PROMEEC - Industry Activities
in the Lao PDR
Nam Ngum 1 Hydro Power Plant
Present byMr. Vanthong KHAMLOONVILAYVONGPosition : Deputy Manager of Nam Ngum Hydropower Plant
Mailing Address (Company) :Electricite du Laos (EDL).
Nam Ngum Hydropower Plant
Keo Oudom District
Vientiane Province, Lao PDR.
EDL, P.O.Box 309.
Phone (with country code)
Tel: (00856-023) 431 141
Mobile : 020 5523 147
Tel/Fax (with country code)
Fax: (00856-023) 431 223
E-mail : vanthongk@yahoo.com
1Experience and Application ofEnergy Efficiency and Conservation in
Nam Ngum Hydro Power Plant

Installed capacity 155 MW
Number of Units : 52

Background– Dam Site is
Located on theNam Ngum riverabout 75 km
to the northof Vientiane
Capital City.

Central-1 Region

3

Background•Reservoir: 8,460 km2
Normal Max. water level : 212.00 masl
Draw down water level : 196.00 masl
Reservoir surface: 370 km2
(at 212.0 masl)
Storage capacity: 7,030,000,000 m3(at 212.0 masl )Active storage capacity : 4,700,000,000 m3
Drainage area•

DamTypeHeightLengthVolumeSpillway
Design flood•: Mass-Concrete gravity: 75 m: 468 m: 350,000 m3: Radial gate (12.5x10)x4 Nos.
: 3,800 m3/sec

Installed capacity

Installed capacity
Number of units
Unit No.1&2
Unit No. 3, 4&5
Maximum head
Minimum head
Turbine: 155 MW: 5
: @ 17.5 MW: @ 40 MW: 45.5 m: 28.5 m: Vertical Francis Type4

• Energy Generation from 1972 to 2006
Nam Ngum Power station
1200
11391153
1117
1032

1000

10431055

910
847

863

891 907

1046
979

966
898 886

1127

920
867

844

821

800
698

798
683
604

600

567 553481

400
302200215241 252 241 232 25601972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

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Rerf. 02/PROMEEC/01/02
Energy Audit in Lao PDR-PROMEEC
NamNgum I Hydropower plant
Audits: January 28 through February 1, 2002
1.

Two Experts:
1. Mr. Yasunori SERIZAWA
2. Mr. Nobunari KAWAMOTO

2.

Tree Representative each from:
1. Mr. CHAN SOCHEAT

2. Mr. SUBYANTORO S.

3. Mr. U AYE WIN

The Energy Conservation Center, Japan
General Manager Japan international energy& environment cooperation center (ECCJ).
Technical expert
International engineering department (ECCJ).
Cambodia, Indonesia and Myanmar.
Hydropower engineer
Ministry of industry, MINE & Energy
department of energy Technique
Head of Supporting Industries Division
Ministry of energy and mineral resources
directorate general of electricity and energy
utilization directorate of new and renewableenergy and energy conservation.
Executive Engineer (HYDEL)
Myanma Electric Power Enterprise.
6

Recommendation from Audits “ECCJ”• (1) Increasing the power output* Adoption of new runner* Repairs of running water parts* (stay vanes, guide vanes, draft tube and casing)* Painting of penstock (Some parts)
Increase in efficiency of the Generator, Main transformer andmain circuit.
Increase in efficiency of the Turbine.
• (2) Savings in Power Consumption for station Service* Intermittent operation for pressure pumps for governors* Turning off lights for maintenance and check* Use of inverter-control fluorescent lamps• (3) Draw up a highly reliable operation plan for reservoir* The installation of robot rain gauges
7Selecting the Equipment Audited “ECCJ”•••

Unit 5, on other hand, has never had any overhaul. Hence, this unit may presumably
be at the most advanced condition of deterioration over time.
Thus unit 5 was selected for auditing.
No.5 unit in Nam Ngum Hydro Power Plant
1. Turbine :Output: 53000 kW
Type: Vertical Francis
Effective head
: Max. 45.5 m, standard: 37 m, Min. 28.5m
Flow rate: Max. 128.5 m3/s, standard : 117.1 m3/s
Rotation speed: 136.0 rpm
Manufacturer: Hitachi Ltd.
2. Generator :Rated output: 50000 kVA
Rated voltage: 11 kV
Rated power factor: 0.8
Frequency: 50 Hz
Manufacturer: Hitachi Ltd.
3.
Start of operation: 19848(1) Increasing the power output
Status of implementation
Runner cavitations repairs of No.5 unit
(April 24, 2003)
Subject : Repairs Welding Procedure

Runnera. Inlet height
Runnerbladeb. Clearance“D” Section“B” Section

Fig.1. Measuring position for distortion
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Measuring cavitations depth
Tool
a. Cavitations depth
about 10mm.

b. Inspection photorecorded10

Measuring position for distortion
Distortion during repair
a. Inlet height each 90
degrees- Pass, Scale 0.5 mm- before and after work.
b. Outlet clearance “B” &“D” sections of each vane
- Pass, Scale 0.5 mm- Before and after work.
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Cavitations repair• Grinding• Heating withgas flame• Cavitations
damaged area12

(1) Increasing the power output
Relation between Generator Output and Guide Vane Opening test•

Generator Output (kW) at Dec. 4, 1984
Generator Output (kW) at Jan. 31, 2003
Generator Output (kW) corrected into 43.16 m•

The values of generated output, shown above as the test
results, are converted into original test head to allow
comparison with the output at the start of operation.
Assuming that the characteristics of turbines areidentical: 43.16 m and 40.05 m, the figures werecorrected based on the following formula.
Correction formulas that correct 40.05m (at the test date
Jan.31, 2002) into 43.16 m (at commencement time
dated Dec. 4, 1984) are as follows :Pa / Pb = (Hta / Htb)1.5
Where: Pa: Output after correction (kW)Pb
: Output (kW)
Hta : Head (43.16 m)
Htb : Head (40.05 m)
Pa = (Hta / Htb)1.5 x Pb
= (43.16/40.05)1.5 x Pb
= 1.12 x Pb
Pb at 100 % gate opening is 40,800 kW
Therefore ;Pa = 1.12 x 40,800 = 45,696 (kW)This value (45,696 kW) is 97.4 % of the commencement
time value (46,920 kW).
That is 2.6 % decrease than the original values.

13(ECCJ Audited) Recommended Technology/Practice(1) Increasing the power output
Repairs of running water parts* Runners cavitations repair No.5 unit.
Audited estimated of energy savings (No.5 unit)
a.
b.
c.
d.

Power output in 2000 records 322,003,500 kWh/year
Turbine efficiency decrease than the original 2.6%
Turbine efficiency increase after repairs of runner 2%
The increased output after improvement will be as follows:
322,000,000 x (2.6%+2%) = 14,812,000 kWh ~ 15 million kWh/year.

e.
f.

The unit price of electricity export 0.029 US$/kWh
The income is estimated increase per year :14,812,000 x 0.029 = 429,780 (USD) ~ 430,000 USD/year.
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(ECCJ Audited) Recommended Technology /Practice(2) Savings in Power Consumption for station Service* Intermittent operation for pressure pumps for governors.
Audited estimated savings in power Consumption for station service
Operating hours on 2000 records 7,928.32 h.
The annual saving in power consumption for station service :8,760 - 7,982.32 = 831.68 hours/yThe load on the pressure pump during unloading 10 kW/h.
831.68 hours/y x 10 kW/h = 8,316.8 kWh
Furthermore, assuming that the same condition applies to Nos. 3&4, and half of thatamount applies to Nos. 1 &2 units, Total annual saving in electricity consumption in
the plant would be :8,316.8 x 4 = 33,267.2 kWh/year

Governor operating oil has been control daily routine check and ordinary
checks every hours of each unit No.1, 2, 3, 4 & 5 and maintain check oilleakage and air leakage every day.
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Intermittent operation for pressure pumps
for governors.
Pressure Pumps ofThe pressure oil pumps
on-load intervals longer

Unit No. 3, 4 & 5- The seal partsof servomotor- Distributing valves- Oil pressure tankPressure Pumps of Unit N.1 &2No oil leakage

Governors of Unit No.1 & 2

Governors of Unit No.3, 4 & 516

Intermittent operation for Air Compressor
for governors, CB, DS and etc.

The air compressor
pumps on-loadintervals longer- Air valve- Union pipe
No-air leakage

Air Compressor for Circuit
Breaker 115 kV, Disconnecting
Switch 115 kV and etc.

Air Compressor for
Governors of Unit No. 1, 2, 3, 4 & 175

(ECCJ Audited) Recommended Technology/Practice(2) Savings in Power Consumption for station Service* Turning off lights for maintenance and check
Audited estimated annual energy savings turning off lights.
a.
b.
c.

2.

Assuming that outdoor lights is turned off 5 kW/h.
The hours of turned off 4,000 h/year.
Assuming that outdoor lighting of 5 kW is turned off, the annual
energy savings will be as follow:
5 kW/h x 4,000 hours/y = 20,000 kWh/yTurning off lights for maintenance and check.
- Turn off the lights (used “Luxe meter”)- The outdoor lights existing 400 W change to 40 W.
- Turn off the lights for outdoor switch yard equipment area.
- Reduce number of light.
- Turn off the air condition before left office.
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Reduce number and capacity

DoublesSingle400 W40 W

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(ECCJ Audited) Recommended Technology/Practice(2) Savings in Power Consumption for station Service* Use of inverter-control fluorescent lamps

Audited estimated .
a.
b.
c.
d.

Assuming fluorescent lamps 200 Nos.
Capacity 40 W
The hours of the year 8,760 h
The inverter control system electricity savings of 25 %.
40 W/h x 200 x 8,760 h/y x 25 % = 17,520 kWhe.

The adoption of all the plans described above would lead to annual total savingsin electricity consumed in the plant estimated as follows:
33,267.2kWh + 20,000kWh + 17,520kWh = 70,787.2 kWh

3.

Use of inverter-control fluorescent lamps (Not yet)
- Under feasibility study- Reduce number and capacity

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CONCLUSION(1) Increasing the Power Output
Audited estimated of energy savings (No.5 unit)
The power output estimated to increase by approx. 15 million kWh/year
The income is estimated to increase by US$ 430,000 per year(2) Savings in Power Consumption for station Service•
Intermittent operation for pressure pumps for governors : 33,267 kWh/y•Turning off lights for the outdoor reduce the number and capacity : 20,000 kWh/y•
Use of inverter-control fluorescent lamps : 17,520 kWh/y (Not yet) “ Under feasibility
study”
Annual total savings electricity consumed in the plant estimated as follows:
33,267.2kWh + 20,000kWh = 53,267 kWh/yPower consumption for hydropower station service accounts for no more than 1% of
total generated output by the station, and this is very small as compared with that by athermal power plant.
(3) The installation of robot rain gauges(Not yet).
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Thank-You
very muchfor your kindattention

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