Modernising Soviet Era Electricity Distribution Grids

Electrical switchgear engineers NOJA Power today announces the installation of two OSM Reclosers as part of a modernisation program for Soviet-era electricity distribution grids in the Baltic states.

FIMA designs intelligent engineering systems and tailor-made solutions for organisations across the Baltic region. The company’s energy division offers NOJA Power’s ACRs as part of its electricity substation upgrades, a retrofit program for Baltic distribution grids which has been in progress for several years.

So far, two OSM38 ACRs have been deployed and linked to a supervisory control and data acquisition (SCADA) system communicating with substations using the IEC 60870-5-101 [IEC101] transmission protocol. The ACRs protect the grid and help utility staff identify faults – improving reliability of supply and speeding up reconnection to consumers after failure.

Electricity distribution grids in the Baltic region comprise a mix of 10, 20, 35 and 40.5-kV systems. Before the modernisation program, protection was limited to older circuit breakers using mineral oil as the insulator for arc quenching between the contacts in the event of a fault. The circuit breakers are large and heavy compared with NOJA Power’s modern units, and the use of mineral oil introduces potential safety hazards in the event of an internal arc fault. In addition, the circuit breakers are relatively unreliable, environmentally unfriendly and don’t support the latest communication or power quality monitoring capabilities.

In contrast, the OSM38 ACR represents the most up-to-date distribution automation equipment available. The ACR provides a comprehensive suite of protection and automation features, voltage measurement on all six bushings, current measurement on all three phases, bidirectional protection and extensive power quality and data logging capability. In addition, OSM38 ACR benefits from the use of vacuum interrupters and solid dielectric insulation instead of the environmentally unfriendly oil or sulphur hexafluoride (SF6) gas used in older switches. Another key feature of the OSM series is its stainless steel enclosure that forms the only solid dielectric unit with controlled internal arc fault venting on the market.

The OSM38 ACR, originally type-tested to a maximum rated voltage of 38 kV, has now been retested at KEMA, an independent test laboratory in The Netherlands, up to a maximum rated voltage of 41 kV - enabling its deployment on all distribution grids in the Baltic region.

“The NOJA Power auto reclosers have proved popular with the utilities not only because they offer a leading technical solution, but also because the engineering support from the company is excellent and utility staff find the units simple to configure and operate,” says Valentas Titarenka, a Project Manager. “And now that the OSM38 ACR has been type-tested for 40.5 kV distribution grids, we expect to see much wider deployment across the Baltic states.”

“Building a smart grid isn’t always about just upgrading a reliable conventional grid by investing in some of the latest distribution automation such as NOJA Power’s auto reclosers,” explains Neil O’Sullivan, NOJA Power’s Group Managing Director, “often, as in the case of the Baltic states, building a smart grid requires a massive overhaul of decades-old infrastructure.

“The OSM series can make this job easier by offering a proven auto recloser and sectionaliser solution, installed in over 100 countries around the world, with the most up-to-date protection, monitoring, safety and environmental features combined with a user interface that makes configuration and operation straightforward.”