This guide provides a summary of information on protecting various types of electrical equipment, with a primary focus on the application of protective relays for power transformer protection. It emphasizes the most common protection schemes and transformer types, highlighting fundamental principles rather than detailed setting procedures, which are discussed only in general terms.
Electrical engineers must weigh the cost of implementing a specific protection scheme against the risks of relying on alternative protection or potentially sacrificing the transformer. Prolonged faults can cause severe transformer damage, increase the risk of tank rupture, and lead to oil fires, posing significant safety hazards. There is no strict rule dictating the appropriate protection scheme for a given transformer. While protection schemes are sometimes linked to a transformer's MVA rating and primary voltage, many other factors must also be considered.
Factors to consider in transformer protection include:
- Personnel Safety: The severity of safety risks and whether a specific protection scheme can help mitigate these hazards.
- Structural and Process Risks: The potential danger to nearby structures and industrial processes in the event of a catastrophic transformer failure, and whether a protection scheme can reduce this risk.
- Economic Impact: A comprehensive assessment of the financial consequences of transformer failure and possible risk mitigation measures, including:
- The direct costs of repairing or replacing the transformer.
- Indirect costs due to production downtime.
- The time required for repairs versus full replacement.
- The availability and cost of backup power sources or emergency replacement transformers.
- The extent to which a protection scheme can minimize damage, shorten repair time, or convert a full replacement scenario into a repairable situation.
The complete Transformer Protection Application Guide can be downloaded in link below.
