5-374 L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
CONTROL ELEMENTS CHAPTER 5: SETTINGS
5
The broken conductor function detects a transmission line broken conductor condition or a single-pole breaker
malfunction condition by checking the phase current input signals and the I_2 / I_1 ratio. The intent is to detect a single-
phase broken conductor only. As such, two-phase or three-phase broken conductors cannot be detected.
To distinguish between single-phase disappearance and system disturbance in all three phases (such as load change and
switching), the broken conductor element monitors the change in all three phase currents at the present instance and at
four cycles previous. It also monitors changes in the I_2 / I_1 ratio, I_1 minimum, and I_1 maximum.
Do not use the broken conductor function to respond to fault transients and single-pole tripping/reclosing conditions.
Therefore, program the time delay to a sufficient length to ensure coordination with the breaker dead time of the recloser
function.
BROKEN CONDUCTOR 1 FUNCTION — This setting enables and disables the broken conductor function.
BROKEN CONDUCTOR 1 SOURCE — Selects a signal source used to provide three-phase current inputs to this function.
BROKEN CONDUCTOR 1 I2/I1 RATIO — This setting specifies the ratio of negative-sequence current to positive-sequence
current. When one phase conductor is broken, the I_2 / I_1 ratio with a balanced remaining two phases is 50%. So
normally you this setting below 50% (for example, to 30%).
BROKEN CONDUCTOR 1 I1 MIN — This setting specifies the minimum positive-sequence current supervision level. Ensure this
setting is programmed to a sufficient level to prevent I_2 / I_1 from erratic pickup due to a low I_1 signal. However, do not
set this setting too high, since the broken conductor condition cannot be detected under light load conditions when I_1 is
less than the value specified by this setting.
BROKEN CONDUCTOR 1 I1 MAX — This setting specifies the maximum I_1 level allowed for the broken conductor function to
operate. When I_1 exceeds this setting, this it is considered a fault. In order for this function to not respond to any fault
conditions, set this setting to less than the maximum load current.
BROKEN CONDUCTOR 1 PKP DELAY — This setting specifies the pickup time delay for this function to operate after assertion
of the broken conductor pickup FlexLogic operand.

BROKEN CONDUCTOR 1
I1 MAX: 1.50 pu
Range: 0.05 to 5.00 pu in steps of 0.01

BROKEN CONDUCTOR 1
PKP DELAY: 20.000 s
Range: 0.000 to 65.535 s in steps of 0.001

BROKEN CONDCT 1 BLK:
Off
Range: FlexLogic operand

BROKEN CONDUCTOR 1
TARGET: Self-reset
Range: Self-reset, Latched, Disabled

BROKEN CONDUCTOR 1
EVENTS: Disabled
Range: Disabled, Enabled
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