Substation safety rules every operator must know
Clear safety and switching procedures are essential for preventing accidents and ensuring reliable operations in substations and on the grid.
Image for illustrative purposes
Safety in substations relies on strict compliance with switching rules, isolation procedures, and the use of barriers, locks, and tags. Switching operators, authorised by utilities, are responsible for tasks ranging from field switching of non-SCADA apparatus to issuing permits, setting up safe working zones, and disabling automatic equipment.
Central to safe operations are tagging and lockout procedures. Tags serve as visible warnings to prevent accidental energisation of equipment. The most common include:
- Danger–Do Not Operate: used at isolation points to prevent inadvertent operation.
- Caution–Vicinity Work in Progress: indicates work under way near protection equipment.
- Danger–Restricted Use: applied under a Sanction to Test permit, allowing controlled operation.
- Warning–Out of Service: attached to equipment not ready for use, removed only when safe.
Locks are applied under a Lock Out Tag Out (LOTO) procedure, often using both control and personal locks, to ensure a safe working environment.
Switching programmes also require operators to follow precise steps. For example, proving equipment de-energised involves testing instruments before and after use to confirm validity. When applying portable earths, operators must inspect leads, connect securely to earth points, and ensure clamps are tight.
Common hazards in switching environments include electric shock, arc flash and blast, toxic fumes, and step or touch potentials. Operators must also carry out pre- and post-switching checks, looking for signs of faults such as unusual smells, sounds, or visual damage.
Adhering to these safety and switching rules protects not only the operator but also colleagues, equipment, and the stability of the wider network.
Source: EEP
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