Design & Implementation of a Universal Communications Processor for Substation Integration, Automation and Protection

Substation Automation (SA) is a rapidly increasing area of interest in Electrical Engineering these days embracing numerous benefits to utilities. It is clearly the most dynamic and exciting new development in the substation industry with the ultimate goal of efficiently managing operations, maintenance and capital assets with minimal human intervention [1-4]. Intelligent Electronic Devices (IEDs), which are Instrumentation & Control (I&C) devices built using microprocessors, are the most important elements of a SA system. An IED is primarily used as a monitoring, control, protection or data processing device with at least a single serial communication interface. Substation IED networking requires the ability to remotely control, manipulate and monitor newly connected devices through the use of an effective communication system used to link various IEDs in a substation. The existence of a wide variety of vendor specific and hardware-oriented solutions as well as different communication techniques used for the communication between devices had previously stopped utilities from achieving a fully integrated and interoperable SA system. The idea of standardising the language of communication between IEDs has evolved as the key for the advancement of connectivity and interoperability within a SA system. As a consequence, Institute of Electrical and Electronics Engineers (IEEE) and International Electrotechnical Commission (IEC) have been developing SA standards based on Object-Oriented (OO) technologies. IEC 61850, the main topic of discussion in this thesis, is such a standard developed by the IEC Technical Committee (TC) 57. It describes how devices are to communicate in a substation as well as the related system requirements. It features support for all substation functions and their engineering with the use of OO data and service models [5]. However, it has only been abstractly modelled meaning that it focuses on describing what the OO models are indented to provide rather than how they are built. Consequently, the IEC 61850 standard can only be operational when mapped to a specific concrete application layer protocol such as the Manufacturing Message Specification (MMS) or ISO/IEC 8802-3, which are the two communication services put forward by the IEC 61850 standard. The primary objective of this research is the OO implementation of the IEC 61850 standard as a concrete application layer protocol running on a middleware platform designed and implemented in a communication processor environment. In this research, the IEC 61850 implementation is founded on the C/C++ programming language development of the standard�s Abstract Communication Service Interface (ACSI) Object and Service Models (OSMs) as concrete programs based on their published definitions, hence transforming the IEC 61850 standard into a solid protocol. An alternative to the present implementation practice, the mapping process as proposed in the IEC 61850 standard, is recommended where virtual representations of real devices can be modelled and implemented at the application layer of a communication processor making use of the OO implemented OSMs of the standard itself rather than using the equivalent models of another application layer protocol. Middleware is a software layer that resides between the operating system and the applications allowing multiple processes running on different machines to interact over a network. Middleware design is based on architectural issues concerned with the organisation, overall structure and communication patterns dictated by applications as well as the middleware itself [6-7]. This thesis describes the design and implementation of a new middleware architecture aimed at providing diverse communication methods to IEC 61850 related applications. The designed middleware is of the Message-Oriented Middleware (MOM) category and considers the fact that communicating entities may take on different roles such as client/server or peer-to-peer, therefore allowing for different interaction modes such as synchronous invocations and asynchronous message passing. Several simulation studies are also presented in this thesis to demonstrate how IEC 61850 applications can be built at the application layer of a communication processor as well as to test and evaluate the performance of the middleware architecture implemented within the same communication processor environment. Time synchronisation, which involves synchronisation of the date and time of all devices in a network, is another key topic discussed in this thesis. Time synchronisation is crucial in time-sensitive substation applications and its importance has been clearly acknowledged by the IEC 61850 standard as a requirement. The implementation and integration of the Simple Network Time Protocol (SNTP) and its applications into the overall communication processor architecture is another feature proposed in this thesis in order to facilitate the time synchronisation of applications designed in this research. Ultimately, the development of a gateway capability that permits for the testing and evaluation of the designed components over a real network is described. The designed and implemented "Hardware in the Loop" (HITL) capability mainly provides the necessary interface between the real Ethernet network and the simulation environment enabling two or more simulations running on separate computers to be linked together