scholarly journals Experimental simulation analysis for single phase transformer tests

2020 ◽  
Vol 9 (3) ◽  
pp. 862-869
Author(s):  
Ali N. Hamoodi ◽  
Bashar A. Hammad ◽  
Fawaz S. Abdullah
Keyword(s):  
Single Phase ◽  
Simulation Analysis ◽  
Power Transformer ◽  
Short Circuit ◽  
Electrical Power ◽  
Load Test ◽  
Experimental Simulation ◽  
Electrical Power System ◽  
Test Procedures ◽  
Short Circuit Test

Transformer is one of main components in electrical power system which role to increase or reduce voltage. Characteristics of transformer would be vital to ensure the voltage is fully transferred. A single-phase transformer is a type of power transformer that utilizes single-phase alternating current, meaning the transformer relies on a voltage cycle that operates in a unified time  phase. This article describes a workflow executed with Mat lab simulation and practical measurements for single-phase power transformer, no-load, short-circuit test and load test are achieved in this work. The test procedures are implemented on areal transformer (terco-type) which has a specification (1 KVA, 220/110 V, 50 Hz). Finally, the simulation results are appeared a proximately seminar from the practical results. The results indicated that the the technique and manner which presented in the current study can be depended as a miniproject in electrical technology mater for undergraduate studies.

scholarly journals Grid-like Vibration Measurements on Power Transformer Tank during Open-Circuit and Short-Circuit Tests

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 492
Author(s):  
Karlo Petrović ◽  
Antonio Petošić ◽  
Tomislav Župan
Keyword(s):  
Power Transformer ◽  
Short Circuit ◽  
Frequency Component ◽  
Open Circuit ◽  
Load Test ◽  
Mode Shapes ◽  
Vibration Velocity ◽  
Tank Wall ◽  
Vibration Measurements ◽  
Short Circuit Test

In this work, the vibrations on the surfaces of the tank wall, stiffeners, and the cover of a 5 MVA transformer experimental model were measured during open-circuit and short-circuit transformer tests. Vibration measurements of a transformer tank side were conducted at discrete points using two different voltage sources in no-load test. Using interpolation functions, the RMS values of acceleration and vibration velocity are visualized and compared for each considered measurement configuration (no-load and load tests and two different excitation sources). Significant differences in mode shapes and amplitudes of vibrations at different frequencies are observed. The maximum RMS values of acceleration, velocity and displacement in the open-circuit test are 0.36 m/s2, 0.31 mm/s, and 0.42 µm, respectively. The maximum values in short-circuit test are 0.74 m/s2, 1.14 mm/s, and 1.8 µm, respectively. In the short-circuit test, the frequency component of 100 Hz is dominant. In the open-circuit test, the first few 100 Hz harmonics are significant (100 Hz, 200 Hz, and 300 Hz). In addition to the visualization of RMS values during the open-circuit and short-circuit tests, animations of the vibrations are created. Fourier analysis and phase comparison between frequency components are also used to show vibration animations at dominant frequencies in the spectrum (100 Hz harmonics). The visualization of the vibrations at the tank wall surfaces is transferred into 3D space in such a way that all 15 surfaces are mapped to the spatial coordinates of the surfaces so that a 3D model of the acceleration, vibration velocity, and displacement of the transformer tank is shown.

Augmented Short-Circuit Test for the Measurement of Transformer Equivalent-Circuit Parameters with Large Series Branch Impedances

2010 ◽  
Vol 47 (1) ◽  
pp. 86-93
Author(s):  
Saurabh Kumar Mukerji ◽  
Moleykutty George
Keyword(s):  
Equivalent Circuit ◽  
High Voltage ◽  
Single Phase ◽  
Short Circuit ◽  
Large Series ◽  
Test Results ◽  
Voltage Supply ◽  
Short Circuit Test ◽  
Equivalent Circuit Parameters

An augmented short-circuit test is described for the determination of equivalent-circuit parameters of single-phase transformers with large series-branch impedances. This test may be conducted at rated currents with the transformer connected to a reduced voltage supply. Thus harmonics in current and voltage waves are negligible. This test is therefore free from harmonics-associated errors. Based on test results, phasor equations are found which give formulae for the equivalent-circuit parameters with series-branch impedance split into low- and high-voltage components.

Axial Nonlinear Mechanical Vibrations of Large Power Transformer Windings During Short Circuit

2001 ◽  
Author(s):  
Jian-Xue Xu ◽  
Zhen-Mao Chen
Keyword(s):  
Steady State ◽  
Shooting Method ◽  
Single Phase ◽  
Power Transformer ◽  
Short Circuit ◽  
Mathieu Equation ◽  
Response Force ◽  
Dynamical Response ◽  
Large Power ◽  
The Time Domain

Abstract In this paper, the axial nonlinear vibrations of the transformer winding under steady state operation case and short circuit case are studied in single degree and multi-degree models. In the case of having ampere-turn balance, the steady state response of the former model is obtained by using multi-scale method and periodic shooting method, analytically and numerically. At the same time, the computing method of Jacobi matrix in the periodic shooting method has been modified, so that the computing CPU time is saved. For multi-degree mechanical model of a single phase transformer windings, the time domain response and relation between the response and various parameters are obtained by Runge-Kutta method. For ampere-turn unbalance case, an electric-mechanical coupled problem, that the electric force depends the displacement of the winding are foomed, and the nonlinear forced Mathieu equation is established for this problem; and then the nonlinear dynamical response and global dynamical behaviors are analyzed. Finally, for a 20 MVA single phase three windings transformer, a series of short circuit experiments have been performed and the axial dynamical response force, magnetic field, strain etc. have been measured. The theoretical results well agree with the experimental results.

scholarly journals Effect of load current harmonics on vibration of three-phase generator

2018 ◽  
Vol 197 ◽  
pp. 11023
Author(s):  
I Made Wiwit Kastawan
Keyword(s):  
Single Phase ◽  
Electrical Power ◽  
Electrical Power System ◽  
Negative Effects ◽  
Load Current ◽  
Current Harmonics ◽  
Three Phase ◽  
Non Linear ◽  
Electrical Loads ◽  
Linear Loading

Almost all today electrical loads are considered non-linear such as switch mode power supply (SMPS) for powering computer and mobile phone or variable speed drive (VSD) for driving home and industrial electric motors. These loads generate ac non-sinusoidal current containing a lot of harmonics as indicated by its high total harmonics distortion (THD) figure. Current harmonics bring negative effects into all electrical power system components, including three-phase generator. This paper provides analysis of load current harmonics effects on vibration of three-phase generator. Three different laboratory experiments have been conducted i.e. three-phase linear resistive loading, non-linear loading with a three-phase ac/dc converter and non-linear loading with three single-phase capacitor filtered ac/dc converters. Results show that the higher load current harmonics content the higher is vibration of the three-phase generator. Non-linear loading with a three-phase ac/dc converter that generate about 24.7% THD gives an increase of 4.3% and 5.5% in average of vertical and horizontal vibrations of the three-phase generator respectively. Further, non-linear loading with three single-phase capacitor filtered ac/dc converters that generate THD as high as 74.9% gives significant increase of 28.1% and 23.6% in average of vertical and horizontal vibrations respectively.

Power Plant Station Protection System against Voltage Fluctuation

2015 ◽  
Vol 793 ◽  
pp. 65-69 ◽  
Author(s):  
Abadal Salam T. Hussain ◽  
Waleed A. Oraibi ◽  
Fadhel A. Jumaa ◽  
F. Malek ◽  
Syed F. Ahmed ◽  
...  
Keyword(s):  
Power Plant ◽  
Power System ◽  
Short Circuit ◽  
Electrical Power ◽  
Circuit Breaker ◽  
Digital Signal ◽  
Short Circuit Current ◽  
Electrical Power System ◽  
System Protection ◽  
Protective Relay

Electrical Power System protection is required to protectboth the user and the system equipment itself fromany fault, hence electrical power system is not allowed to operate without any protection devices installed. Power System fault is defined as the undesirable condition that occurs in the power system. Some of these undesirable conditions are short circuit, current leakage, ground faultand over-under voltage. With the increasing loads, voltages and short-circuit duty in power plant, over voltage protection has become more important today. Here, the component that had been used is PIC 16F877a microcontroller to control the whole system and especially on the circuit breakers as well as the LCT display unit is used to display the voltage level and type of generator that used to serve the load. Sensors are used to measure both thevoltage and the load. The controlled digital signal from PIC microcontroller is converted by using the digital analog converter to control the whole circuit. Thus a device called protective relay is created to meet this requirement. The protective relay is mostlyoften coupled with circuit breaker in a way that it can isolate the abnormal condition in the system.

Design, Construction and Performance Evaluation of a Low Cost Electric Arc Welding Machine

2009 ◽  
Vol 62-64 ◽  
pp. 135-140
Author(s):  
S.O. Igbinovia ◽  
M.C. Onuoha ◽  
O.K. Olaogun
Keyword(s):  
Arc Welding ◽  
Low Cost ◽  
Short Circuit ◽  
Electric Arc ◽  
Load Test ◽  
Welding Machine ◽  
Short Circuit Test ◽  
Operating Current ◽  
Electric Arc Welding ◽  
And Performance

Apart from woodwork, brickwork, all other formworks are of metalwork. Thus engineering devices, equipment, machineries and infrastructures are made possible with the use of welding machines, be it carbide or arc – welding type. In Nigeria, where the cost of imported goods rises astronomically in accordance with the foreign exchange rates, the need to fabricate this very important equipment became of important necessity. In this paper, a single-phase 6KVA, 240VAC/30-70 VDC electric arc welding machine was designed and constructed using locally available materials. The different operating current required, arcing time, the heat generated by the arc, the minimum arc gap, the fluxite coated electrode, oxidation of the molten materials by the surrounding air where some of the designed parameters that determined the auto-transformer specific magnetic loading and specific electric loading. Cooling medium, integral switch, the rectifier circuits and the tanking of the transformer designed determined the equipment production. The locally fabricated AC/DC air cooled electric arc welding machine capable of withstanding 200A, when subjected to insulation resistance test, no – load test, short circuit test and on-load test to ascertain its performance characteristics were very satisfactory.

scholarly journals Impacts of Placement of Wind Turbine Generators on IEEE 13 Node Radial Test Feeder In-Line Transformer Fuse-Fuse Protection Coordination

2020 ◽  
Vol 5 (6) ◽  
pp. 665-674
Author(s):  
Kemei Peter Kirui ◽  
David K. Murage ◽  
Peter K. Kihato
Keyword(s):  
Power System ◽  
Short Circuit ◽  
Electrical Power ◽  
Distribution Network ◽  
Electrical Energy ◽  
Distribution Transformer ◽  
Electrical Power System ◽  
Turbine Generators ◽  
Wind Turbine Generators ◽  
Network Operations

The ever increasing global demand on the electrical energy has lead to the integration of Distributed Generators (DGs) onto the distribution power systems networks to supplement on the deficiencies on the electrical energy generation capacities. The high penetration levels of DGs on the electrical distribution networks experienced over the past decade calls for the grid operators to periodically and critically asses the impacts brought by the DGs on the distribution network operations. The assessment on the impacts brought by the DGs on the distribution network operations is done by simulating the dynamic response of the network to major disturbances occurring on the network like the faults once the DGs have been connected into it. Connection of Wind Turbine Generators (WTGs) into a conventional electrical energy distribution network has great impacts on the short circuit current levels experienced during a fault and also on the protective devices used in protecting the distribution network equipment namely; the transformers, the overhead distribution lines, the underground cables and the line compensators and the shunt capacitors commonly used/found on the relatively long rural distribution feeders. The main factors which contribute to the impacts brought by the WTGs integration onto a conventional distribution network are: The location of interconnecting the WTG/s into the distribution feeder; The size/s of the WTG/s in terms of their electrical wattage penetrating the distribution network; And the type of the WTG interfacing technology used labeled/classified as, Type I, Type II, Type III and Type IV WTGs. Even though transformers are the simplest and the most reliable devices in an electrical power system, transformer failures can occur due to internal or external conditions that make the transformer incapable of performing its proper functions. Appropriate transformer protection should be used with the objectives of protecting the electrical power system in case of a transformer failure and also to protect the transformer itself from the power system disturbances like the faults. This paper was to investigate the effects of integrating WTGs on a distribution transformer Fuse-Fuse conventional protection coordination scheme. The radial distribution feeder studied was the IEEE 13 node radial test feeder and it was simulated using the Electrical Transient Analysis Program (ETAP) software for distribution transformer Fuse-Fuse protection coordination analysis. The IEEE 13 Node radial test feeder In-line transformer studied is a three-phase  step down transformer having a star solidly grounded primary winding supplied at  and a star solidly grounded secondary winding feeding power at a voltage of . The increase on the short circuit currents at the In-line transformer nodes due to the WTG integration continuously reduces the time coordination margins between the upstream fuse F633 and the downstream fuse F634 used to protect the transformer.

scholarly journals Effects of VA Rating on the Fault Diagnosis of Power Transformer Using SFRA Test

2021 ◽  
Vol 23 (5) ◽  
pp. 381-389
Author(s):  
Khalid H. Ibrahim ◽  
Nourhan R. Korany ◽  
Saber M. Saleh
Keyword(s):  
Fault Diagnosis ◽  
Power Transformer ◽  
Electrical Power ◽  
Mechanical Damage ◽  
Response Analysis ◽  
Electrical Power System ◽  
Statistical Parameters ◽  
Functional Interpretation ◽  
Emission Analysis ◽  
Main Challenge

The electric power transformer is an essential part of an electrical power system since it is used to step up or down voltage levels to maintain the system performance as well as possible. Frequency response analysis (FRA) is one of the most widely used techniques for detecting various types of mechanical damage in transformers. The equivalent circuit of the transformer will be represented by a complex network of R, L, and C elements in the FRA technique. For transformer faults diagnosis, various calculation techniques and diagnostic techniques may be used, such as acoustic emission analysis, thermal images of electromagnetic radiation, transformer temperature, and humidity analysis. SFRA test is one of these techniques that could be used to determine the fault type based on its response over a wide frequency range. The main challenge of the SFRA test is that the functional interpretation requirement for this test is not universally accepted Also statistical features are defined for this SFRA response to be used in fault detection and classification. In this paper, the effect of the transformer rating on the fault diagnosis techniques using SFRA is tested. Also, the effect of the transformer VA rating on the statistical parameters and the classification rules of fault diagnosis is discussed. Finally, the features used in fault diagnosis are ranked according to its independence of the transformer rating resulting in a more accurate matching fault diagnosis technique.

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