| Power plant type 1 | Power plant type 2 | Power plant type 3 | …….. |
Power plant type 1 | 1 | a | b | c |
Power plant type 2 | 1\a | 1 | d | e |
Power plant type 3 | 1\b | 1\d | 1 | f |
… | 1\c | 1\e | 1\f | 1 |