Digital substation-roadmap for practical implementation

Voltage (HV) network. This demands significant grid investments, alongside reliable and costeffective power distribution with advanced automation.

Substation digitalization is central to achieving these goals. Helen began substation automation in the 1990s, adopted IEC 61850 station bus in 2007, and since 2018 has operated fully digital

Medium Voltage (MV) pilot substations using IEC 61850 process bus and Low Power

Instrument Transformers (LPITs) in Kalasatama. Eight years of experience confirm that full digital substations are technically and economically viable. LPIT technology, supported by IEC 61869 standard, improves feasibility and drives adoption.

Digital substations are now Helen’s preferred choice for greenfield projects starting in late 2024. A major HV/MV project in Pitäjänmäki demonstrates this approach, featuring HV Gas Insulated Switchgear (GIS) with LPITs, IEC 61850 process bus, and redundancy protocols. MV switchgear also uses LPIT technology and IEC 61850 process bus. While turnkey projects challenge service providers’ competence, risks related to technology maturity and reliability are being addressed.

The next step of Helen’s roadmap includes centralized and virtualized substation automation.

Centralization consolidates protection and control into fewer devices, while virtualization enables multiple applications on shared hardware, reducing costs and improving flexibility.

These innovations promise savings in investment and maintenance, though reliability risks must be managed. MV substations will lead implementation, before HV level projects. Possible centralised automation project for Myllypuro substation is analysed in the paper.

By leveraging LPIT technology, IEC standards, and virtualization, Helen aims to build a resilient, efficient network that supports the green energy transition and future demands of

Helsinki and Finland. This new technology also helps significantly to adopt the growing presence and effect of unconventional sources (solar and wind power, batteries etc.)