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Poringalkuthu Left Bank Extension Hydro Electric Project

PLBE 1 x 16 MW Powerhouse

The Poringalkuthu Left Bank Extension (PLBE) Hydro Electric Project is an additional power generation facility with an installed capacity of 16 MW (1 x 16 MW). It serves as an extension to the existing Poringalkuthu Hydro Electric Project (HEP), which has four Generators of 9 MW each. Both projects are situated along the Chalakudy River basin in the Chalakudy taluk of Thrissur district (Latitude 10º 18’ 45” N, Longitude 76º 38’ 10’ E). The PLBE project utilizes water from the Poringalkuthu Dam which is fed through a fifth penstock pipeline to generate electricity. The power generated from the PLBE Project is fed into the 110KV switchyard for power evacuation to the system grid. The annual generation target of the PLBE project is 100 MU. PLBE powerhouse have ISO 9001:2015 Certification.

Brief History

The foundation stone of the PLBE Powerhouse was laid on November 15, 1994, by Sri. C.V. Padmarajan, the Honorable Minister for Electricity of Kerala. The project costs approximately Rs 41 crores for its successful completion.

The PLBE power station was officially inaugurated on March 20, 1999, by E K Nayanar, the Honorable Chief Minister of Kerala. The powerhouse is equipped with a single vertical shaft Francis Turbine, designed for direct coupling with a 3-phase, 50 Hz, 16 MW generator. The turbine operates with an average head of 165.3 meters. The Turbine and Generator were designed and manufactured by BHEL (Bharat Heavy Electricals Limited).

The Water conducting system of Poringalkuthu Power House consists of Intake, Power Tunnel, Surge Tank, Low-pressure pipelines, Butterfly Valves, and Penstocks. The Intake structure consists of twin concrete wells with an operating platform at the top and a trash rack at the bottom. Two gates operated from the top control water through the intake. The open channel conveys water from the reservoir to the Trash track mouth. From the Intake structure, the water goes through a concrete-lined Power Tunnel driven in rock for a length of 1228 m (4029 feet) with a finished sectional area of 144 sq.ft. The Tunnel has a bed slope of 1 in 200 and a maximum discharge of 34.23m3/sec. and maximum allowed velocity of 2.55 meters per second.

The Power tunnel ends at Surge Tank in the rock of dia 15.5 m (51 feet, 6 inches) and height of 34 m (111 feet) above the floor to even out pressure surges due to load variation. The surge tank is provided to reduce the water hammer pressure in the water-conducting system.

Two low-pressure pipelines 2.4 m (8 feet, 6 inches) in diameter each emerge from the surge tank. A 'Y' piece joint had been provided for further extension of pipe to PLBE. Machine Nos. 1, 2 & 3 receive water from the first LPP and Machine No: 4 of PLB and Machine No. 5 PLBE from the second LPP. The total length of the low-pressure lines is 44.8 m (147 feet) and the thickness of the pipe is 16 mm (5/8 inch). The pipes are taken through a tunnel and the areas outside of the pipes are concreted. The max. velocity allowed through these pipes is 3.236 meters per second.

These two low-pressure pipelines end at Valve house where the Butterfly Valve is situated. The butterfly valve controls the flow of water to the penstock. It consists of a circular ventricular plate, which can rotate about the central axis perpendicular to the pipe axis. When open, it aligns itself in the direction of flow. When closed, it blocks the flow passage completely.

The Penstock starts from the downstream side of the Butterfly valve. Penstock has 1.75 Meters dia, 890 Meters long and is anchored down to the rock by 10 anchors and supported between anchors on masonry supports. The Penstock extends up to the powerhouse and there is a Spherical valve called Main Inlet Valve (MIV) is employed to control the flow of water to the spiral casing. Guide vanes placed just before the turbines regulate the flow of water to the turbine as per the load requirement.

The Generator has a generation voltage of 11 kV and a rated power factor of 0.9 lag. The generated power is fed to the 110 kV Switchyard through an insulated bus duct inside the powerhouse and then through 11 kV underground power cables outside the powerhouse.  An 11 kV/110 kV Generation Transformer (GT) with a capacity of 20 MVA is used to step up the generated 11 kV voltage to 110 kV grid Voltage for transmission.  The power generated is transmitted to the Chalakudy 110 kV grid substation through two 110 kV feeders. Additionally, the third feeder is connected to the Sholyar power station, and the fourth feeder is linked to the Malayatoor 110 kV substation.

In the tail race of the PLBE powerhouse, a Screw Turbine Generator of capacity 11 kW is installed in order to utilize the discharge water of 16 MW generator. 35kW Solar Power Plant is also installed in the powerhouse premises.

Salient Features:

Location with district : Poringalkuthu, Chalakudy, Thrissur District.
Category : Hydro Power Project
Capacity : 16 MW
River : Chalakudy
Dam : Poringalkuthu
Annual Energy Potential :      100 MU

Reservoir :

Catchment Area :  512 Sq. K.M (197.68 Sq. Miles)
Gross Storage : 30.30 MCM
Generation per MCM : 0.389 MU
Design Head : 165.3 Mts.
Full Reservoir level (FRL) : 1391 Ft. (424 M)
Min. Draw Down Level (MDDL) : 1331 Ft. (405.8m)
Design Disch. through Machine : 11.42 M3 /Sec

Date of Commissioning:

Unit – 5 : 20-03-1999
Date of Rennovation: NIL



a) Type : Vertical Fransis
b) Make : BHEL, India
c) Design Net Head : 171.3 Mts. (Max) / 165.3 Mts (Avg)
d) Rated Output :   17    MW 
e) Output Max./ Min : 18.7 MW/ 10.2 MW
f) Normal Speed : 600 RPM
g) Runway speed : 1050 RPM
h) Disc. Through Machine : 11.42 M3/Sec


a) Type : SV 343/76-10
b) Make : BHEL, India
c) Rated Voltage : 11000 V
d) Rated Out put : 17775 KVA
f) Speed : 600 RPM
g) Power Factor : 0.9

3. Generator Transformers

a) Type : ONAF
b) Make : TELK
c) Rated Voltage : 11000/110000 V
d) Rated Out put : 20000 KVA

4. Power Evacuation

a) 110KV POCH1 Poringalkuthu Chalakudy 1  
b) 110KV POCH2 Poringalkuthu Chalakudy 2 
c) 110KV POSH Poringalkuthu Sholayar
d) 110KV POMA Poringalkuthu Malayatoor


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