Method and apparatus for reducing wind induced vibration damage to electrical power line towers

A method for retrofitting an electrical power line tower comprising vertically spaced apart conductor supporting cross arms extending from at least one side of the tower and at least one shield wire supporting cross arm extending from said tower above the uppermost conductor supporting cross arm, each said cross arm having a mounting bracket welded to the tower end of said arm, said mounting bracket being attached to the tower via bolts for supporting said arm on said tower, each said cross arm supporting a high voltage electrical conductor or a shield wire near its free end, said method retrofitting said tower against wind induced vibration damage to said mounting bracket welds, comprising:

• a) affixing first clamping brackets to each conductor and shield wire supporting arm between the tower and conductor or shield wire and closer to the conductor or shield wire, said first clamping brackets including means to prevent their sliding along said arms and being selected to closely conform to the cross-section of the arm to which they are affixed, each said first clamping bracket comprising two similarly configured halves, each half having an interior surface conformed to one half of the cross-sectional shape of the arm to which it is to be mounted, the bracket halves being configured and dimensioned such that, when placed on said arm in facing relationship, their interior surfaces conform to the cross-sectional shape of the arm;
• b) mounting length adjustable bracing poles extending diagonally upwardly between said first clamping brackets on each conductor supporting arm and a bolt securing the mounting bracket of the next higher arm along said tower, said bracing poles which extend upwardly to a bolt securing the mounting bracket on a conductor supporting arm being formed of non-conductive material to prevent arcing from adjacent conductors;
• c) affixing a second clamping bracket to said bracing pole extending between said uppermost conductor support arm and a bolt securing the shield wire supporting arm mounting bracket to said tower;
• d) mounting a rigid support strut extending diagonally downwardly between said first clamping bracket on said shield wire supporting arm and said second clamping bracket for providing bracing support to said shield wire supporting arm;
• e) adjusting the length of said bracing poles for providing the desired bracing support to the conductor supporting arms to which said bracing poles are attached;
• and
• f) mounting vibration dampers to at least some of the conductor supporting arms on said tower.

An electrical power line tower comprising vertically spaced apart conductor supporting cross arms extending from at least one side of the tower, each said cross arm having a mounting bracket welded to the tower end of said arm, said mounting bracket being attached to the tower via bolts for supporting said arm on said tower, each said cross arm supporting a high voltage electrical conductor near its free end, the tower being resistant to wind induced vibration damage to said mounting bracket welds, comprising:

• a) a first clamping bracket on at least one conductor supporting arm positioned between the tower and conductor and closer to the conductor, said first clamping brackets including means to prevent its sliding along said at least one arm;
• b) a length-adjustable bracing pole extending diagonally upwardly between said first clamping bracket on said at least one conductor supporting arm and a bolt securing the mounting bracket of the next higher arm along said tower;
• and
• c) means for adjusting the length of said bracing pole mounted intermediate its ends, whereby the length of said bracing pole may be adjusted for providing the desired bracing support to the at least one conductor supporting arm to which said bracing pole is attached.

An electrical power line tower comprising vertically spaced apart conductor supporting cross arms extending from at least one side of the tower and at least one shield wire supporting cross arm extending from said tower above the uppermost conductor supporting cross arm, each said cross arm having a mounting bracket welded to the tower end of said arm, said mounting bracket being attached to the tower via bolts for supporting said arm on said tower, each said cross arm supporting a high voltage electrical conductor or a shield wire near its free end, said tower being resistant to wind induced vibration damage to said mounting bracket welds, comprising:

• a) first clamping brackets on each conductor and shield wire supporting arm positioned between the tower and conductor or shield wire and closer to the conductor or shield wire, said first clamping brackets including means to prevent their sliding along said arms and closely conforming to the cross-section of the arm to which they are affixed, each said bracket comprising two similarly configured halves, each half having an interior surface conformed to one half of the cross-sectional shape of the arm to which it is to be mounted, the bracket halves being configured and dimensioned such that, when placed on said arm in facing relationship, their interior surfaces conform to the cross-sectional shape of the arm;
• b) length-adjustable bracing poles extending diagonally upwardly between said first clamping brackets on each conductor supporting arm and a bolt securing the mounting bracket of the next higher arm along said tower, said bracing poles which extend upwardly to a bolt securing the mounting bracket on a conductor support arm being formed of non-conductive material to prevent arcing from adjacent conductors;
• c) means for adjusting the length of said bracing poles mounted intermediate their ends, whereby the length of said bracing poles may be adjusted for providing the desired bracing support to the conductor supporting arms to which said bracing poles are attached;
• d) a second clamping bracket on said bracing pole extending between said uppermost conductor support arm and a bolt securing the shield wire supporting arm mounting bracket to said tower;
• e) a rigid support strut extending diagonally downwardly between said first clamping bracket on said shield wire supporting arm and said second clamping bracket for providing bracing support to said shield wire supporting arm;
• and
• f) vibration dampers mounted to at least some of the conductor supporting arms on said tower.