Rtd Accuracy - GE Multilin 489 Instruction Manual

CHAPTER 7: TESTING
7.2.6

RTD Accuracy

489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
Courtesy of NationalSwitchgear.com
1
2
I -- - I ( a I aI
= + +
ns a b
3
1
-- - 780 0° ( ∠ (
= +
3
1
-- - 780 0°
( ∠ 1000 127°
= +
3
1
-- - 780 601.8 (
= –
3
141.2
= –
I
ns
⇒
%I -------- - × 100 14%
= =
ns
FLA
Therefore, the negative sequence current is 14% of FLA. The specification for negative-
sequence current accuracy is per output current inputs. Perform the steps below to verify
accuracy.
In the
GENERATOR RATED MVA: "
VOLTAGE PHASE-PHASE:
Note that setting
VOLTAGE PHASE-PHASE
is for testing purposes only!
In the
PHASE CT PRIMARY:
Inject the values shown in the table below and verify accuracy of the
measured values.
View the measured values in the
METERING
Injected Current
1 A Unit
Ia = 0.78 A ∠0° Ia = 3.9 A ∠0°
Ib = 1 A ∠113° lag Ib = 5 A ∠113° lag
Ic = 1 A ∠247° lag Ic = 5 A ∠247° lag
Ia = 1.56 A ∠0° Ia = 7.8 A ∠0°
Ib = 2 A ∠113° lag Ib = 10 A ∠113° lag
Ic = 2 A ∠247° lag Ic = 10 A ∠247° lag
Ia = 0.39 A ∠0° Ia = 1.95 A ∠0°
Ib = 0.5 A ∠113° lag Ib = 2.5 A ∠113° lag
Ic = 0.5 A ∠247° lag Ic = 2.5 A ∠247° lag
The specification for RTD input accuracy is ±2° for Platinum/Nickel and ±5° for Copper.
Perform the steps below.
In the
RTD TYPE
RTD #1
) where a 1 120° ∠
= =
c
2
∠ ) ( ∠ ) (
1 120° 1000 113° 1 120°
– +
∠ 1000 233° ∠ )
+
j798.6 601.8 j798.6 )
+ – –
S2 SYSTEM SETUP GEN. PARAMETERS
1.04"
"600"
to "600" is equivalent to setting FLA = 1000 A. This
S2 SYSTEM SETUP CURRENT SENSING
"
1000 A"
A2 METERING DATA
menu.
Expected Negative
Sequence Current
5 A Unit
14% FLA
28% FLA
7% FLA
, set:
S8 RTD TEMPERATURE MENU
STATOR RTD TYPE: "100 Ohm Platinum" (select desired type)
"Stator" (repeat for RTDs 2 to 12)
RTD #1 APPLICATION:
0.5 j0.866
– +
∠ ) 1000 113° ( ∠ ) )
(EQ 7.3)
menu, set:
menu, set:
CURRENT
Measured Negative
Sequence Current
7–7