COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage...
Transcript of COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage...
![Page 1: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/1.jpg)
1C O M E T 2 0 1 7
C O M E T 2 0 1 7W E L C O M E T O A
T E C H N I C A L P A P E R P R E S E N T A T I O N
![Page 2: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/2.jpg)
2C O M E T 2 0 1 7
B y N i c o l a G a r i b o l d i
“High Voltage Circuit Breakers”
![Page 3: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/3.jpg)
3C O M E T 2 0 1 7
A B O U T T H E A U T H O RA B O U T T H E A U T H O R
• Master Electrical engineer - Politecnico of Milan
• Since July 2017 in Qualitrol as Technical Application Specialist
• 23 years in ABB
o 3 years Surge Arrester development
o 12 years High Voltage Circuit breaker development
o 5 years in GIS and Circuit breaker testing
o 3 years in Short Circuit Laboratory
• Member of CIGRE, IEC, IEEE
B R I E F B I O
N I C O L A G A R I B O L D IT e c h n i c a l A p p l i c a t i o n S p e c i a l i s t
![Page 4: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/4.jpg)
4C O M E T 2 0 1 7
A B S T R A C TS U M M A R Y
O V E R V I E W &
What is a Circuit Breaker?
Why do we need it?
Technology
Fault clearing basics
Wear
L E A R N M O R E
Oil Circuit Breaker designed in 1901
by JOSEPH N. KELMAN
40 kV – 300A
![Page 5: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/5.jpg)
5C O M E T 2 0 1 7
CLOSE position Ideal conductor
I
W h a t i s a C i r c u i t B r e a k e r ?
Electrical device connecting two grids
• Carrying Nominal & Fault current
• Isolating the grids & wistanding the
voltage
• Switching On & Off Nominal and
Fault current
Grid 1 Grid 2
Grid 1 Grid 2
OPEN position Ideal insulator
Grid 1 Grid 2
Operation Making and Breaking capability
![Page 6: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/6.jpg)
6C O M E T 2 0 1 7
Disconnector ?
Safety
• Guarantee the grid isolation
• Higher insulation between contact
than to ground
• BEFORE and AFTER the circuit
breaker
• Visible Galvanic Separation
disconnector Circuit breaker disconnector
Grid 2Grid 1
• Disconnector• Circuit breaker• Disconnector
![Page 7: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/7.jpg)
7C O M E T 2 0 1 7
Disconnector ?
Visible Galvanic Separation
![Page 8: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/8.jpg)
8C O M E T 2 0 1 7
Disconnector ?
Withstanding Voltage
- Visible gap
Carrying current
- Nominal & Fault
NO Clearing capability
- also very small
we need a Circuit Breaker
Substation 500 kV Eldorado Boulder City, Nevada.Disconnector trying to clear reactive current of ~ 100A
![Page 9: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/9.jpg)
9C O M E T 2 0 1 7
L o a d a n d F a u l t c u r r e n t
Nominal current
- l imited mainly by LOAD impedence
- Power factor ~ 1
Voltage drop ~ 5-10%
- short circuit impedance
ZscG
I
ZLoad
Usc ULoadUg
Loadsc
g
nZZ
UII
scLoad Z10..20Z
Ug 5%..10%IZU scsc
![Page 10: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/10.jpg)
10C O M E T 2 0 1 7
L o a d a n d F a u l t c u r r e n t
FAULT condition
- Load is short circuited
Current limited by grid impedance
- ~ 10 .. 20 In
Short circuit condition
scLoad Z10..20Z
n
sc
g
sc I10..20Z
UII
UgIZU scscsc
Loadsc
g
ZZ
UI
ZscGI
ZLoad
UscUg
![Page 11: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/11.jpg)
11C O M E T 2 0 1 7
F a u l t c u r r e n t
Grid impedence highly inductive
- R is low to l imit the l ine losses
- L is geometry dependent
Phase shift Voltage - Current
- ~ 90°
- Current Zero Voltage Max
Stored magnetic energy
-1
2𝐿𝐼2
- Transient effect
U
U
II
U
~90°
U
I
L
R
Z
t @50Hz @60Hz
[ms] [°el] [°el]
45 86.0 86.6
60 87.0 87.5
75 87.6 88.0
120 88.5 88.7
133 88.6 88.9f
R
L
R
L
t
t
2
tan
![Page 12: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/12.jpg)
12C O M E T 2 0 1 7
Fau l t I n i t i a t i onAt Current ZERO ~ at voltage PEAK
- Current is already at steady state value
- NO current transient
Y O U R A B S T R A C T M E S S A G E
tt
rms etIi(t) 00 sinsin2 0cos2 tUu(t) rms
90~0
-3
-2
-1
0
1
2
3
-0.04 -0.02 0 0.02 0.04 0.06 0.08time [s]
U
I_dc
I_symm
I
0
![Page 13: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/13.jpg)
13C O M E T 2 0 1 7
Fau l t I n i t i a t i on
~ at voltage ZERO
- Current should “jump” to max value (90deg)
- Transient DC component superimposed
- Condition for MAX peak for every L/R
Y O U R A B S T R A C T M E S S A G E
tt
rms etIi(t) 00 sinsin2 0cos2 tUu(t) rms
00
𝑰𝒑𝒆𝒂𝒌 = 𝟐. 𝟓 − 𝟐. 𝟕 𝑰𝒓𝒎𝒔
![Page 14: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/14.jpg)
14C O M E T 2 0 1 7
Three phase
- Voltage & Current are shifted 120 °el
- Fault initiation is a stochastic event
- Asymmetrical current will happen in one or the other phase
Y O U R A B S T R A C T M E S S A G E
120°Ur [p.u.] Ir [kA] Is [kA] It [kA]
![Page 15: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/15.jpg)
15C O M E T 2 0 1 7
S h o r t c i r c u i t c u r r e n tE l e c t r o - d y n a m i c s t r e s s
Proportional to
- square values of current
- instant value
Max peak = 2.5 – 2.74 I rms
- 𝜏 =𝐿
𝑅...45 – 133 ms
- Frequency
Fault current ~20 times nominal current
Mechanical stress ~ 1000 times higher
𝑭 = 𝑩𝟏 × 𝑰𝟐𝒍 =𝝁𝟎𝑰𝟏𝟐𝝅𝒅
𝑰𝟐
(𝐼1 = 𝐼2 )
𝑭 = 𝒌𝑰𝟐
Current peak 𝑰𝒑𝒆𝒂𝒌 (f, t)=
•2.5 Irms (50Hz, t = 45 ms)
•2.6 Irms (60Hz, t = 45 ms)
•2.7 Irms (t > 45 ms, frequency independent)
•2.74 Irms (Generator breakers IEEE C37.123, t = 133 ms )
Ipeak
![Page 16: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/16.jpg)
16C O M E T 2 0 1 7
S h o r t c i r c u i t c u r r e n tT h e r m a l s t r e s s
Joule effect
- R: resistance of the current path
- Max temperature proportional to
injected energy
Proportional to
- Effective current value
- Current duration 1 or 3 sec.
Fault current ~20 times nominal current
Thermal stress ~ 400 times higher
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1sec
Short circui current 1 sec
Current duration
TT
Joule dttiRdttiRE0
2
0
2 )()(
2)( tiRPJoule
specific let-through energy (or I2T)
![Page 17: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/17.jpg)
17C O M E T 2 0 1 7
C o n s e q u e n c e s o f D y n a m i c & T h e r m a l s t r e s s
F a u l t C u r r e n t
A company is an association or
collection of individuals, whether
natural persons, legal persons.
C O N C L U S I O N 1
C O N C L U S I O N 2
E l e c t r o - d y n a m i c T h e r m a l B o t h
![Page 18: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/18.jpg)
18C O M E T 2 0 1 7
C i r c u i t B r e a k e r
Interrupter
- Contacts to close and open
- Quenching / insulating medium
Operating mechanism
- Operates the contact with defined speed
Insulators / bushings
- Insulate from ground
- Between terminals
OperatingMechanism
U
![Page 19: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/19.jpg)
19C O M E T 2 0 1 7
C i r c u i t B r e a k e r
Three phase system
- 3 phases
- 3 Poles
- 1 or 3 operating mechanism
U3U2
U1
OperatingMechanism
U
OperatingMechanism
U
OperatingMechanism
U
Pole
Circuit breaker
Interrupter
![Page 20: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/20.jpg)
20C O M E T 2 0 1 7
P o l e
For very high voltage ( > 300kV)
very often Two or more interrupts in
series
To improve the voltage distribution
Grading Capacitors can be used
- 500 – 2000 pF to every chamber
- NOT always used
OperatingMechanism
U ~ 50% U~ 50% U
![Page 21: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/21.jpg)
21C O M E T 2 0 1 7
C i r c u i t B r e a k e r t e c h n o l o g y
Quenching medium
- Oil
- Air Blast
- Vacuum
- SF6
1910 1995
1955 1985
1950 1980
1965
Minimum Oil
Bulk Oil
Vacuum
Single Pressure SF6
1965
Air Blast
Dual Pressure SF6
1955 1980
20 30 40 50 60 70 80 90 00
![Page 22: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/22.jpg)
22C O M E T 2 0 1 7
O i l
A company is an association or
collection of individuals, whether
natural persons, legal persons.
C O N C L U S I O N 1
C O N C L U S I O N 2Bulk Oil circuit breakers
• Developed ~1910
• Technology, discontinued ~ 1995
• Still in service
C i r c u i t B r e a k e r t e c h n o l o g y
![Page 23: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/23.jpg)
23C O M E T 2 0 1 7
O i l
A company is an association or
collection of individuals, whether
natural persons, legal persons.
C O N C L U S I O N 1
C O N C L U S I O N 2Minimum Oil circuit breakers
- Developed ~1955
- Technology, discontinued ~1985
- Still in service
C i r c u i t B r e a k e r t e c h n o l o g y
![Page 24: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/24.jpg)
24C O M E T 2 0 1 7
A i r b l a s t
A company is an association or
collection of individuals, whether
natural persons, legal persons.
C O N C L U S I O N 1
C O N C L U S I O N 2
Air blast circuit breakers
- Developed ~1950
- Technology, discontinued ~1980
- Still in service
C i r c u i t B r e a k e r t e c h n o l o g y
![Page 25: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/25.jpg)
25C O M E T 2 0 1 7
V a c u u m
A company is an association or
collection of individuals, whether
natural persons, legal persons.
C O N C L U S I O N 1
C O N C L U S I O N 2Vacuum circuit breakers
- Developed ~1965
- Very common in medium voltage
- Available up to 145 kV
C i r c u i t B r e a k e r t e c h n o l o g y
![Page 26: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/26.jpg)
26C O M E T 2 0 1 7
S F 6
A company is an association or
collection of individuals, whether
natural persons, legal persons.
C O N C L U S I O N 1
C O N C L U S I O N 2Sulfur hexafluoride (SF6) circuit breakers
- Developed ~1965
- Predominant technology for High Voltage
- Alternatives are now available
• Dielectric strength 3 times than air
• Density ~ 6 times than air
• Condensation temperature @ 6 bar: –31.8 °C
• High affinity for electrons
C i r c u i t B r e a k e r t e c h n o l o g y
![Page 27: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/27.jpg)
27C O M E T 2 0 1 7
C i r c u i t B r e a k e r t e c h n o l o g y
Live Tank
- Insulating tank
- At Grid potential
- Support insulator
- Typical Europe
U
SupportInsulator
Dead Tank
- ALU Tank at GROUND potential
- 2 Bushings per pole are needed
- Lower center of gravity (earthquake)
- Typical USA
Bushings
T a n k
![Page 28: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/28.jpg)
28C O M E T 2 0 1 7
Operating Mechanism
- It moves the contacts of the interrupter
with the needed velocity
- Typical operating time 15 - 40 ms
- Typical operating velocity 3 - 12 m/s
- Typical stored energy 300 - 8000 J
Interrupter
- It clears & makes the current
- Contact distance to withstand the voltage
- Typical contact stroke 80 - 200 mm
OperatingMechanism
Interrupter
stro
ke
time
CLOSE position
OPEN position
Opening speedClosing speed
Travel curve
C i r c u i t B r e a k e r t e c h n o l o g y
![Page 29: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/29.jpg)
29C O M E T 2 0 1 7
C i r c u i t B r e a k e r t e c h n o l o g y
Gang operated Circuit Breaker
1 operating mechanism for 3 poles
Single Pole operated Circuit Breaker
1 operating mechanism per every pole
Linkage
Op. Mech
O p e r a t i n g M e c h a n i s m
![Page 30: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/30.jpg)
30C O M E T 2 0 1 7
O p e r a t i n g M e c h a n i s m
Spring
- ~ 51% breakers in service. Trend increasing
Hydraulic
- ~ 26% breakers in service. Trend decreasing
Pneumatic
- ~ 22% breakers in service.
- Oldest technology almost discontinued
Motor drive or magnetic actuator
- < 1% breakers in service.
CIGRE survey 2004 -2007
CIGRE survey 1988 -1991
![Page 31: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/31.jpg)
31C O M E T 2 0 1 7
Norma l cond i t i on
- Circuit breaker close
- Load current
- U load = Ugrid ~ Us
Y O U R A B S T R A C T M E S S A G EUloadUgridUs
I
F a u l t c l e a r i n g b a s i c s
![Page 32: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/32.jpg)
32C O M E T 2 0 1 7
Fau l t
- Short circuit current
- U load = Ugrid = 0 (short circuit)
- Us = I Zsc
Y O U R A B S T R A C T M E S S A G EUloadUgridUs
I
F a u l t c l e a r i n g b a s i c s
![Page 33: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/33.jpg)
33C O M E T 2 0 1 7
Tr i p s i gna l
- Sent by protection system
- Minimum reaction time = half period
- 8.3 ms @ 60Hz, 10 ms @ 50Hz
- Circuit breaker starts opening
UloadUgridUs
I
F a u l t c l e a r i n g b a s i c s
Trip signal
![Page 34: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/34.jpg)
34C O M E T 2 0 1 7
Con tac t
Sepa ra t i on
- Arc burns between contacts
- Current flows through the contact gap
- Arc voltage << System voltage
- U load = Ugrid ~ 0 (arc voltage)
UloadUgridUs
I
F a u l t c l e a r i n g b a s i c s
Trip signal Contact Separation
![Page 35: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/35.jpg)
35C O M E T 2 0 1 7
Cur ren t C lea red
- At Current Zero
- Load side of the grid isolated
- Source side voltage can go back to System value
- Transient Recovery voltage charging stray capacitance
UloadUgridUs
I
F a u l t c l e a r i n g b a s i c s
Trip signal Contact Separation
Current Zero
![Page 36: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/36.jpg)
36C O M E T 2 0 1 7
G A S c i r c u i t b r e a k e r g e o m e t r y
Movement
CLOSE OPEN
Contact Gap
![Page 37: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/37.jpg)
37C O M E T 2 0 1 7
Stationary arcing contact (Copper –Tungsten)
Main nozzle (PTFE) Aux nozzle (PTFE)
Moving arcing contact (Copper –Tungsten)
Heating Channel
Exhaust tube (steel)
Moving main contact (silver plated Copper)
refilling valve
Heating volume
Puffer volume
Intermediate valve
Stationary main contact (silver plated Copper)
SF6 @ 6 bar
G A S c i r c u i t b r e a k e r g e o m e t r y
![Page 38: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/38.jpg)
38C O M E T 2 0 1 7G A S c i r c u i t b r e a k e r g e o m e t r y
Stationary main contact (silver plated Copper)
Stationary arcing contact (Copper –Tungsten)
Main nozzle (PTFE) Aux nozzle (PTFE)
Moving arcing contact (Copper –Tungsten)
Heating Channel
Exhaust tube (steel)
Moving main contact (silver plated Copper)
Puffer volume Heating volume
SF6 @ 6 bar
![Page 39: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/39.jpg)
39C O M E T 2 0 1 7
time
N o L o a d O p e n i n g1 - Close
2 – Contact separation
5 – Open
1
5
2
C o n t a c t s
Travel curve
Coil current
Opening
time
3
4
3
4
![Page 40: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/40.jpg)
40C O M E T 2 0 1 7
time
O p e n i n g w i t h c u r r e n t
1 - Close
2 – Contact separation
5 – Open
1
3
2
3 – High Current
Current Zero
4
5
Opening
timeArcing
time
Clearing time
C o n t a c t s
Travel curve
Coil current
![Page 41: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/41.jpg)
41C O M E T 2 0 1 7
IC u r r e n t C l e a r i n g
S u m m a r y
• ARC between arcing contacts insulating medium turns into plasma
• The Arc Voltage is TOO low to influence the current.
• The breaker is mechanically OPEN, but electrically CLOSE
I t c a n o n l y h a p p e n a t c u r r e n t Z e r o
• The interrupter is designed the BLOW “fresh” gas in the arc region
• The Cooling Power is enough to turn Plasma back into dielectric medium
• The current STOPS flowing
T h e r m a l p h a s e @ C u r r e n t Z e r o
• The recovery voltage appears across the contacts with a transient
• The Transient Recovery Voltage causes Dielectric Stress
• Contact distance and gas density have to be enough to withstand it
D i e l e c t r i c P h a s e – j u s t A F T E R c u r r e n t Z e r o
• Plasma turned back into dielectric medium
• Contact Distance & Density high enough to withstand the Recovery Voltage
• .... If this is NOT the case the breaker has to wait the NEXT Current ZERO
I n t e r r u p t i o n i s s u c c e s s f u lthermal phase
dielectric phase
~ 100-1000 us
![Page 42: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/42.jpg)
42C O M E T 2 0 1 7
I n t e r r u p t i n g w i n d o w
- Shortest t ime between:o Contact Separat ion
o Cleared current zero .
Minimum arcing time
- If CS moves closer to Current Zero o Clear ing condi t ions are not fu l f i l led
o Pressure bu i ld up no t enough
o Contac t d is tance a t cu r ren t ze ro too sma l l
- The breaker wil l NOT clear and it has to
wait for the NEXT Current Zero
Maximum arcing time
- Any other clearing condition is within the
Min and Max arcing time
Tarc max
dt = 18°
Tarc min
Tarc max = Tarc min + 180° -dt
Contact Separation
![Page 43: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/43.jpg)
43C O M E T 2 0 1 7I n t e r r u p t i n g w i n d o w ( s i n g l e p h a s e s y s t e m )
Minimum arcing time
Maximum arcing time
Minimum arcing time
Maximum arcing time
![Page 44: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/44.jpg)
44C O M E T 2 0 1 7
Medium arcing time
Maximum arcing time
tarc
tarc
tarc
Minimum arcing time
S h o t s e q u e n c e s i n g l e p h a s e t e s t
mst 10min
mst
dT
Ttt
1911010
3602
max
minmax
mstt
tmed 5.142
maxmin
![Page 45: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/45.jpg)
45C O M E T 2 0 1 7
Current interruption = arc
two main wearing effects
• Nozzle ablation
• Contact erosion
W e a r
Nozzle ablation
Contact erosion
![Page 46: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/46.jpg)
46C O M E T 2 0 1 7
Arc energy sublimates PTFE material
The PTFE gas contributes to interruption
- Pressure build up
- High electron affinity
Ablation nozzle geometrical changes:
Higher distance from arc to PTFE surface
Less energy abortion Less PTFE vapours
Bigger cross section:
Lower pressure build up
Less thermal clearing capabil i ty
N o z z l e A b l a t i o n
![Page 47: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/47.jpg)
47C O M E T 2 0 1 7
TWO contact systems
Main for nominal current (~ 30uohm)
Arcing for interruption (~ 300uohm)
CommutationTime
-Current from Main to Arcing contacts
-Arc voltage between main contacts ~ 20 V
-~ 1.. 3 ms depending from:- Current Ampl i tude
- Resis tance of two contact systems
-Contact overlap is needed
Erosion earlier contact separation
If commutation is not over fatal failure
C o n t a c t E r o s i o n & C o m m u t a t i o n
Contact erosion = earlier contact separation
![Page 48: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/48.jpg)
48C O M E T 2 0 1 7
P A P E R Q & AC O M E T | C O L L A B O R A T E | S H A R E
K N O W L E D G E | P R O G R E S S
![Page 49: COMET PowerPoint Template - University of Texas at Austin · By Nicola Gariboldi “High Voltage Circuit Breakers ...](https://reader033.fdocuments.us/reader033/viewer/2022051601/5ad44e967f8b9a5d058bb7e8/html5/thumbnails/49.jpg)
49C O M E T 2 0 1 7
+ 4 1 7 9 5 9 3 0 8 5 3 n g a r i b o l d i @ q u a l i t r o l c o r p . c o m N i c o l a G a r i b o l d i
NICOLA GARIBOLDI
.
Qualitrol Technical Application Special ist
GET IN TOUCH