Fault selective device for DC feeder circuits(With fault waveform and maximum ΔI transmission function)
This device detects the current increase ( ΔI) when a short circuitor ground fault occurs on a feeder circuit for a DC electricrailway, and transmits a signal for the circuit breaker to open.
A function to transmit the fault waveform and the maximum ΔI
value can be added upon request.

Detection of current
increase (ΔI)
Monitor for faults
on the power
supply circuit.

Transformer substation
Fault SelectiveEquipment (FS)

Ethernet Connection
Adapter (IF)DC bus bar
1ApoweFUSEr(button onTV,etc.)

trip

Maximum ΔI value
Failure waveform

onTrip at preset
value or higher
Short circuit
and ground
Fault failurecircuit
breaker
openOFFdata transmission

RTULANElectrical
wire

Fault detection
transformer (FD)

Operation control
center

3456C
1234M

RailPower supply
section (PWB)

Purpose and role of the device
This system focuses on the difference in the current increase (ΔI) between the trainload current and the fault current, and by constantly monitoring ΔI, it selects anddetects only the fault current and outputs an open signal to the DC high-speed circuit
breaker to immediately stop the electricity supply.
In addition, the system has a function to transmit the presence or absence ofabnormalities in data transmission, fault current waveform, and maximum ΔI value
directly to a sub-station of a distant monitoring device (far system) without going
through the distribution panel, which enables analysis of faults in power commands,
etc., and contributes to reducing downtime.

Transmission of maximum ΔI value and fault waveform
When the maximum ΔI value is updated, the ΔI value is transmitted to the powercommand.
When a fault is detected and a breaker open signal is sent, the fault current waveform
is transmitted to the power command.

Time Synchronization Function
A new function has been added to synchronize the time in the fault selector withthe remote ｔｅｒminal unit.

type

MEFK4-U2-1(FS) / DF-8DS(FD)TS-13-1T2(IF) / SF-3ST2(PWB)

Mounting Unit
(Max. numberof units to bemounted)

ΔI unit 5 units (single system)/control unit 1 unit/printer unit 1 unit (option)※Fault waveforms are recorded for 10 phenomena andcan be printed with the printer unit.

Rated current

Failure detection rating 4000A

regulating
current

200A division of regulated current 1000A to 4000A

accuracy

The detection margin of each setpoint is within ±2.5% at α=50±5

possessionfunction

ΔI separation function Base current characteristics Regenerative lapse
characteristics Section compensation function
Sensitivity change function at re-closing Shared line switching function

transmitteddata(1) Waveform data: Current waveform data at the time of failure (all lines).
Current value between 100ms before and 150ms after fault detection(0.8ms sampling)(2)Maximum ΔI value: The maximum value of ΔI that has occurred in the past.
The maximum value of ΔI that the fault selector has detected so far istransmitted (all lines).
(3) Time setting data: Time setting from remote terminal unit to Ethernet
connection adapter
It is possible to set the device time of the fault selection device
by sending data.
(4)Inspection data: For checking the communication between
the remote terminal unit and the Ethernet connection adapter.

communicationsystem

Ethernet 100BaseT, 10BaseT (LAN)control power
supplyDC 100V/110V (variation range 80V to 132V)

Dimensions/Weight[FS] H370mm x W330mm x D387.5mm / approx. 17kg
[FD] H400mm x W400mm x D125mm / Approx. 16kg
(Primary through hole: 150mm x 150mm)[IF] H224mm x W100mm x D275mm / Approx. 16kg
[PWB] H260mm × W430mm × D247mm / approx. 11kg

MEFK4-U2-1(FS)DF-8DS（FD)