«elektr stansiyalari,tarmoqlari va tizimlari»

Liniyaning boshlanishida quvvat va kuchlanish berilgan holat. Yuqorida

ko„rib o„tilgan holatdagi singari liniya toki
^I12
ni liniyaning bo„ylama qismi

boshlanishidagi quvvat



_S
(1)
12
va kuchlanish
U^₁ orqali ifodalasak, u holda ma‟lum

shakl almashtirishlardan so„ng liniyada kuchlanish pasayishining bo„ylama va ko„ndalang tashkil etuvchilari uchun liniya boshlanishidagi ma‟lumotlar bo„yicha ifodalarni hosil qilamiz:

 ₍₁₎  _P(1) _{r
 Q}(1) _x
; (3.30)

^U12
12 12 12 12
U₁

_{ (1)}  _P(1) _{x
 Q}(1) _r
. (3.31)

^U12
12 12 12 12
U₁

Liniya oxiridagi kuchlanish:
U^  U  U^{ ( 1 )}  jU^{ ( 1 )} . (3.32)
2 1 12 12

Yuqoridagilarga muvofiq liniya oxiridagi kuchlanish moduli va fazasi qo„yidagicha aniqlanadi:
U₂  ; (3.33)


^ U ^{(1) }
 ₂  arctg^{ 12 } . (3.34)

U

12 

 1
 _{ U} ⁽¹⁾ 

2. 
   ,b- rasmda tasvirlangan kuchlanishlar vektor diagrammasidan ko„rinadiki, kuchlanish pasayishining ko„ndalang tashkil etuvchisi U₁₂ kichiklashgan sari kuchlanish isrofi kuchlanish pasayishining bo„ylama tashkil etuvchisiga yaqinlashib boradi. Shu sababli 110 kV va undan past kuchlanishli tarmoqlarni hisoblashda ushbu tashkil etuvchi etarlicha kichik bo„lganligi sababli liniya oxiridagi ma‟lumotlar bo„yicha hisoblashlarda
   

  
₍₂₎  _P(2) _{r
 Q}(2) _x
, (3.35)

^U12
^U12
12 12 12 12
U ₂

liniya boshlanishidagi ma‟lumotlar bo„yicha hisoblashlarda esa

  

(1)  _P(1) _{r
 Q}(1) _x

^U12

qabul qilinadi.

^U12
12 12 12 12
U₁
(3.36)

2. Elektr tarmoqlarida kuchlanishni rostlash usullarini tadqiq qilish

Transformatorlarning transformatsiyalash koeffisientlarini o’zgartirib rostlash
Yuqorida ko‟rib o‟tilgan podstansiyalarda kuchlanishni rostlash usulining samaradorligi bilan sхemasi 3.3- rasmda keltirlgan elektr tarmog‟ida podstansiyaning pastki tomonida kuchlanishni rostlash misolida tanishamiz.

3.3-rasm

Kuchlanishni pasaytiruvchi podstansiyaning pastki tomonida U_{n hoh}=10.5 kV kuchlanishni transformatorning transformatsiyalash koeffiseintini tanlash hisobiga rostlash talab etiladi.
Transformator kuchlanishni yuklama ostida rostlovchi YuOR ±9x1,78 tipidagi qurilma bilan jihozlangan.
Elektr tarmoqni almashtirish sxemasi tuzamiz va uning parametrlarini topamiz.
Liniya o‟tkazgichining markasi AC-185.
Uning solishtirma parametrlari: r₀=0.17 Om/km, x₀=0.409 Om/km/, b₀=2.82 *10^-6 Sm/km. Liniyaning uzunligi: l=50 km.
Liniya almashtirish sхemasining parametrlarini topamiz: r_l=r₀ *l=0.17*50=8.5 Om

N l
x_l=x₀*l=0.409*50=20.45 Om b_l=b₀*l=2.82*10^-6*50=0.141*10^-3 Sm Q_s=U ²*b =110²*0.141=1.706 MVAr
Transformator markasi ТРДНЦ-40000/110
U_YuK=115 kV U_PK=10.5 kV U_k=10.5% i=0.5 ∆P_S.I=120 kVt ∆P_QT=265 kVt

_{R } _QT
*U ²
_ 265 *115²



N
 2.19 , Om
X  ^UK
%*U ²
_ 10.5 *115²

 34.72 Om

N

N

S

N
^T 2 ₄₀2
^T 100S
100 * 40

_ST
 
S.I
 0.12 , MVt
Q_ST
 I _{S .I} %* S_N
100
_ 0.5 * 40 _{ 0.2}
100
MVar,

bu yerdagi P_QT –qisqa tutashish isrofi, MVt
U_k % - qisqa tutashuv kuchlanishi, % U_N
P_S.I -salt ishlash isrofi, MVt I_S.I % - salt ishlash toki, % I_N
Elektr tarmoqning almashtirish sхemasini chizamiz (3.4-rasm)

3.4-rasm

Elektr tarmog‟ining holatini hisoblaymiz.

Р_T
Р²  Q²

U
_ T T _{ R}T

N
_ 35² 15²
110²
 2.19  0.262 _MVt

Q_T
Р²  Q²

U
_ T T _{ X}T

N
_ 35² 15²
110²
34.72  4.16

MVAr

∆S=0.262+j4.16 MVA
^{S1  SYu  ST  (35  j15)  (0,262  j4.16)  35.262  j19.16} MVA
S₂  S₁  S_pul  (35.262  j19.16)  (0.12  j0,2)  35.382  j19.36 _MVA
Liniyaning oxirida hosil bo‟lgan zaryad quvvatini hisobga olamiz:

S₃  S₂

• 
  Q_S
  

2

 (35.382 

j19.36)  j ^1.706  35.382 

2
j18.507
MVA

Liniyadagi quvvat isrofi:

Р²  Q²

U

2
Р_L  ^{3 3}  R_L 
N
35.382² 18.507²
110²
8.5  1.12

MVt

Q_L
Р²  Q²

U

2

L
_ 3 3 _{ X}
N
_ 35.382² 18.507²
110²
 20.45  2.69

MVAr

S₄  S₃  S_L  (35.382  j18.507)  (1.12  j2.69)  36.502  j21.197
MVA

Liniyaning boshida generatsiya qilinayotgan quvvatni hisobga olamiz:

S₅  S₄

• 
  Q_S
  

2
 (36.502  j21.197)  j ^1.706  36.502  j20.344
2

MVA

Kuchlanish yo‟qotilishini aniqlash Liniyadagi kuchlanish yo‟qolishi:

^U12
_ Р₄  R_L  Q₄  Х_L
U_N
 36.502  8.5  21.197  20.45 _{ 6.76 kV}
110

2- tugundagi keltirilgan kuchlanish:
^{U2  U1  U12  110  6.76  103.24} kV
Transformatordagi kuchlanish yo‟qolishi:

^U 23
_ Р₁ R_T  Q₁ Х_T
U _2
 35.262  2.19  19.16  34.72 _{ 7.2 kV}
103.24

Podstansiyaning PK tomonidagi kuchlanish:
^{U3  U2  U23 103.24  7.2  95.04} kV
Shohobcha kuchlanishi:

^Ushoh
_ U₃ U _PK
10.5
_ 95.04 10.5 _{ 95.04 kV}
10.5

Shohobchaning standart kuchlanishini tanlaymiz

U_st  96.55 kV
Podstansiyaning PK tomonidagi hohlangan kuchlanish:

^UN .hoh
_ U ₃
K_T
 ^95.64 10.5  10.5
96.55

kV.

Shunday qilib ushbu holatda podstansiyaning paski tomonida kuchlanishning talab etilgan qiymati 10,5 kV transformator transformatsiyalash koeffitsienti K_t=96,55/10,5 bo‟lganda ta‟minlanadi.

Tarmoqning reaktiv qarshiligini kompensasiyalab rostlash

Kuchlanishni elektr tarmoqning reaktiv qarshiligi kompensatsiyalab rostlash usulining samaradorligi bilan sхemasi 3.5- rasmda keltirilgan elektr tarmog‟ining oхirgi punktida 110 kV kuchlanishni ta‟minlash masalasida tanishib o‟tamiz.

3.5- rasm

Elektr tarmoqni almashtirish sxemasi tuzamiz va uning parametrlarini topamiz.
Liniya markasi AC-240 r₀=0.13 Om/km x₀=0.401 Om/km b₀=2.85 *10^-6 Sm/km l=40 km
R_L1=r₀ *l=0.13*40=5.2 Om X_L1=x₀*l=0.401*40=16.04 Om b_L1=b₀*l=2.85*10^-6*40=0.114*10^-3 Sm

Elektr tarmoqning almashtirish sхemasi 3.6- rasmda keltirilgan.

3.6- rasm.

Elektr tarmoqning holatini hisoblaymiz:

1. 
   
   N L1
   liniyaning zaryad quvvati: Q_s1=U ²*b =110²*0.114=1.38 MVAr
   
2. 
   
   N L2
   liniyaning zaryad quvvati: Q_s2=U ²*b =110²*0.0.0705=0.854 MVAr 2-Liniyaning oxirida hosil bo‟lgan zaryad quvvatini hisobga olamiz:
   

S₄  S₃

• 
  ^QS 2
  

2

 (15 

j7)  j ^0.854  15  2

j6.573
MVA

Liniyadagi quvvat isrofi:

Р²  Q²

U

2
Р_L2  ^{4 4}  R_L2 
N
15²  6.573²
110²

 4.25  0.094

MVt

Р²  Q²

U

2
Q_L2  ^{4 4}  X_L2 
N
15²  6.573²
110²
10.225  0.23

MVAr

S₅  S₄  S_L2  (15  j6.573)  (0.094  j0.23)  15.094  j6.803
MVA

Liniyaning boshida generatsiya qilinayotgan quvvatni hisobga olamiz:

S₆  S₅

• 
  ^QS 2
  

2
 (15.094  j6.803)  j ^0.854  15.094  j6.376
2

MVA

S₇  S₆  S₂  (15.094  j6.376)  (20  j8)  35.094  j14.376
MVA

1-Liniyaning oxirida hosil bo‟lgan zaryad quvvatini hisobga olamiz:

S₈  S₇

• 
  ^QS1