Switchgear and substations are crucial components of power systems. Electrical devices such as switches, fuses, circuit breakers and relays that help to monitor, control, protect and isolate the grid are collectively referred to as switchgear. This equipment interrupts the flow of current to protect the grid from damage during electrical surges as well as helps to de-energise electrical infrastructure for safe testing and maintenance. Meanwhile, substations help regulate the electrical voltage (step up or step down) as per the requirements of utilities and consumers. The demand for switchgear and substations grows in tandem with the expansion of the transmission and distribution (T&D) network. Given that growth in the transmission segment is expected to increase due to the need to create new links and strengthen the existing ones to evacuate large-scale renewables, the demand for switchgear and substations will also witness a surge. Likewise, implementation of new government schemes in the distribution segment such as the Revamped Distribution Sector Scheme with an outlay of Rs 3.04 trillion will lead to network modernisation and upgradation, further driving the demand for switchgear and substations.
Power Line presents an overview of the switchgear and substation market, recent developments, key technology trends and the way forward…
Growth in substation capacity
Transmission substations can be broadly categorised into two, depending upon their voltage. In the Indian context, high voltage direct current (HVDC) substations include ±800 kV, ±500 kV and ±320 kV, while alternating current (AC) substations range from 132 kV to 765 kV (though some state transcos have substation capacity at 66 kV too, for instance, GETCO, KPTCL, etc.). In the case of distribution, substation voltages are typically lower at 33 kV and below.
As per the Central Electricity Authority (CEA), AC substation capacity stood at 1,078 GVA as of April 2022. About 39 per cent of this capacity is at the 220 kV level, 37 per cent at the 400 kV level and 24 per cent at the 765 kV level. Between 2015-16 and 2021-22, AC substation capacity has grown at a compound annual growth rate (CAGR) of 8.8 per cent. HVDC substation capacity stood at 33,500 MW, of which the majority (54 per cent) is at the ±800 kV level, 40 per cent is at the ±500 kV level and the remaining (6 per cent) is at the ±320 kV level. Between 2015-16 and 2021-22, HVDC substation capacity has grown at a CAGR of 14.3 per cent. Meanwhile, in the distribution segment, 730-740 GVA of transformer capacity was operational as of March 2021, at the 33 kV level and below, across 40 utilities in the country. Between 2016-17 and 2020-21, transformer capacity has grown at a CAGR of 6 per cent.
Switchgear market
As per IEEMA (Indian Electrical and Electronics Manufacturers’ Association), the switchgear industry recorded a contraction of 3.2 per cent in 2020-21 and 1 per cent in 2019-20 as against a growth of 6.4 per cent in 2018-19. This was mainly due to the impact of Covid-19, on demand from key consumer segments.
The market for switchgear is categorised into three segments, based on the load-bearing capacity – low voltage (LV), medium voltage (MV) and high voltage (HV). The LV switchgear segment comprises switchgear rated up to 1 kV, the MV segment consists of switchgear rated up to 33 kV and the HV segment comprises such devices rated at 66 kV and above. The key consumer segments of LV switchgear include distribution utilities, industries, residential and commercial buildings, and agricultural consumers. Common LV switchgear devices include air circuit breakers, moulded case circuit breakers, motor protection circuit breakers, miniature circuit breakers, residual current devices, switch fuse and fuse switch units, high rupturing capacity fuses, thermal overload and protection relays, contactors, starters, distribution boards and switches.
MV and HV switchgear are often grouped together, owing to their similar usage and applications in power systems. Transmission and generation utilities are the key consumers of MV and HV switchgear. Depending on the insulating medium, HV switchgear are classified into three major types – air-insulated switchgear (AIS), gas-insulated switchgear (GIS) and hybrid switchgear. Substations equipped with these are also classified accordingly, that is, AIS substations, GIS substations and hybrid substations. The demand for HV switchgear took a greater hit vis-à-vis LV switchgear in the past two years, with the market size for HV switchgear declining by 11.7 per cent in 2020-21 and 18.6 per cent in 2019-20. Meanwhile, the market size for LV switchgear recorded a contraction of 1.8 per cent and a growth of 3.3 per cent in the respective years. However, the demand for HV switchgear has witnessed a surge in 2021-22, with the market witnessing a growth of over 70 per cent during April-December 2021 with T&D utilities’ plans to expand network.
Technology trends
In view of the growing renewable energy capacity, switchgear has become pivotal in ensuring that networks operate in a synchronous manner with minimum faults. Industry players are constantly developing different kinds of switchgear that are compact, cost effective and require low maintenance.
The growing use of supervisory control and data acquisition has increased the demand for intelligent switchgear, which have built-in protection and control intelligent electronic devices (IEDs) in their switchgear solutions. These new IEDs, combined with the latest information and communication technologies, form a base for enhanced protection, control and monitoring. Intelligent switchgear can connect with the internet and provide comprehensive monitoring and protection functions, as well as measure all electrical parameters in real time. Intelligent switchgear can significantly enhance the efficiency and reliability of the grid and help utilities avoid blackouts and equipment failures.
Substation technologies have also evolved considerably to meet the emerging requirements of utilities and adapt to the changing grid. New designs and features have been driven by considerations such as space optimisation, lower costs, greater asset life, enhanced safety and reduced failure rates of equipment. Conventionally, utilities installed AIS, which use air for insulation between various live parts. A key trend is the growing installation of GIS and hybrid substations in place of conventional AIS substations as Indian utilities grapple with right-of-way and land acquisition issues. In addition, digital substations are gaining traction across utilities as digitalisation enables utilities to identify, prevent and rectify faults through the use of sensors and IEDs. Further, the deployment of the IEC 61850 protocol has provided seamless communication and integration between IEDs. In addition, the application of process bus architecture in digital substations helps add flexibility by enabling digital devices to communicate directly with each other. Process bus also allows for replacement of bulky copper wiring with optic fibre, making digital substations more compact and safer than conventional substations. In December 2020, Powergrid commissioned India’s first 400 kV digital substation based on IEC 61850 process bus at Malerkotla, Punjab. Further, the pandemic has accelerated the need to automate and digitalise power systems and equipment. T&D utilities have increasingly realised the importance of unmanned substations and remote operations and maintenance of assets with local/national lockdowns in the past two years. Consequently, substation automation and remote monitoring solutions are gaining traction.
The way forward
The proper functioning of switchgear and substation equipment is crucial for the health of T&D networks. It is, therefore, essential for utilities to carry out regular testing and maintenance of this equipment. In this respect, utilities and manufacturers can take cues from various guidelines issued by the CEA. For instance, in March 2022, the CEA notified the Guidelines for the Type Tests for Major Equipment in Power Sector as well as Guidelines for Model Quality Assurance Plan for Major Equipment in Power Sector in March 2022.
Going forward, the switchgear and substation segment is expected to witness robust growth driven by the pipeline of transmission projects under the Green Energy Corridors and other government programmes as well as various distribution system strengthening schemes. In addition, ageing grid assets would require upgradation with advanced switchgear and substation solutions. In terms of technology, digitalisation and automation are expected to gain prominence in the near future. N