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18
Uo = ( +UB + UC)-U2AB - U2BC - U2CA. (26)
The equation (26) gave accurate results in all cases during calculations, doesn't have limitations in the sphere of use like (16), (19) and has a simpler form than the equation from [1].
Based on (26), the equation to determine symmetrical component of current of zero sequence will be an equation:
I =1 h■if + f + f f - f - f
0 v AB BC CA) 1A 1B 1C •
For quick evaluation of U, U, U0 in [1], it is permissible to use approximate equations:
U = 3 <Uab +UBC + Uca), (27)
U2 = 0,62-{UH6-U„), (28)
Uo = 0,62 -Uhm4) , (29)
where Uu6 (Utt6), Um (U— the most and least applicable values from three interphase (phase) voltages.
Unlike precise equations, the determination of symmetrical currents according to (28) and (29) is not permissible because I2 and I0 can reach significant values and these equations are based on the allowances: U2<<Ui and U<<U, which are usually performed in the networks of electric supply.
The attempts to simplify the definition of symmetrical components with the help of graphic constructions [6], nomograms [2, 7], tables [2] have been made repeatedly.
Geometric constructions allow clearly determining the calculation equations but require significant time.
Nomograms, despite small accuracy defined by one-two signs, play quite important role in the analysis of asymmetrical processes, definition of maximal values of linear and phase voltages and currents, qualitative evaluation of non-balanced processes during the prediction of dynamics of multi-phase systems in the emergency regimes, calculations of short circuits.
Despite the simplicity and sufficient accuracy, the tables and nomograms are not convenient to use during the processing of a big amount of measurement data.
Due to the availability of means of computing technology during the processing of a big amount of information, which is related to the control of quality of electric energy, precise analytical methods of determination of symmetrical components are preferred. The calculation of symmetrical components of voltages should be done according to the equations (24), (26), which have advantages before the equations recommended by GOST 32144-2013: and are more universal; give an opportunity to determine complex values and are simpler in calculation. Proposed expressions can be used to calculate complex values of symmetrical components of currents.
References:
1. ГОСТ 32144-2013 Электрическая энергия. Совместимость технических средств электромагнитная. Нормы качества электрической энергии в системах электроснабжения общего назначения. 01.01.2014.
2. Шидловский А. К., Музыченко А. Д. Таблицы симметричных составляющих. - К.: Наукова думка, 1976. - 204 с.
3. Железко Ю. С., Артемьев А. В. Определение симметричных составляющих напряжений с помощью вольтметра. - Известия вузов. Энергетика, 1985, № 2. - С. 10-15.
4. РД.153-34.0-15.501-00//Методические указания по контролю и анализу качества электрической энергии в системах электроснабжения общего назначения. В 2-х ч. Ч. 1. -Ташкент: ГАК Узбекэнерго. - 2000.-59 с.
5. Цапенко Е. Ф., Юнис Камаль. К вопросу расчета симметричных составляющих фазных напряжений электрических сетей. -Известия вузов, 1992, № 2. - С. 31-33.
6. Рожавский С. М. Номограмма для расчета режима несимметрично нагруженной трехфазной линии с изолированной нейтралью. -Известия вузов. Энергетика, 1965, № 6. - С. 93-94.
7. Ковзан А. А. Оценка несимметрии в трехфазных системах с помощью номограмм. -Известия вузов. Энергетика, 1961, № 7. -С. 28-34.
DOI: http://dx.doi.org/10.20534/ESR-16-9.10-226-228
Xudoyberdiyev Tolibjon, doctor of technical sciences, professor of the Department.
Boltaboev Bohodir, Candidate of the technical sciences, assistant professor.
Muradov Rahimjon, senior scientific employee researcher, PhD in Technique.
Razzoqov Bohodir,
Researcher, assistant of faculty the Faculty of Agro-engineering, Agricultural Institute of Andijan, the Republic of Uzbekistan.
E-mail: [email protected]
Doing up the scattered seeds of wheat soil of the furrow collected at formation
Abstract: In article problems about fillers are studied by the soil received from irrigating groove, the scattered seeds of wheat on a furrow on the basis of it parametres furrow and its wings for filling up are defined.
Doing up the scattered seeds of wheat soil of the furrow collected at formation
Keywords: The open space, the special installation, the new technology, irrigated flute, stroke soils, hillers with wings, a surface, a return proportion.
For crops of seeds of wheat on the open space in Republic farms disk seeders of type C3 [1, 87-88] till now were used. However, in view of their small quantity, for these purposes the adapted seeders of type HPy-0,5 and KPX-4 are applied. In this case, after scattering of seeds and cutting of irrigating furrows, along the edges of furrows the layer of earth that leads to decrease in a useful area of crops [2, 39-42] gathers. This process is shown on figure 1.
Considering it, there was a necessity of creation of a seeder of type C3, inexpensive and simple on a design, and such answering to necessary technology requirements of crops of seeds of wheat on the open space.
At the Andizhan agricultural institute one of variants of such seeder which has passed preliminary tests is created. The principle of work of the given seeder differs from a principle of work of seeder C 3 that seeds are not sowed and scattered, then the special devices are fallen asleep by a layer of earth collected at cutting irrigating furrow.
Figure 1. Formation of a soil layer at cutting of irrigating furrows.
The design of the given device consists oftwo parts (fig. 2): the first part (1) — serves for cutting irrigating furrow; the second part (2) — wings of a special configuration.
c = l .h = ^.h
cosa
(2)
Where h1 — thickness a layer of earth on a surface of grains.
At increasing an installation corner a the length covered increases and on the contrary.
At a =0 length covered will be the least and resistance of a layer of earth of the greatest. At a =90 ° length covered will be maximum and on a surface of grains soil is not leveled.
Definition of parameters of a layer of earth. The soil volume
should be such that it was spread a uniform layer defined height.
The bias of this layer trapezium shape should correspond to a bias
of an irrigating furrow. Ifwe consider, that the soil is leveled without
a bias the cross-section area of layer S2 will be defined as follows:
( + 2d1) -1 h (3)
S =-
Figure 2. The scheme spreading soils on a surface of a furrow and definition of its parameters
At cutting irrigating furrow on their edges the layer of earth which then by means ofwings is in regular intervals leveled over the scattered seeds gathers. In drawing one part of this wing is shown. For prevention of increase in a layer of earth and accordingly increases in forces of resistance, wings furrow are established under a corner a to a horizontal plane.
Definition of the area of a cross-section thickness of a layer of earth spreading on a furrow with the scattered seeds. Width of a furrow we will designate through l=b1+!1 On a furrow surface on which seeds are in regular intervals scattered, by means of wings furrow it is necessary to spread a uniform layer of earth. The size of a wing we will designate through L = e\ + Ij, where:
Where bj — length of the bottom basis of a trapeze, at a bias equal a, sm;
h2 - Height of a layer of earth, sm;
2d 1 - length of the bottom basis, at a bias equal a, sm.
The length of the bottom basis will be:
2d1 = e1i -2c ; c = h2-ctg$ (4)
Or, 2d1 = e; -2h2 ctgfi (5)
In that case S will be:
(6)
=-
11 =
l
L =
8 +1
(1)
cos a cos a cos a
Where b1 — Width of the basis of a layer of earth, sm; l1 — The distance between a layer of earth and the wing end, sm. If to express volume of a layer of earth leveled on a surface of grains through cross-section area S3 we will receive:
If to designate through to factor of expansion ofvolume of soil we will receive:
S2 = k ■ h2 ( - h2ctg$) (7)
Where k=1,20...1,25 — factor of expansion of volume of the loosened soil [3].
The zone A in the middle of a furrow should become covered by a part of soil collected by working body. This process is carried out by wings of a corresponding configuration. This area we will designate through S4, where:
S4 = l3 ■ h ; l3 = 05A (8)
4 3 3 3 cosa V^V
Then S2 it is possible to divide on two components:
S2 = S3 + s4 (9)
Substituting values and sampling, we will receive:
Kh\ ctgfy - Ke\h2 + h3 (( + ej ) + l3h3 = 0 (10)
If a = Kctge = kb\; c = h3 (( + ej ) + l3h3 ,
we will receive: Where
ahh -eh + c = 0
(11)
"al
(12)
k ■ b11 ±J(kb! )2 - 4xctg$ h3 (( + b1 ) + h3i
h2 =-^-
iKCtgfy
The sizes irrigating furrow it is defined from equality of trapezes ABCO and OAEF (fig. 3). Designating the area of trapeze ABCO through S1 and the area of trapeze OAEE through S2, we find depth of an irrigating furrow h
S1 = S2 (13)
f + B
(14)
2a 1 + e, , 2d1 + el,
, = 2 (2d' -1) = .
2a1 + e, 2a1 + e.
(15
The general depth of a furrow after leveling by a layer of earth: h=h1+h3 (16) Where h — the general cross-section depth of a furrow, sm.
Figure 3. The scheme to definition of depth of an irrigating furrow
Considering that depth of a furrow should be uniform and accepting an inclination corners a (fig. 3), we will define its sizes:
e = 8j • cosa and 2a = 2a1 • cosa (17)
Being based on the sizes e1=12 sm, 2 a=4 sm, 2d=6 sm and a= =60 ° and accepting width of a furrow equal B=90 sm, A=20 sm we define the sizes for h3=1 sm, 2 sm, 3 sm, 4 sm, 5 sm and 6 sm.
Results are shown on figure 4, whence it is possible to establish depth of an irrigating furrow depending on height of a layer of earth on a surface of seeds of wheat.
Definition distance between the ends of wings. The distance between the ends of wings is defined as follows:
B1 = e ■ 2b1 + 2ell and B1 = e + 2L (18)
h1 - depth of a furrow, h2 - height a layer of earth, h3 - height of a layer of earth on a surface of seeds.
Figure 4. Dependence of height of a layer of earth and depth of a furrow on height spreading a layer of earth on wheat seeds
Definition of a corner of an inclination of wings a. The corner of an inclination ofwings is defined considering resistance of a layer of earth and also this layer should not be excessive (i. e. ahead of wings the excessive layer should not gather).
References:
1. Efimenko T. A., Milovanov E. D. «Keng ihtisosli yosh mehanizatorlar uchun qo'llanma». - Toshkent. O'qituvchi. - 1978.
2. Muhamedov J. M., Bayboboev N. G. «G'o'za qator oradariga bug'doy ekish tehnologiyasi va tehnik vositalarini yaratishning ilmiy-amaliy asoslari». Toshkent. Fan va tehnologiya. - 2015.
3. Quziev U. T. Kombinatsiyalashgan agregat pushta hosil qilgichining parametrlarini asoslash: dis. kan. teh. nauk. - Toshkent, - 2010.
DOI: http://dx.doi.org/10.20534/ESR-16-9.10-228-230
Choriev Jamshid Muzaffarovich, Bakiev Masharif Ruzmetovich, Tashkent Institute of Irrigation and Melioration, Tashkent, Uzbekistan E-mail: [email protected]
Mobile water measuring weir with rectangular opening for farmlands
Abstract: The article shows the importance of equipping seasonal irrigation canals with water measuring devices and describes a mobile water measuring weir with a rectangular opening. It also provides some simple formulas for main sizes for weir elements and instructions for its installation.
Keywords: accurate water measurement, seasonal irrigation canals, mobile water measuring weir, rectangular opening, rubberized material.
