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.
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.
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
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
DC test with increased values
DC test in Ester-transformer oil
Tests planned to be finished in 2023
Seismic performance verified by calculation, static and dynamic load tests. Equal seismic performance compared to RIP products.
We mathematically compared the environmental footprints of RIS and RIP technology. The results were not only promising, but very clear!
- 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