Cable Water Terminations & Heat-Cycle Test Systems
Terminates and load-cycles HV cable for type and qualification testing
You cannot type-test a 500 kV cable without terminating it, and no dry termination holds that stress in a test bay without becoming the weakest point in the circuit. A water termination grades the field along a column of conditioned water, which is why it is the standard laboratory answer for AC withstand, impulse, tan δ, partial discharge and breakdown testing on extruded cable.
Terminations cover 150 kV to 800 kV RMS on AC and 550 kV to 1,800 kV negative polarity on impulse, with partial discharge below 1 pC from 150 to 300 kV and below 2 pC from 400 to 800 kV at rated voltage. Cable diameter is accepted to 133 mm including insulation, extending to 160 mm at 700 kV and 180 mm at 800 kV. The water conditioning unit supplies 60 or 120 kW of cooling from a 500 L capacity, holding water to 60 °C maximum at 4 atm maximum pressure, conductivity between 0.1 and 2 µS/cm, resistivity above 2 MΩ·cm and minimum flow of 45 L/min. Temperature, pressure, flow and conductivity sensors run on 4–20 mA loops into a programmable processor with panel display, low-level interlock and emergency stop.
Why it matters
Partial discharge below 1 pC on the termination means the number your detector reports belongs to the cable, not to the setup.
Conductivity held between 0.1 and 2 µS/cm keeps the water resistive enough to grade the field and consistent enough to do it the same way every time.
Acceptance to 133 mm, and 180 mm at 800 kV, covers EHV and heavy submarine constructions without a custom termination.
Heat-cycle current steps from 7.5 A to 240 A with a 1,500 VA to 100 kVA heating transformer cover accessory samples and full test loops from one system.
Low-level interlock and emergency stop are built into the conditioning unit, so a long load cycle is supervised by the system rather than by an operator watching a gauge.
Ratings
Water termination — AC voltage: 150 kV to 800 kV RMS
Water termination — impulse: 550 kV to 1,800 kV negative polarity
Water termination — PD at rated voltage: <1 pC (150–300 kV) and <2 pC (400–800 kV)
Water termination — cable diameter: Up to 133 mm (160 mm at 700 kV, 180 mm at 800 kV) including insulation
Water conditioning unit: 60 or 120 kW cooling, 500 L capacity, 60 °C maximum water temperature, 4 atm maximum pressure, conductivity 0.1–2 µS/cm, resistivity >2 MΩ·cm, minimum flow 45 L/min
Instrumentation: Temperature, pressure, flow and conductivity sensors on 4–20 mA loops with programmable processor, panel display, low-level interlock and emergency stop
Heat cycle — heating transformer: 1,500 VA to 100 kVA
Heat cycle — current steps: 7.5, 15, 20, 30, 40, 50, 60, 70, 80, 100, 120, 240 A
Heat cycle — control: Temperature control and current control; safety interlock; mobile carts
Standards
IEEE 404
IEC 60840
IEC 62067
IEC 60060-1
IEC 60270
Applications
Extruded HV cable type, qualification and delivery testing
PD, AC withstand, impulse, tan δ and breakdown testing on cable
Load-cycle testing of cable and switchgear cabinets
Cable factory test bays
Questions engineers ask
Why use a water termination rather than a dry one? A water termination grades the electric field along a column of conditioned water instead of through a solid stress cone, so it holds 800 kV RMS and 1,800 kV impulse with partial discharge below 1 pC at the lower ratings. It also accepts any cable diameter inside its range, which a moulded dry termination cannot.
What does the heat-cycle system add? IEC 60840 and IEC 62067 qualification requires load cycling, not voltage alone. The heating transformer runs from 1,500 VA to 100 kVA with current steps of 7.5, 15, 20, 30, 40, 50, 60, 70, 80, 100, 120 and 240 A, under temperature or current control, with safety interlock and mobile carts so the loop is built around the sample.
