scholarly journals Reliability Enhancement of Power IGBTs under Short-Circuit Fault Condition Using Short-Circuit Current Limiting-Based Technique

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7397
Author(s):  
Sadegh Mohsenzade ◽  
Javad Naghibi ◽  
Kamyar Mehran
Keyword(s):  
Temperature Rise ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Bipolar Transistors ◽  
Junction Temperature ◽  
Control Approach ◽  
A Value ◽  
Semiconductor Switch ◽  
Simulation And Experiment ◽  
Short Circuit Fault

Like the widely-used semiconductor switch, Insulated Gate Bipolar Transistors (IGBTs) are subject to many failures and degradation in power electronic converters. In Short Circuit Fault (SCF), as the most reported failures in IGBTs, drastic, sudden temperature rise, and peak SCF current are widespread failures owing to a relatively long delay of the protection subsystem. This paper proposes a protection strategy to limit the junction temperature rise by limiting the SCF current by adding a small value resistor in the IGBT emitter. Second, it reduces the SCF current to a value much less than the saturated current. With the proposed control approach, sudden temperature rise during SCF is controlled, preventing significant failure in IGBTs. The extension of the permissible SCF time is achieved even for the cases with temporary arcs. A simple control loop activates in the SCF condition and does not create slow transients for the IGBT. The results of this paper are validated through simulation and experiment.

Current Limiting Reactor's Reactance Value Selection Based on Short-Circuit Transient Analysis

2013 ◽  
Vol 722 ◽  
pp. 223-227
Author(s):  
Tie Ying Zhao ◽  
Yan Wen Wang
Keyword(s):  
Transient Process ◽  
Transient Analysis ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Engineering Calculation ◽  
Calculation Formula ◽  
Current Limiting ◽  
Current Change ◽  
Short Circuit Fault ◽  
A Current

Current limiting reactor can increase systems short circuit impedance so as to limit short circuit current. Current limiting reactor is directly involved in whole short circuit process when a short circuit fault occurs in a power system, which makes short-circuit current change more complex. Short circuit current level is affected by current limiting reactors parameters; a current limiting reactor with proper impedance value can maintain short-circuit current at an acceptable range. A short circuit transient process of a distributing network with current limiting reactor was analyzed, and the formula of current changing in short circuit transient process was deduced; according to the current changing formula, an engineering calculation formula of current limiting reactors impedance was derived. The case calculation shows that current limiting reactor meeting the need of the engineering calculation formula can reach the system current limiting requirement.

scholarly journals Online Estimation of Short-Circuit Fault Level in Active Distribution Network

2020 ◽  
Vol 10 (11) ◽  
pp. 3812
Author(s):  
Xiaohui Wang ◽  
Peng Wang ◽  
Yunbo Wang ◽  
Fang Shi
Keyword(s):  
Equivalent Circuit ◽  
Short Circuit ◽  
Distribution Network ◽  
Estimation Method ◽  
Short Circuit Current ◽  
Distribution Networks ◽  
Measurement Unit ◽  
Online Estimation ◽  
Active Distribution Network ◽  
Short Circuit Fault

The potential short-circuit current in active distribution network features time-variance with the increasing distributed generations. This feature makes the online estimation of fault level necessary. In this paper, a novel online estimation method is proposed to be implemented by either phasor measurement unit (PMU) or the measurements from protection relays. The equivalent circuit of the radial distribution network with distributed generators (DGs), e.g., wind turbines and photovoltaic cells, is derived with necessary simplifications. The natural disturbances downstream are used to evaluate the parameters of the equivalent circuit so that the potential fault level can be estimated in advance of the actual fault occurrence. A fuzzy logic identifier is presented to rank the confidence of the measurements incurred by the disturbance and to distinguish the qualified disturbance to launch the estimation. The mechanism based on multi-measurements and confidence indices was applied, to improve the accuracy. A typical distribution network in the United Kingdom (UK) with DGs was taken, as an example, to validate the proposed method under various load fluctuation. The results confirm the effectiveness of the proposed method, which is suitable for online estimation of short-circuit fault level in active distribution networks.

A New Method of Short-Current Limiting

2014 ◽  
Vol 945-949 ◽  
pp. 2846-2849
Author(s):  
Hui Xu ◽  
Zhong Dong Yin
Keyword(s):  
Control Strategy ◽  
Short Circuit ◽  
Device Simulation ◽  
Short Circuit Current ◽  
Simulation Software ◽  
Current Limit ◽  
Quality Control Strategy ◽  
And Control ◽  
Short Circuit Fault ◽  
Parallel Type

This research proposes a new parallel-type short-circuit current limit adjustment device. A unified power quality control strategy is provided to solve the typical issues of the power system. Meantime，when short-circuit fault occurs in the load side，short-circuit current can be limited to minimal range. The parallel-type short-circuit current limit adjustment device simulation model is established based on PSCAD/EMTDC simulation software. By doing some experiments on the parallel short-circuit current limit adjustment device, the correctness and validity of the proposed main circuit topology and control strategy is validated.

scholarly journals Optical Property and Photoelectrical Performance of a Low-bandgap Conducting Polymer Incorporated with Quantum Dots Used for Organic Solar Cells

2015 ◽  
Vol 25 (2) ◽  
pp. 139
Author(s):  
Tran Thi Thao ◽  
Vu Thi Hai ◽  
Nguyen Nang Dinh ◽  
Le Dinh Trong
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Organic Solar Cells ◽  
Fill Factor ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Low Bandgap ◽  
A Value

By using spin-coating technique, a low bandgap conjugated polymer, poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopen-ta[2,1-b;3,4-b′]dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT)  and its composite thin films have been prepared. The optical absorption and photoconductive properties with over a wide spectral range, from 350 to 950  nm, were characterized. The obtained results showed that PCPDTBT:10 wt% CdSe  composite is the most suitable for efficient light-harvesting in polymer-based photovoltaic cells. The photoelectrical conversion efficiency (PCE) of the device with  a multilayer structure of ITO/PEDOT/ PCPDTBT:CdSe /LiF/Al  reached a value as large as 1.34% with an open-circuit voltage (Voc) = 0.57 V, a short-circuit current density (Jsc) = 4.29 mA/cm2, and a fill factor (FF) = 0.27. This suggests a useful application in further fabrication of quantum dots/polymers based solar cells.

Study on Technical Parameters for 220/20kV SF6 Gas Insulated Transformers

2014 ◽  
Vol 1070-1072 ◽  
pp. 1056-1065
Author(s):  
Zhi Yong Wang ◽  
Zhi Yong Dai ◽  
Hao Xi Tu
Keyword(s):  
Temperature Rise ◽  
Noise Level ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Cooling Mode ◽  
Technical Parameters ◽  
Gas Cooling ◽  
Gas Insulation ◽  
Selection For ◽  
Circuit Impedance

Considering the requirement of Shenzhen power grid development, this paper investigates the parameters selection for 220/20kV gas insulation transformer, including capacity, short circuit impedance, cooling mode, insulation level, over-load capability, temperature rise tolerance, loss , noise level and bushing selection. For different capacity value, the investment and loss concerning substation, 220kV grid and 20kV grid are analyzed and compared, by which the final capacity value is determined. The short circuit current level, transformer loss, manufacturing capability and investment is investigated to determine the short circuit impedance for the gas insulation transformer. The characteristic and application condition of gas cooling as well as liquid cooling mode is studied and the cooling mode for the gas insulation transformer is determined. The insulation level, overload capability and temperature rise tolerance are determined by considering related standards and the requirement of Shenzhen. The loss and noise level for the gas insulation transformer is determined by considering related standard and parameters of the domestic gas insulation transformers in operation. The gas-gas bushing is used to connect cable box and the transformer.

Symmetrical Short Circuit Current Characteristics of Doubly Fed Induction Generator Wind Turbine with Crowbar Protection

2012 ◽  
Vol 512-515 ◽  
pp. 782-787
Author(s):  
Jia Jun Zhai ◽  
Bu Han Zhang ◽  
Kui Wang ◽  
Wen Shao ◽  
Cheng Xiong Mao
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Operating Characteristics ◽  
Doubly Fed ◽  
Crowbar Protection ◽  
Short Circuit Fault

Doubly fed induction generator (DFIG) is now becoming one of most widely used wind turbines in global market for wind power generation, due to its outstanding advantages. However, the DFIG is sensitive to grid faults. The DFIG will have to be removed from the grid if there’s no protection appliance in it. Therefore, the crowbar protection is widely used in the world for improving the low voltage ride-through ability of wind turbines. This paper analysed the operating characteristics and short-circuit current of DFIG under symmetrical short-circuit fault with respect to different sags to grid voltage, which on the basis of DFIG wind turbine with crowbar protection. And the expressions of short-circuit current under symmetrical short-circuit fault for DFIG were derived. The effectiveness of the expression was simulated in PSCAD/EMTDC.

scholarly journals STUDI PENGARUH PEMASANGAN NGR 40 OHM PADA UPRATING TRANSFORMATOR 2 GI GIANYAR TERHADAP GANGGUAN HUBUNG SINGKAT 1 PHASA TANAH

2017 ◽  
Vol 16 (2) ◽  
pp. 112
Author(s):  
Arya Surya Darma ◽  
I Gede Dyana Arjana ◽  
A.A Gede Maharta Pemayun
Keyword(s):  
Short Circuit ◽  
Electrical Power ◽  
Short Circuit Current ◽  
Fault Current ◽  
Safety Equipment ◽  
Grounding Resistance ◽  
A Value ◽  
Current Setting ◽  
Earthing Systems ◽  
Time Relay

Along with the development of ever-increasing burden on the GI Gianyar then the transformer unit 2 with a capacity of 30 MVA will be uprating with a capacity of 60 MVA transformer. To maintain the continuity and reliability of the flow of electrical power to the consumer , NGR (Neutral Grounding Resistance) and relay SBEF is used as the safety equipment of the short circuit 1 phase to ground was not in to the neutral point of the transformer. Uprating of transformers that have been done changes on 1 phase fault current to ground when using a direct earthing systems with a value to become 1838.21 A. While the value of the short-circuit current 1 phase to ground after pairing NGR 40 Ohm value is fixed at 288.675 A, so that the current setting and time relay SBEF fixed at 90 A and 7.067 seconds. The analysis result from the effect of installation NGR and rele SBEF on the transformer 60 MVA against short circuit 1 phase to ground has the ability good protection for the value of the fault current is able to be reduced from 1838,21 A into 288.675 A after pairing NGR 40 Ohm and time is needed SBEF to handle distractions 7.067 seconds. Intisari- Seiring dengan perkembangan beban yang terus meningkat di GI Gianyar maka transformator unit 2 berkapasitas 30 MVA akan di lakukan uprating (penggantian) dengan transformator berkapasitas 60 MVA. Untuk menjaga kontinyuitas dan keandalan aliran daya listrik sampai ke konsumen (beban), NGR (Neutral Grounding Resistance) dan rele SBEF dipergunakan sebagai peralatan pengaman dari gangguan hubung singkat phasa tanah agar arus gangguan 1 phasa ke tanah tidak sampai mengalir ke titik netral transformator. Dari uprating transformator yang sudah di lakukan terjadi perubahan pada arus gangguan 1 phasa ke tanah jika menggunakan sistem pentanahan langsung (solid grounding) menjadi 1838,21 A. Sedangkan nilai dari arus hubung singkat 1 phasa ke tanah setelah dipasangkan NGR 40 Ohm nilainya tetap sebesar 288,675 A, sehingga setting arus dan waktu rele SBEF tetap sebesar 90 A dan 7,067 detik. Hasil analisis pengaruh pemasangan NGR dan rele SBEF pada transformator 60 MVA terhadap gangguan hubung singkat 1 phasa ke tanah menghasilkan kemampuan proteksi yang lebih baik karena nilai arus gangguan yang mampu di kurangi dari 1838,21 A menjadi 288,675 A setelah dipasangkan NGR 40 Ohm dan waktu yang di butuhkan SBEF untuk menangani gangguan 7,067 detik.

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