Exhibit 23(a) INDEPENDENT AUDITORS' CONSENT We consent to the incorporation by reference in Registration Statement Nos. 333-33284 and 333-00973 of Public Service Company of Oklahoma on Form S-3 of our reports dated February 22, 2002, appearing in and incorporated by reference in this Annual Report on Form 10-K of Public Service Company of Oklahoma for the year ended December 31, 2001. /s/ Deloitte & Touche LLP Deloitte & Touche LLP Columbus, Ohio March 28, 2002