GE N60 Instruction Manual page 380

METERING
DELTA-connected instrument transformers
• ABC phase rotation:
V_0 =
V_1 =
V_2 =
The zero-sequence voltage is not measurable under the Delta connection of instrument transformers and is defaulted to
zero. The table below shows an example of symmetrical components calculations for the ABC phase rotation.
Table 6-1: Symmetrical components calculation example
SYSTEM VOLTAGES, sec. V *
V V
AG BG
13.9 76.2
0° –125°
UNKNOWN (only V
1
can be determined)
* The power system voltages are phase-referenced – for simplicity – to V
relative matter. It is important to remember that the UR displays are always referenced as specified under
SYSTEM SETUP  POWER SYSTEM  FREQUENCY AND PHASE REFERENCE
The example above is illustrated in the following figure.
6
6-14
N/A
 
1 30
– 2
 
------------------ V + aV + a V
AB BC CA
3 3

1 30
2
 
--------------- V + a V + aV
AB BC CA
3 3
V V V
CG AB BC
79.7 84.9 138.3
–250° –313° –97°
and V 84.9 138.3
2
0° –144°
Figure 6-3: Measurement convention for symmetrical components
SYSTEM VOLTAGES
A
A
N60 NETWORK STABILITY AND SYNCHROPHASOR MEASUREMENT SYSTEM – INSTRUCTION MANUAL
• ACB phase rotation:
V_0 =
V_1 =
V_2 =
VT conn. relay INPUTS, sec. V
V F5ac F6ac
CA
85.4 WYE 13.9 76.2
–241° 0° –125°
85.4 DELTA 84.9 138.3
–288° 0° –144°
and V
AG
.
WYE VTs
DE TA VTs
CHAPTER 6: ACTUAL VALUES
N/A

1 30
2
 
--------------- V + a V + aV
AB BC CA
3 3
 
1 30
2
–
 
------------------ V + aV + a V
AB BC CA
3 3
SYMM. COMP, sec. V
F7ac V V
0 1
79.7 19.5 56.5
–250° –192° –7°
85.4 N/A 56.5
–288° –54°
, respectively. This, however, is a
AB
SETTINGS 
SYMMETRICAL
COMPONENTS
1
0
2
1
2
827844A1.CDR
V
2
23.3
–187°
23.3
–234°