What this covers
- Protection principles — which functions apply to each equipment class and voltage level, and why.
- Zone definition — overlapping protected zones with no unprotected gaps between them.
- Redundancy strategy — main and backup arrangements, duplicated supplies, and breaker failure coverage.
- Coordination criteria — grading margins, clearance time targets, and the fault cases the design must handle.
- Architecture — hardwired versus IEC 61850 station bus, and where each is appropriate for the site.
- Instrument transformer and tripping requirements — CT/VT classes, trip circuit supervision, and DC supply arrangements.
What you receive
- Protection philosophy document covering the full scope of the network
- Protection single-line diagram showing zones and device functions
- Function allocation matrix by equipment type and voltage level
- Design criteria that can be issued directly to vendors and contractors
Standards and references
Philosophy documents are written to align with IEC 60255, IEC 61850, the IEEE C37 series and IEC 61936-1, together with the client specification and applicable grid code.
Related services
Relay Logic Design
Custom protection and control logic for numerical relays, across hardwired and IEC 61850 schemes.
Relay Setting Calculations
Setting and coordination calculations that keep fault clearance selective, fast and reliable.
ATS Circuit Design
Automatic transfer schemes for critical loads — hardwired, relay-internal or PLC-based.
Need protection philosophy development scoped?
Work directly with the engineers doing the analysis — clear scoping from the first conversation.
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