scholarly journals Simulink model of transformer differential protection using phase angle difference based algorithm

2020 ◽  
Vol 11 (2) ◽  
pp. 1088
Author(s):  
Nassim A. Iqteit ◽  
Khalid Yahya
Keyword(s):  
Phase Angle ◽  
Power Transformer ◽  
Inrush Current ◽  
Current Transformers ◽  
Phase Angle Difference ◽  
Simulink Model ◽  
Magnetizing Inrush Current ◽  
Angle Difference ◽  
Inrush Currents ◽  
Transformer Differential Protection

<p class="p1">An application of phase-angle-difference based algorithm with percentage differential relays is presented in this paper. In the situation where the transformer differential relay is under magnetizing inrush current, the algorithm will be utilized to block the process. In this study, the technique is modeled and implemented using Simulink integrated with MATLAB. The real circuit model of power transformer and current transformers are considered in the simulation model. The results confirmed the effectiveness of the technique in different operation modes; such as, magnetizing inrush currents, current transformers saturation and internal transformer faults.</p>

Evaluation of the Power Transformer Magnetizing Inrush Currents

2020 ◽  
Vol 10 (10) ◽  
pp. 20-32
Author(s):  
Aleksey A. KUVSHINOV ◽  
◽  
Vera V. VAKHNINA ◽  
Aleksey N. CHERNENKO ◽  
◽  
...  
Keyword(s):  
Power Transformer ◽  
Geomagnetic Disturbance ◽  
Inrush Current ◽  
Geomagnetic Disturbances ◽  
Disturbance Intensity ◽  
Magnetizing Inrush Current ◽  
Inrush Currents ◽  
Instantaneous Values ◽  
The Mathematical Model ◽  
Analytical Expressions

The mathematical model of a shell-core power transformer’s magnetization branch is substantiated. By using the model, analytical expressions for the magnetizing current instantaneous values under the conditions of geomagnetic disturbances can be obtained. Quantitative assessments of the magnetizing inrush current amplitudes and durations versus the geomagnetic disturbance intensity are obtained. The dynamics of the power transformer magnetic system saturation transient and changes in the magnetization inrush current amplitudes and durations after a sudden occurrence of geomagnetic disturbances are shown. The error of estimating the magnetizing inrush current amplitudes under geomagnetic disturbances is determined based on comparison with experimental data.

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

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.

scholarly journals Islanding Detection Using a Micro-Synchrophasor for Distribution Systems with Distributed Generation

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5180
Author(s):  
Karthikeyan Subramanian ◽  
Ashok Kumar Loganathan
Keyword(s):  
Distributed Generation ◽  
Phase Angle ◽  
Distribution Systems ◽  
Detection Algorithm ◽  
Rate Of Change ◽  
Islanding Detection ◽  
Phase Angle Difference ◽  
Angle Difference ◽  
Voltage Phase ◽  
Islanded Grid

Distributed Generation (DG) has changed the power generation system to small-scale instead of large-scale generation. The demanding issue with the interconnection of DG is the detection of unintended islanding in a network. Several methods proposed in the literature show drawbacks such as high non-detection zones (NDZ) and higher tripping time. In this paper, the IEEE 13 bus distribution network with DGs like wind and solar power plants is integrated at two buses. Islanding is detected by utilizing data from a micro-synchrophasor located at the distribution grid and the DG. The micro-synchrophasor-based unintended islanding detection algorithm is based on parameters such as voltage, rate of change of voltage, frequency, rate of change of frequency, voltage phase angle difference and the rate of change of the voltage phase angle difference between the utility and the islanded grid. The proposed islanding detection algorithm discriminates between islanding and non-islanding conditions and is highly efficient under zero power mismatch conditions. The proposed method has null NDZ and satisfies the IEEE 1547 standard for DG tripping time. The effectiveness of the proposed IDM was verified when there are multiple DGs in the islanded grid. Also, the proposed method does not require additional hardware as it can be incorporated in digital relays with synchrophasor functionality.

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.

scholarly journals Analysis of the Electromechanical Characteristics of Power Transformer under Different Residual Fluxes

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8244
Author(s):  
Wenqi Ge ◽  
Chenchen Zhang ◽  
Yi Xie ◽  
Ming Yu ◽  
Youhua Wang
Keyword(s):  
Power Transformer ◽  
Input Parameter ◽  
Electromagnetic Transients ◽  
Structural Parameter ◽  
Inrush Current ◽  
Parameter Variations ◽  
Inrush Currents ◽  
3D Finite Element Method ◽  
Opening And Closing ◽  
The Impact

When the electromagnetic transients occur in a power transformer, an inrush current is generated in its winding. The inrush current not only affects the performance of the transformer windings, but also affects the lifetime of the transformer. Many factors affect the inrush current, the most influential ones among which are the closing phase angle and the residual flux. In this paper, a dry-type transformer simulation model is built to analyze the influence of the inrush current on the performance of transformer windings during no-load reclosing conditions. Firstly, the inrush current was generated in the transformer windings during the no-load reclosing operation under different residual fluxes. Secondly, the field-circuit coupling 3d finite element method is used to analyze the electromagnetic force at different locations of the transformer windings under the influence of different inrush currents. The results of winding structural parameter variations are obtained through electromagnetic-structural coupling simulation, and the electromagnetic forces are used as the input parameter for the structural analysis. Finally, the residual flux is generated by controlling the opening and closing angle of the transformer through the phase-controlled switch, and the winding electromechanical characteristics are tested under different residual fluxes. Finally, comparisons of the test and simulation results are drawn to verify the impact of the closing angle and residual flux on inrush current and the winding deformation during the no-load reclosing conditions.

scholarly journals Differential Protection of Power Transformer using Wavelet Transform

2019 ◽  
Vol 8 (3) ◽  
pp. 7627-7630
Keyword(s):  
Wavelet Transform ◽  
Power Transformer ◽  
Circuit Breaker ◽  
Inrush Current ◽  
Differential Protection ◽  
Time Duration ◽  
Transform Method ◽  
Protection Scheme ◽  
Magnetizing Inrush Current ◽  
Clearing Time

This paper presents wavelet transform method for the analysis of differential currents of power transformer which can act as an accurate classifier between magnetizing inrush current and internal faults to avoid the needless tripping of circuit breaker. The differential protection scheme occasionally mal – operate whenever magnetizing inrush occurs in power transformer. The aim is to reduce the rate and time duration of undesired outages of power transformer. This includes the necessities of reliability with zero mal – operation of differential relay. The result shows higher operating speed with less fault clearing time. Wavelet Transform is employed for the analysis of transient signals under various conditions, which extracts data from signals in time and frequency domain simultaneously. The simulation is done in MATLAB environment.

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