CYG PRS-7367 - Flux-Balance Based Differential Protection 87 MFDIF; Overview

Protection Functions
PRS-7367 221
No
Name
Values(Range)
Unit
Step
Default
Description
1.
87MP_DIF_Ie
1~20In
-
1
5In
Machine Rated Current
Enable
3.
87MP_DIF_AlmEna
0~1
-
1
0
Differential Current Off limit Alarm
Enable
4.
87MP_DIF_CTBrkEna
0~1
-
1
0
CT Supervision Block Enable
5.
87MP_DIF_CTSatEna
0~1
-
1
0
CT Saturation Block Enable
6.
87MP_DIF_Idh
1.00~10.00Ie
A
0.01Ie
5Ie
Instantaneous high operate value
7.
87MP_DIF_Idl
0.05~4Ie
A
0.01Ie
0.05Ie
Biased low operate value
8.
87MP_DIF_Ir1
0.00~1.00Ie
A
0.01Ie
0.8Ie
The biased current of End section
1
9.
87MP_DIF_Ir2
1.00~5Ie
A
0.01Ie
3Ie
The biased current of End section
2
10.
87MP_DIF_k1
0.10~0.60
-
0.01
0.60
Slope section 2
11.
87MP_DIF_k2
0.10~1
-
0.01
1
Slope section 3, default value is 1.
If the k2 is equal to k1, the Slope
number is 2.
3.47 Flux-balance based differential protection 87MFDIF
3.47.1 Overview
Flux balance differential protection is used as the main protection for machines (motor or
generator) in case of phase to phase short circuits. The magnetic balance differential protection is
installed at the entrance of the motor or generator, and the protection range is only within the
internal motor or generator.
3.47.1.1 Function Block
87MF_DIF
ID3P
Str
Op
Block
Figure 3.47-1 Function block
3.47.1.2 Signals
Table 3.47-1 Input signal
Signal
Description
ID3P
The differential current, the default value is I3P2
Block
This signal blocks all the binary output signals of the function