Definition Of The Active Power Measurement - Siemens Siprotec 7UM62 Manual

A Appendix
A.6

Definition of the Active Power Measurement

502
The 7UM62 used the generator reference-arrow system. The power output is posi-
tive.
I
G
Figure A-44 Definition of Positive Direction of Reference Arrows
Table A-2 shows the operating ranges for synchronous and asynchronous machines.
Parameter 1108 ACTIVE POWER is set to Generator. "Normal condition" shows the
active power under normal operating conditions: + means that a positive power is dis-
played on the protective device, – that the power is negative.
Table A-2 Operating Ranges for Synchronous and Asynchronous Machines
Synchronous Generator
+P
Stability
U
limit
ϕ
underexcited overexcited
Reactive power Q is controlled by the ex-
citation,
Normal condition: +P and +Q
Asynchronous Generator
P
P
BREAK
I
Reactive power is drawn from the sys-
tem to maintain the excitation;
Normal condition: +P and –Q
U
I
Stability
+Q
limit
Reactive power Q is controlled by the ex-
citation,
Normal condition: –P and +Q
+P
U
ϕ
+Q
The motor draws both active and reac-
tive power from the system;
Normal condition: –P and –Q
Synchronous Motor
+P
U
ϕ
underexcited overexcited
I
Asynchronous Motor
U
ϕ
I
P
P
BREAK
7UM62 Manual
C53000-G1176-C149-3
+Q
+P
+Q