Feeder Terminal Units (FTU)

Pole-top control, protection and FLISR logic in one cabinet.

A feeder terminal unit, or FTU, is the intelligence you bolt to a pole so a switch, a sectionalizer or a recloser stops being a manual device. It measures the feeder, decides locally when the master station is unreachable, and reports to distribution SCADA when it is. The result is a feeder that can isolate a faulted section and restore the healthy sections on its own, in the time it takes the logic to run rather than the time it takes a crew to arrive.

The unit takes 4 current channels and 6 voltage channels, plus RTD and 4–20 mA inputs for transformer and environmental points, and drives 10 binary inputs against 4 outputs with 30 W breaking capacity. Protection is not a token function here: definite time plus 26 IDMT curves plus 24 user-defined curves means the FTU coordinates with what is already on the feeder instead of forcing a re-study. FDIR self-healing runs by current counter, voltage-time, loop or automatic changeover. Ten waveform records of up to 10 s at 128 samples per cycle give you the event to analyze afterwards, and RS-232, RS-485 and Ethernet carry IEC 60870-5-101, IEC 60870-5-104, DNP3.0 and Modbus to whatever master station you already run.

Why it matters

• FDIR logic by current counter, voltage-time, loop or automatic changeover means self-healing works with the sectionalizing scheme you already have, not only with a full communications-assisted scheme.

• 26 IDMT curves plus 24 user-defined curves let the FTU drop into an existing coordination study. You are not re-grading the feeder to accommodate the hardware.

• Two 12 V / 12 Ah sealed lead-acid batteries give 24 h autonomy, so the unit keeps reporting and keeps switching through the outage it is there to manage.

• Waveform capture at 128 samples per cycle turns a recurring nuisance trip into evidence instead of an argument.

• IP55 and −25 °C to +70 °C are pole-top ratings, not panel-room ratings.

Ratings

• Analog inputs: 4 current channels and 6 voltage channels; RTD and 4–20 mA inputs

• Binary I/O: 10 inputs / 4 outputs (30 W breaking capacity)

• CT ratio: 1 A / 5 A; voltage sensor 0–8 V RMS

• Supply: 100–240 VAC input, 24 VDC operation (20–29 VDC); <30 W

• Backup: 2 × 12 V / 12 Ah sealed lead-acid, 24 h autonomy

• Ports: RS-232, RS-485, Ethernet

• Protocols: IEC 60870-5-101, IEC 60870-5-104, DNP3.0, Modbus

• Curves: Definite time plus 26 IDMT curves plus 24 user-defined curves

• Automation: FDIR / self-healing logic — current counter, voltage-time, loop, automatic changeover

• Records: 10 waveform records of up to 10 s at 128 samples per cycle

• Ingress protection: IP55

• Temperature: −25 °C to +70 °C

Standards

• IEEE C37.90

• DNP3.0

• IEC 60870-5-101/-104

• IEC 60255

Applications

• Pole-mounted switch and recloser control

• Feeder automation and FLISR

• Sectionalizer control

• Distribution SCADA rollouts

Questions engineers ask

What is the difference between an FTU and a recloser control? A recloser control is dedicated to one device and its reclosing sequence. An FTU is a feeder automation controller: it operates pole-mounted switches, sectionalizers or reclosers, carries full protection with 26 IDMT curves, runs FDIR self-healing logic, and concentrates analog and binary points for SCADA over IEC 60870-5-104 or DNP3.0.

Will the FTU keep working during an outage? Yes. It runs from a 100–240 VAC supply at under 30 W, and two 12 V / 12 Ah sealed lead-acid batteries provide 24 hours of autonomy. That covers the period when the unit is most needed — isolating the faulted section, reporting status and executing the restoration sequence while the feeder around it is dead.