Electrical substations are some of the most important facilities to protect during an earthquake. The equipment within these stations and transmission yards are essential to providing power to millions of homes, as well as to important public institutions like the police, fire department, hospitals and other first responders.

Unfortunately, electrical substations are vulnerable to seismic activity. At the same time, they can be very expensive and difficult to repair if affected. If an earthquake does damage a substation, the duration of downtown will likely be much longer than what we experience when our neighborhood lines go down.

The Solution—Ringfeder Friction Springs

To prevent seismic damage to electrical substations and switchgears, we’ve developed a special type of damper called the Friction Spring. In terms of its design, each spring consists of outer and inner rings with conical contact surfaces. When the spring column is axially loaded, the tapered surfaces overlap, causing the outer rings to expand and the inner rings to shrink in diameter.

Thanks to this design, the tapered surfaces of the mating rings will dissipate up to two-thirds of any introduced energy as friction.

Suitable For New Installations and Retrofits

We have one friction spring damper design that is used for base isolation of electrical substations for new or retrofit applications. The damper is assembled on top of the base plate of the electrical equipment—such as a CVT or switchgear—and will lift the equipment about half an inch off the ground during installation. No cranes or lifting equipment is required—only hand tools. The electrical equipment “floats” on the damper, even though the damper is positioned over the base.

In the picture below, you can see two spacers under the base (for illustration purposes only), verifying that the base is off the ground:

This next picture demonstrates how all the CVTs are connected by wires, making it difficult to lift without disconnecting the entire grid. Lifting the equipment half an inch to install our dampers during a retrofit is a simple solution.

Here are some of other benefits of our Friction Springs:

  • Reusable. Units are maintenance-free and can be reused after seismic events.
  • Fast. They react faster to applied forces than any other spring type.
  • Compact. Each Friction Spring gives you the highest forces for a given diameter.
  • Durable. Units are made of special spring-steel and coated with grease, enabling them to endure fire and high temperatures.
  • Customizable. When it comes to the return forces, we can change the grease, increase the outside diameter or change the taper angle to give you the results you need. And if you need less damping, we can also easily customize your spring.

To learn more about our Friction Springs, please visit our webpage.

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