Need of Transmission Line Protection


~A variety of equipment such as generator, transformer, switchgear,

~ CT, PT, over hade  transmission line, underground cable, control equipment etc. are used in power system.  

~This could lead to a fault in any equipment for any reason.  Therefore a protection system is required to protect the equipment when a fault occurs,

~Many long transmission lines are used in power systems.

~  This line is kept open so there is a high probability of fault due to whirlwind, storm, no, lightning and tree branches, water etc.

~  Also, dust etc. on the insulator causes flash over.  If we check the fault statistics, 50% of the total number of faults occurs in the fault overhead line.

                                       

      Percentage of fault to different different  Equipment


~ 50% fault in over hade line

~ 9% fault in under  ground fault

~ 12%  fault in CT,PT , Relay

~ 10% fault in Transformer

~ 8% fault in Generator

~ 8%  Line to Line Fault   

~ 85% Line to Ground fault

~ 5% Line to Line to Ground fault

~ 2% three phase fault 



                                                                Transmission Line