Structural and mechanical design of gas-insulated switchgear
This example illustrates the cost-effective design of a gas-insulated switchgear (GIS) and the associated supports from a static mechanical point of view. International system projects are planned, calculated, controlled, supported, and monitored while taking into account customer specifications, general standards (e.g. for loading ratio) and special standards (e.g. for aseismic design).
Range of workThe work ranges from smaller systems mainly used inside buildings to large, extensive systems designed as nodes and connections to overhead power lines.
First stage: calculation
In the first stage, the entire system is modelled, calculated, and optimized – including supports and specific loads – using computer-aided calculation programs. Next, the exact position of the loading points is defined and the foundation load data generated. Based on the foundation load data and constructional data including the loading points (with buildings and exteriors, if applicable), it is now possible to dimension the building, foundation, and fixing points.
Second stage: documentation
In the second stage, the design documentation and detailed engineering of the supports are generated. A subcontractor assists in the creation of the framework statics and, finally, the shop/assembly drawings for the individual frameworks.
It is then possible to coordinate and implement production, transport and, of course, assembly.
Additional focus areas
- Detect and evaluate project-related risks and, if applicable, develop recommendations to minimize risk and to recognize and exploit opportunities.
- Support installation departments in solving unexpected problems related to the installation, commissioning, and functionality of the GIS.
- Technical consultation with customers, suppliers, and partners.
- Interdisciplinary and interdepartmental cooperation/coordination with primary departments, project management, sales, installation, the Berlin switchgear factory, subcontractors, and customers.
To take optimal advantage of the load carrying capacity of individual GIS components, predestined components are evaluated by means of a FEM calculation. A model of the component is imported into the program and supplied with the project-specific load spectra. The specialists then generate the FE mesh and assess the component’s load carrying capacity. At this point it is also possible to simulate various component loads in the actual experiment, thus also ensuring constant improvement in calculation methods and, consequently, guaranteeing cost-effectiveness.
To improve the calculation method and comply with various seismic standards, appropriate tests are conducted to determine earthquake resistance. For this purpose, components and even entire switchgear panels are vibrated on a “vibrating table” and subjected to various frequency spectra. Their seismic safety is tested and evaluated using strain gauges, displacement transducers, and other methods of analysis. Finally, the compulsory reconciliation is made between the experiment and method of calculation.