High voltage fuse

A high-voltage fuse is an electrical appliance that uses an overload or short-circuit current to fuse the melt, and then relies on the arc extinguishing medium to extinguish the arc to break the circuit. The main function of a high-voltage fuse is to protect the equipment in the circuit when it is short-circuited, and sometimes it can also be used as overload protection. It is usually composed of melt, fuse tube, arc extinguishing medium, contact, post insulator and base. Commonly used melts are wires or sheets of copper and silver. Commonly used arc extinguishing media include air, steel paper, and quartz sand.

Outdoor high-voltage fuses are mainly drop-open fuses, which are widely used in 3-35KV and rated current 1-200A occasions, and can be used for overload and short-circuit protection of lines or transformers. Generally, it is installed on a rod. Its working principle is that when the melt passes through an overload or short-circuit current, the fuse is quickly blown to form an arc. The fibrous arc extinguishing tube decomposes a large amount of gas due to the arc burning, which causes the pressure in the tube to increase sharply. Strong longitudinal arc blowing. After the fuse is blown, the upper contact of the fuse tube turns down due to the loss of tension, so that the locking mechanism releases the fuse tube. Under the action of the fuse tube's own weight and the contact elasticity, the fuse tube falls open, causing an obvious breaking point.

Main features of indoor current-limiting fuse

1. High breaking capacity: rated breaking current is 31.5kA-50kA

2. Low power loss: low temperature rise. This feature is more prominent when the fuse is working in the middle of a fully enclosed insulator device.

3. Low arc voltage: The arc voltage is low during the breaking process.

4. The characteristic curve error is small: the time-current characteristic curve error is less than ±10%.

5. Standardization of specifications: The rated parameters of the product conform to the R10 and R20 series of IEC standards of the International Electrotechnical Commission.

6. It can be equipped with an impactor. The impactor connected in parallel with the melt can act within a few thousandths of a second from the beginning of the arc and give a signal with enough energy to make other electrical appliances operate or provide interlocking. The output energy of the fuse striker that meets the German DIN standard is 3 to 5 joules.

7. It has a great current limiting effect. In this way, when selecting the conductor of the protected component, you only need to design according to the limiting current value instead of the full short-circuit current value, which can save conductive materials and other materials.