Langdale Consulting and Technical Services

CIM/XML Resources

On this page you can find resources relating to the CIM/XML language.

The CIM/XML language is a language for representing power system models. It has been adopted by the utility industry body, NERC, as the standard for exchanging models between transmission system operators.

A recent paper presented at PICA 2001 describes the CIM/XML language, its application and its development.

There is a discussion group for this standard. The members of this group conducted their first interoperation trial in December 2000 and have performed more since. There is a press release announcing this event. (The official version for printing is a zipped RTF file.)

The Specification

CIM/XML is an application of the W3C's Resource Description Framework (RDF). It consists of a profile, sub-setting the RDF syntax and an RDF schema derived from the EPRI Common Information Model (CIM) for power systems.

The EPRI CIM in UML form is maintained by IEC Technical Committee 57 Working Group 13.

The subset of RDF Syntax is designed to simplify serializers and interpreters while retaining compatibility with existing RDF tools.

The CIM RDF schema completes the specification. The schema is derived from the CIM Rose Model.

Incremental Model Transfer

Power systems are subject to constant change and there is a need to publish and process a set of model differences, distinct from the complete model. Such incremental model transfer is useful where the base model is very large or the model changes themselves are subject to checking and other steps before use in the live EMS.

The CIM/XML group is adopting a difference model definition for this purpose. Some examples have also been created.

Message Oriented Middleware

Message Oriented Middleware is increasingly used to connect the major information systems in a power utility. The message definitions often contain items that have been defined in the CIM.

A tool has been created to generate XML Schema message definitions from the CIM. A straw-man message definition shows how the generated schema is used in a message schema.

Resources

A validator kit has been prepared based on the Stanford RDF API. Download and usage instructions are provided.

A tool to extract the RDF schema for CIM from the Rational Rose file, called Xpetal, is also available. Both tools are maintained on sourceforge.

There is a related OMG standard called the Data Access Facility, or DAF. This is a set of CORBA interfaces for CIM model information. (And, by extension, any RDF data.)

The RDF, and RDF schema are recommendations of the W3C