Surge Protector Installation Precautions - Six Points
1. Long-line oscillation effect: IEC61643-12 "Surge Protectors for Low Voltage Distribution Systems - Part 12: Selection and Use Guidelines" states: The impact of oscillation on the protection distance (called separation distance in some countries). When a surge protector is used to protect specific equipment or when the SPD located at the main distribution box cannot provide adequate protection for some equipment, the surge protector should be installed as close to the equipment to be protected as possible.
Impact of oscillation on protection distance: When a surge protection device is used to protect specific equipment or when the surge protector is installed on the main distribution board and cannot provide adequate protection for some equipment, the surge protector should be as close to the protected equipment as possible. If the distance between the SPD and the protected equipment is too long, the oscillation voltage value generated at the equipment end is generally as high as twice Up, and in some cases, even exceeds this level. Therefore, despite the installation of a surge protector, the oscillation phenomenon can still cause the protected equipment to fail.
GB18802.12 Section 6.1.2: In general, oscillations less than 10m away can be ignored. Sometimes the equipment has internal protection elements (e.g., ZnO varistors), which will significantly reduce the oscillation even over long distances. In the last case, care should be taken to avoid coordination problems between the SPD and the internal protection elements of the equipment.
2. GB50343-2012) Section 5.4.3.8: When the power line is installed at various locations, the connecting wires of the surge protector should be short and straight, and the total length should not be greater than 0.5m. The effective protection level Up/f should be less than the equipment's impulse withstand voltage rating Uw. As shown in the figure below:
3. GB50343 Section 6.5.1.3: The minimum cross-sectional area of the connecting wire of the surge protector should comply with the provisions of Table 6.5.1.
4. GB50343-2012 Section 5.4.3.10: When multiple surge protective device are set on a line, the energy coordination between them should be considered. Article 5.4.3.6 stipulates: When the line length between the voltage switch type surge protector and the voltage limiting type surge protector is less than 10m, and the line between the voltage limiting type surge protectors is less than 5m, a decoupling device should be installed between the two levels of surge protectors. When the surge protector has the function of automatic energy matching, the line length between the surge protectors is not limited.
5. Select appropriate SPD and SSD according to the protected equipment and location.
6. Safe and effective grounding and reasonable wiring.
