Optimization of water terminations for testing of solid dielectric cable

Water test terminations for power cable are increasingly important with the increasing use of solid dielectric cable at AC and DC transmission voltages. The present contribution provides numerical solutions and analytical approximations for important parameters (temperature rise, field grading, etc.) for single water layer terminations for the cases of water flowing from bottom to top and from top to bottom. Analysis of these cases demonstrates that relatively uniform grading can never be achieved in a single water layer terminal when the water is flowing from bottom to top, but can be achieved readily when the water is flowing from top to bottom, as in the latter case, the effects of increased temperature as the water flows from top to bottom offset the effect of increased capacitive current coupled from the conductor, rather than exacerbate that effect as when the water flows from bottom to top.