feee ensuring enhanced education unun kv17,52436 bilkv95125170 upup kv57,279,9117,6 1 1.the simple...

FEEEEnsuring Enhanced Education

PC BIL

D . U2.S 1,2

Un kV 17,5 24 36

BIL kV 95 125 170

Up kV 57,2 79,9 117,6

1

1. The simple protection method

The maximum distance:

Table 1. BIL and Up

(Với: D = a + b)

a : The maximum separation between J and pole-mounted transformer, mb : Distance between J and surge arrester, mUt : Arrester residual voltage, kVC: Velocity of wave propagation, C = 300 m/s.BIL: Basic Insulation Level of Transformer (KV)

I. The previous protection methodsI. The previous protection methods


2

2. The improved protection method (J. R. Lucas Method)

DO : Point of lightning stroke S0 : Rate of rise at O, kV/µs I0 : Lightning stroke current , kAX :Distance in which a surge with an infinite slope will decay to slope SA at A, mSA : Rate of rise of surge voltage at A, kV/µs : Reflection coefficient at transformerEt : Peak surge voltage at transformer, kVSf : Shielding factor (0,3 ÷ 0,5) N : The number of direct stroke into line, times/100km/year h : Height of nearby objects, m b : Horizontal span between outermost conductors, m Ng: Number of stroke per km2 per yearLF: Lifetime of transformer, year FR: Failure rate of transformer, %Nf : Number of lightning surges arriving at A /year, with slope higher SA

T : Wave front time, sk : Corona damping constant, kV.km/s .



3

D

s0

1ln( )

N.t .xI , kA

0,02878

s ,naêmLFtFR

g f

0,628h bN N 1 S

10

A

0T

1S , kV / s

1 k.xI Z2

t P

A

0,8E U CD , m

2S

t pE 2U , kV

O : Point of lightning stroke S0 : Rate of rise at O, kV/µs I0 : Lightning stroke current , kAX :Distance in which a surge with an infinite slope will decay to slope SA at A, mSA : Rate of rise of surge voltage at A, kV/µs : Reflection coefficient at transformerEt : Peak surge voltage at transformer, kVSf : Shielding factor (0,3 ÷ 0,5) N : The number of direct stroke into line, times/100km/year h : Height of nearby objects, m b : Horizontal span between outermost conductors, m Ng: Number of stroke per km2 per yearLF: Lifetime of transformer, year FR: Failure rate of transformer, %Nf : Number of lightning surges arriving at A /year, with slope higher SA





g f

0,628h bN N 1 S

10

AS

4

ycf

FR (%)N

LF

AA

S2.T 0,02878 .Z 1 S .k.Xf

0

xN N. e .dx

t P

A

0,8E U CD , m

2S

t pE 2U , kV

DO : Point of lightning stroke S0 : Rate of rise at O, kV/µs I0 : Lightning stroke current , kAX :Distance in which a surge with an infinite slope will decay to slope SA at A, mSA : Rate of rise of surge voltage at A, kV/µs : Reflection coefficient at transformerEt : Peak surge voltage at transformer, kVSf : Shielding factor (0,3 ÷ 0,5) N : The number of direct stroke into line, times/100km/year h : Height of nearby objects, m b : Horizontal span between outermost conductors, m Ng: Number of stroke per km2 per yearLF: Lifetime of transformer, year FR: Failure rate of transformer, %Nf : Number of lightning surges arriving at A /year, with slope higher SA





5

The previous methods: Accounting for influence elements with some experiment

parameters Just considered to single transformer substation

The proposed method: Determining surge arrester‘s location for 3-line, 2-transfomer

substation based on:

IEEE Std C62.22.2009

Influence elements (can be calculated)

Mean Time Between Failure (MTBF ) of Transformer



6

1m

3m 3m 3m

Line

A BLine

CLine

3m

T12T

D12D Arrester

S.1. Eliminate 1 transformer and determine the line which the lightning wave transmitted into.

S.2. Define the following parameters: - J, the common point between transformer, surge arrester and the line identified in step 01.

- D1, distance from J to pole-mounted transformer

- D2, distance from arrester to ground

(3-line , 2 - transformer substation) The proposed protection method based on IEEE Std C62.22.2009

S.3. Eliminate all line connected to D1

S.4. Calculate SJ

cJ

mtt tt.

K3 3S S .

N 2 d N 2

, kA/s

A, B, C: Line A, B, C.T1,T2 : Transformer T1 and T2

D1: Separate distance between T1 and line, m.D2: Separate distance between T2 and line, m.Ntt: Number of identified lines

II. II. The proposed protection method

d2 =


7

Transformer

Arrester

B

2

1

S

md

D

d

dJS.5. Distance : stroke - substation

m1

d =N

(MTBF).100

, km

J Jsa a a o1 2 .

2S 2SV V L. V d + d L .

Z Z

S.6. Voltage of Arrester

B: insulation equipments.d1: distance between line and arrester , m.D2: distance between arrester and ground, m.S : slope wave, kA/s.MTBF: mean time between failure, yearFR: acceptable failure rate, %N : number of stroke into line, times /100 km/yearKc: corona damping constant , kV.km/s Va: Mức bảo vệ đầu sóng của chống sét van tại 0,5s, kV Z : line impedance, L : Inductance, H.

with:1

MTBFFR(%)

The proposed method based on IEEE Std C62.22.2009



8

1m

3m 3m 3m

Line

A BLine

CLine

3m

T12T

D12D Arrester

S.7. Determine D1 and D2: D1 = min (D1_T1_Line A ; D1_T1_Line B ; D1_T1_Line C) D2 = min (D2_T2_Line A ; D2_T2_Line B ; D2_T2_Line C)


The proposed protection method based on IEEE Std C62.22.2009


9

Shielding Factor

Distance from objects to line (DO = x), m

(S

f)

Object ‘s Height

H = 10m: Sf = 5,013.10 - 7.x3 – 6,051.10-5.x2 – 0,003655.x + 0,4813 H = 14m: Sf = – 6,047.10 - 12.x5 + 1,452.10 - 8.x4 – 3,332.10 - 6.x3 +0,3459.10 - 3.x2 – 0,0247.x + 0,9982

Nonlinear regression technique

Curve Fitting Matlab

Build 16 relationships Sf, H và DO

Sf = SfL + SfR

SfL: S.F at left sideSfR: S.F at right side



10

The number of stroke into line

g gf fL fR

0,6 0,628h b 28h bN N 1 S N 1 S S

10 10

The inductance line which connect to surge arrester

, times/100km/year

- The inductance at line (length 1 m)

7 123o

DL =2.10 .ln

r , H/m

- The inductance line which connect to surge arrester

7 123o1 2 1 2.

DL = d + d L = d + d .2.10 .ln

r , H

Which: 3123 12 23 13D D D D , m



11

Check MTBF of transformer

2

a a2 T Ta aJ J T2

2,92.D.V .Z D.V .Z 0,77.L.C.V 1,54.L.V .C5,84.L.D.Z 1,54.C.LS S 0,385.C.V V V 0

ZZ

J

g c f

1000.SMTBF

0,6N .K .(28h b).(1 S )


(1)

(3)

Nonlinear regression technique

Curve Fitting Matlab

Build 6 relationships Sf, H và DO

0,9998gMTBF =107,5.N 0,02619

1g MTBF 195,4.N 0,0254 M

TB

F (

year

)

Ng (times/km2.year)


12

1. Introduction of OPSOLA Program

OPSOLA (Optimal Placement Software Of Lightning Arrester )

III. OPSOLA ProgramIII. OPSOLA Program

Determine optimized arrester’s location

Check MTBF of transformer

Single phase, single transformer

substation

Three-phase, two-transformer

substation


13

2. Calculation Interface

Main Interface Configuration



14

3. Single line, single transformer Substation



15

4. Three-line, two-transformer Substation


feee ensuring enhanced education unun kv17,52436 bilkv95125170 upup kv57,279,9117,6 1 1.the simple...

Documents