The categorisation of grid incidents and grid disturbances shall be as follows:-
(1) Categorisation of grid incidents in increasing order of severity,- Category GI-1 - Tripping of one or more power system elements of the grid like a generator, transmission line, transformer, shunt reactor, series capacitor and Static VAR Compensator, which requires re-scheduling of generation or load, without total loss of supply at a sub-station or loss of integrity of the grid at 220 kV (132 kV in the case of North-Eastern Region);
Category GI-2 - Tripping of one or more power system elements of the grid like a generator, transmission line, transformer, shunt reactor, series capacitor and Static VAR Compensator, which requires re-scheduling of generation or load, without total loss of supply at a sub-station or loss of integrity of the grid at 400 kV and above (220 kV and above in the case of North-Eastern Region).
(2) Categorisation of grid disturbance in increasing order of severity,- Page 11 of 19 Category GD-1 - When less than ten per cent. of the antecedent generation or load in a regional grid is lost;
Category GD-2 - When ten per cent. to less than twenty percent of the antecedent generation or load in a regional grid is lost.
Category GD-3 - When twenty per cent. to less than thirty per cent. of the antecedent generation or load in a regional grid is lost;
Category GD-4 - When thirty per cent. to less than forty per cent. of the antecedent generation or load in a regional grid is lost ;
Category GD-5 - When forty per cent. or more of the antecedent generation or load in a regional grid is lost.
Explanation: For the purpose of categorisation of grid disturbances, percentage loss of generation or load, which ever is higher shall be considered.