scholarly journals A Discrimination Method Between Transformer Inrush and Fault Current Based on Chromatic Monitoring

2021 ◽  
Vol 16 ◽  
pp. 308-315
Author(s):  
Ziyad S. Almajali
Keyword(s):  
Time Domain Analysis ◽  
Box Dimension ◽  
Inrush Current ◽  
Fault Current ◽  
Differential Protection ◽  
Transformer Protection ◽  
Short Time ◽  
Transformer Differential Protection ◽  
Correct Discrimination ◽  
Discrimination Method

or successful transformer differential protection employment, correct discrimination between inrush current and fault current is essential. It is one of the main focuses of research and one of the main challenges for transformer protection. In this paper, a discrimination method based on utilizing chromatic monitoring of the box dimension algorithm outcome curve for transformer differential current in time-domain analysis is proposed. The x-L chromatic mapping is employed for general detection of fault cases, while the x-y chromatic mapping result is used for distinguishing inrush current from the fault current cycles. The preliminary results show that the proposed method can effectively provide correct discrimination of the current type within quite a short time and thus help in providing efficient decision-making supportive protection tool.

scholarly journals A Method for Identification of Transformer Inrush Current Based on Box Dimension

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Maofa Gong ◽  
Ran Zheng ◽  
Linyuan Hou ◽  
Jingyu Wei ◽  
Na Wu
Keyword(s):  
Fundamental Difference ◽  
Box Dimension ◽  
Inrush Current ◽  
Fault Current ◽  
Differential Protection ◽  
Phase Current ◽  
Magnetizing Inrush Current ◽  
Three Phase ◽  
Transformer Differential Protection ◽  
Box Dimensions

Magnetizing inrush current can lead to the maloperation of transformer differential protection. To overcome such an issue, a method is proposed to distinguish inrush current from inner fault current based on box dimension. According to the fundamental difference in waveform between the two, the algorithm can extract the three-phase current and calculate its box dimensions. If the box dimension value is smaller than the setting value, it is the inrush current; otherwise, it is inner fault current. Using PSACD and MATLAB, the simulation has been performed to prove the efficiency reliability of the presented algorithm in distinguishing inrush current and fault current.

Simulation Design of Transformer Differential Protection Based on Mat Lab

2013 ◽  
Vol 722 ◽  
pp. 282-286
Author(s):  
Hong Hua He
Keyword(s):  
Simulation Model ◽  
Relay Protection ◽  
Fault Current ◽  
Differential Protection ◽  
Protection Device ◽  
Simulation Design ◽  
Transformer Protection ◽  
Internal Fault ◽  
Simulation Results ◽  
Transformer Differential Protection

The microprocessor-relay protection device has gradually replaced regular simulation relay protection it is also difficult to visually determine protection device malfunction or tripping. Therefore, the use of the Mat lab toolbox to build transformer differential protection simulation model, the simulation results show that two-line ratio brake can correctly identify internal fault current, and rapidly remove fault, and the system also can provide convenient for microprocessor transformer protection.

Simulation of Transformer Protection Based on an Embedded MATLAB Function

2014 ◽  
Vol 960-961 ◽  
pp. 995-999
Author(s):  
Wei Cai ◽  
Lin Sun ◽  
Hua Ren Wu
Keyword(s):  
Simulation Model ◽  
Second Harmonic ◽  
Circuit Breaker ◽  
Inrush Current ◽  
Differential Protection ◽  
Transformer Protection ◽  
Function Block ◽  
Internal Fault ◽  
Harmonic Restraint ◽  
Transformer Differential Protection

This paper establishes a simulation model of a simplified power system with transformer differential protection based on an embedded Matlab function block. The differential protection consists of percentage restraint differential protection, second harmonic restraint, differential current instantaneous trip protection and over-excitation protection. The model is able to correctly simulate the transformer’s inrush current and internal and external faults. The results from the simulation show that the circuit breaker correctly operates for a transformer internal fault and provides a good braking effect for an external fault. In addition, the protection model is able to identify the inrush current of the transformer and avoid a protection mis-trip event.

The Feasible Analysis of Transformer Fast Reenergizing with Neutral Point Ungrounded

2013 ◽  
Vol 732-733 ◽  
pp. 958-964
Author(s):  
Yao Zhao ◽  
Yu De Yang ◽  
Yan Hong Pan ◽  
Le Qi
Keyword(s):  
High Voltage ◽  
Power Supply ◽  
Low Voltage ◽  
Second Harmonic ◽  
Neutral Point ◽  
Inrush Current ◽  
Differential Protection ◽  
Time Saving ◽  
Magnetizing Inrush Current ◽  
Transformer Differential Protection

The feasibility of transformer fast reenergizing with neutral point ungrounded after the external fault being removed is analyzed in this paper. By calculating overvoltage and discriminating magnetizing inrush current, it analyzes four ways to restore power of transformer and chooses the optimal strategy which is safe and time-saving. The result shows that in the case of transformer neutral point ungrounded, closing the low-voltage circuit side breaker before the high-voltage, which can effectively limit over-voltage in a safe range. The second harmonic characteristic of magnetizing waveform may disappear, while the intermittent angle characteristics are still significant. With the help of the intermittent angle principle, transformer differential protection may not misuse. The average time for each customer interruption is reduced from 40 minutes to 10 minutes and saves an hour for engineer on the way back and forth. It will greatly improve power supply reliability.

A New Algorithm for Three-Phase Power Transformer Differential Protection Considering Effect of Ultra-Saturation Phenomenon Based on Discrete Wavelet Transform

2018 ◽  
Vol 20 (1) ◽  
Author(s):  
Bahram Noshad
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Power Transformer ◽  
Discrete Wavelet ◽  
Inrush Current ◽  
Differential Protection ◽  
Inductive Load ◽  
Saturation Phenomenon ◽  
Three Phase ◽  
Transformer Differential Protection

Abstract One of transient phenomena that lead to the false trip of the power transformer differential protection during the energization of a loaded power transformer is the ultra-saturation phenomenon. This paper presents, at first, a new algorithm for three-phase power transformer differential protection considering effect of the ultra-saturation phenomenon based on Discrete Wavelet Transform (DWT). To model the ultra-saturation phenomenon, the nonlinear characteristic of the transformer core and the effect of the saturation of the current transformers are taken into account. It is assumed that the load of the transformer is a resistive and inductive load. In this algorithm, the ultra-saturation phenomenon, the external and internal faults of power transformer and the magnetic inrush current are simulated. To distinguish between these phenomena, appropriate criteria using DWT by the use of standard deviation of coefficients are presented. Also, one of the most important criteria for the digital relays is the time for making a decision. Thus, to determine the time of decision, the experimental results will be presented.

Simulation and Analysis of Transformer Inrush Current and its Impact on Current Differential Protection

2013 ◽  
Vol 732-733 ◽  
pp. 712-716
Author(s):  
Hui Wang ◽  
Kun Yan ◽  
Hou Lei Gao ◽  
Xue Wei Chen
Keyword(s):  
Digital Simulation ◽  
Influence Factors ◽  
Generation Mechanism ◽  
Inrush Current ◽  
Differential Protection ◽  
Current Waveform ◽  
Current Differential Protection ◽  
Transformer Model ◽  
Transformer Fault ◽  
Transformer Differential Protection

A transformer model was built using PSCAD. The generation mechanism, waveform characteristics and influence factors of inrush current were simulated and analyzed. Combined with transformer differential protection, this paper discussed the conventional methods to identify inrush current and the operation logic to prevent mal-operation caused by inrush current. The typical transformer differential protection operating criteria were also simulated under different fault conditions. The results show that digital simulation can properly present inrush current waveform characteristics, different kinds of transformer fault status and inrush current influence on differential protection.

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