NEW YORK (Standard&Poor's CreditWire) March 19, 1999--Standard&Poor's today upgraded the senior unsecured debt of Duke Energy Corp. to single-'A'-plus from single-'A'. Other ratings on Duke Energy and its affiliates (see list below) were affirmed. The outlook remains stable, except for Panhandle Eastern Pipe Line Co., which remains on CreditWatch with negative implications pending its sale to CMS Energy Corp., and Duke Energy Trading and Marketing LLC, which remains on CreditWatch with positive implications pending the merger of Mobil Corp. and Exxon Corp. The rating revision reflects the expectation that after the imminent refinancing of $650 million of first mortgage bonds, recovery prospects for Duke Energy's unsecured debt will no longer be materially disadvantaged by the presence