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Protection Functions: Characteristics

The document describes the protection functions, settings, and measurements of a circuit breaker. It lists the protection functions as 50/51, 50N/51N for overcurrent and earth fault. It provides details on the tripping curves, set points, and accuracy of the definite time and inverse time overcurrent protection. It also describes the thermal protection function 49, its set points, time delay, and accuracy. Finally, it specifies the measurement ranges and accuracy for measured rms currents, peak demands, and earth faults.

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45 views2 pages

Protection Functions: Characteristics

The document describes the protection functions, settings, and measurements of a circuit breaker. It lists the protection functions as 50/51, 50N/51N for overcurrent and earth fault. It provides details on the tripping curves, set points, and accuracy of the definite time and inverse time overcurrent protection. It also describes the thermal protection function 49, its set points, time delay, and accuracy. Finally, it specifies the measurement ranges and accuracy for measured rms currents, peak demands, and earth faults.

Uploaded by

Pamungkas
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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Characteristics Protection functions

Sec Protection function 50/51, 50N/51N


DE53195

1000
Tripping curve
b DT: Definite time
b SIT/A: IEC standard inverse
b VIT/B: IEC very inverse
b LTI/B: IEC long-time inverse
b EIT/C: IEC extremely inverse
100 b MI/D: IEEE moderately inverse
b VI/E: IEEE very inverse
b EI/F: IEEE extremely inverse
b RI
I>, I>> set points
DT curve 0.1...24 In (minimum: 1 A)
10
IDMT curves 0.1...2,4 In (minimum: 1 A)
LTI/B
Accuracy ±5 % or ±0.02 In
RI Drop out/pick up ratio 95 %
SIT/A Transient overshoot < 10 %
Io>, Io>> set points
1
DT curve Standard version Setting range: 0.1…24 Ino
VIT/B
(minimum: 1 A)
Sensitive version Setting range: 0.01…2.4 Ino
(minimum: 0.1 A)
EIT/C High sensitivity Rating 0.2…24 A Setting range: 0.0004…0.05 Ino
version (Ino = 470 A)
0.1
I/I> Rating 2.0…240 A Setting range: 0.004…0.5 Ino
1 2 5 10 20
or (Ino = 470 A)
Io/Io> IDMT curves Standard version Setting range: 0.2…2.4 Ino
IEC curves SI, VI, LTI, EI and RI curve. (minimum: 1 A)
Sensitive version Setting range: 0.01…0.24 Ino
(minimum: 0.1 A)
Sec
DE53194

High sensitivity Rating 0.2…24 A Setting range: 0.0004…0.005 Ino


1000
version (Ino = 470 A)
Rating 2.0…240 A Setting range: 0.004…0.05 Ino
(Ino = 470 A)
Accuracy ±5 % ou ±0.02 Ino
Drop out/pick up ratio 95 %
100
Transient overshoot < 10 %
Time delay
DT curve 0.05...300 s
IEC, RI curves TMS: 0.02...2 (step: 0.01)
10
IEEE curve TD: 0.5...15 (step: 0.1)
Accuracy DT curve: ±2% or ±20 ms
IDMT curves: ±5% or ±20 ms
MI Timer hold Selection: ON/OFF. Common setting
VI for I> and Io> set points
1
Accuracy ±2 % or ±20 ms
EI
Characteristic times
Operation time < 40 ms at 2 x set point (typically 25 ms)
Overshoot time < 40 ms at 2 x set point
0.1
Reset time < 50 ms at 2 x set point
1 2 5 10 20 I/I>
or
Io/Io>
IEEE curves MI, VI, EI.
Protection function 49RMS
Set points
Alarm set point Setting range 50...100 % of permissible thermal capacity
Trip set point Setting range 0.1...2.4 In (value of permissible current)
Accuracy ±5 % or ±0,02 In
Drop out/pick up ratio 95 %
Time delay
Time constant Setting range 1...120 mn in 1 mn. steps
Tripping-time accuracy ±2 % or ±2 s

15
Characteristics Measurements

Measured characteristic Value


Rms phase current and peak Measurement range 0.1 In...1.5 In
demand currents Accuracy ±1 % typical at In
±2 % 0,3 In... 1.5 In
±5 % 0.1 In...0.3 In
Earth-fault current Range for standard version 0.1 Ino...1.5 Ino (or In)
Range for sensitive version 0.01 Ino...1.5 Ino (or In)
Range for high sensitivity 0.25...24 A primary or
version 2.5...240 A primary
Depending on the rating
Accuracy ±1 % typical at Ino (or In)
±2 % 0.3 Ino...1.5 Ino (or In)
±5 % 0.005 Ino...0.3 Ino (or In)
Phase tripping currentt Measurement range 0.1 In...40 In
Accuracy ±5 %
Earth-fault tripping current Range for standard version 0.1 Ino...40 Ino (or In)
Range for sensitive version 0.01 Ino...4 Ino (or In)
Range for high sensitivity 0.2...40 A primary or
version 2...400 A primary
Depending on the rating
Accuracy ±5 %

16

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