CTS – CIM Topology Store Implementation of an RDF-based versioning system for the CIM using the topology difference model Mathias Uslar Arnhem, Netherlands xx

2 Agenda Adressed problem Use Cases Used technologies Solving the problem Implementation Results Further work

3 Adressed problem Data must be exchanged between grid providers –Narrowly meshed grids –New challenges for utilities Power grids are constantly evolving –Changes have to be tracked and made persistent Serializing the grid using XMl leads to bloat –High amounts of data –Difficult to be validated

4 Use Cases We have identified four main use cases for our system Regular exchange of full topology models Exchange of partial topology models Recombining partial topologies to create a full one Tracking and versioning topology histories

5 Used technologies – Semantic Web XML –eXtensible Markup Language RDF –Resource Description Framework OWL –Web Ontology Language SPARQL –SPARQL Protocol And RDF Query Language –Query language for RDF Semantic Web Stack (Quelle: W3C)

6 Technologies – Common Information Model Focus: Representing topology data CIM is serialized in RDF Markup of the PsyCor-SmallModel (Source: CIMPhony by Dr. Alan McMorran, University of Strathclyde) <rdf:RDF xmlns:rdf=" xmlns:cim=" HANGER18 AIRPORT VL_AIRP_345..

7 Solving the problem – the difference model Evaluating the existing format according to deVos –Non-conform to the RDF-standard –Uses syntax with insertion and deletion operations Developed and evaluated two new formats –Conforming the RDF-standard –Evaluating replacement and insertion and deletion approaches –Improved parsing for machines –More robust due to pre- and postconditions

8 Example: changing a load BRADFD 0 true 0.2 Solving the problem – Difference model BRADFD 0 true 30 BRADFD 0 true 0.2 Differenzformat nach deVos Differenzformat dahlem Difference format dahlem

9 Solving the problem – regional model According to Britton: Designing Model Exchange Processes with CIM and ’RMA Sets’ Three types of regions: –Base region –Border region –Aggregated region Regional model (Source: Britton, Areva T&D

10 Solving the problem – Versioning and SPARQL Versioning system –Absed on the difference format –Implements the regional model SPARQL query system –Querying of versioned topologies –Supports aggregated regions

11 Our solution The new formats are more standard-compliant (RDF), more robust than the existing one and incorporated more information There was no known existing solutions for versioning topologies in CIM (end of 2006) There was no known implementation of the regional model for CIM (end of 2006)

12 Implementation Backend system Web Services –Apache Tomcat –Apache Axis Database MySQL Jena –RDF-Triple-Store for MySQL –Java API SPARQL implementation Command line client VMWare for Windows/Linux System overview (Source: Own graphic)

13 Results Compatibility to other CIM implementations –Interop #6 tests have been passed completetely Improved difference formats: –More robust –RDF-compliant –More information Implementation fo a versioning system and the regional model More functionality: –Validating against CPSM (2.0, experimental 3.0) –Notification ( , Jabber)

14 Further work Improving the client –GUI for endusers Keeping data solely as RDF –Technology breach: versioning data is kept in a relational database Benchmarks –RDF-Triple-Stores are too slow nowadays SPARQL has a lot potential for improvements –„The next SQL“ –Current research: DML & DDL, algebra

15 Thanks for listening Time for questions