GE ALPS - Line Protection Schemes

1-8 ALPS Advanced Line Protection System
GE Power Management
1.2 INTRODUCTION 1 PRODUCT DESCRIPTION
1
c) RIGHT RESISTIVE BLINDER
The right resistive blinder is a two input phase angle comparator. The input signals for the comparator are:
Operate: Iφ ′· RB 1 - Vφ
Polarize: Iφ ′· RB 1
where:
The magnitude of
RB 1 (Right Blinder for Zone 1) is the point at which the characteristic intersects the R
axis. The range of adjustment will be 0.1 to 500.0 ohms in 0.1 ohm steps.
The angle of RB 1 is be fixed based on the positive sequence line angle, the zero sequence line angle,
and the
K 0 factor. The angle is:
Iφ ′ is the compensated phase current, ( I
A
- I
0
) + K
0
1• I
0
The characteristic timer angle will be fixed at 90°. For the Zone 1 ground function, the operate and polarizing signals are:
1.2.5 LINE PROTECTION SCHEMES
The ALPS provides four zones of distance protection with overcurrent backup functions. The ALPS is a highly flexible sys-
tem: along with predefined protection schemes, it also has the ability to be programmed by the user. The custom program-
mability of the ALPS is discussed in the next section.
The ALPS pilot protection schemes are as follows:
• Permissive Underreach Transfer Trip (PUTT)
• Permissive Overreach Transfer Trip (POTT1)
• Permissive Overreach Transfer Trip with blocking functions (POTT2)
•Blocking
•Hybrid
• Phase Identified Channel
In addition, each of the above schemes includes up to four zones of step distance backup with individual timers for phase
and ground zones.
Phase A:
I
A
′· RB 1 – V
A
I
A
′· RB 1
Phase B:
I
B
′· RB 1 – V
B
I
B
′· RB 1
Phase C:
I
C
′· RB 1 – V
C
I
C
′· RB 1
where:
I
A
′ = ( I
A
- I
0
) + K
0
1· I
0
I
B
′ = ( I
B
- I
0
) + K
0
1· I
0
I
C
′ = ( I
C
- I
0
) + K
0
1· I
0
K
0
1 = | K
0
1| – (ZERSEQANG – POSSEQANG)
2 POSSEQANG
⋅
K 0ZERSEQANG
⋅
+
2
K 0
+
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