The reliability of the electric power system depends, in part, on the proper operation of the protective relay systems. The proper operation of any relaying scheme, in turn, relies on the proper voltage and current signals applied to it.

Addelec Power Services uses the CPC100 for CT Testing which is designed to meet the highest standards for performing excitation, ratio, polarity and winding resistance tests on current transformers (CTs) as well as burden-impedance measurement.

The CPC 100 can generate up to 2000 A AC with CP CB2 current booster for injecting into the CT‘s primary side and testing its ratio, polarity and burden. For excitation curve measurement, the CPC 100‘s output is connected to the secondary terminals of the core. Within an automatic test run, the CPC 100 measures the excitation curve and displays the knee point voltage and knee point current (according to the relevant IEC or IEEE / ANSI standard). The CPC 100 also automatically demagnetises the CT core after the test. Using the winding resistance measurement function also allows the user to calculate the accuracy limiting factor (ALF) for protection circuits and the instrument security factor (FS.)

Routine Testing is required to verify correct operation.

Current Transformer Testing

  • CT ratio (with burden) up to 800 A or 2000 A with CP CB2, 5 kVA output power
  • CT burden up to 6 A AC | secondary
  • CT excitation curve (knee point) up to 2 kV AC
  • CT Polarity check with CPOL up to 800 A or up to 2000 A with CP CB2, 5 kVA output power
  • Accuracy limiting factor (ALF) test
  • CT ratio with voltage up to 130 V AC | bushing CTs
  • CT winding resistance up to 6 A DC
  • CT voltage withstand test up to 2 kV AC
  • CT ratio Rogowski and CT ratio low power up to 800 A or up to 2000 A with CP CB2, 5 kVA output power

Testing is required to identify equipment failures and degradation in service, so that corrective action can be taken.