Question

Company A is a high voltage equipment manufacturer. They produced high voltage
transformers rated 300 kV and above. All high voltage tests such as AC, DC and
impulse have been conducted to the equipment. However, they have been
penalized due to non-compliance issue. Justify the root cause of this problem and
support with relevant facts.

Answer 1

The main reason for non-compliance are overheating and construction,the construction and tests for the transformers must comply with the relevant equipment or  transformer standards EN/IEC 60742 actually.The transformers that comply with this standard EN 60742 usually are in compliance with the transformer requirements contained in the equipment standards. These standards follows strict construction and testing requirements and those are the benchmarks that every manufacturer should follow to avoid non complance issue and to maintain quality and safety. Some doesn't follow and they will get penalised when testing for compliance by the authorities.One of the requirement of the standard is that the transformers must be protected against overheating during short circuit and over load conditions, these standards limit the allowed temperature rise in normal as well as internal or external faults.This is just one example of the standard requirement.

Some of the common issues for non compliance of transformers include

• Improper wire terminations.
• Loose parts bridging from primary to secondary,
• Low quality or Improper class of insulation.
• Secondary fusing missing.
• Displacement of windings.
• Inadequate creepage or clearance from primary to secondary.

Some other facts are protective devices are mandatory in some cases to ensure efficient protection against overloading and short circuits to have compliance with the standards