IEEE Std C57.125 pdf free download
IEEE Std C57.125 pdf free download.Failure Investigation, Documentation, Analysis, and Reporting for Power Transformers and Shunt Reactors.
5.3.2.1 Electrical hazards
There are three main electrical hazards—shock, arc flash, and arc blast—to which test personnel may be exposed. particularly if the transformer is not electrically isolated following proper procedures as mentioned in 5.3.3. Other hazards may be present, and the user needs to consult applicable safety rules and regulations and take necessary precautions. Electric shock is contact with energized electrical equipment, conductors, or circuit parts that causes the flow of electrical current through the body. The severity of the shock is determined by the amount of electrical current, the total time that it flows through the body, and where it flows through the body. Humid or wet conditions or sweaty skin increase the potential for electrical shock. Consider shock hazard at any voltage greater than or equal to 50 V. Burns to the skin arc also another result of an electrical shock. Internal damage caused by the electrical current flowing through the body is also possible; if shocked. the worker should report the incident and seek medical attention.
Electrical equipment that faults and creates an arc flash can expose a worker to extreme heat causing severe burn. Some secondary hazards related to an arc flash are the following:
— Fire
Toxic smoke inhalation from vaporized copper
— Sound pressure that could damage hearing
High intensity, ultraviolet, and infared light that may damage eyesight
— Flying molten metal that may cause injury
Arc blast is associated with the release of tremendous pressures as a result of an arc fault where current flows through the air between two conductors or a conductor and ground. Vaporized copper, molten metal. pressure waves, shrapnel, intense noise, and toxic smoke/gases are some of the resultants of an arc blast. Dangers associated with an arc blast event are high pressures, sound, and shrapnel.
Users of this guide need to consult and follow fire safety rules, regulations, and other safety requirements and precautions including, but not limited to, personal protective equipment (PPE) and facility protections in connection with any testing or evaluation of the transformer equipment.
5.3.2.2 Other hazards
When working on a transformer, the following additional hazards need to be taken into account when planning the work and completing a pre-job hazard analysis:
Falling from heights: Proper harness to provide fall protection needs to considered and used in accordance with applicable safety rules, regulations, requirements and precautions.
— Confined space: Prior to entry, confirm that the atmosphere inside the tank is adequate to support life according to company guidelines and procedures. manufacturer’s instructions and applicable safety rules, regulations, requirements. and precautions.
— Outdoor and wet environments.
— Certain test procedures could result in fire; therefore, non-contaminating fire-fighting equipment needs to be available for use before beginning tests that apply dielectric stress to the transformer insulation system.
Tests being performed on the transformer while the equipment is under vacuum should only be done with low applied voltages. The dielectric strength of the system is significantly reduced under these conditions. See 5.3.6.3 for more details.IEEE Std C57.125 pdf download.
