Reducing the Distance to Integrate: DTE Energy’s Use of the CIM at the Integration Layer
Grid-Interop Forum 2012
Dr. Gerald R. Gray, Kelly Flowers
Electric Power Research Institute (EPRI)
942 Corridor Park Blvd, Knoxville, TN 37932
DTE Energy
One Energy Plaza. Detroit, MI 48226-1279
,
Grid-Interop Forum 2012
Gray, Flowers
Keywords: CIM, ESB, Integration, Enterprise Architecture, Standards
Abstract
An information model such as the International Electroctechnical Committee (IEC) Common Information Model (CIM) can be helpful in reducing the distance to integrate. This “distance” is usually reflected in the cost; using a proprietary, customized interface recognized as being the most expensive, while a “plug and play” is the least costly both in term of the initial investment as well as the cost of ownership. As utilities gain integration maturity and governance it is often useful to leverage a data reference model such as the CIM at the mediation layer between applications, usually via an enterprise service bus (ESB) [1].
In this white paper the genesis of using the CIM at the ESB to integrate applications at DTE Energy will be explored. This exploration will include CIM preparation (training), refactoring IT governance, the value that has been derived from using the CIM, and lessons learned. This paper will also briefly describe DTE Energy’s plans for maintaining the interfaces and the strategy for updating to new versions of the CIM as they are released.
1. Introduction
While the Common Information Model (CIM) has long been a useful resource as a data reference or semantic model, the criticism has often been that it lacked guidance on how to use it for integration. To a certain extent this criticism was valid. The analogy most often used was that the “CIM is a dictionary, not a writing guide”. This was due to the fact that data elements were identified and described within profiles (subsets of the model used to describe a particular useful function) that could be used for integration, but there was limited guidance on how to do the integration.
As the CIM became recognized as a useful data reference model and as service-oriented architecture (SOA) was recognized as facilitating the development of open, interoperable advanced metering infrastructure (AMI) solutions [2], utilities, products vendors, and systems integrators began asking for practical guidance on how to use the CIM in systems integration.
In this environment DTE Energy, a Michigan-based utility began looking at improving their back-office integration capability and maturity, and looked at the CIM as one of the resources that could help them achieve their goals.
2. Setting the stage
2.1. Common Information Model (CIM)
The Common Information Model (IEC standards 61968 [3], 61970 [4], 62325 [5]) provides a common data reference model for distribution utilities. It should be kept in mind that each of these standards is not a single document but is described in total as part of a family of documents. For example, IEC 61968-1 describes actors and the interface reference model of systems that are typically used within a utility. IEC 61968-9 leverages IEC 61968-1 but delves into the specifics of meter reading and control. Additionally, while a given document will describe the use cases, interactions, and provides an XML Schema Definition (XSD)[6] that defines a profile, each of the CIM standards is also represented in a data reference model in Unified Modeling Language (UML). A profile is a subset of the model that describes some useful information. These profiles are often used for exchanging messages. At the time that DTE Energy began their CIM exploration the only integration guidance that was available was IEC 61968-1 1st Edition (2nd Edition will be published early in 2013, as will IEC 61968-100 Integration Guidance for 61968) and the consensus has been that the 1st edition did not provide enough integration guidance (hence the need to develop 61968-100).
2.2. Enterprise Service Bus (ESB)
As Service-Oriented Architecture (SOA) began to be recognized as a useful way to integrate systems and in turn the use of ESBs also grew as stakeholders recognized that a bus was a significant improvement over the situation with point-to-point interfaces; reducing the cost of maintenance and increasing agility. However, an ESB is not a panacea. If there is low maturity in the development of interfaces, introducing an ESB does not solve that problem. For example, if there is low maturity in deciding what interfaces are built, how and if they leverage prior art (reuse) an ESB does not solve that problem. It does facilitate reuse because by design the intent is that once an interface has been built it can be used by any application needing similar information. Additionally, by using orchestration (combining multiple services) new business capabilities can be developed from existing services. So, while an ESB provides benefits such as routing, mediation, service orchestration, or event-based processing, to fully benefit from an ESB an organization also needs a high degree of governance maturity. For example, reviewing information architecture (to leverage resources such as the CIM) or other references, or determining where services already exist that can be leveraged rather than building a new service from scratch each time that a work request comes in.
2.3. Reducing the Distance to Integrate
This concept comes from the Gridwise Architecture Council paper that describes integration capability and maturity [7]. In addition to describing an architecture “stack” this paper also put forth the idea of reducing the “distance to integrate”.
Figure 21 Reducing the distance to integrate, adapted from Gridwise Architecture Council Context Setting Framework
The idea is that the most expensive way, from both a development and maintenance way of doing integration, is to have a completely custom interface. This is represented in the figure above. As interfaces leverage SOA and can be reused, this reduces the distance to integrate because an interface does not need to be created from scratch but can be reused or remapped. Going one step further, if both sides of an interface use a common data reference model, then the requirement for transformation is minimized, further reducing the distance to integrate.
3. The DTE Energy Experience
DTE Energy, an electric and gas utility based in Detroit, MI, serving approximately 2.1 million electric customers and 1.2 million gas customers, began their investigation of the CIM in 2009. The company’s SOA uses Java Web Services that leverages an ESB. Since the adoption of CIM, DTE Energy has continued to build their Enterprise Semantic Model (ESM) using a requirements-driven approach rather than doing a wholesale update to all interfaces. Message structures are added to the ESM as requirements arise for new interfaces to new systems or legacy systems. The ESM is used to transform messages to the ESM if the legacy systems are involved.
DTE Energy began its CIM investigation and adoption in the spring of 2010. Since then there have been 15 interfaces using the message structure and that number is continuing to grow. The number of CIM compliant interfaces and the number of messages in the ESM are planned to increase in 2013 and 2014 with the upgrade of some of the enterprise solutions and the rework of the existing interfaces.
3.1. Challenges
When DTE Energy first brought in the CIM not everything went as expected, especially when considering that the integration guidance at the time that DTE began was somewhat immature. It took time and resources to get support for this effort. There is still some push back on the use of the CIM and the ESB. Changing a fundamental architecture can be as much about changing organizational culture as it is about changing the technology. Changing a culture is difficult and to many people within the organization this effort seemed like a big change. Every business domain believed that they were different and do not readily fit into a common model. They also had issues with seeing the overall benefit of moving forward with this approach and primarily see the failure points and extra upfront work. Once there were a few interfaces in place (successes) some people began to see the benefit and buy into the change but there is still a lot of work to get everyone comfortable and engaged.
In the mid-1990’s John Kotter [8] developed an eight step process for successfully managing change in an organization. It is easy to recognize alignment with Kotter’s change management process at work that enabled success at DTE Energy; i.e. creating a guiding coalition, communicating vision, building change that aligns with the vision, and creating short-term wins. However, given that, if they could do it over again DTE Energy would:
• Build out domain areas based on areas of the business.
This would allow for the company to identify smaller areas to focus on ESM development and where CIM fit. It would also give them a defined business model of how their business is made up and where the overlaps occur.
• Look at other information models to build out the ESM.
CIM fit many aspects the DTE Energy business on the electric side but there were gaps identified relating to the business needs of the gas utility. However, these were easily remediated by extending the model. It did not and still does not fit all aspects of the business. There are efforts underway to harmonize other models with CIM to remediate some of these gaps. Developing an ESM would have been much easier if other information models had been identified to fill gaps in the CIM. This is also where the defined domain areas would be useful. With the business model defined, identification of models for the individual areas would have been easier and DTE Energy would have been better at identifying where CIM fits and where it does not.
• Dedicate an effort to develop the ESM.
DTE Energy has a team dedicated to the development of Enterprise Services but not the overall ESM. The Enterprise Services Development team will add to the ESM as requirements arise but they are not working towards defining the overall ESM. Having this prepared beforehand with defined messages in a library, development of new services for new integration points would benefit earlier in the lifecycle. This should be a dedicated effort to define the corporation’s model instead of piecing it together as they go.
• Improve communication on the value of the ESB and CIM.
There has been a lot of push back around the use of the ESB and even around the use of CIM. The belief is that this stems from a lack of understanding of how both work and the benefits that can be achieved.
• Participate more in the CIM User Group.
DTE Energy has been involved in the CIM User Group but on a fairly limited basis. There is value that could have been added and received in that participation. Because the participation has been limited, the company only has a couple of people who know and understand how to use the CIM and can give feedback on future releases.
• Take advantage of help from other entities.
Many utilities have adopted the CIM for modeling their electric distribution business and have a tremendous amount of learning based on that experience. Many companies including utilities have built out their ESM and have also learned from that experience. DTE Energy did not take full advantage of the help that these companies were able and willing to offer. They could have benefitted from the lessons learned around the process of developing an ESM using industry standards such as CIM.
3.2. Value
There has been value added in the use of CIM and the ESB. Part of the value seen is the lowered distance to integrate. The pieces of the lowered distance to integrate that DTE Energy has seen are time to delivery, total cost of ownership, common knowledge of the model, and common integration patterns. The enterprise has seen the time to delivery of services using CIM and the ESM decrease. With an established message structure, time does not need to be spent on developing and obtaining agreement on a message structure. There is an upfront cost to implementing the CIM message for the first time and determining what part fits for that use case but the total cost of ownership is less because that initial effort is not repeated for every new interface or change.
Developers also learn the structure and there is a common knowledge of how to use CIM and existing messages that exist in the ESM. With the established use of CIM, development of an ESM and the introduction of an ESB, a common integration pattern has emerged that also builds on the lowered distance to integration. DTE Energy has seen value in having a repeatable pattern for integrating systems while reducing the coupling between those systems.
DTE Energy has also seen value in this approach outside of lowering the distance to integrate. Adopting CIM for their electric distribution model provided the basis for the ESM. There is still significant work to do to move the ESM forward but DTE Energy has already seen value in the small portion that has been developed.
The CIM has become an industry standard for electric utilities and is growing to accommodate more parts of the business. This adds value to DTE Energy by facilitating interoperability, if needed, with outside partners who have also adopted CIM. CIM has facilitated the standardization of business terms and make these terms common across business areas. It has allowed the company to speak the same language within its own walls.