Due to the peculiarities of the full-color LED display installation site, such as wiring errors, line damage, damage to the leakage protector in the switch box, some electrical appliances not passing through the switch box, etc., and the inevitable malfunction of the leakage protector itself And refusal to operate, coupled with the failure to arrange the leakage protector according to the actual electricity consumption, resulting in frequent tripping of the total leakage protector.
1. The layout of the leakage protector is unreasonable
Due to the peculiarities of the full-color LED display installation site, such as wiring errors, line damage, damage to the leakage protector in the switch box, some electrical appliances not passing through the switch box, etc., and the inevitable malfunction of the leakage protector itself And refusal to operate, coupled with the failure to arrange the leakage protector according to the actual electricity consumption, resulting in frequent tripping of the total leakage protector.
In addition to strengthening management for this situation, it is also necessary to rationally arrange the leakage protector according to the actual situation from a technical point of view. The leakage protector on the main power supply of the incoming line can be mainly used as a total protection to prevent electrical fire hazards and electrical short circuits. It also serves as a backup protection for each small leakage protection range. Its rated leakage current can be between 200 and 500 mA. Choose between, the rated leakage action time can be 0.20.3s. In this way, the influence of surge voltage, surge current, and electromagnetic interference on the total leakage protector can be greatly reduced, and the selectivity and reliability of the operation of the total leakage protector can be improved. If the secondary leakage protection in each leakage protection range can be in an effective protection state, the frequency of frequent tripping of the total leakage protector on the construction site can be greatly reduced.
2, there is no effective secondary or tertiary leakage protection in the protection range
The last-stage leakage protector in the switch box is the main protection of electrical equipment. If the last-stage leakage protector is not installed, damaged or incorrectly selected, it may cause the upper-level leakage protector to trip frequently. Since there are many metal conductors in the full-color LED display, and there are many wire connectors, if the wire insulation is not very good, it will cause frequent leakage; some sockets are also added, and in many cases, leakage protectors are not installed. Cause leakage. Only when an effective secondary or tertiary leakage protection mode is formed in each protection range, can the frequent tripping of the leakage protector be effectively reduced.
3, the leakage protector itself has certain limitations
(1) The current leakage protectors, whether electromagnetic or electronic, use magnetic induction voltage transformers to pick up the leakage current in the main circuit of the electrical equipment. It is impossible to arrange three-phase or three-phase four-wire in the magnetic ring to be completely balanced. The three-phase power load of the full-color LED display cannot be completely balanced. Under high current or high overvoltage, a certain electromotive force will be induced in the magnetic ring with high permeability, which is so large To a certain extent, it will cause the leakage protector to trip. Since a leakage protector with a larger rated current uses a relatively large magnetic ring, the leakage flux generated is relatively large, and the leakage current must overcome the magnetizing force of the magnetic ring itself, resulting in a larger rated current of the leakage protector in actual use , The lower the sensitivity, the greater the rejection rate.
(2) There is an uncertain area between the rated leakage current and the rated non-operation current of the leakage protector. When the leakage current of the leakage protector fluctuates in this area, it may cause the leakage protector to trip irregularly.
4, the selection of leakage protector is unreasonable
(1) The rated leakage action current used in the switch box exceeds 30mA, or is more than twice the rated current of the electrical equipment, or the leakage protector with time delay is selected, due to the rated leakage action current Increase or decrease of protection sensitivity, when a leakage fault occurs, the last-stage leakage protector does not act, and the upper-stage leakage protector may act.
(2) The starting current when energizing the full-color LED display is often relatively large, and this large current may trip the leakage protector. Therefore, the cabinets of the display should be electrified in batches as much as possible. In addition, in general, an electromagnetic leakage protector that is not sensitive to surge overvoltage and overcurrent should be selected; or an electronic leakage protector that is 1.5 to 2 times larger than the rated current, but as the final leakage protection, rated leakage action The current should not be greater than 30mA.
In short, the frequent tripping of the leakage protector is the result of various factors. The most important thing is to arrange the leakage protector reasonably, reduce the protection range of the second or third level leakage protector, and correctly select the leakage protector and wiring to make each The second or third-level leakage protectors within the scope are in an effective protection state; on the other hand, it is to strengthen electricity management and improve the quality of electricity users through training, and eliminate non-electrical wiring, so that the safety of electricity can be improved, It can also reduce the frequent tripping of the leakage protector, and create better power supply conditions for the normal work of the full-color LED display.
