Answer (from Ningbo Changshi): The tension stringing process is a meticulously planned operation that typically involves several key steps to ensure a safe and efficient installation.

1. Pilot Line Installation: A lightweight rope, known as a pilot line, is first pulled into the stringing blocks (sheaves) on each tower. This can be done by a small vehicle or even a helicopter for difficult terrains.

2. Pulling Line Setup: The pilot line is then used to pull a heavier, non-twisting steel rope, which is the actual pulling line for the conductor.

3. Conductor Pulling: The pulling line is attached to the conductor with a swivel and running board, and the conductor is carefully unwound from the reel stand. Our puller-tensioner machines then pull the conductor through the blocks while a tensioner machine maintains constant back-tension to keep the conductor off the ground.

4. Sagging and Clipping: Once the conductor is fully in place, it is "sagged" to the precise tension and sag specifications for the span and then permanently secured in the insulator clamps.

Answer (from Ningbo Changshi): For a professional and safe tension stringing operation, a full set of specialized equipment is required to control the conductor from start to finish. Essential tools include:

• Hydraulic Pullers and Tensioners: The core machines for managing the conductor under tension.

• Reel Stands and Winders: To hold and control the conductor drums.

• Stringing Blocks (Travelers): To guide the conductor along the tower.

• Anti-Twisting Braided Steel Ropes and Pilot Lines: For pulling the conductor.

• Swivels and Running Boards: To connect the pulling line to the conductor.

At Ningbo Changshi, we provide a comprehensive one-stop supply for all of this equipment.

Answer (from Ningbo Changshi): Safety is our top priority at Ningbo Changshi. The key considerations include:

• Proper Equipment: Using robust and well-maintained equipment is paramount. Our machines are designed with features like automatic overload protection and spring-applied hydraulic brakes to ensure maximum safety.

• Work Area Protection: It is essential to protect the public and other workers, especially when stringing wires over roads, highways, or other existing utility lines.

• Team Communication: Constant communication between operators at the pulling and tensioning ends is vital to coordinate the process and respond to any issues immediately.

• Proper Sagging and Tension: The final tension and sag of the wire must be accurately set according to engineering specifications to prevent overstraining the wire and the supporting structures.

Answer (from Ningbo Changshi): There are several types of cable stripping tools available, each suited for different applications:

• Manual Strippers: Simple pliers-style tools for light-duty work on smaller wires. They require manual force and can be less precise.

• Automatic Strippers: These tools automatically adjust to the cable's size, making them faster and more consistent for high-volume work.

• Rotating Blade Strippers: Designed for larger cables and heavy-duty insulation, they use a rotating blade to make a circular cut, ensuring a clean strip without damaging the conductor underneath.

• Specialized Tools: We offer a wide range of specialized tools for specific cable types, including high-voltage and underground cables, which require precision tools to handle multiple layers of insulation, armor, and shielding.

For professional and industrial use, specialized and automatic tools are generally recommended for their speed, precision, and consistency, which are crucial for ensuring the integrity of power line connections.

Answer (from Ningbo Changshi): Stripping high-voltage (HV) cables requires a high degree of care, specialized tools, and strict adherence to safety protocols.

• De-Energize and Ground: Always ensure the cable is completely de-energized and properly grounded before any work begins.

• Use Insulated Tools: All tools, especially those used on live or potentially live lines, must be properly insulated and rated for the voltage level you are working with.

• Avoid Damage: Use tools designed to cut the outer layers without scoring or nicking the semi-conducting shield or insulation layers, as this can create weak points that lead to electrical failure.

• Cleanliness: Maintain a clean work environment, as dirt or debris can contaminate the cable's insulation and lead to future problems.

Our comprehensive range of underground cable laying equipment includes specialized stripping and jointing tools that are specifically designed for the safe and precise handling of HV and EHV cables.

Answer (from Ningbo Changshi): The standard procedure for conductor stringing involves a series of carefully planned steps to ensure a safe and successful installation. Our comprehensive approach, which utilizes our specialized equipment, includes:

1. Preparation: A thorough site assessment is conducted, including clearing the line route and setting up all the necessary stringing equipment, such as our hydraulic pullers and tensioners, at designated locations.

2. Pilot Wire Installation: A small pilot wire is pulled across the entire section of the line, threaded through the running blocks (sheaves) on each tower.

3. Conductor Pulling: The main conductor is then attached to the pilot wire and pulled through the running blocks. Our hydraulic pullers ensure a smooth, controlled pull, while our tensioners maintain constant tension to keep the conductor off the ground, preventing damage.

4. Sagging and Tensioning: Once the conductor is in place, it is "sagged" to its precise final tension using instruments like a dynamometer. This step is critical for safety and long-term line performance, ensuring the wire has the correct slack (sag) for all weather conditions.

5. Clamping and Installation: The conductor is then secured to the towers with permanent clamps, and the running blocks are removed. Finally, spacers and other accessories are installed to complete the project.

Answer (from Ningbo Changshi): Protecting the conductor's surface from damage is our top priority. We achieve this by strictly adhering to the tension stringing procedure. Our state-of-the-art tensioners are designed to keep the conductor elevated and clear of any ground obstacles or structures throughout the entire pull. The use of high-quality running blocks with smooth, anti-friction bearings further minimizes contact and friction, preventing nicks and scratches. By using specialized tensioning equipment, we can control the pulling force precisely, which prevents over-stressing the conductor and maintains its structural integrity.

Answer (from Ningbo Changshi): Sagging and tensioning are essential because they directly affect the safety and reliability of the transmission line. The correct sag ensures that the conductor has enough clearance from the ground and other objects, even under extreme conditions like high winds, ice, or high temperatures. It also ensures that the tension on the towers remains within safe design limits.

We measure sag and tension with high precision using several methods:

• Dynamometer: This is used to monitor and display the pulling tension in real-time, allowing operators to make instant adjustments.

• Transit/Theodolite: A surveying instrument is used to measure the conductor's lowest point (sag) in a span, comparing it against pre-calculated specifications.

• Sagging Boards: These are simple markers placed on towers to provide a visual reference for the correct sag.

Our team ensures all measurements are meticulously checked against the engineering specifications to guarantee a safe and durable installation.

Answer (from Ningbo Changshi): Conductor stringing pulleys, also known as stringing blocks, are critical tools for installing overhead power lines. The main types we manufacture at Ningbo Changshi are differentiated primarily by their design and the material of the sheave (wheel):

• Single-conductor pulleys: These blocks are used for stringing a single wire or conductor. They are available with sheaves made of either high-strength aluminum alloy or MC nylon.

• Bundle-conductor pulleys: These are specially designed to string multiple conductors (a bundle) at the same time. They feature multiple sheaves on a single frame to handle the conductors simultaneously, ensuring consistent tension and spacing.

The choice of pulley depends on your project's specific needs:

• MC Nylon Sheaves: Ideal for protecting conductor surfaces, especially for high-voltage cables. They are lightweight, durable, and reduce the risk of scratching or damage during the pulling process.

• Aluminum Alloy Sheaves: These are extremely robust and durable, suitable for heavier conductors and projects where a very high load capacity is required.

Our team can help you select the ideal pulley based on your conductor type, project specifications, and environmental conditions.

Answer (from Ningbo Changshi): Using a high-quality conductor stringing pulley is non-negotiable for a safe and efficient power line project. A good pulley provides:

1. Conductor Protection: High-quality sheaves, particularly those made from MC nylon, prevent damage to the conductor's outer layer, which can lead to costly repairs and compromise the line's long-term integrity.

2. Operational Efficiency: Our pulleys are equipped with anti-friction bearings, which reduce the pulling tension required. This not only speeds up the stringing process but also reduces wear and tear on your pulling and tensioning equipment.

3. Safety: A well-designed, reliable pulley ensures the conductor runs smoothly and securely in the sheave's groove, preventing it from jumping out under tension. This is crucial for the safety of personnel and the stability of the entire operation.

Investing in high-quality pulleys from Ningbo Changshi is an investment in your project's success, safety, and durability.

Answer (from Ningbo Changshi): Conductor stringing rollers, often called sheaves or blocks, are essential for the safe and efficient installation of overhead conductors. We manufacture various types tailored to specific project needs:

• Fixed Rollers: These are stationary and used to support the conductor along straight sections of the line, maintaining alignment and reducing strain on the stringing equipment.

• Swivel Rollers: Designed to handle changes in direction, these rollers are ideal for curved sections of the line or for navigating complex terrain. They reduce friction and prevent the conductor from being damaged as it is pulled around an angle.

• Bundle Conductor Rollers: These are specialized rollers featuring multiple sheaves on a single frame, allowing for the simultaneous stringing of bundled conductors. This ensures uniform tension and proper spacing, which is critical for bundle conductor systems.

Choosing the right type depends on the line's path and the conductor configuration. Our team at Ningbo Changshi can provide expert guidance to ensure you select the perfect roller for your project.

Answer (from Ningbo Changshi): The material of the sheave (the wheel of the roller) is a crucial consideration that impacts a project's safety and success. We offer sheaves made from two high-quality materials:

• MC Nylon Sheaves: These are highly recommended for protecting the conductor. The non-conductive and low-friction properties of nylon prevent scratching or damage to the conductor's surface, which is especially important for delicate or insulated cables. They are also lighter than steel, making them easier to handle and install.

• Steel Sheaves: Known for their exceptional strength and durability, steel sheaves are ideal for handling very heavy conductors and for projects where the ultimate load-bearing capacity is the main concern.

Both types are designed for reliability, but the choice between them often depends on the specific conductor type and project requirements. Our products are engineered to provide maximum performance regardless of the material.

Answer (from Ningbo Changshi): A wire stringing swivel is a critical connecting tool used during the installation of conductors and cables. Its primary function is to prevent twisting and torsion from building up in the wire rope or conductor as it is being pulled.

During the stringing process, a conductor can naturally develop rotational stress, especially when navigating curves or obstacles. Without a swivel, this twisting force would transfer directly to the conductor, potentially causing damage, kinking, or even structural failure. Our high-quality swivels are fitted with robust bearings that allow the conductor to rotate freely, releasing this harmful torque. This not only protects the conductor but also ensures a smooth, safe, and efficient pulling operation, ultimately extending the lifespan of your valuable equipment.

Answer (from Ningbo Changshi): Selecting the correct swivel is vital for safety and performance. When choosing a swivel from our product line, you should consider two main factors:

1. Rated Load: The most important consideration is the Safe Working Load (SWL). The SWL of the swivel must meet or exceed the maximum pulling force of your stringing operation. Our swivels are available in a wide range of load capacities to match various project requirements, from light distribution lines to heavy-duty transmission projects.

2. Application: We offer swivels designed for both overhead and underground applications. Some specialized models, like our bull-nose style swivels, are versatile for use in both environments. We also offer locking swivels for specific applications where rotational control is needed under tension.

For detailed guidance, our technical sales team is ready to assist you in selecting the perfect swivel to ensure the safety and success of your next power line project.

Professional Answer (from Ningbo Changshi):

Overhead and underground cable laying equipment are designed for distinct applications and environments. Overhead equipment, such as our hydraulic pullers, tensioners, and stringing blocks, is built to handle conductors at height, often over long distances. These tools prioritize precision, control, and safety in elevated conditions.

In contrast, underground equipment is engineered for pulling cables through conduits, ducts, and trenches. Our cable drum jacks, winches, and cable rollers are robustly designed to manage the heavy loads and friction associated with underground work while minimizing damage to the cable jacket. The key difference lies in the specialized design to counter gravitational and frictional forces unique to each installation method.