The reason why the leakage protector of the LED display power supply system frequently trips

1. Unreasonable layout of leakage protector

Due to the particularity of the 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, and the inevitable misoperation and refusal of the leakage protector itself, coupled with the failure to arrange the leakage protector according to the actual power consumption, the total leakage protector frequently trips.

In addition to strengthening management, it is also necessary to arrange the leakage protector reasonably from a technical perspective according to the actual situation. The leakage protector on the incoming main power supply can be mainly used as a total protection to prevent electrical fire hazards and electrical short circuits, and also as a backup protection for each small leakage protection range. Its rated leakage action current can be selected between 200 and 500mA, and the rated leakage action time can be selected between 0.2 and 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 total leakage protector action can be improved. If the secondary leakage protection within each leakage protection range can be in an effective protection state, the frequent tripping probability of the total leakage protection device on the construction site can be greatly reduced.

2. No effective secondary or tertiary leakage protection is formed within the protection range .

The final leakage protection device in the switch box is the main protection of the electrical equipment. If the final leakage protection device is not installed, damaged or improperly selected, it may cause the upper leakage protection device to trip frequently. Since there are many metal conductors and many wire joints in the LED display screen, if the wire insulation is not very good, it will cause frequent leakage; some sockets are added, and leakage protection devices are not installed in many cases, which often causes leakage. Only by forming an effective secondary or tertiary leakage protection mode within each protection range can the frequent tripping of the leakage protection device be effectively reduced.

3. The leakage protection device itself has certain limitations

(1) The current leakage protection devices, 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 the three-phase or three-phase four-wire in the magnetic ring in a completely balanced manner. The three-phase power 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 magnetic permeability. When this electromotive force is large enough, it will cause the leakage protector to trip. Since the leakage protector with a larger rated current uses a relatively large magnetic ring, the leakage flux generated is also relatively large, and the leakage current must overcome the magnetizing force of the magnetic ring itself. As a result, the larger the rated current of the leakage protector actually used, the lower the sensitivity and the greater the rejection rate.

(2) The leakage protector has an action uncertainty region between the rated leakage action current and the rated leakage non-action current. When the leakage current of the leakage protector fluctuates in this region, it may cause the leakage protector to trip irregularly.

4. Improper selection of leakage protector

(1) The rated leakage action current used in the switch box exceeds 30mA or exceeds twice the rated current of the electrical equipment, or a leakage protector with a delay type is selected. Due to the increase in the rated leakage action current or the decrease in protection sensitivity, when a leakage fault occurs, the final leakage protector does not operate, and the upper leakage protector may operate. (2) The starting current when the LED display screen is powered on is often relatively large, and this large current may cause the leakage protector to trip. Therefore, the display

box should be powered on in batches as much as possible . In addition, an electromagnetic leakage protector that is not very sensitive to surge overvoltage and overcurrent should generally be selected; or an electronic leakage protector that is 1.5 to 2 times larger than the rated current should be selected, but as the final leakage protection, the rated leakage action current should not be greater than 30mA. In short, the frequent tripping of the leakage protector is the result of the combined effect of various factors. The most important thing is to arrange the leakage protector reasonably, narrow the protection range of the second or third level leakage protector, correctly select the leakage protector and wiring, so that the second or third level leakage protector in each range is 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-electrician wiring. This can not only improve the safety of electricity use, but also reduce the frequent tripping of the leakage protector, creating better power supply conditions for the normal operation of the LED display.