Power utility timing distribution is no longer accurate or resilient enough for modern requirements. New sources of energy like wind farms and private solar arrays now augment legacy power grids and as a result, traditional, one-way distribution networks are not enough to ensure accurate monitoring and synchronization for all of this new infrastructure.
The solution is for power grid operators to turn substations into monitoring and control points, and they have to integrate active sites into the wider operational control system. To do this in a way that satisfies modern synchronization standards, they must seamlessly integrate a range of superior technologies into current systems.
How substation sync works
Substations use dedicated protocols like IRIG-B and pulse per second (PPS) to distribute timing information to intelligent electronic devices (IEDs) in the network. Migration to Ethernet in recent years means Network Time Protocol (NTP) is also helping to support substation timing distribution as it combines high accuracy with improved availability. For these integrated NTP solutions, GNSS is very often used as the master time reference for the delivery of millisecond precision to IEDs.
That’s a good thing because timing sourced from GNSS is incredibly accurate. However, there’s a downside. GNSS signals are vulnerable to attacks like jamming and spoofing and not only are these increasing in frequency, they are also becoming more sophisticated – harder to detect and more difficult to fend off. When you’re dealing with critical infrastructure like power grids, countering vulnerabilities such as attacks on GNSS has to be at the top of your list of priorities.
So security is a major issue for legacy power grids, but there’s also another big challenge here – accuracy. Currently applied synchronization solutions are just not capable of meeting the synchronization demands of tomorrow. Ensuring enhanced availability is a key element of compliance with newer IEEE and IEC standards for smart grids, and there has to be a step-change for accuracy too - precision has to be fine-tuned from milliseconds to just microseconds.
The substation of tomorrow
To achieve those higher levels of accuracy and deal with threats to GNSS at the same time, you need a solution that augments and improves NTP. You get that by converging Precision Time Protocol (PTP) with NTP and IRIG-B. It’s a single solution that assures business continuity (because sync quality can be properly monitored) and it also gives extremely accurate frequency and phase synchronization, essential for IEC 61850 substation automation and IEEE C37.118 synchrophasor measurements.
For enhanced holdover capabilities, PTP grandmasters are equipped with high-quality oscillators to provide a local back-up. What’s more, network-delivered PTP timing is helping operators to counter the threat of outages caused by malicious attacks. With or without GNSS signals, converged PTP solutions ensure network timing never skips a beat.
With or without GNSS signals, converged PTP solutions ensure network timing never skips a beat.
The PTP set-up
Future-proofing smart grids with PTP timing begins with a local GNSS-disciplined oscillator as the source of legacy NTP and IRIG-B timing. If this device also supports PTP, a network-based backup for terrestrial delivery of highly precise frequency, phase, and time synchronization can be added. Such a multi-technology PTP grandmaster is synchronized by satellites but also with PTP from a central core clock and this provides security and vulnerability mitigation because the core clock always gives highly accurate frequency and time information, regardless of whether there’s a GNSS signal.
This end-to-end solution builds on physical hardware timestamping to both minimize delay and achieve the required levels of accuracy for synchronizing substations.
A seamless introduction of PTP timing
At ADVA, our Oscilloquartz team of timing experts has optimized our range of PTP sync devices for the specific needs of the smart grid. We’ve built a range of compact grandmasters that combine NTP, PTP, SyncE, and IRIG-B interfaces with multi-band GNSS receivers to make the migration of legacy synchronization cost-effective and completely seamless.
Another innovation, Syncjack™ technology, allows for continuous monitoring, testing, and assurance of timing accuracy. Our Ensemble Sync Director provides simplified management and assurance for the mitigation of GNSS threats and supports multi-vendor management. In combination with AI-assisted analytics, problems in the synchronization network as well as GNSS attacks are detected long before services are affected.
So by deploying ADVA solutions – and remember, these are specifically optimized to meet the exact requirements and regulations of the smart grid – operators can get the accuracy they need (one microsecond) and, for highest reliability, they have the option to combine an atomic cesium clock with an edge or core grandmaster for the highest precision and holdover possible. We’ve built a system that increases transparency, protection against GNSS vulnerability, and that satisfies new standards.
Making smart grids smarter
Smart grids are at a pivot point because they are having to undergo significant upgrades to comply with new standards. We’re also seeing this in mobile communications with the evolution towards 5G – operators are under massive pressure to deploy solutions that deliver faster, better, more secure services.
We think the only sensible way forward is to offer synchronization solutions that are specific to use case, backward compatible and yet future-proof. We’re offering a seamless migration to newer standards and we’re saving our customers a lot of cost and pain in the process.