Future electrical power grids will require real-time control and monitoring systems to meet increasingly complex and challenging conditions. Digital instrumentation will slowly substitute conventional analogue instrumentation. New standards in the IEC 61869 series address the digital communication of electronic instrument transformers, as well as stand-alone merging units (SAMU) and digitisers for analogue instrument transformers. Following the introduction of these new standards, the transition from traditional analogue instrumentation towards the new digital instrumentation technology is expected to gain speed, both on a transmission and distribution level. To support this change, new metrological tools and methodologies are needed as test systems for this new technology. They will also be required as test systems for the performance of intelligent electronic devices like digital energy meters or real-time critical all-digital phasor measurement units (PMUs), both for AC and DC.
To ensure synchronicity between digitally-equipped substations, accurate, secure and reliable time synchronisation over a wide area is necessary. This can usually be achieved by using Global Navigation Satellite Systems (GNSS). However, in mission-critical substations, satellite-independent time dissemination and synchronisation, based on Precision Time Protocol (PTP) or White Rabbit methods, are required to provide reliability of timekeeping.
More precise synchronisation is needed within substations for SAMU timing. Providing traceable linking of timing of PTP and Pulse Per Second (PPS) signals is a challenge, as is providing the precise timing of SAMU sampling using the PTP protocol.
The deployment of digital instrumentation, along with the large-scale roll-out of smart meters, gateways and data concentrators, is already ongoing in several European countries and requires enhanced cybersecurity requirements. Furthermore, these systems generate a wealth of unused data that might be useful for other applications, part of which is yet unknown.
Full understanding of digital substations with their new digital instrumentation, both at the system level and at the subsystem level, requires digital twins of these new components. Validation of these digital twins needs to be confirmed with real measurements.
