FEEE Ensuring Enhanced Education P C BIL D . U 2.S 1,2 U n kV 17,5 24 36 BIL kV 95 125 170 U p kV 57,2 79,9 117,6 1 1. The simple protection method The maximum distance: Table 1. BIL and U p (Với: D = a + b) a : The maximum separation between J and pole-mounted transformer, m b : Distance between J and surge arrester, m U t : Arrester residual voltage, kV C: Velocity of wave propagation, C = 300 m/s. BIL: Basic Insulation Level of I. The previous protection I. The previous protection methods methods
I. The previous protection methods. The maximum distance:. The simple protection method. (Với: D = a + b). Table 1. BIL and U p. a : The maximum separation between J and pole-mounted transformer, m b : Distance between J and surge arrester, m U t : Arrester residual voltage, kV - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
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
FEEEEnsuring Enhanced Education
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 .
I. The previous protection methodsI. The previous protection methods
FEEEEnsuring Enhanced Education
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
T : Wave front time, sk : Corona damping constant, kV.km/s .
2. The improved protection method (J. R. Lucas Method)
I. The previous protection methodsI. The previous protection methods
FEEEEnsuring Enhanced Education
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
T : Wave front time, sk : Corona damping constant, kV.km/s .
2. The improved protection method (J. R. Lucas Method)
I. The previous protection methodsI. The previous protection methods
FEEEEnsuring Enhanced Education
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
I. The previous protection methodsI. The previous protection methods
FEEEEnsuring Enhanced Education
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 =
FEEEEnsuring Enhanced Education
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
II. II. The proposed protection method
FEEEEnsuring Enhanced Education
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)
II. II. The proposed protection method
The proposed protection method based on IEEE Std C62.22.2009
FEEEEnsuring Enhanced Education
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
II. II. The proposed protection method
FEEEEnsuring Enhanced Education
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
II. II. The proposed protection method
FEEEEnsuring Enhanced Education
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 )
II. II. The proposed protection method
(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)
FEEEEnsuring Enhanced Education
12
1. Introduction of OPSOLA Program
OPSOLA (Optimal Placement Software Of Lightning Arrester )