Line Test

DC High Speed Circuit Breakers (HSCB) are valuable components which must be protected against wear and tear and excessive current flow. Before closing a DC High Speed Circuit Breaker in a power line it is therefore advisable to test whether a short circuit is occurring by means of line test resistors. The resistor is electrically connected through a contactor - if no fault current is detected - then it is safe to activate and close the HSCB If a fault current is detected then, there is a fault somewhere on the line. It is as well possible that activating the resistor a few times in a row (On - Off cycles with the desired number of consecutive ON steps) may help in eliminating the physical cause of the short circuit.

The essential parameters needed to design a Line Test Resistor are:

  • Nominal Voltage
  • Test Current
  • Duty cicle