If the high-value information power electronic products in the building, their ability to withstand lightning surges is much smaller than that of basic electrical equipment, it is necessary to use a surge protector to maintain such high-precision electronic products, then how to choose a surge What about protectors?
Before selecting a surge protector, be sure to carry out a lightning strike risk assessment and take into account the economics of the project, not only direct losses, but also indirect damage (for information management systems, indirect damage is usually higher than In addition, the relevant laws and regulations today require the installation of surge protectors, such as national industry standards such as GB 50057. Below, I will explain how to choose a surge protector from multiple levels.
In order to better ensure that complex power supply systems and information systems will not be harmed by direct lightning strikes and surges, IEC 62305 clearly defines the definition of lightning protection zones.
LPZ 0A: Exposure to direct lightning strikes, bearing all lightning currents and all lightning electromagnetic fields.
LPZ 0B: Protection against direct lightning strikes, withstanding partial lightning current or induced current, and full lightning magnetic field.
LPZ 1: Protection against direct lightning strikes, local lightning currents or induced currents, and attenuated lightning magnetic fields. The surge is limited to being shunted at the boundary and protected by a surge protector, and the electromagnetic field has spatially shielded attenuation.
LPZ 2…n: Similar to LPZ 1, but with further attenuation of the electromagnetic field for lightning strikes. As a general protection rule, the protected object should be placed in the LPZ zone whose electromagnetic properties are compatible with the ability to withstand damage to reduce damage (physical damage, failure of electrical and electronic systems due to overvoltage, etc.
How to choose the corresponding surge protector
When it is impossible to measure the class 1 surge protector (Type1, Class1), Iimp≥12.5kA is generally used, that is to say, 12.5kA is sufficient in most situations. We recommend using Iimp=25kA, so that there will be The larger the capacity, the longer the service life.
For class 2 surge protectors (Type2, Class2), we choose to apply 20/40kA (In=20kA, Imax=40kA) power surge protectors, and lightning strikes above 40kA (after LPZ1) are rarely generated in specific applications. of. There are many types of Class 2 surge protectors, including 40/80kA, 50/100kA, and 60/120kA power surge protectors.
Meet the safety requirements in three working states
1. Waiting state: voltage aging characteristics, humidity and heat resistance characteristics, safe carrying current of dual-port surge protector;
2. Surge suppression situation: In addition to the energy of the system working voltage, the surge protector also has energy from the surge voltage;
3. TOV operating state: The electrical stress of the surge protector is mainly TOV working voltage and current. This is related to grid quality, low voltage power supply and distribution systems, medium voltage distribution systems and grounding methods for distribution transformers. What this requires is the ability of the surge protector to withstand transient overvoltages, that is, the surge protector can withstand the UT specified in the standard.
Authoritative certification at home and abroad
In the end, it is also critical to select products with authoritative third-party certification (such as CE, TUV, CAS, CQC, etc.), and to select companies with technical accumulation, technical advantages, and sound solutions.
According to TUV, CE, CQC and other international certifications, the surge protector has excellent production technology and processing technology in the field of lightning protection, and can meet the application requirements under extreme conditions such as high temperature, high temperature and plateau areas, and can withstand harmonic current and overvoltage for a long time. , Surge protectors can be customized for customers in unique places.