IEC 61850-9-2 based sampled values and IEC 61850-8-1 Goose messages mapping on an FPGA platform

Abstract

Electricity substation monitoring and control systems have evolved over the years from simple systems capable of achieving minimalistic functions to autonomous, self-healing smart grid schemes (Farhangi, 2010). The migration of technology to networked smart grid systems was driven by the need for standardisation of communication networks, system configuration and also the reduction of system implementation costs and engineering time. Before the introduction of a uniform communication standard, legacy (non-standardised) communication protocols, for example, the Distributed Network Protocol (DNP3) were used by Remote Terminal Units (RTUs) for information exchange (Luwaca, 2014). These communication protocols could not provide a standard naming convention or data semantics since the data/information was accessed using an address-based system. The implementation of automation systems based on legacy protocols and RTUs was expensive because of parallel copper wiring required to connect instrument transformers and circuit breakers to multiple RTUs for protection and monitoring functions (Iloh et al., 2014). Legacy systems refer to Supervisory Control and Data Acquisition (SCADA) systems implemented using RTUs and legacy communication protocols. Legacy systems tended to be vendor specific because devices from different vendors did not support the same communication protocol. These issues led to the introduction of the IEC 61850 standard. The IEC 61850 standard for “communication networks and systems in a substation” provides standardised naming convention, data semantics, standardised device configuration and also device interoperability and interchangeability in some instances. The IEC 61850 standard provides a solution to expensive parallel copper wiring and standardisation issues experienced with legacy protocols. In as much as the introduction of the IEC 61850 standard addresses problems experienced with legacy system there is still a need to provide inexpensive access to IEC 61850-compliant devices and effective knowledge transfer to facilitate implementation of automation systems based on this standard. The development of an IEC 61850-compliant device requires a specialised skillset and financial investment for research and industrialisation therefore only a few vendors manufacture these devices resulting in an increase in production and manufacturing costs. For this reason this research project develops VHDL modules for mapping IEC 61850-9-2 Sampled Value (SV) messages and IEC 61850-8-1 Generic Object Oriented Substation Event (GOOSE) messages on a Field Programmable Gate Array (FPGA) platform. Sampled values are used for transmitting current and voltage transformer (CT and VT) measurements to protection devices while GOOSE messages exchange information/commands between primary equipment (CT, VT and circuit breaker) and protection devices over an Ethernet network known as the process bus.