7.10
SEL-734 Meter Instruction Manual Date Code 20090730
Time-Synchronized Measurements
Power Flow Analysis
Use Equation 7.2 to calculate the generation supplied from Substation S and
Substation R, plus the load at Substation T shown in Figure 7.3.
Equation 7.2
The complex power generation supplied by Substation S is:
Equation 7.3
The complex power generation supplied by Substation R is:
Equation 7.4
The load at Substation T supplied by Substation S is:
Equation 7.5
The load at Substation T supplied by Substation R is:
Equation 7.6
The total load at Substation T is:
Equation 7.7
Meter at Substation T Looking Towards Substation R
V
AT – R
295.603 kV ∠1.6 I
AT– R
234.036 A ∠135.8
V
BT–R
295.603 kV ∠238.4 I
BT–R
234.036 A ∠15.8
V
CT–R
295.603 kV ∠118.4 I
CT–R
234.036 A ∠104.2
where:
S
3ø
= Three-phase complex power (MVA)
P
3ø
= Three-phase real power (MW)
Q
3ø
= Three-phase imaginary power (MVAR)
V
pp
= Phase-to-phase voltage
V
p
= Phase-to-neutral voltage
I
*
L
= Complex conjugate of the line current
Table 7.8 Meter Voltage and Current Measurement (Sheet 2 of 2)
Voltage Current
S
3ø
P
3ø
jQ
3ø
+=
3V
pp
I
*
L
• • =
3V
p
I
*
L
• • =
S
S
3 288.675 kV 0°∠• ()238.995 A 41.9– °∠()• =
154.1 MW – j138.2 MVAR=
S
R
3 303.109 kV 0.2– °∠• ()234.036 A 44.2°∠()• =
152.6 MW + j148.3 MVAR=
S
TS–
3 295.603 kV 1.6– °∠• ()238.995 A 135.8°∠()• =
153.7 MW + j145.9 MVAR=
S
TR–
3 295.603 kV 1.6– °∠• ()234.036 A 135.8– °∠()• =
152.8 MW – j140.5 MVAR–=
S
T
S
TS–
S
TR–
+=
306.5 MW– j5.4 MVAR+=
Courtesy of NationalSwitchgear.com
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