Section 5(7)(ii) in Tamil Nadu Electricity Grid Code, 2005
(ii)The above contingencies shall be considered assuming a pre contingency system depletion (Planned outage) of another 230 k V D/C line or 400 kV S/C line in another corridor and rot emanating from the same substation. All the Generating Units may operate within their reactive capability curves and the network voltage profile shall also be maintained within voltage limits specified.