Thursday, May 29, 2008

Terengganu Hydro-Electric Project

Terengganu Hydro-Electric Project

Date of Issue: 1987-07-13
Denominations: 20 cents, $1.00
Stamp Size: 31.5 mm x 48.0 mm
Paper: SPM watermarked phosphor coated
Printing Process: Lithography
Printer: Security Printers (M) Sdn. Bhd., Petaling Jaya, Malaysia
Sheet Composition: 50 stamps
Designer: Kathy Design, Kuala Lumpur

Stamps in the Series:

First Day Cover:

The Terengganu Hydro-Electric Project is located in the State of Terengganu, Malaysia and comprises twin diversion tunnels, a main dam, a free overflow spillway, an inlet structure leading to 4 steel-lined tunnels, a conventional surface power station housing 4 generating units of 100 MW each, and 8 saddle dams. The main dam is a rockfill structure with a height of about 150 m. All the saddle dams are of earthfill construction. The total volume of fill for these dams is 25.7 million m.

From a catchment area of 260,000 ha. the dam impounds 13,600,000,000 cu. Meters of water at normal full supply level, of which 7,400,000,000 cu. meters are utilized as live storage. The surface area at full supply level is 36,900 ha.

Twin tunnels 14 m in diameter diverted the river of the dam. One 1.75 m hollow cone valve and a butterfly valve provided in one of the diversion tunnels discharged riparian flows during the filling of the reservoir. The generating facilities consist of four machines with a total installed capacity of 400 MW and produce an average energy output of 1,600 million units per annum.

The power station has four generating units made up of Francis type turbines vertically coupled to air-cooled generators. The units are housed in a conventional building which includes repair bay, control room, workshops, office and storage facilities.

The four turbines have an output of 100 MW each at a rated head of 120 m and the generators are rated 112 MWA/0.9 PF 50 Hz. The generators’ output is connected to three-phase 13.8/275 kV/112 MVA oil-cooled transformers, through the substation and then by 275 kV transmission lines to the system network.

A total volume of 17,000,000 cubic meters of fill material was used for the construction of the Kenyir Dam over a period of two and a half years.

The core material of weathered granitic clay was obtained from burrow areas located 1 to 2km upstream of the site. It was placed in the central zone of the dam to act as the impervious zone.
The rockfill for the dam, obtained from a borrow area located 2km upstream of the site is granite which also extends throughout the entire foundation area. Rock from the borrow area was placed on the outermost zones of the dam. Filter material consisting of fine crushed rock and river sand was placed in between the rockfill and core zones to serve as transition material.

The upsteam cofferdam was built to a height of some 60m to pass flood flows through the diversion works during the construction period. This cofferdam was subsequently incorporated into the main dam.

There are 8 saddles along the catchment boundary of the Terengganu River Basin which are below the proposed maximum water level of the reservoir.

To prevent overflow or leakage through these saddles, an embankment with the same crest elevation as the main dam is constructed in each of these saddles. They vary in height from 19 m to 45 m. all of the saddle dams are homogeneous earthfill embankments and have a similar cross-section which provides for a cut-off to groutable rock and a vertical chimney drain.

The spillway is located on the right bank of the dam abutment. The spillway is an ungated, ogee-type structure with a 140 m wide crest, leading to a 50 m wide chute which terminates in the river channel.

The spillway is capable of attenuating the incoming probable maximum flood to a maximum discharge of 7,000 cubic meters with a corresponding rise of the reservoir level of 8 m.

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