Sealing a GIS in Croatia

“As a design engineer I find Roxtec products really useful and user-friendly," says Mr. Radosevic, lead designer on TS Stenjevec and co-owner of Ravel design company. "Specific seals are very easy to find and to specify."

He stresses the role of the Roxtec team in Croatia during the design process of SS 110/20 kV Stenjevec.

"They helped us a great deal during the design process and made it possible to have all the design on time with their quick reactions to the problems we encountered during the design phase and also during the building phase.”

The design engineers of design firm Ravel specified Roxtec cable and pipe seals for the construction of the 110 kV gas insulated substation, and the electricians of contractor KONČAR performed the installations. All went very well, and Roxtec cable entry seals were successfully used for outer and inner walls as well as for openings for power, signal and control cables below the substation.

Mitigating VFTO

For the signal and control cables under the GIS, the design engineers specified Roxtec ES sealing modules for electromagnetic shielding and protection against EMI, electromagnetic interferences, and EMP, electromagnetic pulses. Thereby, the seals became part of the substation’s grounding system for mitigation of VFTO, very fast transient overvoltage.

Roxtec knock-out sleeves were used to pre-seal PVC pipes to keep the site dry until cable routing.

Meeting all requirements

They also specified Roxtec SLFOH plates under the GIS to cover multiple sealing demands. This ensured protection against fire, water and possible leakage of SF6 gas. It also added a robustness against cable pull-out forces which, in turn, enabled the contractors to use fewer clamps on the cable ladders. The Roxtec sealing system is available in versions for ensuring watertightness after fire. Another benefit is that the plates are openable to allow for additional cables, for example for expansion of the substation or if there is a malfunction and there is a need for flexible connection.  

Securing safe operations

Roxtec provided design support, installation training, and fast deliveries throughout the project. The owner, HOPS, can rely on the passive protection system. With full control and better bonding and grounding, they avoid damage or disturbance to equipment due to water ingress, humidity, rodents, VFTO or partial discharge activity. The GIS is built to operate without any crew and to be controlled remotely. It is therefore crucial with passive protection systems for secure and reliable operation.  

Why use Roxtec?

• Multi-hazard protection
• Design support
• Good references
• Installation training onsite
• Spare capacity for future expansion