LaZer II FDIR

SmartDMS LaZer II FDIR LaZer II FDIR helps operators minimize the downtime caused by outages that trip and lock out breakers in a distribution substation. Although FDIR can use load flow, it can also be operated without using load flow. FDIR’s fault location algorithm is based on analyzing the pattern of fault targets at fault indicators.

When a breaker lockout is detected:

FDIR analyzes the pattern of fault targets to determine the fault location.
FDIR opens a new blank switch order record.
If the fault is between the breaker and the first level of closed switches, FDIR adds commands to the switch order to open the first level of closed switches. The breaker is left open. This isolates the fault.
If the fault is downstream of the first level of closed switches, FDIR isolates the fault by adding commands to open all closed switches around the faulted area. FDIR then adds a command to close the breaker. This restores service above the fault.
FDIR then analyzes the area beyond each opened switch to see if the area downstream can be transferred to another feeder.
Using connected KVA data defined on all the feeder line sections, FDIR computes the feeder’s total and lost connected KVA, and scales these by the pre-fault feeder load values to compute the required load transfers.
For every area to transfer, FDIR constructs a list of possible ties to other feeders, and selects the one that has the greatest load margin after the "close" operation. Only feeders that have FDIR enabled, are energized, have the recloser unblocked, etc are considered. For each transfer, a command to close a tie switch is added to the switch order.
If the required load transfer is too large for any single adjacent feeder, but the area contains one or more closed switches inside it, FDIR will evaluate whether it is feasible to segment the area by opening a switch and then transfer one segment only, or even both segments (to two different feeders). If feasible, the appropriate commands are added to the switch order.
If the segmented transfer list contains mutually exclusive operations (e.g. connecting both segments to the same transfer feeder), FDIR will give priority to the segment that has more line sections with critical loads. If both segments have the same number of critical loads, priority is then given to the number of customers restored. If that number is the same, then priority is given to the amount of load restored.
For each transfer to another feeder, FDIR adds commands to block the recloser of the target feeder, close the tie and then unblock the recloser.
When all the switching operations are complete, FDIR adds commands to the fault indicators to reset the fault targets.
If FDIR is in automatic mode, the switch order is executed automatically as it’s built. On each load transfer in automatic mode, after closing the tie, FDIR monitors the status of the target feeder to check that it does not trip. If the feeder breaker of the target feeder trips, FDIR will open the switch that was just closed, restores the feeder by closing the feeder breaker and unblocking the recloser, and does not complete the restoration process.
If FDIR is in semi-automatic mode, the switch order is left for the operator to review and execute manually.
The following are some points that are important to note about the FDIR process:
FDIR does not require any programming. FDIR does not require pre-defined “normal” network configurations, and can handle any radial network configuration. No adjustments are required when the network is reconfigured (e.g. for manual load transfers or by previous FDIR operations).
FDIR can be enabled or disabled on a per feeder basis. There is also a global enable/disable control for FDIR.
FDIR can be operated on a per feeder basis in either Semi-Automatic or Automatic mode.
FDIR does not use switches that have control-inhibiting tags. Nor does it makes use of devices (switches or fault indicators) that are telemetry failed.
If a control error occurs (e.g. a switch or breaker does not change to the expected state), FDIR switches from Automatic to Semi-Automatic mode and continues its analysis in semi-automatic mode. The switch order will then contain a mix of executed steps (executed prior to the control error) and unexecuted steps. The unexecuted steps can be completed by the operator.
All of the decision-making of the FDIR program operation is logged in the SCADA database, and can be reported by feeder and by event.