Download PSRC C17 WG Russ Tra..

IEEE PES PSRC – C17 Joint WG
“Wind Plant Short Circuit Contributions”
Turbine & Aggregate Plant Short
Circuit Considerations with respect to
Power System Protection
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Russell Patterson
Travis Smith
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Outline
• Wind Power Plant & Substation Designs
• Overview of Five Wind Turbine types
• Need for Protection based Wind Turbine models
• Transmission Planning Software
• Power System Protection software
• 20% Wind by 2030, some concerns
– 30,000 MW now, 300,000 in 20 years
– System protection and Wide Area Coordination
– Grounding systems and protection
– FERC #661 Ride Through & Dynamic Models
– Power Quality, Harmonic Resonance
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Wind Power Plants Designs
• WPP plants range from single to hundreds of WTG’s
• Collection systems consist of many miles of underground
and over-head lines at p to 34.5 kV
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Wind Plant Substation Designs
Wye – Wye - Delta
©2009
Delta - Wye
Wye – Delta with Effective
Grounding Transformer
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Wind Plant Interconnection Switchyards
• Many Substation &
Switchyard
configurations
connecting wind plants
to the Grid
• Often, due to time
constraints, these get
scaled down to Three
Terminal Lines
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Overview of Five Different WTG types
WTG comparisons to conventional generators:
• Smaller and connected at Low or Medium Voltages
• Machines are Asynchronous or Synchronous
• Some Protective Relay functions have been incorporated
into the WTG Control Systems
• Usually proprietary and not easy to obtain
• Main Overcurrent Protection is typically within the
WTG LV or MV Circuit Breaker
• All WTG’s have auxiliary power which can be
significant over a large wind plant
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Type I – SCIG Wind Turbine Generator
• Turbine is fixed to grid frequency
• Generates with negative slip
• Soft starter for reduced inrush
• PFCC’s for IG reactive support
• Locked-Rotor fault contribution
ranging from 5pu to 6pu
• Short circuit represented as
voltage source in series with the
direct axis sub-transient
inductance, Xd”
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Type II – WRIG Wind Turbine Generator
• Turbine is fixed to grid frequency
• Generates with negative slip
• Soft starter for reduced inrush
• PFCC’s for IG reactive support
• Locked-Rotor fault contribution
ranging from 5pu to 6pu
• When rotor is shorted by rotor
resistance the short circuit is
represented as voltage source
in series with sub-transient Xd”
•When rotor resistance is at
maximum the representation includes
rotor resistance
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Type III – DFAIG Wind Turbine Generator
• Variable frequency excitation
system for rotor circuit, FourQuadrant Converter adjusts rotor
current and phase angle quickly
• Back-to-Back converter exchanges
power directly with the grid
• Wide Speed Range, Real
& Reactive Power Control
• If crowbar is not active
SC is limited to 1.1pu rated
• If crowbar is active SC model is a
voltage source in series with Xd”,
locked rotor of around 5 to 6pu
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Type IV – Full Converter Wind Generator
•Four-Quadrant full frequency
converter
• Turbine fixed to turbine side converter
frequency
• Real & Reactive Power Control
• Short Circuit limited to 1.1pu rated
power
• Line side converter
can only contribute
positive sequence current
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Type V – Synchronous Wind Generator
• Synchronous generator coupled
with variable speed drive train
and torque & speed controls,
4 to 6 pole designs
• Shaft speed converted
from variable to constant
speed which is coupled to
the generator
• Synchronized with the
grid frequency through sync-check
relay, protection, & circuit breaker
• AVR control of synchronizing system
• Unbalanced short circuit representation depends on grounding of the
generator, can range from no zero sequence to more than 3PH fault values
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Need for Protection based WTG models
• ANSI Std., larger Induction Machines should be
considered in short-circuit calculations
• Wind plant Designers, Owners, and Consultants
need Short Circuit Models of WTG for:
• Sizing, Protection, & Coordination
• Overhead and underground lines & cables
• Buses, structures, grounding, etc…
• Transformers
• Circuit Breakers
• Capacitor & Reactor Banks
• Dynamic Reactive Compensation
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Transmission Planning Software
• WTG’s models created for Planning Software:
- PSLF, PSS/E, PSCAD, Others…
- Contributors include: IEEE Standards, WECC,
ERCOT, NREL, UWIG, Others, etc.
• Planning models are needed but are “Planning”
specific and do not offer much to the System
Protection Engineer for performing system
protection and coordination studies.
• IEEE-421.5 is being used for WTG models
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Power System Protection Software
• Short circuit models of WTG’s are necessary
• WTG’s should be modeled and wrapped into
larger Utility Power System & Protection models
for use in future protection studies, relay
coordination, and wide area coordination
simulations
• Some of the Protection Software Packages: CAPE,
ASPEN, Easy-Power, SKM, CYMTCC, MilSoft
Windmil, ETAP, EDSA, Transmission-2000, S&C
Web-based Coordinaide, SIGRADE, etc…
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Power System Protection Software
Opportunities exist with respect to the Planning
software models as well as EMTP/ATP models
• DOE Awarded SBIR Grant, Electrocon Intl.
Created a program that would allow
communication between PSS/E transient
stability simulations with CAPE protective
relays and zero sequence, for analyzing
protection schemes in CAPE with dynamic
network simulation results from PSS/E
• Electrocon Intl. also created a similar
communication link between ATP/EMTP
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Power System Protection Software
Since PSS/E has the Generic Wind Turbine
Library, developed by ERCOT, WECC, NREL
• Research possibility of C17 WG contributions to a
separate effort which may include working with
CAPE, ASPEN, PSS/E, PSCAD, EMTP/ATP, etc..
• The integration of Planning & Protection
Commercial Software Packages may be the ideal
way to create and help maintain dynamic short
circuit models for use in Protection software
packages through IEEE
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
United States Wind Plants (Commissioned & New)
• Current Wind Energy Rated Capacity is approximately 31,612 MW
• DOE Vision is 20% Wind by 2030, approximately 300,000 MW
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
System Protection & Wide Area Coordination
Short Circuit Models are needed for Protective Relay Studies.
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Grounding Systems and Protection
Temporary Overvoltage Conditions
during a SLGF on the collector
circuit, before and after fault
instance and breaker TRIP
Transfer Trip is an option for
fast clearing.
Grounding
Transformer
©2009
Breaker with Integral
Grounding Switch
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
FERC #661 & Dynamic WTG Models
Transmission connected Wind
Plants are now required to ride
through and recover from
transmission level 3PH faults.
System relay coordination &
checking will be more precise with
future software connections to PSS/E
& EMTP WTG dynamic model
results
- High Side Transmission Fault Strong System
Per-unit Voltage
Per-unit Current
Weak System
Per-unit Voltage
©2009
Per-unit Current
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Power Quality
• Harmonic Resonance can be an
issue with vast underground XLPE
cable systems, static capacitor
banks at the substation, and
sometimes PFCC in turbines.
• Many Permutations…
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group
Questions?
©2009
IEEE PSRC C17 “Short Circuit Contributions of Wind Plants” Joint Working Group