Fault Current Limiter

Fault Current Limiter


The Thycon Fault Current Limiter introduces a new dimension to system protection and power quality. Unlike existing PTC and superconducting limiters, it is easy to install, requires virtually no maintenance and is low cost by nature and unlike electronic limiters or breakers, it requires no control electronics and is fail-safe. Being self-acting and self-resetting, it is suitable for remote and isolated installations.

The TFCL is easily retro-fitted to existing networks where these are to be given additional capacity. It requires no separate power supply nor feed-back links, no air-conditioning, no power-factor compensation or other correction techniques and does not perturb normal network operation with harmonics or voltage sags. It produces no arcs and is safe to use in explosive atmospheres. Being passive, it produces no EMI (electromagnetic interference) in normal operation.

Thycon also offers TFCL solutions in new installations and undertakes fault-level co-ordination studies where the TFCL can be used to enhance the performance of conventional mechanical breakers.

Operation of the TFCL
Under normal conditions, the TFCL allows the load current to pass from the supply to the load unhindered. Under fault current conditions, when the AC current increases in magnitude beyond full load conditions, the FCL begins to act as a high impedance such that the peak asymmetric pulse is completely eliminated and the steady-state RMS current value is below the prospective RMS value.

The TFCL allows design flexibility and can be adapted to meet different application requirements. In particular, the initial peak current, the steady state current, as well as the time taken to reach these two values, are design variables.

Benefits of the TFCL

  • Elimination of the peak asymmetric fault current, similar to Solid State Breakers
  • Fast response of SSB but at much lower cost
  • Limitation of let-through energy (similar to fuse)
  • Self-limiting: no detection or control circuitry required
  • System is based only on passive and non-active components
  • Suitable for both LV and MV as well as single or three phase networks
  • Protection can be co-ordinated with existing or supplemental breakers
  • Optional ‘‘self test’’ functionality

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