876LE008146B
Measurement functions
6.5 Measuring power
The sentinel Energy trip unit continuously calculates the power variables based on current and
voltage measurement samples. The variables calculated are:
- the active powers (total Ptot and per phase)
- the reactive powers (total Qtot and per phase)
- the apparent powers (total Stot and per phase) in kVA
- the maximum and minimum values for each of these powers
- the cos and power factors (total values and per phase)
- the operating quadrant and the type of load (capacitive or inductive).
Power sign
The power values are signed.
The sentinel Energy circuit breaker can be supplied both from the top and from the bottom. It
is therefore important to configure the power value sign in line with the supply direction. This
configuration is done from the sentinel Energy display, the panel display or the Hager Power
setup software.
The active powers are given with the + sign when they are imported (consumed), i.e. when the
equipment is working as a receiver.
The active powers are given with the - sign when they are exported (produced), i.e. when the
equipment is working as a generator.
The reactive powers are given with the same sign as the active energies and powers, when the
current lags the voltage, i.e. when the equipment is inductive.
The reactive powers are given with the opposite sign to the active energies and powers, when
the current is ahead of the voltage, i.e. when the equipment is capacitive.
The operating quadrant (I, II, III, IV) is therefore given according to the power sign.
Direction of power supply Operating quadrant
Positive
Supply from
the top
Negative
Supply from
the bottom
Q (+)
Ea- Ea+
Er-
-P
(+kvar)
-Q
Er +
P (-)
P (-) P (+)
Q (-) Q (-)
S
S
S
Q (+)
P (-)
S
Inductive
Power produced
Power produced
Power consumption
Power consumption
Inductive
Capacitive
Capacitive
quadrant II
quadrant III
quadrant I
quadrant IV
To Next Page
Loading...
Need help?
General
