IEC EN 60076-3 Power Transformers - Part 3: Insulation Levels - Standard Test for Dielectric Tests and External Voids in Air

EUROLAB, with its state-of-the-art accredited laboratories and expert team, provides precise and fast testing services within the scope of IEC EN 60076-3 testing. It gives the insulation requirements for power transformers and the corresponding insulation tests for certain windings. It applies to single-phase and three-phase oil-immersed power transformers as defined in IEC EN 60076-1.

For power transformers and reactor categories with their own IEC standards, this standard applies only to the extent that it is specifically called by cross-reference in other standards.

Insulation levels and dielectric tests specified in this standard are valid for internal insulation only. While it is reasonable to reference the rated withstand voltage values ​​specified for the internal insulation of the transformer for its external insulation as well, this may not be true in all cases.

Failure of the non-self-healing internal insulation is catastrophic and would normally result in prolonged outage of the transformer, whereas an external flashover can involve only a brief interruption of service without permanent damage. Therefore, for greater safety, higher test voltages may be specified by the buyer for the internal insulation of the transformer than for the external insulation of other components in the system. When such a distinction is made, the outer spaces must be adjusted to fully meet the internal insulation test requirements.

In terms of all factors that may affect the dielectric strength of the transformer, the transformer will be installed exactly as it is in service. Normally it is assumed that during tests no insulating liquid or gas is circulated and chillers do not need to be installed. Any equipment designed to collect or detect free gas resulting from defects in insulation should be installed and monitored during testing. If free gas is detected during any test, the nature and cause of the gas will be investigated and any further action will be agreed between the purchaser and the manufacturer.

EUROLAB assists manufacturers with IEC EN 60076-3 test compliance. Our test experts, with their professional working mission and principles, provide you, our manufacturers and suppliers, the best service and controlled testing process in our laboratories. Thanks to these services, businesses receive more effective, high-performance and quality testing services and provide safe, fast and uninterrupted service to their customers.