Option A, the primary current injection method, is common practice in the field for performing a functional check of CTs due to its simple approach. For verifying highly accurate CTs for metering purpose, e.g. class 0.15 CTs, or transient behavior in protection environment this method is not sufficient as the accuracy of the method and of course the injected current is limited.
Dear Bern Traña, thanks a lot for your interest in this video and for your question. Connecting both HV terminals to ground would cause incorrect measurement results. Connecting both primary terminals to PE has the same effect as a short-circuit in the CT. When connecting the CT for a measurement, on side of the HV side is connected the ground. The side that is able to receive more interferences has to be connected to PE. This is enough to ensure safety, since the impedance between the 2 HV connection is usually very low. To get more information about Current transformer testing please check out the other videos in the following playlist: ua-cam.com/play/PLzmbZeI1bhu-bwtPfgxqAFE-LyK4DzX0h.html Best regards, your OMICRON team
Dear abdullah real, thanks a lot for your interest in our products and videos. Regarding your question: For Oil Type CT’s the regular measurements can be performed with the CTAnalyzer:(omicronenergy.com/ct-analyzer) • Ratio and phase accuracy • Winding resistance • Excitation characteristics (knee points) • Composite error (ALF, ALFi, FS, FSi, Vb) • Burden impedance • Transient CT classes and parameters (TPS, TPX, TPY and TPZ type CTs) • Transient dimensioning factor (Ktd) • If missing/unknown: CT type, class, ratio, knee point, power factor, nominal burden, operating burden, primary and secondary winding resistance • Remanence and residual magnetism For Oil type CT’s, the moisture content and dissipation factor can be determined with our DIRANA (omicronenergy.com/dirana) device. PT’s require a different set of measurements. Please watch these videos to find out more about it: ua-cam.com/video/4L0ch0-Paq8/v-deo.html ua-cam.com/video/eEvIyvewrbY/v-deo.html Best Regards, your OMICRON team
Dear MJ Ilahi, we're really sorry but we can't understand your question, therefor we'd like to ask you to contact us directly. Please find your local contact here: www.omicronenergy.com/en/contact/addresses Best regards, Your OMICRON team
kiran kumar M. Reddy Hello Omicron team, Good explanation..! But I got a question in my mind about variable frequency method used in 50 Hz or 60 Hz designed CTs. Transmission lines reactance wont change. But, the property of the core losses designed for a particular CT core, may vary for different frequencies. (Due to hysteresis losses or eddy current losses). How can this method can calibrate 0.2s class accurately?. ua-cam.com/video/rvsRDsR0ttY/v-deo.html&lc=z131itdryk2pydzzf04cc1erok2cexnphks0k
Dear kiran kumar M. Reddy, Basically you are right. The core losses are frequency depended. The excitation curve and its losses are determined by using different frequencies. In order to obtain correct measurement results, it is necessary to define a model of the transformer which allows a description of the frequency dependent behaviour. With this modelling approach a high accuracy can be achieved. Best regards, Your OMICRON team
Thank you so much, super clear illustration!
Such a nice video sharing about the knowledge of Methods for Current Transformer Testing
Option A, the primary current injection method, is common practice in the field for performing a functional check of CTs due to its simple approach.
For verifying highly accurate CTs for metering purpose, e.g. class 0.15 CTs, or transient behavior in protection environment this method is not sufficient as the accuracy of the method and of course the injected current is limited.
What happens if the HV terminals of CT is short circuited while performing Turn ratio test?
Dear Bern Traña,
thanks a lot for your interest in this video and for your question. Connecting both HV terminals to ground would cause incorrect measurement results. Connecting both primary terminals to PE has the same effect as a short-circuit in the CT. When connecting the CT for a measurement, on side of the HV side is connected the ground. The side that is able to receive more interferences has to be connected to PE. This is enough to ensure safety, since the impedance between the 2 HV connection is usually very low. To get more information about Current transformer testing please check out the other videos in the following playlist: ua-cam.com/play/PLzmbZeI1bhu-bwtPfgxqAFE-LyK4DzX0h.html
Best regards,
your OMICRON team
Please inform me how many type of test need for oil type CT and PT.
Dear abdullah real,
thanks a lot for your interest in our products and videos. Regarding your question:
For Oil Type CT’s the regular measurements can be performed with the CTAnalyzer:(omicronenergy.com/ct-analyzer)
• Ratio and phase accuracy
• Winding resistance
• Excitation characteristics (knee points)
• Composite error (ALF, ALFi, FS, FSi, Vb)
• Burden impedance
• Transient CT classes and parameters (TPS, TPX, TPY and TPZ type CTs)
• Transient dimensioning factor (Ktd)
• If missing/unknown: CT type, class, ratio, knee point, power factor, nominal burden, operating burden, primary and secondary winding resistance
• Remanence and residual magnetism
For Oil type CT’s, the moisture content and dissipation factor can be determined with our DIRANA (omicronenergy.com/dirana) device.
PT’s require a different set of measurements. Please watch these videos to find out more about it: ua-cam.com/video/4L0ch0-Paq8/v-deo.html
ua-cam.com/video/eEvIyvewrbY/v-deo.html
Best Regards,
your OMICRON team
@@omicronenergy Thanks
How to check 50/5 ct trf ....by meter
Dear MJ Ilahi,
we're really sorry but we can't understand your question, therefor we'd like to ask you to contact us directly.
Please find your local contact here: www.omicronenergy.com/en/contact/addresses
Best regards,
Your OMICRON team
kiran kumar M. Reddy
Hello Omicron team,
Good explanation..!
But I got a question in my mind about variable frequency method used in 50 Hz or 60 Hz designed CTs.
Transmission lines reactance wont change.
But, the property of the core losses designed for a particular CT core, may vary for different frequencies. (Due to hysteresis losses or eddy current losses). How can this method can calibrate 0.2s class accurately?.
ua-cam.com/video/rvsRDsR0ttY/v-deo.html&lc=z131itdryk2pydzzf04cc1erok2cexnphks0k
Dear kiran kumar M. Reddy,
Basically you are right. The core losses are frequency depended. The excitation curve and its losses are determined by using different frequencies. In order to obtain correct measurement results, it is necessary to define a model of the transformer which allows a description of the frequency dependent behaviour. With this modelling approach a high accuracy can be achieved.
Best regards,
Your OMICRON team
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