1. Purpose
As a special accessory of the lightning arrester, the thermal explosion type release device is used in series with the lightning arrester to protect the safe operation of various 6kV-10kV distribution lightning arresters and 35kV-220kV line type gapless lightning arresters (including protective cables and power station type suspension installation). The working principle is to act promptly to remove the lightning arrester from the transmission system when it deteriorates, is about to explode, endangers electrical equipment and personal safety, and leads to a grounding short circuit causing switch tripping and power outage accidents. When the lightning arrester is working normally, the disconnector does not operate and is in a conductive state. After the release device is activated, it can provide clear identification for the faulty lightning arrester, making it easy to quickly release
At the current fault point, timely maintenance and replacement have been carried out to meet the maintenance free usage requirements of the lightning arrester, improving the stability and safety of the power system operation.
2. Scope of use
1. Power frequency not less than 48Hz and not exceeding 62Hz:
2. Altitude not exceeding 3000 meters:
3. Operating environment temperature -40 ° C to 50 ° C:
4. Suitable for outdoor use.
3. Definition of Detacher
A device that disconnects the lead wire of the lightning arrester from the system in case of a fault, in order to eliminate continuous system faults, and provides visible signs (partition gaps) of the faulty lightning arrester is called a disconnector. There is no ability to cut off the fault current, so it may not be possible to completely prevent 100% lightning arrester explosions. It can only be said to reduce the risk of lightning arrester explosions by more than 90%.
The detachable device has a history of more than ten years of use abroad, and it took nearly a decade for it to be used and manufactured domestically, and exported; It is used in conjunction with lightning arresters, fully leveraging the advantages of zinc oxide lightning arresters, making it an indispensable and necessary component for lightning arresters.
4. Type of release device
There are generally three types of disconnectors:
The first type is hot melt,
When a zinc oxide lightning arrester malfunctions, the main manifestation is an increase in the current flowing through the valve plate, causing the valve plate group to be in a heating state. Due to the negative temperature coefficient of the valve plate group, heating causes a decrease in equivalent resistance, which in turn intensifies heating and forms a vicious cycle. In this way, the working status of the lightning arrester is directly transmitted to the disconnector in the form of temperature, and the power frequency current is used to generate heat through itself. When this temperature reaches the design value of the disconnector, the low melting point alloy is melted, and the disconnector action causes the lightning arrester to detach from the grounding wire, cutting off the faulty lightning arrester from operation, and providing a clear signal to the inspection personnel, providing practical and feasible technical measures for achieving state maintenance of oxidation lightning protection.
Body.
The second type is thermal explosion,
When a zinc oxide lightning arrester malfunctions, the main manifestation is an increase in the current flowing through the valve plate, which utilizes the power frequency current to generate an arc and ignite the explosive, causing it to be inserted into the bolt and explode. The detachment action of the arrester separates the lightning arrester from the grounding wire, cutting the faulty lightning arrester out of operation, and providing a clear signal to the inspection personnel, providing practical and feasible technical measures for achieving "state maintenance" of the oxidation lightning arrester.
3、 The structure of the release device:
This article introduces the structure of the hot melt separator, please refer to the schematic diagram of the hot melt separator below. After the low melting point alloy melts, under the action of the spring force, the insertion end of the release device separates from the release device housing, achieving the purpose of being away from the power source.
4、 Characteristic parameters of the release device:
The disconnector does not operate when lightning current passes through, but quickly fuses and disconnects from the power supply when passing through power frequency current.
5. The advantages of detachers
The wide range of current, combined with the characteristics of China's power grid, can be disconnected under large power frequency fault currents (>50A) or under small fault currents (50mA).
（2） The fast detachment speed can be matched with the reclosing function of the circuit breaker, which is not only suitable for various voltage levels and types of lightning arresters, but also for different grounding systems (neutral grounded and ungrounded systems).
（3） Strong shock resistance and no action under 2ms square wave and 4/10 μ s high current shock.
（4） Before explosion, the TLB-5 has high mechanical strength and good sealing performance. It can be matched with lightning arresters below 35KV, The TLB-6 type can be used in conjunction with 35-220kV lightning arresters.
（5） Easy to install and replace threaded external interfaces, reliable and convenient for serial connection with lightning arresters, and extremely convenient for replacement once the disconnector is activated.
The detachable device is cheap, easy to replace, and brings safe and reliable operation.
6. Selection of release device
The general selection method is as follows: TLB-1 disconnector is selected for small grounding short-circuit current systems;
The TLB-2 disconnector is selected for the large grounding short-circuit current system.
7. Installation instructions
1. Lightning arresters with voltage levels of 10kV and below shall be installed on towing frames. The lightning arrester is fixed to the original installation position of the lightning arrester through a bracket, and the disconnector is installed on the lower terminal of the lightning arrester. Soft copper wire is used to connect the grounding point of the disconnector tower to ensure that the lightning arrester is installed properly
After separation, there is sufficient insulation distance.
2. 35kV~220kV line type gapless lightning arrester (including protective cables and power station type suspension installation, the disconnector is directly installed on the lower terminal of the lightning arrester, and the connecting wire is made of hard aluminum wire with a diameter of 10. The length is selected from 300mm~900mm according to different voltage levels (self provided), and connected to the high-voltage line, which can effectively prevent new fault hazards caused by the connection wire swaying after the disconnector is removed from position.
3. 35~110kV power station type lightning arrester (pedestal installation), the disconnector is connected to the high-voltage conductor through a wire clamp, and the disconnector is connected to the lightning arrester through braided soft copper wire.
4. The size of the upper screw hole and lower terminal of the disconnector can be related to the size of the lightning arrester wiring terminal.
8. Precautions for using the release device
The grounding end of the disconnector must be made of copper multi stranded flexible wire with a cross-sectional area greater than 10mm ².
The disconnector used in transmission line lightning arresters must be connected to the conductor (power supply end).
The installation of the disconnector and lightning arrester should not be on the same axis.
The installation of the disconnector should enable it to move freely and form sufficient air gaps, so that the damaged lightning arrester and system can be connected
