Network Combination Test Set


The Network Combination Test Set was designed for cable testing and cable fault location purposes on demanding and challenging high end applications, for example, branched downtown network distribution feeders rated 4-35 kV, offshore windfarms, pipe-type transmission cables and many others.

Its ultra-high power components consist of a very fast high energy multi-stage capacitor thumper, a stepless high voltage burn transformer with continuously variable output, a thyratron output mode, optionally the most powerful VLF in the world for extreme-size capacitive loads, as well as optionally a separation device together with the world’s best performing radar Teleflex VX for a full set of TDR-based prelocation methods (ARM™, ARM Live Burning™, ICE/Surge Pulse, Loop-on Loop-off).

All operational modes are controlled by a clear, intuitive and convenient user interface based on HDW’s E-Tray™ philosophy – an effortless navigation with a single turn&click rotary knob and automated step-by-step workflow sequences. The operator just selects the mode and the fully automated system establishes the requested configuration by itself via motorized high voltage switches. Like all Megger products, the NCTS includes an extensive safety system, e.g. visible grounding of the high voltage output, residual voltage indication in case of power loss, HDW/SebaKMT’s F-Ohm™ monitoring circuit to check for proper and adequate grounding connections, smoke detectors, and many more! Safety always comes first: The NCTS is designed to provide the maximum safety for operator, personnel and equipment during the use of the system.


Components and Technical Data



Software-based User Interface

  • HDW‘s well-known and well-proven E-TrayTM philosophy
  • The user only needs to know what to do – not how to do it
  • Streamlined Turn & Click navigation
    • Selecting (Turn) and confirming (Click) options via single rotary knob
    • Description of the selected option below icons, and description of the next step above icons
  • Step by Step Procedures with Workflow logic
    • Ensure safety of initial system setup and during active operation
    • Initial setup of cable under test and selection of test mode
  • Reduced complexity
    • Only the necessary adjustment functions are shown for each operational mode
  • Fully automated operation
    • User only selects mode, software configures the system automatically via HV motor switch without any manual intervention
  • Flexible operation with controller unit on swivel arm


Power Burner

  • Unique transformer design with high voltage high current winding
  • No diode coupler or tap changer – Voltage and Current continuously variable over the full range
  • Power output 20 kW continuous
  • DC voltage output up to 40 kV DC, current from 500 mA to 5 A
  • For example:
    • 40 kV          0.5 A
    • 20 kV          1 A
    • 10 kV          2 A
    • 5 kV           4 A
    • 4 kV           5 A
    • 1 kV           5 A
    • 500 V         5 A
    • 250 V         5 A



  • Pulsed burning with high current and long current flow time
  • Significantly improved pinpointing of faults in branched networks due to increased galvanometer response when “chasing current”
  • Timing of current flow 0.5 seconds ON, 2.5 seconds OFF
  • No diode coupler or tap changer – Voltage and Current continuously variable over the full range
  • Two output modes
    • 60% duty cycle of transformer:    4 A       5…10 kV
    • 33% duty cycle of transformer:    10 A     5 kV and below


Fast recharging Surge Wave Generator (Thumper)

  • Multiple stage capacitor thumper offers optimum between energy vs. voltage
  • 3 stage design: 25 kV, 12 kV and 8 kV
  • Thumper output levels
    • 25 kV          6250 J
    • 12 kV          3600 J
    • 8 kV           3600 J
  • Re-charging to full voltage and full energy in any capacitor stage in 6 s
  • Safe discharge of 60 kJ residual charge on the cable under test


VLF AC Hipot

  • The most powerful commercially available 0.1 Hz VLF system in the world, over 20 times more test capacity at full voltage at 0.1 Hz and with 1/7th of the required input power than any available competitor’s system
  • ± 60 kV RMS Cosine Rectangular waveform, frequency fixed to 0.1 Hz
  • True Leakage Current Measurement (patented by HDW/SebaKMT)
  • Complies with all international VLF test standards (VDE, CENELEC, IEC, IEEE400) and satisfies 3x U0 on any 35 kV class cable
  • Designed for very high network feeder loads and long submarine cables
    • 25 μF @ 60 kV RMS @ 0.1 Hz – highest test capacity in the market by far
    • 31 μF @ 40 kV RMS @ 0.1 Hz
  • Superior Duty Cycle for extensive prolonged testing
    • 60 min ON, 60 min OFF for 12 times per day at full nominal load of 60 kV RMS and 25 μF
  • 60 kV DC mode with selectable positive or negative voltage output

Safety systems

The system includes extensive safety features to protect operator, equipment and surroundings during setup and active operation of the unit.

The well-established HDW/SebaKMT F-Ohm™ grounding monitoring: Continuous check of adequate system grounding, software will immediately shut HV off, and discharge and ground system if compromised

  • Redundant discharge and grounding system to dissipate maximum possible energy stored in test circuit during HV test
  • Visible ground in HV output path
  • Analog Kilovolt meter in HV output circuit for residual voltage protection in case of power loss


Available Configurations of the Network Combination Test Set

  • Combination Test Set: Fault locating module + VLF
  • Cable Fault Locating System – Fault locating module only, no VLF
  • Cable Fault Locating System PLUS – Fault locating module + TDR based prelocation
  • Cable Testing System – VLF only
  • Koopmann System – VLF + Special 60 kV High Voltage Thumper


Available Models of the Network Combination Test Set

  • Substation installation
  • Vehicle installation
  • Container version for quick transport via land, sea, and air, e.g. offshore windfarm applications



Contact Us

If you have any technical questions, or application-related questions, or if you would like to obtain a quotation, please do not hesitate to contact us.

Dr. rer. nat. Henning Oetjen  [email protected]

Dipl.-Ing. Robert Probst   [email protected]