scholarly journals Power quality and losses in 0.38 kV rural distribution networks

2019 ◽  
Vol 217 ◽  
pp. 01012
Author(s):  
Igor V. Naumov ◽  
Alexander N. Tretiakov ◽  
Marina N. Yakupova ◽  
Elvira G. Fedurinova ◽  
Dmitriy N. Karamov

The guidelines for the design of rural and urban power supply systems do not consider the issues of reactive power compensation and reduction in additional losses due to unbalanced and non-sinusoidal conditions. At the same time, today’s rural power consumers have a great number of non-linear loads in their residential premises. Moreover, the unbalanced phase currents and voltages are an established fact. The paper aims to demonstrate the extent to which power quality and losses vary in real rural 0.38 kV networks. To this end, the objectives were posed to study the operation of two facilities: 1- switchgear at the cottage (with an installed capacity of 15 kW); 2- switchgear at the communal entrance hallway for 60 apartments in an apartment building (with an installed capacity of 75 kW).

2019 ◽  
Vol 114 ◽  
pp. 04006
Author(s):  
Bui Ngoc Hung ◽  
Lidiia I. Kovernikova

Coal mining is one of the important economic sectors in Vietnam. Power supply systems of coal mines and open-cuts are complex. They have multiple levels of voltages and different types of loads. New electrical equipment usually works alongside with the equipment that is obsolete and worn-out. Power supply systems of industrial areas of Vietnam where coal is mined are characterized by the low power quality. In Vietnam the indices which characterize the distortion of both voltage and current waveforms have standard values. The article presents the findings upon the analysis of a power supply system of a coal open-cut in Vietnam and the electrical equipment of the coal sorting plant along with the results of the experimental studies of power quality indices and the non-sinusoidal mode parameters. The measurement analysis has shown that the indices of the 5-th and 7-th harmonics of voltage were over the limits. There are interharmonics in voltages and currents. The article analyzes the characteristics of active filters. It is possible to improve the power quality by using an active filter which generates both reactive power to increase the load power factor and harmonic and interharmonic currents to reduce the degree of voltage and current waveform distortion.


Author(s):  
E. I. Gracheva ◽  
A. N. Gorlov ◽  
Z. M. Shakurova

The article examines the main features of the layout of electrical equipment for shop networks of internal power supply with the definition of indicators for a group of shop customers connected to a single power center, affecting the choice of the structure of schemes for shop network sites. The parameters characterizing the circuit topology are revealed. A study is presented of the influence of the load factor of workshop transformers on their reactive power factor, it is proved by calculation by technical and economic criteria the feasibility of replacing a workshop transformer with two with a lower total power. The calculation of energy savings in the in-plant power supply systems. The type of dependences tgφ of transformers ТМ and ТСЗ with various rated powers in the function of loading transformers is established. The most significant factors of the growth of idle power losses during operation are presented. With determination of losses of active and reactive power and electricity in transformers and losses of active power in a high voltage distribution network A feasibility study was carried out on the options for internal power supply schemes with two transformers of lower power installed instead of one, and the feasibility of such a replacement to increase the efficiency of the equipment was proved and the estimated payback period for the investment capital was determined. A comparative analysis of the studied power supply schemes of industrial enterprises with the identification of their advantages and disadvantages.


2021 ◽  
Vol 1 (42) ◽  
pp. 8-15
Author(s):  
Aleksandr Vinogradov ◽  
◽  
Anatoliy Seyfullin

The construction of intelligent power supply systems for rural consumers (microgrids) is a promising concept for the development of the energy infrastructure of agricultural facilities. In the process of designing and operating micro-networks, a large number of technical, organizational and legal issues arise, the correct answer to which affects on the reliability, quality and efficiency of electricity supply to agricultural facilities. The analysis of the documentation regulating these processes is of particular relevance. (Research purpose) The research purpose is in analyzing the documentation regulating the construction and operation of intelligent power supply microgrid systems for rural consumers. (Materials and methods) The article reviews regulatory documents in the field of regulation of the electric power industry, distributed generation facilities, renewable energy sources, and the functioning of retail electricity markets. Authors used the method of system analysis, methods of comparisons and analogies, and expert assessments. (Results and discussion) The article presents the issues of functioning of micro-networks of rural consumers as part of the power system, in retail electricity markets; implementation of technological connection and integration of micro- networks into distribution networks. Authors evaluated the regulatory and technical documents regulating the general technical requirements for the design and operation of micro-networks. Domestic and foreign standards for the connection and parallel operation of micro-networks with distribution networks as part of the power system and special documents on micro-networks has been studied. (Conclusions) The article proposes measures for the development of GOST R based on the European IEC TS 62898-1 «Microgrids», harmonized with the requirements of Russian standards, taking into account the features of the Russian electric power industry and agriculture. The article notes the need to make changes to the Russian network codes to ensure the integration of rural micro-networks. The measures of state support aimed at stimulating the spread of intelligent power supply systems for rural consumers were cited.


Author(s):  
P. P. Hovorov ◽  
K. V. Hovorova ◽  
А. К. Kindinova ◽  
O. Abdelrahim

Modern power supply and lighting systems of cities are complex electrical systems of an automated type, in which the processes in individual power supply systems and city lighting systems are interconnected and interdependent. Therefore, the search for efficient technologies for the transmission of electrical energy in them is an extremely difficult task. The real state of the power supply and lighting systems in cities today is characterized by low operating efficiency, largely due to the low quality of electrical energy and insufficient compensation of reactive power in them. The mutual influence of power supply and lighting systems in cities, as well as the presence of significant voltage deviations and the overflow of additional reactive power in the networks, causes an increase in voltage and power losses in them, as well as a decrease in the efficiency of networks and connected consumers, in general. Unfortunately, the existing methods and technical means based on them cannot fully solve this problem. The research carried out made it possible to clarify the nature of the processes in the power supply systems and the sanitation of cities and to determine the methods and technical means based on the Smart Grid concept. They are based on the use of phase-shifting booster transformers with an electronic control system. Their use made it possible to provide the possibility of complex control of the voltage modes of active and reactive power with the possibility of installation at any point in the network and centralized control from a single centre. The calculations show that the use of the developed methods and technical means provides an opportunity to reduce power losses in networks by 10–15% and energy costs for consumers by 50–75%.


Sign in / Sign up

Export Citation Format

Share Document