Digital Burn-Through Bridge XHSC-60Q | 60 kV Burn Mode, 750 mA Bridge Mode, ±(0.1%·L+1 m) Accuracy

The XHSC-60Q digital burn-through bridge combines a 60 kV burn-through source and an intelligent digital bridge in one unit. It burns a high-resistance cable fault down to a low-resistance fault at up to 400 mA, then measures the fault position with the bridge at up to 750 mA — with a stated location accuracy of ±(0.1%·L+1) m over a test range of 1–50000 m.

It is intended for insulation fault pre-location in high-voltage, large-cross-section and long cable systems, including complex high-voltage cable routes with GIS terminations and cross-bonded sections — where the fault can be located without dismantling the GIS switch and without short-circuiting the cross-bonding links.

• Fully automatic testing with one-key operation.
• Automatic diagnosis of the cable fault type, with guidance to the next step.
• Automatic check of the wiring, together with protective earth grounding detection.
• Automatic data storage, for review of historical test data.
• Digital power control, for a more stable output voltage and current.
• Wide-range voltage input, with automatic discharge of the specimen under test.
• Pull-rod chassis on castors: light, and easy to move and carry.
• No blind zone compared with the wave-reflection method — suited to short cables and to faults close to the cable end.
• High output voltage and high current, suited to insulation fault pre-location on long, large-cross-section high-voltage cable systems.

The burn-through mode reduces a high-resistance fault to a low-resistance fault so that it can be measured; the bridge mode then measures the fault position. The intelligent diagnosis mode is used to establish the fault type before either mode is applied.

The equipment delivers up to 60 kV. At least two people must be present: one makes the connections, the other checks them before the test starts. The protective earth terminal is the safety earth for the enclosure and must be reliably earthed with the dedicated earth lead — clamped to a test bay earth pillar, an electrical cabinet earth bar or a machine base.

For capacitive specimens such as cables, do not short the high-voltage output clamps to earth while residual voltage remains on the cable; although the instrument supply is off, the clamps are still connected to the cable, and the pulse energy of a direct discharge can feed back through the output cable and damage the instrument. If the residual voltage falls too slowly, wait until it has dropped, then discharge through a resistor. If the instrument behaves abnormally, press the high-voltage disconnect / emergency stop button at once. In rain or at high humidity, keep the output voltage lower, and avoid long periods of high-output operation. When the screen indicates that discharge is complete or the test has ended, switch off the supply, discharge the specimen with the discharge rod, fit the earth lead, and have a second person confirm before disconnecting.

If a bridge reading is in doubt, the supplied bridge test box can be used to verify it. With the red and black clamps and the earth connected as marked, the box provides two test lines: on the low-sensitivity line the bridge should read 33.3%, and on the high-sensitivity line the reading should match the value shown on the test box panel. If there is no significant deviation, the bridge is within specification.

1. What is the difference between burn-through mode and bridge mode?

Burn-through mode applies up to 60 kV DC at up to 400 mA to convert a high-resistance fault into a low-resistance fault. Bridge mode then works at 0–4 kV DC, bipolar, at up to 750 mA to measure the fault position. The diagnosis mode (30 mA at 0–60 kV DC) is used first to establish the fault type.

2. What accuracy and range can be expected?

Location accuracy is ±(0.1%·L+1) m, with a test range of 1–50000 m.

3. Can a fault be located without dismantling the GIS switch or the cross-bonding links?

Yes. The equipment is intended for insulation fault pre-location in complex high-voltage cable systems with GIS terminations and cross-bonded sections, and the fault can be located without dismantling the GIS switch and without short-circuiting the cross interconnections.

4. Why use the bridge method instead of a travelling-wave method?

The bridge method has no blind zone, so it is particularly suited to short cables and to faults near the cable end — cases where a wave-reflection measurement is limited by its blind zone.

5. What supply and site conditions does it need?

100–240 V, 50/60 Hz, with a maximum power of 2 kVA. Operating range is −10 °C to +55 °C at humidity up to 90%; the enclosure is IP54 and the unit weighs 22 kg excluding accessories, on a pull-rod chassis with castors.

Tell us the cable voltage class, cross-section and route length, whether the terminations are GIS, and whether the route is cross-bonded — and we will confirm the working mode sequence for your fault.