** China Resources Power Holding drops 11.2% to HK$18.42, lowest since Sept. 16

** Stock top pct loser on Hang Seng Index and Hang Seng Composite Index

** Power plant operator planning to raise HK$3.89 bln ($500.5 mln) via placement of 198.5 mln shares at HK$19.70 - a 5.1% discount to last close - to repay debt among other things

** In separate deal, co will issue 168.1 mln shares to its controlling shareholder China Resources (Holdings) under a subscription agreement for HK$3.31 bln

** Hang Seng Commerce and Industry Index gains 1.3%,

Hang Seng Composite Index and Hang Seng Index up 1% each

** Stock adds 23.8% YTD

($1 = HK$7.7727)

(Reporting by Donny Kwok)

((donny.kwok@thomsonreuters.com))