GE ALPS - Page 18

1-6 ALPS Advanced Line Protection System
GE Power Management
1.2 INTRODUCTION 1 PRODUCT DESCRIPTION
1
Figure 1–1: GROUND DISTANCE QUADRILATERAL CHARACTERISTIC
In the ALPS relay the four straight lines of the quadrilateral characteristic are developed by a combination of the following
three characteristics:
1. Reactance characteristic (section 1). The tilt of the reactance characteristic is determined by the characteristic timer
setting. The range of the setting is 80° to 155° in 1° steps.
2. Restricted directional characteristic (sections 2 and 4)
3. Right (positive) resistive blinder (section 3)
The following definitions pertain to all of the distance functions:
I
A
= phase A current at relay
I
B
= phase B current at relay
I
C
= phase C current at relay
I
0
= zero-sequence current at relay
V
A
= phase A to ground voltage at relay
V
B
= phase B to ground voltage at relay
V
C
= phase C to ground voltage at relay
X
1
= positive-sequence component of X
X
2
= negative-sequence component of X
X
M
= memory (pre-fault) value of X
Z x
1
= Zone x positive-sequence reach setting: ZxR ∠ POSSEQANG
Z
x
0
= Zone x zero-sequence reach setting: ZxR ∠ ZERSEQANG
Note: The magnitudes of
Zx
1
and Zx
0
are identical - these quantities differ in phase angle only.
K
0
1 = Zone 1 zero-sequence compensation factor: Z1K0
K
0
= zero-sequence compensation factor
a) REACTANCE CHARACTERSTIC
The reactance characteristic used for the ground quadrilateral is the similar as the existing negative / zero sequence phase
angle comparator reactance characteristic. The function has been modified by the addition of a fourth comparator input
(Pol. #3). The operate and polarizing signals used in this function are:
Operate:
Iφ ′ Z – Vφ
Pol.# 1: I
0
Z
1
Pol.# 2: I
2
Z
1
Pol.# 3: I
1 F
Z
1
where: Iφ ′ Z is the compensated IZ product
Z
1
is the positive sequence replica impedance
Vφ is the phase to ground voltage
I
0
is the zero sequence current component
I
2
is the negative sequence current component, referenced to the proper phase.
I
1 F
is the fault component of the positive sequence current component, referenced to the proper phase.
The pre-fault load current is removed from this quantity.
R
X
1
3
2
4