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Increasing the reliability of the protection of electrical networks as a way to increase the reliability of power supply to consumers
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References:
1. URL: https://en.wikipedia.org/wiki/Bologna_Process
2. Калиниа В. Н. Теория вероятностей и математическая статистика. Учебник для академического бакалавриата. - Лит. Рес.: ЮРАЙТ. - 2015. - 473 с.
3. Mazur D. R. Combinatorics: A Guided Tour. - USA: Mathematical Association of Amerika. - 2010. - 391 p.
4. URL: https://msdn.microsoft.com/library/f7s023d2(v=vs.90).aspx
DOI: http://dx.doi.org/10.20534/ESR-17-3.4-97-99
Zhalilov Rashid, Ph. D. associate professor, Bukhara engineering-technological institute, Uzbekistan department of electrical engineering E-mail: Zhalilov.rashid@mail.ru Safarov Alisher Bekmurodovich, assistant, Bukhara engineering-technological institute, Uzbekistan, department of electrical engineering E-mail: safarov.ali91@mail.ru
Increasing the reliability of the protection of electrical networks as a way to increase the reliability of power supply to consumers
Abstract: Article is devoted to the research of reliability of systems of power supply. Results of introduction of the latest technical solutions realized in automatic Master pact breakers of the Schneider Electric company are given in it, for modernization of 0.4 kV of traditional devices of relay protection applied now in networks. With objective of reduction conformity to modern safety requirements under standards of International Electric-technical Commission it is offered to apply these achievements at the organization of a domestic production on release of power automatic breakers.
Keywords: Master pact, compact, low-voltage automatic breakers.
I. Introduction technical Commission (IEC) is offered use these achievements
For the reason adductions in correspondence to the mod- at organizations domestic production on issue of the power au-ern requirements to safety on standard International Electric- tomatic breakers.
Section 9. Technical sciences
It agrees taken effect on January 1, 2003 (in Russia) to new requirements of Rules of device of electrical installations (RDEI) [1, 13-14], concerning an electrical security and the rules corresponding to the international norms, one of the major requirements to protective equipment in networks to 1000 V is the requirement for ensuring speed of shutdown of the damages connected with impact on the person. This time according to table 1.7.1 of RDEI, depends on value of a voltage and at the phase voltage 220 V should not exceed 0.4 sec.
At present the begun transition in abroad and in Russia to the next generation of microprocessor (digital) device of relay protection and automatics (DRPA) with integration within the limits of a uniform information complex of functions of relay protection, measurement and commercial account electric power, regulation and management of electrical installation it is directed on maintenance of increase of reliability of electrical supply of consumers and conformity to modern safety requirements on IEC [2, 22-25].
The spectrum of arrangements DRPA for networks of the low and average voltage, offered to the consumer the domestic and foreign companies, allows executing adequate systems of protection for various objects.
Digital terminals possess all standard functions of microprocessor protections: measurements, relay protection, system automatics, self-diagnostics, diagnostics of work of the breakers device and a network, digital oscillography and have communication with system of the MANAGEMENT information system on interface RS-485 c open report MODBUS. The given arrangements have a modular design and program formation of protection.
In descriptions on digital relays as well in standard IEEE, IEC time current characteristics current protection are set by mathematical formulas. For construction of these characteristics with objective of their coordination with characteristics of other protective devices (the relay and fuses) is necessary to know the basic traditional conditions of a choice maximal current protection (currents of operation, characteristics, time of operation).
The comparative analysis of different types independent current characteristics of digital relays and Russian analog relays PTB-I, II, III, PT-80 as well as current characteristics of the Russian fuses of type SDQCL (safety device quartz current limiting) has shown, that in the majority of cases the most suitable for Russia is «standard independent», or «normal» the characteristics and to it similar characteristics of standards IEEE (it is moderate independent) and IEC (independent). However there can be an indispensability of use and other types of characteristics.
The known electrical technical firm « Schneider Electric» lets out and delivers on the market various electric equipment and including microprocessor (digital) relays-terminals ofset SEPAM, as well as low-voltage automatic breakers (AB) to set Compact and Master pact. Master pact is one ofthe best AB on greater currents in the world [3, 14-17]. Having improved base model, the company «Schneider Electric» has let out on the market breakers Master pact NT and NW under trade mark Merlin Gerin. To the basic dignity ofpower breakers ofpossibility enable, selectivity and to convenience service — the built in functions of communication and measurements have increased.
The block of the control and management of Micro logic A/P/H is equipped by the liquid crystal display and simple navigating keys. The user has a direct access to necessary parameters and set point. Navigation between screens is carried out intuitively; adjustment is simplified at maximum by direct reading from with display. The text information is displayed on chosen language (from possible 6 languages).
AB Master pact is integrated into the general system of scheduling that optimizes its operational service. The architecture of system of data transmission is characterized by openness and may be adapted for any reports.
Protection functions are independent of the measurement. These functions are controlled by the electronic element of the ASIC common to all units and control that ensures immunity to immunity to interference, as well as a very high reliability [4, 12-16].
The patented system «double regulation» system protection lets you give:
- upper threshold by means of breakers;
- more precise setting by using the keypad or remotely. Such accurate adjust set points (before 1 Ampere) and extracts the time (before 1 second) appears on the display.
Another difference is their environmental security, AB Master pact represent a potential danger to the environmental, factories producing this apparatus, do not pollute the environmental and are in accordance with ISO 14001.
Fig. 1 below shows the Master pact driver performance, AB established in cell developed by the author distributing device -DD-0.4 kV for complete transformer substation (CTS). In coordination with the Master pact (the regulation IDMTL) with protection of the average voltage or fuse is optimized by adjusting the curve of the overload protection. This regulation also provides better adapted this protection to some consumers.
In three-polar automatic breakers Masterpact are neutral protection setting with keyboard or remote (with additional function communication COM) and provides 4 positions: unsecure neutral (4P 3d), partially protected neutral (4P 3d+N/2), fully protected neutral (4P 4d), double protected neutral (4P 3d+2N). Dual neutral protection applies if the neutral section is twice cross- section of phases (a strong asymmetry of load, high late of third order harmonics).
In four pole automatic breakers Master pact are neutral protection setting with keyboard realized with three-terminal section switch and has three positions: unsecure neutral (4P 3d), partially protected neutral (4P 3d+N/2), fully protected neutral (4P 4d). Neutral protection not activated, if the curve overload protection is regulated by one of the protections IDMTL.
In accordance with the current setting and time adjustable from keypad or remotely if there are additional function communication COM, blocks of Micro logic P/H control current, voltage, power, frequency and phase rotation. If there are additional functions for each set point is exceeded COM remotely. Each exceeding the set points can be optionally unhooking (protection) or to the, alarm by additional programmable contact M2C, M6C when you unhooking the memorization is current, ten recent unhooking and emergency signals are recorded in two separate chronological reports. Three — service indicators (wear contact, number of contacts, etc.) are stored in the register.
The additional function communication COM provides:
- read data and remote parameter setting protection or emergency-preventive signalizing;
- the transfer of all measurement data and calculated factors;
- the signalizing of the reasons of the unhooking and emergency-preventive signalizing;
- viewing chronological reports and indicator of the technical service;
- reset counters maximum values.
Some of the measured or calculated values are available only if you have additional function communication COM:
- Ishock./V (I1 + I2 + I3)/3, I no balance;
The Amudarya river basin water resources management issues: case study
- load factor from I ;
- total power factor cos 9. And with block Micro logic H further available:
- total value of the phase and power factor cos 9;
- the harmonic distortion on current and voltage;
- coefficient of current K and average to K;
- intensified coefficients of current and voltage;
- all basic components of harmonics on each phase;
- phase shift the main components of the current and voltage harmonics;
- power and distortion coefficients on each phase;
- amplitude and phase shift 3-51 order harmonics current and voltage.
Access to all counters for the maximum and minimum values is provided if there are additional data transfer functions for COM dispatch system.
The Master pact circuit (2, 5, 6, 7-performances) to protect the mains leads are implemented:
- protection against overloading, triggered by the current value of the current. Thermal memory: thermal "image» before and after the trip.
- Protection against short circuits - selective circuits (MCP) and the instantaneous current cutoff. Select the state function I 2t (enabled or disabled) in setting time protection with low exposure time.
Blocks of the control and management Micro logic 6, 7th performance also include:
- protection against short-circuits- protection type "No balance" or "return of current in accordance with current earth lead" (fig.2). Select the State function I 2t (enabled or disabled) in the setting time;
- but block of the control and management Micro logic 7th performances:
- differential current protection of zero sequence (Vigi).
References:
1. The Rules of the device of electrical installations. The seventh edition. Section 1. Chapter 1.7. // - Moscow: Power Service, - 2006. - P. 439.
2. Solovyov A. L. Guidelines on choice of features and setting protection of electrical equipment with the use of microprocessor terminal to series Sepam manufactured by Schneider Electric. // St. Petersburg Institute of energy development of management and specialists of the Ministry of the Russian Federation, - 2005. - P. 69.
3. Zhalilov R. B. Digital relays: regulatory framework application, brief description // Chief power engineer, - 2007. - P. 14-17. April.
4. Merlin Gerin. Circuit breakers and disconnectors for power transfer in low voltage networks. - 2007 catalog. - Moscow. Informational support center.
5. Zhalilov R. B. About one way of protecting consumers of electricity in the networks of 0.4 kV // Electrical equipment, - 2008. - P. 29-35, February.
DOI: http://dx.doi.org/10.20534/ESR-17-3.4-99-102
Ikramova Malika,
Scientific Research Institute of Irrigation and Water Problems
Akhmedkhodjaeva Ifoda, Khodjiev Alisher, Tashkent Institute of Irrigation and Melioration E-mail: malika.ikramova56@gmail.com
The Amudarya river basin water resources management issues: case study
Abstract: The Amudarya is one of the main water resources involving all Central Asian countries and playing a key role in their development. The most recent period ofwater scarcity is impacting negatively on the socio-economics of the region. Water deficit is bound to increase, especially in the light of climate change and by increases in the demand for food production. In the paper currant water availability state is analyzed.
Keywords: River basin, water resources management, reservoir sedimentation, water loss
Introduction
The Amudarya runoff is mainly generated within Tajikistan (72,8%) and partly in Afghanistan and Uzbekistan (Fig.1). However, water consumption by the riparians is not divided according to their share of generation which is a potential cause of conflict of interests for these countries.
The fate of the river runoff depends on human demands. In reality the entire hydrological cycle and water quality have been changed due to interaction between the river and the territories which is characterized, on the one hand, by water withdrawal for human consumption, industrial and irrigation water require-
ments all of which have a rising trend and, on the other, by the return of water to the river containing pollutants.
At the present time the runoff is controlled by two main reservoirs (the Nurek and the Tuyamuyun) and by several intersystem reservoirs which play an important role in seasonal water storage.
The problems arising in the basin are connected to the development of hydropower in the upper region, increasing water demands, pollution and water losses. The ecological crisis in the region is intensifying and increasing social problems in the Aral Sea region, mainly due to the imperfect water management.
