The demand for advanced cables and conductors is growing rapidly. As power networks become more complex and renewable integration expands, cable technology is playing a crucial role in ensuring efficient, reliable and sustainable energy transmission. In recent years, the cable and conductor industry has witnessed remarkable innovations, ranging from high-voltage direct current (HVDC) cables to high-temperature superconductors (HTS), aimed at delivering greater efficiency and resilience. Meanwhile, submarine cables are expanding renewable energy transmission by connecting offshore installations to mainland grids, whereas smart cables equipped with sensors and internet of things (IoT) capabilities are transforming traditional networks into intelligent, self-monitoring systems. These advancements not only enhance grid performance but also support the transition to cleaner and smarter power infrastructure.
HVDC, EHV XLPE and ABC cables
HVDC systems are critical assets within high-voltage electricity transmission networks. Extruded HVDC cables and systems have witnessed significant advancements in recent years. These cables use cross-linked polyethylene (XLPE) insulation as an alternative to oil-or mass-impregnated cables. Voltage levels in the range of 320-640 kV are now available, and as suppliers and transmission service operators gain operational experience, the maturity and technology readiness levels continue to increase.
Growing urbanisation and limited land availability have made it difficult for utilities to build new overhead transmission lines, with right-of-way (RoW) issues often delaying projects. As a result, utilities are increasingly deploying EHV XLPE cables for underground transmission. However, XLPE cables at extra-high voltage are suitable only for limited lengths, as they require multiple joints and terminations, which are prone to failure and can result in system outages. For applications requiring high current over short distances, gas insulated lines offer a reliable alternative due to their superior thermal and operational performance. India has domestic manufacturing capabilities for XLPE cables up to the 400 kV level, supporting their wider adoption across urban transmission networks.
In the distribution segment, aerial bunched cables (ABCs) are increasingly being deployed by utilities. As compared to conventional bare conductors in overhead distribution systems, ABCs provide more safety, reliability and system economy, reduce power losses, and entail lower installation and operations and maintenance (O&M) costs. They are ideal for rural distribution as well as for installations in difficult terrain such as hilly, forest and coastal areas.
HTLS and HTS conductors
High temperature low-sag (HTLS) conductors are rapidly emerging as a key solution for augmenting transmission capacity without any major structural upgrades. As compared to conventional aluminium conductor steel reinforced (ACSR) conductors of the same diameter, HTLS technologies can operate at significantly higher temperatures while exhibiting much lower thermal elongation. This allows utilities to uprate existing lines simply by replacing ACSR with HTLS conductors while retaining the same RoW.
Meanwhile, high-temperature superconducting (HTS) cables offer near-zero electrical resistance and can carry substantially higher power over long distances. Owing to their light weight and more compact design, HTS cables are particularly suited for space-constrained urban environments. HTLS conductors are broadly categorised into four main types:
- Aluminium conductor composite core (ACCC): These conductors consist of a carbon composite core and trapezoidal aluminium strands. ACCC conductors deliver higher power transfer capacity and lower sag at elevated operating temperatures, along with reduced line losses. Developed by CTC Global, they are widely adopted for their thermal stability, mechanical strength and energy efficiency.
- Aluminium conductor steel supported (ACSS): Comprising annealed aluminium wires and a high-tensile galfan-coated steel core, ACSS conductors are designed for continuous high-temperature operation. They offer lower electrical losses and are easy to install, making them ideal for uprating existing lines.
- Super thermal aluminium conductor invar reinforced (STACIR): Manufactured using aluminium–zirconium alloy strands around an invar steel core, STACIR conductors provide substantially higher power transfer capabilities, although with relatively higher losses compared to other HTLS options.
- Gap-type thermal-resistant alloy ACSR (gap conductors): Featuring a heat-resistant grease-filled gap between the steel core and aluminium layer, these conductors minimise friction, prevent corrosion and improve thermal performance.
Indian manufacturers are also advancing HTLS technologies. APAR Industries has developed high-performance HTLS conductors and twisted-pair designs suited for high-tension and challenging environmental conditions. The company’s POWR-ZAD conductor, with its Z-shaped interlocked wires, enhances aerodynamics and mechanical reliability, helping mitigate the risk of line collapse in extreme weather conditions and enabling longer spans with reduced sag.
Cables for renewable energy evacuation
As renewable energy generation accelerates, the transmission sector is encountering new technical and operational challenges. Offshore wind farms, large solar parks and hydropower stations all require specialised cables.
A range of new cable technologies has emerged to meet these requirements. Solar cables, for instance, are gaining significant traction in the Indian market. Designed for the safe and efficient transfer of energy from solar panels to inverters, these cables serve as critical connectors within a solar installation. They are engineered to endure harsh outdoor conditions. Their construction using high-quality, weather-resistant materials ensures long-term reliability and safety. By maintaining stable power flow and reducing transmission losses, modern solar cables also enhance system efficiency.
While offshore wind projects present significant opportunities, developing transmission systems for these installations remains challenging. Unlike onshore developments, offshore wind farms cannot rely on existing transmission corridors. They require dedicated subsea cables, offshore substations and HVDC or HVAC systems to effectively evacuate power to the mainland. Submarine transmission lines – high-voltage cables laid underwater – are essential for linking offshore wind farms, islands and remote regions to the national grid.
Most long-distance subsea links use HVDC submarine cables to overcome the distance and capacitance limitations of AC systems. Notable examples include the proposed India–Sri Lanka interconnection involving a 285 km HVDC link with around 50 km of submarine cable through the Palk Strait. Another major project is the planned ±320 kV HVDC link from Paradip (Odisha) to Port Blair (Andaman & Nicobar Islands), spanning roughly 1,150 km under the Bay of Bengal. Scheduled for commissioning by 2029–30, it will be India’s first 250 MW HVDC submarine transmission system, designed to reliably power the remote Andaman Islands.
Integration of smart technology
The deployment of sensors and communication technologies has led to the development of smart cables, capable of advanced monitoring, diagnostics and data-driven decision-making. With the integration of IoT technology, smart cables can communicate directly with grid management systems. This connectivity allows them to automatically adjust transmission capacity, reduce overload risks and enhance energy storage coordination across decentralised networks. Smart cables continuously monitor their operating conditions, collecting valuable real-time data on performance, temperature and electrical behaviour. Fibre optic sensors embedded along the cable length enable precise temperature monitoring, helping operators detect overheating and prevent failures. In addition, smart cables are equipped with sensors that measure mechanical strain and vibration, alerting maintenance teams to potential damage or structural stress. Another key feature is partial discharge monitoring, which helps identify early signs of insulation degradation, allowing utilities to take corrective action before a critical failure occurs.
One of the most significant developments is the integration of artificial intelligence (AI)-powered monitoring systems within cable networks. These intelligent systems enable utilities to predict and prevent failures, optimise power transmission and extend the operational lifespan of cables while simultaneously reducing O&M costs.
Another technology is dynamic line rating (DLR), which adjusts conductor capacity based on real-time weather conditions. Since wind speed significantly influences conductor cooling, real-time monitoring can unlock 30–40 per cent additional line capacity, as seen in global deployments. While not a substitute for system augmentation, DLR offers a cost-effective solution for immediate congestion relief. India’s first DLR project has been implemented on POWERGRID’s Tuticorin–Madurai 400 kV line in Tamil Nadu. The project deploys a real-time, AI-based approach to improve renewable integration, optimise grid assets and enhance operational reliability.
Other technologies
A key advancement is the insulated cross arm (ICA), which enables upgrades to existing corridors by reducing insulator swing and eliminating the need for taller towers. ICAs significantly improve ground clearance and help address RoW limitations, especially when combined with HTLS conductors. Their application has been demonstrated in Kerala and Telangana, where corridor width and ground clearance were successfully optimised. Further, photonic coating technologies aim to reduce conductor temperature by enhancing thermal radiation and reducing heat absorption, thus marginally increasing line capacity.At the system level, India is progressing toward 1,200 kV ultra-high voltage alternating current corridors, which deliver high power intensity and lower losses, supporting future bulk power movement.
Conclusion
The cable and conductor technology is undergoing rapid and transformative advancement, driven by the growing demand for efficient, reliable and sustainable energy transmission systems. As power networks evolve, the industry is increasingly focus ed on enhancing performance, reducing energy losses and integrating smart technologies.
As the energy demand continues to rise, the importance of innovative cable and conductor technologies will also increase. Overall, these advancements are essential for ensuring reliable, efficient and environmentally responsible electricity distribution, particularly as renewable energy integration and urbanisation accelerate.
