Differential protection methodology for arbitrary three-phase power transformers

2008 ◽  
Author(s):  
Z. Gajic
Keyword(s):  
Power Transformers ◽  
Differential Protection ◽  
Three Phase

scholarly journals Designing A Protective Relay for Differential Protection of Power Transformers Using Clarks Transform and S Transform

2019 ◽  
Author(s):  
Javad Padam
Keyword(s):  
Power Transformer ◽  
Computational Cost ◽  
Power Transformers ◽  
Inrush Current ◽  
Differential Protection ◽  
Two Phase ◽  
Transient Phenomena ◽  
S Transform ◽  
Three Phase ◽  
Clarke Transformation

Given that power transformers are one of the most important components of each network, their protection is an important part that the power transformer errors must be accurately identified and distinguished from each other. Therefore, identification and differentiation of transient phenomena of power transformers, including internal and external errors and magnetic inrush current are essential. In this research, Clarke transform and S transform were used to distinguish between these phenomena that the proposed algorithm is very suitable in terms of three characteristics of accuracy, speed and computational cost. Initially, the simulation of internal, external errors and magnetic inrush current of the transformer was performed for different transformer scenarios. For this purpose, 1060 signal tests were performed under different conditions. Subsequently, the signals of differential current obtained by Clarke transformation and S transformation were analyzed and appropriate criteria were extracted for detecting the current of internal errors from external errors and inrush current. The simulated internal and external errors include three- phase, three-phase to ground, two- phase, two- phase to ground and phase to ground error. Simulations were performed using PSCAD software and implementation of the proposed algorithm in MATLAB environment. The results of this study prevent the unwanted performance of differential protection to prevent undesirable electrifying. It is clear that the description of transient phenomena is the first step towards improving new ideas and criteria for protection with the greater reliability of power transformer which can be controlled better such unusual conditions that are currently used in equipment and relay.

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.

A Setting-Free Differential Protection for Power Transformers Based on Second Central Moment

2019 ◽  
Vol 34 (2) ◽  
pp. 750-759 ◽  
Author(s):  
Hector Esponda ◽  
Ernesto Vazquez ◽  
Manuel A. Andrade ◽  
Brian K. Johnson
Keyword(s):  
Central Moment ◽  
Power Transformers ◽  
Differential Protection

scholarly journals UHF Partial Discharge Location in Power Transformers via Solution of the Maxwell Equations in a Computational Environment

Sensors ◽  
2019 ◽  
Vol 19 (15) ◽  
pp. 3435 ◽  
Author(s):  
Luiz Nobrega ◽  
Edson Costa ◽  
Alexandre Serres ◽  
George Xavier ◽  
Marcus Aquino
Keyword(s):  
Electromagnetic Waves ◽  
Partial Discharge ◽  
Propagation Delay ◽  
Power Transformers ◽  
Computational Simulations ◽  
3D Space ◽  
Computational Environment ◽  
Three Phase ◽  
Discharge Location ◽  
Particle Swarm Optimisation Algorithm

This paper presents an algorithm for the localisation of partial discharge (PD) sources in power transformers based on the electromagnetic waves radiated by a PD pulse. The proposed algorithm is more accurate than existing methods, since it considers the effects of the reflection, refractions and diffractions undergone by the ultra-high frequency (UHF) signal within the equipment tank. The proposed method uses computational simulations of the electromagnetic waves generated by PD, and obtains the time delay of the signal between each point in the 3D space and the UHF sensors. The calculated signals can be compared with the signals measured in the field, so that the position of the PD source can be located based on the best correlation between the simulated propagation delay and the measured data. The equations used in the proposed method are defined as a 3D optimisation problem, so that the binary particle swarm optimisation algorithm can be used. To test and demonstrate the proposed algorithm, computational simulations were performed. The solutions were sufficient to identify not only the occurrence of defects, but also the winding and the region (top, centre or base) in which the defect occurred. In all cases, an accuracy of greater than 15 cm was obtained for the location, in a 180 MVA three-phase transformer.

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