Characteristic Analysis of Ship Transformer Magnetizing Inrush Current and its Suppression Method

2014 ◽  
Vol 1070-1072 ◽  
pp. 1154-1158
Author(s):  
Dong Xiang ◽  
Fei Yu
Keyword(s):  
Low Voltage ◽  
Electric Power System ◽  
Inrush Current ◽  
Characteristic Analysis ◽  
Medium Voltage ◽  
Large Current ◽  
Magnetizing Inrush Current ◽  
Simulation And Experiment ◽  
Suppression Method ◽  
Electrical Apparatus

Medium voltage in the electric power system of ship typically is powered by a large capacity transformer for low voltage electrical apparatus. When switching on, the primary side of transformer will produce very large current, which would endanger the safe operation of power for ships. The mechanism and characteristics of magnetizing inrush current is analyzed when the transformer switches with no load. We think that the reason caused magnetizing inrush current is transformers saturation. Pre-excitation is presented through a small volume transformer magnetizing method of suppressing the inrush current of transformer and validated by simulation and experiment.

The Feasible Analysis of Transformer Fast Reenergizing with Neutral Point Ungrounded

2013 ◽  
Vol 732-733 ◽  
pp. 958-964
Author(s):  
Yao Zhao ◽  
Yu De Yang ◽  
Yan Hong Pan ◽  
Le Qi
Keyword(s):  
High Voltage ◽  
Power Supply ◽  
Low Voltage ◽  
Second Harmonic ◽  
Neutral Point ◽  
Inrush Current ◽  
Differential Protection ◽  
Time Saving ◽  
Magnetizing Inrush Current ◽  
Transformer Differential Protection

The feasibility of transformer fast reenergizing with neutral point ungrounded after the external fault being removed is analyzed in this paper. By calculating overvoltage and discriminating magnetizing inrush current, it analyzes four ways to restore power of transformer and chooses the optimal strategy which is safe and time-saving. The result shows that in the case of transformer neutral point ungrounded, closing the low-voltage circuit side breaker before the high-voltage, which can effectively limit over-voltage in a safe range. The second harmonic characteristic of magnetizing waveform may disappear, while the intermittent angle characteristics are still significant. With the help of the intermittent angle principle, transformer differential protection may not misuse. The average time for each customer interruption is reduced from 40 minutes to 10 minutes and saves an hour for engineer on the way back and forth. It will greatly improve power supply reliability.

An Identification Method of Magnetizing Inrush Current Phenomena in Distribution System

2010 ◽  
Vol 130 (4) ◽  
pp. 430-436 ◽  
Author(s):  
Naoki Dou ◽  
Atushi Toyama ◽  
Kohki Satoh ◽  
Tadashi Naitoh ◽  
Kazuyuki Masaki
Keyword(s):  
Distribution System ◽  
Inrush Current ◽  
Identification Method ◽  
Magnetizing Inrush Current

An Identification Method of Magnetizing Inrush Current Phenomena by Voltage Waveform

2012 ◽  
Vol 132 (6) ◽  
pp. 588-596
Author(s):  
Tadashi Naitoh ◽  
Keiki Takeda ◽  
Atsushi Toyama ◽  
Tatsuhiko Maeda
Keyword(s):  
Inrush Current ◽  
Voltage Waveform ◽  
Identification Method ◽  
Magnetizing Inrush Current

An Improved Identification Method of Magnetizing Inrush Current Phenomena in Distribution System

2012 ◽  
Vol 132 (3) ◽  
pp. 260-267 ◽  
Author(s):  
Tatsuhiko Maeda ◽  
Tadashi Naitoh ◽  
Atsushi Toyama ◽  
Keiki Takeda
Keyword(s):  
Distribution System ◽  
Inrush Current ◽  
Identification Method ◽  
Magnetizing Inrush Current

Evaluation of the Power Transformer Magnetizing Inrush Currents

2020 ◽  
Vol 10 (10) ◽  
pp. 20-32
Author(s):  
Aleksey A. KUVSHINOV ◽  
◽  
Vera V. VAKHNINA ◽  
Aleksey N. CHERNENKO ◽  
◽  
...  
Keyword(s):  
Power Transformer ◽  
Geomagnetic Disturbance ◽  
Inrush Current ◽  
Geomagnetic Disturbances ◽  
Disturbance Intensity ◽  
Magnetizing Inrush Current ◽  
Inrush Currents ◽  
Instantaneous Values ◽  
The Mathematical Model ◽  
Analytical Expressions

The mathematical model of a shell-core power transformer’s magnetization branch is substantiated. By using the model, analytical expressions for the magnetizing current instantaneous values under the conditions of geomagnetic disturbances can be obtained. Quantitative assessments of the magnetizing inrush current amplitudes and durations versus the geomagnetic disturbance intensity are obtained. The dynamics of the power transformer magnetic system saturation transient and changes in the magnetization inrush current amplitudes and durations after a sudden occurrence of geomagnetic disturbances are shown. The error of estimating the magnetizing inrush current amplitudes under geomagnetic disturbances is determined based on comparison with experimental data.

Reduction of the Low Voltage Substation Constraints by Inserting Photovoltaic Systems in Underserved Areas

2019 ◽  
Vol 12 (2) ◽  
pp. 105-112
Author(s):  
Benbouza Naima ◽  
Benfarhi Louiza ◽  
Azoui Boubekeur
Keyword(s):  
Low Voltage ◽  
Voltage Drop ◽  
Electrical Energy ◽  
Utilization Rate ◽  
Photovoltaic Systems ◽  
Voltage Distribution ◽  
Medium Voltage ◽  
Pv Systems ◽  
Transformer Substation ◽  
Load Pattern

Background: The improvement of the voltage in power lines and the respect of the low voltage distribution transformer substations constraints (Transformer utilization rate and Voltage drop) are possible by several means: reinforcement of conductor sections, installation of new MV / LV substations (Medium Voltage (MV), Low Voltage (LV)), etc. Methods: Connection of mini-photovoltaic systems (PV) to the network, or to consumers in underserved areas, is a well-adopted solution to solve the problem of voltage drop and lighten the substation transformer, and at the same time provide clean electrical energy. PV systems can therefore contribute to this solution since they produce energy at the deficit site. Results: This paper presents the improvement of transformer substation constraints, supplying an end of low voltage electrical line, by inserting photovoltaic systems at underserved subscribers. Conclusion: This study is applied to a typical load pattern, specified to the consumers region.

scholarly journals Machine Learning and GIS Approach for Electrical Load Assessment to Increase Distribution Networks Resilience

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4133
Author(s):  
Alessandro Bosisio ◽  
Matteo Moncecchi ◽  
Andrea Morotti ◽  
Marco Merlo
Keyword(s):  
Machine Learning ◽  
Distribution System ◽  
Low Voltage ◽  
Regression Tree ◽  
Distribution Networks ◽  
Machine Learning Algorithms ◽  
Extreme Weather Events ◽  
Medium Voltage ◽  
Weather Events ◽  
Building Area

Currently, distribution system operators (DSOs) are asked to operate distribution grids, managing the rise of the distributed generators (DGs), the rise of the load correlated to heat pump and e-mobility, etc. Nevertheless, they are asked to minimize investments in new sensors and telecommunication links and, consequently, several nodes of the grid are still not monitored and tele-controlled. At the same time, DSOs are asked to improve the network’s resilience, looking for a reduction in the frequency and impact of power outages caused by extreme weather events. The paper presents a machine learning GIS-based approach to estimate a secondary substation’s load profiles, even in those cases where monitoring sensors are not deployed. For this purpose, a large amount of data from different sources has been collected and integrated to describe secondary substation load profiles adequately. Based on real measurements of some secondary substations (medium-voltage to low-voltage interface) given by Unareti, the DSO of Milan, and georeferenced data gathered from open-source databases, unknown secondary substations load profiles are estimated. Three types of machine learning algorithms, regression tree, boosting, and random forest, as well as geographic information system (GIS) information, such as secondary substation locations, building area, types of occupants, etc., are considered to find the most effective approach.

Cascaded Multilevel Inverter IM Speed-Sensorless Vector Control System Based on MRAS Theory

2013 ◽  
Vol 344 ◽  
pp. 159-163
Author(s):  
Zhen Jun Lin ◽  
Sheng Hua Huang
Keyword(s):  
Vector Control ◽  
Induction Motor ◽  
Low Voltage ◽  
Multilevel Inverter ◽  
Speed Sensorless ◽  
Multilevel Inverters ◽  
Sensorless Vector Control ◽  
Simulation And Experiment ◽  
Vector Control System ◽  
Cascaded Multilevel Inverter

Cascaded multilevel inverters could realize high-voltage output based on a series connection of power cells which use standard low-voltage component configurations. This characteristic could achieve high-quality output voltage waveforms and input current waveforms. These merits are made for motor control, especially in the field of speed-sensorless vector control of induction motor based on the theory of MRAS. This paper constructs a simulation system with the help of MATLB/SIMULINK and a system combined cascaded H-bridge multilevel inverter with induction motor with the help of DSP and FPGA. The simulation and experiment results verified the superiority of cascaded multilevel inverter applied on the MRAS speed-sensorless vector control of induction motor.

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