1. Network (Common) Model Management System Presentation to ERCOT October 21, 2008 Thomas F Garrity Vice President Energy Management and Automation Siemens Energy Inc Presentation to ERCOT October 21, 2008 Thomas F Garrity Vice President Energy Management and Automation Siemens Energy Inc

2. Page 2 © 2008 Siemens Power Transmissions & Distribution, Inc. All rights reserved The Problem  Transmission Network planned operational changes must be submitted, evaluated for regional reliability, approved or rejected, and put into service through a managed process between an ERCOT and member T&D Companies or other transmission service providers  The existing processes are not fully automated and, therefore, labor intensive and time consuming.  Lack of uniform, automated electronic coordination also provides opportunities for data errors in model changes through data translation between applications and companies.  Model inconsistencies between or within organizations cause inaccuracies in reliability evaluation  Partially automated processes and inconsistent models cause a significant direct negative bottom line impact.

3. Page 3 © 2008 Siemens Power Transmissions & Distribution, Inc. All rights reserved The Solution: Siemens – Network (Common) Model Management System (NMMS)  A single coordinated master data source providing capability to feed mission critical Operations, Maintenance and Planning applications  Provides integrated tools to efficiently coordinate the workflow followed in managing transmission network changes for the ERCOT and TSO’s  Electronic submittal of planned network model changes in a standard format  Supports automated process for electronic approval or rejection  Integrated tools enable rapid modification and resubmission of rejected plans  Supports convenient secure electronic access to approved plans  Provides for integrated managed coordination of TSO planned network changes with operations for the development of commissioning plans  Support Audit and Dispute Resolution

4. Page 4 © 2008 Siemens Power Transmissions & Distribution, Inc. All rights reserved Siemens CMMS Operating ModelPlanning Model Operating ModelPlanning Model Market Operations Settlement Outage Evaluation EMS CRR Auction Actual Network Changes Accurate External Network Model Planned Network Changes Planned Change Approval, Rejection Transmission System Owners Approved Plans T&D Service Provider Approved Plans Current Operations Model Approved Planned Network Changes Current Operations Model Shadow Settlement EMS Load Management Reliability Analysis Dynamic Energy Analysis Congestion Analysis Transfer Limit Analysis Fault Analysis Approved Plans:  Plan 1 T&D 1  Plan 2 T&D 1  Plan 1 T&D 2  ……..  Plan m T&D n Reliability Analysis Operations Planning Transfer Limit Analysis Congestion Analysis Fault Analysis As-built/ Archived Models  Model day 1  Model day 2  Model day 3  ……..  Model day n

5. Page 5 © 2008 Siemens Power Transmissions & Distribution, Inc. All rights reserved Model on Demand - MOD® Built for Planners  Data submitters can enter known in- service or effective dates for each future system expansion or improvement project  Enables user to build a model for any specific date into the future.  The User needs to submit a project only once and it is available for all case build timeframes on or after the project’s effective date.  Users can Download case, project, profile, ….etc. Data from the application  Receive activity Logs including case create details.

6. Page 6 © 2008 Siemens Power Transmissions & Distribution, Inc. All rights reserved Information Model Manager  Quickly create and maintain an accurate Power System Model  Incrementally merge network model modifications  Fulfills NERC data exchange requirements  CIM-compliant data import and export enables data migration from existing data stores and exchange in standard formats  Automatically maintains an audit trail  Data Reporting enables users to create predefined or user-defined reports  Graphical topology verification and editing  Performs initial validation on connectivity, equipment uniqueness, and basic constraints

7. Page 7 © 2008 Siemens Power Transmissions & Distribution, Inc. All rights reserved Case Builder Operational Model Case Builder  Create cases and models for various applications  System-wide dissemination of data modifications ensures a consistent Power Systems Model for all applications  Support internal and external data exchange needs  Utilizes supplemental data to create cases (e.g. contingencies, outages, market data)  Each target system has a profile that defines data to be consumed  A back end API converts Operations models to Planning models

8. Page 8 © 2008 Siemens Power Transmissions & Distribution, Inc. All rights reserved CMMS Value Proposition/Benefits  Significantly Reduced workload for ISO/RTO and T&D Planning and Operations Staff  Better control and accuracy of the Operating Model leading to improved reliability management of the overall transmission network (RTO and T&D)  Improved Model accuracy leads to improved accuracy of congestion management and resultant settlement financial solution by the RTO  Improved Model provides accurate external network models for TFO operations  Provides a well synchronized method and tools to and initialization planning models from the current operations model