detects with the feeler gauge shortcoming that the contact area of switch is little, also can't the precision measurement with the minimum feeler gauge of feeler gauge.

Disclosure of Invention

The invention aims to provide an improved method based on excitation disconnecting link overheating or high-power disconnecting link overheating, which does not need to replace a large number of excitation disconnecting links, can control the temperature below 70 ℃, saves the cost, and effectively improves the working efficiency and the service quality of the disconnecting links.

The above purpose is realized by the following technical scheme:

an improved method based on excitation knife switch overheating or high-power knife switch overheating comprises the following steps:

(1) firstly, judging the size of a contact surface of a disconnecting link by adopting a highlight flashlight light transmission method, wherein the contact surface of the disconnecting link is less than 80%, disassembling a disconnecting link, grinding the disconnecting link by using a small file or a scraper like a grinding tile, smearing a ground surface by using a red marking pen after grinding, mounting the disconnecting link, repeatedly opening and closing the disconnecting link, checking the disconnecting link by using a highlight flashlight light transmission method after closing the disconnecting link, observing the contact surface after the disconnecting link is rubbed by the opening and closing link, wherein a lighting point is a high point, the red marking pen needs to be smeared again for switching on, and the high point is ground or scraped at the red mark part of the contact surface of the disconnecting link without contact until the contact surface is completely contacted or reaches more than 90%;

a. before the disconnecting link is processed, a contact surface of a moving contact is coated by a red marking pen, the disconnecting link is opened and closed for 3 times after coating, the contact surface after the disconnecting link is observed, the rubbed red part is the real contact surface of the disconnecting link, the size of the contact area between the moving contact and the static contact of the disconnecting link is judged, the contact surface is half, and the disconnecting link is overheated when in operation;

b. hanging the raised part by a scraper, smearing the part by a red marking pen, repeatedly opening and closing the switch for 3 times after reinstalling, observing whether the contact surface reaches 90 percent, repeatedly grinding the scraper until the contact area reaches the requirement, and if the contact area does not reach the requirement, carrying out silver plating or tin plating if the silver plating of the moving contact of the disconnecting link is damaged;

(2) the silver plating or tin plating scraped off after the knife switch piece is ground is wiped by dipping cloth with alcohol, after the knife switch piece is heated by a baking target for flame welding, the optimum temperature of tin plating of an electric soldering iron is 280 degrees plus or minus 10 degrees, and the optimum temperature of the baking target for flame welding is controlled to be about 320-400 degrees. Coating zinc chloride on the contact of the disconnecting link, then coating tin or silver, and quickly wiping the coated disconnecting link by using pure cotton cloth;

(3) after the knife switch blade is installed, the contact surfaces of the lower opening of the knife switch blade and the upper opening of the knife switch blade are coated with the carbon brush of the generator to enhance the conductivity and increase the lubrication of the contact surfaces, and then the resistance value is tested, so that the average value of the resistance value is within 28 micro-blows, and the best value is not more than 90 micro-ohms.

(4) The disconnecting link and the bus are installed, the bus is installed on the rear side of the upper opening of the disconnecting link, and a bolt for connecting the disconnecting link and the bus is adjusted and used, so that the rear surface of the disconnecting link is just combined with the bus connecting bolt.

Has the advantages that:

1. the invention relates to an improved method based on excitation disconnecting link overheating or high-power disconnecting link overheating, by adopting the method, a large number of excitation disconnecting links do not need to be replaced, the temperature can be controlled below 70 ℃, the cost is saved, and the working efficiency and the service quality of the disconnecting links are improved.

2. The invention can judge which disconnecting link contact surface is unqualified by adopting a method of transmitting light by using the highlight flashlight, so that the inspection speed is high, the operation is simple and practical, and the method is more visual.

3. The invention adopts the technical scheme that the knife switch piece is detached and ground by a small file or a scraper, a ground surface is coated by a red marking pen after grinding, then the knife switch is installed, and the switch is repeatedly switched on and off.

4. The invention adopts the method that the cloth is dipped with alcohol to wipe the grinded silver or tin plating, the baking target for flame welding is used to heat the knife switch piece, the zinc chloride is smeared on the contact of the knife switch, and then the tin or silver is smeared, the knife switch piece after smearing is quickly wiped by the pure cotton cloth, and the method can ensure that the plated surface is very thin and bright.

5. The invention adopts the carbon brush of the generator to paint the moving contact and the static contact, and the method can play a role in lubricating, and simultaneously can also enhance the conductivity and enlarge the contact surface.

The specific implementation mode is as follows:

example 1:

an improved method based on excitation knife switch overheating or high-power knife switch overheating comprises the following steps:

(1) firstly, judging the size of a contact surface of a disconnecting link by adopting a highlight flashlight light transmission method, wherein the contact surface of the disconnecting link is less than 80%, disassembling a disconnecting link, grinding the disconnecting link by using a small file or a scraper like a grinding tile, smearing a ground surface by using a red marking pen after grinding, mounting the disconnecting link, repeatedly opening and closing the disconnecting link, checking the disconnecting link by using a highlight flashlight light transmission method after closing the disconnecting link, observing the contact surface after the disconnecting link is rubbed by the opening and closing link, wherein a lighting point is a high point, the red marking pen needs to be smeared again for switching on, and the high point is ground or scraped at the red mark part of the contact surface of the disconnecting link without contact until the contact surface is completely contacted or reaches more than 90%;

a. before the disconnecting link is processed, a contact surface of a moving contact is coated by a red marking pen, the disconnecting link is opened and closed for 3 times after coating, the contact surface after the disconnecting link is observed, the rubbed red part is the real contact surface of the disconnecting link, the size of the contact area between the moving contact and the static contact of the disconnecting link is judged, the contact surface is half, and the disconnecting link is overheated when in operation;

b. hanging the raised part by a scraper, smearing the part by a red marking pen, repeatedly opening and closing the switch for 3 times after reinstalling, observing whether the contact surface reaches 90 percent, repeatedly grinding the scraper until the contact area reaches the requirement, and if the contact area does not reach the requirement, carrying out silver plating or tin plating if the silver plating of the moving contact of the disconnecting link is damaged;

(2) the silver plating or tin plating scraped off after the knife switch piece is ground is wiped by dipping cloth with alcohol, after the knife switch piece is heated by a baking target for flame welding, the optimum temperature of tin plating of an electric soldering iron is 280 degrees plus or minus 10 degrees, and the optimum temperature of the baking target for flame welding is controlled to be about 320-400 degrees. Coating zinc chloride on the contact of the disconnecting link, then coating tin or silver, and quickly wiping the coated disconnecting link by using pure cotton cloth;

(3) after the knife switch blade is installed, the contact surfaces of the lower opening of the knife switch blade and the upper opening of the knife switch blade are coated with the carbon brush of the generator to enhance the conductivity and increase the lubrication of the contact surfaces, and then the resistance value is tested, so that the average value is within 20 micro-blows, and the best value is not more than 90 micro-ohms.

(4) The method comprises the steps that a disconnecting link and a bus are installed, the bus is installed on the rear side of an upper opening of the disconnecting link, a bolt used for connecting the disconnecting link and a busbar is adjusted and used, the bolt is just combined with a connecting bolt of the busbar behind a switch-on, if the length of the connecting bolt of the busbar is too long, the switch-on of the disconnecting link cannot be in place, six units are adopted, the bolt is too long due to installation errors of a manufacturer, the switch-on of the disconnecting link cannot be in place, and the maximum width of the disconnecting link reaching 12mm is 60 mm.

Specific examples are as follows:

by implementing the technical scheme, a power plant does not need to replace a large number of excitation disconnecting links, and the temperature is controlled below 70 ℃;

when the temperature of the excitation disconnecting link in the second and third periods of the power plant is high, two factors of more than 100 degrees are achieved: one reason is that contact surface contact is poor due to frequent operation, and a second manufacturer designs and installs problems to cause disconnecting link overheating, which seriously threaten the safe and stable operation of the unit, and the problem that the excitation disconnecting link is overheated is a very troublesome problem of many power plants, and the method adopted by many power plants is to replace the excitation disconnecting link regularly, and my factory also replaces the excitation disconnecting link of the third unit, but the operation is overheated for two years; the excitation disconnecting link is mostly in line contact, the previous maintenance standard is to use a feeler gauge for detection and carry out detection through an instrument, the feeler gauge is unreasonable in practice, the contact area of the disconnecting link is small, and the minimum feeler gauge of the feeler gauge cannot be used for accurate measurement;

1. the method of using the strong light flashlight to transmit light can judge which disconnecting link contact surface is unqualified, so that the inspection speed is high and the inspection is more intuitive;

2. it does not reach more than 80% to judge which switch contact surface according to highlight flashlight test, that position contact point is higher, because the unit all pulls open the switch when the maintenance is out of service, close excitation switch before opening the machine, because switch both sides have large-scale arch clamp pad to pass through screw fastening messenger switch moving contact to have certain tension, will cause certain damage to switch contact surface friction when closing the switch, because the switch adopts copper surface silvering or tin-plating, we know that these several kinds of metals are all very soft, closing the switch can cause to roll felt like friction and cause the bump will cause switch area of contact to reduce like this or the point contact, common high temperature before just appearing when the unit moves, harm unit safety and stability operation. The method that I take is to dismantle the knife switch piece and use the small-scale file, or the scraper grinds like grinding the tile, grind and once daub the abrasive surface with the red marking pen, install the knife switch again, divide and shut the brake once or twice repeatedly, reuse the bright flashlight photic method to check after closing a floodgate, dismantle and observe the contact surface after dividing and shutting the brake and rubbing, the luminous point is the high point, need daub the red marking pen and divide and shut the brake and observe and analyze and process the high point again, the knife switch contact surface that does not contact is red and still red to be regarded as, there is not ground here, the high point is ground and can't grind violently, it is thin with our common grinding tile, scrape or grind a bit, repeat many times, until the contact surface is totally contacted or reach above 90% stipulated so can guarantee the knife switch will not be overheated in service;

3. the scraped silver or tin after grinding is treated, if the silver or zinc plating I adopts the mode that firstly, a knife switch is wiped by using cloth dipped with alcohol, a baking target for flame welding is used for heating a knife switch piece, then zinc chloride is smeared at the contact of the knife switch, and then tin or silver is smeared, because the silver is expensive, most of I adopt the tin plating, and the tin or silver is quickly wiped by using pure cotton cloth immediately after smearing, so that the plated surface is very thin and bright, the tin plating is thick, the effect after grinding cannot be achieved due to unevenness, and the tin plating is also a very key step;

4. after the disconnecting link is installed, the moving contact and the static contact are coated by a carbon brush of a generator, so that the effects of lubricating, enhancing the conductivity and enlarging the contact surface can be achieved, a manufacturer usually adopts vaseline coating, vaseline is insulating and easy to accumulate dust, and a conductive paste is adopted, but the conductive paste has the defects of easiness in accumulating dust, the conductivity of the conductive paste is conductive when the voltage is higher than a certain value, the test is generally not successful by using a megger, and the excitation disconnecting link does not suggest to adopt the conductive paste;

5. if the upper complaint conditions are the same as the standards of original factories, the resistance value is measured very high, for example, when a No. 5 machine is overhauled, the highest value of the resistance value reaches 1330 micro, I suspects that the lower opening of the moving contact is not caused by scaling caused by conductive paste of the original factories for a long time, later, after disintegration and careful examination, the contact surface between the lower opening of the knife switch and the static contact is seriously scaled, the scale is very thick, the joint surface including the connecting static contact is thick, after the scale is cleaned, the lower opening of the knife switch and the contact surface of the upper opening of the knife switch are wiped by alcohol, and finally, the contact surfaces of the lower opening and the upper opening of the knife switch are coated by a carbon brush of a generator, so that the skill achieves the lubricating effect, and the good electric conduction performance and the scale formation which are not easy like vaseline oil can be achieved. Finally, the average resistance value is about 20 micro when resistance value test is carried out;

6. the excitation power distribution cabinet of the factory is of two factories of Nanrui relay protection and Nanrui electronic control, and the two factories have the same common fault or have design and installation defects. Firstly, the method comprises the following steps: the knife switch and the bus are installed wrongly; the contact surface of the static contact and the moving contact of the disconnecting link does not reach the closing limit of the static contact, and the maximum difference reaches 12 mm; the outgoing busbar is arranged in front of the joint of the upper opening of the disconnecting link and the busbar, and the busbar is arranged on the rear side of the upper opening of the disconnecting link; secondly, the method comprises the following steps: when the disconnecting link is switched on, the mechanical connecting part between the disconnecting link static contact and the insulating bakelite plate is just clamped at the part where the bolt grows out due to the fact that the bolt used for connecting the disconnecting link and the busbar is too long, and the further reason that the disconnecting link is overheated is caused as the result that the disconnecting link is not completely switched on in place and the contact surface is small.