ABB eVD4, Installation And Service Instructions Manual, Page: 16 / 72

14 14
u
out
=
u
p
C
1
C
1
+ C
2
U
out
U
p
General diagram of the capacitive divider (voltage sensor).
The extent of error “
ε
” made by the Rogowski current sensors
is constant and independent of the primary current value.
This means the error can be eliminated with an appropriate
characteristic correction factor of the sensor. Traditional
current transformers have an error which depends on the
primary current. For this reason, the error committed is not
constant so cannot be corrected and, furthermore, takes on
substantial values at the extremities of the primary current
application range.
Since they are fully integrated and tested in the factory,
the eVD4 circuit-breakers take advantage of this concept
to obtain an excellent measurement performance. During
production of each eVD4 the RBX615 is calibrated with the
characteristic correction factors of the current and voltage
sensors mounted on that particular circuit-breaker.
5.3.6.2 Capacitive divider
The capacitive element is made up of a cylindrical metal
surface, facing the circuit-breaker bushing. The output signal
is a voltage directly proportional to the primary voltage.
The voltage sensors are characterized by absence of any
ferroresonance phenomena and their insensitivity to the
effects of the direct components. A single divider covers
the service range of voltages up to the rated voltage of the
circuit-breaker.
5.3.6.3 Types and characteristics of the sensors used in
the eVD4 circuit-breaker
eVD4 circuit-breakers, which do not include voltage
measurement, use KEVCR AC1 and KEVCR BC1 current
sensors with rated currents of 1250, 2000 and 2500 A
respectively.
KEVCR AA1 and KEVCR BA1 type sensors are used for the
eVD4 with voltage measurement.
Sensor voltage accuracy voltage data current accuracy current data
K1
COMBISENSOR KEVCR 17.5 AA1 Kn 10000: 1 cl: 1/3P Ku 1.9/8h Ipr: 250A cl: 1/5P Usr: 0.150/0.180V
CURRENT SENSOR KEVCR 17.5 AC1 – – – Ipr: 250A cl: 1/5P Usr: 0.150/0.180V
K2
COMBISENSOR KEVCR 17.5 BA1 Kn 10000: 1 cl: 1/3P Ku 1.9/8h Ipr: 500A cl: 1/5P Usr: 0.150/0.180V
CURRENT SENSOR KEVCR 17.5 BC1 – – – Ipr: 500A cl: 1/5P Usr: 0.150/0.180V
K3
COMBISENSOR KEVCR 17.5 CA1 Kn 10000: 1 cl: 1/3P Ku 1.9/8h Ipr: 500A cl: 1/5P Usr: 0.150/0.180V
CURRENT SENSOR KEVCR 17.5 CC1 – – – Ipr: 500A cl: 1/5P Usr: 0.150/0.180V