Kelman Taptrans - Click to view details

On-line DGA & moisture for transformer with on-load tap changer

Dissolved Gas Analysis (DGA) of the insulating oil is recognized as the most important tests for the condition assessment of transformers. Multi-gas DGA has traditionally been confined to infrequent off-line manual sampling. As the average age of transformers globally continues to rise, the possibility of rapid ageing, unplanned outages and even catastrophic failure between off-line tests also increases, leading many asset owners to adopt on-line DGA monitoring of equipment to increase network reliability.

The Kelman™ TAPTRANS is designed for transformers with an On-Load Tap Changer (OLTC), which is recognised as one of the most vulnerable parts of the transformer and which accounts for a large portion of unplanned outages. It offers discrete multigas on-line DGA and moisture monitoring, separating the main and selector tanks from the diverter tank to avoid any risk of contamination. Utilizing photo-acoustic spectroscopy (PAS) measurement technology, well suited to field application, it provides laboratory challenging levels of precision and repeatability. Full 9 gas oil sampling and analysis can be performed as often as every hour on a single tank and up to once every three hours if all three possible oil tanks are connected.

Through close integration with GE’s powerful Perception™ software suite and/or user’s own software, historian and SCADA systems, the TAPTRANS offers full gas-in-oil trending, analysis and diagnostic capabilities including various diagnostic methods prescribed by international standards.

Key Benefits
  • Discrete measurement of all fault gases facilitates full remote diagnostic without having to go to site and take an oil sample
  • Additional DGA analysis of separate OLTC oil tank(s) enables more cost effective condition based OLTC maintenance
  • Faults can be detected in their infancy and outage scheduled when less inconvenient and less costly (normal working hours)
  • Aids condition based and predictive maintenance strategies
  • Compatible with mineral insulating oils or ester based oils (natural and synthetic


Knowledge of the condition of transformers is essential for all electrical networks and on-line monitoring of transformers is an increasingly vital component of successful asset management programs. The information provided by multi-gas on-line DGA allows valuable asset capabilities to be maximized and expensive failures to be avoided.

TAPTRANS is best suited for monitoring transformers where frequent operation of their OLTC is grid or process critical, with a view to extending asset life, preventing unexpected failure and operating on a condition based maintenance schedule.

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