The configuration principle of transformer low-voltage side surge protector is to choose a first level surge protector!
Recently, a customer inquired about the selection of surge protectors for low-voltage distribution rooms in transformers. They felt that the other side of the transformer was connected to a high-voltage line, which posed a high risk of lightning strikes. Therefore, they believed that surge protection at this location should be given special attention.
So, how should the low-voltage side surge protector of the transformer be configured? Mainly including the following points:
1. The power line is introduced into the incoming cabinet from the low-voltage side of the outdoor transformer. According to the lightning protection design zoning concept, it enters the LPZ1 area from the LPZO area. Therefore, according to lightning protection standards, surge protectors for level i testing should be installed on the busbar. When the lightning protection testing unit conducts lightning protection acceptance, it will also check whether the surge protector at this location meets the requirements of Class T1 first level surge.
2. If the surge protector on the low-voltage side of the transformer is set between the transformer and the outlet circuit breaker, when the outlet circuit breaker is in the open position, the protection of the surge protector is missing on the low-voltage distribution panel busbar. Therefore, the setting position of surge protectors should be reasonably considered to ensure that they can still function when the circuit breaker is opened.
3. The surge protector should be configured in a dispersed multi-level configuration. The purpose of multi-level configuration is to release the energy of direct lightning strikes, limit the amplitude of induced overvoltage voltage, and protect the equipment of the power terminal distribution box. This configuration method can better protect the circuit and prevent damage to the equipment caused by surge currents. Specifically, it can be divided into three levels of protection: the first level of protection is installed between the LPZO and LPZ1 zones in the lightning strike area, in front of the distribution box of the main power supply incoming line; The second level of protection is installed between Zone 0 and Zone 1 in the lightning strike area, in front of the UPS or distribution box; The third level of protection is installed in parallel behind the air switch in the power terminal distribution box. The maximum discharge current and operating time of each level of protector also vary, and selection needs to be made according to the actual situation.
4. The surge protector of the low-voltage distribution system in the substation should be installed on the busbar of the low-voltage distribution cabinet and closely adjacent to the low-voltage outlet circuit breaker of the transformer. This can ensure that the surge protector can effectively function and protect the circuit from damage caused by surge currents.
When configuring the low-voltage side surge protector of a transformer, it is necessary to consider factors such as the specific situation of the building, line layout, voltage protection level, etc., to ensure that the surge protector can effectively function and protect the circuit and equipment from overvoltage damage such as lightning. In the actual configuration process, it is recommended to consult a professional electrical engineer to ensure that the configuration scheme complies with relevant specifications and standards.
