60kV Intelligent Burn-Through Bridge Cable Fault Locator 750mA Digital Bridge HV

The XHSC-60Q Intelligent Burn-Through Bridge combines a burn-through unit and an intelligent bridge in one instrument. In burn-through mode it provides a rated voltage of 60kV and a maximum arc current of 400mA, and can quickly burn a high-resistance fault into a low-resistance fault. The digital bridge provides a maximum test current of 750mA, greatly improving fault locating accuracy. It is especially suitable for the insulation fault pre-location of high-voltage, large cross-section and long-length complex cable systems — for example, complex high-voltage cables with GIS terminations and cross-bonding — so that pre-location can be completed quickly without removing the GIS switchgear or short-circuiting the cross-bonding.

The XHSC-60Q is positioned for insulation fault pre-location on high-voltage, large cross-section and long-length complex cable systems, and in particular for high-voltage cables with GIS terminations and cross-bonding links. It is engineered for utility high-voltage cable maintenance and fault-repair crews who must pre-locate faults on cross-bonded high-voltage cable sections without dismantling GIS switchgear or opening the cross-bonding, for EPC and testing contractors carrying out pre-location on long, thick high-voltage feeders, and for cable-operation teams that need both fault burning-through and digital bridge measurement from a single instrument. Unlike the other instruments in the same category, which rely mainly on the wave reflection method, have a blind zone and are aimed at shorter, simpler cables, this instrument uses the bridge method with no blind zone — making it especially suitable for short cables and for fault points close to the cable end, as well as for long, complex high-voltage cable systems.

The instrument is organized around four working modes, selected according to the fault type and the cable data available:

An intelligent diagnosis test effectively evaluates the insulation state of the cable under test. From the breakdown voltage or fault impedance value in the test result, it is easy to judge the cable fault type, and therefore to decide whether a burn-through test is required or whether bridge or section measuring mode can be entered. When locating with the bridge mode or section mode, if the current is less than 20mA or unstable, the test should be terminated and the burn-through function used to burn the high-resistance fault into a low-resistance fault; once the current is stable, the fault pre-location measurement can be carried out.

In burn-through mode a suitable burn-through voltage is set — if an intelligent diagnosis test has been performed in advance, the set voltage should be slightly higher than the intelligent-diagnosis breakdown voltage. A maximum burn-through time is also set, up to a maximum of 90 minutes. When the intelligent burn-through function is enabled, the burn-through test ends automatically once the fault impedance value drops to the value required by the measuring mode; when it is not enabled, the burn-through test ends automatically when the set time is reached. (Whether the intelligent burn-through function is enabled can be set in the settings menu.)

In bridge mode the cable length is entered (range 0–50km) and the test current is set; the fault distance and percentage are shown on the screen. In section mode the cable material, cross-section and test current are set; the fault distance is shown on the screen. For both modes the output voltage and current relationship is: within 20–75mA the output voltage is 4000V; within 80–400mA the output voltage satisfies voltage (V) × current (mA) = 300W; within 410–750mA the output voltage is 400V.

It combines a burn-through unit and an intelligent bridge in one instrument. Burn-through mode has a rated voltage of 60kV and a maximum arc current of 400mA to quickly burn a high-resistance fault into a low-resistance fault, while the digital bridge provides a maximum test current of 750mA for higher fault locating accuracy.

It is especially suitable for the insulation fault pre-location of high-voltage, large cross-section and long-length complex cable systems — for example, complex high-voltage cables with GIS terminations and cross-bonding — and can complete pre-location without removing the GIS switchgear or short-circuiting the cross-bonding.

Use bridge mode when the cable length is known and the auxiliary phase has the same cross-section, material and length as the faulted phase; use section mode when the cross-section and material are known, in which case the auxiliary can be any core. Both modes require no broken core and a low-resistance short line at the far end.

Terminate the test and use the burn-through function to burn the high-resistance fault into a low-resistance fault; after the current becomes stable, carry out the fault pre-location measurement again.

A maximum burn-through time can be set, up to a maximum of 90 minutes. When the intelligent burn-through function is enabled, the test ends automatically once the fault impedance value drops to the value required by the measuring mode; when it is not enabled, the test ends automatically when the set time is reached.