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Create market with quality, develop with brand, and promote progress with technology

About us

Build a well-known brand of Chinese electrics, and promote the progress of electric technology and products

Taizhou Zhongda Electric Technology Co., Ltd. was founded in April 2008. The factory covers an area of 10,000 square meters and a building area of 7,000 square meters. It is located in the beautiful and rich Xiaoyumen Industrial Zone, Qianjiang Town, Yuhuan, Taizhou City. A professional manufacturer of electrical accessories such as high voltage switch accessories and circuit breaker accessories. The company takes quality as its lifeblood and maintains a good cooperative relationship with major domestic electrical companies. It follows strict management practices and meets customer demands in all aspects of material selection, manufacturing, and delivery. The company is currently in the development stage, constantly pursuing advancement in technology, and constantly supplementing resources to meet the needs of production. The company not only attaches importance to product quality, but also attaches importance to the management company's emphasis on people-oriented, giving full play to the enthusiasm and creativity of employees, so as to promote the harmonious development of employees and the company.

news information

Create market with quality, develop with brand, and promote progress with technology

08/30/2021

What are the measures to prevent oxidation of the contacts of high-voltage circuit breakers?

Due to the frequent operation of high-voltage circuit breakers, they often fail to trip due to mechanical and electrical factors. For the circuit breaker that has been put into operation, when the fault reappears on the load side of the circuit breaker, once a refusal trip occurs, it will inevitably cause skipping trips, expanding the scope of accidents and power outages, so it should be eliminated as soon as possible. The measures to reduce contact resistance and prevent contact oxidation are as follows: (1) Use materials with low resistivity and compressive strength to make contacts. (2) Use springs or spring pads to increase the pressure between the contact surfaces. (3) Plating a protective layer of tin, lead-tin alloy or silver on the surface of the easily oxidized copper, brass, and bronze contacts to prevent the contact resistance from increasing due to the oxidation of the contacts. (4) Coat the surface of the aluminum contact with a neutral petroleum jelly layer to prevent oxidation to cover it. (5) Use welded copper-aluminum transition joints. (6) In the structure of the breakable contact, there is a certain relative sliding between the moving and static contacts, and the oxide layer can be wiped off when opening and closing (called self-cleaning effect) to reduce contact resistance. DHL-100P intelligent loop resistance tester is based on the Ministry of Electric Power standard SD301-88 "AC 500KV Power Equipment Handover and Preventive Test Regulations" and the new version of "Power Equipment Preventive Test Regulations" to make contact resistance of circuit breakers and isolating switches. The measured DC current is not less than 100 as specified to ensure the accuracy of the test results. The loop resistance tester adopts the latest switching power supply technology, which can continuously output large current for a long time, overcomes the shortcomings of the pulsed power supply's instantaneous current, can effectively break down the switch contact oxide film, and obtain good test results.
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What are the measures to prevent oxidation of the contacts of high-voltage circuit breakers?
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08/30/2021

Reasons and treatment methods of high-voltage circuit breaker refusal to trip

Due to the frequent operation of high-voltage circuit breakers, they often fail to trip due to mechanical and electrical factors. For the circuit breaker that has been put into operation, when the fault reappears on the load side of the circuit breaker, once a refusal trip occurs, it will inevitably cause skipping trips, expanding the scope of accidents and power outages, so it should be eliminated as soon as possible. 1. Reasons for circuit breaker refusal to trip There are usually two reasons why the circuit breaker refuses to trip: one is the failure of the mechanical part of the operating mechanism, and the other is the electrical failure of the operating circuit. When the circuit breaker refuses to trip, the person on duty should first judge whether the trip circuit is intact according to the light indication. If the red light does not light up, it means that the trip circuit is blocked. At this time, check whether the operating fuse is blown or poorly contacted, whether the contact of the universal transfer switch and the auxiliary contact of the circuit breaker are poorly connected, whether the coil of the anti-trip relay is broken, whether the operating circuit is broken, whether the bulb or lamp is broken Wait intact. If the operating power is good and the tripping core is weak, it means that the tripping coil's operating voltage is too high, or the operating voltage is too low, the tripping core is jammed or detached, or the tripping coil itself is faulty. If the tripping iron core ejector rod is well transported and the circuit breaker refuses to trip, it may be that the mechanism is jammed or the drive connecting rod pin is detached. 2. Handling method for circuit breaker refusal trip After the reasons for the refusal to jump are ascertained, the personnel on duty should be calm and calm and adopt different solutions according to the nature of the failure. If the red signal light does not light up during the normal opening operation, after confirming that the lamp is in good condition, the operating fuse should be quickly replaced before the opening operation. At this time, it should be carried out by two persons, one person operating the change-over switch remotely, and the other person observing the action of the opening iron core on the spot, while keeping a safe distance. If the action of the iron core is weak, the iron core is blocking; if the opening iron core is operating normally, but the circuit breaker cannot be tripped, it means that the mechanical anti-jamming is indicated. At this time, a mechanical opening device should be used to interrupt the circuit breaker on the spot. For air circuit breakers and SF6 circuit breakers, the air pressure must be normal before the mechanism can be interrupted. When it is necessary to open the circuit breaker in an emergency situation, such as the operation of the relay protection device or the manual remote opening of the circuit breaker refused to open, which may cause damage to the main equipment, the person on duty should immediately open the upper-level circuit breaker manually, and then go to Use a mechanical opening device to interrupt the circuit breaker at the fault circuit breaker; if the mechanical opening device cannot open the circuit breaker, you should quickly open the isolation switches on both sides of the fault circuit breaker, and then restore the upper-level power supply. The cause is to be found out. Deal with it again; if the time permits in the accident state, the personnel on duty should quickly run to the fault circuit breaker and use a mechanical opening device to disconnect the circuit breaker; if the mechanical opening device cannot be used to open the circuit breaker, the operation mode should be changed immediately, or Use the bus tie circuit breaker and the upper-level circuit breaker to disconnect, and then use the isolating switch to isolate the fault circuit breaker and restore the operation mode. Therefore, it is recommended to use the DGK-S high-voltage switch dynamic characteristic tester to test the high-voltage circuit breaker on a regular basis in order to eliminate the fault in time. DGK-S high-voltage switch dynamic characteristic tester is a special high-voltage switch developed and produced by Dingsheng Electric Power Research and Development Center to adapt to the dynamic characteristics of various indoor and outdoor oil-less, multi-oil switches, vacuum switches, and sulfur hexafluoride switches. Dynamic characteristic tester, the internal processing of DGK-S high-voltage switch dynamic characteristic tester is based on the single-chip microcomputer as the core for sampling, processing and output. Its main function is to use Chinese character prompts and graphic displays to operate in a man-machine dialogue mode, which is simple and fast. It is suitable for testing the mechanical characteristics of all types and voltage levels of SF6 switches, GIS combined electrical appliances, vacuum switches, an
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Reasons and treatment methods of high-voltage circuit breaker refusal to trip
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08/30/2021

Key Technology of Intelligent High Voltage Switchgear

High-voltage switchgear refers to indoor and outdoor AC switchgear operating in power systems with a voltage of 3kV and above and a frequency of 50Hz and below. Mainly used for the control and protection of power systems (including power plants, substations, transmission and distribution lines, industrial and mining enterprises and other users). It can not only put part of power equipment or lines into or out of operation according to the needs of grid operation, but also can be used in power equipment or When the line fails, the faulty part is quickly removed from the power grid, so as to ensure the normal operation of the fault-free part of the power grid and the safety of equipment, operation and maintenance personnel. Therefore, high-voltage switchgear is a very important power transmission and distribution equipment, and its safe and reliable operation is of great significance to the safe and effective operation of the power system.
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Key Technology of Intelligent High Voltage Switchgear
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08/30/2021

What are the measures to prevent oxidation of the contacts of high-voltage circuit breakers?

Due to the frequent operation of high-voltage circuit breakers, they often fail to trip due to mechanical and electrical factors. For the circuit breaker that has been put into operation, when the fault reappears on the load side of the circuit breaker, once a refusal trip occurs, it will inevitably cause skipping trips, expanding the scope of accidents and power outages, so it should be eliminated as soon as possible. The measures to reduce contact resistance and prevent contact oxidation are as follows: (1) Use materials with low resistivity and compressive strength to make contacts. (2) Use springs or spring pads to increase the pressure between the contact surfaces. (3) Plating a protective layer of tin, lead-tin alloy or silver on the surface of the easily oxidized copper, brass, and bronze contacts to prevent the contact resistance from increasing due to the oxidation of the contacts. (4) Coat the surface of the aluminum contact with a neutral petroleum jelly layer to prevent oxidation to cover it. (5) Use welded copper-aluminum transition joints. (6) In the structure of the breakable contact, there is a certain relative sliding between the moving and static contacts, and the oxide layer can be wiped off when opening and closing (called self-cleaning effect) to reduce contact resistance. DHL-100P intelligent loop resistance tester is based on the Ministry of Electric Power standard SD301-88 "AC 500KV Power Equipment Handover and Preventive Test Regulations" and the new version of "Power Equipment Preventive Test Regulations" to make contact resistance of circuit breakers and isolating switches. The measured DC current is not less than 100 as specified to ensure the accuracy of the test results. The loop resistance tester adopts the latest switching power supply technology, which can continuously output large current for a long time, overcomes the shortcomings of the pulsed power supply's instantaneous current, can effectively break down the switch contact oxide film, and obtain good test results.
VIEW MORE →
What are the measures to prevent oxidation of the contacts of high-voltage circuit breakers?
VIEW MORE →

Servir

Create market with quality, develop with brand, and promote progress with technology

电话

Service Hotline

13750626488

0576-87453955

地址

Address

Xiaoyumen Industrial Zone, Ganjiang Town, Yuhuan City, Zhejiang Province

Tel：+86 18958585477

Add：Xiaoyumen Industrial Zone, Ganjiang Town, Yuhuan City, Zhejiang Province
E-mail：18958585477@163.com

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