Renewal 220kV Substation Fällanden

‍Project Description:

‍The existing 220 kV outdoor switchgear at the Fällanden substation has reached the end of its technical service life. Therefore, the substation is to be renewed and modernized to ensure the long-term efficiency and safety of the region's power supply. As part of the renewal, a new gas-insulated 220 kV switchgear (GIS) will be built, gradually replacing the existing outdoor switchgear (AIS). Additionally, the substation will be expanded with the construction of a modern, two-story building to accommodate the increased space requirements for the new technology.

Construction and Technical Details:

New GIS Building:

‍The new building for the gas-insulated 220 kV switchgear will be constructed as a two-story structure with an optimized space concept, including a compact cable basement. The room layout has been adapted to the site conditions, as the available space is limited. During the construction phase, a temporary access road will be used. After project completion, a separate access road to the substation will be established.

Primary Technology:‍

The existing outdoor switchgear (AIS) will be replaced by the new gas-insulated switchgear (GIS), which is based on state-of-the-art technology. The connection of the four transformers (2x 220/150 kV and 2x 220/110 kV) will be implemented via new 220 kV cable routes and overhead line crossings. These new connections will ensure a secure and efficient power distribution between different grid operators.

Secondary Technology:

All secondary technology will be housed in the new building and implemented according to the latest technical standards. This includes the interfaces to the four transformers, which will be newly configured according to the most recent standards. The transformer protection and control systems will also be replaced as part of the project. Adjustments and temporary installations in the secondary technology sector will be made to ensure a smooth transition from the old to the new infrastructure.

Auxiliary Power and Emergency Power Supply:
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The substation's auxiliary power supply will be implemented according to the latest standards. Additionally, an emergency diesel generator will be installed to be prepared for all eventualities and ensure power supply reliability even in the event of outages.

Overhead Line Integration:

A key component of the project is the integration of overhead lines that connect the Fällanden substation with neighboring grid facilities. The existing overhead lines will be expanded with new lines and switching configurations as part of the modernization to ensure future grid stability and security:

• Benken East – Fällanden: The overhead line connection will be integrated into the GIS system via a new 220 kV cable route.
• Benken West – Fällanden: This overhead line connection will also be integrated into the GIS system via a new 220 kV cable route.
• Auwiesen East – Fällanden: A new overhead line crossing will be built for this connection, with tensioning at the new overhead line portal for direct integration into the GIS system.
• Grynau – Fällanden: The Grynau overhead line will be connected to the GIS system via a new overhead line crossing at the new overhead line portal.
• Breite – Fällanden: The Breite overhead line will also be connected to the GIS system via a new overhead line crossing at the new overhead line portal.

The modifications and new constructions of the overhead line connections are crucial for integrating existing and new lines into the GIS system, ensuring that various power sources are efficiently and securely interconnected.

Conclusion:

This project represents an important step in modernizing the infrastructure and ensuring a long-term, secure, and efficient power supply in the grid area of Zurich North. Through the construction of the 220 kV switchgear, the improvement of primary and secondary technology, and the expansion of emergency power supply, the substation will be prepared for the future demands of energy supply. The integration and modernization of overhead lines are also key components to maintaining a stable and secure grid connection.

The collaboration between grid partners, along with detailed planning and execution, ensures high-quality and reliable infrastructure.

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In this project, FGS, on behalf of Axpo Grid AG, is responsible for overall project management, coordination, and support of the primary technology, overhead line, auxiliary power, and construction work, as well as coordinating sub-planner services.

For further questions or more detailed information, the FGS team is happy to assist.