Selection And Installation Guidelines For Surge Protectors In Industrial Electrical Equipment
I.Introduction
Surge protectors are protective devices widely used in industrial electrical equipment, primarily designed to effectively guard against surge phenomena such as voltage spikes and current transients within electrical systems. Since surges are unavoidable during electrical system operation, selecting appropriate surge protectors and ensuring their correct installation and commissioning are crucial for maintaining the stability and safety of electrical systems.
II.surge protective device Selection
1.Rated Voltage of Surge Protectors（Uc）
The rated voltage is one of the most critical parameters when selecting surge protectors, as it determines the scope of protection. In industrial electrical equipment, the appropriate rated voltage should be chosen based on factors such as system voltage magnitude, operating environment, and equipment criticality. Generally, the rated voltage should exceed 1.2 times the system's peak voltage.
2.surge protector Nominal Discharge Current（In）
The rated current of a surge protector indicates the maximum current it can withstand. In industrial electrical equipment, the appropriate rated current should be selected based on the actual current levels. If the rated current is too low, the protector cannot handle overcurrents in the electrical system; conversely, an excessively high rated current may cause system malfunctions.
3.Surge Protector Maximum Discharge Current（Imax）
The discharge current of a surge protector refers to the maximum discharge current it can withstand when a surge arrives. In industrial electrical equipment, the appropriate discharge current should be selected based on factors such as the system operating environment and equipment criticality. If the discharge current is too low, it cannot withstand surges in the electrical system; conversely, if the discharge current is too high, it may cause the protector itself to fail.
4.Response Time of Surge Protectors（tA）
The response time of a surge protector refers to the duration from surge onset to discharge initiation. In industrial electrical equipment, surge protectors with the shortest possible response time should be selected. Protectors with prolonged response times cannot effectively withstand transient surges in electrical systems, potentially causing system failures.surge protection device response time less than 25 nanoseconds.
III.Key Installation Considerations for Surge Protectors
1.Installation Location of Surge Protectors
The installation location of surge protectors should be determined based on the specific electrical system design. Generally, it is recommended to install surge protectors on the power supply side of electrical equipment to ensure effective protection for the entire electrical system.
2.Connection Between Surge Protectors and Grounding
Surge protectors must be properly grounded to ensure the safety of the electrical system. The grounding electrode should be buried underground, specifically below ground level or the water table, to guarantee stable and reliable grounding.
3.Cable Length Limitations
Due to the inherent impedance characteristics of cables, current fluctuations within the cable can cause signal reflection and generate return voltage, potentially affecting the system. Therefore, when installing surge protectors, cable length should be limited according to the manufacturer's specifications.
4.Testing of Surge Protectors
After installing surge protectors, necessary testing must be conducted to verify proper operation. Concurrent testing of the electrical system should also be performed to ensure overall stability and safety.
IV.Conclusion
Selecting appropriate surge protectors and performing correct installation and commissioning are crucial for the stability and safety of industrial electrical equipment. When choosing surge protectors, they should be selected based on actual requirements and the characteristics of the electrical system, followed by proper installation and commissioning to effectively ensure the stability and safety of the electrical system.
