Electrical Interview: FINDING OF TRANSMISSION LINE RATING

          When ever we see the transmission lines on road side,we will find the rating of transmission line very  easy.First we calculate how many insulators are used for that transmission lines.

                Number of insulator disks = operating voltage per phase/maximum voltage of each disk(11KV )

                      Operating voltage of line = number of insulator disks x maximum voltage of each disk(11kv)
         By using this formula we can find any transmission line rating.for example
                                 
                                                  LINE                   NUMBER OF DISKS
                                                   33   kv                          3  disks
                                                   132 kv                          8  disks
                                                   220 kv                        13  disks