This makes it possible to eliminate a protection vulnerability in power grids.
SIPROTEC5 process bus dataflow deepblue 4 3 ISO2 medium
In digitalizing power grids, especially in the increasingly widespread digital substations, precise time synchronization is essential for protection and control systems. This enables critical protection functions to operate without interruption and ensures an uninterrupted electricity supply for consumers, including households.
A new solution represents a step forward in this field, as it not only increases the reliability of power grids but also eliminates a cybersecurity vulnerability.
The role of synchronization
Time synchronization means that all communication-capable devices must operate on the same time base, down to the microsecond level.
To receive the time signals that form the basis of timekeeping, traditional electrical protection devices "only" require globally accurate time signals, such as those provided by Global Navigation Satellite Systems (GNSS). However, in so-called process bus systems—which connect intelligent electronic devices with primary equipment in modern digital substations—the correctness, and even the interpretability, of the measured values primarily depend on consistent local accuracy rather than on external global time signal sources.
In addition, external time signal sources may be vulnerable to certain natural phenomena (such as solar storms) or intentional interference, which can lead to "time base jumps" in the time used as the reference value.
In the event of such disturbances, or even during the transition between standard time and daylight saving time, substation systems are forced to resynchronize themselves in order to align again with the time used as the reference. However, this may require temporarily shutting down critical protection functions, which can lead to cybersecurity vulnerabilities, false trips, or even equipment outages and costly shutdowns.
Internal clock: Siprotec 5 PTP Grandmaster Clocks
This risk is eliminated by Siemens' patent-pending technology.
The Siemens Siprotec 5 devices, designed for the control and monitoring of electrical systems, incorporate so-called "Precision Time Protocol (PTP) Grandmaster Clock (GMC)" clocks. These comply with the international standard that specifies the synchronization of network device clocks with an accuracy of less than one microsecond. In other words, they provide an extremely stable local time base.
The essence of the solution is that the devices use an internal oscillator as the primary time reference, thereby making themselves independent of external GNSS signals. The seamless "PTP grandmaster" switchover technology ensures that when the primary clocks (for example, the time server receiving the signal from the GPS receiver) return, they first synchronize with the active PTP Grandmaster Clock devices, and only then resume their original role.
As a result, disruptive time base jumps occurring during switchovers can be prevented, and protection functions remain continuously available. In other words, the system also becomes more resistant to cybersecurity vulnerabilities.