Surge protection device for suppression of continuous pulse

Abstract

The invention relates to a surge protection device SPD for suppression of continuous pulses, which is a technical improvement of a SPD formed by serial connection of a gas discharge device, such as a gas discharge tube, an air gap and the like, and a voltage-limiting component, such as a piezoresistor, a surge suppression diode and the like. In the improved technical scheme, a discharge resistor RX is connected with the voltage-limiting component in parallel, thereby ensuring the residual voltage stability of the overall SPD under the continuous pulse current and protecting the electronic and electrical equipment.

Description

technical field [0001] The present invention relates to a surge protector, especially a surge protector used to suppress surge overvoltage to protect electronic and electrical equipment, and the residual voltage of the surge protector under continuous pulse current is relatively stable . Background technique [0002] Surge protective device (SPD) is a kind of component with nonlinear characteristic of volt-ampere as the main functional component, which is used to suppress instantaneous overvoltage and discharge surge current. It is widely used in various electronic and electrical products. . Typical components of voltage limiting characteristics are piezoresistors and semiconductor surge suppression diodes, typical components of switching characteristics are gas discharge tubes, air discharge gaps, thyristor diodes, etc. SPDs using only piezoresistors (MOV) or SPDs using only gas discharge tubes (GDT), or SPDs composed of piezoresistors and gas discharge tubes in series (h...

AI Technical Summary

Problems solved by technology

[0003] However, the ordinary V-G series SPD has an important disadvantage: because the leakage current of the MOV element is extremely small at low voltage, the equivalent resistance can be as high as tens of megohms or higher, and the discharge formed by the product of this resistance and the inherent capacitance of the MOV The time constant can reach the second level. Therefore, under continuous pulse current, the charge charged into the inherent capacitance of MOV by the previous pulse current cannot be discharged quickly. When the next pulse is applied, and if this pulse is of the same polarity as the previous pulse If so, then the residual voltage on the inherent capacitance of the MOV will be superimposed on the breakdown voltage of the gas discharge element, so that the discharge voltage of the V-G series combination will increase

This seriously damages the protection performance of SPD, because the actual lightning discharge is multiple discharge, the average number of pulses is 2 to 3, and the maximum recorded is 42 pulses, and the pulse interval is roughly 0.6ms to 0.8s. Therefore, the ordinary V-G series SPD Practically unsuitable for suppressing continuous pulses

Images