Protection coordination: only what should trip, trips
We review and adjust your protections so that, in the event of a fault, only the breaker closest to the problem opens. That way a fault in one motor doesn't shut down the whole plant, and downtime is reduced.
What is protection coordination?
In a well-coordinated installation, each protective device has a job: the motor protection protects the motor, the feeder protection protects the feeder, and the main breaker acts only if the others did not. When the settings are not coordinated, a small fault trips the main breaker and all production is lost.
The protection coordination study plots the time-current curves of relays, breakers and fuses along each path, from the service entrance to the loads, and defines the settings that achieve selectivity while still protecting the equipment. It also provides the clearing times used in the Arc Flash study.
When is it needed?
- The main breaker trips due to faults in a single piece of equipment.
- Your breakers still have their factory settings and have never been reviewed.
- You have medium-voltage relays without a settings study.
- There were expansions, a new transformer or breaker replacements.
- You are going to perform the Arc Flash study: trip times determine the incident energy.
- You have recurring shutdowns with no clear cause.
What it includes
The final scope is defined with you, based on your installation and what you need to solve.
Protection inventory
Relays, breakers with trip units, molded-case breakers and fuses, with their current settings.
Time-current curves
Plots per path showing how each device acts relative to the ones upstream and downstream.
Settings table
Recommended pickup, time delay, instantaneous and ground fault values for each device.
Equipment protection
Verification against the damage curves of transformers and cables, and motor starting.
Implementation (optional)
Application of the settings on site and verification, during the agreed shutdown window.
Unresolvable points
Equipment that cannot be coordinated with what is installed, and the recommended alternative.
What we need to perform the study
The basics are enough to quote. If you are missing some data, don't stop: we gather it on site as part of the service.
To perform the study
Requested once the service is confirmed. We help you gather it.
- Current short circuit study, or the data needed to perform it.
- Brand, model and current settings of relays and breakers (photos of the trip units are useful).
- Type, rating and curve of the installed fuses.
- Transformer nameplate data.
- Power and starting method of the main motors.
- CFE protection settings at the connection point, which the coordination must respect.
- Recent trip history, if you have it.
Your information is treated as confidential and is used only for your project.
How the study is performed
Information review
We receive the single-line diagram, the short circuit study and the current settings.
Site survey
We verify the protections and their actual settings on site.
Selectivity study
We plot the curves and define the recommended settings.
Handover and implementation
We deliver the report and, if you wish, apply the settings.
What people ask us most
What is selectivity?
It is the condition in which, during a fault, only the protective device closest to the fault point operates and the rest of the installation keeps running.
Why is the short circuit study needed?
Protection curves are compared against the fault currents at each point. Without knowing those currents, reliable settings cannot be defined.
Can the settings be applied without shutting down?
It depends on the device. Some settings require de-energizing or working on the equipment; we schedule them with you in a shutdown window and under your safety procedures.
What if my breakers don't allow adjustment?
The study identifies it and proposes the alternative: replacing the device, using fuses with a different curve or changing the configuration.
Do you have a case at your plant?
Tell us what you need to solve and what information you have. A specialist will reply with the scope and next steps.