scholarly journals Toward the Standardization of Limits to Offset and Noise in Electronic Instrument Transformers

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 4061
Author(s):  
Alessandro Mingotti ◽  
Lorenzo Peretto ◽  
Roberto Tinarelli
Keyword(s):  
Low Power ◽  
Mathematical Approach ◽  
Electronic Instrument ◽  
Critical Aspect ◽  
Correct Operation ◽  
Ratio Error ◽  
Instrument Transformers

The scenario of instrument transformers has radically changed from the introduction of the Low-Power version, both passive and active. The latter type, typically referred to as Electronic Instrument Transformers (EITs), has no dedicated standard within the IEC 61869 series yet. To this purpose, in the authors’ opinion, it is worth understanding how the limits of typical disturbances affecting EITs should be standardized. In particular, after a brief review of the standards, the work presented a mathematical approach to determine the sources of signal disturbances influence, which affect the rms value, on the ratio error. From the results, we discussed that the emergence of disturbances generated within the EIT is a critical aspect to be studied with data of typical off-the-shelf devices. Therefore, to guarantee a correct operation of the devices, a proper standardization of the sources of disturbance should be provided.

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 On the Long-Period Accuracy Behavior of Inductive and Low-Power Instrument Transformers

Sensors ◽  
2020 ◽  
Vol 20 (20) ◽  
pp. 5810
Author(s):  
Alessandro Mingotti ◽  
Lorenzo Bartolomei ◽  
Lorenzo Peretto ◽  
Roberto Tinarelli
Keyword(s):  
Low Power ◽  
Accuracy Evaluation ◽  
Power Network ◽  
Critical Aspect ◽  
Long Period ◽  
Instrument Transformers ◽  
Instrument Transformer ◽  
Control And Management

The accuracy evaluation of instrument transformers is always a key task when proper control and management of the power network is required. In particular, accuracy becomes a critical aspect when the grid or the instrumentation itself is operating at conditions different from the rated ones. However, before focusing on the above non-rated conditions, it is important to fully understand the instrument transformer behavior at rated conditions. To this end, this work analyzed the accuracy behavior of legacy, inductive, and low-power voltage transformers over long periods of time. The aim was to find patterns and correlations that may be of help during the modelling or the output prediction of voltage transformers. From the results, the main differences between low-power and inductive voltage transformers were pointed out and described in detail.

scholarly journals Optimised calibration programmes for comparators for instrument transformers

2021 ◽  
Vol 88 (2) ◽  
pp. 122-131
Author(s):  
Christian Mester
Keyword(s):  
Experimental Study ◽  
Operating Principle ◽  
Device Under Test ◽  
Operating Range ◽  
Ratio Error ◽  
Phase Displacement ◽  
Instrument Transformers ◽  
Instrument Transformer ◽  
Method Of Measurement

Abstract Traditionally, instrument transformers are calibrated using bridges. By definition, bridges use the null method of measurement. The traditional calibration programme for instrument transformer bridges characterise namely this null measurement. Many new commercial comparators for instrument transformer use a very different method. They sample the secondary signals of reference and device under test (dut) transformer independently. Based on the samples, magnitude and phase of both signals are determined. Ratio error and phase displacement are calculated. Consequently, the significance of their calibration using the traditional calibration programme is limited. Moreover, the operating range of modern comparators is much larger than that of bridges. The additional versatility cannot be used without an adapted calibration programme. This article analyses the calibration programmes for both technologies. An experimental study confirms both the suitability of the new calibration programme and the need to chose the calibration programme depending on the technology of the device to be calibrated. The conclusion is very general and applies to all measurement problems where an operating principle is replaced by another – when changing the operating principle, it is important to check the calibration programme and adapt it if necessary.

Simulation Model for Assessing Operational Performance of Current Transformers

2007 ◽  
Vol 18-19 ◽  
pp. 71-77
Author(s):  
I. Sule
Keyword(s):  
Simulation Model ◽  
Current Transformer ◽  
Operational Performance ◽  
Current Transformers ◽  
Correct Operation ◽  
Operational Conditions ◽  
Secondary Current ◽  
Protection Scheme ◽  
The Core ◽  
Instrument Transformers

In determining the correct operation of relays of a protection scheme, proper representation of instrument transformers and their behavior in conditions where there can be saturation, is very critical. The main objective of this paper is to develop simulation model for assessing the operational performance of Current Transformer (CT). In order to test the validity of the developed model, three cases of CT operational conditions were considered, with data collected from Gombe, 330/132/33kV PHCN substation. The simulation results revealed various configuration performance responses that could affect relay protective schemes to different degrees. The CT responses revealed that the secondary current and voltage were distorted when the core flux linkages exceeded the set 9.2 pu saturation limit. It is concluded that the model developed for the CT of interest yield satisfactory results.

scholarly journals A New Online Temperature Compensation Technique for Electronic Instrument Transformers

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 97614-97623 ◽  
Author(s):  
Zhenhua Li ◽  
Yawei Du ◽  
A. Abu-Siada ◽  
Zhenxing Li ◽  
Tao Zhang
Keyword(s):  
Temperature Compensation ◽  
Electronic Instrument ◽  
Instrument Transformers ◽  
Compensation Technique

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.

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