scholarly journals Optimal Selection of Time-Current Characteristic of Overcurrent Protection for Induction Motors in Drives of Mining Machines with Prolonged Starting Time

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4466
Author(s):  
Jarosław Joostberens ◽  
Adam Heyduk ◽  
Sergiusz Boron ◽  
Andrzej Bauerek
Keyword(s):  
Cross Sections ◽  
Induction Motors ◽  
Supply Voltage ◽  
Voltage Drop ◽  
Power Supply Voltage ◽  
Current Characteristic ◽  
Starting Time ◽  
Overcurrent Protection ◽  
Starting Torque ◽  
Selection Of

The aim of this study is to analyze the effects of mine power network impedance on the starting time of induction motors, as well as on the operation of overcurrent protection relay. Proper selection of the time-current characteristic of overcurrent protection is crucial for the operation of the drive. A specific feature of mining power grids is their high impedance, which results from long cable lines with relatively small cross-sections. This causes relatively large voltage drops and significantly reduces the starting torque of the motor. Reduced starting torque increases the starting time and intensifies the motor overheating. This study analyzes a series of standardized time-current characteristics used in Invertim company protection devices. A simulation study of startup current and starting time was conducted for an exemplary medium-power motor with a large inertia fan at different values of power supply voltage below the rated value. Parameters of the motor equivalent circuit were calculated on the basis of manufacturer data. A new shape of the time-current characteristic has been proposed that would allow for prolonged starting at significant voltage drop in the mine network, ensuring protection from failed starting. This solution can be implemented in digital protection relays in addition to the standard characteristics.

Investigating the Applicability of Graphene Nanoribbon as Signal and Power Interconnects for Nanometer Designs

2015 ◽  
Vol 25 (02) ◽  
pp. 1650001 ◽  
Author(s):  
Debaprasad Das ◽  
Hafizur Rahaman
Keyword(s):  
Supply Voltage ◽  
Voltage Drop ◽  
Graphene Nanoribbon ◽  
Switching Noise ◽  
Crosstalk Noise ◽  
Power Supply Voltage ◽  
Graphene Layers ◽  
Ir Drop ◽  
Simultaneous Switching ◽  
Better Than

In this work, we have investigated the applicability of graphene nanoribbon (GNR) as the interconnects for 16-nm ITRS technology node. GNR is proposed as the possible alternative to the traditional copper (Cu)-based interconnect systems in nanometer regime. In this paper, we have performed important studies on GNR for its applicability as power and signal interconnects. For the application of power interconnects, we have investigated the power supply voltage drop (IR drop) and simultaneous switching noise (SSN) in graphene-based interconnect system. We have performed crosstalk noise and overshoot/undershoot analyses for the application of signal interconnects. The results are compared with that of the traditional Cu-based interconnects. The results show that GNR is better than Cu as far as IR drop, SSN, gate oxide reliability and hot carrier reliability are concerned. Our investigation reveals that GNR can be better than the Cu interconnects from all aspects with a multilayer GNR structure. The present graphene-based interconnect technology needs to be advanced, so that the metal–graphene contact resistance is minimized and multilayer GNR structure with large number of graphene layers is supported.

scholarly journals Analysis of the influence of zero potential live operation on protection

2020 ◽  
Vol 152 ◽  
pp. 03004
Author(s):  
Qi Yang ◽  
Zhenyu Wang ◽  
Liang Zhu ◽  
Li Xu ◽  
Chaohui Zhen
Keyword(s):  
Power Supply ◽  
Impact Analysis ◽  
Supply Voltage ◽  
Voltage Drop ◽  
Distribution Network ◽  
Neutral Point ◽  
Power Supply Voltage ◽  
Current Curve ◽  
Zero Sequence ◽  
Zero Potential

In the case of live working in the distribution network, a live method of live working that satisfies the requirements for personal safety and power supply reliability needs to be studied, because of the serious safety accidents caused by misuse and weak safety awareness. Based on the analysis of singlephase buck symmetrical operation characteristics, a new method of zero-potential live working of distribution network based on injection current is proposed. By injecting current into the neutral point, the zero-sequence voltage is regulated so that the neutral point voltage is equal to the value of the operating phase line voltage drop minus the operating phase power supply voltage, ensuring that the operating point voltage is zero. Based on the principle of current fast-break protection and time-limited overcurrent protection, it is analyzed that the zero-potential uninterruptible operation method of the distribution network will not affect the distribution network protection. Finally, the system model is established based on the MATLAB. The simulation verifies the feasibility of the method by the operating phase voltage curve and the correctness of the protection impact analysis by comparing the non-working phase current curve with the protection setting.

Power Supply Voltage Dependence of Within-Die Delay Variation of Regular Manual Layout and Irregular Place-and-Route Layout

2011 ◽  
Vol E94-C (6) ◽  
pp. 1072-1075
Author(s):  
Tadashi YASUFUKU ◽  
Yasumi NAKAMURA ◽  
Zhe PIAO ◽  
Makoto TAKAMIYA ◽  
Takayasu SAKURAI
Keyword(s):  
Power Supply ◽  
Voltage Dependence ◽  
Supply Voltage ◽  
Power Supply Voltage ◽  
Place And Route ◽  
Delay Variation

Power Supply Voltage Control for Eliminating Overkills and Underkills in Delay Fault Testing

2016 ◽  
Vol E99.C (10) ◽  
pp. 1219-1225
Author(s):  
Masahiro ISHIDA ◽  
Toru NAKURA ◽  
Takashi KUSAKA ◽  
Satoshi KOMATSU ◽  
Kunihiro ASADA
Keyword(s):  
Power Supply ◽  
Supply Voltage ◽  
Voltage Control ◽  
Fault Testing ◽  
Power Supply Voltage ◽  
Delay Fault ◽  
Delay Fault Testing

AlInAs/GaInAs on InP HEMTs for low power supply voltage operation of high power-added efficiency microwave amplifiers

1993 ◽  
Vol 29 (15) ◽  
pp. 1324 ◽  
Author(s):  
L.E. Larson ◽  
M.M. Matloubian ◽  
J.J. Brown ◽  
A.S. Brown ◽  
M. Thompson ◽  
...  
Keyword(s):  
Low Power ◽  
High Power ◽  
Power Supply ◽  
Supply Voltage ◽  
Power Supply Voltage ◽  
Power Added Efficiency ◽  
Microwave Amplifiers

Design of the variable frequency oscillator in DC-DC converter

Circuit World ◽  
2019 ◽  
Vol 45 (2) ◽  
pp. 80-85
Author(s):  
Tian Lei ◽  
Nan Gong ◽  
Li Wang ◽  
Qin Qin Li ◽  
Heng Wei Wang
Keyword(s):  
Supply Voltage ◽  
Operating Frequency ◽  
Maximum Deviation ◽  
Variable Frequency ◽  
Cmos Process ◽  
Power Supply Voltage ◽  
Output Stage ◽  
Content Type ◽  
Oscillator Frequency ◽  
Light Load

Purpose Because of the logic delay in the converter, the minimum turn on time of the switch is influenced by the constant time. When the inductor current gets to the threshold of the chip, the control signal will delay for a period. This makes the inductor current rising with the increasing of the clock and leads to the load current out of control. Thus, this paper aims to design an oscillator with a variable frequency protection function. Design/methodology/approach This paper presents an oscillator with the reducing frequency applied in the DC-DC converter. When the converter works normally, the operating frequency of the oscillator is 1.5 MHz. So the inductor current has enough time to decay and prevent the power transistor damaging. After the abnormal condition, the converter returns to the normal operating mode automatically. Findings Based on 0.5 µm CMOS process, simulated by the HSPICE, the simulation results shows that the frequency of the oscillator linearly decreases from 1.5 MHz to 380 KHz when the feedback voltage less than 0.2 V. The maximum deviation of the oscillator frequency is only 6 per cent from −50°C to 125°C within the power supply voltage of 2.7-5.5 V. Originality/value When the light load occurs at the output stage, the oscillator frequency will decrease as the load voltage drops. The test results shows that when the circuit works in the normal condition, the oscillator frequency is 1.5 MHz. When the load decreased, the operating frequency is dropped dramatically.

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