hager h3+, Communication Instruction Manual

Page: 48 / 127

48
6LE005550A
Function of the Energy trip unit
3.3 Measurement function
Details about the calculations
The calculations of these powers take into account the harmonics up to rank 31.
Symbol Definition
N Total number of samples per network period
T Period measured, in seconds
k sample number of phase p current
k sample number of voltage between phase p and neutral
Phase difference between the current and the voltage for phase p
Rank i harmonic component
Sampling involves taking samples at regular intervals of the instantaneous values of
the current and voltage analogue signals. The digitisation of the electrical variables
performed by the Energy trip unit results in a set of discrete values all synchronised
in relation to each other. This method also makes it possible to take into account the
dephasing between the voltage and the current (cos φ ).
Power sign
The power values are signed.
The 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 performed from the HTD210H panel display or the
HTP610H configuration tool (see § 3.3.10).
The active power is given with the + sign when it is "delivered", i.e. when the
equipment is working as a receiver.
The active power is given with the - sign when it is "received", i.e. when the
equipment is working as a generator.
The reactive power is given with the same sign as the active energy and power,
when the current lags the voltage, i.e. when the equipment is inductive.
The reactive power is given with the opposite sign to the active energy and power,
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.
P < 0 P > 0
Q > 0
Ii
Capacitive
(advance)
I Inductive (delay)
Q < 0
III Inductive (delay) IV
Capacitive
(advance)