The inspection of overheadcable is one of the basic contents of the operation and maintenance of overhead lines. Defects can be found in time through inspections so that preventive measures can be taken to ensure the safe operation of the line. Usually, line inspectors should do “nine inspections” when inspecting overhead lines.
Check the pole tower. Check whether the tower is collapsed, tilted, deformed, decayed, damaged, whether the foundation is cracked, and whether the iron components are bent, loose, skewed or rusted. Check whether the wire length of the iron bolts or iron screw caps of the tower is insufficient, the screws are loose, the binding wires are broken and loose. Check whether there are bird nests and other objects on the tower.
Second, check the crossarm and fittings. Check whether the cross arm and fittings are displaced, whether they are firmly fixed, whether the weld seam is cracked, whether the nut is missing, etc.
Three check the situation along the line. Check whether flammable, explosive or strongly corrosive substances are piled on the ground along the line, whether there are illegal structures near the line, whether there are buildings and other facilities that may harm the line during thunderstorms or strong winds; check the poles and towers Whether to erect other power lines, communication lines, broadcast lines, and install broadcast speakers, etc.; check whether the lines are connected to electrical equipment without authorization.
Four check the route. Check the wires and lightning protection wires for broken strands, back flowers, corrosion, damage from external forces, etc.; check whether the distance between the wires, the ground and adjacent buildings or adjacent trees, sag, etc. meet the requirements, and whether the sag of the three-phase wire is unbalanced Phenomenon: Check whether the wire connector is in good condition, whether there are signs of overheating, severe oxidation, and corrosion.
Five check insulators. Check the insulator for cracks, dirt, burns and flashover marks; check the deflection of the insulator string and the damage to the iron parts of the insulator.
Six check lightning protection devices. Check whether the size of the protection gap is qualified and whether the auxiliary gap is intact. Check whether the external gap of the tubular arrester changes and whether the grounding wire is intact. Check whether the porcelain sleeve of the valve-type arrester is cracked, dirty, burned, or flashover marks, and the sealing is good. Check whether the down conductor of the arrester is intact, whether the grounding body is exposed by water washing, and whether the connection between the grounding down conductor and the grounding body is firm.
Seven check pull lines. Check the power cable for rust, slack, broken strands and uneven force on each strand. Whether there is any decay or damage to the cable pile and protection pile Whether the cable anchors are loose, lack of soil and sinking of soil irrigation. Whether the wire rod, wedge-shaped wire clamp, UT-shaped wire clamp, and wire-holding hoop are corroded, whether the nut of the UT-shaped wire clamp is missing, and whether the stop device of the turnbuckle is in good condition. Whether the pull cord is pulled into the wood pole at the binding place.
Switch equipment on eight check poles. Check whether the switchgear is installed firmly, whether there is any deformation, damage or discharge traces, whether the operating mechanism is intact, and whether the distance between the leads and the ground meets the regulations.
Nine check crossing points. Check whether there are new crossing points, whether the crossing distance meets safety requirements, and whether the original crossing points endanger the safe operation of the line. Whether the protective measures are perfect.