Midwest ISO creates largest state estimator power model in U.S.

Tom Mallinger, Midwest ISO

Talk about a team effort.

The Midwest ISO’s (MISO) Market Model Development teams in Carmel, Ind. and St. Paul, Minn. have been working non-stop to design, test and complete Midwest ISO’s network model in time for market systems integration testing.

According to MISO Network Models manager Kala Seidu, who heads up the project, kudos go to the Network Modeling teams, the Operations Engineering team, Operations EMS Applications team and IT Engineering Applications team for their contributions to the success of the node-breaker model development and state estimator implementation work.

The Market Model Development teams’ work is essential to the successful implementation of market operations because the network model will be used for locational marginal pricing (LMP) calculations and to create the base models for financial transmission rights (FTR) allocation processing. Two other MISO activities use the node-breaker or real-time network model and the state estimator results. First, the Operations staff utilizes the real-time network model and state estimator results to monitor the state and security of the MISO member transmission systems in the MAIN, ECAR, MAPP and SPP regions. Second, a project is underway to migrate the application that calculates available flowgates capacities (AFCs) for the Operations horizon to the MISO node-breaker model.

Prior to March 2003, the teams successfully integrated the MAIN, ECAR-MET, SPP, Michigan Electric, and Manitoba Hydro control area node-breaker models into a single centralized MISO model. After achieving a valid power flow solution on the resulting centralized model, the teams mapped ICCP (Inter-Control Center Communications Protocol) measurements from the MAIN, ECAR-MET and Michigan Electric control areas to the model and successfully tuned the state estimator. And because the above models came from different EMS systems, one of the challenges for the teams was converting the models from the CIM (Common Information Model) format to the Alstom ESCA database format.

Since March, the MISO Network Model teams have achieved the following:

“- Completed the conversion of the MAPP Phase I network model from CIM format to ESCA database format and integrated this model into the centralized MISO model. The MAPP Phase I model enhancement work involved the expansion of the MAPP node-breaker model to include critical 69kV systems in Xcel Energy, Dairyland Power Cooperative and Southern Minnesota Municipal Power Agency. The team also completed the mapping of the ICCP measurements for the MAPP Phase I areas into the centralized MISO model. This model has been put into production and the state estimator has been solving consistently, reliably and robustly.

“- Completed the mapping of ICCP or real-time telemetry data to the combined network model to make it possible for the state estimator application to solve on the combined model.

“- Completed expansion of the MAPP Phase II model, adding critical 69kV systems in Alliant West, Michigan Electric, Omaha Public Power District, Nebraska Public Power District, Western Area Power Administration, Ottertail Power, Great River Energy, Minnesota Power and Montana-Dakota Utilities control areas to the existing MAPP node-breaker model. The resulting model was converted from Siemens database format into CIM format and from CIM format into ESCA database format. The converted MAPP Phase II model was successfully integrated into the centralized MISO model and a valid power flow solution has been achieved on the resulting centralized model. Midwest ISO’s Network Models teams are currently mapping ICCP measurements from these areas in the MAPP region to the centralized model.

“- In April 2003, the team replaced the representation of the Ameren transmission system in the centralized MISO model with a new model provided by Ameren. The reason for the replacement was to reflect recent transmission system changes made by Ameren. A valid power flow solution has been achieved on the resulting centralized model and Midwest ISO is currently mapping the Ameren ICCP measurements to the resulting centralized model that also contains MAPP Phase II model enhancements.

“- Significantly upgraded the representation of the Cinergy transmission system in the centralized MISO model to reflect the transmission system upgrades made by Cinergy.

The target date to have the production state estimator running on the resulting centralized model was (at press time) May 30, 2003. The centralized model will consist of approximately 100 control areas, more than 16,000 substations, 25,000 buses and more than 3,600 generating units. More than 38,000 ICCP measurements will be mapped to the model. Approximately 50 percent of the ICCP measurements are digital or breaker status measurements. The other 50 percent is comprised of analog measurements such as line flows, transformer flows, generating units MW outputs, load measurements and voltage magnitude measurements.

The state estimator application solves every 5 minutes and the real-time contingency analysis application solves every 15 minutes. Each time it runs, the contingency analysis application solves more than 4,000 contingencies.

The Network Model activities scheduled to occur after May 30, 2003, include:

“- Updates to the representation of the NIPSCO transmission system;

“- Updates to the representation of the Louisville Gas & Electric transmission system;

“- Updates to the representation of the Tennessee Valley Authority transmission system;

“- Mapping of ICCP measurements from the Manitoba Hydro area to the centralized MISO model; and

“- Continuous updates to the centralized MISO model to reflect ongoing transmission changes in other areas of the MISO transmission system, including American Transmission Co., Indianapolis Power & Light, Madison Gas Electric and Illinois Power, etc.

Mallinger is director of operations, engineering security, MISO. He may be contacted at tmallinger@midwestiso.org or 317-249-5421.

Author

  • The Clarion Energy Content Team is made up of editors from various publications, including POWERGRID International, Power Engineering, Renewable Energy World, Hydro Review, Smart Energy International, and Power Engineering International. Contact the content lead for this publication at Jennifer.Runyon@ClarionEvents.com.

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The Clarion Energy Content Team is made up of editors from various publications, including POWERGRID International, Power Engineering, Renewable Energy World, Hydro Review, Smart Energy International, and Power Engineering International. Contact the content lead for this publication at Jennifer.Runyon@ClarionEvents.com.

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