GE 845 Instruction Manual page 24

SPECIFICATIONS
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UNDERFREQUENCY (81U)
Pickup Level: ......................................................... 20.00 to 65.00 Hz in steps of 0.01
Dropout Level:...................................................... Pickup + 0.03 Hz
Pickup Time Delay:............................................. 0.000 to 6000.000 s in steps of 0.001s
Dropout Time Delay: ......................................... 0.000 to 6000.000 s in steps of 0.001s
Minimum Operating Voltage:........................ 0.000 to 1.250 x VT in steps of 0.001 x VT
Minimum Operating Current: ........................ 0.000 to 30.000 x CT in steps of 0.001 x CT
Level Accuracy:.................................................... ± 0.001 Hz
Timer Accuracy: .................................................. ± 3% of delay setting or ± ¼ cycle (whichever is greater) from
Operate Time: ...................................................... typically 7.5 cycles at 0.1 Hz/s change
Typical times are average Operate Times including variables such as frequency change
instance, test method, etc., and may vary by ± 0.5 cycles.
OVERFREQUENCY (81O)
Pickup Level: ......................................................... 20.00 to 65.00 Hz in steps of 0.01
Dropout Level:...................................................... Pickup - 0.03 Hz
Pickup Time Delay:............................................. 0.000 to 6000.000 s in steps of 0.001 s
Dropout Time Delay: ......................................... 0.000 to 6000.000 s in steps of 0.001 s
Minimum Operating Voltage:........................ 0.000 to 1.250 x VT in steps of 0.001 x VT
Level Accuracy:.................................................... ± 0.001 Hz
Timer Accuracy: .................................................. ± 3% of delay setting or ± ¼ cycle (whichever is greater) from
Operate Time: ...................................................... typically 7.5 cycles at 0.1 Hz/s change
Typical times are average Operate Times including variables such as frequency change
instance, test method, etc., and may vary by ± 0.5 cycles.
FREQUENCY RATE OF CHANGE (81R)
df/dt Trend:............................................................ Increasing, Decreasing, Bi-directional
df/dt Pickup Level:.............................................. 0.10 to 15.00 Hz/s in steps of 0.01 Hz/s
df/dt Dropout Level: .......................................... 96% of Pickup Level
df/dt Level Accuracy: ........................................ 80 mHz/s or 3.5%, whichever is greater
Minimum Frequency: ........................................ 20.00 to 80.00 Hz in steps of 0.01 Hz
Maximum Frequency:....................................... 20.00 to 80.00 Hz in steps of 0.01 Hz
Minimum Voltage Threshold: ........................ 0.000 to 1.250 x VT in steps of 0.001 x VT
Minimum Current Threshold: ........................ 0.000 to 30.000 x CT in steps of 0.001 x CT
Pickup Time Delay:............................................. 0.000 to 6000.000 s in steps of 0.001 s
Timer Accuracy: .................................................. ± 3% of delay setting or ± ¼ cycle (whichever is greater) from
95% Settling Time for df/dt: .......................... < 24 cycles
Operate Time: ...................................................... typically 10 cycles at 2 × Pickup
RTD PROTECTION
Pickup:...................................................................... 1°C to 250°C in steps of 1°C
Hysteresis:.............................................................. 2°C
Timer Accuracy: .................................................. <2 s
Elements:................................................................ Trip and Alarm
pickup to operate
typically 7 cycles at 0.3 Hz/s change
typically 6.5 cycles at 0.5 Hz/s change
pickup to operate
typically 7 cycles at 0.3 Hz/s change
typically 6.5 cycles at 0.5 Hz/s change
pickup to operate
845 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 1: INTRODUCTION