Category / ( ) Regional Reliability Standard
( ) Regional Criteria
( ) Policy
( ) Guideline
(X) Report or other
( ) Charter
Document date / June 19, 2013
Adopted/approved by / Technical Studies Subcommittee
Date adopted/approved / August 8, 2013
Custodian (entity responsible for maintenance and upkeep) / Modeling & Validation Work Group
Stored/filed / Physical location:
Web URL:
Previous name/number / (if any)
Status / ( ) in effect
( ) usable, minor formatting/editing required
( ) modification needed
( ) superseded by ______
( ) other ______
( ) obsolete/archived)
M&VWG Priorities/Work Plan
December 2010, Updated July 2011, Updated June 2013
The following lists the M&VWG priorities in order of importance and provides a brief summary plan for meeting each priority. The items with existing or proposed WECC funding are highlighted with bold type and green color. In addition to the current and proposed WECC funding, and volunteer efforts from the M&VWG members, significant support to WECC modeling efforts is received from equipment vendors, planning software vendors, DOE, and EPRI. This support includes participation in WECC M&VWG meetings, study work, model development work, expert advice, etc.
1) Load model deployment
M&VWG plans to continue this critical effort primarily with help from volunteers from the WECC transmission planning entities, planning program vendors, and DOE funding. Some WECC funding was allocated 2010 through 2013, and is envisioned for 2014 and 2015 to further this effort as listed below.
Continuing efforts include:
· model validation studies using the composite load model
· system impact studies using the composite load model
· support for the Reliability Subcommittee efforts to understand the implications of criteria and standards
· support for the Technical Studies Subcommittee efforts to implement the new models during base case development
· support for ongoing load composition research
· support for ongoing research regarding air conditioner stalling and tripping characteristics, including additional testing and EMTP-level modeling, and potential model improvements
· workshops regarding the new composite load model have been conducted 2011-2013, and additional workshops will be provided as needed
· WECC contract with Bill Price provided an experimental single phase motor model to try to address some perceived deficiencies with the current model
· WECC contract with John Kueck provides for a report/analysis of voltage effects on various loads/load protection
· WECC MVWG maintain and enhance the tool used to estimate load composition data for summer, winter and shoulder seasons
· WECC MVWG has provided composite load model data files for the 2012 operating basecases in the 2012 study program, and will support the development of data files for future study program basecases (see implementation plan approved by TSS)
· WECC is developing a tool that detects events of Fault-Induced Delayed Voltage Recovery using synchro-phasor and digital fault recording (DFR) data
2) Power Plant Modeling
Power Plant Data Review:
There is a clear need to review the power plant model data. Data checks on the synchronous machine and exciter models showed thousands of errors. Inspection of excitation and turbine control models raises many questions. It is clear that the existing WECC Generating Unit Model Validation Policy is deficient in assuring data quality. The Power Plant Model Data Task Force was created in 2011 to ensure the quality of the power plant modeling data in grid simulation databases and to improve coordination between Generator Owners (GO) and Transmission Planners (TP). Some data issues have been resolved but there are many more to address.
Power Plant Model Verification:
· M&VWG plans to conduct workshops on MOD-025, 26 and 27, and PRC-024 NERC Standards following their approval.
· M&VWG plans to deploy Generator Model Validation Tools at WECC offices and interested utilities for power plant model verification using synchro-phasor data. The tool and processes are also one of the deliverables under WISP. The tools have been developed by BPA and are being modified to expedite the process.
· M&VWG plans to conduct workshops on generator testing, model development and validation.
WECC-0101 SAR Generator Validation:
· M&VWG has provided the recommendation to the WECC Standards Committee (WSC) on the WECC-0101 Generator Validation Standards Authorization Request (SAR) to draft a regional reliability standard or a regional variance. There is tangible evidence that the existing WECC Policy and associated documents have greatly contributed to improvement in the WECC models and the new NERC MOD standards are less stringent and will result in lower quality models and simulation accuracy. M&VWG will support the WSC as needed.
Synchronous Machine Models:
· M&VWG efforts have contributed to development of an improved model for representing synchronous generator saturation and tools for translating data to the new models, and also checking the input data for errors.
· M&VWG/TSS approved a motion to remove the gensal model from the approved model list and translate the gensal model data to the gentpj model to better represent saturation effects. The WECC Staff ran the tool that John Undrill developed under contract to translate the models and posted the revised master dynamics data file. However, there are still 4 gensal models with issues that need resolution before the translation can be finalized.
Excitation Models:
· MVWG to review the 20 approved excitation models, and determine how to reduce to a simpler set of static and rotating excitation models.
· M&VWG plans to advance modeling of Over-Excitation Limiters (OEL), Under-Excitation Limiters (UELs), and generator protection models. These are necessary for reactive power reserve studies and the studies of Fault-Induced Delayed Voltage Recovery.
Turbine Controls:
· MVWG plans to review turbine-governor models. There are signs that the modeled frequency response is again on the optimistic side. An interim baseload flag of 2 was implemented for generators that are “baseloaded” to block governor response in both upward and downward directions. A longer-term plan is to review power plant operational information and to determine what revisions need to be made to governor models to correctly represent “baseloaded” practices.
· Conversion to Kaplan models must be completed for generating units in lower-, mid-Columbia, and lower Snake rivers.
3) System Model Validation
M&VWG efforts at system model validation provided an example for the industry, but recent efforts have been limited. System model validation is essential to ongoing model improvement efforts. With current methods, creation of a base case to represent a disturbance is a significant effort. The WECC west wide system model (WSM) could provide significant assistance to WECC members in creating cases to represent disturbances, but currently there is no smooth method to transfer information available in the WSM to an environment that can be used for stability studies. Two approaches are being pursued by WECC. One is to create a dynamic data file compatible with WSM, and then simulate disturbances using WSM case. This approach will require a transient stability program to have node-breaker-element representation. Because of the program limitations and low quality of WSM cases, this approach will take several years to implement. M&VWG issued a contract with GE to provide tools and translation tables to link dynamic data available to WECC power flow base cases with system configuration, generation dispatch, and load information available in the WSM. The second option is to map generation and critical line statuses from WSM onto the WECC planning case, and then simulate disturbances in the planning environment. This is the most viable solution in the interim.
M&VWG is working with WECC RC on improvements to WSM cases through the WBRTF (WSM and Base case Reconciliation Task Force) efforts. We believe that the WSM cases are not yet suitable for transient simulations. While the network topology representation is accurate, generation and load representation are significantly deficient which impacts the validity of voltage stability analysis and dynamic simulations.
System model validation is one of the deliverables under the Western Interconnection Synchro-phasor Program (WISP). System model validation is one of the performance metrics that will be used to measure the benefits of the investment. M&VWG performed a model validation study on the July 4, 2012 event and intends to perform additional studies in CY 2013-2014 to support the WISP efforts. M&VWG also intends to develop a model validation case for the Septermber 8, 2011 event, and to develop a written process to facilitate development of model validation cases based on WSM data.
WECC M&VWG is also participating in efforts by the NERC Modeling Working Group to define power flow and dynamic system model validation methods.
4) RAS and Relay Models
TSS created the Modeling SPS and Relays Ad-hoc Task Force (MSRATF) in 2012 to improve the modeling of RAS, relays, and contingency definitions in the WECC base case. M&VWG will support its efforts and develop and approve models as appropriate.
This will include at least the following:
· Colstrip Acceleration Trend Relay (ATR)
· Over-current relays
· Over-current generation drop and separation schemes
· Power swing separation scheme
· Fast AC Reactive Insertion (FACRI)
· Jim Bridger RAS
· Under-voltage and under-frequency separation schemes
· Line distance relays
· Generator protection models
· Pacific HVDC RAS
· Event-driven RAS schemes
5) Renewable Generation Models
M&VWG plans to continue to provide review and oversight of efforts in modeling renewable generation. DOE and others are providing significant ongoing funding for these efforts while WECC funding in this area is limited.
Continuing efforts include:
· complete Phase 2 of the WECC wind modeling effort to develop improved models (especially for Type 3 wind generators) that better represent various manufacturers’ wind generators, and develop corresponding guides
· support dynamic model validation at the wind plant level; this will require installation of monitoring equipment at the interconnection points
· complete efforts to develop power flow/dynamic models for representing solar photovoltaic installations, and develop corresponding guides
· M&VWG developed and approved modeling guides for modeling distributed generation (wind and photovoltaic) in power flow models, and a wind dynamic modeling guide. M&VWG also developed Version 1 of the WECC wind generic models, and added them to the list of approved models.
· A workshop on modeling renewable generation (phase 2 wind and solar) is planned for when the models are deployed.
6) SVC and HVDC Modeling
Through WECC M&VWG efforts and efforts by the program and equipment vendors, generic static var system (SVS) models are available in major programs in use in WECC. EPRI has also contributed significantly to this effort. Approval was obtained for the SVSMO1, SVSMO2 and SVSMO3 models at the July 2011 M&VWG meeting and at the August 2011 TSS meeting. Many of the resources that have been focusing on SVS models have shifted their efforts to HVDC models, but will continue to support use of models as needed.
A high voltage DC modeling task force (HVDCTF) has been formed and there was a kick-off meeting at the July 2011 M&VWG meeting. WECC resources may be needed to support HVDC modeling. Statements of work have been developed in fall 2011.
Approved by the Modeling and Validation Work Group: June 19, 2013
Approved by the Technical Studies Subcommittee: August 8, 2013