96 6LE008146B
Measurement functions
6.11 Accuracy of measurements
The hw+ circuit breaker equipped with the sentinel Energy trip unit and embedded sensors
is defined as a PMD-DD measurement device of accuracy class 1 on power and energy
measurements in accordance with the IEC 61557-12 version 2 standard.
This standard classifies PMD devices according to the measurements available in Table 1
below extracted from the IEC 61557-12 version 2 standard: "Functional classification of PMDs
with the minimum functions required".
Table 1
Symbol of functions
(a)
Type of PMD (b)
PMD-I
Energy eciency
PMD- II
Basic monitoring of
the installation
PMD-III
Advanced
monitoring of the
installation/network
performance
P
■ ■
Q
■ ■
S
■ ■
E
a
■ ■ ■
E
r
■ ■
E
ap
■
f
■ ■
I
■ ■
I
n
■
U and/or V
■ ■
PF
■ ■
THD
u
and/or THD
v
and/or THD-R
u
and/or
THD-R
v
■
THD
i
and/or THD-R
i
■
(a) Only the total variables are mandatory.
(b) For PMDs other than PMD-I, PMD-III and those called PMP-x, other combinations of
functions are authorised and must be specified by the manufacturer.
The hw+ circuit breaker with sentinel Energy trip unit is classified PMD-II or PMD-III according
to the rating plug installed.
Rating plug type PMD- II device PMD- III device
Standard
■
Meter Plus
■
Harmonic
■
Advanced
■
Ultimate
■