Qhov hluav taws xob poob ntawm lub zog xa hluav taws xob tuaj yeem suav tau raug suav nrog cov kauj ruam - los ntawm - cov qauv ntawm cov kauj ruam, cov tub ntxhais uas yog ΔU=I × R. Qhov hluav taws xob poob feem ntau yuav tsum tswj tsis pub dhau 5% ntawm qhov system voltage (piv txwv li, tsis pub ntau tshaj 19V rau 380V system).
Qhov Tseem Ceeb Ua rau Voltage Drop Cables inherently muaj kuj thiab reactance. Thaum tam sim no ntws los ntawm lawv, lub zog poob tshwm sim, manifesting raws li ib tug voltage poob. Cov xwm txheej cuam tshuam muaj xws li:
Cov khoom siv cable: tooj liab cable resistivity (0.0174 Ω·mm² / m) yog qis dua aluminium cable (0.0283 Ω·mm² / m), ua rau lub zog me me;
Cable ntev: Qhov ntev ntawm lub cable, qhov ntau dua qhov voltage poob;
Hla-sectional cheeb tsam: Qhov me me ntawm tus ntoo khaub lig-section, qhov ntau dua qhov tsis kam, thiab qhov tseem ceeb dua qhov voltage poob;
Load tam sim no: Lub zog siab dua, qhov siab dua tam sim no, thiab qhov tseem ceeb ntawm qhov poob qis;
Fais fab mov: inductive loads (xws li motors) muaj ib tug tsawg zog yam, uas exacerbates lub voltage poob.
Ob - los yog Peb-Txoj kev rau kev xam Cable Voltage poob
Kauj Ruam 1: Xam cov kab tam sim no
I
Kuv Muaj feem xyuam rau peb -theem AC systems:
I
=
P
3
×
U
×
cos
θ
I=
3
× U × cos θ
P
P
P: Load zog (kW)
U
U: Kab voltage (kV), feem ntau 380V, piv txwv li, 0.38kV
cos
θ
cosθ: Lub zog ua haujlwm, feem ntau yog 0.8-0.85
Piv txwv li: 55kW lub cev muaj zog,
I
=
55
/
(
1.732
×
0.38
×
0.8
)
≈
104.5
A I=55/(1.732×0.38×0.8)≈104.5A
Kauj Ruam 2: xam Cable Resistance
R
R
=
ρ
×
L
S
R=ρ× S L
ρ
ρ: Conductor resistivity (0.0174 rau tooj liab, 0.0283 rau txhuas)
L
L: Cable ntev (meter)
S
S: Tus neeg xyuas pib hla -sectional cheeb tsam (mm²)
Piv txwv li: 100-meter ntev, 16mm² tooj liab cable,
R
=
0.0174
×
100
/
16
≈
0.109
Ω R=0.0174×100/16≈0.109Ω
Kauj ruam 3: xam qhov voltage poob
Δ
U
ΔU Cov qauv siv yooj yim tshaj plaws (tsis quav ntsej reactance):
Δ
U
=
I
×
R
×
K
ΔU=I×R×K
K
K: Rau peb -phase systems, siv
3
≈ 1.732
3
≈1.732, ib zaug -theem yog 1 lossis 2 (tus naj npawb ntawm circuits)
Txuas ntxiv los ntawm qhov piv txwv yav dhau los:
Δ
U
=
104.5
×
0.109
×
1.732
≈
19.7
V
ΔU=104.5 × 0.109 × 1.732≈19.7V, suav txog 5.2% ntawm 380V, me ntsis tshaj qhov kev tso cai, tus ntoo khaub lig- ntu yuav tsum tau nce ntxiv.
