GE Multilin 489 User Manual

5–40 489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 5: SETPOINTS
The differential element for phase A will operate when:
(EQ 5.12)
where the following hold:
(EQ 5.13)
(EQ 5.14)
(EQ 5.15)
I
A
= phase current measured at the output CT (EQ 5.16)
I
a
= phase current measured at the neutral end CT (EQ 5.17)
Differential elements for phase B and phase C operate in the same manner.
FIGURE 5–4: Differential Elements
5.6.9 Ground Directional
PATH: SETPOINTS ZV S5 CURRENT ELEM. ZV GROUND DIRECTIONAL
I
operate
kI
restraint
×>
I
operate
I
A
I
a
+ operate current==
I
restraint
I
A
I
a
+
2
-------------------- restraint current==
k characteristic slope of the differential element in percent=
kSlope1 if I
R
2CT×<= ; kSlope2 if I
R
2CT×≥=
OPERATE
REGION
I (multiples of CT)
RESTRAINT
I
(multiples of CT)
OPERATE
Slope2=20%
808790A2.CDR
Slope1=10%
Minimum Pickup = 0.10 x CT
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0 0.5 1 1.5 2 2.5 3 3.5 4
4.5 5
0
1 GROUND [Z]
DIRECTIONAL
SUPERVISE WITH
DIGITAL INPUTS: Yes
Range: Yes, No.
MESSAGE
GROUND DIRECTIONAL
MTA: 0°
Range: 0°, 90°, 180°, 270°
MTA = Maximum Torque Angle
MESSAGE
GROUND DIRECTIONAL
ALARM: Off
Range: Off, Latched, Unlatched
MESSAGE
ASSIGN ALARM
RELAYS (2-5): ---5
Range: Any combination of Relays 2 to
5
MESSAGE
GROUND DIR. ALARM
PICKUP: 0.05 x CT
Range: 0.05 to 20.00 × CT in steps of
0.01
Courtesy of NationalSwitchgear.com

GE Multilin 489 Specifications

General

Brand	GE
Model	Multilin 489
Category	Relays
Language	English