In the Huishui County Economic Development Zone of Guizhou Province, Guizhou Tianhong Zhiyuan Wire and Cable Co., Ltd. (hereinafter referred to as "Tianhong Cable") has diligently cultivated its internal strength, focusing on market demand and conducting scientific and technological research. With each cable produced, it has carved a niche in the market and grown into a national-level "little giant" enterprise specializing in specialized, innovative, and innovative products. By 2023, Tianhong Cable had produced over 54,000 kilometers of various types of wire and cable, more than enough to circle the Earth.

"Hard-core" cable burns for 3 hours without power outage

As the "channels" for transmitting electrical energy, wires and cables may seem ordinary, but they are far more complex. Within the conductors, powerful currents surge in real time; on the outside, thick insulation protects them.

Tianhong Cable, a key investment attraction project in Guizhou Province, settled in Huishui County in 2012. The factory occupies nearly 300 mu (approximately 1,000 acres) and is equipped with over 110 pieces of production equipment. Currently, the company primarily produces 19 types of environmentally friendly wires and cables, including those 35kV and below, and specialty cables. The full current they deliver illuminates countless homes.

In crowded places like schools, hospitals, and supermarkets, fire-resistant cables are the lifeline for fire rescue. To address the flammability and heat resistance of ordinary cables, Tianhong Cable utilizes traditional cable production techniques to coat the conductors with specialized materials, developing safer and more durable products.

"This is a mineral fire-resistant cable. Its long-term operating temperature is 90°C, and its short-term operating temperature can be below 250°C. A flame burning at 950°C-1000°C can provide continuous power for over three hours, and its short-term or very short-term operating temperature can reach 1083°C," said technician Wu Zhengsen while introducing the product.

In the production workshop, machinery churns at high speed, with over 80 production lines operating at full capacity. Amidst the roaring sound, workers toil tirelessly through the wire drawing, twisting, insulation, and cabling processes.

Reels of copper coils, each containing over 99% copper, are stretched and tapered by automated wire drawing equipment, from an initial diameter of 8 mm to 1.17 mm. The thinnest reaches 0.12 mm, comparable to a human hair.

The conductor, formed by twisting and intertwining multiple fine copper wires, is encased in mica tape and ceramic silicone rubber tape. During the cabling process, the gaps between the conductors are evenly filled with fiberglass rope or low-smoke, halogen-free tape. Finally, mechanical equipment coats the cables, now covered in layers of protective clothing, with aluminum alloy or copper armor.

After undergoing these multiple steps, the cables have grown from their original thin filaments to thicker, and possess excellent flame retardancy. "In the event of a fire, the cables will neither produce toxic gases nor immediately shut off the power. They will continue to conduct electricity until the copper conductor melts, buying valuable time for escape," said Technical Director Xiao Eryong.

Insulation eccentricity is a key parameter for measuring cable quality, directly impacting its service life and safety. "Generally speaking, the conductor should be located at the center of the insulation layer. Due to process control and material quality, the insulation layer may shift, leading to leakage and wear over extended periods of operation, impacting transmission quality." Wu Zhengsen explained that, through research and development improvements, the eccentricity of medium- and high-voltage products has been reduced to 3%-8%, exceeding the national standard of 15%.

In recent years, Tianhong Cable has achieved industrial application in specialty cables and derivatives, including its independently developed low-smoke, halogen-free, fire-resistant, irradiated wires and cables. Guizhou Tianhong Cable has secured numerous orders for its three fire-resistant cables, a key growth driver. In the first quarter of 2024, orders for fire-resistant cables alone exceeded 12 million yuan.

Adapting to Local Conditions: Improving Aluminum Alloy Cable Processing

Guizhou Province is rich in bauxite resources, offering significant advantages for developing aluminum and aluminum deep processing industries. In 2017, Tianhong Cable decided to focus on the development of aluminum alloy cables, becoming the first company in the province to do so.

During the initial stages of its transformation, Tianhong Cable encountered technical bottlenecks in its production. To address this, in 2019, the company recruited Xiao Eryong, a key technical expert, from an Anhui aluminum alloy cable manufacturer and entrusted him with important tasks.
"The North American aluminum alloy cable market is vast and highly mature. The company hired me not only to overcome the technical challenges of aluminum alloy cables, but also to prepare for export," said Xiao Eryong.
Copper and aluminum are both primary raw materials for wire and cable production, but aluminum is less conductive. Therefore, after numerous refinements and tests, Xiao Eryong determined that, while maintaining comparable conductivity, the aluminum alloy conductor cross-section could be appropriately increased, with the overall cable outer diameter increase limited to 20%.

In recent years, evolving end-use applications have driven market demands for smaller and lighter cables, driving the trend toward lightweight and compact cable products. This is also Tianhong Cable's research goal.

To meet current market demands, Tianhong Cable has leveraged advanced compression technology to increase the fill factor of aluminum alloy cables to 93%, continuously reducing the gaps between individual wires and reducing the outer diameter of aluminum alloy cables.

In the production workshop, each drawn conductor is heated in a high-temperature furnace and then cooled in water. "Annealing is a critical step in the production of aluminum alloy cables. After physical stretching, the conductor may harden and become brittle, reducing its toughness and increasing its resistance. The annealing process realigns the grains within the cable, improving its hardness, strength, toughness, and conductivity, thus providing better conditions for subsequent processing and use," said Wu Zhengsen.

"Aluminum alloy cables with excellent bending properties, deformation resistance, and corrosion resistance can ensure stable performance even under prolonged overloads and overheating," said Xiao Eryong.

Products are the best "spokespersons." As aluminum alloy cable technology matures, sales of similar products at Guizhou Tianhong Cable have continued to rise, gradually becoming a flagship product and currently accounting for over 30% of total production.

Technology empowers cables to connect the vast market

Guizhou Tianhong Cable currently produces nearly 180 kilometers of product daily. In the warehouse, the massive I-spool spools of wire stand out against the cardboard boxes of household electrical wiring. These cables will soon be shipped to customers in Guizhou, Yunnan, Gansu, Hunan, Chongqing, and other regions.

"Our low-voltage and medium-voltage cables are custom-made and produced on demand, with orders exceeding 80 million yuan since 2024," said Wu Zhengsen.

Technological innovation is a core factor driving corporate development. Tianhong Cable boasts two national-level R&D teams, employing over ten top domestic cable R&D experts. The company has established two internationally standardized R&D centers, an international high-tech laboratory, and a wire and cable testing center. The company has been awarded 17 utility model patents and three invention patents.

Xiao Eryong stated that Tianhong Cable prioritizes R&D. Besides leveraging its own teams, it also collaborates with universities for industry-university-research collaborations. For example, the company is developing new energy vehicle cable technology with Harbin Institute of Technology, developing Category V aluminum alloy conductors with Guizhou University, and collaborating on projects with Guizhou Normal University and Guizhou Institute of Technology.

Tianhong Cable also maintains stable partnerships with companies such as China Railway Construction, China Huadian, China Railway Group, and China Huaneng, and is a Tier-1 supplier for State Grid and China Southern Power Grid. Products from Guizhou Tianhong Cable are used in projects such as the Three Gorges Dam, Guiyang North Station, the Guiyang-Huangshan Expressway, Guiyang Longdongbao Airport, and the Guizhou Financial City.

How can one identify the right direction for innovation? Tianhong Cable's answer is market demand. In the province, the company was one of the first to enter the sub-sectors of aluminum alloy cables, rail transit cables, new energy cables, etc., and produced mature products.

In recent years, Tianhong Cable has continuously improved its technology, vigorously promoted structural energy conservation, technical energy conservation, and management energy conservation, and accelerated its transition to a green and low-carbon economy. In particular, it has launched environmentally friendly products such as low-smoke and halogen-free power cables, photovoltaic cables, and cables for new energy vehicles, pioneering a new market for "green cables."

Facing the rapidly developing new energy vehicle industry, Tianhong Cable began planning as early as 2019. "This industry has high requirements for cable flame retardancy, flexibility, and wire diameter. To address this, we have improved our process and replaced rubber with thermoplastic elastomer as a filler, which is more environmentally friendly and safer," said Xiao Eryong.

To date, Tianhong Cable has been recognized as a "National High-tech Enterprise" for nine consecutive years and has been awarded the titles of provincial "Green Factory" (2021), Guizhou Provincial Technology Innovation Demonstration Enterprise (2023), and national "Little Giant" Enterprise for Specialized and Innovative Products (2023). Its aluminum alloy photovoltaic cables are certified by TÜV Rheinland.

Xiao Eryong stated that in the future, Tianhong Cable will continue to strengthen technological innovation, using genuine core technology to produce cables, ensuring product quality while increasing added value. The company will establish itself through excellence and empower its customers through expertise, accelerate transformation and upgrading, and move towards innovation, specialization, and green development, contributing to the development of a new type of industrialization.

Source | Guizhou Daily Editors | Sun Wenhui and Chang Jia
Reviewer | He Xiaofang