An IEC 61850 synchronised event logger for substation topology processing

Substation automation systems consist of intelligent electronic devices (IEDs), substation computers, and the communication network between them for implementing control, protection and monitoring tasks in substations. This paper presents a topology processing technique that uses substation event information captured from legacy IEDs using a logging device. Such a device accurately translates the IEDs'process-level control signals into a binary data representation using non-intrusive current transducers. The data is then transmitted using Generic Object Oriented Substation Event message format, which is defined in the latest substation communication standard IEC 61850. The device also implements IEEE 1588 standard to provide synchronised time-stamp values for each translated binary data within sub-microsecond accuracy. The event data obtained by using the logger on legacy IEDs is combined with data obtained directly from IEC 61850 compliant IEDs in processing the real-time substation topology. The proposed system could overcome existing problems of supervisory control and data acquisition systems, such as inaccurate timing information of substation events and unreliable topology processing in presence of bad data. Preliminary test results that demonstrate the operation of the new system are presented in the paper.