A Transient Voltage Surge Suppressor (TVSS) or Surge Protection Device (SPD), as they are also called, is a device that accomplishes two basic functions.
It provides a place for a rise in current and voltage to equalize (other than across your equipment) load. The object is to do all of this as quickly and effectively as possible, to be reliable enough to be ready when the next transient event occurs whether it be in 10 nano-seconds or 10 cycles and, to be able to repeat this performance over hundreds of thousands of events without failure.
How Does Surge Suppression Work?
The major design goal is to divert as much of the transient energy away from the load as possible by providing a lower impedance path and then to address the effects of the surge with the components of the SPD. Various types of surge suppression components are used to provide this low impedance pathway, depending on the specific application of the device.
The most common component found in AC voltage devices is the Metal Oxide Varistor (MOV). Under normal conditions the MOV presents itself as a high impedance element. However, when the voltage level rises to a level exceeding the threshold of the MOV, the resistance of the MOV drops rapidly (within nanoseconds) providing a low impedance path of flow. The MOV has become the component of choice in AC power applications (over 95% of AC SPD’s use MOV’s) because of its high energy handling capability and reliable clamping performance.
To enhance the performance of the tried and true MOV, we incorporate other components in our SPD’s. This Hybrid Network approach to TVSS design allows our devices to have faster reaction time as well as a longer life expectancy.
Also, due to the lower magnitude of transient energy, the devices used for protection of computer data lines and telephone communication equipment contain components that vary drastically from those found in AC power devices. The goal is the same however, to provide effective/reliable protection as fast as possible and as many times as necessary to assure the survival of the protected equipment.
Who Needs Transient Voltage Surge Protection?
Everyone who uses electricity (grid supplied or locally generated), telephone lines (voice only or fax/modem/data), computer data lines (data collection, data transmission, computer communication) needs some type of Transient Voltage Surge Suppression (TVSS).
In short, anyone who uses wire to accomplish any of these functions is in need of effective/reliable surge suppression.