How to solve the problem of frequent tripping of the LED display total leakage protector?
1. The layout of the leakage protector is unreasonable
Due to the particularity of the installation site of the LED display, such as wiring errors, line damage, damage to the leakage protector in the switch box, some electrical appliances did not pass through the switch box, and the inevitable misoperation and rejection In addition to failing to arrange the leakage protector according to the actual electricity consumption situation, the total leakage protector frequently tripped.
For this situation, in addition to strengthening management, it is also necessary to arrange the leakage protector from a technical perspective and according to the actual situation. The leakage protector on the main power supply of the incoming line can be used as a general protection against electrical fire hazards and electrical short circuits, and also as a backup protection for each small leakage protection range. Its rated leakage current can be between 200 and 500mA Choose between time, the rated leakage action time can choose 0.2 ~ 0.3s. In this way, the impact 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 effectively protected, the probability 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 within the scope of protection
The last-stage leakage protector in the switch box is the main protection of the electrical equipment. If the last-stage leakage protector is not installed, damaged or improperly selected, it may cause the upper-level leakage protector to trip frequently. Because there are many metal conductors in the LED display, there are many wire connectors. If the wire insulation is not very good, it will cause frequent leakage; some also add some sockets, and often do not install leakage protectors, often causing leakage . Only the formation of effective secondary or tertiary leakage protection mode within each protection range can effectively reduce the frequent tripping of the leakage protector.
3. The leakage protector itself has certain limitations
(1) Current leakage protectors, whether electromagnetic or electronic, use magnetic induction voltage transformers to pick up leakage currents in the main circuit of electrical equipment. Three-phase or three-phase four-wires cannot be completely balanced in the magnetic ring. The three-phase electrical load of the LED display screen 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 large enough to a certain extent , It will cause the leakage protector to trip. Because the leakage protector with a larger rated current uses a relatively large magnetic ring, the leakage magnetic flux generated is also relatively large, and the leakage current must overcome the magnetizing force of the magnetic ring itself, resulting in a larger rated current of the actual leakage protector. The lower the sensitivity, the greater the rejection rate.
(2) The leakage protector has an uncertain area of operation between the rated leakage operating current and the rated leakage non-operating current. When the leakage current of the leakage protector fluctuates in this area, it may cause the leakage protector to trip irregularly.
4. Unreasonable selection of leakage protector
(1) The rated leakage action current used in the switch box exceeds 30mA or exceeds two times the rated current of the electrical equipment, or a leakage protection device with a delay type is selected. Due to the rated leakage action current Increase or decrease in protection sensitivity. When a leakage fault occurs, the last-stage leakage protector does not operate, and the upper-stage leakage protector may operate.
(2) The starting current when the LED display is energized is often relatively large, and this large current may cause the leakage protector to trip. Therefore, the cabinets of the display screen should be powered up in batches as much as possible. In addition, generally use electromagnetic leakage protectors that are not sensitive to surge overvoltage and overcurrent; or use electronic leakage protectors that are 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 reasonably arrange the leakage protector, reduce the protection scope of the second or third-level leakage protector, and correctly select the leakage protector and wiring to make each The secondary or tertiary leakage protectors within the scope are in an effective protection state; on the other hand, it is to strengthen the management of electricity use and improve the quality of electricity users through training, and to eliminate non-electrical wiring, so as to improve the safety of electricity use. It can also reduce the frequent tripping of the leakage protector and create better power supply conditions for the normal operation of the LED display screen.
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