The arrester is connected between the cable and the ground, usually in parallel with the device being protected. The lightning arrester can effectively protect communication equipment, once there is an abnormal voltage, the lightning arrester will take action, play a protective role. When communication cables or equipment are in the normal operating voltage operation, the arrester will not have a role in the ground as a circuit breaker. Once there is a high voltage, and endanger the insulation of the protected equipment, the arrester immediately action, the high voltage impulse current directed to the earth, to limit the voltage amplitude,...

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In the normal operation of the voltage transformer, the probability of its internal failure is very small. The high-voltage fuse is often blown because of the resonance of the voltage transformer. When the operation mode of the system changes in some way, the iron core of the voltage transformer is saturated, the inductance and capacitive reactance to the ground are equal or approximately equal, and a relatively large current is generated, causing the fuse to blow. At this time, the voltage transformer must be shut down. Replace the fuse.   What we are now using is a quartz sand-filled porcelain tube fuse...

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The ±1100 kV line has 4 base towers with DC arresters installed, 3 bases are located in Gansu, and the other is located in Haiyuan County, Ningxia. The DC arresters installed on the towers are the only set of high-voltage line arresters in Ningxia Power Grid. Since a single lightning arrester weighs 3 tons and the tower is in a cornfield, the cost of using a crane to experiment is relatively high and there are significant safety hazards. For this reason, State Grid Ningxia Electric Power tried for the first time to carry out DC reference voltage and leakage current...

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Fuse cutout can be divided into high voltage fuse cutout and low voltage fuse cut out according to the service voltage.  It can be divided into dropout fuse for protecting transformers and general electrical equipment,  for protecting voltage transformers, for protecting power capacitors, for protecting semiconductor components, dropout fuse for protecting motors, and dropout fuse for protecting household appliances, etc. According to the structure can be divided into open type, semi-closed type, pipe type, and jet type fuse cutout   The rated current of the fuse link is not equal to the rated current of the whole fuse cutout. The rated current of...

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The test items of suspension insulators and post insulators shall include the following: Measure the insulation resistance of the insulator; AC withstand voltage test of insulators. The insulation resistance value of the insulator shall meet the following requirements: The insulation resistance value of suspension insulators used for voltage levels of 330KV and below should not be less than 300MΩ; for suspension insulators used for voltage levels of 500kV, it should not be less than 500MΩ; The insulation resistance value of post insulators with voltage levels of 35kV and below shall not be lower than 500MΩ; Use Dingsheng Power DC2403...

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Composite insulators were developed 45 years ago, largely due to these defects, and were introduced on an industrial scale in the 1980s. When suppliers adjust their products through successive generations of designs based on their initial service experience, there is a learning curve, but the technology is now mature. In fact, in most countries, it is considered equivalent and interchangeable with porcelain and glass. This is an impressive achievement, especially if one thinks that 25 years ago, power engineers knew little about the technology and did not trust composite insulators.

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With the increase of operating time of 500 kV substation equipment, the pollution degree of pillar insulators becomes more and more serious. The creepage of the insulators is more and more obvious, and the discharge sound increases on rainy and foggy days. Regular cleaning or emergency cleaning of insulators is an extremely effective anti-pollution flashover measure. In response to the requirements of high equipment reliability, there are fewer opportunities for power outage maintenance. At the same time, with the advancement of state maintenance work, there are fewer opportunities for equipment power outages. The hidden danger of flashover threatens the safe...

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Measuring the voltage distribution (or zero checks) of suspension insulators and multi-element pillar insulator strings is one of the methods to check for degraded insulators. It is carried out without power failure. (1) Characteristics of voltage distribution on the insulator string The voltage that each element in the suspension insulator string bears is different. This is mainly due to the capacitance between the metal part of the insulator and the ground, the cross arm or the tower, and the point wire, which makes the voltage distribution of the insulator string Very uneven. The voltage drop on the insulators closer to the wire...

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A new type of product that fills the gap in the field of online water-repellency testing of composite insulators in my country. The structure is simple, the operation is convenient, and the judgment is accurate. It is suitable for online detection of the hydrophobicity of 110kV and above transmission line composite insulators. It is also suitable for the hydrophobicity detection experiment and factory inspection of various composite insulators and silicone rubber. It is suitable for the water repellency detection of RTV spraying materials for magnetic insulators. Detection principle The water-repellent state of composite insulators is judged according to the water spray...

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(1) First fix the base of the lightning arrester, and then install each unit (section) of the lightning arrester in groups from bottom to top. (2) The arrester has passed the assembly test and qualified before leaving the factory. The on-site installation should be strictly assembled according to the manufacturer's number, and can not be exchanged to avoid the change of characteristics. (3) the valve type arrester with series and combined current negative should be selected during installation so that the nonlinear coefficients between the same phase combination units are close to each other, and the difference value should not be greater...

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