Integration of legacy intelligent electronic devices in UCA based digital control systems

Intelligent electronic devices (IED) are the standard protection and control equipment in today´s substations. UCA2 based protection and control systems integrate devices that are designed to support the UCA object models. However, there is a huge installed based of legacy protection and control IEDs that are still going to be available for many years and will have to be integrated in UCA based systems. The paper describes in detail the complex object model of multifunctional legacy protection and control IEDs. The models are based on the existing UCA 2 documents (Generic Object Models for Substation and Feeder Equipment - GOMSFE). It presents the basic building blocks and their grouping in order to model such a protective device. The challenges of modeling different multifunctional legacy devices in a single gateway are discussed. The object-oriented approach to peer-to-peer communications for high speed protection and control functions and issues related to gateway based applications are covered in another section of the paper. They are based on Generic Object Oriented Substation Event (GOOSE) messages exchanged between protective relays connected to the substation LAN.