Precise timekeeping is fundamental to the function of the power grid and is used in many applications to improve reliability, reduce costs, predict and prevent faults, and check operation of devices. As such, the power grid requires precise time synchronization across system-wide devices, often with sub-millisecond accuracy.
To accomplish this, extremely precise satellite clocks serve as the time source for the network time protocol, and the information is distributed to the other devices on the network. In fact, satellite clocks are standard within electric utility substations and at certain distribution line locations.
Despite being extremely accurate, utilities are continuously seeking even greater precision in timekeeping. Luckily, advancements in satellite clock design and programming can enhance accuracy. Currently, the accuracy is pushing towards achieving a margin of plus or minus 20 nanoseconds.
Utilities anticipate significant benefits from the improved accuracy, including more precise location of faults, multi-rate billing, power-flow monitoring, and event reconstruction.
Companies continue to invest in research and development to achieve even incremental improvements in clock accuracy in the sub-millisecond range.
“While any satellite clock can access satellites as a time source, the hardware and software within the satellite clock can make it more precise and accurate. So, in addition to previous utility solutions, we offer timekeeping devices,” says Nathan Irvin, product manager of networking products at NovaTech Automation, a leading U.S. provider of automation and engineering solutions for power utilities headquartered in Quakertown, PA.
The company’s latest release, the Kronos Series 3 satellite clock, provides multi-constellation support with several upgraded features including antenna-cable delay compensation.
By building antenna cable-delay compensation into the algorithms for calculating time, along with multi-constellation support, the company is able to provide best in class accuracy. The master clock is able to achieve 20 nanosecond maximum time deviation while locked with the satellite.
According to Irvin, there are many applications in the power grid that can benefit from more precise timekeeping including:
• Multi-rate billing: Typically required accuracy: 0.5 to 1 second.
• Event reconstruction, sequence-of-events (SOE): Typically required accuracy: 1 to 5 ms (sub-cycle of the 50/60 Hz sine wave).
• Power-flow monitoring: Typically required accuracy: 1 to 10 μs.
• Traveling wave-based fault location: Typically required accuracy: better than 1 μs (for a 300 m fault location accuracy).
• Integration of Renewable Energy Resources, which require synchronization of when power/how much power is added to the line.
For more information on solutions for a continuously evolving power grid from NovaTech Automation, visit www.novatechautomation.com or call (913) 451-1880.