Forward Thinking UK Power Networks Expands Digital Wide Area Restoration Abilities

Our partnership with UK Power Networks is marked by firsts. In 2015, the U.K.’s largest power distribution company was first to implement GE’s Automated Power Restoration System (APRS) on a live system. In 2018, UK Power Networks again took a standard-bearer’s role by implementing a customized Wide Area Restoration solution. Today, we’re in the second stage of developing an advanced version of our automation tool. UK Power Networks has been named as the world’s leading utility in Smart Grids by an independent global benchmark. This blog examines all that UK Power Networks and GE Digital have achieved with digital restoration capabilities.

UK Power Networks’ first forward-thinking step was to implement the APRS to improve its operational performance and asset utilization capabilities by leveraging big data to drive operational efficiency. Integrated with the Fault Location, Isolation, and Service Restoration (FLISR ) application, this technology helped improve UK Power Networks’ performance in critical regulatory KPIs such as Customer Interruptions (CI) and Customer Minutes Lost (CML)

After a few years of process improvements with the initial technology, UK Power Networks partnered again with GE Digital to extend the functionality of the APRS. The goal? To isolate and restore power to primary outages and integrate further with FLISR to restore even more customers, more quickly.

A primary outage, after all, may happen less often, but a lot of customers lose supplies when it does. As we discussed in a recent webinar, UK Power Networks wanted to improve KPIs such as Customer Average Interruption Duration Index (CAIDI) and Customer Average Interruption Frequency Index (CAIFI).

In the initial phase of the implementation, the goal was to enhance the existing automation and FLISR programs to react more quickly. PORT Lite was introduced at UK Power Networks in 2018. This interim solution proved successful, with over 190 successful operations of the PORT Lite restoring customers.

Since this first stage was focused on quick wins, GE Digital and UK Power Networks kept the logic straightforward. PORT Lite restores only a single primary at a time, for instance. Yet the solution enabled faster control processing of back feeds and improved insight into grid status for better decision making.

Next, the challenge was to train an autonomous algorithm for restoration. This required:

• Analysis of previous outages and how they were restored
• Review of safety rules around switching
• Extensive scenario analysis to determine expected responses

The team developing, reviewing, and testing the solution had a large number of remote terminal units (RTUs) available and had to identify factors such as types of equipment and alarm states upon which to base the algorithm’s decision-making. To date, UK Power Networks has 35,000 secondary and 1,500 primary RTU commissioned on the network which integrate with the centralized restoration systems developed with GE Digital.

Since PORT relies on fast connectivity model traces, this more in-depth stage of development also required setting up consistent classes across all UK Power Networks’ primary sites. The team had to work to make sure it understood all of the possibilities. This included establishing, say, if auto-reclose processing (ARP) was in cycle or not, or how to know a busbar state was dead.

As PORT is more advanced, it is able to trace up to the 33kV Grid infeeds which can inform decision making allowing for larger, safer and faster restorations. This means the automation algorithm can deploy to more complex sites with different configurations.

PORT can even handle multi-site losses. If Extra High Voltage (EHV) interrupts multiple primaries, PORT merges instances into a single program and back feeds sites from healthy donors.

The technology also traces upstream and downstream, monitoring multiple triggers and running safety checks such as:

• Person on site
• Busbar protection
• Fire protection
• Circuit breaker fail
• High-high current alarms and fault passage indictators on feeder

The restoration software also prioritizes local supply, then looks at customer numbers to get the best and biggest restoration it can. Since its deployment in 2020, it has restored the power of 72,000 customers in under 3 minutes.

PORT’s multi-layered restoration engine is an advanced control and optimization solution. Once it’s triggered, PORT traces the network to determine what is dead and what is healthy and goes feeder by feeder to restore load. The algorithm also identifies all feeders that can be restored at the same time (where donor load will not affect each other). Then, as each feeder is restored and load is adjusted in SCADA, it identifies new feeders without dependency. It doesn’t stop working until all customers are restored or there is no spare capacity left.

With PORT orchestrating the restoration, UK Power Networks is seeing business benefits such as fewer calls in from customers and saving control engineers from having to switch supply so that everyone can focus on repair.

Plus, the algorithm can also be advantageous in planning mode. UK Power Networks is able to explore “what if” and “where are faults likely” to do contingency planning and identify key replacement projects.

Ultimately, the GE Digital and UK Power Networks partnership discussed in our webinar demonstrates Wide Area Restoration handling one or more primary substations in a safe and controlled manner. The software decreases restoration time from typically up to 30 minutes down to less than three minutes, while minimizing impact and reducing customer interruptions and minutes lost.

Learn more about the Wide Area Restoration features available with GE Digital. Find out how this intelligent software manages outages at primary and 33kV voltage level, locates and isolates faults, allows back feeding from adjacent substations, and integrates with FLSR for the efficient feeder restoration a utility needs.