Power tower is crucial to the power transmission

its safety and reliability is directly related to economic operation of the entire power grid system.However

power transmission tower is probably crushed

pulled

twisted and to be broken by the increasing stress of tower body as several of natural factors.A model of power tower is developed

two fiber Bragg gratings（ FBG） are mounted on the surface of the left plane truss of main beams of tower body and the other two FBG are mounted on the surface of the right plane truss of main beams of tower body

where the measuring points are respectively located at the position of 1 /2 length of four main beams of tower body.The deflections of main beams are induced by internal stress of loading

which cause the wavelength shift of FBG mounted on the surfaces of main beams.Loading experiment indicates that load sensitivities of four measuring gratings respectively are 5

6

7

6 pm /kg when the loading and unloading effects on main beams of tower body

the repeatability errors are 1.9 % FS

2.6 % FS

3.2 % FS

1.2 % FS.