RISe to new horizons

A greener technology for a greener world

RIS bushings are a trailblazer for sustainable high voltage technology. Together with our capacitance graded cores, they form the technological basis of the future – already today. Dive in, discover how they work, and you'll get a whole new view of bushings.

Ready for the future? It's already here.

A superior bushing

Absolute reliability. Highly ecofriendly. Maximum efficiency. That’s what defines a superior bushing. We have made it possible. There are two factors that make our bushings stand out from the rest. Capacitance grading of the core to control the electrical field and the change from RIP technology to RIS technology in the insulation for more safety and sustainability. Let’s start by highlighting the functionality behind capacitance graded cores for bushings.

Here you can get an overall handout about the RIS-technoglogy.


Value condensed to the core

Capacitance grading to control the electrical field.

To enable a homogeneous electric field strength distribution, we constructed the core with several integrated conductive layers. This condenser core consists of epoxy resin, aluminum layers and synthetic fleece (Resin Impregnated Synthetic). N2 based foam serves as the secondary insulation between the core and the insulator. The whole design of the bushing is complete free of any oil and SF₆.

Fits perfectly. For all applications.

The upper half shows a bushing with a capacitive field control. The field lines are distributed uniformly in a homogeneous electric field with no local increase of the electrical field strength at any point. The lower half depicts a bushing with a geometrical field control. This results in an inhomogeneous electric field distribution with a clear critical point of electrical field strength.


Geometrical field control

  • inhomogeneous electric field distribution
  • critical point due to local high electric field

Capacitive field control

  • homogeneous electric field distribution
  • no local increase of electric field

Maximum potential by design

RIS bushings combine functionality and technical requirements

Our bushings are carefully designed to maximize their potential by incorporating various elements such as electrical field strength optimization, enhanced insulation, pollution protection, and structural support. These design features work together to optimize the performance, reliability, and lifespan of the bushing, ensuring safe and efficient operation in high voltage applications.

Sometimes, the choice is obvious.

Convincing beyond the standard.

RIS acts as innovative technology with key benefits and technical advantages that speak for themselves.

Vision creates change

Today, the stresses placed on high-voltage technology far exceed those of the past. Managing these increasing dynamics is a key component of future HSP applications. Aspects like SF₆-free insulation, high overload capacity, and compact design go hand in hand with increasing standardization. And thus support current global developments.

We know what’s gaining importance – so we

can develop tomorrow’s solutions today.

hsp_bernhard_heil_neu.jpg Dr. Bernhard Heil, Manager Research & Development

Safe when it counts.

RIS is our future technology – but already has a proven track of success. (reference date: 2022)

Furthermore, we regularly put RIS bushings under stress and do extensive tests to approve it for different mechanical and electrical loads.



Start of regular operation


2148 RIS bushings

in operation


50 million

operating hours



failure rate

Thermal cycle test with dynamic mechanical load and continuous electrical load

Approved in an external climate chamber at Karlsruhe Institute of Technology with thermal cycles in the range of -60 to 50°C in 5 cycles over 460 hours.

  • Applied voltage of 80% of Up
  • Applied dynamic load of 2500 N / 30.000 load cycles

Long term laboratory test comparing RIS and RIP

Comparative accelerated aging test of RIP and RIS condenser cores with DC stress applied.

  • No failure after triple test time of RIP break-down
  • DC lifetime of RIS significantly higher compared with RIP

More to come in the future

The potential of RIS technology is not yet exhausted. There are plenty of DC tests currently running to improve and expand our portfolio.

Prototype for RIS 111 kV HVDC bushing
  • Polarity reversal test: 90 min. neg, 90 min. pos., 45 min. neg.

  • DC applied voltage withstand test: 120 min. pos. polarity

  • DC long term test: 360 min. pos. polarity

    Successfully tested up to 200% of DC voltage

Prototype for RIS 545 kV HVDC bushing
  • TRT test with increased ambient temperature passed

  • Thermostability test

  • DC test with increased values

  • DC test in Ester-transformer oil

    Tests planned to be finished in 2023

Seismic performance

Seismic performance verified by calculation, static and dynamic load tests. Equal seismic performance compared to RIP products.

We're here to talk.

If you have any question about RIS technology or anything else just contact us.

Smaller footprint,
bigger impact

We mathematically compared the environmental footprints of RIS and RIP technology. The results were not only promising, but very clear!

Baseline scenario

  • 40 years in operation
  • Realistic temperature based on average load of 70%
  • The RIP values include a replacement after 30 years
  • RIS with expected minimum lifetime of 40 years


lower carbon footprint than RIP products


less energy losses than RIP products

Powered by people that
create high voltage technology.

The company

For decades, we have been driving innovation in the high-voltage sector. By promoting new perspectives, we remain at the cutting edge.


Research & Development

For HSP, each day is an investment in the future. Discover our Research & Development division and see how we shape tomorrow’s solutions – today.