Substations and switchgear systems are evolving beyond their conventional role as passive grid assets to emerge as intelligent, automated and highly adaptive components of modern power networks. Growing renewable energy integration, space constraints in urban areas, rising reliability expectations and the growing focus on sustainability are driving utilities to adopt new technologies across transmission and distribution infrastructure. Power Line presents an overview of some of the key emerging technologies shaping the next phase of substation and switchgear development in India…
Substations
Smart and digital substations
Smart substations incorporate digital protection systems, advanced switchgear, intelligent electronic devices (IEDs), microprocessor-based relays and data-driven monitoring platforms to automate critical grid operations and improve operational efficiency. Unlike conventional substations designed for one-way power flow, smart substations support dynamic multi-source power routing, enabling better integration of renewable energy and distributed resources.
Digital substations are emerging as a key component of this transition, using IEC 61850-based communication systems, fibre optic networks and process bus architecture to replace conventional hardwired systems, enable faster data exchange, improve operational visibility and reduce maintenance requirements. In in 2024-25, Power Grid Corporation of India Limited commissioned a 765 kV digital substation at Navsari, Gujarat, the world’s first digital substation at this voltage level. The extra-high voltage substation leverages fibre-optic based digital technology for remote monitoring from anywhere, even outside India, thereby enhancing grid stability, resilience and reducing risk of malfunction.Another key trend is the development of self-healing grid capabilities through advanced automation, SCADA integration and real-time monitoring systems. Technologies such as fault location, isolation and service restoration enable rapid fault detection, automatic isolation of affected sections and restoration of power supply through automated switching operations, thus reducing outage duration and improving grid reliability
As substations become increasingly digital and interconnected, cybersecurity-first design is emerging as a critical requirement in modern grid infrastructure. Utilities are integrating secure communication protocols, network segmentation, intrusion detection systems and IEC 62351-based cybersecurity frameworks into substation automation architecture to protect operational technology (OT) networks from cyberthreats.
Underground gas-insulated substations
Underground gas-insulated substations (GIS) are gaining traction in urban transmission networks due to their compact footprint, high reliability and suitability for space-constrained areas. Utilities are deploying these substations in metro rail systems, smart cities, commercial districts and critical infrastructure corridors where conventional air-insulated substations (AIS) are not feasible due to land and right-of-way constraints.
The technology uses compact gas-insulated equipment enclosed within sealed metallic chambers, enabling significant space savings compared to AIS-based systems. Underground GIS substations are typically equipped with advanced ventilation, thermal management, digital protection and automation systems to ensure reliable operation under confined conditions.
Tata Power has operationalised India’s first underground submersible substation in Mumbai, with the model now being scaled across flood-prone urban pockets to enhance resilience and optimise space. The design enables safe operation of electrical equipment even in waterlogged conditions by using sealed, waterproof infrastructure and underground installation suited for dense urban distribution networks.
Modular, mobile and prefabricated substations
Modular, mobile and prefabricated substations are emerging as fast-deployment solutions for utilities, addressing grid expansion, temporary power requirements and emergency restoration needs. These substations are factory-assembled and pre-engineered, reducing on-site civil works, installation timelines and project execution risks compared to conventional substations.
Prefabricated substations integrate transformers, GIS or hybrid switchgear, protection and control systems, SCADA infrastructure and auxiliary equipment within compact containerised or skid-mounted modules. Their plug-and-play design enables faster transportation, installation and commissioning, while improving quality control through factory testing.
Mobile substations, typically mounted on trailers or transportable platforms, are increasingly being used for emergency restoration, planned maintenance and temporary load support. Utilities are also deploying modular substations across renewable energy projects, industrial facilities, metro rail systems, data centres and remote load centres requiring quick grid connectivity.
Renewable-centric substations
Renewable-centric substations are emerging as a key component of modern power systems, enabling the integration, stabilisation and evacuation of power generated from solar, wind, hydro and biomass projects. These substations collect variable renewable power, manage AC/DC conversion and step up low-voltage generation for long-distance transmission through high-capacity transformers. Advanced technologies such as static synchronous compensators (STATCOMs), static VAR compensators, battery energy storage systems, harmonic filters and grid synchronisation systems are increasingly being deployed to maintain voltage stability, frequency control and power quality. Hybrid renewable substations integrating multiple renewable sources and storage systems are also gaining traction owing to their ability to improve transmission corridor utilisation, grid balancing and operational reliability.
Switchgear
Hybrid switchgear
Hybrid switchgear combines the features of AIS and GIS within a single modular system, offering a balance between space efficiency, reliability and cost effictiveness. In a hybrid configuration, critical components such as circuit breakers, disconnectors and earthing switches are enclosed within a gas-insulated chamber, while external busbar connections remain air insulated.
The technology is gaining traction as utilities seek compact and flexible substation solutions without the higher costs associated with fully GIS-based systems. Compared to conventional AIS substations, hybrid switchgear requires significantly less space, making it suitable for urban substations, industrial facilities and expansion projects with land constraints. Hybrid switchgear also offers improved operational reliability and lower maintenance requirements, as sealed gas-insulated components are protected from dust, moisture and pollution.
Sustainable SF6-free switchgear
Sustainable SF6-free switchgear technologies use alternative insulating mediums such as dry air, clean air, vacuum interruption systems, solid insulation and low-global-warming-potential gas mixtures in place of sulphur hexafluoride (SF6).
These technologies are designed to provide insulation, arc interruption and operational reliability comparable to conventional SF6-based equipment while reducing greenhouse gas emissions and environmental risks. Vacuum interruption technology is increasingly being used for medium- and high-voltage applications due to its compact design, low maintenance requirements and longer service life. Dry air and clean air insulated systems use natural atmospheric gases for insulation, eliminating the need for greenhouse gas-based alternatives.
The Central Electricity Authority in its “Green GIS Technology in Indian Grid” report recommended a gradual transition to SF6-free gas insulated switchgear through a structured approach involving pilot projects at lower voltage levels, technology validation and capacity building. It also highlights the need for indigenous manufacturing, testing infrastructure and standardisation to reduce import dependence and enable long-term adoption of green GIS technologies in the Indian power transmission sector.
Intelligent and digital switchgear technologies
Utilities are deploying smart and IoT-enabled switchgear integrated with IEDs, wireless sensors and advanced communication systems to enable real-time monitoring, remote diagnostics and automated control functions.
Condition monitoring-enabled switchgear is gaining traction as utilities shift towards predictive and condition-based maintenance practices. Advanced sensors and analytics platforms help monitor parameters such as temperature, insulation condition, gas pressure and partial discharge activity, enabling early fault detection and reducing unplanned outages. AI-enabled predictive maintenance systems are further enhancing asset management by analysing operational data to predict equipment degradation and optimise maintenance schedules.
Remote-operated and unmanned switchgear systems are also being increasingly deployed across modern substations, renewable energy projects and critical infrastructure networks to improve operational safety and reduce manual intervention. In parallel, digital twin-enabled switchgear solutions are emerging as an advanced asset management tool, allowing utilities to create virtual models of physical equipment for performance analysis, simulation and lifecycle optimisation.
Another emerging trend is the development of virtualised or software-defined substations, where protection, automation and control functions are increasingly being shifted from dedicated hardware devices to software-based platforms operating on virtualised computing environments. Enabled by IEC 61850-based communication architecture, these substations reduce dependence on physical equipment, simplify maintenance and improve scalability while supporting faster deployment of digital grid applications and advanced analytics.
Conclusion
The evolution of substations and switchgear technologies is reshaping modern power networks with higher reliability, automation, sustainability and operational flexibility. Substations are evolving into renewable-ready and energy storage-integrated systems capable of supporting multi-directional power flows, real-time energy balancing and advanced grid management functions.
Technologies such as smart substations, underground GIS, modular infrastructure, SF6-free switchgear and intelligent digital systems are helping utilities address space constraints, improve grid resilience and support faster project execution. At the same time, AI-enabled monitoring, predictive maintenance platforms and advanced protection systems are improving operational efficiency and asset reliability. The substation is no longer just a point where electricity changes voltage. It is becoming a control centre expected to manage renewables, storage, automation and future energy demands simultaneously.
Aastha Sharma
