Formed in 1999, Gujarat Energy Transmission Corporation Limited (GETCO) is among the largest state utilities in the country. Over the years, GETCO has expanded its transmission network in line with the state’s growing power demand and renewable energy capacity needs.
It has been undertaking capacity additions and network improvements to facilitate the integration of upcoming generation capacity in the state. It has proactively taken measures for reactive power management to reduce losses and improve power supply quality, optimisation of feeder length to overcome load diversity, and replacement of ageing and obsolete assets.
Notably, GETCO has adopted state-of-the-art technologies for load forecasting, renewable energy forecasting and demand-side management to enable efficient grid operations. It has also developed various analytical tools for real-time grid operation to minimise the backing down of conventional power stations.
Network growth and performance
GETCO has a transmission network comprising around 71,934 ckt. km of transmission lines and 2,247 substations, as of December 31, 2022. During 2021-22, the transco helped meet a maximum power demand of 21,382 MW. Around 37,694 ckt. km, or 52 per cent, of the utility’s transmission lines are at the 66/33 kV level, followed by 21,563 ckt. km at the 220 kV level, 6,842 ckt. km at the 400 kV level, and 5,835 ckt. km at the 132 kV level. Meanwhile, 2,055 substations – about 91 per cent – are at the 66/33 kV level, 115 substations are at the 220 kV level, 57 substations at the 132 kV level, and the remaining 20 substations at the 400 kV level.
As of March 2022, the company’s transformer capacity stands at 147,151 MVA, having registered a growth of 6.13 per cent over 138,646 MVA in 2020-21. Over the past five years, the company’s transformation capacity has increased at a compound annual growth rate (CAGR) of 7.53 per cent.
GETCO has consistently recorded high system availability of over 99 per cent in the past 18 years. It managed to achieve transmission line availability of 99.66 per cent and substation availability 99.91 per cent during 2021-22. The company’s transmission losses have remained under 4 per cent since 2013-14, and stood at 3.6 per cent in 2021-22.
GETCO’s total revenues for 2021-22 stood at Rs 48.95 billion, compared to Rs 47.15 billion in the previous year, having recorded a year-on-year growth of 3.82 per cent. Its total revenues have increased at a CAGR of 7.05 per cent over the past five years. The utility’s profit before taxes decreased by 1.37 per cent and stood at Rs 18.04 billion during 2021-22, compared to a profit of Rs 18.29 billion in the previous fiscal.
GETCO has been undertaking various initiatives to improve grid supply and build infrastructure under various schemes.
- TASP: For rapid socio-economic development of the tribal communities in Gujarat, it is necessary to supply uninterrupted and quality power by strengthening the power infrastructure in the region. Under the Tribal Area Sub Plan (TASP) scheme, GETCO’s planned investment for 2022-23 was Rs 2 billion. Meanwhile, during 2021-22, GETCO spent Rs 3 billion to build power infrastructure for the development of these areas.
- GEC: Under Phase I of the Green Energy Corridor (GEC) scheme, GETCO identified and approved substations and lines worth Rs 19.62 billion for renewable energy evacuation in the state. With a 40 per cent grant from the Ministry of New and Renewable Energy, and a 40 per cent loan from KfW, Germany, around 92 per cent of the project has been completed, and about six transmission lines are expected to be completed by June 2023. Meanwhile, under GEC Phase II, GETCO will spend around Rs 36.67 billion on development work that is expected to be completed by March 2026.
- Solar park integration projects: GETCO has commissioned the Raghanesda substation to evacuate 600 MW of solar power from the Raghanesda solar park. An additional 100 MW of capacity is expected to be commissioned soon. Further, GETCO has commissioned substations at the Dholera, which will evacuate 300 MW of solar power from Dholera solar park. The remaining 700 MW is expected to be commissioned by December 2025. Moreover, GETCO is expected to complete the Babarzar project for 210 MW of solar power by December 2023.
- Sagarkhedu Sarvangi Vikas Yojna (coastal scheme): Under this scheme, meant to improve grid connectivity in the coastal areas, GETCO constructed new substations and lines while upgrading those that had deteriorated at an investment of Rs 1.88 billion during 2021-22. GETCO’s planned investment under the scheme was Rs 1.88 billion for 2022-23.
- KSY: With the primary aim of supplying power to the agricultural sector during the day, the state government of Gujarat has adopted the KSY scheme at a total cost of Rs 35 billion. GETCO will implement the scheme, covering all 33 districts of the state by constructing extra high voltage (EHV) substations and transmission lines. Around Rs 4 billion was spent in 2020-21, and Rs 10 billion in 2021-22. A further investment of Rs 14 billion was planned for 2022-23.
GETCO has automated 59 substations till date, of which 40 are operated from a remote control centre. With this, one or more substations can be centrally operated from a nearby substation functioning as a master remote control centre. About 14 substations are currently being automated, while 16 more are in the pipeline.
To improve the reliability and availability of power, GETCO has adopted digital substations. It has deployed optical current transformers and merging units in its existing substations. GETCO has completed four pilots with different configurations and modalities at the Jambuva, Asoj, Lunawada and Modasa substations. Based on the experiences and learnings from these projects, the fully digital 220/66 kV Sevaliya substation is planned to be operationalised with 20 bays (seven 220 kV bays and 13 66 kV bays). It is currently at an advanced stage of engineering. Further, GETCO has been deploying gas-insulated switchgear (GIS) and hybrid switchgear, as they are maintenance-free and economical on a life-cycle-cost basis. Five GIS substations each at the 66 kV and 220 kV levels, and six at the 400 kV level have been installed by GETCO. It has also installed five hybrid switchgear substations at the 220 kV level, and one each at the 132 kV and 66 kV levels.
GETCO is increasingly adopting high-capacity conductors as well as high temperature low sag (HTLS) conductors, as they offer 50 per cent more capacity and lower transmission loss levels. It has fully adopted AL59 alloy conductors for the 220 kV and 400 kV levels.
GETCO has successfully adopted ester oil-fuelled 66/11 kV class power transformers. Ester oil has a high flashpoint, safeguarding transformers from catching fire. It has also procured one 220/ 66kV, 100 MVA ICT natural ester-filled transformer as part of a new initiative for EHV applications.
Moreover, GETCO has implemented an integrated asset management system, which is centrally managed by a monitoring system via intranet. Given the growing importance of communication for remote control and monitoring, GETCO has been laying optical ground wire (OPGW) as well. So far, 10,691 km of OPGW has been laid, 1,905 km is under construction, and letter of awards for 7,209 km have been issued. Further, the utility has implemented cybersecurity measures in its IEC 61850-based substation automation systems at the 220/66kV Kamlapur air-insulated switchgear substation and the 220/66kV Metoda GIS.
Other key technologies adopted by the utility include wind forecasting and scheduling, real-time grid visualisation, SF6-insulated compact switchgear with supervisory control and data acquisition at the 11 kV level, and static synchronous compensators (STATCOMs) for dynamic reactive power. GETCO has installed a 220 kV ±120 MVAR STATCOM at its Timbdi substation.
Challenges, future plans and outlook
Like other transcos in the country, GETCO is facing issues pertaining to right of way (RoW), land unavailability and line shifting. To overcome the RoW issue, GETCO is installing HTLS conductors in its existing corridors. The scarcity of land is constraining the installation of new substations. As a result, existing substations need to be upgraded, thus compromising transformation capacity and number of bays. Meanwhile, monopoles and power cables need to be installed at sites where line shifting towers cross with highways or rail tracks, which is expensive.
Notwithstanding these challenges, GETCO has robust future capacity addition plans. It plans to add 28,982 ckt. km of transmission lines and 451 substations between 2023-24 and 2026-27. Further, the transco’s focus is on adopting digital technologies and automation processes, with an eye on enabling ease of operation, retrieval of past data and error-free grid management.
Net, net, GETCO is focusing on building a robust transmission network with adequate capacity at all voltage levels in order to integrate the anticipated renewable energy additions while providing quality and uninterrupted power supply to its consumers.
Based on presentations by B.P Soni, Superintending Engineer (Engineering), GETCO, at a recent Power Line conference