Interconnecting substation components with optical fiber is clearly preferable to wiring them up with hundreds of individual copper cables. Not only are digital systems easier to install, they’ve proven to be safer, more reliable, and can reduce the quantity of copper in a substation by about 80 percent, a substantial cost saving.
The digital world is moving quickly, however, in tandem with new developments in primary equipment. A growing trend is the use of non-conventional instrument transformers (NCIT), such as voltage dividers or Rogowski coils combined with optical data links, and also pure optical sensors.
Smaller than conventional equipment, their linear measuring capability and higher accuracy make sensors very useful for protection and metering purposes. NCITs make a substation simpler, cheaper, smaller, more efficient and safer by replacing secondary wirings and eliminating the dangers associated with open CT circuits (Current Transformers) and of electrical hazards in general.
While ABB has been involved with NCIT technology since before 2000, a new chapter began for digital substations in 2009 when they first began adopting IEC 61850-9-2 standards for transmitting sampled analog values, which delivers a standardized interface for protection and control devices.
For example, ABB supplied more than 300 NCITs for use in Queensland, Australia more than 15 years ago, and the utility has yet to see a single failure in the primary sensor. Then in 2011, the first of six Australian substations with NCITs installed were upgraded to a new secondary system, utilizing the IEC 61850-9-2 process bus and retaining the existing primary sensors.
Site trials are being set up elsewhere as digital substation automation technology continues to advance, including the National Grid’s new 400 kilovolt (kV) Bodelwyddan substation in Denbighshire, northeast Wales in the UK. Site trials are an invaluable tool, providing information and experience that helps utilities and manufacturers develop new architecture for substation systems.
The Bodelwyddan substation site trial is designed to demonstrate how different technologies can be used at different ends of a feeder circuit using a mixture of conventional and non-conventional technology. Proving that old and new technologies can mix is vital because we are now in a technological transition period, moving from traditional copper-based installations to modern fiber-optic based systems.
National Grid is keen to investigate new technologies and processes, and ABB brings a great deal to the table, including exceptional expertise in modern digital substation systems that safely and efficiently bridge the gap between the analog and digital worlds.
The Bodelwyddan pilot is expected to yield a great many real-world benefits, including:
- a modern, future-proof substation automation system that increases performance, availability, safety and savings
- concepts and solutions that are proven and verified under real-life conditions, adding to ABB’s experience and increasing customer value
We look forward to going live with the system in the coming months.
ABB has led the charge in developing this breakthrough technology in the new millennium, applying its vast experience with IEC 61850 and NCIT technologies to create safe, intelligent, reliable, efficient, and futureproof products, while laying the groundwork for the next breakthrough.