Time in Communication Networks, Protection and Control Applications

Summary

This webinar is based on the CIGRE Technical Brochure 884. General trend is movement towards more intelligent and accurate monitoring and protection systems. In the substation environment these are IEC61850 based applications and wide area monitoring systems that rely on accurate time and synchronization. Today we can see that time distribution has become an essential part of modern power grids.

Satellite GNSS systems are commonly used because they can easily provide accurate timing. Multi constellation systems with several antennas provide redundancy, but there are still known vulnerabilities. Most of the possible vulnerabilities related to time over the air transmission can be mitigated by using fiber connections and PTP.

PTP has several profiles and some of them are targeted to sub station use. Also devices can have different operating modes. In large scale system hierarchical design is recommended where different profiles and modes can be combined. All of these leads to situations where careful design and acceptance testing are needed. Also, continuous monitoring of time and synchronization is recommended to ensure proper operation.

PACS requirements for synchronization vary a lot from 1us to 1s depending on the application. It’s important to understand needed accuracy requirements and plan compliant systems and at the same time avoid too complex and costly solutions.

Additional informations

Video

Speakers

Antti Viro

Keywords

Time Synchronization, GNSS, PTP, Clock references