Evaluation of Low-Power Instrument Transformers for Generator Differential Protection

2018 ◽  
Vol 33 (3) ◽  
pp. 1143-1152 ◽  
Author(s):  
Michel Normandeau ◽  
Jean Mahseredjian
Keyword(s):  
Low Power ◽  
Differential Protection ◽  
Instrument Transformers

Transformer Differential Protection Using Process Bus According to IEC 61850-9-2 and Non-Conventional Instrument Transformers

2015 ◽  
Vol 799-800 ◽  
pp. 1311-1315
Author(s):  
G. Igarashi ◽  
J.C. Santos
Keyword(s):  
Time Synchronization ◽  
Power Transformers ◽  
Response Analysis ◽  
Differential Protection ◽  
Iec 61850 ◽  
Instrument Transformers ◽  
Synchronization Signal ◽  
Conventional Instrument ◽  
Transformer Differential Protection

Our aim is to show some impacts on the differential protection of power transformers when using Non-Conventional Instrument Transformers associated with the IEC 61850-9-2 process bus. Described herein are a model for simulating the samples in the process bus, a proposed algorithm for differential protection of power transformers adapted from conventional differential relays so that it works according to the IEC 61850-9-2 standard, and a response analysis of the protection algorithm with the loss of the time synchronization signal in the process bus. Suggestions on parameters to be followed for safer operation of the process bus in these circumstances are also offered.

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.

scholarly journals Why Should We Test the Wideband Transformation Accuracy of Medium Voltage Inductive Voltage Transformers?

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4432
Author(s):  
Michal Kaczmarek ◽  
Ernest Stano
Keyword(s):  
Low Power ◽  
Magnetic Core ◽  
Sinusoidal Voltage ◽  
Higher Harmonics ◽  
Medium Voltage ◽  
Phase Displacement ◽  
Secondary Voltage ◽  
Instrument Transformers ◽  
Multiple Frequencies ◽  
Limiting Values

In this paper the results of the tests of the wideband transformation accuracy of medium voltage (MV) inductive voltage transformers (VTs) in the frequencies range from 50 Hz up to 5 kHz are presented. The values of voltage error and phase displacement for transformation of the harmonics of distorted primary voltages are determined. In the case of a typical 50 Hz-type inductive VT with a rated primary voltage equal to (15/Ö3) kV and (20/Ö3) kV manufactured by an international company the limiting values of the accuracy classes extension for quality metering required by the standard IEC 61869-6 for the Low Power Instrument Transformers (LPIT) were not exceeded. While, in the same test other MV inductive VTs show poor accuracy and even resonance at multiple frequencies. Unfortunately, this problem also arises from nonlinearity of the magnetization characteristic of their magnetic core. Therefore, for transformation of the sinusoidal voltage in the secondary voltage significant but not easily detectable values of the low order higher harmonics are present. Moreover, for transformation of harmonics of distorted primary voltage the influence of connected capacitance on the obtained values of voltage error and phase displacement was tested.

scholarly journals Smart Characterization of Rogowski Coils by Using a Synthetized Signal

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3359 ◽  
Author(s):  
Alessandro Mingotti ◽  
Lorenzo Peretto ◽  
Roberto Tinarelli
Keyword(s):  
Low Power ◽  
Distribution System ◽  
Network Models ◽  
Experimental Tests ◽  
Current Transformer ◽  
Rogowski Coil ◽  
Sufficient Information ◽  
Instrument Transformers ◽  
Rogowski Coils ◽  
Characterization Procedure

With the spread of new Low-Power Instrument Transformers (LPITs), it is fundamental to provide models and characterization procedures to estimate and even predict the LPITs’ behavior. In fact, distribution system operators and designers of network models are looking for all forms of information which may help the management and the control of power networks. For this purpose, the paper wants to contribute to the scientific community presenting a smart characterization procedure which easily provides sufficient information to predict the output signal of a Low-Power Current Transformer (LPCT), the Rogowski coil. The presented procedure is based on a synthetized signal applied to the Rogowski coil. Afterwards, the validity of the procedure is assessed within the Matlab environment and then by applying it on three off-the-shelf Rogowski coils. Simulations and experimental tests and results involving a variety of distorted signals in the power quality frequency range and by adopting a quite simple measurement setup demonstrated the effectiveness and the capability of the procedure to correctly estimate the output of the tested device.

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.

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