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DAF Resources

On this page you can find resources relating to the OMG Data Access Facility standard.

The DAF is a standard software interface for accessing power system model data. More generally, DAF provides access to data in power, water and gas management systems. The acronym, DAF, stands for Utility Management System Data Access Facility.

About DAF

The DAF specification rests on CORBA and Resource Description Framework technology (RDF). CORBA enables conforming DAF clientsand servers to be written in various languages and run on a variety of platforms. RDF enables DAF servers to deal with disparate sources of data.

A recent paper presented at PICA 2001 describes some of the background. Knowledge Representation for Power System Modelling deals with the application of RDF to power system modelling and control system maintenance.

The EPRI Common Information Model (CIM) forms part of the DAF specification. DAF defines a standard means to access information in both proprietary schema and CIM schema.

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

Interfaces to update model data are not defined by the DAF. However, proposals for this extension have been made.

The Standard

The DAF standard is OMG document formal/2001-06-01 and a copies are provided here for convenience:

Complete Specification (in PDF).
Interface Defintion Language File.

The latest version of the CIM schema in RDF form is available from the CIM/XML project.

Update Extensions

An proposed extension to the DAF to permit model data updates has been discussed. The supporting documents are:

DAF Extensions for Update.
Rational Rose Model of update interfaces (also in Rose4).
IDL file for update interfaces.

Model Difference Representation

The DAF update extensions above have also been cast in RDF syntax. The Difference Models Proposal is the XML equivalent to the (CORBA) update extensions.

RDF Resources

The DAF is based on the Resource Description Framework (RDF) data model, which is a recomendation of the W3C. It also uses RDF schema.