comet powerpoint template - university of texas at austin · by nicola gariboldi “high voltage...

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

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”

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

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

L E A R N M O R E

Oil Circuit Breaker designed in 1901

by JOSEPH N. KELMAN

40 kV – 300A

5C O M E T 2 0 1 7

CLOSE position Ideal conductor

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

OPEN position Ideal insulator

Grid 1 Grid 2

Operation Making and Breaking capability

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

7C O M E T 2 0 1 7

Disconnector ?

Visible Galvanic Separation

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

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

Usc ULoadUg

Loadsc

scLoad Z10..20Z

Ug 5%..10%IZU scsc

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

sc I10..20Z

UgIZU scscsc

Loadsc

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

2𝐿𝐼2

- Transient effect

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

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

rms etIi(t) 00 sinsin2 0cos2 tUu(t) rms

-0.04 -0.02 0 0.02 0.04 0.06 0.08time [s]

I_symm

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

rms etIi(t) 00 sinsin2 0cos2 tUu(t) rms

𝑰𝒑𝒆𝒂𝒌 = 𝟐. 𝟓 − 𝟐. 𝟕 𝑰𝒓𝒎𝒔

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

120°Ur [p.u.] Ir [kA] Is [kA] It [kA]

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 )

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

Joule dttiRdttiRE0

2 )()(

2)( tiRPJoule

specific let-through energy (or I2T)

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

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

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

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

OperatingMechanism

Circuit breaker

Interrupter

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

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

- Air Blast

- Vacuum

1910 1995

1955 1985

1950 1980

Minimum Oil

Bulk Oil

Vacuum

Single Pressure SF6

Air Blast

Dual Pressure SF6

1955 1980

20 30 40 50 60 70 80 90 00

22C O M E T 2 0 1 7

C O N C L U S I O N 2Bulk Oil circuit breakers

• Developed ~1910

• Technology, discontinued ~ 1995

• Still in service

23C O M E T 2 0 1 7

C O N C L U S I O N 2Minimum Oil circuit breakers

- Developed ~1955

- Technology, discontinued ~1985

- Still in service

24C O M E T 2 0 1 7

A i r b l a s t

Air blast circuit breakers

- Developed ~1950

- Technology, discontinued ~1980

- Still in service

25C O M E T 2 0 1 7

V a c u u m

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

26C O M E T 2 0 1 7

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

27C O M E T 2 0 1 7

Live Tank

- Insulating tank

- At Grid potential

- Support insulator

- Typical Europe

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

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

CLOSE position

OPEN position

Opening speedClosing speed

Travel curve

29C O M E T 2 0 1 7

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

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

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

F a u l t c l e a r i n g b a s i c s

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

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

Trip signal

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

Trip signal Contact Separation

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

Trip signal Contact Separation

Current Zero

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

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

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

39C O M E T 2 0 1 7

N o L o a d O p e n i n g1 - Close

2 – Contact separation

5 – Open

C o n t a c t s

Travel curve

Coil current

Opening

40C O M E T 2 0 1 7

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

3 – High Current

Current Zero

Opening

timeArcing

Clearing time

C o n t a c t s

Travel curve

Coil current

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

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

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

44C O M E T 2 0 1 7

Medium arcing time

Maximum arcing time

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

1911010

minmax

tmed 5.142

maxmin

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

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

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

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

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

comet powerpoint template - university of texas at austin · by nicola gariboldi “high voltage...

Documents

comet lulin

myanma awba group · 16-16, comet g21, comet npk 15-15-15,...

1.3-mb - comet information and the international comet

welcome to pro-lok website, the solid solutionbags o comet...

asynchronous ajax (aka comet) using the grizzly comet

comet-silver / comet prec 20-20 silver · comet 3-6 silver...

flute studies: gariboldi, op - raimundo pineda · pdf...

comet information and the international comet quarterly...

comet ison

comet database database system for comet devices · comet...

comet book

verani/gariboldi-riva-verani-2011.pdf · $/ c #5.7 #5+7f1 &...

comet club

comet landing

1997 apparition of comet hale-bopp observing comet hale-bopp

comet graphics

giuseppe gariboldi grands exercices op 139

comet overview

welcome t o a comet 2017 · comet 2017 1 comet 2017 welcome...

comet haviland