TRANSFORMERS, SUBSTATIONS + CABLES
Resolving the ‘trouble’ with RTUs At utility substations, RemoteTerminal Units (RTUs) are critical components used for monitoring circuit breaker positions, alarms, voltage/current, temperatures, and additional data from various wired sensors.They can also control breakers, tap changers, and capacitor banks. However, for many utilities, RTUs remain a trouble spot. As RTUs age, reliability issues, unforgiving software, lack of vendor support for older product lines, increased training time, and diminishing availability of replacement parts can make RTUs an ongoing and time-consuming issue for substation technicians.
I n the USA, NovaTech Automation is assisting a major Midwest utility in its multi-year replacement of all remote terminal units at its substations. “I get more trouble calls related to RTUs than I should,” says the senior supervisor at a Fortune 500 electric and nat- ural gas utility that serves the power needs of seven states in the Midwest. “I need my RTUs to work reliably because my field engineering team doesn’t have the time to keep coming back to resolve trouble calls and investigate why an RTU is not functioning properly or has stopped working.” Despite using RTUs from several known providers, the reliability issues became so frequent that the engineering team decided the best course of action was to start up- grading all the RTUs across its entire network. “Some of our RTUs started having software and hard- ware failures,” says the senior supervisor. “They were not very old, maybe ten years. We had one unit where the screen froze, and the software and the configuration were corrupted. The RTU vendor told us the only thing we could do was to rebuild the database, which we did, completely.” While the engineering team had the knowledge and experience to resolve the issues, it was another task for already thin resources. The team at the utility already has extensive responsibilities that go beyond substation instal- lation to include programming and telecommunication sys- tems. “We manage more or less everything that goes from the main control centre to the handoff at the end device in the substation,” he adds. A further factor that contributed to the utility’s decision to replace its RTUs was the fact that another of its RTU vendors
When the Midwest utility found its legacy RTUs becoming unreliable and overly demanding on maintenance time, it turned to replacing all the units across its network. announced it would no longer support its existing software. This would require the utility to replace the software and re-train the team. “The training for the new software would have cost $30 000 for one week of in-person training,” says the senior supervisor. As a result, the team started to explore other options on the market. This led them to an RTU manufacturer that sold them on the promise of a newly redesigned platform. The vendor brought in a new RTU for an initial test. “It just didn’t work,” says the senior supervisor. “For an installation job that was supposed to take about two and a half hours, we ended up putting the old RTU back in place thirteen hours later because the vendor could not get the replacement unit running.” Adopting a higher level of scrutiny of the claims made by other RTU vendors, utility personnel then began discussions with Pennsylvania-based NovaTech Automation, a leading substation automation provider. The company proposed its OrionLX automation platform as an RTU replacement. The NovaTech OrionLX-based RTU, including the I/O system, the Alarm Tile Annunciator, Maths & Logic routines, and IED data access, is configured via the NovaTech Configuration Director (NCD), a licence- free tool used for Orion models. NCD eliminates most of the effort typically entailed in configuration by providing pre-configured pick lists for over 250 commonly applied intelligent electronic devices (IEDs). After testing the new RTU to validate its performance, the utility chose to replace its existing units with the NovaTech Orion line (LX, LX+, LXm, and now Orion I/O) together with the company’s Distributed Discrete I/O (DDIO) and
One of the engineers at work on the installation of new RTUs.
24 Electricity + Control MARCH 2022
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