Download Standpipe Presentation TSS

Standpipe Synchronous Condenser
and South-Central Wyoming Voltage
Coordination
Presentation to WECC TSS
May 8, 2015
– PacifiCorp customers in South-Central Wyoming system have
been exposed to unacceptable voltage performance on a
number of occasions.
– To remedy this issue, PacifiCorp is implementing several
system improvements, including a new 65 MVA synchronous
condenser at Standpipe substation, relocation of an existing
31.7 MVAr shunt reactor to Standpipe, installation of a new
25 MVAr shunt capacitor at Latham substation,
implementation of droop control at area wind farms, and
implementation of coordinated shunt device control at
numerous substations.
© 2011 PACIFICORP | PAGE 2
Introduction
Wyoming 230 kV System
< 230 kV Existing
230 kV Existing
Pumpkin
Buttes
345 kV Existing
230 kV Proposed
Badwater
Midwest
Antelope
Mine
TOT4A
Riverton
Wyopo
Casper
Atlantic
City
DJ
Spence
Difficulty
Bairoil
Mustang
TOT4A
Shirley Basin
Freezeout
Miners
Bridger
Rock Springs
Point of
Rocks
Platte
Latham
Aeolus (Future)
Standpipe
Foote
Creek
© 2011 PACIFICORP | PAGE 3
White
Horse
(future)
Firehole
Windstar
Latigo
South Central Wyoming Wind
< 230 kV Existing
230 kV Existing
Pumpkin
Buttes
345 kV Existing
230 kV Proposed
Badwater
Midwest
Antelope
Mine
TOT4A
Riverton
Wyopo
Casper
Atlantic
City
DJ
Spence
Difficulty
Bairoil
Mustang
TOT4A
Shirley Basin
Freezeout
Miners
Bridger
Rock Springs
Platte
Latham
Point of
Rocks
Foote Creek
135 MW
Dunlap
111 MW
Aeolus (Future)
Standpipe
Foote
Creek
Seven Mile
118.5 MW
High Plains
127.5 MW
© 2011 PACIFICORP | PAGE 4
White
Horse
(future)
Firehole
Windstar
Latigo
Dave Johnston Area Generation
< 230 kV Existing
230 kV Existing
Pumpkin
Buttes
345 kV Existing
230 kV Proposed
Badwater
Midwest
Antelope
Mine
TOT4A
Riverton
Wyopo
Atlantic
City
DJ
Spence
Difficulty
Bairoil
Mustang
TOT4A
Shirley Basin
Freezeout
Miners
Bridger
Rock Springs
Point of
Rocks
DJ
795.8 MW
Platte
Latham
Aeolus (Future)
Standpipe
Foote
Creek
© 2011 PACIFICORP | PAGE 5
White
Horse
(future)
Firehole
Windstar
Latigo
Casper
Windstar
Area Wind
537.5 MW
– Wind generation interconnected on the DJ to Point of Rocks
230 kV line tends to flow west (away from DJ).
– The Platte to Standpipe 230 kV line acts as a funnel for area
generation, and sees the highest line flows in the region.
– Flow above 475 MVA is possible under maximum wind
conditions.
– Flow on this line segment is directly correlated with wind
generation output from Foote Creek, High Plains, Seven Mile,
and Dunlap, and line flow can vary significantly with wind
generation output.
© 2011 PACIFICORP | PAGE 6
Voltage Performance
Voltage Performance (ctd.)
© 2011 PACIFICORP | PAGE 7
– As generation output in the area varies, line load fluctuates
above and below the surge impedance load of the line,
resulting in large, relatively slow voltage swings.
Voltage Performance (ctd.)
© 2011 PACIFICORP | PAGE 8
– THE PERFECT STORM:
– High voltages are seen in the area when the DJ to Difficulty
line is open in conjunction with low wind conditions.
– The DJ to Difficulty outage results in an approximately 200
mile-long, radial, lightly-loaded 230 kV line.
– During low wind conditions, area wind farms have little or no
regulating capability.
– With the tie to DJ open, there is very little short-circuit MVA.
Standpipe Project






Installation of a new +65 / -40 MVAr synchronous condenser at
Standpipe substation.
Relocation of an existing 31.7 MVAr shunt reactor to Standpipe.
Installation of a new 25 MVAr shunt capacitor at Latham substation
Implementation of droop control at area wind farms
Implementation of coordinated shunt device control at Latham, Platte,
Miners, and Standpipe.
Decommissioning of the Foote Creek DVAR and implementation of
power factor control of the shunt caps at Foote Creek.
© 2011 PACIFICORP | PAGE 9
– To remedy voltage issues in the region, PacifiCorp is
implementing several system improvements under the
Standpipe project, including the following:
– Several dynamic reactive device technologies were investigated for
Standpipe, including Static VAr Compensators (SVC), Voltage-Sourced
Converters (STATCOM), and Synchronous Condensers.
– The synchronous condenser was selected based largely on technical
criteria
 The Wyoming 230 kV system is heavily shunt compensated, and
voltage instability was a concern with an SVC installation.
 System inertia relative to transfer levels (stiffness factor) in the region
is very low.
 To date, STATCOM installations on the PacifiCorp system have not
proven reliable, and difficulties were encountered procuring a
STATCOM.
 The voltage swings in the region tend to be relatively slow, therefore
speed of the device was not a significant factor.
© 2011 PACIFICORP | PAGE 10
Standpipe Synchronous Condenser
Standpipe Synchronous Condenser
– There are several advantages of a synchronous condenser for this
application.
 The condenser is a rotating machine, and adds inertia to the system.
 Control of the device is relatively simple and is not impacted by
system configuration or future system upgrades.
 Linear output characteristic.
 Very few power quality issues.
• Voltage drop from starting was a concern; however a pony motor will be utilized to
start the device.
Coordination with local area wind farms can be managed with droop
settings.
– There are also disadvantages associated with a condenser
 Losses
 Maintenance requirements
© 2011 PACIFICORP | PAGE 11

– The Miners shunt capacitor and Standpipe shunt reactor will
be utilized to expand the available dynamic capacity of the
condenser.
– The scheme will utilize the shunt devices to bias the
synchronous condenser output to a value near the center of its
dynamic capability (+15 MVAR). As the Standpipe
synchronous condenser has a continuous output capability
between -40 MVAR and +65 MVAR, the bias point at +15
MVAR will effectively provide +/-50 MVAR of available
reactive capability to respond to system voltage fluctuations.
© 2011 PACIFICORP | PAGE 12
Standpipe Condenser Dynamic Expansion
Standpipe Condenser Dynamic Expansion
– The Miners and Standpipe shunt devices will be controlled by
the condenser as follows:
Standpipe Synchronous
Condenser Output
+60 MVAR
+50 MVAR
+45 MVAR
Insert Miners Capacitor
+40 MVAR
Trip Standpipe Reactor
+30 MVAR
+20 MVAR
0 MVAR
-10 MVAR
Trip Miners Capacitor
-20 MVAR
-30 MVAR
-15 MVAR
Insert Standpipe Reactor
© 2011 PACIFICORP | PAGE 13
+10 MVAR
Latham
1x25 MVAr Cap
© 2011 PACIFICORP | PAGE 14
Wyoming Shunt Device Coordination
Platte
2x25 MVAr Cap
2x27 MVAr Cap
© 2011 PACIFICORP | PAGE 15
Wyoming Shunt Device Coordination
Miners
1x27.6 MVAr Cap
© 2011 PACIFICORP | PAGE 16
Wyoming Shunt Device Coordination
Standpipe
1x31.7 MVAr Reactor
65 MVA Condenser
© 2011 PACIFICORP | PAGE 17
Wyoming Shunt Device Coordination
Foote Creek
6x5 MVAr Cap
3x6.67 MVAr Cap
© 2011 PACIFICORP | PAGE 18
Wyoming Shunt Device Coordination
Wyoming Shunt Device Coordination
© 2011 PACIFICORP | PAGE 19
– Shunt devices at Latham and Platte will be controlled locally utilizing
coordinated switching setpoints and time delays.
– Shunt devices at Miners and Standpipe may be set to control local voltage
utilizing coordinated switching setpoints and time delays; however their
primary mode of operation will be the condenser dynamic expansion
scheme.
– Shunt devices at Foote Creek will be controlled to minimize VAr
exchange to the 230 kV system, with 34.5 kV voltage supervision.
Wyoming Shunt Device Coordination
– Shunt devices will be controlled utilizing a dual-band control philosophy.
Insert Reactor or Trip
Capacitor with Fast
Time Delay Setting
Vhi-fast
Insert Reactor or Trip
Capacitor with Slow
Time Delay Setting
Vhi-slow
Slow Control
Deadband
Fast Control
Deadband
Trip Reactor or Insert
Capacitor with Slow
Time Delay Setting
Trip Reactor or Insert
Capacitor with Fast
Time Delay Setting
Vlow-fast
© 2011 PACIFICORP | PAGE 20
Vlow-slow
© 2011 PACIFICORP | PAGE 21
Questions
– Questions?