1. Sensor presentation

2. Product Scope
A Sensor is a device intended to transmit a signal corresponding to the primary current or voltage to the secondary equipment.
PowerIT Sensors are typically used in MV switchgears and outdoor switches for measuring, protection and indication.

3. Sensors vs. Instrument Transformers
. . . but not in transformers!
Trends in electrical engineering
Size
Performance
Standardisation

4. Sensors vs. Instrument Transformers
Reason: The properties of material used
Saturation
Unlinear range
Linear range
Unlinear range
Remedy: Absence of iron

5. Rogowski coil First published in1912 by Rogowski and Steinhous
Passive element
Uniformly wound coil with non-magnetic core
Output signal is proportional to the derivate of primary current
IEC
Distribute the coil
Note the missing of turn wire to eliminate disturbance

6. Requirements for a Current Sensor
IEC-requirements
Cost effective
Low LCA
Size
Rogowski
What is the requirment -> it should work
New technic -> Better than the old
ABB started to look into new technologies in 1990
IEC: ABB involved in taking up the new standard
Cost Effective:
Standardisation
Cost savings for end customer (user friendly)
reliable
Easy to make/logistics

7. Sensors vs. Instrument Transformers
Rated primary current (CT) 
Ip (log)
Ipr=80 A

8. Sensors vs. Instrument Transformers
Rated primary current range (sensor) 
Ip (log)
Ipr = 40 A A A

9. Sensors vs. Instrument Transformers
Accuracy limit factor (Kalf) c
Protection class 10P CS
Ip (log) CT
Ipr

10. Voltage Divider IEC 60044-7 Resistive divider Matched resistor pair
1: divider ratio
Accuracy up to class 0.2
Capacitive divider
Zc = 1/C
1: divider ratio
Accuracy up to class 3
Small size ideal for bushings
IEC
Cast in type, gas insulated
10 meters due to capasitances -> phase error

11. Requirements of a Voltage Sensor
IEC-requirements
Cost effective
Safe
Low LCA
Size
Resistive Voltage divider
IEC = Electronic voltage transformers
Cost effective, if no space is forceen in the switchgear special VT’s must be used
Safe = VT faults very common
Size = can be integrated
Capacitive Voltage divider

12. Sensors vs. Instrument Transformers
Linearity
Typical error, sensor

13. Sensors vs. Instrument Transformers
Transmitted signal level
Voltage transformer (ku=1,9) Voltage sensor
1, V, 25 VA mV, mVA
At free potential, must be earthed Always earthed in the sensor
Secondary losses = I2R Secondary losses negligible
Current transformer (Kalf =20) Current sensor
0, A, 5 VA 7, mV, mVA
At free potential, must be earthed At free potential

14. Sensors vs. Instrument Transformers
Short-circuited secondary (VT)
Voltage transformer Voltage sensor
250 M
Isc
Isc
25 k
Isc/Acu = 160 A/mm2
Temp C
Explosion within 30 s
Isc = Inormal

15. Sensors vs. Instrument Transformers
Open secondary (CT)
Current transformer Current sensor
Isc
Uopen kV
Isc/Acu = 40 mA/mm2

16. Sensors vs. Instrument Transformers
Frequency response
rel CT 10
100
1000
10 000
F/Hz VS
(Res.) VT CS VS
(Cap.)

17. Sensors vs. Instrument Transformers
Secondary wiring
Terminal blocks
Instr. transf.
Relay
Wiring and screw connections
Testing of connections
Sensor
IED
Integrated cable
and connector

18. Sensors
Secondary wiring
II,
Shielding
Sensor
IED S1 S2

19. Sensors vs. Instrument Transformers
Compactness
Current transformers Combisensor
Voltage transformer
Size of active parts
Number of cores

20. Sensor Technology - CT/VT vs. Sensors

21. Standards for Sensors
Sensors from ABB are designed, manufactured and tested
according to international standards when applicable. n
Voltage sensors :
IEC ( ) n
Instrument transformers – n
Part 7: Electronic voltage transformers n
Current sensors :
IEC
( ) n
Instrument transformers – n
Part 8: Electrical current transducers n
Combisensors :
IEC ( ) n
Instrument transformers – n
Part 3: Combined transformers

22. Combi Sensor, type KEVCD_
Current and voltage sensors in the same block
Measurement and protection by one sensor
Dimensions and primary connections same as DIN-type CTs (DIN 42600)
12, 17.5, 24 kV, two types:
A. </= 1250 A
B. > 1250 A (max A)
Including coupling electrode for voltage indication

23. Selection Guide for KEVCD Sensors

24. Sensor Concept

25. Sensors in use around the world
In use in 56 countries
More than sensors in operation

26. Sensors in use around the world

27. Sensors
Safety
Short delivery time
Smart integration