The traditional protection method uses an electromagnetic tripping circuit breaker. When a short circuit is detected, the tripper operates, and the breaking time is at the millisecond level, which cannot effectively suppress the short-circuit current. A better way is to use current limiting technology and devices with fast response speed.
1. Main functions of electrical fire protection current-limiting protector
1) Short-circuit current limiting: When a short-circuit fault occurs on the line, rapid current-limiting protection can be achieved to suppress excessive short-circuit current. Electrical fire accidents caused by large places.
2) Overload current limiting: When the current of the protected line exceeds the rated current, the line is overloaded and the overload duration exceeds the set time, the protector performs current limiting protection.
3) Over-temperature current limiting: When the temperature of the internal components of the protector exceeds the set value, the product activates the over-temperature current limiting protection function to prevent product damage due to excessive temperature.
4) Over/under-voltage protection: When the protector detects under-voltage or over-voltage of the line voltage, the protector sends out an audible and visual alarm signal, and whether to activate current limiting protection can be preset.
5) Cable temperature monitoring: When the temperature of the monitored cable exceeds the alarm setting value, the protector will send out an audible and visual alarm signal, and you can pre-set whether to activate the current limiting protection.
6) Leakage current monitoring: When the leakage of the monitored line exceeds the alarm setting value, the protector will send out an audible and visual alarm signal, and it can be preset whether to activate the current limiting protection.
7) Communication function: data can be sent to the background monitoring system to achieve remote monitoring. The monitoring background can be an electrical fire monitoring host, a smart power safety cloud platform, or a third-party monitoring software or platform.
Electrical fire monitoring system
2. Misunderstandings in the design and use of current-limiting protectors:
1) Current-limiting protectors have small current products. I thought that we could have high-current products, so in order to reduce the number of uses during design, we tried to choose high-current products as much as possible.
The short-circuit protection function of the current-limiting protector should comply with the requirements of graded protection. The larger the current, the worse the arc extinguishing effect of the terminal short-circuit;
When the line is short-circuited, minimize the Outage range.
2) Since the current-limiting protector is used in terminal line protection, it must be installed in the terminal distribution box.
The current-limiting protector uses a solid-state switch, which consumes a certain amount of power and generates heat during normal operation. It should not be installed in a confined space.
3. The difference between current-limiting protectors and traditional micro-breakers:
1) Current-limiting protectors are also called arc-extinguishing protectors in some cases, so sometimes It is easy to be confused with arc fault detectors, but the current-limiting protector is mainly used for rapid shutoff after a fault short circuit. It is equivalent to an enhanced version of the instantaneous tripping function of the air switch and is a post-event protection.
2) The arc fault detector detects abnormal conditions and hidden dangers in the line in a timely manner by monitoring the series and parallel arc faults in the access line. Its main function is to provide prior protection.
3) Current-limiting protectors and arc fault detectors can be used together.
4. Current-limiting protector - application places
Schools, hospitals, shopping malls, hotels, residences, kindergartens, buildings for the elderly, warehouses, electric vehicle charging stations, rental shopping malls Shops, temples, cultural relics buildings, exhibitions, dormitories, entertainment venues, wholesale markets, Class A, B and C dangerous goods warehouses, etc.