Functions s a DC insulation and AC coupling device(decoupler), RE is used for preventing the flow of the CP current up to a predetermined voltage threshold, while passing any induced AC current. For voltage that attempts to exceed the threshold, the device instantly switches to the shorted mode, providing over-voltage protection.
This stray current is normally caused by AC fault current or lightning current and other interference. The standard threshold voltage is -2V / +2V. The threshold voltage is absolute or peak, When the voltage is switched at this scope, it is the sum of the DC and the peak AC voltage across the terminals of the device. This results in a very low ,and safe, clamping voltage across the terminals.
Applications:
1. Decouple gradient control mats (grounding mats) from pipelines.
2. Over-voltage protection of equipment from AC faults, lightning, and switching transients (e.g. insulated joints).
3. Decoupling dissimilar metals that must otherwise be AC bonded for safety.
4. AC grounding and DC isolation of electrical equipment integral to a cathodically protected system.
5. Mitigation of induced AC voltage.
Capability:
1. Blocking voltage or threshold voltage;
2. DC leakage current for a given blocking voltage;
3. AC fault current rating;
4. Lightning surge current rating;
5. Steady-state AC current rating.
