String The type of EHV cable distribution asset category
Options: ehv_asset_category =
c("33kV UG Cable (Oil)", "33kV UG Cable (Gas)", "33kV UG Cable (Non Pressurised)",
"66kV UG Cable (Oil)", "66kV UG Cable (Gas)", "66kV UG Cable (Non Pressurised)",
"132kV UG Cable (Oil)", "132kV UG Cable (Gas)", "132kV UG Cable (Non Pressurised)")
.