CONTROLLED SWITCHING CIRCUIT BREAKER CONSIDERATIONS · 2014. 1. 14. · ALSTOM T&D Seminar/Workshop...
Transcript of CONTROLLED SWITCHING CIRCUIT BREAKER CONSIDERATIONS · 2014. 1. 14. · ALSTOM T&D Seminar/Workshop...
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CIGRE WG A3.07
CONTROLLED SWITCHING
CIRCUIT BREAKER CONSIDERATIONS
Victor F. HermosilloALSTOM T&D
Seminar/Workshop on Controlled SwitchingCIGRE WG A3.07
IEEE/PES Switchgear Committee MeetingSt. Pete Beach, Florida
May 2003
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Circuit Breaker Considerations
� Circuit breaker characteristics� Interrupter wear� Life extension, maintenance intervals� Circuit breaker performance� Benefits for switched equipment� Benefits for the power system & equipment� Conclusions
OUTLINE
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Circuit Breaker Characteristics
Independent-Pole Operated
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Independent-Pole Operated
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Mechanically-Staggered Linkage
Circuit Breaker Characteristics
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Mechanically-Staggered Linkage
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Spring Mechanism
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Hydraulic Mechanism
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� Effect of idle time� Influence of ambient temperature on operating time� Hydraulic pressure - Spring constant
-1
0
1
2
3
0.1 1 10 100 1000
idle time (hrs)
clos
ing
time
varia
tion
(ms)
HydraulicMechanism
SpringMechanism
Timing Characteristics
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0 30 60 90 120 150 180 210 240 270 300 330 3600,0
0,2
0,4
0,6
0,8
1,0
T Target Target Pointnominal instant of contact touch
Volta
ge a
cros
s cir
cuit-b
rake
r (ab
solut
e va
lue) [
pu]
�t making
k + k0 �
k - k0 �
Controlled Closing - RDDS
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Live-Tank Circuit Breaker
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Field Simulation
15 mm and 4.0 msfrom contact touch
02040
6080
100120140
160180200
0.000 0.004 0.008 0.012 0.016
0
5
10
15
20
25
30
35
40
0 5 10 15 20 25 30 35 40
d (mm)
E (k
V/m
m)
Controlled Closing - RDDS
Emax
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Benefits for the Circuit Breaker
� Extension of circuit breaker life,
� Increase in time intervals between interruptermaintenance or retrofit,
� Added value associated with circuit breakerperformance enhancement during currentinterruption in the thermal or in the dielectricregion.
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Interrupter Wear
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Interrupter Wear
Benefits of controlled switching for the purposesof life extension, reduction of maintenance cost:
� Decrease in magnitude of energization currents.
� Reduce associated interrupter wear.
� Lower probability of occurrence of damagingrestrikes.
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Interrupter Wear
� Arcing contact wear
– Source is burning arc across the gap.
– Loss of material caused by vaporization, melting andburnoff.
– Consequences are contact shape distortion andincrease in surface roughness.
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Electrical Wear of an Interrupter
� Depends on:– contact material composition
and micro-structure– contact surface porosity– initial contact shape– manufacturing process– arc current duration,
amplitude, shape� Implications
– erosion, burnoff, vaporization– change in shape, surface
Arcing Contact Wear
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� Depends on:– nozzle geometry– material (teflon) and fillers
� Implications:– increase in diameter of throat– flake-off, erosion, vaporization of
inside surface– changes to the dynamic gas flow
during interruption– degradation of breaker
performance (thermal region)
Teflon Nozzle Ablation
Electrical Wear of an Interrupter
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Interrupter Wear
� Definition of maintenanceinterval
� Number of allowableoperations betweenmaintenance/refurbishment
� Simple relation between theinterrupted current and amaximum number ofoperations
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Improved Assessment of Interrupter Wear
� Separate limits forarcing contact wearand nozzle ablation
� Specific to interrupterdesign
� Can be implementedtogether withelectronic monitoring
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Maintenance Intervals and Costs
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Circuit Breaker Performance Enhancement
� Improve performance during interruption– Thermal region of interruption– Dielectric region of interruption
� Increase or decrease arcing time– Life extension– Unusual system voltages (25 Hz rail system)– Higher X/R ratios– Further reduce restrike probability for severe TRV
applications
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Thermal (Energy Balance) Region
• Rate of Rise of Recovery Voltage (RRRV)• Initial Transient Recovery Voltage (ITRV)• Reignition if current re-established <1/4 cycle
successful interruption failure (reignition)
ETRVETRV
Circuit Breaker Performance Enhancement
ifault
vTRV
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Circuit Breaker Performance Enhancement
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Dielectric Region
• Peak value of the transient recovery voltage• Restrike if current re-established >1/4 cycle
successful interruption failure (restrike)
ETRV ETRV
Circuit Breaker Performance Enhancement
ifault
vTRV
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Circuit Breaker Performance Enhancement
Contact CoordinationVoltage Gradients on Interrupter Components
E1E3
E5
E4E2
E6
stationary side -0.5 pu
moving side +0.5 pu
Contact coordination HGF1014/63 kA
02468
101214161820
0 20 40 60 80 100 120 140
gap (mm)
E (%
/mm
)
E1
E2
E3
E4
E5
E6
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Circuit Breaker Performance Enhancement
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Circuit Breaker Performance Enhancement
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Circuit Breaker Performance Enhancement
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Benefits for Power System and Equipment
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Benefits for Power System and Equipment
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� Technical and economic benefits– reduction of stresses on switched equipment leading to
life extension,– control of local transients in the substation,– local surge supression, reducing possible coupling to
the control and protection scheme,– decrease in the severity of remote transients and their
effects on sensitive loads.
Benefits for Power System and Equipment
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Benefits for Power System and Equipment
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� Suceptibility– Compromise of system of equipment function– Frequency dependent
� Mechanism– Coupling
• conductive, inductive, radiative– Modes
• common mode, differential mode
Benefits for Power System and Equipment
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� Conclusions– Effective means of reducing switching transients and
their effects on a power system and equipment• life extension• reduction of maintenance costs• system reliability• power quality
– Enhancement of circuit breaker performance– Alternative to tradition means of transient control
Benefits of Controlled Switching
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� Conclusions– Assessment depends on conditions:
• new or existing installation• planned or unplanned effects
– Driver may be:• desire to acquire experience• problem solving• preventive or corrective
– Can be used in combination with other means oftransient control
Benefits of Controlled Switching