NES disposes of a comprehensive test laboratory equipped with test machines and apparatus designed to perform mechanical, electrical, thermal and dynamic tests on the whole range of transmission line fittings. It is extensively used for research and development on new products, for quality control of incoming materials, for routine tests on semi-finished items and for type and acceptance tests of finished products. For example, three tensile machines (two verticals and one horizontal) are used for mechanical tests up to 1200kN.
A computer controlled test machine have been developed to perform heat cycle tests on tension clamps and joints by means of an high current power supply system able to produce up to 5000 A. This test equipment is used to carry out type test for tension clamps and joints for standard conductors and for high temperature low sag conductors with INVAR core.
Particular attention is given to the vibration test equipment composed by a shaker and a 45m test span fully instrumented. The vibration test equipment is totally controlled with a software developed to perform automatically all the vibration tests required by the national and international Standards and also special tests included in the Client’s specifications, such as:
- Dynamic response curves of Stockbridge type vibration dampers, at constant velocity or constant displacement. The results are tabulated and plotted in curves showing force, phase, impedance and power versus frequency in a frequency range of 3÷150 Hz.
- Effectiveness tests of vibration dampers installed on the test span, in accordance with IEC and CIGRE recommendations.
- Elastic and damping characteristics of spacer-dampers with plotting of hysteresis cycle
- Fatigue test on vibration damper, flexible spacers, spacer dampers and OPGW.
- Self damping measurement on any conductor/cable tensioned on the test span, including measurements of Power/energy dissipation, antinode amplitude and bending strain along the span and at the extremity.
- Comparison between results obtained with and without dampers, as well as, with and without armour rods.
The laboratory is continuously updated and upgraded through the design and installation of new test stands and apparatus, that are, as far as possible, computerized for the automatic execution of the tests and for the data reduction, elaboration and presentation.