In international power distribution network projects, crossarms serve as critical components supporting insulators and conductors, and their material selection directly impacts the service life and operational maintenance costs of the transmission lines. Historically, steel crossarms dominated nearly all projects; however, over the past decade, fiber-reinforced plastic (FRP) crossarms have gained prominence in the power grid sector due to their exceptional performance. Many grid project teams face a dilemma when selecting materials: which option is more cost-effective? This article provides a detailed analysis from various practical application perspectives.
The crossbeam is a critical component that supports insulators and conductors
The primary consideration is material strength. Traditional steel crossarms have a higher material density: a 1.5-meter crossarm used for a 10 kV line can weigh over 10 kilograms. During pole installation, grid workers typically require two to three people to lift it, and high-altitude installation is particularly labor-intensive. In mountainous areas with poor transportation access, labor costs increase significantly. In contrast, fiberglass reinforced plastic (FRP) crossarms have a density of less than two-fourths that of steel; for the same dimensions, they weigh only about 5–6 kilograms, making them easy for a single worker to carry and enabling faster, less labor-intensive installation.
The density of the steel crossbeam is excellent.
When comparing their strength, steel crossarms exhibit superior density, whereas fiberglass reinforced plastic (FRP) crossarms typically meet the bending strength requirements for 10kV and 35kV lines, with even better impact resistance than steel. In the event of tree branch strikes or minor vehicle collisions, FRP crossarms do not deform or sink like steel; they remain functional as long as no cracks develop.
This highlights the primary advantage of fiberglass-reinforced plastic crossarms over steel ones. In regions with variable weather conditions and coastal areas, steel crossarms begin to rust gradually after three to five years of use, leading to corrosion-induced fractures. Consequently, they require regular painting maintenance, incurring substantial one-time costs. At a coastal facility, a six-year-operated transmission line was found to have half of its steel crossarms severely corroded and flaking; replacement was mandatory—a process that not only involved significant effort but also disrupted power supply operations.
FRP itself is an environmentally friendly and corrosion-resistant material.
Secondly, FRP itself is an environmentally friendly and corrosion-resistant material. In harsh environments such as those with extreme weather conditions, FRP crossarms do not rust or deteriorate, with a service life spanning up to thirty years. These crossarms require minimal maintenance or anti-corrosion treatment. They also exhibit excellent insulation properties—unlike steel crossarms, which are recommended for conductors, where flashover breakdown of insulators can easily trigger circuit tripping, FRP crossarms serve as superior insulators. Even if the insulators fail, they maintain their insulation performance, significantly reducing the likelihood of power outages—a critical advantage for power lines in mountainous and lightning-prone areas.
Many respondents in the survey consider FRP crossarms to be expensive; when considering their overall usage and costs, they may not prove cost-effective. FRP crossarms of the same model and size are priced over 100 yuan higher than steel crossarms, but the labor savings during installation offset this price difference. Additionally, requiring no maintenance or replacement for decades results in significantly lower operating costs compared to steel crossarms. It is important to note that FRP crossarms cannot withstand excessive overload forces, making them unsuitable for high-span, heavy-load high-voltage power grid projects. Therefore, under certain circumstances, steel crossarms are preferred, while FRP crossarms are currently more suitable for distribution network lines and rural grid upgrades.
FRP crossarms are currently more suitable for distribution network lines and rural grid upgrades.
In general, both fiberglass reinforced plastic (FRP) crossarms and traditional steel crossarms have their respective applications: For conventional distribution networks and rural grids—particularly in humid, corrosive, or lightning-prone areas—FRP crossarms offer greater time and labor efficiency over long-term use; whereas traditional steel crossarms are more suitable for high-load, high-voltage power lines in grid projects. When making a selection, avoid focusing solely on unit prices; instead, consider the overall context and budgeted maintenance costs.
