Case Study: Fukuoka Substation Cable Fault Location In December 2024, a 35kV XLPE cable at a substation in Fukuoka, Japan experienced an intermittent fault causing repeated circuit breaker trips. Our team deployed the HP Portable Extended System to locate and resolve the issue. The Challenge The fault was intermittent - appearing only under load conditions - making standard TDR testing ineffective. The cable ran 3.2km through a mix of direct burial and duct sections, with several joint points along the route. Our Approach We used the multi-pulse method (MIM) with the A30D multi-pulse generator at 32kV. The differential waveform analysis revealed a reflection at approximately 1,850m from the test point. ICE testing confirmed the fault location. Precision Pinpointing The C11 acoustic-magnetic pinpointer was deployed at the pre-located position. Using BNR smart noise reduction (the surrounding area had significant traffic noise), the team pinpointed the fault to within 0.2m using acoustic-magnetic time difference measurement. Result The fault was found at a joint where moisture had penetrated through a damaged outer sheath. Total time from arrival to fault confirmation: 4 hours. The customer avoided an estimated $12,000 in alternative fault location costs and 2 additional days of outage.
