Western Electricity Coordinating Council
Modeling and Validation Work Group
Progress Report to TSS
February 2015
The WECC Modeling and Validation Work Group (M&VWG) meeting, Renewable Energy
Modeling Task Force (REMTF), and Load Modeling Task Force (LMTF) meetings were
held in Albuquerque, NM on November 18-20, 2014. REMTF was held the afternoon of
Nov 18 and the morning of Nov 19, LMTF was held the morning of Nov 19, and M&VWG
was held the afternoon of Nov 19 and all day of Nov 20.
The following topics were discussed at the M&VWG meeting:
I. Next Meetings and Workshops
II. Load Modeling
III. Renewable Energy Modeling
IV. System Model Validation
V. Generator Modeling, Testing, and Model Validation
VI. HVDC Modeling
VII. RAS and Relay Modeling
VIII. NERC Updates
IX. WECC Project Updates
X. Approved Dynamic Model Library and Status Update of Models
XI. Program Updates: GE PSLF, PSS®E, and PowerWorld
XII. Other – WECC Website Feedback
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I. NEXT MEETINGS AND WORKSHOPS
The next MVWG meeting is planned to be at Salt Lake, UT on March 17-19, 2015. The
REMTF will be held the afternoon of March 17 and the morning of March 18, the LMTF
will be held the morning of March 18, and M&VWG will be held the afternoon of March
18 and 19 all day.
A possible WSM validation workshop is being discussed for June 2015. Another possible
workshop is on the tools for Power Plant Model Validation. It was also discussed to
coordinate with RAS modeling workshop that WECC staff is planning to organize.
II. LOAD MODELING
A) Composite Load Model – Model Specifications
Bill Price went over the CMPLDW Model Specifications Document. There are additional
comments such as from Fred Howell (PowerTech) that has not been addressed in the
distributed document. The team decided to postpone the approval to the March 2015
meeting.
B) Composite Load Model – Benchmarking test
At the June meeting, Dmitry Kosterev (BPA) suggested and sent the test case for
benchmarking across software platforms to ensure consistent implementation of the
Composite Load Model. Jamie Weber (PowerWorld) presented the testing results that
were performed by study engineers in BPA, University of Illinois, and PacificCorp. There
were bugs identified and fixed through this exercise. Jamie also made his point that due
to the result reporting differences, some results may appear differently but are
fundamentally identical. On a high level, the implementations of the Composite Load
Model across different platforms are consistent.
Jamie also discussed the difference between MOTORW and induction motor models
(CIM5, CIM6, CIMW, and MOTOR1). For single-cage motor where Tppo=0 or Lpp=Lp, all
these models are identical, and historically MOTORW had input data that represented
single-cage motors only. PowerWorld used to assume the MOTORW worked the same
as CIM 5, and starting July, 2014, PowerWorld has added an option to change to the
alternative induction motor block diagram used for MOTORW.
C) Composite Load Model Monitoring Improvements in Software Implementation
Jun Wen (SCE) presented several PSLF user desired functions for running the Composite
Load Model studies.
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One is the Load Tripping Monitoring function that allows the users to view the total load
loss and the load loss broken down by type (MA/MB/MC/MD/PE/DG) per
load/zone/area/owner. Bill Price (GE) shared the load tripping monitoring specification
document based on the requirement, and indicated that this function has been
implemented and is currently under testing.
Another two are related to the fact that the CMPLDW moves the load to a fictitious bus
after initialization of the power flow case in PSLF. One is the inability to locate the load
record using the original bus number and perform the load drop function in the otg-d
file. Brian Thomas (GE) indicated that PSLF has already fixed this in the latest release.
The other one is the bus variable name change at the original load bus from a load-bus
to a non-load bus. The users would still like to see the original load bus as the load-bus.
The purpose to differentiate the bus variable name between the load bus and non-load
bus is to allow users to apply different criteria when performing the Worst Case Analysis
(WCA) in the plot.
The presented user desired functions specifications document is specifically for PSLF,
but the other two software platforms PSSE and PowerWorld are also required to have
the equivalent capabilities. Jay Senthil (PTI) and Jamie Weber (PowerWorld) indicated
that they will look into the load tripping monitoring function. The fictitious bus is not
reported out to the users in both PSSE and PowerWorld and therefore no further
actions are required from this regard.
D) Composite Load Model – Load Composition Data Tool
Pavel Etingov (PNNL) gave a demonstration on the enhanced Load Composition Data
Tool. This tool is developed based on the previous excel tool, and now has better user
interface. The tool is available for whom is interested at using and testing the tool from
Pavel. He also indicated that the tool will be soon released for public use and test.
E) WECC-0100 Project Update and Transient Voltage Criteria
The group reviewed the WECC-0100 TPL-001-WECC-RBP-3 System Performance
document that was posted for comments. There were suggestions on clarification on
some of the draft languages, as well as discussions on the technical basis. Baj Agrawal
(APS) suggested that the group submits comments with clear expectations or
explanations.
III. RENEWABLE ENERGY MODELING
Pouyan Poubeik (EPRI) provided an update of the REMTF work.
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A) White paper on limitations of generic models
The generic models deployed in the positive sequence program are not applicable to
low short-circuit ratio scenarios. The model specifications documents typically specify
the range of the model, but the users may not pay attention to it and often have
questions to software vendors. It was agreed that REMTF including three software
vendors will develop a white paper on describing the limitations of generic models.
Pouyan will lead and draft the white paper.
B) Energy Storage Modeling
Two thirds of the energy storage modeling is available with the newly developed 2 nd
generation renewable models. The battery module still requires development. REMTF
hasn’t made progress due to other ongoing work. Utilities with energy storage projects
have expressed desire to have the model available sooner. Shengli Huang (PSE) will work
with interested utilities including Jun Wen (SCE), Hassan Ghoudjehbaklou (SDGE),
Spencer Tacke (MID), Brandon Phan (SNOPUD), and some others to kick-off and speed
up the energy storage model development, while collaborating with REMTF.
Xiaokang Xu (S&C) commented that there is an energy storage model package available
from S&C website.
C) Plant Level Control
The high-level plant controller work is in progress. Pouyan Pourbeik (EPRI) will put
together a brief model specification document based on discussion at the meeting, and
circulate spec to GE, Siemens PTI, PowerWorld, and S&C for comments. Once the spec is
agreed, software vendors will implement a beta version for testing. The goal is to have a
beta version for testing end of 1st or 2nd quarter in 2015.
D) SVSMO3 Validation and Applications
Xiaokang Xu (S&C) presented the applications and validation of SVSMO3 in transmission
planning studies. The study results proved that the model is working properly.
E) Transition Plan for Renewable Models
The target completion date to remove the Phase 1 models is June 5, 2015.
Stephanie Lu (SCL) will work with Abe Ellis (Sandia) to send request letter to renewable
generation manufactures for the default data to be used in the Phase 2 models.
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F) Integrating DGs in Composite Load Model
It was agreed by REMTF and LMTF to have the DGs in the Composite Load Model. The
model is named as CMPLDWG. CMPLDW will be retired upon implementation and
approval of CMPLDWG.
Bill Price (GE) presented the “WECC Specifications for Modeling Distributed Generation
in Power Flow and Dynamics”. There are different opinions as to how to model DGs in
power flow (load scaling or MW independent), and different opinions as to how to
initialize P and Q from power flow. Jeni Mistry (SRP) will follow up the discussions. The
plan is to have the specifications for approval in the March 2015 meeting.
Song Wang (PacificCorp) will coordinate the benchmark testing among the three
vendors for CMPLDWG. The target is to present the results in the June 2015 meeting.
IV. SYSTEM MODEL VALIDATION
A) JSIS Update
Dmitry Kosterev (BPA) provided an update on the JSIS activities. The WISP investment
portion was completed 1 year ago, and now partnering with DOE and stakeholders on
system events and power plants validation using PMU data. The WISP project is also in
the process of moving to the second phase which is a 2 year project. There were
proposals selected by DOE, which include data quality improvement, voltage stability
analysis (V&R ROSE is selected), and model calibration. There are several work groups
under JSIS. A few applications such as voltage stability analysis and oscillation detection
have already been installed at Peak RC and BPA.
Dmitry Kosterev and Steve Yang (BPA) have also reached out to other utilities, to set up
a joint task force/user’s group between JSIS and MVWG with focus on power plant
model validation using disturbance data. A few members have started using the Power
Plant Model Validation tool that was developed by BPA.
B) Model Validation Studies
Dmitry Kosterev (BPA) presented the May 16 2014 NW AC RAS event and the model
validation results. The report was approved by MVWG on Aug 12 2014. There are
another two events that are under validation studies: May 26 2014 DC RAS event, and
June 12 2014 BCH RAS and Alberta separation event. Brian Thomas (GE) and Slaven
Kincic (Peak RC) agreed to perform the study and plan to present the results in the
March 2015 meeting. They also plan to present the model validation process. Dmitry
also indicated that there was nothing significant since the May 26 event, and he will
continue to share with the group as event occurs.
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The following items are further discussed from the validation study for May 16 2014
event:
 The wind modeling needs improvement. Peak RC has been working with the
owner utilities on improving those models.
 The Springville unit tripped during the event and the cause requires further
investigation from SRP.
 The Chief Joseph Brake operated during the event which may be unnecessary.
Hamody Hindi (BPA) talked about the original intention for the Chief Joseph
Brake scheme, and indicated that the current design may have departed from
the original intention. BPA is currently reviewing the scheme, and plans to
present results in the March 2015 meeting.
 Guihua Wang (BCH) provided an overview on Kemano RAS, which was the RAS
that operated during the event. After reviewing the RAS under this scenario,
some changes are being made.
C) MOD-033
Dmitry Kosterev (BPA) suggested the group to start thinking about how WECC plans to
comply with NERC MOD-033. A conference call will be scheduled after the meeting to
kick-off this effort. The interested parties include: Slaven Kincic (Peak RC), Dmitry
Kosterev (BPA), Lucas Boler (BPA), Hamody Hindi (BPA), Doug Tucker (WECC), Jun Wen
(SCE), Baj Agrawal (APS), Jeni Mistry (SRP), Hassan Ghoudjehbaklou (SDGE), Stephanie
Lu (SCL), Roberto Favela (EPE), Pouyan Pourbeik (EPRI), Song Wang (PacificCorp), Jay
Senthil (Siemens PTI), Shawn Patterson (USBR), Brian Thomas (GE).
D) WBRTF Update
Slaven Kincic (Peak RC) provided update on WBRTF efforts. 95% of generation MW has
been mapped in the WECC. He also mentioned that he has worked with BPA and Idaho
Power on modeling consistency between the planning case and WSM EMS case.
E) Node-Breaker Model Development
Brian Thomas (GE) showed the PSLF v19 node-breaker capability, and how PSLF v19 can
be used to take WSM case and WSM dynamic file which is mapped from the planning
dynamic file to run the validation study.
Slaven Kincic (Peak RC) showed the benchmarking test results between the PSLF busbranch model and WSM node-breaker model. There are differences between the two.
Brian showed the comparison of the model behavior versus the actual recordings. After
the tuning the governor response of some generators, the simulation results have a
good match to the actual recordings.
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V. GENERATOR MODELING, TESTING, AND MODEL VALIDATION
A) Power Plant Model Data Task Force
Kent Bolton (WECC) reviewed the dynamics error list. Kent also showed the renewable
generation modeling status from the master dynamic file that was prepared by Eric
Bakie (Idaho Power) from the last MVWG meeting, where some of the wind generation
was represented with genrou. Stephanie Lu (SCL) mentioned that Eric Bakie (Idaho
Power) has developed a tool to export the generator turbine type from the powerflow
data and all the dynamic models associated with each generator in a single spreadsheet
which can be used to examine the modeling.
B) Excitation System Models
Shawn Patterson (USBR) provided an update on the IEE 421.5. It is close to going out for
ballot. A stator current limiter was recently added to the standard.
C) Cross Current Compensation Model
The CCOMP Model Specifications and adding CCOMP to Approved Dynamic Model list
was unanimously approved.
Pouyan Pourbeik (EPRI) and Shawn Patterson (USBR) commented that the behavior of
the CCOMP as implemented in the existing platforms is different from reality. They will
work together and come up with the specification of a more accurate model with a
different model name, if warranted. The plan is to present the model specifications at
the March 2015 meeting.
D) Power Plant Model Validation
Steve Yang (BPA) presented the Power Plant Model Validation tool that was developed
by BPA. The tool is available for other interested members to use. Some set up work is
initially required for the tool to work, and Steve is willing to help. This is related to the
Power Plant Model Validation task force user group that BPA is trying to set up to
promote the use of PMU data for power plant model validation.
E) Frequency Response
Hamody Hindi (BPA) presented some experience with combined cycle unit frequency
response and temperature dependency.
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VI. HVDC MODELING
Pouyan Pourbeik (EPRI) provided an update on HVDC modeling.
The task force document is in progress (rev 3/14), the next update will be soon. For the
line commutated HVDC point-to-point dynamic model, the user-written version was
done and tested, the next step is to pass to commercial vendors for implementation.
The VSC HVDC point-to-point powerflow model was done and tested, and will be in next
release of commercial tools (already in PSSE). The VSC HVDC point-to-point dynamic
model is still in discussion phase.
VII. RAS AND RELAY MODELING
Stephanie Lu (SCL) provided an update on the MSRATF activities, including relays, RAS,
contingency definitions, node breaker topology, and sequence component network
modeling. The MSRATF has dissolved, and activities are moving to TSS’s Joint Users
Group (JUG), MVWG, and SRWG, etc.
Donald Davies (WECC) is looking into the RAS modeling for transient studies.
Fred Howell (PowerTech) presented PowerTech’s experience with modeling RAS in
transient stability. The RAS modeling from PowerTech has been used in CAISO, and is
also currently under evaluation by Peak RC.
Eric Bahr (NWE) provided an overview of the Colstrip ATR scheme and the model
specifications. Eric will work with PowerWorld, PSSE, PSLF, PowerTech, and Colstrip
Owners to get the model implemented. The ATR model specification and the ATR model
are expected for approval at the March 2015 meeting.
VIII. NERC UPDATES
Eric Allen (NERC) provided an update on the NERC standards and NERC MWG group
activities. The Disturbance Monitoring Equipment standard PRC-002 was approved by
Member Ballot, and on the way for board approval. The MOD-032, 033 standards were
approved by FERC.
NERC MWG has developed drafts of two documents addressing the first two tasks of the
node-breaker implementation plan.
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IX. WECC PROJECT UPDATES
Shawn Patterson (USBR) briefed the team that the WECC-0107 project (PSS Design and
Performance) is in the process of responding to the comments from the 2nd round, as
well as the WECC-0101 project (Generator Validation Conversion).
X. APPROVED DYNAMIC MODEL LIBRARY AND STATUS UPDATE OF MODELS
Stephanie Lu (SCL) and Kent Bolton (WECC) reviewed the approved dynamic model
library. Comment will be added to the 1st generation wind models that their approval
will be removed from the list, expected in June 2015. The CCOMP model will be added
to the Approved Dynamic Model list.
Jun Wen (SCE) will update the “Status of WECC Models” document to include sections
describing the WECC approved documents and available tools. The purpose is to serve
as a MVWG reference document to the users.
XI. PROGRAM UPDATES
GE PSLF, PTI PSS®E, PowerWorld, and PowerTech provided program updates.
XII. OTHER – WECC WEBSITE FEEDBACK
Many MVWG members raised concern that it is very hard to locate MVWG documents
at the new WECC website. The group believes that a MVWG page is needed for the
group documents, which at a minimum should include the approved documents, model
specifications, and tools. Kent Bolton (WECC) will relay the issue to WECC IT technical
department.
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