At the Transform congress, Pfisterer showcased its plug-in Connex system, a connection solution for installing compact power transformers. These space-saving connectors can be stored in much smaller spacers or even inside buildings. The plug-in high- and mid-voltage connections also allow transformers to be replaced in a very short space of time and remain flexible – even as network infrastructures start to change.
A gentle hum that fills the air, transformers spread across an area as large as a soccer field – that was the typical image of a substation until recently. However, this is due to change in future. Substations with a higher output spread over a third of the space or hidden away inside buildings – that is the future. “The trend towards urbanization requires a shift in the technical philosophy for substations: Moving away from classic overhead technology and moving towards insulated lines and touch-proof connection systems in enclosures” explains Eduardo Santana, Director of the Cable Systems Business Unit at Pfisterer. “This gives us the chance to build significantly more compact transformers.” The amount of building space is shrinking in highly-populated areas. As a result, substations need to generate more power across a smaller area or be incorporated into buildings, above or underground, or over several levels. These criteria cannot be met with conventional overhead line technology. Air-insulated lines need to be kept at safe distances away from other systems and components. This is why Pfisterer enhanced its space-saving, plug-in Connex system, originally designed as a cable connection for voltage ranges from 12 kV to 550 kV, turning it into a comprehensive connection system for transformers with highly compact mid-voltage connections and surge arresters with solid insulation for high voltages. Since all components are safe to touch, they can be easily and safely erected and inspected in even the most confined spaces without any need for protective barriers. Compared to components that are permanently installed, the plug-in connections offer unparalleled versatility when it comes to adapting to changing network infrastructures and minimizing maintenance and replacement costs.
Flexible for changing networks
Transformers with an estimated service life of up to 50 years are long-term investments. At the moment, it is impossible to accurately predict how network infrastructures and the deployment conditions of transformers will change and evolve over time. It is for this reason that the latest Connex system developed for transformers has been augmented by a new plug-in bushing for overhead connections. With Connex, power systems have a pluggable universal interface that is compatible with both overhead installations and insulated cables, thereby also safeguarding long-term operation of the systems when practical conditions change.
The universally pluggable Connex interface also reduces installation times by up to 75 percent compared to transformers with fixed plug-in bushings. Transformers and their integrated terminals form a single unit and do not need to be opened for on-site inspections or for connecting to the power grid. The fact that oil servicing is also not required further speeds up initial installation, maintenance and replacement. Delivered ready to use, oil-filled transformers can likewise be employed as mobile transformer units to eliminate the high costs associated with maintaining redundant, permanently installed backup or replacement transformers.
“Here at Pfisterer, we recognized the future demand for versatile transformers with compact connection systems a long time ago and responded by providing appropriate technical solutions”, explains Eduardo Santana. “Today a number of compact substations have already been installed in buildings, such as the new three-story underground substation in the Oerlikon district of Zurich – and the market continues to grow.”