As cities across Southeast Asia – from Jakarta and Bangkok to Manila and Ho Chi Minh City – convert overhead feeders to underground cable, utilities take on a new maintenance problem: cable insulation defects are invisible and expensive to locate after failure. Two complementary techniques manage the risk: acceptance testing of new installations with oscillating wave test sets, and ongoing monitoring of operating circuits with clamp-on sensors.
Why cables need special attention in the region
Installation conditions
Underground cable is installed through congested streets, in high groundwater areas and in tropical heat. Handling, bending and jointing errors during installation are the main source of defects in the early years of a cable’s life.
Termination stress
Cable terminations at switchgear are exposed to humidity, pollution and load cycling. Partial discharge at terminations is a leading cause of premature cable failures, and it is detectable before the termination fails.
Difficult fault location
Once a buried cable fails, locating the fault is slow and disruptive in dense urban areas. Finding defects while the cable is still in service avoids most of that cost.
Oscillating wave testing: proving new and refurbished cables
An oscillating wave test (OWTS) applies a damped AC voltage to the cable and measures PD activity under conditions close to operating stress. It is used to:
- Accept newly installed cable and joints before energisation
- Verify repairs and refurbishment before return to service
- Assess aged cable sections to decide whether to replace or continue operation
HUWOR’s cable diagnosis systems, including oscillating wave test sets, provide the voltage source, PD measurement and analysis in one portable unit suitable for field use in tropical environments.
Online PD monitoring with HFCT on operating circuits
For circuits that must stay in service, clamp-on HFCT sensors on cable terminations and joints measure PD pulses travelling through the cable. Key advantages:
- Non-intrusive – clamps install on earth straps or cable screens without interrupting supply.
- Continuous – PD trends are recorded around the clock, catching activity that periodic tests miss.
- Localisation – sensors at both ends of a section help localise the defect between measurement points.
A practical cable asset strategy
- Acceptance – oscillating wave test on new circuits and after major jointing work.
- Screening – periodic on-line PD surveys across the cable population to rank circuits by activity.
- Focused monitoring – permanent HFCT monitoring on circuits with known risk or critical feeders.
- Intervention – plan retermination or replacement based on trends, before failure.
About HUWOR
Zhuhai Huawang Technology Co., Ltd. (HUWOR) supplies oscillating wave test sets, HFCT PD sensors, online monitoring systems and the SCMP platform, serving utilities and EPC contractors in Vietnam, Indonesia, Malaysia, Thailand and the Philippines. Contact the HUWOR sales team for cable monitoring solutions.