scholarly journals Study of Testing on Transformers and its Significance

Author(s):  
Ramesh Kumar Patel ◽  
Madhu Upadhyay

Transformers make up the main electrical network of the equipment. Failure of a transformer leads to loss of income and affects the reliability of the power supply for consumers. In order to ensure long and trouble-free operation of the transformers, various diagnostic tests are performed and corrective actions are initiated throughout their lifetime. There are many methods to access the residual life of transformers, for example short circuit tests on transformers and areas of application.

Author(s):  
Nadezhda M. Drey ◽  
Ayrat G. Ziganshin ◽  
Georgi M. Mikheev

In the power supply system of industrial enterprises with low installed capacity, a battery of cosine capacitors is used as reactive power compensation devices in most cases. However, in certain modes of operation in such a network due to the presence of electrical receivers, which generate the highest harmonics, there may be resonance phenomena. Therefore, in such a network you should know both the presence of harmonic components and their percentage. It is known that according to GOST 32144-2013 it is necessary to take into account not only the individual harmonic components of the voltage of about 40 harmonics, but also the total ratio of these components. For this reason, the calculation of this parameter in the power supply system of consumers is an urgent task. In this paper the principle of structure of the three-dimensional graph of the total factor of harmonic components of voltage is revealed. The arguments for the dependence of this factor on the most important parameters of the electrical network, such as system short-circuit power, capacitor bank, load consumption are given. The authors have developed an algorithm for creating a three-dimensional graph of the total harmonic voltage components coefficient with the disclosure of the principles of its construction. As an example, the paper presents graphical dependencies: kU = f(SКZ , QBK ); kU = f(SКZ , PNG ); kU = f(QBK , PNG).


2019 ◽  
Vol 5 (5) ◽  
pp. 19-23
Author(s):  
Leonid A. GERMAN ◽  
◽  
Alexandr S. SEREBRYAKOV ◽  
Aleksey B. LOSKUTOV ◽  
Vladimir L. OSOKIN ◽  
...  

Author(s):  
Xin Shen ◽  
Hongchun Shu ◽  
Min Cao ◽  
Nan Pan ◽  
Junbin Qian

In distribution networks with distributed power supplies, distributed power supplies can also be used as backup power sources to support the grid. If a distribution network contains multiple distributed power sources, the distribution network becomes a complex power grid with multiple power supplies. When a short-circuit fault occurs at a certain point on the power distribution network, the size, direction and duration of the short-circuit current are no longer single due to the existence of distributed power, and will vary with the location and capacity of the distributed power supply system. The change, in turn, affects the current in the grid, resulting in the generation and propagation of additional current. This power grid of power electronics will cause problems such as excessive standard mis-operation, abnormal heating of the converter and component burnout, and communication system failure. It is of great and practical significance to study the influence of distributed power in distributed power distribution networks.


2020 ◽  
Vol 23 (2) ◽  
pp. 52-58
Author(s):  
S. SKRYPNYK ◽  

Our world with its high technologies has long been deeply dependent on the quality of electricity supply. In most countries of the world there are national power grids that combine the entire set of generating capacity and loads. This network provides the operation of household appliances, lighting, heating, refrigeration, air conditioning and transport, as well as the functioning of the state apparatus, industry, finance, trade, health services and utilities across the country. Without this utility, namely electricity, the modern world simply could not live at its current pace. Sophisticated technological improvements are firmly rooted in our lives and workplaces, and with the advent of e-commerce began the process of continuous transformation of the way individuals interact with the rest of the world. But with the achievement of intelligent technologies, an uninterrupted power supply is required, the parameters of which exactly meet the established standards. These standards maintain our energy security and create a reliable power system, that is maintaining the system in a trouble-free state. Overvoltage is the deviation of the rated voltage from the value of the corresponding quality standard (frequency, sinusoidal voltage and compliance of harmonics). Overvoltage in terms of fire hazard is one of the most dangerous emergency modes of electrical equipment, which causes conditions that in most cases are sufficient for the occurrence of fire hazards (exceeding the allowable voltage leads to disruption of normal operation or possible ignition). Against the background of deteriorating engineering systems, increased power consumption and poor maintenance, power supply of electrical installations, the main causes of overvoltage in electrical networks are thunderstorms (atmospheric overvoltage), switching switches, uneven phase load in electrical networks, etc. The physical picture of internal overvoltage is due to oscillatory transients from the initial to the established voltage distributions in the conductive sections due to the different situation in the electrical circuit. In the conditions of operation of electric networks planned, mode or emergency situations are possible. Therefore, the ranges of overvoltage are determined by the range from several hundred volts to tens and hundreds of kilovolts, and depend on the types of overvoltage. Atmospheric overvoltage is considered to be one of the most dangerous types of emergency modes of operation of the electrical network. This overvoltage occurs as a result of lightning discharge during precipitation by concentrating electricity on the surface of the object, the introduction of potential through engineering networks and


Author(s):  
Sergey V. Belyaev ◽  
Aleksey V. Malafeev ◽  
Evgeniy Ya. Omelchenko

To ensure uninterrupted power supply to consumers, maintenance of the electrical networks in a working condition is today carried out through the use of a system of preventive maintenance. In the general case such a system allows building equipment repair schedules based on repair cycles for a long time predetermining the list of necessary material and labor resources in advance. However, in practice, the use of this system is rather difficult and not always effective. This is due to the need to change the repair schedule for emergency or urgent repairs taking into account the seasonality of work performed and the organizational structure of the production department of electrical networks and related departments as well as taking into account the specific features of the operation of specific equipment. Taking into account the current pace of development of electrical networks with a steady increase in the number of consumers (which also leads to a complication of the configuration of electrical networks) this is impossible without the use of appropriate mathematics and software that automates the planning processes for the maintenance and repair of electrical networks with a large number of factors. The minimum equipment downtime was taken as the main criterion for optimality, as a factor that largely determines the reliability of power supply. A planning algorithm has been developed that takes into account the ranking of works in order of importance, the possibility of their shift in time and the likely adjustment of the schedule based on the results of assessing the technical condition of the equipment. A method for minimizing the downtime of repair crews by using them in adjacent areas as well as a technique for identifying a set of equipment that may be under repair in the same period of time are proposed.


2021 ◽  
pp. 75-86
Author(s):  
A. Gai ◽  
◽  
V. Gulevich ◽  

Today, the electricity supplier is not able to declare the possible level of quality of electricity supply, and the consumer simply does not have the opportunity to buy such "high-quality" electricity. In such conditions, a differentiated approach to tariff formation is inevitable, which has been implemented in practice today, albeit in its infancy. Further improvement of the tariff-forming mechanism is impossible without creating a "flexible" dependence of the tariff on the quality indicators of the consumer's power supply. Quality indicators, in turn, are based, on the one hand, on the methods and approaches for their determination, and on the other, on statistically reliable data on the elements that make up the equipment in the "generation-consumer" chain. In recent years, there has been a tendency to change the concept of development of the electric power industry, since preference is given to the development of sources of distributed generation. Distributed generation is understood as a source of electrical energy directly connected to the distribution electrical network or connected to it by consumers. Ensuring the socio-economic stability of society and a decent quality of life for the population largely depends on the reliability and efficiency of the functioning of the infrastructure for the supply of fuel and energy resources, in particular, electricity. Excessive losses of electricity during its production, transportation and distribution, as well as an unacceptable level of harmful emissions into the atmosphere, are the cause of interruptions in power supply to consumers and even the threat of systemic accidents in the United Energy System (UPS) of the country. The introduction of alternative energy sources in electric power systems, in addition to reducing the harmful impact on the environment and solving the problems associated with waste pollution during electric power generation, will reduce the use of natural resources and relieve the backbone and distribution power lines. As part of the scientific search, an approach was proposed, which is the basis for calculations to determine the optimal installation locations for sources of distributed generation of an average overhead line. The results obtained are presented in the framework of a joint technical meeting of leading specialists of operating enterprises, the customer and the staff of the Department of Power Supply named after V.M. Sinkova NULES of Ukraine.


2014 ◽  
Vol 536-537 ◽  
pp. 1537-1541
Author(s):  
Juan Xiao

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.


Sign in / Sign up

Export Citation Format

Share Document