Transmission

Evolution of Transmission Network in Kerala

EHT Power Transmission grid in the state of Kerala came into existence in 1940 at 66kV level in connection with the commissioning of Pallivasal Hydroelectric Project.

66 kV substations at Alappuzha, Mavelikkara, Kothamangalam, Kundara, Kalamassery, Viyyur, Aluva, and Thiruvananthapuram along with the associated 66kV transmission lines were commissioned in 1940 for evacuating power from Pallivasal Hydroelectric Project. For the same 215.6 km of 66kV double circuit lines were constructed by connecting Kothamangalam, Aluva, Pallom, Mavelikkara and Kundara substations and 41.8km of 33kV single circuit lines by connecting Alappuzha and Mavelikkara Substations. Before commissioning the Pallivasal Power House, except Pallivasal-Kothamangalam line, all 66kV lines were test charged in 11kV by using the power generated at Thermal Stations Kollam and Kalamassery.

Consequent to the reorganization of States, the following arrangements were made with Madras State Electricity Board for ensuring supply of power to the transferred area

1. Power was drawn at 66kV from Uppatti for distribution in Kannur, Kuthumunda, Mananthody, Kozhikodu and adjoining areas.

2. Power was drawn at 11kV from Uppatti for distribution in Nilambur

3. Power was drawn at 22kV through the Madukkarai-Palakkad line for distribution in Palakkad, Chittur and adjoining areas.

Kerala supplied power to Madras at 66kV at Thuckalai for distribution in Thuckalai, Nagarcoil and adjoining areas.

At the time of formation of Kerala state, the load in the Malabar and Palakkad area was about 6000kW. Madras had to meet this until Kerala was in apposition to give supply from its grid till 1960 and the demand at the time of 1960 was 10,000kW.

On the other hand the load in the southern area of Travancore – Cochin transferred to Madras was about 1700kW at the time of state reorganization and continued till 1960 until Madras completed their arrangements for feeding and demand hiked to 4000kW.

Part of Chenkotta Taluk merged with Madras was switched to the Madras grid from Travancore-Cochin grid from the date of state reorganization.

During the summer of 1957, there was acute shortage of power in the Madras grid due to water scarcity and the power cut imposed in Malabar area. The Board arranged to supply 5000kW from Kerala grid to Madras at Chenkotta on temporary basis and power cut exempted from Madras grid and in turn Malabar area and the same continued since after the crisis.Due to the increased power crisis in the Madras Grid, as a relief, the load to the Palakkad and adjoining area also shifted to the Kerala grid.

Along with the construction of Transmission lines and Substations, deployment of communication systems was also started. Carrier Communication between Sengulam, Pallivasal, Aluva and Poringalkuthu was established on a temporary basis on 05.01.1957. The installation of the carrier communication equipment in all the stations was completed during the year 1958-59. The system has been in regular use from September-October 1958.

 

The construction work of 110kV Substation at Sengulam was completed by 06/1958 and the generating units together with the transformers energized on 12.07.1958. The station was put into commercial operation from 26.07.1958. This marked the commencement of operation of 110kV Grid in Kerala. Also 66kV Substations at Pallom and Kundara were upgraded to 110kV.

With the completion of the 66kV transmission line from Viyyur to Palakkad and the temporary 66kV Substation at Palakkad, the load of about 1000kW in Palakkad was transferred from the Madras grid to Kerala by 16.03.1958.

The construction of 110kV transmission double circuit lines from Chalakudy to Shoranur and from Shoranur to Kozhikodu was commissioned during 1962-63. Construction of the Peerumedu -Pamba -Kakki 66kV line and 66kV Substation at Kakki was commissioned during 1962-63. The 110kV substations at Aluva and Chalakudy and 66kV substations at Shornur were commissioned during 1964-65.

The 110kV temporary Inter state link with Mysore grid was completed by 1965-66 and the line charged at 110kV. Supply from Mysore grid was received at Kannur substation where one 5 MVA 110/11kV transformer was commissioned. One circuit of the 110kV double circuit line between Chalakudy and Kozhikkode was commissioned during 1966-67

 

One circuit of the Moozhiyar - Pallom section of the 220kV double circuit from Moozhiyar to Pallom then to Kalamassery line was completed during this year. A 60 MVA 220/110kV Transformer was also temporarily commissioned at Pallom substation. The commissioning of Sabarigiri Project elevated Kerala to a power-surplus state in 1966.

 

The 220 kV grid came into existence in connection with the commissioning of Sabarigiri Hydroelectric Project and Pallom 220kV Substation was the first 220 kV substation in Kerala, which was commissioned in 1966. After a few months, the 220kV Substation, Kalamassery was also commissioned.The power was also supplied to Tamil Nadu through the 220kV Sabarigiri - Theni Inter-state line from 30.01.1969. The 22kV supply drawn from Tamilnadu through the Walayar point for the distribution in Palakkad was discontinued from June 1968.

The 110kV lines from Poringalkuthu power station to Kalamassery, Kalamassery to FACT Aluva and 66kV Kundara -Quilon line were commissioned and 110kV substation Kanhangad, 66kV substations Neyyattinkara and Cherthala were also commissioned during 1968-69.

Kozhikode to Vadakara stretch of 110kV Kozhikode- Kannur line and Vadakara 110kV substation commissioned in April 1970 and balance portion commissioned by August 1970 and thereby the power purchase from Mysore was stopped. 66kV Punalur - Pathanamthitta line and 66kV Pathanamthitta substations were completed during the year 1969-70. 66kV Substations Kollam and Karukutty were commissioned during 1970-71.

With the comfortable power generation capability after the commissioning of Idukki Hydro Electric Project, more attention was given to expand the transmission network especially 220kV and 110kV. 220kV Idukki-Kalamassery and Idukki- Pallom feeders were commissioned during 1976-77. 220kV Substation Edamon was commissioned during 1978-79. 66kV Substations Vyttila and Paruthippara were upgraded to 110kV .

By the end of 1981, there were 4 numbers of 220kV substations 887.33 ckt.kms of lines , 19 numbers of 110k Substations and 1577.34 ckt.km of line, and 73 numbers of 66kV substations and 2123.063 ckt. Km of lines.

During 1988-89, 220kV substations at Pothencode, Trivandrum and 220kV Edamon-Trivandrum lines with a circuit kilometer of 94 were commissioned which enhanced the power position of Capital city.

 

During 1989-90, Nallalam Kozhikode substation was enhanced to 220kV and also commissioned the 220kV Idukki-Udumalpet SC interstate feeder of ckt length 83.225km.

Considering the peculiar geographical shape of the State, a 400 kV backbone transmission network from northern part of the State to the southern part was proposed with intermediate substations at 220 kV and 110 kV voltage levels to cater to the load requirement of various load centers.

Madakkathara is the first 400 kV substation in Kerala owned by KSEB, which was commissioned on 30.01.1993, which was connected to the interstate transmission network at 400 kV level.

Subsequently 400 kV Substations at Pallippuram, Areekode, Palakkad, Kochi East and Kottayam commissioned.

The Kerala grid is presently connected to the national grid mainly through 400 kV double circuit lines viz. (1) Udumalpett – Elapully, (2) Thirunelveli – Pallippuram (Trivandrum), (3) Mysore – Areekode, (4) Thirunelveli – Kochin East and 320kV HVDC Pugalur-Thrissur line.

Transgrid 2.0 is a futuristic project being implemented by KSEBL aiming strengthening of the Transmission infrastructure for meeting the future energy demand of the state. It is planned to be implemented in two stages. The first phase of the project was planned for execution during 2017-2022 and second phase for 2019-2024. Phase I include construction of 12 substations out of which 4 are Air Insulated and remaining are Gas Insulated and 2084 km of EHT lines. All the 12 substations under Phase 1, including one 400kV Substation (Kottayam) and eleven 220 kV substations (Manjeri, Chalakudy, Kothamangalam, Aluva, Kaloor, Kunnamangalam, Chithirapuram, Ettumanoor, Vizhinjam, Thalassery, Kunnamkulam) and 1467 circuit km of EHT lines which include 179 circuit km of 400 kV lines have been completed so far.

Over the 66 years, the Transmission network of KSEBL has been established over the entire area of the state, which include networks of voltage level varying from 33 kV to 400 kV, having 426 substations and 18612 kms of lines.