1. The layout of the leakage protector is unreasonable
Due to the particularity of the installation site of the full-color LED display of the distribution box, such as wiring errors, line damage, damage to the leakage protector in the switch box, and some electrical appliances not passing through the switch box, etc., and the leakage protector itself is inevitable Misoperation 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, Seejue Optoelectronics also needs 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 0.2~0.3s. 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 in an effective protection state, the frequent tripping probability 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 selected improperly, it may cause the upper-level leakage protector to trip frequently. Since there are many metal conductors in the LED full-color display screen and there are many wire connectors, if the wire insulation is not very good, it will cause frequent leakage. Some sockets are added, and leakage protectors are not installed in many cases. Cause leakage.
¡¡¡¡3, the leakage protector itself has certain limitations (three-phase electricity is unbalanced)
¡¡¡¡ The current leakage protectors, whether electromagnetic or electronic, use magnetic induction voltage transformers to pick up the leakage current in the main circuit of 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 electricity load of the LED full-color electronic 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. This electromotive force is 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 actual leakage protector , The lower the sensitivity, the greater the rejection rate.
¡¡¡¡ There is a certain area of operation uncertainty between the rated leakage current and the rated non-operation current of the leakage protection device. When the leakage current of the leakage protection device fluctuates in this area, it may cause the leakage protection device to trip irregularly.
¡¡¡¡4, the selection of leakage protector is unreasonable
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 a leakage protector with a delay type is selected, due to the increase or protection of the rated leakage action current When the sensitivity drops and a leakage fault occurs, the last-stage leakage protector does not operate, and the upper-stage leakage protector may operate.
¡¡¡¡Vision Optoelectronics reminds that the starting current when powering on the large LED screen 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.