Universal GIS bypass solution for substations

A transportable universal cable system up to 132 kV has been developed for rapid use in the event of gas-insulated switchgear (GIS) failures in substations.

PFISTERER developed and supplied the system for the Spanish high-voltage grid operator Red Eléctrica de España (REE), in an EU-funded project. The turnkey, dry cable connection solutions enable bypasses in the event of a faulty GIS system as well as uninterrupted installation or maintenance of existing system components. In the final stage, the system will comprise around 30 shipping containers suitable for all existing installations and possible application scenarios on the island groups of the Canaries and Balearics.

Reliable operation of the electricity networks in the Canary Islands and Balearics is essential to supply electricity to the local population and tourist centres. At the same time, the isolated location of the islands is a particular logistical challenge in the event of system failures, explains PFISTERER. In addition, the energy infrastructure comprises numerous cable and connection systems by different manufacturers and REE therefore required a solution that is able to work for all types of transformers and GIS, regardless of the equipment’s original equipment manufacturer or the applicable standard. REE conducted a study that identified around 30 different application scenarios in total. They wanted a solution to ensure reliable grid operations that would be as universal and flexible as possible.

PFISTERER asserts that it was able to offer a solution that can be deployed rapidly in all application scenarios. To reduce complexity, all connections are based on pluggable, dry CONNEX cable connectors and dry terminations. As a result, only these components have to be kept on hand for bypass cable systems from GIS to GIS, or from GIS to air-insulated switchgear. The company then designed a seaworthy transportable container solution that is suitable for rapid deployment on the islands.

The first stage of the cable system comprises a total of 54 cable drums including EST SUB terminations with surge arrester and CONNEX plug connectors for 66 kV and 132 kV – securely stored ready for use in 18 seaworthy HQ 20’ containers. Each container holds everything necessary for a particular bypass scenario in the event of faulty gas-insulated switchgear in a substation, including three motorised cable drums with cable lengths of 50 m to 100 m in different configurations. The containers are stackable and can be transported by truck or ship – seaworthiness is important for maritime transportation between the islands. The motor-driven cable drums allow the cables to be unrolled at the place of use and can be wound back onto the drums to be used again. Motorised doors on both sides are designed to provide optimum access in the field. A mast and lifting equipment are built into the container to enable the installation of terminations on an overhead line. The solution with integrated surge arrester protects the cable and the fitting while facilitating fast installation, as the surge arrester is also used as the fixing point for the termination.