SAN FRANCISCO (Standard&Poor's) Feb. 24, 2012--On Feb. 24, 2012, Standard&Poor's Ratings Services changed its short-term rating on Tucson Electric Power Co. to 'B' from 'B-2' following a revision of our short-term rating definition for the 'B' category and removal of the 'B-1', 'B-2', and 'B-3' rating definitions. RELATED CRITERIA AND RESEARCH Standard&Poor's Ratings Definitions, Feb. 24 2012