notizie sull'azienda How to Select a Hydraulic Puller for Single, Twin and Four-Bundle Conductor Stringing

Bundle configuration is the single most decisive factor when selecting a hydraulic puller. Whether a line carries a single conductor, twin-bundle or four-bundle sub-conductors changes the total load, the number of tensioner channels, and ultimately the machine class you need. This article walks through how to make that call.

The Five Core Variables

• Conductor number — one, two or four sub-conductors per phase.
• Cross-section — the size and type (ACSR, AAAC, ACAR) determines weight per metre.
• Terrain — flat, hilly or mountainous ground changes effective load and section length.
• Required pull — the total force needed to complete the pull with margin.
• Stringing speed — the pace the schedule demands over the section.

Single Conductor

Single-conductor stringing presents the lightest load. A compact puller with modest force capacity is usually sufficient, and transportability becomes the dominant concern because these lines often run through congested or remote corridors. Speed and reliability matter more than brute force.

Twin-Bundle Conductor

Twin-bundle conductor doubles the conductor load and requires two tensioner channels working in balance. A 90 kN class puller, such as the GS90, is well suited to twin-bundle work: it is specified for the appropriate twin-bundle conductor range, offers enough pulling force for moderate sections, and pairs naturally with a dual-channel tensioner. This is the workhorse configuration for many 220 kV projects.

Four-Bundle Conductor

Four-bundle conductor multiplies the load again and is characteristic of EHV lines. Here the puller must deliver substantially higher pulling force and maintain it continuously over long sections. The GS150 and GS220 class machines cover four-bundle applications, with continuous pulling ratings designed to keep four sub-conductors moving steadily without stalling. At this level, the tensioner side must also scale up to hold four channels under stable tension.

Don't Ignore Speed and Terrain

Two projects with identical conductor can still need different machines if one runs across flat farmland and the other climbs a mountain. Steep terrain reduces practical pulling speed and increases the effective load, often pushing the requirement up a class. Always check the puller’s rated stringing speed under your terrain conditions, not just its peak force. Section length interacts with all of this as well: a long four-bundle pull compounds friction and load over distance, so the machine’s continuous rating matters more than its short-term peak. When these five variables — conductor number, cross-section, terrain, required pull and stringing speed — are confirmed, selecting the puller becomes a straightforward match to the appropriate class.