Our transformer maintenance services team were contacted by an Asset Manager at a large Queensland sugarcane refinery after they reviewed their most recent transformer insulating oil analysis report. Results indicated occurrence of a serious T3 Thermal Fault – high temperature heating (> 700°C). Typically, these faults include large circulating currents in the tank and core, loose connections in the HV winding circuit, and misalignment of contacts in de-energised tap changers.
The request was to further review the test data provided by the Asset Manager, to offer an independent engineering opinion and to help pinpoint the cause of the problem. Recommendations for further investigation and management of the asset were also sought.
Resulting recommendations included regular DGA testing to monitor the fault and electrical testing to investigate the cause of the DGA gassing problem. Further recommendations also included an internal inspection / videoscope to identify burnt / misaligned contacts in the DETC (off load tap changer). Acetylene generation in the transformer pointed to either the severity of the fault or the involvement of electrical contacts.
On receipt of Ampcontrol’s recommendations, the Asset Manager conducted an internal investigation on the transformer. The source of the fault was identified as a contact in the DETC.
Read the full case study here.
Now offering remote transformer condition auditing and diagnostic support, our team can review third party oil analysis reports and provide technical expertise to diagnose issues while providing repair plans to ensure continuity of services when access to site can be challenging. Contact us for more information on how to access these services at your site.