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Current Transformer Testing

The need for a comprehensive current transformer testing regime is evident when the alternative is considered: a catastrophically damaging current transformer fault.

A fault leading to an open secondary could cause the primary current to overwhelm the insulation, causing the winding to short circuit. Megger’s range of current transformer test equipment allows you to construct an in depth test and maintenance programme to prevent problems before they occur.

A routine series of diagnostics and testing for your current transformer should include CT saturation testing to identify the knee point against IEEE or IEC standards, CT ratio tests to identify that the voltage ratio is within expected parameters and current transformer resistance testing for both the transformer windings and CT insulation resistance testing.

Saturation testing for a current transformer identifies the rated knee point against IEEE or IEC standards, the point at which the transformer is no longer able to output current in proportion to its specified ratio.

Ratio tests under normal load are achieved by comparing voltage applied to the secondary winding against the resulting voltage produced on the primary winding. Current transformer resistance tests inject test voltage to measure the DC current and calculate the resistance with allowance for temperature.

Megger MVCT

CT & VT Analyser

  • Ability to test both VT and CT
  • Easy to use one-button automated test plans
  • Industry leading test duration using patented simultaneous tap measurements
  • Smallest and lightest unit on the market
  • CT Kneepoints up to 30kV
  • CT grouped testing includes Demagnetization, Knee Points, Ratios, Saturation Curves, Winding Resistances, Polarities and Phase Deviation (on all taps of multi-ratio CTs)
  • VT testing including Demagnetization, Ratio, Winding Resistance, Polarity and Phase Deviation
  • Performs Secondary Burden tests
  • Integrated 1 kV DC insulation test system
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Megger MRCT

Relay and Current Transformer Test Set

  • Industry leading test duration using patented simultaneous multi-tap measurements reduces testing time by 20% on multi-tap CTs
  • Accuracy to support testing of metering and protection class CT
  • Integrated single phase relay test system
  • Grouped testing: demagnetization, knee points, ratios, saturation curves, winding
  • resistance insulation and more
  • Measure all ratios and saturation curves on multi-tap CTs with one lead connection
  • Optional DC excitation technique for testing CTs with kneepoints up to 30 kV
  • Optional Integrated VT/CVT test system
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Megger SVERKER 900

3 Phase Relay Tester

The innovative Sverker 900 test set, which has been conceived as an engineer’s “multi-function testbox” for protection testing. It features an intuitive user interface so that a PC is not required to operate the instrument.

It centres around a touchscreen that provides access to a wide range of pre-configured virtual test instruments, allowing the required test function to be selected quickly and easily. Full manual control and configuration are also supported and, in addition to the touchscreen, the instrument is provided with a large rotary knob that can be configured as required to control the current and voltage generators.

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