Improving the high-voltage quality of alumina insulators in vacuum by surface doping

1988 ◽  
Vol 23 (1) ◽  
pp. 33-36 ◽  
Author(s):  
H. Brettschneider
Keyword(s):  
High Voltage ◽  
Surface Doping ◽  
Voltage Quality

The Coordinated Control Strategy for Generator-Transformer's Voltage Regulation

2014 ◽  
Vol 960-961 ◽  
pp. 1128-1133
Author(s):  
Yu Ze Zhang ◽  
Wen Ying Liu ◽  
Shu Xin Li ◽  
Wei Zhou Wang ◽  
Fu Chao Liu ◽  
...  
Keyword(s):  
High Voltage ◽  
Control Strategy ◽  
Coordinated Control ◽  
Voltage Regulation ◽  
Medium Size ◽  
Phase Lag ◽  
Auxiliary Power ◽  
Voltage Quality ◽  
Power Load

Nowadays the main electrical wiring in medium-size and large-size thermal power units is mostly unit wiring. In the quarter of small reactive power load, some generators need to work in phase-lag operation during the daytime and in phase-advancement operation at night to meet the demand of voltage quality of their plant’s high-voltage side. This operation, however, will lower the voltage of auxiliary power and do harm to system’s stability. This paper proposes a kind of coordinated control strategy for generator-transformer’s voltage regulation. In this strategy, the main transformer should be on-load tap charger and the controller regulate the generator voltage and transformation ratio simultaneously when needed, thus the voltage quality of both high-voltage side and auxiliary power side can be insured and the generator no longer work in phase-advancement operation. This control strategy can be a meaningful proposal for AVC in smart grid in the future. Simulation result shows the stability and reliability of the proposed control strategy.

An Analysis of On-Bord High-Voltage Converters of Single-Phase Alternating Current with Increased Miroelectric Power Factor

2020 ◽  
Vol 10 (10) ◽  
pp. 44-51
Author(s):  
Yury Yu. SKOROKHOD ◽  
◽  
Sehgey I. VOL’SKIY ◽  
Keyword(s):  
High Voltage ◽  
Single Phase ◽  
Input Current ◽  
Voltage Converter ◽  
Input Unit ◽  
Power Circuit ◽  
Electrical Systems ◽  
Static Converters ◽  
Technical Requirements

The power circuit arrangements of on-board high-voltage static converters fed from a 3000 V AC single-phase network that in the general case produce multi-channel AC and DC output voltages are considered. The basic technical requirements posed to such converters are formulated. The general structural diagram of high-voltage converters with improved electric power consumption quality is given. Possible power circuit arrangements for the high-voltage converter input unit based on single-phase input current correction devices are considered. A classification and criteria for comparative evaluation of the possible power circuit arrangements of these devices are proposed. The information presented in the article will be of interest for specialists engaged in designing on-board electrical systems involving high-voltage converters that must comply with strict requirements for the quality of consumed single-phase input current.

Uticaj solarne elektrane na kvalitet električne energije u niskonaponskoj distributivnoj mreži

2020 ◽  
Vol 22 (1-2) ◽  
pp. 137-144
Author(s):  
Hidajet Salkić ◽  
Amir Softić ◽  
Amer Salkić
Keyword(s):  
Power Quality ◽  
Negative Feedback ◽  
Electricity Market ◽  
Reactive Power ◽  
Electric Power System ◽  
Integrated System ◽  
Distributed Source ◽  
Voltage Quality ◽  
Number Of Customers

The electric power system, as an integrated system for transmission, distribution and consumption of electricity, is one of the most complex technical and economic systems today. Customers affect on the voltage quality of power network, but the network also has an impact on customers. All disturbances in the network can disrupt operation of the network and affect on operation of the customers, as well as reduce the level of efficiency and operation life or even seriously damage network. Number of customers is increasing every day, as well as proportion of customers who generate disturbances in the network and, at the same time, are sensitive to them. These circumstances impose the need for frequent monitoring of the network, so the analysis of power quality is not unjustified cost but extremely important and profitable investment. The quality of electricity, as part of the overall quality supply of electricity customers in deregulated conditions of liberal electricity market becomes significant regulatory parameter for network operators and a significant contracting parameter on the electricity market. Network operators are obliged to establish a system of individual measurements and a system of permanent monitoring of power quality parameters to determine the state and improve the parameters to the standardized level. Technical parameters are determined by the recommendations made at the international level and may, but do not need, be legally binding. Maintaining a certain level of voltage quality at some point of the network is the responsibility of electricity distributor. This task distributor executes by limiting of negative effects of producer/customer to the network. Therefore, each electricity producer/customer is obliged to reduce own negative feedback effects (injection of higher harmonics, taking of reactive power, emissions of flickers and loads unbalances) to a prescribed, prearranged, limited values. There are many norms that describe the quality of electricity, but in Europe the best known is EN50160 (issued by CENLEC). This paper presents the approach to measuring the voltage quality at the point of electricity delivery from distributed source into distribution network from the aspect of limiting the negative feedback of distributed source on the voltage quality.

scholarly journals RESEARCH OF INCREASING THE REACTIVITY COTTON CELLULOSE INTENDED FOR CHEMISTRY

2020 ◽  
Vol 2020 (1) ◽  
pp. 69-75
Author(s):  
R Sayfutdinov ◽  
◽  
U Mukhitdinov ◽  
N Eshpulatov
Keyword(s):  
Labor Productivity ◽  
Electric Charge ◽  
High Voltage ◽  
Reaction Rate ◽  
Cotton Cellulose ◽  
Chemical Processing ◽  
Foreign Countries ◽  
Composition And Structure ◽  
Computer Controlled

The reactivity of cotton pulp during chemical processing is significantly lower compared to celluloses obtained from other cellulose-containing plants. Increasing the reactivity of cotton cellulose improves the quality of the products based on it, and also increases labor productivity. The aim of this work is to study the possibility of replacing wood pulp imported from foreign countries with domestic cotton cellulose by increasing the reactivity of cotton cellulose for chemical processing, improving the quality of the resulting product and increasing the reaction rate. In this work, we used methods for determining the composition and structure of cotton cellulose samples. The reactivity of the obtained samples to acetylation after treatment with electric charges was studied. An increase in reactivity was evaluated by a decrease in crystalline areas based on diffract grams that were recorded on a computer-controlled XRD-6100 apparatus (Shimadzu, Japan). A method is proposed for increasing the reactivity of cotton cellulose by treating it with high voltage electric charges. To reduce the crystalline areas of cotton cellulose, it was activated by an electric charge, which led to an increase in the reactivity of cotton cellulose. The optimal voltage limits are found, the number of pulses and the required capacitance of the capacitor, at which the maximum values of the reactive activity of cotton cellulose are achieved.

scholarly journals Power quality of dual two-level inverter fed open end winding induction motor

2020 ◽  
Vol 18 (2) ◽  
pp. 688
Author(s):  
Hayder Ali Mohamed ◽  
Hanan Mikhael D. Habbi
Keyword(s):  
Induction Motor ◽  
Harmonic Distortion ◽  
Voltage Source ◽  
Current Signal ◽  
Space Vector Pwm ◽  
Dc Voltage ◽  
Common Mode Voltage ◽  
Voltage Quality ◽  
Open End Winding

<p><span>This paper presents the minimization of the total harmonic distortion (THD) of the current signal for open-end winding induction motor by using dual two-level inverter. In order to obtain a good value of THD, the space vector PWM has been used for switching the dual two-level inverter to improve the output voltage quality, gets a low common mode voltage, reduce the execution time, and to save the memory capacity. The proposed scheme uses two different DC voltage source with two two level inverter in order of minimizing the number of components. As well as it is an important to utilize the energy which increases the application of dual inverter in microgrids. All simulation results are obtained using Matlab/Simulink. </span></p>

scholarly journals TO SURVEY POWER QUALITY OF HIGH VOLTAGE KEY-CUSTOMER BY USING VOLTAGE EVENT RECORD

2020 ◽  
Vol 5 (9) ◽  
pp. 30-43
Author(s):  
Yen-Ming Tseng ◽  
Hsi-Shan Huang ◽  
Chen JiQuan ◽  
Wang Xuefei ◽  
Chen Han ◽  
...  
Keyword(s):  
Power Quality ◽  
High Voltage ◽  
Low Voltage ◽  
Economic Losses ◽  
Data Sets ◽  
Event Data ◽  
Voltage Swell ◽  
Event Record ◽  
Key Customer

According to IEEE-1159 definition and classification of power quality of applying at supplyside and demand-side of power system to evaluate the power quality of high voltage keycustomer and using the voltage events record (VER) in low voltage level supply. Which voltage parameter set of VER with specific software Event View software by Fluke and can collect event data, plot graphic of event data sets that can using the data mining skill to analysis the voltage swell, voltage sag, power outage, frequency events and three phase load unbalance of high voltage key-customer. By abnormal voltage event statistics with discriminated by quantization of high voltage key-customer which can evaluate the own power quality and an also provide reference for quality requirements for related semiconductor factories with higher demand that can avoid the significant effect the economic losses.

scholarly journals Uncertainty and Disturbance Estimator Based Controller Equipped With a Multiple-Time-Delayed Filter to Improve the Voltage Quality of Inverters

2019 ◽  
Vol 66 (11) ◽  
pp. 8947-8957 ◽  
Author(s):  
Shlomo Y. Gadelovits ◽  
Dauren Insepov ◽  
Visakan Kadirkamanathan ◽  
Qing-Chang Zhong ◽  
Alon Kuperman
Keyword(s):  
Multiple Time ◽  
Voltage Quality ◽  
Uncertainty And Disturbance Estimator ◽  
Disturbance Estimator

scholarly journals Induction Motor Drives Fed by an NPC Inverter with Unbalanced DC-Link

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1379 ◽  
Author(s):  
Umberto Abronzini ◽  
Ciro Attaianese ◽  
Matilde D’Arpino ◽  
Mauro Di Monaco ◽  
Giuseppe Tomasso
Keyword(s):  
Output Voltage ◽  
Harmonic Distortion ◽  
Voltage Regulation ◽  
Motor Drives ◽  
Operating Conditions ◽  
Switching Frequency ◽  
Voltage Level ◽  
Voltage Quality ◽  
Vector Modulation

Neutral Point Clamped (NPC) converters with n levels are traditionally controlled in such a way that the DC-link capacitors operate at 1/( n - 1) of the total DC-link voltage level. The voltage level across the DC-link capacitors has to be properly regulated by the capacitor unbalance control to contain the harmonic distortion of the converter output voltages. State-of-the-art modulation techniques address the problem of the DC-link voltage regulation for NPC inverters. However, they highly show reduced performance when unbalanced DC-link voltages are considered. In this paper, a novel Space Vector Modulation (SVM) is proposed for NPC converters with an unbalanced DC-link. At every modulation interval, the technique defines the optimal switching pattern by considering the actual unbalanced DC-link conditions. The proposed modulation allows improving the harmonic content of the NPC converter output voltage with respect to a traditional ML-SVM, when the same operating conditions are considered. As an extension, the proposed modulation technique will guarantee the same output voltage quality of a traditional ML-SVM with unbalanced DC-link, while improving the conversion efficiency thanks to a reduction of switching frequency.

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