Download Remote Black Start of Steam Electric Station

Power System Restoration
(Black Start)
Black Start Panel Session
IEEE PES Summer Meeting
Chicago, Illinois
July 23, 2002
M. M. Adibi
IRD Corp., P.O. Box 34901
Bethesda, MD 20827
[email protected]
(c) IRD 2002
Pre-disturbance Conditions
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•
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Peak load, low voltage, large network loads
Light load, high voltage, no cycling units
Long weekends (Labor Day)
Scheduled maintenance
(c) IRD 2002
Post-disturbance Status
• Complete collapse with no interconnection
assistance
• Partial collapse with interconnection
assistance
• Power system beak-up (System Islands)
(c) IRD 2002
The Three Restoration Stages
• Preparation stage, actions are time critical
(1-2 hours)
• System integration, achieving postrestoration target system (3-4 hours)
• Load restoration, minimizing MWH (8-10
hours)
(c) IRD 2002
Initial Sources of Power
• Combustion Turbines, Start-up in 5-15 min.,
probability of success 30 –50%, limited
under-excitation, use low voltage links
• Run-of-the-River Hydro, Pumped- Storage,
Start-up 5-10 min., probability of success is
high, can use HV links
(c) IRD 2002
Initial Sources of Power
(cont.)
• Once-through Units with full-load rejection,
probability of success 20-80%, maximum
elapsed time to min. loading 30 minutes,
coordinated loading problem to min. gen.
• Low Frequency Isolation Scheme (LFIS)
and Controlled Islanding, probability of
success is low.
(c) IRD 2002
Initial Critical Loads
• Cranking drum-type units, high priority
• Pipe-type cable pumping plants, high
priority
• Transmission and distribution stations, high
to medium priority depending on locations
• Industrial load, medium to low priority
(c) IRD 2002
Black Start Steam Electric Units
(Drum Type Boilers)
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•
•
•
•
Are base load units, supply large portions of demand
Max. elapsed time for hot re-start is 30-45 minutes
Min. elapsed time for cold start-up is 3-4 hours
Are remote from the load centers
Need cranking power 5-7% of their ratings
• Min. generation 25 to 30 %
(c) IRD 2002
One-Line diagram of a SE Unit
System Bus (345 kV)
GSU Taps
(5 no-load)
GSU
XFMR
Generator Bus
(18.0 kV)
Generator:
Max 185 MW
Min 90 MW
AUX Taps
(5 no-load)
SE
Gen.
AUX
XFMR
Standby Taps
(5 on-load)
Standby
XFMR
Normally Open
AUX Load Bus
(4.16 V)
AUX Load Bus
(4.16 kV)
Large Induction Motors
(350 to 6000 Horse Power)
(c) IRD 2002
Combustion Turbine Units
(cranking source)
•
•
•
•
•
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Are peaking units, supply daily peak load
Cold start up within 5 – 10 minutes
Possibility of successful start up is 1 in 3
Are close to the load centers
Need small local cranking for start ups
Hot restart within 2 – 3 hours
(c) IRD 2002
One-Line diagram of the CT Unit
System Bus (115 kV)
GSU Taps
(6 no-load)
GSU
XFMR
Generator Bus
(13.8 kV)
Twin Generators
(42 MVA, 85% PF)
AUX Taps
(5 no-load)
CT
Gen
AUX
XFMR
Local
XFMR
XFMR Taps
(5 on-load)
AUX Load Bus
(480 V)
Local Load Bus
(34.5 kV)
AUX Load
(150 kW)
Local Load
(7.5 MW)
(c) IRD 2002
A Typical Black Start System
(c) IRD 2002
Cumulative Starting & Running Auxiliaries
50
MVAR Generation
40
Start-up
MVAR Required
30
20
10
0
-10
Running
MVAR Required
-20
0
1
2
3
4
5
6
7
8
Motor Start-up Sequence
(c) IRD 2002
9
10 11 12 13 14
Conclusions
• Characteristics of steam units dictate
parallel start ups (45 to 60 minutes)
• SE units should be individually matched
with black start CT units
• Systems are sectionalized into subsystems,
each at least having one SES & one CTS
• Cranking operation uses generation,
transmission and distribution facilities
(c) IRD 2002
Recommendations
• CT units should be able to absorb line &
cable charging currents
• CT units should be able to supply reactive
power required for the start ups of large
induction motors
• Each black start operation should be
planned, analyzed/simulated, field tested
and then operators trained and exercised in
its implementations
(c) IRD 2002