Protection & Control
Design
Your protection system is only as good as its design. When relay panels are aging, documentation is missing, or you're integrating new equipment with old infrastructure, you need engineers who understand both the standards and the reality of what's in your substation.
What's included
Everything from scope to as-built.
N2 provides complete protection and control design packages — from the initial system assessment through final as-built documentation. We work with your existing infrastructure, your relay vendors, and your operations team, so the deliverables are usable the day we hand them over.
One-line diagrams
Updated single-line and three-line diagrams reflecting current and future system configuration.
AC/DC schematics
Complete control schematics and wiring diagrams for relay panels and control circuits.
Panel layout drawings
Physical layout drawings for new and modified relay panels and control houses.
As-built documentation
Final drawings that reflect what was actually installed — not what was originally designed.
Relay settings packages
Coordinated relay settings developed alongside the design, ready for commissioning.
Electromechanical replacement
Full design support for upgrading aging electromechanical relays to modern microprocessor units.
When do you need P&C design?
- Aging electromechanical relays that need upgrading to microprocessor units
- Panel documentation that doesn't match what's actually wired in the field
- New substation builds requiring a full protection and control design package
- Integrating new equipment — transformers, breakers, capacitor banks — into existing protection schemes
- System expansion requiring updated relay coordination
Service Detail
Protection schemes
- Line protection, distance and directional overcurrent
- Bus differential and transformer differential
- Breaker control and breaker failure
- Digital fault recording and SCADA interface
- Pilot and communication schemes: DCB, DCUB, POTT, DUTT, DTT
- Synchrophasor capability
Bus configurations
- Single breaker
- Main and transfer
- Breaker-and-a-half
- Double breaker, double bus
- Ring bus, with bypass and transfer bus schemes
Design deliverables
- Cable schedules and tripping diagrams
- Scopes of work and outage plans
- Bills of materials and vendor quotations
- Auxiliary power and battery system design
- Control building design and layout
- Peer review and QA to client standards
Voltage classes and platforms
- 4kV through 500kV
- SEL: 311, 311L, 411, 411L, 421, 351, 387, 387E, 451, 487B, 487E, 587Z
- GE L90; ABB; ERLphase
- Eaton/Cooper SG-4260 and SMP IO series
- Legacy electro-mechanical relays
- AutoCAD, AutoCAD Electrical, MicroStation, Bluebeam REVU
Frequently asked questions
Common questions
How long does a protection and control design package take?
Most relay panel design packages take 4–12 weeks from kickoff to final drawings, depending on the number of panels, system complexity, and vendor coordination required. We scope this specifically for your project before we start.
What's included in an electromechanical relay replacement project?
A full replacement project typically includes existing system documentation (if drawings are missing or outdated), new relay selection and vendor coordination, panel layout and schematic design, relay settings development, and final as-built documentation. We can also provide commissioning support.
Do you work with all relay manufacturers?
Yes. We have experience with SEL, GE/Multilin, ABB, ERLphase, Eaton/Cooper and other major protection relay platforms, as well as legacy electro-mechanical relays. We design around the manufacturer that fits your system and your team's existing familiarity.
Can you work from existing drawings that may be out of date?
Frequently. Many of our projects start with outdated or incomplete documentation. We field-verify existing conditions and build from what's actually installed — then produce drawings that reflect reality.
Ready to talk P&C?
Tell us what's in your substation.
We'll ask the right questions and give you a straight answer on what a P&C project would look like for your system.