Duty Cycle-Based Differential Protection Scheme for Power Transformers

Ji, Tianyao; Mo, Chun; Zhang, L. L.; Wu, Q. H.

doi:10.1109/tpwrd.2021.3086188

Cited by 8 publications

(4 citation statements)

References 30 publications

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“…Considering the fact that it is difficult and costly to determine an accurate threshold limit for protection algorithms in all different operating conditions and that an inaccurate threshold may result in the incorrect blocking of the DP or a delay in its operation, dependence on the threshold limit can be considered one of the main disadvantages of the protection methods presented in [8] and [7]. The authors in [4], [5], and [7] have not studied the accuracy of their methods in noise conditions. Nevertheless, the presence of noise may have a considerable effect on the accuracy and efficiency of those methods.…”

Section: Comparison With Related Workmentioning

confidence: 99%

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A power transformer differential protection method based on variational mode decomposition and CNN‐BiLSTM techniques

Afsharisefat,

Jannati,

Shams

2024

IET Generation Trans & Dist

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Power transformers play a critical role in the performance of power systems. This equipment is costly due to significant copper and iron prices and manufacturing costs. Therefore, maintenance and protection of such equipment is essential. Despite its robust performance, maloperation of differential protection (DP) in transformers may cause operational challenges to power system operators. The differential relay may operate incorrectly after the transformer energization leads to an inrush current (IC) and the relay identifies the event as an internal fault, and consequently issues the trip command. The other case of maloperation includes, but not limited to, a moment when the current transformer saturates due to an external fault. In this paper, a novel approach for DP is proposed, that is based on signal processing methods. In this paper, variational mode decomposition (VMD) and the deep neural network are implemented by using the convolutional neural network (CNN) and bi‐directional long short‐term memory (BiLSTM) models. The VMD decomposes differential current signal (DCS) to intrinsic mode functions with corresponding narrow‐band property frequency spectrums, which provides more detailed information about signal characteristics in different frequency bands. At the next stage, an effective feature for the BiLSTM is extracted by the CNN with the convolutional layers to classify events and proper discrimination. Extensive simulations on a 500 MVA transformer in MATLAB demonstrate the effectiveness of the proposed protection approach to differentiate ICs from internal and external faults with 99.8% accuracy in less than 1/8th of a power cycle.

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Section: Comparison With Related Workmentioning

confidence: 99%

“…Using threshold values to separate IFs from IC is one of the main disadvantages of the DP method. In [7], the security concerns associated with DP for power transformers are outlined. To overcome these issues, three protective criteria are proposed using the duty cycle concept.…”

Section: Introductionmentioning

confidence: 99%

A power transformer differential protection method based on variational mode decomposition and CNN‐BiLSTM techniques

Afsharisefat,

Jannati,

Shams

2024

IET Generation Trans & Dist

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“…The relay may operate during through fault due to spill current since the I di f f pickup was the only setting of the differential relay, which is highly undesirable. To mitigate this issue, restraining or biasing is provided based on the loading condition of the protected object through restraining coils, and their setting results in percentage bias characteristics (slope characteristics) of the relay, which essentially results in restraining the operation of the relay [13]. The restraint (biasing) characteristics provide stability to the differential relay during normal and through fault scenarios; therefore, the differential relays are called percentage biased differential relays.…”

Section: Differential Relaymentioning

confidence: 99%

A Detailed Testing Procedure of Numerical Differential Protection Relay for EHV Auto Transformer

et al. 2021

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In power systems, the programmable numerical differential relays are widely used for the protection of generators, bus bars, transformers, shunt reactors, and transmission lines. Retrofitting of relays is the need of the hour because lack of proper testing techniques and misunderstanding of vital procedures may result in under performance of the overall protection system. Lack of relay’s proper testing provokes an unpredictability in its behavior, that may prompt tripping of a healthy power system. Therefore, the main contribution of the paper is to prepare a step-by-step comprehensive procedural guideline for practical implementation of relay testing procedures and a detailed insight analysis of relay’s settings for the protection of an Extra High Voltage (EHV) auto transformer. The experimental results are scrutinized to document a detailed theoretical and technical analysis. Moreover, the paper also covers shortcomings of existing literature by documenting specialized literature that covers all aspects of protection relays, i.e., from basics of electromechanical domain to the technicalities of the numerical differential relay covering its detailed testing from different reputed manufacturers. A secondary injection relay test set is used for detailed testing of differential relay under test, and the S1 Agile software is used for protection relay settings, configuration modification, and detailed analysis.

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“…Power transmission and distribution technology can reduce energy loss and environmental pollution in the power system, thus playing a positive role in solving energy crisis and environmental problems. Protection and control technology is a very important part of the PET system, including modulation and soft switching technology, control technology and fault protection technology [1,2].…”

Section: Introductionmentioning

confidence: 99%

Research on protection and control technology of power electronic transformers

Sun

2023

ACE

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As the key equipment in the modern power system, the power electronic transformer's performance and reliability play a vital role in the stable operation of the power system. This paper studies the soft switching technology, control technology and fault protection method of power electronic transformer. First, the soft switching technology of power electronic transformers is introduced, including zero voltage switching, zero current switching and so on. These soft switching technologies can effectively reduce the switching loss of the transformer, improve efficiency, and reduce electromagnetic interference and harmonic generation. Secondly, the control technology of power electronic transformer is introduced, including traditional proportional, integral, and derivative control (PID) control, model predictive control and direct power control. These control technologies can realize the precise control of the output voltage and current of the power electronic transformer, to meet the requirements of the power system for power quality and stability. In addition, this paper also introduces the fault protection methods of power electronic transformers, including short-circuit protection, over-voltage protection and over-medium current protection. These fault protection methods can effectively protect power electronic transformers from various faults and ensure their normal operation and safety.

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Duty Cycle-Based Differential Protection Scheme for Power Transformers

Cited by 8 publications

References 30 publications

A power transformer differential protection method based on variational mode decomposition and CNN‐BiLSTM techniques

A power transformer differential protection method based on variational mode decomposition and CNN‐BiLSTM techniques

A Detailed Testing Procedure of Numerical Differential Protection Relay for EHV Auto Transformer

Research on protection and control technology of power electronic transformers

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