Protective Device Coordination Studies
A coordination study answers one question: when a fault occurs, does the nearest upstream device clear it, and does everything above that device stay closed? Get it wrong and a fault on one branch takes out the whole plant.
Furano Pacific Consulting prepares protective device coordination studies for industrial, institutional and commercial facilities across British Columbia, Alberta and Saskatchewan.
What the study covers, and why it matters
Time-current characteristic curves for the full protection chain, from the utility interface down to branch protection, plotted so that selectivity can be demonstrated rather than assumed.
Relay setting recommendations, including phase and ground overcurrent, and instantaneous elements where selectivity allows them.
Fuse and breaker selection review, checking that installed devices can actually be coordinated at the available fault levels.
Identification of miscoordination in the existing system, ranked by consequence.
Why it matters beyond nuisance tripping
Coordination is the main lever available for reducing arc flash incident energy. Incident energy is driven more by clearing time than by fault current, so a device that clears in six cycles instead of thirty changes the hazard category at that bus.
That makes the coordination study and the arc flash study two halves of the same exercise. We normally recommend running them together, because recommendations from one change the inputs to the other.
Where it is required
New construction where the electrical design must be demonstrated as selective before energization.
Facilities that have grown incrementally, where each addition was coordinated against its own feeder but never against the system as a whole.
After a utility upgrade changes available fault current at the service.
Following an unexplained outage where an upstream device operated and the cause was never established.
Deliverables
Sealed report with methodology, assumptions and findings. TCC plots for each coordination pair. A settings table ready to hand to the commissioning technician. Updated single-line diagrams. The model file for future re-analysis.
Common questions
Can coordination be done without a short circuit study? No. Coordination is plotted against the fault current available at each device, so the short circuit model has to exist first. A coordination study offered without one is a curve-drawing exercise, not an engineering result.
Will better coordination reduce my arc flash incident energy? Usually yes, and it is the cheapest lever available. Incident energy scales with clearing time, so shaving a device from 0.5 s to 0.1 s does more than any PPE decision. Where a setting change cannot get there, we look at maintenance switches, zone-selective interlocking or arc energy reduction functions.
What if my relays are electromechanical? They coordinate, but the setting granularity is coarse and the curves drift with age. We model them as found, report where the coordination margin is thin, and flag the devices where a modern relay would pay for itself in selectivity alone.
Do you provide the settings, or just the report? Both. The deliverable includes a device-by-device settings schedule written in the form the technician actually enters, not a curve the field is left to interpret.
What software do you model in? ETAP and EasyPower. We hand back the model file, so the next change to your system is a revision rather than a rebuild.