Introduction
As utilities have deployed more and more network analysis applications such as the state estimation and contingency analysis functions of energy management systems, the steady state and transient stability functions of planning application suites, the short circuit calculations of protection software and the congestion analysis functions of market systems, silos have developed; each application frequently has its independent users, its independent model maintenance group, and its individual modeling processes and assumptions. The silos are both technical and organizational, with the resulting lack of coordination reflected in a typical network model data management picture where information comes from a variety of sources in a variety of forms, goes to a number of target systems, and whose exchange is inconsistently triggered by a variety of events. Lacking an overarching or unifying data management architecture, the creation of accurate network models relies on the experience, thoroughness and energy of utility engineers who spend significant amounts of time performing data maintenance in multiple software applications instead of system engineering.

Enter the vision of the Network Model Manage (NMM) - product ID 3002003053 - developed with EPRI and utility insight, where master data is created once and used many times - taking advantage of the International Energy Commission's (IEC) Common Information Model (CIM) interoperability standards - resulting in efficient processes throughout the utility.

The NMM provides a realistic approach to effectively handle network model data, providing a place for managing data from multiple sources going to multiple applications. Using the NMM approach reduces the level of effort to maintain models, improves the quality of analysis, and provides a seamless infrastructure on which new apps can be built; and it can be done today, as exemplified by work in progress at two utilities, American Electric Power and FirstEnergy.

The NMM Vision - Seeing Beyond the Silos

The NMM approach inserts a Network Model Manager between network model data sources and consuming applications, providing a place where data being provided to network analysis functions can be organized - a place for managing what is understood to be the one source of truth' for network model information. As shown in the figure above, data is received from substation, line and protection engineers, as well as other enterprise data sources, and is stored and managed by the Network Model Manager. The NMM then facilitates the assembly of consistent network models and cases, and their provision to the variety of network analysis applications used by planning, operations and protection engineers.

Support from a CIM'ple and Effective Data Model

The Common Information model (CIM) - product ID 3002002587 provides a basis on which a coordinated network model maintenance strategy can be built. It defines an organizational approach to network model information that reflects the fundamental nature of complex network analysis data, including:

• The distinction between physical network model data (which changes only with field activity) and case assumption data (which changes with each network analysis study);
• The common need to build network models and cases from building block' data maintained by different entities;
• The need to define prospective' changes reflective of new construction projects at utilities that may or may not be used in studies, depending on the time period being evaluated.

Because the CIM provides a solid and flexible foundation for the effective creation, maintenance and exchange of network model information to support the needs of network analysis, it is the foundation on which the NMM architecture is based.

Making It Real
During 2013 and into 2014, personnel from across the planning, operations, protection and IT domains at FirstEnergy and American Electric Power (AEP) worked together with EPRI to envision how transmission network model management at their respective utilities, and across the industry, might be streamlined. At both companies, cross-functional teams analyzed existing network model information flows, developing a detailed understanding of data flows and application inter-relationships. The feasibility of a consolidated network model management approach was explored and validated.

The teams articulated potential benefits including improved accuracy and speed of data exchange, reduction in manual efforts for validation and error correction, and the freeing up' of engineering expertise to focus more on system analysis rather than data management. Required NMM functionality was investigated and documented by means of use cases. From this work, the teams developed a high-level roadmap for each utility, and provided guidance on next steps for starting down the path toward implementation.

Collaboration Works
The cross-work group collaboration that occurred at both utilities allowed the NMM approach - a big picture' solution strategy for Transmission network model maintenance - to be validated. It also illustrated the pervasiveness of the disjoint model maintenance problem at utilities throughout the world and the widespread applicability of an NMM-based architecture for improving the situation.

"It certainly appears we have influenced the industry on a vision for network model management, as evidenced in a vendor road-mapping the functionality," said Donna Bursick, Director, IT Real-Time Operations at FirstEnergy.

Eric Hatter, who works in EMS Applications Support at AEP, echoed Bursick's enthusiasm, "Integrated Network Model Management is no longer a nice to have' idea, but is CRITICAL for utilities who plan to thrive in today's regulatory and competitive environment!"

Encouraging a Product-Based Solution
The universality of both the network model management problem and its solution strategy set up a true product development opportunity: an industry with a widespread need, a need that could be satisfied by a configurable software tool, a tool that could be sold to many utilities. Recognition of the NMM product niche, however, has been thwarted by siloed thinking'; some may not recognize the magnitude of the problem or the feasibility of the solution; others may have difficulty perceiving the potential size of the NMM product market and the full range of functionality such products need to support. The glimmers of interest in an improved network model management would need an industry-wide boost' to allow the NMM product niche to attract serious vendor product investment.

Spurred by decisions on the part of both FirstEnergy and American Electric Power to move forward with network model management improvement initiatives, EPRI launched a Network Model Manager requirements overview project, believing that it would benefit everyone (the utilities, their selected vendors, the industry at large) if the solutions being implemented were viewed as the deployment of a widely useful product that had been intentionally designed to serve the needs of network model consumers throughout the utility organization. The approach taken to encourage the vision was to engage a critical mass of interested participants to help define the essential functionalities a quality network model management tool should have and to the share results of the work freely and widely.

Spreading the Word
Through the collaborative efforts of eight utilities and two vendors, the NMM requirements that had been identified during the American Electric Power and FirstEnergy deep-dive projects were explored, refined and augmented. A collection of common use cases, reflective of typical ways in which a Transmission System Operator (TSO) or Independent System Operator (ISO) might use a NMM tool in managing its network models, were explored and documented. The use cases led to the identification of eight high-level requirements for a network model management tool:

1. Provides a secure, redundant permanent store for physical network model parts;
2. Manages the identities of network modeling objects in different contexts;
3. Supports multiple workspaces for carrying out NMM operations in parallel;
4. Provides capabilities for users to browse and edit NMM content in variety of ways (graphical, tabular, individual items);
5. Supports the IEC CIM modular concept for assembling network models and network analysis cases;
6. Supports the development of a testing and validation regimen;
7. Provides CIM-based integration services that support integration with other systems without requiring amendment of NMM product code;
8. Supports a data-driven and extensible data model, definable by an accepted information model.
    

Happening Now!
The detailed results of the collaborative Network Model Manager Requirements project are available in the Network Model Manager Technical Market Requirements document, downloadable from the EPRI website. Additional information about CIM support for network analysis data is available in a recently published EPRI report, Using the CIM for Network Analysis Data Management, also available from the EPRI website. And webcast recordings of four training sessions on the CIM's support for network model data are available at the UCAIug YouTube Channel.

In Conclusion
The utility industry has an opportunity to significantly improve how it manages its network models. Coordinated NMM architecture-based network model management, underpinned by the CIM data model, provides a feasible and realistic way to efficiently manage network model data originating from multiple sources and going to multiple consuming applications. This approach offers sizable potential benefits in reduced engineering labor and increased accuracy of utility network models. It offers even greater promise in creating the seamless network model infrastructure on which forward-looking T&D applications will be built, and it can be done now.
 

About the Author

Pat Brown, Principal Technical Lead, Information and Communication Technology in EPRI's Power Delivery and Utilization program, has more than 25 years of experience supporting electric utility control center applications. She is currently engaged in a range of projects leveraging industry standards, including the Common Information Model (CIM), in the deployment of data sharing solutions for transmission. Pat serves as the lead U.S. expert on IEC TC57 Working Group 13 (CIM for Transmission) and as the EPRI liaison to UCA International. She has a B.S. in Architecture from the University of Michigan is a certified Project Management Professional.