Simulation of Power Transformer Windings Displacement Caused by Multiple Short-Circuit Forces

2012 ◽  
Vol 268-270 ◽  
pp. 1341-1344
Author(s):  
Hong Kui Li
Keyword(s):  
Power Transformer ◽  
Short Circuit ◽  
Deformation Analysis ◽  
Theoretical Formula ◽  
Cumulative Impact ◽  
Elastic Plastic ◽  
Transformer Winding ◽  
Short Circuits ◽  
The Stability ◽  
The Impact

This research studies the displacement on the windings of transformer due to multiple short-circuit forces. The power transformer winding deformations cumulative impact of multiple short-circuits are studied. the cumulative impact of multiple short-circuit deformation of laminated cylindrical shell with stiffeners model is established, the impact of accumulated deformation of multiple short-circuit of transformer winding is calculated with large deformation elastic-plastic theory , the text introduced by the theoretical formula for power transformer windings of the elastic-plastic deformation analysis of and winding to determine the stability have great significance, To verify the computation results, they are compared with those obtained using ANSYS software simulation.

scholarly journals Performance of Parallel Connected SiC MOSFETs under Short Circuits Conditions

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6834
Author(s):  
Ruizhu Wu ◽  
Simon Mendy ◽  
Nereus Agbo ◽  
Jose Ortiz Gonzalez ◽  
Saeed Jahdi ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Short Circuit ◽  
Critical Factor ◽  
Charge Trapping ◽  
Parallel Connection ◽  
Bias Temperature Instability ◽  
Test Methodology ◽  
Threshold Voltages ◽  
Short Circuits ◽  
The Impact

This paper investigates the impact of parameter variation between parallel connected SiC MOSFETs on short circuit (SC) performance. SC tests are performed on parallel connected devices with different switching rates, junction temperatures and threshold voltages (VTH). The results show that VTH variation is the most critical factor affecting reduced robustness of parallel devices under SC. The SC current conducted per device is shown to increase under parallel connection compared to single device measurements. VTH shift from bias–temperature–instability (BTI) is known to occur in SiC MOSFETs, hence this paper combines BTI and SC tests. The results show that a positive VGS stress on the gate before the SC measurement reduces the peak SC current by a magnitude that is proportional to VGS stress time. Repeating the measurements at elevated temperatures reduces the time dependency of the VTH shift, thereby indicating thermal acceleration of negative charge trapping. VTH recovery is also observed using SC measurements. Similar measurements are performed on Si IGBTs with no observable impact of VGS stress on SC measurements. In conclusion, a test methodology for investigating the impact of BTI on SC characteristics is presented along with key results showing the electrothermal dynamics of parallel devices under SC conditions.

scholarly journals ANALYSIS OF MONI SIS OF MONITORING OF THE A ORING OF THE AT-3 AUTOTRANSFORM TRANSFORMATOR IN T OR IN TashTES MODE

2019 ◽  
Vol 2019 (1) ◽  
pp. 209-217
Author(s):  
F Isakov
Keyword(s):  
Cooling System ◽  
Power Transformer ◽  
Short Circuit ◽  
Operation Mode ◽  
Wear And Tear ◽  
Basic Parameters ◽  
Short Circuits ◽  
One Year ◽  
Insulation Breakdown ◽  
Winding Insulation

The article considers the results of the analysis of autotransformers operation mode monitoring. The time diagram of active load current and oil temperature of autotransformer TashTES AT-3 is established and during one year changes of these variables and basic parameters of autotransformer were observed. Technical faults of the power transformer and high power autotransformer are established and methods of their elimination are determined. Damage of transformers and autotransformers with voltage of 110-500 kV of about 30% of the total number of outages which were accompanied by internal short-circuits and two main causes of damage were determined. The main causes of technological failures, which were not accompanied by internal short-circuits, are as follows: 20% of failures in operation of the onload tap-changer, 16% of oil leaks from the bushings, 13% of oil leaks and lowering of oil from the transformer due to violation of welded joints and rubber seals, 4% of engine damage to oil pumps of the cooling system, 3% of pressure increase in high-voltage hermetic bushings, 2% of film protection shell damage. The main reasons of technological violations accompanied by internal short-circuit in the transformer are as follows: breakdown of internal insulation of highvoltage bushings, insufficient short-circuit resistance, wear and tear of winding insulation, breakdown of insulation.

Theoretical and Experimental Study on Mechanical Force of Transformer Coil Short Circuit

2017 ◽  
Vol 868 ◽  
pp. 283-290
Author(s):  
Jing Zhao ◽  
Ying Li ◽  
Shi Jie Wang ◽  
Ming Yin Yan
Keyword(s):  
Experimental Study ◽  
Power Distribution ◽  
Power Transformer ◽  
Short Circuit ◽  
Experimental System ◽  
Short Circuit Current ◽  
Mechanical Force ◽  
Transmission Equipment ◽  
Transformer Winding ◽  
Current Impact

As one of the most important components of transmission equipment in electric power field, power transformer bears the important task of energy conversion, power distribution and energy transfer. Because generated a huge force in transformer winding by its interior circuit excitation, it would be taken place easily to distortion, collapse and other damage of its structure, which brings a large safe and reliable problem. The lack of mechanical strength of the coil, which cannot withstand the sudden short-circuit current impact, led to the break of insulating layers, is one of the main causes in transformer failure. In this paper, it is discussed that theoretical and experimental study on mechanical force of transformer coil short circuit. According to the structural mechanics, the calculation of the contacted pressure between the coils is attained by building the contacted model. And the experimental system is been designed, which has a servo control system. Compared the theoretical and the Experimental data, the best accurate computed method for contacted pressure is obtained. It is helpful to improve the resistance ability for short circuit of transformer, and provide guarantee for the safe operation of the transformer.

scholarly journals Static and Dynamic Evaluation of a Winding Deformation FBG Sensor for Power Transformer Applications

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4877 ◽  
Author(s):  
Aguinaldo Goes de Melo ◽  
Daniel Benetti ◽  
Luiz Alkimin de Lacerda ◽  
Rodrigo Peres ◽  
Claudio Floridia ◽  
...  
Keyword(s):  
Power Transformer ◽  
Dynamic Pressure ◽  
Short Circuit ◽  
Pressure Sensors ◽  
Electric Power Industry ◽  
Inrush Current ◽  
Polyether Ether Ketone ◽  
Dielectric Sensor ◽  
Transformer Winding ◽  
Static Sensitivity

Power transformer is the most important and expensive equipment used in the electric power industry. Fiber Bragg grating (FBG) sensors has stood out as a flexible and particularly suitable tool for power transformer monitoring being a passive and dielectric sensor element. In this work we evaluated the performance of FBG pressure sensors developed to monitor the static and dynamic pressure in high voltage winding transformers during events such as short-circuit and inrush current. Two types of sensors packaging materials were evaluated in laboratory: polyether ether ketone (PEEK) and transformerboard (TB). The sensors have been tested for high intensity and short duration impacts similar to those occurring in short circuits. In addition, we evaluated the time response of sensors using an interrogation system with a 5 kHz sweep in order to analyze the short circuit response time properly. The results pointed that FBG pressure sensors using PEEK and TB are suitable for transformer winding monitoring. The static sensitivity obtained to PEEK based sensors was 0.911 pm/N, in the range of 800 N to 1500 N. This sensitivity is 4.47 higher than TB based sensors sensitivity. Dynamical tests performance showed an excellent repeatability for both sensors, in agreement with static observation.

An Innovative Solution for Type Testing of Power Transformers

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Manohar Singh ◽  
Vishnuvarddhan Telukanta ◽  
K S Meera
Keyword(s):  
Power Transformer ◽  
Short Circuit ◽  
Operating Conditions ◽  
Power Transformers ◽  
Test Facility ◽  
Online Testing ◽  
Testing Laboratory ◽  
Power Testing ◽  
Grid Operation ◽  
The Impact

Abstract Type tests are essential to assess the short circuit withstand capabilities of transformer windings. The mechanical durability of power equipment are checked against the mechanical forces developed during making/breaking short circuit operations. These type tests are generally carried out in indoor transformer test laboratories. Testing of Power Transformer for size more than 200 MVA in 765/400 kV voltage class in an indoor laboratory is not economically feasible. Now a days, power transformer manufacturers are fabricating single phase auto- power transformers of size up to 630 megawatt volt ampere (MVA) rating. Type testing of these transformers in indoor laboratories is not feasible. In view of this, strong short circuit fault feeding capabilities of the national grids can be utilized for type testing of these power transformers in an online manner. However, this may affect the grid operation/control during weak grid operating conditions. Recently, National High Power Testing Laboratory is established for testing of power transformer upto of 630 MVA. This is a unique online transformer test facility for testing of 765/400/220/132 kV class power transformers. An offline simulation has been carried out in this article, to assess the impact of online type testing on the Indian National grid. In this article, an online testing scheme has been presented which enables the national grid operator to analysis the prevailing grid condition & subsequently to decide the safe rating of the power transformer for online testing. The simulated results are cross checked with field results and it is found that simulated results are close to actual field results. The concurrence of simulated and field results helped in successfully commissioning of the testing laboratory.

Sign in / Sign up

Export Citation Format

Share Document