Sanjen
Sanjen Hydroelectric Project utilizes the tail water from the Sanjen (Upper) Hydroelectric Project and therefore is a cascade run-of-river scheme. The whole scheme is divided into three work sites, viz.Headworks Site that covers Chhupchhung feeder system, spillway, intake/forabay and pressure conduit, Underground Works that covers headrace tunnel, rocktrap, surge tank, penstock shaft (inclined and horizontal) and construction adits, and Powerhouse Site that covers powerhouse structure, tailrace and switchyard.
The headworks site is located at Simbu Village of Chilime VDC. The headworks consist of overflow spillway, intake/forebay of size 80m long and 30m wide, a 115m long low pressure conduit leading to headrace tunnel portal and complete Chhupchhung intake and feeder system.
Headrace tunnel is 3630m long, inverted D shape of excavated section 3.5m x 3.75m and will be partly unlined, partly shotcrete lined and partly concrete lined. Surge tank is restricted-orifice type of height 51m and diameter 5.5 m. Penstock shaft (inclined and horizontal) is 1030m long and underground. Surface powerhouse is located at Chilime Village of Chilime VDC. Powerhouse will accommodate three units of vertical axis Pelton turbines of capacity 15 MW each and three units of 3-phase synchronous AC generators of capacity 16.85 MVA each. Three numbers of tailrace pits joined at tailrace manifold will discharge the tail water to the approach canal of existing Chilime Hydropower Plant. Excess water will be discharged into Chilime River. Surface switchyard is located adjacent to the powerhouse complex.
Generated power from Sanjen Hydroelectric Project will be evacuated through a 2km long 132 kV double circuit transmission line to connect from SHEP powerhouse to the proposed Chilime Hub of NEA and then to the national grid via 220 kV double circuit line up to Trishuli 3B hub of NEA.
Salient Features
| Location | Chilime V.D.C. of Rasuwa district. |
| Type of Project | Cascade Run-of-river |
| Hydrology | 202 km2 |
| Catchment area (Dam site) | 2.4 m3/s |
| 90% dependable flow | 11.57 m3/s(including Chhupchhung flow) |
| Design flow | (Q40) |
| Design flow from Chhupchhung | 0.50 m3/s |
| Geology | |
| Rock Type | Medium grade metamorphosed schist and quartzite |
| Head | |
| Gross | 442.0 m |
| Net | 433 m |
| Headworks | |
| Intake Type | Off take from Tail Water of Upper Power Plant |
| Head Pond (Forebay) | 10 min. |
| Headrace Tunnel | |
| Length | 3630 m |
| Section | 3.5 m (w) x 3.75 m (h): D- shaped |
| Surge Tank | Restricted Orifice Type |
| Type | |
| Size | 51.0 m (h), 5.5 ~5.8 m (dia) |
| Size of Orifice | 1.24 m (dia). |
| Penstock | |
| Size | 1020 m (l), 1.06 ~ 2.5 m (dia) |
| Powerhouse | |
| Type | Surface |
| Size | 55.3 m (l) x 13 m (b), 25.8 m (h) |
| Tailrace | 14 m (l) x 5.5 m (b) x 2.7 m (h) |
| Turbine | |
| Type | Pelton, Vertical Axis |
| Capacity | 3 Nos., 15 MW each |
| Generator | |
| Type | 3 Phase Synchronous AC |
| Rated Power | 3 Nos., 16.85 MVA each |
| Installed Capacity | 42.5 MW |
| Transmission Line | |
| Length | 1.5 km |
| Voltage | 132 kV |
| Annual Energy Generation | 251.94 GWh |
| Dry Months Energy | 35.71GWh |
| Wet Months Energy | 216.23 GWh |
| Salable Energy | 241.86 GWh |
| Dry Month Energy | 34.28 GWh |
| Wet Month Energy | 207.59 GWh |
| Project Cost | |
| Total Project Cost (2011 Dec) | NRs. 5024.29 million |