-
Why do signal SPDs commonly use gas discharge tubes instead of varistors as the core primary energy dissipation element?
Mar 06 , 2026
The fundamental reason for choosing gas discharge tubes (GDTs) as the primary surge protection component in signal lines is the need to prioritize the integrity of signal transmission while simultaneously providing effective surge protection. This choice is based on the superior characteristics of GDTs in terms of parasitic capacitance, balance maintenance, and tolerance to high currents, which ar...
Read More
-
Now SPD monitoring has gone far beyond simple "on/off" indications. What intelligent directions is it developing towards?
Mar 12 , 2026
Traditional SPD monitoring only provides a dry contact signal based on a mechanical disconnector, which is a typical "post-failure alarm"—it informs the user that the SPD has completely failed and needs to be replaced. Modern intelligent monitoring modules, however, utilize built-in microprocessors and sensors to transform the SPD from a passive protection component into an intelligent node capabl...
Read More
-
What is the formation mechanism of the "ground potential rise"? How it cause damage to electrical and electronic equipment inside and outside the building?
Mar 19 , 2026
Ground potential rise is caused by transient high potentials resulting from lightning current entering the ground. When lightning strikes a building's lightning rod or the nearby ground, thousands to hundreds of thousands of amperes of lightning current are discharged through the grounding system. Due to the resistance and inductance of the grounding system, according to U=IR+L·di/dt, the potentia...
Read More
-
What are the main types of coaxial signal SPDs? What are the differences in their working principles, technical characteristics, and application scenarios?
Apr 09 , 2026
Coaxial SPDs can be mainly classified into gas discharge tube, semiconductor voltage limiting, DC isolation, and quarter-wavelength technologies based on their technical principles. Among these, gas discharge tube and semiconductor voltage limiting types form the core of basic protection, while DC isolation and quarter-wavelength technologies are key designs for achieving specific functions. 1. Ga...
Read More
-
For SPDs used in high-altitude areas, the electrical clearance needs to be increased. How does the GB/T 18802.11 standard reflect this requirement in testing and certification?
Apr 28 , 2026
The GB/T 18802.11 standard explicitly acknowledges the influence of altitude on electrical clearance insulation strength and incorporates this through an "altitude correction factor" in the testing conditions. The standard typically uses 2000 meters as the baseline altitude. For surge protective devices (SPDs) claimed to operate normally at higher altitudes (such as 5000 meters), the testing requi...
Read More
-
What is "ground potential rise" phenomenon? How it cause damage to electrical and electronic equipment inside and outside the building?
Jun 01 , 2026
Ground potential rise is caused by transient high potentials resulting from lightning current entering the ground. When lightning strikes a building's lightning rod or the nearby ground, thousands to hundreds of thousands of amperes of lightning current are discharged through the grounding system. Due to the resistance and inductance of the grounding system, according to U=IR+L·di/dt, the potentia...
Read More
-
How is the Up value determined in an SPD with multiple protection modes (such as L-N, L-PE, N-PE)? What is the important guiding significance of SPD selection
Jun 26 , 2026
According to the standard, the declared Up value of a multi-mode SPD is the maximum residual voltage value measured across all its protection modes. For example, for a three-phase SPD, if the residual voltage is 1.5 kV in L-PE mode, 1.8 kV in L-N mode, and 2.0 kV in N-PE mode, then the Up value of this SPD should be specified as 2.0 kV. This means that the protection level provided by this SPD to ...
Read More