This is a common question, and understanding the difference helps clarify the structure of the entire power grid:

• Electricity Pylon (Transmission Tower): These are the large, tall, lattice or tubular steel structures that carry very high-voltage electricity (e.g., 110kV to 800kV and higher). Their purpose is to transmit large amounts of bulk power over long distances from generating stations to substations.

• Distribution Pole: These are the smaller, more numerous structures (often made of wood or concrete) found in neighborhoods. They carry lower-voltage electricity from substations directly to homes and businesses over shorter distances.

At Ningbo Changshi, our expertise and product lines span both of these critical areas. We offer the heavy-duty overhead transmission line equipment for constructing the transmission grid's pylons and conductors, as well as the essential overhead tools and accessories used for the day-to-day maintenance and construction of the local distribution network.

An electricity substation is a crucial hub within the electrical grid that facilitates the safe and efficient movement of power. Its primary function is to transform voltage to ensure electricity can be transmitted over long distances and then safely distributed to end-users. Substations can either step up the voltage for long-distance transmission or step down the voltage for local distribution.

Beyond voltage transformation, substations serve as central control points for the power system. They:

• Switch Circuits: Substations use circuit breakers and switches to connect and disconnect power lines, allowing utility operators to reroute power, isolate faulty sections of the grid, or perform maintenance without causing widespread outages.

• Protect the Grid: They contain a network of protective relays and other equipment that automatically detect faults (like short circuits or overloads) and quickly isolate the affected area, preventing damage to expensive equipment and ensuring grid stability.

• Regulate Voltage: Substations help maintain a stable voltage supply, which is critical for ensuring that all electrical devices operate correctly.

Our range of tools for electrical construction and maintenance are essential for these operations, from the initial build to ongoing inspections and repairs within the substation facility.

The construction and maintenance of a substation require a wide array of specialized tools and equipment to ensure safety and precision. While we don't manufacture transformers or circuit breakers, our one-stop supply includes a complete range of supporting equipment essential for the entire process:

• Cable Pulling & Laying Tools: For installing power cables, especially for underground substations.

• Conductor Stringing Tools: For connecting overhead power lines to the substation's switchyard.

• Lifting and Hoisting Equipment: To safely move heavy components and equipment within the substation yard.

• General Electrical Construction Tools: A variety of hand tools, safety equipment, and testing devices for a wide range of tasks, from terminating cables to working on control panels.

By providing this comprehensive range of overhead and underground tools, Ningbo Changshi supports our customers in every phase of substation projects, ensuring they have all the necessary equipment for a safe and successful job.

Substations are classified based on their role in the power grid. The two main types are:

• Transmission Substations: These are large, high-voltage stations located near power plants or along major transmission corridors. They use step-up transformers to increase the voltage for long-distance transmission or step down the voltage to connect to the sub-transmission network.

• Distribution Substations: These are smaller, more numerous stations located near neighborhoods and industrial areas. They take power from the transmission grid and use step-down transformers to lower the voltage to a level safe for local distribution to homes and businesses.

While types vary, the key components of almost every substation include:

• Transformers: The most important component, used to change voltage levels.

• Circuit Breakers: Used to interrupt current flow to protect against faults.

• Busbars: Conductors that connect the various circuits and components within the substation.

• Isolators: Switches used to physically isolate equipment for maintenance.

• Insulators: Devices that provide electrical insulation for the conductors.

The electricity supply chain is a multi-stage process that ensures power is delivered from the source to the end-user. It is typically broken down into four main stages:

1. Generation: This is where electricity is produced at power plants from various energy sources, such as coal, natural gas, nuclear, solar, or wind.

2. Transmission: The generated electricity's voltage is increased at a substation for efficient transport over long distances via high-voltage overhead power lines or underground cables.

3. Distribution: The electricity is then received at local substations, where the voltage is lowered to a safe level for delivery to homes and businesses through a network of smaller poles and wires.

4. Consumption: This is the final stage where the electricity is used by consumers for lighting, appliances, and industrial processes.

At Ningbo Changshi, our tools and equipment are central to both the transmission and distribution stages of this critical process.

While transmission and distribution are often grouped together, they are two distinct phases of the power delivery process, differentiated by voltage level and purpose:

• Transmission: This is the bulk movement of electricity over long distances. It operates at very high voltages (e.g., 115kV to 765kV) to minimize power loss. The transmission network consists of large, often metallic, towers and a web of interconnected lines that move power from generating stations to substations. Our Overhead Transmission Line (OHTL) Equipment, such as hydraulic tensioners and pullers, is specifically designed for the safe and efficient construction of this high-voltage network.

• Distribution: This is the final stage of delivery. It operates at lower voltages (e.g., below 34kV) and is a more localized network of smaller lines and poles that branch out from substations to individual customers. The distribution system is what you typically see running along neighborhood streets. Our Underground Cable Laying Equipment and general Overhead Tools and Accessories are essential for this part of the grid, which includes both overhead and underground power delivery.

By providing a one-stop supply for both types of projects, Ningbo Changshi is an essential partner for utility companies and contractors building and maintaining the entire power delivery infrastructure, from the largest transmission towers to the local distribution lines.

Electricity transmission towers, also known as pylons, are designed to support overhead power lines over long distances. While there are many variations, the two most common types are classified by their structural design:

• Lattice Steel Towers: These are the most prevalent type for high and extra-high voltage transmission lines. They consist of an open framework of steel angles and bracing, which provides immense strength and stability while remaining relatively lightweight. The lattice design is highly efficient and can be customized to suit various terrains and load requirements.

• Tubular Steel Poles (TSPs) or Monopoles: These towers are made from a single, tapered steel tube. They are visually more streamlined and have a much smaller footprint, making them ideal for urban areas or locations where aesthetics and limited space are a concern.

Additionally, towers can be classified by their function in the line: Suspension towers for straight runs, and Tension/Dead-end towers for turns, crossings, or line terminations. Our comprehensive OHTL Equipment supports all these tower types.

The construction of a transmission tower is a multi-stage process that requires meticulous planning, specialized tools, and a highly skilled crew. The general process includes:

1. Foundation Work: First, the site is prepared, and the tower's foundation is laid. This typically involves excavating the ground and pouring a concrete foundation to provide a stable base. Our foundation tools and accessories are used to ensure the anchor bolts and stubs are set with precise accuracy.

2. Tower Assembly: The pre-fabricated tower sections are delivered to the site. They are then assembled on the ground or hoisted in sections by cranes. Our hoisting and lifting equipment, including winches and gin poles, are essential for safely raising and assembling these heavy steel structures.

3. Conductor Stringing: Once the towers are erected and the insulators are installed, the most critical step begins: stringing the conductors. Our specialized overhead transmission line equipment, including hydraulic pullers and tensioners, are used to string the heavy conductor cables from tower to tower with the exact tension and sag required for the line to operate safely and efficiently.

4. Final Touches: After stringing, accessories like vibration dampers and spacers are installed, and the site is cleaned and restored to its original condition.

By offering a one-stop supply for all these phases—from foundation work to final stringing—Ningbo Changshi ensures our clients have the high-quality tools they need to complete their projects safely and on schedule.

While a transmission tower is a complete structure, it is comprised of several key parts, each with a specific function:

• Foundation: The base of the tower that anchors it securely to the ground.

• Tower Body/Legs: The main vertical structure that supports the entire tower.

• Cross-Arms: The horizontal arms that extend from the tower body. They hold the insulators and conductors. The number and length of cross-arms depend on the voltage and number of circuits.

• Insulators: Made of porcelain or composite materials, these are crucial for electrically isolating the live conductors from the tower body, which is grounded.

• Conductors: The actual wires or cables that carry the electricity.

• Overhead Ground Wire (Shield Wire): A wire located at the very top of the tower, used to protect the conductors below from lightning strikes.

All of our overhead tools and accessories are designed to work seamlessly with these components, making us a reliable partner for the construction and maintenance of power grids worldwide.

While the concept of transmitting electricity through the air has captured the public's imagination since the time of Nikola Tesla, it is not a feasible or efficient solution for a large-scale power grid. While electricity can be transmitted short distances without wires (e.g., through inductive charging), long-distance transmission through the air faces significant technical and efficiency challenges.

• Significant Energy Loss: Transmitting power through the air over long distances is highly inefficient. The energy would dissipate rapidly as it travels, with a significant portion being lost to the atmosphere and the surrounding environment. This makes it a very impractical and costly method for bulk power delivery.

• Safety Concerns: High-power wireless transmission would pose immense safety risks to humans, animals, and the environment. The high levels of electromagnetic radiation required to transmit power could be hazardous to living organisms and could interfere with other electronic systems.

• Feasibility and Cost: The infrastructure required for a wireless power grid would be astronomical to build and maintain, far outweighing the cost of the existing wired grid.

For these reasons, the most efficient, safe, and reliable method for bulk power transmission remains the use of high-voltage conductors, which is the foundation of our business.

Wireless charging for small devices like smartphones and electric toothbrushes is a form of wireless power transfer, but it operates over very short distances using a principle called electromagnetic induction.

• Transmitter and Receiver Coils: The charging pad (transmitter) contains a coil of wire, and the device being charged (receiver) has a similar coil.

• Magnetic Field Generation: When electricity flows through the transmitter coil, it creates a magnetic field.

• Induced Current: When the receiver coil is placed in close proximity to this magnetic field, the field induces an electrical current in the receiver coil, which then charges the device's battery.

This technology is highly efficient and safe, but only over very short, controlled distances (a few millimeters to centimeters). It is not a viable technology for transmitting the massive amounts of power required to run a city or factory.

The existing power grid, with its system of overhead and underground conductors, remains the most effective solution for a modern society. It is based on the proven principles of electromagnetic conduction, which offer:

• Maximum Efficiency: Wired systems can transmit power over hundreds of kilometers with minimal energy loss (typically less than 5%), which is far superior to any long-distance wireless method.

• Safety and Reliability: The physical conductors are contained and insulated, ensuring a predictable and secure power supply that is not susceptible to atmospheric interference or health risks from stray radiation.

• Scalability: The current grid is a robust, interconnected system that can handle fluctuations in supply and demand, a capability that wireless transmission technology simply cannot match today.

At Ningbo Changshi Electric Power Machinery Manufacturing Limited, our mission is to provide the highest quality tools and equipment for this proven and reliable grid. From our OHTL wire cable conductor tension stringing equipment to our underground cable laying equipment, we ensure that every stage of power transmission and distribution is built to be as efficient and safe as possible, guaranteeing a sustainable energy future.

The primary difference lies in the type of current used: Alternating Current (AC) or Direct Current (DC). Both have specific applications and advantages in the power grid.

• High-Voltage Alternating Current (HVAC): This is the most common type of transmission system used globally. Its key advantage is the ease with which voltage can be stepped up or down using transformers, making it highly flexible for an interconnected grid. HVAC is most economical for short to medium distances and is the standard for power distribution to homes and businesses.

• High-Voltage Direct Current (HVDC): HVDC transmission is the preferred method for transmitting large amounts of power over very long distances (e.g., hundreds or thousands of kilometers), particularly for connecting remote power sources like hydro or wind farms to urban centers. Its main advantages are significantly lower power loss over long distances and its ability to connect two different AC power grids that are not synchronized. HVDC is also the only feasible option for long-distance submarine or underground power cables.

Our OHTL wire cable conductor tension stringing equipment is widely used for both HVAC and HVDC overhead lines, ensuring the precise and efficient installation of conductors for any project, regardless of the current type.

Electricity can be transmitted through conductors either above or below the ground. The choice between overhead and underground systems depends on factors like cost, environment, safety, and capacity.

• Overhead Transmission: This is the most common and cost-effective method for long-distance transmission. It involves bare conductors suspended from poles or lattice towers. Its advantages include lower installation costs, easier maintenance, and higher capacity for bulk power transfer. However, it is vulnerable to weather events and has a significant visual impact.

• Underground Transmission: This method involves insulated cables buried in trenches, ducts, or tunnels. It is more expensive to install but offers a higher level of public safety, is protected from extreme weather, and has a minimal visual footprint. It is the preferred choice for densely populated urban areas, sensitive natural environments, and river or sea crossings.

Our comprehensive product line includes both Overhead Transmission Line Equipment for the construction of towers and stringing overhead conductors, and a complete suite of Underground Cable Laying Equipment for projects that require power to be delivered beneath the ground.

The equipment used for electricity transmission and construction is highly specialized and can be categorized into three primary areas, each with a distinct function in building and maintaining the power grid.

1. Overhead Transmission Line (OHTL) Equipment: This category includes the heavy machinery and tools used to build and maintain the massive overhead power lines that carry electricity over long distances. The key equipment in this category is our wire cable conductor tension stringing equipment, which includes:

   • Hydraulic Pullers: Used to pull the conductor from a drum to the next tower.

   • Hydraulic Tensioners: Used to apply back tension to the conductor, ensuring it is installed with the correct sag and tension to prevent damage.

   • Anti-twisting Steel Ropes, Swivels, and Connectors: Critical accessories for the stringing process.

2. Underground Cable Laying Equipment: As a growing alternative, underground power lines require a different set of tools and machinery to install cables safely beneath the ground. This includes specialized equipment like:

   • Cable Pulling Winches: Used for pulling heavy cables through trenches or ducts.

   • Cable Rollers and Sheaves: To guide cables during the laying process.

   • Cable Stand Jacks: Used to support cable drums and facilitate unwinding.

3. Substation and General Electrical Construction Tools: In addition to the large machinery, a wide array of tools is required for the construction, maintenance, and repair of substations and other electrical infrastructure. These include safety equipment, grounding tools, cable cutters, crimpers, and a variety of specialized hand tools.

As a prominent manufacturer and exporter, Ningbo Changshi is proud to offer a comprehensive, one-stop supply of all these categories of equipment.

Electrical transmission is also categorized by its voltage level, which directly impacts its purpose and the distance it can cover.

• High-Voltage (HV): Typically operating at 115 kV to 230 kV, this is used for regional transmission networks, connecting major substations and cities.

• Extra-High Voltage (EHV): Operating at 345 kV to 765 kV, EHV lines form the core "superhighway" of the power grid, transmitting electricity in bulk over vast distances.

• Ultra-High Voltage (UHV): Operating at 800 kV and higher, UHV is the most advanced form of transmission, designed for maximum efficiency over extremely long distances, often used in large countries to move power from remote generation sources to demand centers.

At Ningbo Changshi, our tools and equipment are built to meet the rigorous demands of projects at every voltage level, ensuring that our customers have the reliable and high-performance equipment they need to build and maintain the power grids of today and tomorrow.

Ultra-High Voltage (UHV) transmission refers to electricity transmission at voltages of 800 kV and higher. It is a technological leap in power transmission, designed to meet the growing global demand for electricity while addressing the challenges of efficiency and sustainability.

Why UHV is Used:

• Minimizes Power Loss: The primary advantage of UHV is its ability to transmit a massive amount of power over thousands of kilometers with significantly less energy loss. Power loss is proportional to the square of the current, so by increasing voltage, UHV reduces the current needed for the same amount of power, drastically cutting down on energy wasted as heat.

• Enables Remote Energy Integration: UHV is essential for connecting large-scale, remote renewable energy sources (like hydropower dams in the mountains or solar farms in deserts) to distant population and industrial centers.

• Reduces Land Use: By carrying more power on each line, a single UHV line can replace multiple lower-voltage lines, reducing the overall right-of-way needed for the grid.

At Ningbo Changshi, we understand that UHV requires the most advanced and robust tools. Our specialized OHTL wire cable conductor tension stringing equipment is engineered to handle the larger, heavier, and more complex conductor bundles used in UHV projects, ensuring precision and safety.

UHV transmission, while highly efficient, introduces unique technical challenges that require specialized solutions and equipment.

• Insulation: The immense voltage requires greater air clearances between conductors and the tower body to prevent arcing. This demands larger, more robust insulators and carefully designed tower structures.

• Corona Discharge: At such high voltages, the electric field around the conductors can ionize the air, causing a "corona" effect, which results in power loss, audible noise, and radio interference. To mitigate this, UHV lines use bundled conductors, where each phase consists of multiple sub-conductors arranged in a bundle.

• Specialized Equipment: The massive scale of UHV projects, with heavier conductors and greater spans, requires highly specialized construction equipment.

Our company, Ningbo Changshi, provides the critical tools to overcome these challenges. Our hydraulic tensioners and pullers are designed with the high torque and precision needed to safely string the large, bundled conductors for UHV lines, and our general overhead tools and accessories are built to meet the rigorous safety and performance standards of these demanding projects.

The construction of an overhead power line is a complex process that requires specialized tools for each stage. While the overall process involves ground work and tower erection, the most critical phase is the conductor stringing. To build an overhead power line efficiently and safely, you need:

• Hydraulic Tensioners and Pullers: These are the core machines for conductor stringing. The puller pulls the conductor across the line, while the tensioner controls the back tension to ensure the conductor is installed correctly.

• Conductor Stringing Blocks/Sheaves: Mounted on the towers, these guides allow the conductor to be pulled smoothly from one span to the next.

• Anti-Twisting Steel Ropes: Used for pulling conductors to prevent rotation and ensure a smooth stringing process.

• Swivels and Joints: To connect the pull rope to the conductor and allow for rotation-free pulling.

We specialize in all the essential Overhead Transmission Line Equipment for this process, ensuring our clients can handle any project, from a standard power line to a massive UHV project with bundled conductors.

The main difference lies in the fundamental process. Overhead projects are about tensioning and stringing cables from above, while underground projects are about pulling and laying cables from below.

• Overhead tools are designed for stringing cables under controlled tension over long spans, often across challenging terrain. The machinery, like tensioners and pullers, is built to be powerful and precise to handle the weight and tension of long conductor runs.

• Underground tools are designed for pulling cables through ducts or open trenches. The equipment, such as cable pulling winches and rollers, focuses on guiding and pulling the cables without damaging their insulation as they are laid below ground.

Our company's unique position as a comprehensive one-stop supplier means we have the expertise and product lines for both types of projects, allowing our clients to source all their necessary equipment from a single, trusted partner.