IEEE Std C37.10-2011 pdf download – IEEE Guide for Investigation, Analysis, and Reporting of Power Circuit Breaker Failures.
3. Definitions For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary: Glossary of Terms & Definitions should be referenced for terms not defined in this clause. 4 Report writers are encouraged to use the following definitions to promote consistent language in the report and to assist understanding by those reading the report. 3.1 ancillary equipment: Auxiliary or accessory equipment (e.g., thermometer, liquid level gauge, pressure gauge) (see also The IEEE Standards Dictionary: Glossary of Terms & Definitions). 3.2 circuit breaker unavailability: Time from the discovery of the failure until the breaker is ready to be returned to service. 3.3 contributing cause: A condition that contributes to the cause of the failure; however, may not of itself, result in failure. 3.4 control circuit failure: Failure attributed to the inability of the electrical control circuit to perform its function. 3.5 defect: Imperfection in the state of an item (or inherent weakness) which can result in one or more failures of the item itself or of another item under the specific service or environmental or maintenance conditions for a stated period of time.
3.10 failure analysis: The logical, systematic examination of an item or its diagram(s) to identify and analyze the probability, causes, and consequences of potential and real failure. (See The IEEE Standards Dictionary: Glossary of Terms & Definitions.) 3.11 failure cause: The circumstances during design, manufacture, or use that have led to failure. Synonym: root cause. (See The IEEE Standards Dictionary: Glossary of Terms & Definitions.) 3.12 failure detection: Examination to determine the position, evidence, and type of failure. 3.13 failure mode: The manner in which failure occurs; generally categorized as electrical, mechanical, thermal, and contamination. 3.14 failure modes and effects analysis (FMEA): A process of identifying potential failures and their corresponding effects on the product or process under consideration—generally a design tool; however, it can also be used for failure analysis. 3.15 focused tests: Tests performed to identify a particular area of failure. 3.16 forensic engineering: Forensic engineering is the investigation of materials, products, structures or components that fail or do not operate or function as intended, causing personal injury or damage to property. 3.17 initiating cause: A cause that directly leads to the failure. 3.18 in-service inspection: Investigation of the principal features of the circuit breaker in service, without dismantling. This investigation is generally directed toward pressures and/or levels of fluids, tightness, position of relays, pollution of insulating parts; however, actions such as lubricating, cleaning, washing, etc., that can be carried out with the circuit breaker in service are included. NOTE—The observations resulting from inspection can lead to the decision of carrying out overhaul.