d _MAX U d _MIN

Ñ_MAX U _MIN U

U

mA

COSH x V kVA RO x V kVA V V P V

R R R D mA

kV s

Èçêëþ÷âà ñå çàùèòàòà íà îòîïëèòåëíèÿ òðàíñôîðìàòîð.

ëàáîðàòîðèÿòà.

V

Êîãàòî îòïàäíå ìðåæîâîòî íàïðåæåíèå.

R R

R R

U V

U kV

I m

V P

U kV

I m

U_f V

R R kW W R kW W

d

r mm mm V e V

Çà öåëòà ïúðâî ñå èçìåðâà ñïåöèôè÷íîòî ñúïðîòèâëåíèå íà ïî÷âàòà êîåòî òðÿáâà äà áúäå =100 m

r

m

íà çàùèòíèòå çàçåìèòåëíè è ìúëíèåçàùèòíè óðåäáè ñå

V

V R

W W

V

R

R R

íå ïî-ìàëêà îò 500mm

³ m

³ m

W

M

R

R R R

- R

Ñîíäàòà R R R

R R

W

W W

W W

W W

W W

Ïðè ïðåâèøàâàíå íà R R m

R

è ñå âúðòè ðúêîõâàòêàòà, äîêàòî ñòðåëêàòà íà èíäèêàòîðà ìàêñèìàëíî ñå äîáëèæè äî ïîëîæåíèå “0”.

Àêî èçìåðâàíîòî ñúïðîòèâëåíèå ñå îêàæå íàä 10W

Çàçåìëåíèå: òåîðèÿ è ïðàêòèêà, https://www.ixbt.com/peripheral/ground.html, 2000.

Meeker D Finite Element Method Magnetics Version User s Manual

Meeker D FEMM 2 Electrostatics Tutorial

Güemes J. A., F. Rodriguez, J. M. Ruiz1, F. E. Hernando Determination of the ground resistance and distribution of potentials in grounding grids using FEM International conference on renewable energies and power quality (ICREPQ' Las Palmas de Gran Canaria, 20

ElecNet v.7, Live Docs, https://www.infolytica.com

Mauricio Valencia Ferreira, Luz Patrick Dular, ANALYTICAL AND FINITE ELEMENT MODELING OF GROUNDING SYSTEMS, IX International Symposium on Lightning Protection 26th-30th November 2007 – Foz do Iguaçu, Brazil.

Popovic Z B Popovic Introductory Electromagnetics Prentice Hall, 1999.

PROGRAM STREGNTH

DIMENSION QN1(60),BN1(60),QN2(60),BN2(60),ED(11)

UF=48.0

R=5.0

S=2.5

PI=3.1459

EPS=8.85E-12

QN1(1)=0*PI*EPS*R*UF

BN1(1)=0.0

QN2(1)=(-QN1(1)*R)/(S+2.0*R)

BN2(1)=(R**2)/(S+2.0*R)

DO 2 I=2,60

QN1(I)=-QN2(I-1)*R/(S+2.0*R-BN2(I-1))

BN1(I)=(R**2)/(S+2.0*R-BN2(I-1))

QN2(I)=-QN2(I)*R/(S+2.0*R-BN1(I))

BN2(I)=(R**2)/(S+2.0*R-BN1(I))

CONTINUE

WRITE(*,4) (QN1(I),BN1(I),QN2(I),BN2(I),I=1,60)

FORMAT(3X,7HQN1(I)=,E11.4,2X,7HBN1(I)=,F5.3,2X,

*7HQN2(I)=,E11.4,2X,7HBN2(I)=,F5.3)

DO 5 J=1,11

XR=(J-1)*S/10.0

SUM=0.0

DO 6 I=1,60

SUM=SUM+QN1(I)/(0*PI*EPS*((R-BN1(I)+XR)**2))

*-QN2(I)/(0*PI*EPS*((R-BN2(I)+S-XR)**2))

CONTINUE

ED(J)=SUM

CONTINUE

WRITE(*,7) (ED(J),J=1,11)

FORMAT(3X,6HED(J)=,F6.3)

DELTA=0.9

BETA=1.0

BETA=0

DO 8 J=1,11

BX=BETA*ED(J)

IF(BX/DELTA.LT.25) GO TO 10

BETA=BETA+0.2*DELTA*((BX/DELTA-25)**2)

CONTINUE

BETO=BETA*S/10.0

WRITE(*,9) BETA,BETO

FORMAT(3X,5HBETA=,F2,2X,5HBETO=,F6.3)

BETA=BETA+0.02

IF(BETA.LE.1.3) GO TO 12

DELTA=DELTA+0.1

IF(DELTA.LE.1.1) GO TO 13

STOP

END