CC BY
19
Siddikov Ilkhomjon, d.t.s., professor, University in Tashkent information technology, Abubakirov Azizjan, Yuldashev Azimjon, Babakhova Gulziba, Assistants, Karakalpak State university in Nukus, E-mail: [email protected] Xonturaev I. M., Mirzoev N. N.,
University in Tashkent information technology
METHODOLOGY OF CALCULATION OF TECHNO-ECONOMIC INDICES OF APPLICATION OF SOURCES OF REACTIVE POWER
Abstract: At present, the sources of reactive power are widely used in telecommunication facilities that have windings (electric motors, transformers, etc.) in the design. To manage these sources, necessary to introduce new technical means and elements, including microprocessor blocks. Combined control of reactive power sources and voltage regulation with the help of a microprocessor-based unit of electric receivers of telecommunication objects turns out to be technical and economical not only for reactive power sources, but also for lowering transformers of the power supply system.
Keywords: telecommunications, electric motors, transformers, reactive power sources, microprocessor control units.
Сиддиков Илхомжон, д.т.н. профессор, Ташкентский информационный технологический университет Абубакиров Азизжан, Юлдашев Азимжон, Бабахова Гулзиба,
Ассистенты, Каракалпакский государственный университет
E-mail: [email protected] Хонтураев И. М., Мирзоев Н. Н.,
Ташкентский информационный технологический университет
МЕТОДИКА РАСЧЕТА ТЕХНИКО-ЭКОНОМИЧЕСКИХ ПОКАЗАТЕЛЕЙ ПРИМЕНЕНИЯ ИСТОЧНИКОВ РЕАКТИВНОЙ МОЩНОСТИ
Аннотация: В настоящее время источники реактивной мощности широко используются в телекоммуникационных объектах с обмотками (электродвигателями, трансформаторами и т. Д.)
В конструкции. Чтобы управлять этими источниками, необходимо ввести новые технические средства и элементы, включая микропроцессорные блоки. Комбинированное управление источниками реактивной мощности и регулированием напряжения с помощью микропроцессорного блока электрических приемников телекоммуникационных объектов оказывается технически и экономичным не только для источников реактивной мощности, но и для снижения трансформаторов системы электропитания.
Ключевые слова: телекоммуникации, электродвигатели, трансформаторы, источники реактивной мощности, микропроцессорные блоки управления.
Introduction
Receivers and converters of electrical energy that have windings in their construction (power converters, transformers, electric motors, etc.) consume not only active power, but also reactive power. By the transmission of electricity through the electrical networks ofthe power supply system (PSS) of reactive power (RP), there are losses of active power in them, for which the consumer has to pay. An alternative to an additional payment for electricity is the installation of reactive power sources (RPS) [1,2].
At most facilities with high-voltage electrical equipment, reactive loads are compensated by overexcitation of existing synchronous compensators (SC) with a high voltage (6-10 kV) or by placing in the electrical network of PSS capacitor units - RPS with high-power (HPC) and low (LPC) voltage [3].
According to carried out analysis, the loss of electricity in the SC, due to the generation of RP by them, is minimal in the operation of electric receivers with a small consumption of RP. The growth of RP output is accompanied by a sharp increase in electricity losses, primarily heating the SC. Studies have also shown that the use of any power, as well as high-voltage SCs with a power below 1600 kV, is uneconomical in low-voltage systems [3, 6, 7].
It should be noted that even with excess RP of highpower high-voltage SCs and generators that allows to observe contractual parameters with the electricity supplier, the consumer is not immune from unjustified losses of the latter. The remark is typical especially for electrical loads with extended high voltage electrical networks and a large number of reducing supply transformers (T) 10 (6)/0.4 kV of PSS objects.
Main part
As experience of operation of electric networks and electric receivers of objects of PSS has shown, cosine
capacitor units are more widespread RPS for them. The power of a reactive power source is proportional to the square of the voltage, frequency and its capacitance [2, 4]:
Qk = U-ffl-C, (1)
where: Qk - reactive power of the capacitor unit;
U2 - voltage of the electrical network TK
© - angular frequency;
C - capacity of the capacitor unit.
The use of embedded microcomputers in a block of microprocessor-based combined automatic control of reactive power sources makes it possible to reduce the breakdown damage of electric and electrical equipment and to improve the quality of generated electricity.
Connection of capacitor units for compensation of reactive power at different voltages of PSS objects is shown in (Fig. 1).
For an example (Fig. 2), we determine the additional losses of the active power AP in T and cable lines of PSS with a length of400 m with a cross section of 50 mm2.
Suppose, before the installation of the LPC at the PSS facility, there were loads:
P = 700 kV Q1 = 500 KVAr S1 = 860 kVA , load factor K31 = 0,86 maximum power loss time: t = 5000 h.
After the installation of the LPC, the load of the PSS facility will have the following values:
Q2 = 100 KVAr S2 = 707 kVA,K32 = 0,707
The current flowing through the electrical networks of the PSS facility is determined as follows:
S, 860 .„ . (2)
I =
1 U^3 (10,5 -1,73) S2 _ 707 US "(10,5-1,73)
12 _
= 47 A;
_ 39 A.
(3)
Figure 1. Scheme of capacitor units for compensation of reactive power at different voltage levels of electrical networks
Figure 2. Scheme of connection of a microprocessor unit for combined control of reactive power sources
Additional power losses in the HV cable:
APK = 3RK ( -122) = 3 ■ 0,248(472 - 392) = 0,52 kV (4)
Additional power losses in T APT of PSS object depend on its load losses: (APK3)
APT = APK3 (( -K322) = 10,6(0,862 -0,7072) = 2,54 kV (5)
Total power losses:
AP = AP„
-APr = 0,52kV + 2,54kV = 3,06kV. (6)
be:
The energy savings for PSS facilities for the year will A3 = AP-t = 3,06• 5000 = 15300 kV• h. (7)
The increase in the capacity of T and the cable lines of PSS objects can be taken into account with corresponding shares of their cost. For power transformer TS:
AKT — KT (Sj — S2) / Sj —
= 500000 • (860 — 707) / 860 — 88953 in total. For cables with a long-lasting current: 1Д = 130A
(8)
AKK = KK (I1 -I2)/I1 = 62000-(47 — 39)/130 = 3815 (9)
Payback period of the LPC:
Tok = (-AKT)/( .ДЭ) =
(160000 - 88953 - 3815) (Ю)
= --7-г-- = 5,7 years
(0,77-15300)
f T0KnuFM
Indicatorofeffectivness = —^^-— -100% =
T
(11)
8 - 5,7
■100% = 28,75%.
V 8 ,
The indicator of the effectiveness of this measure is determined as follows:
Ток норм - Т current norm
Ток - Tok
The connection scheme of the microprocessor-based combined control unit (MBCCU) of the RPS is implemented on the basis of a microcomputer and is presented in (Fig. 2) [4-5].
The developed algorithm and methodology for calculating the technical and economic indicators of the application of the MCU in the RPS application schemes gives a pessimistic payback period for the use of RPS in PSS facilities.
The obtained value ofthe payback period, due to the improvement of the quality of electric power - ensuring the nominal voltage in the power consumption units of the PSS objects (i.e. increasing the service life of electrical equipment, reducing power losses in electrical networks, etc.), actually turns out to be less than its standard value (T ) = 8 years) [2, 6].
v ok nopM/ '
Conclusion
1. The specific value of the HPC is half that of the LPC. However, the constant component of costs for HPC is higher due to the greater cost of connecting them to the electrical networks of PSS objects.
2. The parameters of the regulated LPC - the number and power of the control stages, the power of the unregulated part - are determined by the daily schedule of RPS consumption by electric receivers.
3. Combined control of reactive power sources and voltage regulation with the help of RPS proves to be effective only for LPCs, included in the large inductive resistance of the step-down transformers ofthe PSS obj ects.
4. To change the voltage by one percent of the nominal value it is necessary behind the transformer 1000 kVA, change the RPS to 180 kVAr , behind the transformer 1600 kVA-240 kVAr , behind the cable line 0,38 kV, long 100 m- 240 kVAr, behind the cable line 10 kV 1000m 12500 kVAr long.
According to undertaken studies, the proposed method of selection and application of reactive power sources and microprocessor combined control allows them to reduce by 28.7% the payback period of the implemented technology and the elements of electricity consumption management and to increase the efficiency of energy saving measures implemented in the PSS objects.
References:
1. Allaev K. R.- Energy of the World and Uzbekistan-Tashkent: Molia - 2007.- 388 p.
2. Allaev K. R., Siddikov I. H., Holiddinov I. H., Abdumannonov A. A., Hasanov M. Y. Algorithm for calculation of excess technological power consumption // State Patent Office of RUz. Certificates Nr. 20140089, 17.12.2014.
3. Borodenko V. A. Resource-saving as the main principle of creating power automation devices // Vestnik NIA RK.-M.,- 2006.-No. 2. - 12 c.
4. Regulations on the order of organization of work on reactive power compensation // Teshabaev B. M., Youssoupaliev M. M., Saliev A. G., Siddikov I. H., Umarov F. U. / Appr. No.- 1864 ot 10.10.2008. Ministry of Justice of Rep. Uz. Tashkent, SI Uzdavenergonazorat.- 2008.- 24 p.
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