I. Material Benefits of the 66 kV High-Voltage(FRP) Cross Arm
The appearance of FRP cross arms is basically the same as that of traditional composite material ones. But, in comparison with galvanized steel cross arms, FRP cross arms are only one-fourth to one-fifth as heavy and have a tensile strength over 500 MPa, which means more than 50% weight reduction. Their light weight enables easy manual handling, reduces the load on transmission towers, and lowers steel consumption, making them a cost-effective choice in general.
II. Characteristics and Value of Electrical(FRP) Crossarm Insulation
The 66 kV voltage level is not high, but the insulation requirement cannot be ignored. Ordinary steel crossarms are conductive; insulators have to be installed between the crossarm and conductors for normal operation, with strict specifications on both insulator height and creepage distance. The advantage of FRP cross arms is that they are inherently insulating; they are totally non-conductive and suitable for use in foggy weather, light rain, or humid coastal areas. The 66 kV composite-insulated crossarms have better insulation performance than conventional solid crossarms.
III. The Practical Value of(FRP) Cross Arms in Engineering
In recent years, several provinces and cities in China have started pilot tests of composite-insulated crossarms for transmission lines. During a technical renovation on an 110 kV line, a power supply company used composite-material insulated crossarms by replacing suspension insulators with these crossarms. This solution well solved the problem of insufficient conductor-to-ground clearance, greatly improving the line’s insulation performance, wind-induced alignment stability, and operation reliability. It is a mature product that can effectively solve the major problems encountered during grid operation.
IV. Selection and Installation Tips for(FRP) Cross Arms
The specific parameters of FRP insulated crossarms differ with each manufacturer; the right model should be chosen according to local environmental conditions and the actual operating needs of the substation. During installation, attention must be paid to component compatibility; metal parts and FRP materials have different thermal expansion coefficients. Forcing ordinary steel clamps onto these components may cause excessive local stress or even cracking due to temperature changes. Although FRP insulated crossarms are electrically insulating, their metal end fittings are conductive, so proper grounding is necessary. Moreover, FRP insulated crossarms made by pultrusion have excellent UV resistance.
