The field problem
Misapplication of High-Risk Substation Grounding Criteria
project / problem
22 kV medium-voltage substation within a renewable-energy project for TSK. The designer adopted a grounding philosophy and Step/Touch Voltage assessment approach associated with a different risk context, applying requirements mechanically without first evaluating the system, voltage level and operating conditions.
pis engineering review
PIS emphasized that selecting a code is not sufficient by itself. The engineer must first establish the scope of application, then determine which provisions apply to the actual project. A design philosophy should not be transferred from one project to another without an engineering applicability review.
Why it failed
PIS Engineering Review
PIS emphasized that selecting a code is not sufficient by itself. The engineer must first establish the scope of application, then determine which provisions apply to the actual project. A design philosophy should not be transferred from one project to another without an engineering applicability review.
Corrective Recommendation
Reassess the Step and Touch Voltage risk-evaluation methodology against the actual characteristics of the 22 kV station and the project requirements, rather than applying every criterion automatically.
WRONG vs CORRECT
WRONG - Treat the title of a recognized standard as proof that every provision and design philosophy applies identically to every substation.
CORRECT - Establish scope, system characteristics, hazards and governing project requirements, then apply the relevant provisions with documented engineering judgement.
Follow the engineering
Switch between the field condition and the engineering concept. Trace the path and examine what changes.
Inspect the engineering detail
What changes
Establish scope, system characteristics, hazards and governing project requirements, then apply the relevant provisions with documented engineering judgement.
Correction & verification
Reassess the Step and Touch Voltage risk-evaluation methodology against the actual characteristics of the 22 kV station and the project requirements, rather than applying every criterion automatically.
Verification recorded in the case
- Record as-built topology and connection points.
- Repeat the measurement or functional test under a defined condition.
- Confirm continuity and mechanical integrity of the corrected path.
- Document instrument/setup, environmental condition and test method.
- Close the case only when evidence supports the conclusion.
References & project context
References are reproduced from the PIS casebook. Select the governing edition and project acceptance criteria before using them for a design. The diagrams explain the concept, rather than define construction dimensions.
Apply the contract-specified IEC/IEEE/NFPA/local framework relevant to the actual project scope. Verify exact editions and clauses before external publication.
PIS reviewed field handbook · PIS-CS-033
The engineering lesson
Using the correct standard incorrectly can be as problematic as using the wrong standard.
Engineering judgement determines which requirements are applicable - not the title of the standard alone.
Take the lesson into your next design review.