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Experience Report

V.P.R. ARIYADASA

REPORTONCEB EXPERIENCEV.P.R. ARIYADASAELECTRICAL ENGINEERLAXAPANA POWER STATIONCEYLON ELECTRICITY BOARD3RD SEPTEMBER 2013TABLE OF CONTENTS21 PERSONAL DATA

2INTRODUCTION23time as the site enginner for mannar district34trainig at power station35 RESPONSIBLE EXPERIENCE5

5.1. SITE ENGINEER AT UTHURU WASANTHAYA5

5.1.1. SCOPE OF WORKS5

5.1.2. ACHIEVEMENTS5

4.1.3.1. SPILLING OF MAUSSAKELLE RESERVOIR

5.1.3. OTHER EXPERIENCES6

5.1.3.1. TESTING OF CONCRETE POLES6

5.1.3.2. WAYLEAVES CLEARING6 5.2. OPERATION ENGINNER AT LAXAPANA POWER STATION7

5.2.1. SCOPE OF WORKS7

5.1.1. DUTIES AND RESPONSIBILITIES8

5.3. MAJOR PROBLEMS AND CRITICAL DECISIONS ENCOUNTERED 8

5.3.1. EMERGENCY LINE SHIFT IN DEYATA KIRULA -20128

5.3.2.EMERGENCY POWER SUPPLY FOR THE PERIYAMADU CAMP9

5.3.3. CLEANING OF POLPITIYA INTAKE9

5.3.4. WATER MANAGEMENT OF LAXAPANA COMPLEX10

5.3.5 NEW LAXAPANA FAILED TO START ON 26TH APRIL 201310

5.3.6.OLD LAXAPANA STAGE II MACHINES TRIP11

..1. Personal dataName

:V.P.R. AriyadasaE.P.F No:37982Date of birth:20th October 1983Nationality:Sir LankanEducation: Bsc(Hons) in Electrical Engineering in 2008

University of Moratuwa, Sri Lanka

Membership ofProfessional societies:Member of the Institution of Engineers Sri Lanka Work Experience:

July 2009 to date

Ceylon electricity board,

Electrical engineer

December 2008 July 2009

Bank of Ceylon,

Electrical Engineer

May 2008 December 2008 Temporary Instructor,

University of Moratuwa2.IntroductionI am pleased to submit this CEB experience report for the consideration of K3 interview to be held in 4th September 2013 at the generation headquarters.I was employed in Ceylon electricity board since 15th July 2009 and currently working as the Operation Engineer at Laxapana Power Station. Before coming to the Generation Division I worked as the Site Engineer for Mannar District in Uthuru Wasanthaya Electrification project under Distribution Division Region 01. 3.Time as the Site Engineer for Mannar District

I was posted to the Uthuru wasanthaya Northern Electrification Project as i joined with CEB. I worked there for three and four months period conducting and supervising power line construction works in Mannar District.

The Uthuru Wasanthaya Electrification Project is to achieve 100% electrification in Northern Province by the end of 2013. The total cost is six billion rupees. Four site engineers were appointed to five districts in order to carry out the power line construction works effectively.

The electrification level was only 35% when the time of August 2009. A main 33KV backbone line ( from Vavuniya ) was available to electrify Mannar town and few other towns on the way. The land was contaminated by land mines and land clearing and resettlements were carried out. Our main task was to coordinate with other government officials and to provide electricity facility for the villages in which the resettlements were carried out.

Other than the normal construction works, duties like conducting scheme openings, material test ( specially concrete pole testing ) were carried out during that period.

4.Training at Power StationsI had to undergo three month of training period to get familiarized about the power stations and duties in Laxapana complex.Laxapana complex consist of five power stations named canyon, Wimalasurendra, Samanala, New Laxapana and Old Laxapana power stations. The oldest power station in CEB which was commissioned in 1950 was the Old Laxapana Power station. Consist of 3 number of 8.33MW generators (Now those were rehabilitated and improved to 9.5MW) in Stage I and 2 number of 12.5MW generators in stage II (1958). New Laxapana Power Station was commissioned in 1974 with 107MW total capacity. Last year (2012) the New Laxapana Unit no. 01 was rehabilitated to 57MW generator. Altogether 160.5MW of power can be supplied to the national grid at once. Pelton turbines are used in all of Old and New Laxapana.

Wimalasurendra Power Station commissioned in 1965 and having two number of 25MW generators. Samanala Power Station which also called as Polpitiya power station was commissioned in 1969 and having two numbers of 37.5MW generators. Canyon Power Station commissioned in 1983 and 1989 having two vertical fransis turbines with total of 60MW. The total capacity of the Laxapana complex is 345 MW now. Laxapana complex has two reservoirs called Catlereigh and Maussakelle and three ponds called Norton, Canyon and Laxapana. The power stations are in a cascaded system and generation of one power station depends on the annual rainfall, machine outages and running period of the other power stations. Therefore the operations of all the power stations are interrelated and are carried out according to the system demand by communicating with system control centre. After the general training in the Hydro Power Station I trained in the Laxapana Power Station as the Operation Engineer for about two months. The important areas that I covered in this training period are: General arrangement of Laxapana power station turbines, generators, connecting transformers, switchyard, distribution feeders etc. Machine & transformer capacities of old Laxapana and new Laxapana power stations Water discharge rates, reservoir/pond capacities and spill & operation levels Spill gates and needle valve operation Operation processes automatic or manual starting and shutdown procedures and machine loading Auxiliary services cooling water system, service water system, auxiliary power supply, bearing oil circulation & cooling system, substation lighting. Switchyard equipment identification and operation procedures Protection schemes for machines, transformers and lines alarm and tripping settings Organization structure of Laxapana complex, line of authority Responsibilities of technical assistants, technical officers, control room operators etc. Documentations log sheets, water level and rainfall book, daily machine and line outage, monthly statically data, weekly spill data, duty assignment to junior staff. 5.Responsible experience5.1 Site Engineer at Uthuru Wasanthaya Northern Electrification Project (from July 2009 to December 2012)5.1.1. Scope of work

To perform the power line construction works soon, ensuring the construction standards, the safetiness of the workers as well as the public and to utilize the fund allocation more effectively. 5.1.2. Achievements Before starting the project, the electrification level in Mannar district was 35%. Within that period we could increase that level to 76%. In some villages, the villagers experienced the benefits of electricity for their first time. To achieve that level we had to utilize about 726 Million rupees. All the constructions were carried out by private contractors under the supervision of CEB staff. The following table shows the summery of the schemes which were completed during the time as site engineer (Mannar) for Uthruru Wasanthaya project.

5.1.3 Other Experiences Other than normal construction works, we could achieve plenty of experiences on other relates subjects as well.

5.1.3.1Testing of Concrete Poles

The main cost component of the project was the cost for concrete poles. All the poles were purchased locally and prior to that a CEB official should test the materials whether those are according to the standards and approve. The testings were mainly done for 8.5m/100kg, 11m/300kg, and 11m/500kg poles.

Other than that, some testings on Galvanised cross arms, Stay assemblies, etc. were done on request.

5.1.3.2Way leaves clearing

Before energising a scheme, way leaves must be cleared according to the standards. Due to the community participation is a must we get together with the villagers and arrange a campaign to cut way leaves with a guidance of the CEB official.

When the community participation was not available, quotations were called and arrange contractors to cut the way leaves ensuring the standards.

5.2 Operation Engineer at Laxapana power station (from May 2013 to August)5.2.1. Scope of workTo ensure safe and smooth operation of power station while maintaining efficiency of the plants and equipment in the power station up to the switch yard line isolator and to ensure personally that the power station contributes its share of the system load as required and planned up to the maximum at all times.5.2.2. Duties and responsibilities: Personally responsible for all operations in the power station and the switchyard when on shift duty. To startup, synchronize and load generating units as and when required. To shut down generating units as and when required. To report immediately to the chief engineer or engineer in charge of the power station any serious defect or breakdown of plant or equipment and to furnish a complete report of the breakdown. To inform system control of any plant non availability/breakdown in proper time. To conduct switching operations of feeders in case of breakdown/interruptions. To restore supply in the shortest possible time in the event of partial or total failure due to plant of feeder failures. To isolate and make safe any plant, equipment, switchgear or feeder back into commission after the maintenance or repair work is over. To operate an agreed scheme whereby all operating personnel not up to the required standard could be trained effectively and efficiently to acquire the required competence in the shortest possible time. To ensure that the CEB and the factory safety rules and regulations are strictly adhered to. To maintain records of attendance of operating staff and all statical data (loading of sets, feeders, water levels etc). To approve leave of the operating staff and cover-up arrangements.5.3. Major problems and critical decisions encountered

5.3.1. Emergency line shift in Dayata Kirula 2012

On 20th January 2012, an emergency decision was taken to shift a distribution power line from Pandulagama towards Mirisawatiya area. It was only a 10 day period was given to complete the task though no fund and material allocation done early. The line was consist of 5.2km HT line and a UHT line which need a considerable amount of materials and considerable amount of time to complete.

So what I did initially was the selection of the right contractor for that job. In order to select the contractor, they should have proper capacity to handle that kind of emergency tasks. After selecting the contractor, I immediately instruct them to start it with whatever they can. Instruct him to use materials which were allocated to some other jobs and provided some essential materials using waybills. Also wayleave clearing also initiated in parallel. The work was carried out such a way that the line can be reenergized in every night peaks.

After the hard works, the line was completed within 10 days of period. Since we took the right decision on the right time we were able to accomplish our goal.

5.3.2 Emergency power supply to the Periyamadu Camp

This was happened on in October, 2011. Four day emergency function was arranged in the Periyamadu camp (in Mannar) requesting immediate power supply from CEB. That time no LT power line was available only the transformer was installed 2.5km away from the function location. We had only two days of time period to provide supply.

So we didnt have enough time to construct LT power line for that purpose. So we discuss with the army and started to draw the LT power line on bare land. Since we used Arial Bundle Cables (ABC) we had enough insulation without getting earthed. Also arrange some army people for the protection of the power line, safeguarding power line from the people.

The function was very successful and we were able to provide power supply throughout the event.

5.3.3 Cleaning of Polpitiya intakeWhen Polpitiya intake screen of Laxapana pond was blocking, the water level in the intake was decreasing very rapidly even though the pond level was close to spill level. This was due to the trash collected at the intake screen. This situation becomes worse if the level went down close to 20fts, which was the MOL of the Laxapana pond. Therefore I informed this to CE and arranged to clean the intake as soon as possible. As a result it was decided to clean the intake by obtaining the service from master divers (pvt) ltd. For this purpose all the generators at old Laxapana, new Laxapana and Polpitiya have to be kept in minimum load (some time shutdown some machines). This should be planned from the previous day and all three ponds should be at minimum level when the machines are stopped. Arrangement of auxiliary supply during this period for both N/L & O/L power stations is also a major consideration for operations engineer. After completing the cleaning work it was required first to start the Laxapana machines and fill the Laxapana pond. This is done slowly in order to avoid air trapping in the tunnel. When the pond filled over the minimum operating level the pond could be filled faster and also Polpitiya machines can be started.

5.3.4 Water management of Laxapana ComplexAs Laxapana, Norton and canyon ponds are regulating ponds, balancing the water level of the ponds during the day time to meet the night peak of the system is a major requirement. The regulation of the pond levels are carried out by the operation staff under the instruction of system control centre. The operations engineer is considered to be at full awareness about the pond levels and load of the generators of the complex. Necessary day to day information about the weather pattern, side flows to the pond etc are given to the system control centre, and in some occasions necessary changes to the day to day operating pattern is done with the co-ordination of the system control centre.In some occasions there is unexpected rain. As a result, within 2-3 hours, all regulatory ponds may get spilled. In this kind of situation we have to take immediate action for the safety of dams, proper operation of Polpitiya machines and the people in the downstream. There are some polices stations and disaster management centre which operation engineer is responsible to inform prior to gate openings. When canyon gates opened, the water level will rise at Laxapana pond within 45 minutes time. If Laxapana pond is at the top level at that time sudden rise of water may damage the dam. So we should prepare that situation by opening the gates at Laxapana.5.3.5 New Laxapana No.1 Machine failed to start on 26th April 2013The N/L Unit No.01 was taken for the R/M and tried to restart the machine at 16.45p.m. A quick shutdown appeared indicating TSLG minor fault of high level in pressure tank. The oil level must be brought down within the range of 568mm 441mm in order to satisfy the condition.What I did was, drain some oil from the bottom of accumulator pressure tank. That draining oil goes to governor oil sump tank though the existing oil path. When the oil draining occurs, the accumulator oil pressure reduces accordingly. The air pressure should be within 26-28 bars in order to satisfy the condition. Since it was dropping (about 25 bars) I had to manually open the air ( from the air compressor tank ) in order to bring the air pressure to satisfactory level. We observed that ( using historical data on ALSTOM SCADA system) the accumulator oil level always goes high in some extend. That was because of the compressor air releasing valve opening time was not enough in that time. ( normal setting was 60s for 600s) We asked the ALSTOM officer to increase the opening time for some more time. ( now the setting is 100s for 600s period) The problem solved.

5.3.6 Old Laxapana Stage II machines trip The O/L Stage II machines no. 04 and no. 05 suddenly tripped at 5.00 a.m. indicating inverter supply fault. It was very important to restart the machines due to the spilling of Norton pond because of the heavy rainy situation. The machine AC pumps were fed by three main supply paths. Default is the feeding AC supply from the DC battery supply inverted using AC inverters and feed the pumps. Second is getting AC supply from auxiliary transformer supply and perform AC-AC conversion and feed. The third and last option is the bypass mode which directly supplies the AC from auxiliary transformer supply.

In this situation, the initial two options were not supported since the fault remains and preventing restarting of generators. Only bypass mode was supporting and hence restarted the machines using that mode and load immediately to reduce the water wastage. Due to the change of auxiliary transformer lead to trip the machine again instruct operation staff to be on alert.

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