Post on 12-Nov-2014
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Title: Guide for the Application of Rogowski Coils used for Protective Relaying Purposes
Chair: Ljubomir KojovicVice Chair: Veselin Skendzic
Established: January 2004
Assignment - This Guide establishes criteria and requirements for application of Rogowski Coilsused for protective relaying in electric power systems. The selection and application of RCs forthe more common protection schemes are addressed.
Purpose - This document provides a guide for application of Rogowski Coils used for protectiverelaying in electric power systems. It is intended to assist the relay application engineer in thecorrect selection and application of RCs for protective relaying purposes. It provides requirementsrelevant to the performance, operation, testing, safety considerations, and maintenance ofRogowski Coil based current transducers.
This guide applies to all types of Rogowski Coils used for Protective Relaying Purposes.
Volta
ge
Current
Operating pointfor CTs
Saturation voltage
Linear region
Non-Linear region
Operating pointfor voltage transformers
Rogowski Coil V-I Characteristic
Conventional Current Transformer
Rogowski CoilIp Ls
Zbv(t)
MRs
Cs
Low Impedance
High Impedance
∑−=j
j tidtdMtv )]([)(
ip’ Rp Lp LsRs is
im
imr imx
LmRmZb
Rogowski Coil
10
100
1000
0.01 0.1 1 10 100Current [A]
Volta
ge [V
]1200/5 A CT
0 0.05 0.1 0.15 0.2 0.25-15
-10
-5
0
5
10
15
20
25
30
Cur
rent
[kA
]Secondary Current (referred to the primary)
Primary Current
Laboratory Test #346
Time [s]
1200/5 A CT
0 0.02 0.04 0.06 0.08 0.1
Cur
rent
[kA
]
Time [s]
1200/5 A CTsecondarycurrent
Primary current
-20
-10
0
10
20
30
40
-20
-10
0
10
20
0 0.02 0.04 0.06 0.08 0.1
Cur
rent
[kA
]
Time [s]
Rogowski coilnon-integratedsecondary signal Primary current
0 0.02 0.04 0.06 0.08 0.1
-20
-10
0
10
20
30
40
Cur
rent
[kA
]
Time [s]
Rogowski coil non-integratedsecondarysignal
Primary current
0 0.02 0.04 0.06 0.08 0.1
-20
-10
0
10
20
30
40
Cur
rent
[kA
]
Time [s]
Rogowski coil integratedsecondarysignal
Primary current
Intelligent Substations - Hitachi
ConventionalInstrument
Transformers
Low PowerInstrument
Transformers
GCB: gas circuit breakerCT: current transformerPT: potential transformer
Integrated High Voltage Switchgear(circuit breaker, isolator, groundingswitch, current and voltage sensors) inone gas insulated compartment
220 kV
ABB Combi Sensor Up to 60% less space requirement
PASS
Rogowski Electronic Current Transformer applied to a 550 kV Gas Insulated Substation (AREVA)
Trench Electric
Class 0.2 0.5 3P Voltage 6 - 36 kV Ferroresonance free
Cooper Power Systems
Differential Protection of
90 MVA, 34.5/1 kV EAF Transformers
26 in
9 in
Scale ±7.5 kApeak
Scale ±300 kApeak
Operate Signals Mismatch between primary and secondary currents is less than 1%
Trip Signals
95 kApeak
Restraint Signals
Primary Currents
Secondary Currents
A-phaseB-phaseC-phase
Cooper Power SystemsMobile Substations (primary side RCs)
Mobile Substations (secondary side RCs)
ABC
Ia Ib Ic Ir
Protective Relay
I1 I2
I1 I2
Protective Relay
Transformeror
Generator
i(t)
Rogowski Coil
filters andA/D
powersupply
Rogowski coil Conventional CT
E/O
O/E reception andinterface to relays
ground level
HV levelfiber opticalcable
Rogowski coil
Fiber OpticalCable
A/D
DataPower
Converter
LaserDiode
DataReceiver
PowerSupply
D/AConverter
DSP
AnalogOutput
DigitalOutput
RemoteUnit
GroundUnit
Fiber-OpticalCables
HV Linei(t)
GroundUnit
RC andRemote
Unit
Remote Unit
RC
Power DataFiber-Optical Cables
Ground Unit Junction
Box
HV Potential
Photonic Power Systems, Inc.