scholarly journals Effective mode of voltage in the electrical network when powering ships of the technical fleet and floating objects from the shore

2021 ◽  
Vol 2131 (5) ◽  
pp. 052005
Author(s):  
Y Denchik ◽  
D Zubanov ◽  
M Romanov

Abstract The article discusses negative consequences of a decrease in the quality of electrical energy when feeding ship receivers of electricity from coastal sources, a method is proposed to ensure an effective voltage regime in the electrical network when feeding ships of technical fleet and floating objects from the coast. Definition of the equilibrium voltage mode at the “shore-to-ship” power supply scheme is given, the equivalent circuit of supply line (feeder) for the river fleet is developed, significant regulatory effects of the “shore-to-ship” power transmission elements are determined. Experimental studies of static characteristics of floating crane of R-99 project have been carried out. According to the results of the experiment, regulating effects on the voltage of the complex load of 0.4 kV of floating crane were determined. A calculation program for personal electronic computers has been compiled, which provides an assessment of the impact of voltage deviations in electrical networks when regulating the load. The law of voltage regulation in the “shore-to-ship” power transmission is proposed. An experimental verification of effectiveness of proposed regulation law was carried out while ensuring the equilibrium mode.

2020 ◽  
Vol 11 ◽  
pp. 96-104
Author(s):  
Abdelkader Rahmouni

The work presented in this paper is a contribution to the problem of controlling the reactive powers and the voltages in an electrical network. Among these control tools, the static reactive power compensator (SVC) has been chosen because of its simplicity of control. The SVC is among the FACTS 'Alternative Flexible Current Transmission Systems' devices that help to deal with problems encountered in the operation of electrical networks either in the distribution side or in the transport side. In this work, the SVC is used to control the reactive power and the voltage in an electric power transmission network. In order to improve its efficiency, three voltage regulation systems have been chosen in the control system of this compensator.


Author(s):  
A. V. Lykin ◽  
E. A. Utkin

The article considers the feasibility of changing the structure of a distribution electrical network by transferring points of electricity transformation as close to consumers as possible. This approach is based on installation of pole-mounted transformer substations (PMTS) near consumer groups and changes the topology of the electrical network. At the same time, for groups of consumers, the configuration of sections of the low-voltage network, including service drops, changes. The efficiency of approaching transformer substations to consumers was estimated by the reduction in electrical energy losses due to the expansion of the high-voltage network. The calculation of electrical losses was carried out according to twenty-four hour consumer demand curve. To estimate the power losses in each section of the electrical network of high and low voltage, the calculated expressions were obtained. For the considered example, the electrical energy losses in the whole network with a modified topology is reduced by about two times, while in a high-voltage network with the same transmitted power, the losses are reduced to a practically insignificant level, and in installed PMTS transformers they increase mainly due to the rise in total idle losses. The payback period of additional capital investments in option with modified topology will be significantly greater if payback is assessed only by saving losses cost. Consequently, the determination of the feasibility of applying this approach should be carried out taking into account such factors as increasing the reliability of electricity supply, improving the quality of electricity, and increasing the power transmission capacity of the main part of electrical network.


2020 ◽  
Vol 178 ◽  
pp. 01068
Author(s):  
I.O. Golikov ◽  
A.V. Vinogradov ◽  
V.E. Bolshev ◽  
A.V. Vinogradova ◽  
M. Jasinski ◽  
...  

This article describes the features of voltage regulation in electrical networks of 35, 110, 220 kV. The structural diagram of the 35/10/0.4 kV network is presented. The paper also describes the adaptive automatic voltage regulation system which allows regulating the voltage taking into account the actual voltage values at the consumers’ inputs. The structural diagram of the adaptive automatic voltage regulation system in the 0.4 kV electrical network using a boost transformer as an additional means of voltage regulation is given. The system is based on voltage sensors installed in different parts of an eletcrical network sending information on voltage values to to the processing unit which generates a signal for voltage regulating supplied to the executive device and the working body whuch, in turn, change the on-load tap-changer position of a transformer. The paper justifies the need for the enhancement of the adaptive automatic voltage regulation system for different voltage classes wich allows controlling a voltage change at different power supply system levels and regulating voltage level in accordance with this change. For this problem the multi-level adaptive automatic voltage regulation systemis proposed. The system allows regulating the voltage not only in the 0.4 kV network but also in networks of higher voltage classes. The proposed system can be integrated into the structure of intelligent electrical networks.


2021 ◽  
Vol 11 (24) ◽  
pp. 11608
Author(s):  
Alina Vinogradova ◽  
Alexander Vinogradov ◽  
Vadim Bolshev ◽  
Andrey Izmailov ◽  
Alexey Dorokhov ◽  
...  

Sectionalizing 0.4 kV power transmission lines (PTL) improves power supply reliability and reduces electricity undersupply through the prevention of energy disconnection of consumers in the event of a short circuit in the power line behind the sectionalizing unit (SU). This research examines the impact of sectionalizing on power supply reliability and reviews the literature on sectionalizing unit allocation strategies in electrical networks. This paper describes the experience of the use of sectionalizing units with listing strengths and weaknesses of adopted technical solutions and describes the new structure of sectionalizing units. A new methodology is proposed, whereby there are two criteria for allocating SU in 0.4 kV power transmission lines. The first criterion is the sensitivity limits against single-phase short circuits used for calculating the maximum distance at which SU can be installed. The second criterion is power supply reliability improvement, evaluating the cost-effectiveness of installing sectionalizing equipment by reducing power supply outage time. The established methodology was put to the test on an actual electrical system (Mezenka village, Orel area, Russia), which demonstrated that the installation of a sectionalizing unit paid off.


2020 ◽  
Vol 1 (57) ◽  
pp. 28-32
Author(s):  
V. Perepecheny

This article presents the results of research on the parameters of electrical networks with a voltage of 6 (10) and 0.38 kV in relation to capital investments. The analysis of existing methods of estimation of parameters before designing for power supply networks in a small town with low load density is carried out. In modern conditions, in the distribution of electrical networks is of paramount importance the introduction of energy-saving schemes and parameters of power supply systems. One of the main ways to implement them is to increase the efficiency of 6-10 / 0.38 kV networks. In the actual design of electrical networks, economic proportionality can not always be maintained for various reasons: the impact of technical constraints, the discreteness of the rated power of transformers and cable crossing scales, a significant deviation of individual capacities of consumers from the average value. In that case there is an increase in the reduced costs. A methodology for determining the optimal power of transformer substations and optimal sections of 0.38 kV power transmission lines is proposed, taking into account the probable nature of the applied load. When assembling the power supply circuit for the optimal form of parameters, voltage, principles of voltage regulation and reactive power compensation. Decisions of this kind are substantiated by technical and economic comparisons of a series of technically acceptable variants of power supply networks. An important measure that facilitates the selection of the most economical option is the assessment of the proposed project, which relates to the selection of the optimal capacity of transformer substation (TS) networks using calculation formulas. The aim of the research was to improve the existing methods on the basis of separate accounting of the reliability coefficient of 0.38 kV and 6-10 kV network. Key words - electric power supply network, network parameters, transformer substation, load density, line wire section, specific load, unit costs, optimum parameter, distribution networks, electric energy.


2021 ◽  
Vol 2131 (5) ◽  
pp. 052047
Author(s):  
Y Denchik ◽  
E Ivanova ◽  
V Salnikov ◽  
S Gorelov ◽  
D Zubanov

Abstract The article deals with topical issues of reducing the asymmetry of linear voltages in the electrical networks of water transport enterprises. Asymmetric modes in the electrical network are researched, which defined the need for automated determination of conductive electromagnetic disturbance. A mathematical description of the occurrence process and strategy for determining the conductive low-frequency electromagnetic disturbance by the voltage asymmetry coefficient in the reverse sequence are presented. The parameters of this coefficient are described: mathematical expectation, standard deviation, probability of occurrence during the calculation period. A mathematical model is obtained that represents a conductive electromagnetic disturbance and explains the probability of its occurrence. A method of automated determination of conductive electromagnetic disturbance has been developed. A software product is presented (certificate of registration No. 2016661752), which allows processing the voltage coefficients obtained as a result of measurements in the reverse sequence. The conductive disturbance is determined for the purpose of suppression and ensuring electromagnetic compatibility. To ensure an effective mode by powering ships from the shore and to increase the efficiency of power transmission, a strategy for voltage symmetry in the electrical network is presented.


2020 ◽  
Vol 220 ◽  
pp. 01005
Author(s):  
V.E. Bolshev ◽  
A.V. Vinogradov ◽  
A.V. Vinogradova ◽  
A.V. Bukreev ◽  
S.R. Khasanov

Sustainable operation of the power grid complex is impossible without reliable and high-quality operation of 10/0.4 kV electrical distribution networks, which are the final link in the system for providing consumers with electric energy and are in direct interaction with a specific consumer. The study of statistical information on the composition of distribution networks makes it possible to draw conclusions about electrical network state, to implement recommendations for their development and to compare distribution electrical networks in different regions. This information is especially relevant for analyzing the reliability of power supply to consumers connected to the considered electrical distribution networks. Such indicators of network structure as the length of electric transmission lines of different voltages and power transmission schemes are studied. It also analyzes the number of damages in networks, the causes of these damages, data on the time of planned and emergency outages. This paper considers the structure of 10/0.4 kV electrical distribution networks located on the territory of one of the districts of the Kaluga region. The sample for distribution networks was: 1190 overhead transmission lines and 536 transformer substations. Consumers in the district are 21671 subscribers of individuals and 1986 subscribers of legal entities, that is, a total of 23657 metering points. On the lines of 0.4 kV and 10 kV, the percentage of their isolated design was revealed. The share of single-transformer and two-transformer versions of transformer substations is analyzed.


Author(s):  
Abdelkader Rahmouni

The work presented in this article is a contribution to the problem of controlling reactive powers and voltages in an electrical network. Among these control tools, the static reactive power compensator (SVC) was chosen because of its simplicity of control. SVC is one of the Alternative Flexible Current Transmission Systems (FACTS) devices which help to solve the problems encountered in the operation of electrical networks, either on the distribution side or on the transport side. To increase its compensation efficiency in the face of harmonic currents which cause voltage distortion, we have introduced a three-phase harmonic filter. This new hybrid SVC is used to control the reactive power, the voltage and in addition to reduce the voltage distortion and the correction of the power factor in the electrical energy transport network. In order to improve its efficiency, two voltage regulation systems have been chosen in the control system for this compensator, the fuzzy PI regulator and the PIP regulator.


Vestnik MEI ◽  
2021 ◽  
pp. 27-36
Author(s):  
Mikhail G. Astashev ◽  
◽  
Artem S. Vanin ◽  
Vladimir M. Korolev ◽  
Dmitriy I. Panfilov ◽  
...  

The article addresses the problem of ensuring permissible voltage levels in distribution electrical networks of various types: distribution networks of large cities, regional distribution electrical networks, and distribution electrical networks containing renewable energy sources. The most typical factors causing the voltage to go beyond the permissible limits specified by the relevant regulatory documents are pointed out. The negative factors conducive to the voltage at the consumer end deviating from the permissible limits, including a long length of network lines, high network load, low controllability of the network, load schedule nonuniformity, and poor observability of the network, are analyzed. The existing principles of voltage control in electrical distribution networks, namely, automatic and seasonal regulation, are studied. A distribution electrical network test model representing a real network fragment is developed. The model operation modes have been verified based on the data of measurements carried out in the original distribution electrical network. The voltage distributions in a medium voltage network during its operation under the conditions of the highest and lowest loads are demonstrated. It is shown, on the test model example, how the network voltage can be controlled by automatically regulating the voltage at the power supply center and selecting a fixed position of the NLTC at 10/0.4 kV transformer substations. It is shown that the use of power transformer OLTCs does not ensure sufficient means for adequately controlling the voltage in networks containing long power lines and featuring highly nonuniform seasonal and daily load schedules. The technical efficiency and economic feasibility of using automatic voltage regulation devices on 10/0.4 kV transformers for local voltage control are analyzed. The economic efficiency of applying automatic voltage regulation devices at 6--10/0.4 kV substations was evaluated in comparison with other means for improving the power distribution network voltage quality by upgrading the 10 kV feeder lines or installing a voltage booster at the inlet to the problematic 10 kV network section. The application field of automatic voltage regulators in the form of semiconductor devices for regulating the transformer output voltage at distribution transformer substations is shown.


2021 ◽  
Vol 1 (4) ◽  
pp. 33-44
Author(s):  
S.E. Senkevich ◽  
◽  
Ye.N. Ilchenko ◽  
I.S. Alekseyev ◽  
◽  
...  

One of the significant factors influencing the operation of the tractor is the unsteady load that occurs when starting off, during the initial period of acceleration and deceleration. The elastic-damping mechanisms are used to reduce the negative consequences of such loads. Scientists still develop and study their application. In this article, the analysis of the cross correlation function and the analysis of the mutual spectral density of two processes were carried out. The analyzed process-es were the engine crankshaft speed and the drive wheel speed. This analysis shows the change in the speed of the passing load frequencies along the shaft line of the traction class 1.4 wheeled trac-tor power transmission, where an elastic-damping mechanism is installed. The studies were carried out for the operating conditions of a tractor with a seeder. The purpose of the study was to deter-mine the effect of the elastic-damping mechanism installed in the power transmission of a tractor on its operation with a trailed seeder. In the general case, the object of research is the functioning of a tractor of traction class 1.4 process, which is located in a unit with a seeder. Analysis of the mutual correlation function of the two processes showed a change in the speed of the passing load frequen-cies along the shaft line. The ratio of the propagation time of the disturbance signal in the experi-mental tractor in relation to the production version along the shaft line when aggregating the tractor with the seeder decreases by 40.1%. The analysis of the mutual spectral density shows a shift in the frequency of disturbing influences in relation to the serial version and a decrease in their value when the tractor is aggregated with a seeder by 33.3%. The value of the mutual spectral density is lower in the experimental version of the tractor, which may mean that the elastic-damping mechanism, as an element of the power transmission, absorbs part of the load fluctuations and reduces their propagation speed along the shaft line.


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