Calibration system and uncertainty budget for instrument transformers with digital output

1999 ◽  
Author(s):  
J.I. Juvik
Keyword(s):  
Uncertainty Budget ◽  
Calibration System ◽  
Digital Output ◽  
Instrument Transformers

High-accuracy online calibration system for electronic voltage transformers with digital output

2014 ◽  
Vol 36 (6) ◽  
pp. 734-742 ◽  
Author(s):  
Zhenhua Li ◽  
Hongbin Li ◽  
Zhi Zhang ◽  
Pandian Luo ◽  
Hongfeng Li ◽  
...  
Keyword(s):  
High Accuracy ◽  
Calibration System ◽  
Digital Output ◽  
Online Calibration

An On-Site Calibration System for Electronic Instrument Transformers Based on Labview

2014 ◽  
Vol 21 (2) ◽  
pp. 257-270 ◽  
Author(s):  
Ming Zhang ◽  
Kaicheng Li ◽  
Jun Wang ◽  
Shunfan He
Keyword(s):  
Dynamic Range ◽  
Current Transformer ◽  
Data Synchronization ◽  
Electronic Instrument ◽  
Calibration System ◽  
Adaptive Communication ◽  
Electronic Current ◽  
Instrument Transformers ◽  
Error Correction Algorithm ◽  
Electronic Current Transformers

Abstract Electronic voltage transformers (EVT) and electronic current transformers (ECT) are important instruments in a digital substation. For simple, rapid and convenient development, the paper proposed an on-site calibration system for electronic instrument transformers based on LabVIEW. In the system, analog signal sampling precision and dynamic range are guaranteed by the Agilent 3458A digital multimeter, and data synchronization is also achieved based on a self-developed PCI synchronization card. To improve the measurement accuracy, an error correction algorithm based on the Hanning window interpolation FFT has good suppression of frequency fluctuation and inter-harmonics interference. The human-computer interface and analysis algorithm are designed based on LabVIEW, and the adaptive communication technology is designed based on IEC61850 9-1/2. The calibration system can take into account pairs of digital output and analog output of the electronic voltage/current transformer calibration. The results of system tests show that the calibration system can meet the requirements of 0.2 class calibration accuracy, and the actual type test and on-site calibration also show that the system is easy to operate with convenience and satisfactory stability.

scholarly journals Test equipment and its effect on the calibration of instrument transformers

2018 ◽  
Vol 7 (1) ◽  
pp. 339-347
Author(s):  
Enrico Mohns ◽  
Peter Räther
Keyword(s):  
Uncertainty Budget ◽  
Current Transformer ◽  
National Standards ◽  
Test Equipment ◽  
Management Systems ◽  
Testing Instrument ◽  
Quality Management Systems ◽  
Ratio Error ◽  
Instrument Transformers ◽  
A Current

Abstract. State-approved test centres in Germany supplying accuracy tests for instrument transformers must, in the future, provide measurement uncertainty budgets for their quality management systems. In this work, the cause of ratio error and phase displacement of instrument transformers are therefore discussed. The traceability to the national standards of PTB, the attainable uncertainty, and the permitted error limits of test equipment for testing instrument transformers are presented. Finally, an example of an uncertainty budget for a current transformer of the class 0,2 S is given.

Highly Accurate Calibration System for Electronic Instrument Transformers

2011 ◽  
Vol 18 (2) ◽  
pp. 315-322 ◽  
Author(s):  
Yue Tong ◽  
Guoxiong Ye ◽  
Keqin Guo ◽  
Hongbin Li
Keyword(s):  
Low Cost ◽  
Phase Error ◽  
Electronic Instrument ◽  
Calibration System ◽  
Ratio Error ◽  
Asynchronous Sampling ◽  
Instrument Transformers ◽  
Convolution Window ◽  
Instrument Transformer ◽  
Electronic Current Transformers

Highly Accurate Calibration System for Electronic Instrument Transformers A high accurate electronic instrument transformer calibration system is introduced in this paper. The system uses the fourth-order convolution window algorithm for the error calculation method. Compared with Fast Fourier Transform, which is recommended by standard IEC-60044-8 (Electronic current transformers), it has higher accuracy. The relative measuring errors caused by asynchronous sampling could be reduced effectively without any special hardware technique adopted. The results show that the ratio error caused by asynchronous sampling can be reduced to 10-4, and the phase error can be reduced to 10-3 degrees when the deviation of frequency is within ±0.5 Hz. The present method of measurement processing is achieved by a high-accuracy USB multifunction data acquisition (DAQ) card and virtual measurement devices, with low cost, short exploitation period and high stability.

scholarly journals Calibration of a Digital Current Transformer Measuring Bridge: Metrological Challenges and Uncertainty Contributions

Metrology ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 93-106
Author(s):  
Guglielmo Frigo ◽  
Marco Agustoni
Keyword(s):  
Ad Hoc ◽  
Uncertainty Budget ◽  
Current Transformer ◽  
Point Of View ◽  
Generation Process ◽  
Main Challenge ◽  
Instrument Transformers ◽  
Conventional Instrument ◽  
Technical Specifications ◽  
Commercial Device

In this paper, we consider the calibration of measuring bridges for non-conventional instrument transformers with digital output. In this context, the main challenge is represented by the necessity of synchronization between analog and digital outputs. To this end, we propose a measurement setup that allows for monitoring and quantifying the main quantities of interest. A possible laboratory implementation is presented and the main sources of uncertainty are discussed. From a metrological point of view, technical specifications and statistical analysis are employed to draw up a rigorous uncertainty budget of the calibration setup. An experimental validation is also provided through the thorough characterization of the measurement accuracy of a commercial device in use at METAS laboratories. The proposed analysis proves how the calibration of measuring bridges for non-conventional instrument transformers requires ad hoc measurement setups and identifies possible space for improvement, particularly in terms of outputs’ synchronization and flexibility of the generation process.

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