2-38 L90 LINE CURRENT DIFFERENTIAL SYSTEM – INSTRUCTION MANUAL
SPECIFICATIONS CHAPTER 2: PRODUCT DESCRIPTION
2
Dropout level: pickup – 0.03 Hz
Level accuracy: ±0.001 Hz
Time delay: 0 to 65.535 s in steps of 0.001
Timer accuracy: ±3% of operate time or ±1/4 cycle (whichever is greater)
Operate time: typically 4 cycles at 0.1 Hz/s change
typically 3.5 cycles at 0.3 Hz/s change
typically 3 cycles at 0.5 Hz/s change
Typical times are average operate times including variables such as frequency change instance, test method, and so on, and can vary by
±0.5 cycles.
RATE OF CHANGE OF FREQUENCY
df/dt trend: increasing, decreasing, bi-directional
df/dt pickup level: 0.10 to 15.00 Hz/s in steps of 0.01
df/dt dropout level: 96% of pickup
df/dt level accuracy: 80 mHz/s or 3.5%, whichever is greater
Overvoltage supv.: 0.100 to 3.000 pu in steps of 0.001
Overcurrent supv.: 0.020 to 30.000 pu in steps of 0.001
Pickup delay: 0 to 65.535 s in steps of 0.001
Reset delay: 0 to 65.535 s in steps of 0.001
Timer accuracy: ±3% of operate time or ±1/4 cycle (whichever is greater)
95% settling time for df/dt: <24 cycles
Operate time: typically 9.5 cycles at 2 × pickup
typically 8.5 cycles at 3 × pickup
typically 6.5 cycles at 5 × pickup
Typical times are average operate times including variables such as frequency change instance, test method, and so on, and can vary by
±0.5 cycles.
BREAKER FAILURE
Mode: 1-pole, 3-pole
Current supervision: phase, neutral current
Current supv. pickup: 0.020 to 30.000 pu in steps of 0.001
Current supv. dropout: 97 to 98% of pickup
Current supv. accuracy:
0.1 to 2.0 × CT rating: ±0.75% of reading or ±2% of rated (whichever is greater)
above 2 × CT rating: ±2.5% of reading
BREAKER ARCING CURRENT
Principle: accumulates breaker duty (I
2
t) and measures fault duration
Initiation: programmable per phase from any FlexLogic operand
Compensation for auxiliary relays: 0 to 65.535 s in steps of 0.001
Alarm threshold: 0 to 50000 kA
2
-cycle in steps of 1
Fault duration accuracy: 0.25 of a power cycle
Availability: 1 per CT bank with a minimum of 2
BREAKER FLASHOVER
Operating quantity: phase current, voltage, and voltage difference
Pickup level voltage: 0.004 to 1.500 pu in steps of 0.001
Dropout level voltage: 97 to 98% of pickup
Pickup level current: 0.020 to 1.500 pu in steps of 0.001
Dropout level current: 97 to 98% of pickup
Level accuracy: ±0.5% or ±0.1% of rated, whichever is greater
Pickup delay: 0 to 65.535 s in steps of 0.001
Timer accuracy: ±3% of operate time or ±42 ms, whichever is greater
Operate time: <42 ms at 1.10 × pickup at 60 Hz
BREAKER RESTRIKE
Principle: detection of high-frequency overcurrent condition ¼ cycle after breaker opens
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