Despite the fact that the protective device using spark gaps can withstand high overload currents, this technology has some significant drawbacks. To trigger the device, the high value of the transmitted voltage (kV), which results in damage to the equipment being protected. The intensity of the spark occurring at the time conducting state, often causes interference and leads to a malfunction of nearby electrical equipment. Residual currents lead to disruptions in power and, therefore, unpredictable in the equipment. – Parallel connection of varistors.
These protective devices used by several varistors based on metal oxide, connected in parallel to obtain high current values overload. These varistors have low thermal stability and are easily damaged due to thermal wear. Electrical characteristics of varistors connected in parallel are not identical, which also reduces their life service. Such devices are designed to use an internal fuse, tripping a safety device with strong momentum in order to avoid ignition and explosion. – Combining the spark gaps and varistors. To improve overlooked voltage spark gaps, some manufacturers use spark gaps and varistors with a trigger circuit. Although nominally these devices can withstand stronger pulses, laboratory testing and field trials have shown that difficulties arise in connection with different temporal response characteristics of surge arresters and varistors. Several years ago, was created new concept of protective devices – surge suppression module Strikesorb.
These devices successfully withstand large current overload, repeated lightning and thunder, pulse voltage, with This performance of the devices remain unchanged for several years. The module includes a heavy duty drive (varistor), made on the basis of metal oxide (PTO) that is mounted under pressure in a sealed aluminum casing.