Testing & Commissioning
Network Integration Verification
Confirming the right device clears the fault, so a spur fault does not take out an entire feeder.
Protection coordination means the device closest to a fault operates first, disconnecting the smallest possible section of network. Get it wrong and a fault on a small spur trips the main incomer instead, taking out every customer on the feeder rather than a handful.
This is a separate commissioning step from functional testing, and it is the one most often skipped. A recloser can pass every test on its own and still be badly coordinated with what sits upstream of it.
What verification covers
- Review of upstream and downstream protection settings
- Coordination margin assessment across the fault range
- Grading verification between devices in series
- Confirmation of discrimination for both phase and earth faults
- Adjustment of settings where grading is inadequate
- Record of the coordinated scheme as commissioned
What matters in practice
-
Grading needs margin
Two devices that operate at almost the same time are not coordinated. Adequate margin between them is what produces reliable discrimination.
-
Both phase and earth
A scheme that grades correctly for phase faults can still be badly coordinated for earth faults. Both get checked.
-
Across the fault range
Coordination that holds at maximum fault level can fail at minimum. The margin is assessed across the range, not at one point.
-
Documented for the next change
The coordinated scheme is recorded, so the next person adding a device to this feeder can grade against it.
Related services
Concerned about coordination?
Tell us what you need and where the site is, and we will scope the work and quote it.