Spacer Damper Fatigue Testing

Advanced Life Cycle Fatigue Rig for Tyco Electronics

Author

Paul Riley is the MD and software engineer of Computer Controlled Solutions Limited (CCS) and has been alliance member with National Instruments since 1994. He has an extensive physics/electronics/computing background applied to test and production machine control and data acquisition.

Products Used

The following Compact RIO Hardware

• PCI 7813R
• 4 Slot Expansion Chassis
• cRIO NI9237
• cRIO NI9263
• cRIO NI9421
• cRIO NI9472

USB Hardware

• NI-USB-6225M

Software:

• LabView 8.5.1 Professional
• LabView FPGA 8.5.1
• cRIO 2.4.1

Industry

Overhead Power Transmission Lines

Challenge

To provide the following:

1. A highly reliable test rig for Lifecycle testing of a new generation of spacer dampers for use on overhead power transmission lines
2. An accurate 4 channel load and angle control test system
3. Reliable control and monitoring over 20 Million cycles
4. Dynamic control of CAM like operations on-the-fly.

Solution

The solution was to use National Instruments FPGA based hardware with CCS software design to provide 4 totally independent cycling rigs under the control on a single PC. Very high speed PID control coupled to advanced linear motors ensured accurate control, long life and accurate fault monitoring.

Body

Tyco Electronics UK provide hardware for the overhead line industry.  Overhead power cables have their separation maintained using an assortment of dual, triple and quad spacer dampers. These dampers protect the cables from wear and premature fatigue failures, maintaining electrical and mechanical performance during onerous climatic extremes and system faults.

The new generation of quad and triple spacer dampers are undergoing development by Tyco Electronics and will form part of a long-term programme to upgrade the UK power transmission network over the next decade. Key to the service requirement is the ability to offer an operating life of at least 25 years, without maintenance or loss of performance. Life cycle testing is therefore a crucial part of this testing. A defined set of tests have to be followed involving the oscillation of the damper arms at known frequencies, forces and angular displacements. Historically this testing has been carried out by oscillating the damper arms using an AC motor on a CAM arrangement.

Computer Controlled Solutions Ltd provided a more advanced solution with the use of National Instruments software and hardware plus linear motors from Parker SSD. By combining the FPGA technology with a linear drive system we could accurately control, monitor and acquire data on four independent test rigs. In addition, without the CAM type system the amplitude of oscillations could easily be controlled without stopping to alter the CAM radius.