IEC 61869-2 Influences of the new standard on testing with the CT Analyzer
IEC 61869-2 The new standard for current transformer testing The IEC 61869-2 standard (Instrument transformers – Part 2: Additional requirements for current transformers) combines two former standards: > IEC 60044-1 Instrument transformers – Part 1: Current transformers > IEC 60044-6 Instrument transformers – Part 6: Requirements for protective current transformers for transient performance This revision was initiated to reflect the technological advances and improvements in and around current transformers and their field of application. The CT Analyzer incorporates this standard in the new software version 4.30.
“ T hi s ov er v i ew i nc l ud e s t he mo st i m po r t ant new f eat ur e s w i t h r e s pec t t o t he u se of t he C T Anal y z er t o t e st t o t he I E C 6 18 69 - 2 st and ar d .” Mar kus Jäger , C T A
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naly zer Pr oduc t M
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An overview of the changes Method for calculating the transient dimensioning factor A revised method for calculating the transient dimensioning factor (Ktd) now also takes into account the latest protective devices, which can detect and react to faults more quickly. For automatic reclosure (AR), special attention was focused on the transformer‘s saturation behavior and to remanence decay.
A more precise calculation of the current transformer‘s transient response in the overall system can contribute to significant optimization of the dimensioning. The size advantage resulting from this not only offers direct cost advantages for the transformer itself, it also simplifies deployments at locations where space is at a premium, for example, in gas-insulated switchgear (GIS).
IEC 61869-2 Ktd curve K
9 8
Ktfp,Max
7 6 5 4
Ktf,Max
3 2 1 ttf,Max 0s
KtfMax
ttfp,Max 0.05 s
0.1 s
0.15 s
Ktfp
Ktd 0.2 s t
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IEC 60044-1 standard
Extended load range for all measurement classes The optional extendable load range up to 1 VA can be applied to all measurement classes with the new standard. This results in greater consideration of the digital systems used, which present lower loads when compared with analog systems.
IEC 61869-2 standard
Class 0.1
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Class 0.2
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Class 0.2S
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■
Class 0.5
–
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Class 0.5S
–
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Class 1
–
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Class 3
–
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Class 5
–
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Uniform measurement definitions IEC 60044-1 IEC 60044-6 IEC 61869-2 Axis standard standard standard
When recording the magnetization curve, RMS or peak values were measured, depending on the standard used. The new IEC 61869-2 standard combines these measurement definitions. As such, measurements are now easier to perform and the risk of faults due to confusion has been reduced.
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x
RMS (Ie)
Peak (Ie)
y
RMS (Uct )
Avg. cal. in Avg. cal. in RMS (E.M.F.) RMS (E.M.F.)
RMS (Ie)
New definition of the maximum saturation flow In the previous definition, the maximum saturation flow Ψsat was defined by the transition from the unsaturated to the saturated area of the magnetization characteristic curve.
Ψ Ψsat
Ie
The new IEC 61869-2 standard now redefines this value shifting the reference into the saturated area. The saturation flow value, which was previously defined as too low, has therefore been corrected.
P1
Ip
Np:Ns
S1 Ie
Alternative measurement method
IXm
The new standard defines an alternative method for measuring the ratio error in compliance with the measuring principle employed by the CT Analyzer.
RCT IRm
Xm
Rb
Rm
E.M.F. E0
P2
In contrast to the direct method, this reduces the measurement time and the measuring technology required. As a result, it greatly simplifies routine measurements performed during production and maintenance work in the field.
Ip •
Np = Is + Ie Ns Ie
Us
Is
E.M.F.
θ
φs
Ie Im IXm
6
Us Xb
S2
Re Is • RCT
Is
IRm
Ip
Working with the new standard 1
New software version You can download the new software version for the CT Analyzer free-of-charge in the Customer Area at www.omicron.at. A detailed description of the installation process and further details on taking measurements with the CT Analyzer in line with the new standard can be found in the CT Analyzer user manual.
OMICRON Customer Area
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CT Analyzer user manual
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Activating the standard on the CT Analyzer Once the latest version of the CT Analyzer software has been downloaded, you can activate the new IEC 61869-2 standard in the menu.
Activating the standard
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© OMICRON L2107, November 2012 Subject to change without notice.
