A new algorithm to discriminate internal fault current and inrush current utilizing feature of fundamental current

2013 ◽  
Vol 36 (1) ◽  
pp. 26-31 ◽  
Author(s):  
Jing Ma ◽  
Zengping Wang ◽  
Shuxia Zheng ◽  
Tong Wang ◽  
Qixun Yang
Keyword(s):  
Inrush Current ◽  
Fault Current ◽  
Internal Fault

New Method to Identify Transformer Inrush Current Based on FFT and SVM

2013 ◽  
Vol 313-314 ◽  
pp. 887-890
Author(s):  
Mao Fa Gong ◽  
Guo Liang Li ◽  
Wen Hua Xia ◽  
Hong Lin Yan ◽  
Jing Wen Qu ◽  
...  
Keyword(s):  
Cross Validation ◽  
Accurate Method ◽  
High Accuracy ◽  
Generation Mechanism ◽  
New Method ◽  
Inrush Current ◽  
Fault Current ◽  
Third Harmonic ◽  
Internal Fault ◽  
Three Phase

To improve transformer longitudinal differential protections reliability, this paper deeply analyzes generation mechanism and characteristic of transformer inrush current, and uses PSCAD/EMTDC software to simulate 188 kinds of transformer operation states. They are including internal fault current, inrush current and no-load closing with internal fault. On the background of those simulations, it proposes a simple and accurate method to identify inrush current based on SVM. SVM selects Gaussion Kernel, and takes three-phase differential current, fundamental, secondary harmonic and third harmonic as characteristic quantities. Many cross-validation results verify that the training SVM has high accuracy. This method can identify inrush current and internal fault current (including no-load closing with internal fault current) rapidly and accurately. It takes less time, and is easy to perform.

Recognition of the Transformer Sympathetic Inrush Current Based on Hilbert-Huang Transform

2013 ◽  
Vol 441 ◽  
pp. 227-230
Author(s):  
Bin Qiao Zhang ◽  
Wei Wei Yao
Keyword(s):  
Wave Form ◽  
Inrush Current ◽  
Fault Current ◽  
Hilbert Huang Transform ◽  
Characteristic Quantity ◽  
Current Wave ◽  
Internal Fault ◽  
New Type ◽  
Form Features ◽  
Set Up

Analyze the characteristic quantity difference between the transformer sympathetic inrush current and the internal fault current inside it depending on the Hilbert-huang transform and extract the new type Hilbert-huang criterion for the recognition of the sympathetic inrush current according to the transformed wave form features. Set up the transformer simulating models through PACAD for the sympathetic inrush current and internal fault current to extract their IMF component; identify the sympathetic inrush current and the internal fault current based on HHT criterion; verify whether HHT criterion can identify the sympathetic inrush current wave form and the transformer internal fault current correctly. The criterion has targeted feature with self-adaption ability.

Identification of Transformer Inrush Current Based on Wavelet Packet Energy Spectrum

2015 ◽  
Vol 741 ◽  
pp. 340-343
Author(s):  
Mao Fa Gong ◽  
Mei Rong Li ◽  
Zheng Gong ◽  
Fan Jiao Yin ◽  
Zhong Gang Wang ◽  
...  
Keyword(s):  
Energy Spectrum ◽  
Frequency Band ◽  
High Frequency ◽  
Wavelet Packet ◽  
New Method ◽  
Inrush Current ◽  
Fault Current ◽  
High Frequency Band ◽  
Internal Fault ◽  
The Difference

In this paper, a new method using wavelet packet energy spectrum to identify transformer inrush and internal fault current was proposed. Wavelet packet transform respectively decomposed inrush and fault current, then calculated the energy of each frequency band of decomposed signal. Finally, the conclusion showed that the energy of internal fault in high frequency band is much less than that of inrush. The difference was quantified and it could be observed intuitively. Through extensive simulations, this paper proves that the method in terms of identifying transformer inrush is accurate and effective.

scholarly journals Numerical Differential Protection of Power Transformer using Innovative Algorithm

2019 ◽  
Vol 8 (5S3) ◽  
pp. 438-446
Keyword(s):  
Power Transformer ◽  
Algorithm Design ◽  
Point Of View ◽  
Inrush Current ◽  
Current Transformers ◽  
Simulink Model ◽  
Internal Fault ◽  
Safety And Reliability ◽  
Operating Current ◽  
Primary Current

This paper presents a new innovative algorithm for Numerical Differential Relay design of transformer. Fault information is critical for operating and maintaining power networks. This algorithm provides accurate performance for transformer by which is independent of system conditions such as: External fault, Inrush current, CT saturation. Locating transformer faults quickly and accurately is very important for economy, safety and reliability point of view. Both fault-detection and protection indices are derived by using Numerical Differential Relay algorithm design of transformer. The embedded based differential and operating current measurement device is called numerical differential relay is among the most important development in the field of instantaneous fault operation. Numerical relay provides measurement of differential current and operating current at power transformer above 5MVA in substation. Simulation studies are carried out using MATLAB Software show that the proposed scheme provides a high accuracy and fast relay response in internal fault conditions. Current transformers form an important part of protective systems. Ideal Current Transformers (CTs) are expected to reflect the primary current faithfully on the secondary side. Under conditions the CT saturates, and hence it cannot reproduce the primary current faithfully. This paper deals with simulation methods for determining CT performance under different factor. A Simulink model has been developed to observe CT response under steady state w.r.t Burden, Turns ratio, Asymmetrical current, Hysteresis conditions. Thus, it is now possible to evaluate the CT performance under these factors

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.

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