Time-current coordination

ORIENT

What this module is for

Build a coordinated curve set and identify miscoordination.

PREDICT

Commit to an answer first

Predicting before you experiment is what makes the result stick. There is no penalty for being wrong here.

If curves cross at high current, what fails?

Nothing, as long as they separate at low currentSelectivity in that current range — the upstream device may trip firstOnly arc flash energyOnly the instantaneous element

EXPERIMENT

Guided scenario in Protective Relay Coordination / TCC Visualizer

Coordinate a downstream and upstream device across the fault range.

Launch lab Lab details

Plot a downstream feeder device and an upstream main.
Check separation across the whole current range, not one point.
Introduce an overlap and identify the current range where selectivity is lost.

CHECK

Quick retrieval check

Coordination is evaluated:

At the maximum fault current onlyAt the minimum fault current onlyAcross the range of expected fault currentsAt load current only

APPLY

Put it in your own words

Describe the trade-off between fast clearing for arc flash and coordination separation for selectivity.

Your reflection

Finish this module

Still outstanding before this module can be marked complete:

Prediction recorded
Lab opened
Guided scenario steps confirmed
Knowledge check submitted
Reflection confirmed

Saved on this device. Sign in to sync privately to your account and resume on another device.