V. S. Vysotsky, Dr. Sc. (Engineering), Superconducting Wire and Cable Division Manager, OJSC VNIIKP;
S.Yu. Zanegin, Senior Engineer, OJSC VNIIKP;
D.S. Kaverin, Cand. Sc. (Engineering), Senior Research Scientist, OJSC VNIIKP;
L.V. Potanina, Cand. Sc. (Engineering), Leading Research Scientist, OJSC VNIIKP;
S.M. Ryabov, Senior Engineer, OJSC VNIIKP;
Structural defects of superconducting Nb3Sn wires in the ITER conductor caused by electromagnetic loads
The acceptance parameter Tcs (current sharing temperature) decreases with increasing number of test cycles for toroidal field conductors of ITER magnet system manufactured in all countries except Russia were shown during final electromagnetic cycling. Russian conductors show not only the high stability of Tcs, but also its modest increase. Probable reasons of Tcs stability during electromagnetic cycling are the smaller damage of brittle Nb3Sn filaments in the Russian design of the superconducting strands, and the Russian performance of the conductor, which provides greater compaction level and, as a result, better mutual fixation of the strands. This article presents the results of a statistical metallographic study of superconducting filaments in Nb3Sn strands extracted from a conductor after electromagnetic cycling. The possible reasons of Tcs stability due to the manufacturing technology of the conductor are proved qualitative.
cable in conduit conductor; ITER; Nb3Sn; image analysis; metallography; current sharing temperature; statistical data analysis; superconducting strands; cable compaction.
A.Ya. Zagalskaya, Engineer, OJSC VNIIKP;
A.A. Kryuchkov, Cand. Sc. (Engineering), Leading Research Scientist, OJSC VNIIKP;
Т.A. Stepanova, Research Scientist, OJSC VNIIKP;
Thermomechanical analysis as a method for evaluating the degree of polyethylene crosslinking
The paper gives a brief review and analysis of the methods for evaluating the degree of polyethylene crosslinking that were described in appropriate literature. The weak points of these methods limiting their applicability in actual control of cable and wire quality are outlined. The advantages and potentialities of the thermomechanical analysis used for this purpose are demonstrated.
polyethylene; thermomechanical analysis; degree of crosslinking; thermal deformation; gel fraction.
A.V. Grin', Leading Design Engineer, "Estralin PS” Ltd.;
A.S. Mneka, Technical Director "Estralin PS” Ltd.;
Cable terminations on power transmission poles of 110-220 kV cable lines
In some cases during the installation of 110–220 kV overhead cable transmission lines it may be needed to terminate the cable lines comprised of XLPE cable directly on the power transmission poles.
With this arrangement there is no need to make intermediate bridges or transition points for the terminations and high-voltage surge suppressors located at the power transmission poles, which simplifies the construction of 110–220 kV overhead cable lines. The paper contains recommendations concerning the choice of cable terminations manufactured by various producers to be installed on power transmission poles (with the analysis of their advantages and drawbacks). Specific aspects of 110–220 kV cable shield grounding and optical fiber assembling (if cables have optical fibers under the sheath) are given, technologies of mounting cable terminations on power transmission poles that were used on various overhead cable lines are describedd.
110–220 kV overhead cable line; XLPE cable; 110–220 kV cable termination; power transmission pole.