scholarly journals Advanced Fast Large Current Electronic Breaker Using Integration of Surge Current Suppression and Current Divider Sensing Methods

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
Hsiung-Cheng Lin ◽  
Heng-Chuan Zo ◽  
Bo-Rong He
Keyword(s):  
Short Circuit ◽  
Negative Temperature ◽  
Threshold Value ◽  
Maximum Load ◽  
Load Current ◽  
Large Current ◽  
Ac Power ◽  
Voltage Signal ◽  
Current Divider ◽  
Surge Current

Electronic breakers or fuses are most widely used tools to protect the electric-driven facilities from overload or short circuit. However, they may suffer from two major drawbacks: (1) it normally takes more than 0.1 s to react, resulting in facilities not sufficiently protected, and (2) a higher rating size of breakers or fuses is demanded than expected due to lack of a surge current suppression mechanism. To overcome these problems, this paper proposes a fast large current electronic breaker based on the integration of current divider sensing and surge suppressing methods. The load surge current can be effectively suppressed by series negative temperature coefficient (NTC) thermistors. The load current is then divided into a small portion and converted to a voltage signal for amplification and comparison with the predefined threshold value, i.e., the maximum load tolerance current. AC power will be disconnected immediately by the switching circuit once the load current exceeds the tolerance value. The disconnection of power supply will continue for a period of time set by the timer. The experimental results verify that the proposed electronic breaker can provide a large load current protection up to 20 A under effective surge suppression within 10 ms.

Taming the Load Current of Identical Cells in Matrix

2021 ◽  
Vol 03 (04) ◽  
Author(s):  
Seok-In Hong
Keyword(s):  
Short Circuit ◽  
Maximum Load ◽  
Load Resistance ◽  
Relative Magnitude ◽  
Internal Resistance ◽  
Rectangular Array ◽  
Load Current ◽  
The Matrix ◽  
In Series ◽  
Fractional Function

We explore the load current [Formula: see text] for a rectangular array (matrix) of [Formula: see text] identical cells where [Formula: see text] strings (columns) of [Formula: see text] serial cells (rows) are arrayed in parallel. [Formula: see text] is equal to [Formula: see text] with the internal resistance of the cell and the load resistance exchanged. By treating a linear fractional function as a translated inversely-proportional function, we can easily capture the properties of [Formula: see text] and the relative magnitude of [Formula: see text] and [Formula: see text] via their ratio. The limiting behaviors of the load current are discussed beyond the ideal-cell and short-circuit limits. For the given total number of cells, we graphically verify the recent findings on the matrix of cells that produces the maximum load current. Finally, we analyze the possibility of a car starting with lemon cells or AA dry cells in matrix. This work would be useful in creating a high school or university curriculum that unifies identical cells in series, parallel, or matrix.

scholarly journals Simulation Model and State Analysis of Ship Transmission Line

2018 ◽  
Vol 25 (s3) ◽  
pp. 36-42
Author(s):  
Yanzhe Hu ◽  
Mengjie Xu ◽  
Yang Li
Keyword(s):  
Transmission Line ◽  
Simulation Model ◽  
Normal State ◽  
Short Circuit ◽  
The State ◽  
Sudden Increase ◽  
Line System ◽  
Voltage Signal ◽  
Fault State ◽  
Sudden Load

Abstract In order to discuss the simulation model of the ship transmission line and the state of the transmission line, an early fault model is built according to the evolution principle of the short circuit fault of the transmission line and combining with the fault characteristics of the early fault. A small distributed ship transmission line system is built in MATLAB/ Simulink. Then, combined with the constructed fault module, the original short circuit module, and the load module, the various states (normal state, early fault state, severe early fault state, short circuit state) of the ship transmission line are stimulated, and the features of voltage signal in each state is analysed. It is concluded that, due to the normal operation of the ship transmission line system, the variation characteristics of the flow signal and voltage signal caused by the sudden load mutation, that is, the sudden load and the sudden increase load, are very similar to the changes caused by the early fault. Therefore, in order to find a more accurate early fault detection method, the state is divided into normal state, sudden load state, sudden increase and sudden decrease load state.

ENGINEERING ANALYSIS OF THE THREE-PHASE SHORT CIRCUIT MODE IN THE 10 KV ELECTRIC NETWORK TAKING INTO ACCOUNT THE INFLUENCE OF LOAD CURRENTS

2021 ◽  
pp. 74-83
Author(s):  
YURI D. VOLCHKOV ◽  
Keyword(s):  
Remote Monitoring ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Load Current ◽  
Electric Network ◽  
Operating Modes ◽  
Three Phase ◽  
Feed Network ◽  
Short Circuits ◽  
Switching Devices

Abstract. The load current aff ects the value of the short-circuit current in the electric network and, consequently, the voltage value. In some cases, this infl uence must be taken into account for the correct choice of switching devices, remote monitoring the operating modes of electric networks, and determining the modes. It is possible to disconnect loads connected through magnetic starters and contactors. Failure to consider the infl uence of the load current can lead to an incorrect interpretation of the identifi ed grid operating modes during remote monitoring and, as a result, incorrect dispatcher’s decisions. In addition, it is also insuffi cient to specify the choice of switching devices in the 10 kV feed network. The article describes a method for analyzing the three-phase short circuit mode in a 10 kV feed network, taking into account the infl uence of load currents. The method is exemplifi ed by the case of an actual electric network – the 10 kV ring feed network containing reclosers and receiving power from diff erent sections of lowvoltage buses of the “Kulikovskaya” 110/35/10 kV substation, belonging to the Branch of PJSC «DGC of Center”-“Orelenergo.” For this network, the values of the three-phase short-circuit currents at points with diff erent distances from the substation buses have been determined. The authors have fi guredout the values of the load currents and their shares in the total short-circuit current. The voltage values at different points of the network in the case of short circuits have also been determined. The research proves that the effect of the load current on the total short-circuit current should be taken into account for the case of remote short circuits.

The Design of Marine 24 V DC Uninterruptible Power Supply

2014 ◽  
Vol 536-537 ◽  
pp. 1537-1541
Author(s):  
Juan Xiao
Keyword(s):  
Power Supply ◽  
Short Circuit ◽  
Battery Management ◽  
Single Chip ◽  
Uninterruptible Power Supply ◽  
Management Scheme ◽  
Ac Power ◽  
Actual Use ◽  
Emergency Power ◽  
Uninterruptible Power

A marine DC uninterruptible power supply is designed. The UPS adopts PIC16C73 single-chip microcomputer to realize the battery management. Both AC power and battery power, the output voltage stability in 23 to 24 v.Via advanced battery management, two sections of charging, equalized charging and floating charging can automatic convert and the DCUPS has many functions of protection, such as over-voltage protection ,under voltage protection and short circuit protection.The actual use on the ship and other occasions showed that the DCUPS is convenient and practical,and is more simple, reliable and longer emergency power supply than the traditional AC-DC uninterruptible power supply management scheme.

A Three-Stage Coarse-Fine-Tuning Analog-Assisted Digital LDO

2020 ◽  
pp. 2150047
Author(s):  
Lianxi Liu ◽  
Yiwei Chen ◽  
Xufeng Liao ◽  
Junchao Mu ◽  
Yintang Yang
Keyword(s):  
Output Voltage ◽  
Maximum Load ◽  
Input Voltage ◽  
Fine Tuning ◽  
Cmos Process ◽  
Load Current ◽  
Input Range ◽  
Low Dropout Regulator ◽  
Layout Area ◽  
Two Stages

This paper proposes a three-stage coarse-fine-tuning analog-assisted digital low dropout regulator (AAD-LDO) without digital ripple. The digital regulation consists of two stages, which break the accuracy-speed-power trade-off. To further improve transient response, a step-variable counter used in the first stage is designed, which makes sure that the output current can track the load current rapidly. The ripple caused by the digital regulation disappears due to the existence of the analog-assistant stage (in the proposed AAD-LDO). As a result, the AAD-LDO achieves the output voltage with high accuracy. Designed in a 0.18[Formula: see text][Formula: see text]m CMOS process, the proposed AAD-LDO has a layout area of 0.133[Formula: see text]mm. For the input range of 1.2–1.8[Formula: see text]V, the output voltage is 1[Formula: see text]V. The maximum load current is 10[Formula: see text]mA at the input voltage of 1.2[Formula: see text]V. The linear regulation and load regulation are 0.061[Formula: see text]mV/V and 0.0082[Formula: see text]mV/mA, respectively. The over/undershoot is suppressed effectively for a 9.5[Formula: see text]mA load step. The peak current efficiency is 99.78%.

A Novel Algorithm for a Single-Phase Active Power Filter

2015 ◽  
Vol 764-765 ◽  
pp. 448-452
Author(s):  
Maoh Chin Jiang ◽  
Bing Jyun Shih
Keyword(s):  
Single Phase ◽  
Active Power Filter ◽  
Active Power ◽  
Nonlinear Loads ◽  
Load Current ◽  
Power Filter ◽  
Sinusoidal Waveform ◽  
Voltage Signal ◽  
Main Voltage ◽  
Novel Algorithm

A novel algorithm for a single-phase active power filter (APF) is proposed in this paper. The proposed algorithm avoids the use of main voltage signal in the calculation of reference compensation current. Therefore, the mains current after compensation is still a pure sinusoidal waveform even when the mains voltage is distorted. A novel circuit for detecting the amplitude of the real part of the fundamental load current is not more than 1/4 cycle. Its transient response is superior to the other conventional techniques. In addition, the proposed algorithm can compensate for the power factor and suppress the harmonics of nonlinear loads. Finally, some experimental results are presented for verification.

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