Electricity and Control September 2024

TRANSFORMERS, SUBSTATIONS + CABLES

The practicalities of digitalising power distribution networks Continuing his exploration of the impact of IEC 61850 on protection and control in the field of power distribution networks, Joe Stevenson of Doble Engineering Company recently shared his latest blog post – as below – highlighting issues raised at a seminar, including concerns regarding cybersecurity.

Protecting protection and control Utilities fight back hundreds of thousands of cyberattacks every month. Cyber defences are not cheap (and in North America, NERC CIP penalties [1] are not either) on top of re covery expenses if something gets missed. Consequently, substation automation gets the attention of industry regula tors and owner-operators as it involves networks of comput er equipment serving to protect and control power systems. Obviously, these networks must be protected for the sake of system reliability. Industry players have a clear and real incentive to prioritise cybersecurity throughout substation networks anyway, but especially those at facilities operating at voltage levels that support bulk electric power delivery. Many eggs in one basket Substation automation involves coordinated integration – multiple discrete functions happening as integrated processes. In the context of protection and control (P&C), microprocessor-based (MP) relays enable automation. As programmable electronic devices, MP relays use an algorithmic paradigm for tripping built on logical (if, and, or) expressions that give protection engineers many possible ways to design advanced schemes. In due course, the intricacies of their schemes become settings in the programming of the relays. Tripping parameters of protection elements become set like so many other functions – monitoring, alarming, event capture, self

checking – all coordinated and governed by logic. MP relays receive wired inputs from instrument transformers and use wired inputs and outputs to control circuit breaker operations in their given protection schemes. Other connections (for Ethernet over copper/Ethernet over fibre) join them to networks of equipment in communication schemes that coordinate relays device-to-device using protocols that invoke redundancy among segments of the power system if local protection fails. Device-level communication schemes, such as those for P&C, contribute essential information to SCADA (supervisory control and data acquisition) aggregations at the station level. Automation rests on the capabilities of multi-function MP relays, but one significant problem complicates the whole matter: the marketplace. Manufacturers of MP relays compete on features at least as much as prices and support offerings. Customer by customer, features required within bid specifications extend what manufacturers produce, resulting in extensive capabilities being amassed along with multiple setup choices. Such expansive feature sets increase the complexity of engineering, commissioning, and maintenance, especially with relays from different manufacturers that have their own ins-and-outs regarding settings, logic, and communications.

Interoperabilty via IEC 61850 IEC 61850 and its associated standards define protocols

[Source: Doble]

Implementing IEC 61850 in digital substation infrastructures and maintaining automation through IEDs changes the game for engineers and technicians – stretching their functional areas into the domain of network specialists and vice versa.

22 Electricity + Control SEPTEMBER 2024