Answer: This is a common point of confusion. Electricity transmission lines carry large amounts of power at very high voltages over long distances, typically from power plants to regional substations. They are often supported by large, lattice-steel towers. In contrast, distribution lines transport power from substations to end-users (homes, businesses) at lower voltages and over shorter distances. Distribution lines are usually found on smaller wooden or steel poles in residential and urban areas. We specialize in providing the heavy-duty equipment and tools, such as tension stringing equipment and hydraulic compressors, for the construction and maintenance of these high-voltage transmission lines.

Answer: An overhead electricity transmission line consists of several essential components that work together to ensure reliable power delivery. The primary components are:

• Conductors: The actual wires that carry the electrical current. They are typically made from aluminum with a steel core for strength, known as ACSR (Aluminum Conductor Steel Reinforced).

• Insulators: These are crucial for preventing the electrical current from leaking to the supporting structure and the ground. They are made from materials like porcelain, glass, or polymers and are attached to the towers or poles.

• Support Structures: These are the towers or poles that keep the conductors suspended at a safe height. They can be lattice-steel towers, tubular steel poles, or wooden poles, depending on the voltage and terrain.

• Hardware and Fittings: A variety of clamps, connectors, and other accessories are used to secure the conductors to the insulators and the structures.

Ningbo Changshi manufactures and exports a comprehensive range of these tools and accessories, including hydraulic wire cutters, come-along clamps, and conductor drum lifting jacks, to support every stage of an overhead line project.

Answer: The cost of an electricity transmission line is not a single fixed value but varies significantly based on several factors. Key influencers include:

• Type of Construction: Overhead lines are typically the most cost-effective. Underground cables, while having aesthetic and environmental benefits, can be 5 to 10 times more expensive due to excavation, specialized insulation, and complex installation processes. We offer a full range of equipment for both methods, from overhead line stringing tools to powerful underground cable laying equipment.

• Voltage and Capacity: Higher voltage lines (e.g., 500 kV vs. 132 kV) require larger, more robust towers, heavier conductors, and more sophisticated insulators, all of which increase costs. The higher the power capacity, the more expensive the components.

• Terrain and Location: Constructing lines in challenging terrains like mountains, swamps, or dense urban areas is far more expensive than in open, flat land. The cost of labor, land acquisition, and permitting also varies greatly by region and country.

• Components and Materials: The specific type of conductors (e.g., ACSR, AAAC), insulators (polymer vs. glass), and hardware fittings all contribute to the final price. The selection of these materials is a key part of the project's overall budget.

Answer: The process of delivering electricity can be broken down into three main stages: Generation, Transmission, and Distribution. Our company specializes in providing the tools and equipment necessary for the critical transmission and distribution phases.

1. Generation: This is where electricity is produced at a power plant using various sources, such as coal, natural gas, nuclear energy, wind, or hydropower. The electricity is generated at a relatively low voltage.

2. Transmission: To transport electricity efficiently over long distances, the voltage is "stepped up" significantly at a substation near the power plant. This high-voltage electricity then travels along high-capacity transmission lines, which are often visible as large towers or poles. Our company provides a wide array of equipment for both overhead transmission line (OHTL) stringing and underground cable laying, ensuring reliable power transfer.

3. Distribution: As the electricity approaches populated areas, it passes through various substations where the voltage is gradually "stepped down" to a level suitable for homes and businesses. From these substations, it is carried by smaller distribution lines (the wires you see on local streets) to final end-users. We offer a comprehensive one-stop supply of tools for this entire process, including overhead tools and accessories, and underground cable laying equipment.

Answer: Electricity transmission is a highly efficient process, but some energy is inevitably lost as it travels from the power plant to the consumer. This is primarily due to the physical properties of the conductor and the electrical current itself.

The main types of power losses are:

• Resistive Losses (I²R losses): This is the most significant form of loss. When current (I) flows through a conductor, the resistance (R) of the material causes some of the electrical energy to be converted into heat. This loss is directly proportional to the square of the current and the resistance of the conductor.

• Corona Losses: Occurs when the electric field intensity around the conductor is so high that it ionizes the air, leading to a visible glow and an audible hum, which results in energy loss.

• Dielectric and Leakage Losses: These are minor losses caused by energy dissipation in the insulating materials and leakage current to the ground.

To effectively reduce these losses, our industry focuses on several key strategies:

• Increasing Voltage: We transmit electricity at extremely high voltages. This is because, for a given amount of power, increasing the voltage reduces the current. Since resistive loss is proportional to the square of the current (I²), a lower current drastically reduces energy loss.

• Improving Conductor Material: Using high-quality conductors with lower resistance, such as aluminum reinforced with steel, is crucial. Our company provides advanced overhead transmission line (OHTL) wire cable conductor tension stringing equipment to ensure the proper and secure installation of these high-performance conductors.

• Optimizing Grid Infrastructure: Implementing advanced technologies like power factor correction, using more efficient transformers, and carefully designing the network topology all contribute to minimizing losses. Our expertise extends to providing equipment for substations and electrical construction, which are critical components in creating an optimized and efficient power grid.

Answer: Ring-fencing in the electricity sector is a regulatory framework that requires a network service provider to separate its regulated business activities (e.g., operating the monopoly transmission network) from its competitive business activities (e.g., providing other commercial services like equipment installation or maintenance).

The primary purpose of ring-fencing is to:

• Prevent cross-subsidization: It stops a company from using revenue from its regulated, monopoly business to unfairly subsidize its competitive services, which would create an unlevel playing field.

• Ensure non-discriminatory behavior: It guarantees that the network service provider treats all competitors—including its own related businesses—fairly and equally when providing access to essential network information or services.

• Promote competition: By fostering a fair and competitive market, ring-fencing encourages other businesses to enter the market for services like connection work, which can lead to innovation, efficiency, and better outcomes for consumers.

Our company, Ningbo Changshi, supplies the essential overhead transmission line equipment and underground cable laying equipment that are used by all parties—both the network service providers and their competitors—in the competitive electricity services market. These guidelines directly contribute to the growth and fairness of the markets we serve.

Conductor stringing is the process of installing the electrical wires (conductors) for overhead transmission lines onto the supporting towers. There are two primary methods:

• Slack Stringing: This is a traditional method where the conductor is pulled in a loose or "slack" manner, often allowing it to touch the ground or other obstacles. This method is generally less expensive but can risk damaging the conductor.

• Tension Stringing: This is the modern, preferred method, especially for high-voltage projects. The conductor is pulled under controlled tension, keeping it clear of the ground and other obstructions throughout the entire process. This minimizes potential damage to the conductor, protects the surrounding environment, and ensures a higher quality, more reliable installation.

Ningbo Changshi is a leading provider of high-quality tension stringing equipment, which is essential for safe and efficient conductor installation on overhead transmission lines.

An overhead transmission line is a complex system composed of several key components that work together to ensure safe and reliable power delivery. The primary components are:

• Conductors: These are the actual wires that carry the electrical current. They are typically made of aluminum with a steel core for added strength (ACSR - Aluminum Conductor Steel Reinforced).

• Insulators: Made from materials like porcelain, glass, or polymers, insulators are crucial for preventing the electrical current from flowing from the conductor to the supporting tower or pole.

• Support Structures: These are the towers or poles that physically support the conductors and insulators, keeping them elevated and separated from the ground and each other. Common types include lattice steel towers and tubular steel poles.

• Overhead Ground Wires (or Shield Wires): These are wires positioned at the very top of the towers to protect the phase conductors from lightning strikes.

• Hardware and Accessories: This includes a wide range of fittings, clamps, spacers, and dampers used to secure the conductors to the insulators, maintain proper spacing, and prevent vibration damage.

Our company specializes in manufacturing a comprehensive range of equipment and tools for the construction and maintenance of these vital components.

The Ferranti Effect is a phenomenon in long AC transmission lines where the receiving end voltage is higher than the sending end voltage. This occurs under light load or no-load conditions due to the line's capacitance. The effect can be problematic as it can damage equipment and cause system instability.

To address the Ferranti Effect, various methods are used, including:

• Shunt Reactors: These are devices installed along the transmission line to absorb the excess reactive power generated by the line's capacitance, thereby controlling and stabilizing the voltage.

• Synchronous Condensers: These rotating electrical machines can be used to either generate or absorb reactive power to regulate the voltage.

As a provider of comprehensive equipment for substations and power line maintenance, Ningbo Changshi offers solutions and tools to support the installation and upkeep of such voltage control systems.

The most common problems in 3-phase power systems often stem from factors like poor connections, insulation deterioration, and external events. These can lead to issues such as phase imbalance, voltage sags and surges, and short circuits. Such faults can cause equipment damage and power outages. To prevent these issues, regular inspection and maintenance are crucial. Our company provides a full range of overhead tools and accessories that are essential for the safe and effective inspection and repair of transmission lines, helping to ensure system reliability and operational safety.

Answer: Electrical transmission lines are classified primarily based on two key factors: the length of the line and the voltage level they carry.

• By Length: This is the most common method of classification, as the length determines the electrical model used for analysis.

  • Short Transmission Lines: Generally, lines with a length of up to 80 km (50 miles). For these lines, the effects of capacitance are negligible and are not considered in calculations.

  • Medium Transmission Lines: Lines ranging from 80 km to 240 km (50 to 150 miles). For these, the capacitance effects are significant and are accounted for by using a "lumped" model where capacitance is concentrated at one or more points along the line.

  • Long Transmission Lines: Lines that exceed 240 km (150 miles). For long lines, all electrical parameters—resistance, inductance, and capacitance—are considered uniformly distributed along the entire length, requiring more complex analysis.

• By Voltage: Transmission lines are also categorized by the voltage they carry. While specific ranges can vary by region, a general classification includes:

  • Low Voltage (LV): Up to 1 kV.

  • Medium Voltage (MV): 1 kV to 69 kV.

  • High Voltage (HV): 69 kV to 230 kV.

  • Extra-High Voltage (EHV): 230 kV to 800 kV.

  • Ultra-High Voltage (UHV): Above 800 kV.

Answer: While AC (Alternating Current) is the predominant method for power generation and distribution, DC (Direct Current) is highly efficient for long-distance and specialized applications.

• AC Transmission: AC systems are widely used due to the ease of stepping up or stepping down voltage with transformers, making them cost-effective for short and medium distances. However, they experience losses from reactive power, skin effect, and corona discharge, which become more pronounced over long distances. AC lines typically use three conductors.

• DC Transmission: DC systems are ideal for long-distance power transmission and submarine cables because they have lower power losses. They do not suffer from reactive power or skin effect, which makes them more efficient. While the terminal equipment (converters) is more expensive, the reduced line losses over long distances often make HVDC (High-Voltage Direct Current) more economical. DC lines require fewer conductors, typically one or two.