BTS NEEPCO Rectification of cracks in penstock short · 2020. 6. 18. · RECTIFICATION OF CRACKS IN...
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RECTIFICATION OF CRACKS IN PENSTOCK voestalpine Bohler Welding supported the project of national (India) importance, the “KAMENG HYDRO ELECTRIC PLANT” of North Eastern Electric Power Corporation Limited (NEEPCO) by supporting the contractor for repair welding of penstocks which not only had posed a serious threat but also developed to be an extreme challenge in repair welding. www.voestalpine.com/welding Source: https://www.neepco.co.in/projects/hydro-projects/kameng-hydro-electric-project Situated in West Kameng District of Arunachal Pradesh, the Kameng H.E. Project (600 MW) is a run-of-the river scheme which will utilize the flows from Bichom and Tenga Rivers (both tributaries of the River Kameng) over a gross head of 536 m. The Project comprises of two Dams and water is transported through a Head Race Tunnel (HRT) & Penstock (HPT) into the Kimi Power House for driving 4 Vertical Fran- ces Turbines,150 MW each. When water was released from the dam, it started leaking from multiple places of the penstock which further on led to cracks in the HPT. Accumulating challenges Approximately half of the number of weld joints were found to be defective and the defects were found in: » Water leakage through grout plugs » Cracks & Pinholes in weld joints » Offsets in weld joints As the penstocks were under concrete roofing and under rocks/mountains, there were very limited chances of any repeated repairs or replacements. Therefore, all the welding repair had to be done in one go. The repair procedure be- came even more difficult due to continuous flow of water inside the penstocks at points where welding had to be performed. With this initial situation, the team of voestalpine Böhler Welding India had to find the perfect welding consumable which could perform in full proof manner similar to under water conditions.
Transcript of BTS NEEPCO Rectification of cracks in penstock short · 2020. 6. 18. · RECTIFICATION OF CRACKS IN...
RECTIFICATION OF CRACKS IN PENSTOCK
voestalpine Bohler Welding supported the project of national (India) importance, the “KAMENG HYDRO ELECTRIC
PLANT” of North Eastern Electric Power Corporation Limited (NEEPCO) by supporting the contractor for repair welding
of penstocks which not only had posed a serious threat but also developed to be an extreme challenge in repair
welding.
www.voestalpine.com/welding
Source: https://www.neepco.co.in/projects/hydro-projects/kameng-hydro-electric-project
Situated in West Kameng District of Arunachal Pradesh, the Kameng H.E. Project (600 MW) is a run-of-the river scheme which will utilize the flows from Bichom and Tenga Rivers (both tributaries of the River Kameng) over a gross head of 536 m. The Project comprises of two Dams and water is transported through a Head Race Tunnel (HRT) & Penstock (HPT) into the Kimi Power House for driving 4 Vertical Fran-ces Turbines,150 MW each.
When water was released from the dam, it started leaking from multiple places of the penstock which further on led to cracks in the HPT.
Accumulating challengesApproximately half of the number of weld joints were found to be defective and the defects were found in:» Water leakage through grout plugs» Cracks & Pinholes in weld joints» Offsets in weld joints
As the penstocks were under concrete roofing and under rocks/mountains, there were very limited chances of any repeated repairs or replacements. Therefore, all the welding repair had to be done in one go. The repair procedure be-came even more difficult due to continuous flow of water inside the penstocks at points where welding had to be performed.With this initial situation, the team of voestalpine Böhler Welding India had to find the perfect welding consumable which could perform in full proof manner similar to under water conditions.
M/S AQUAGREEN ENGINEERING MANAGEMENT PVT LTD (CONTRACTOR) OF KAMENG HYDRO ELECTRIC POWER PLANT (NEEPCO, INDIA) – WELDING UNDERWATER TO RECTIFY CRACKS IN PENSTOCKS OF A HYDRO POWER PLANT
Project summary with customer benefits
FILLER MATERIALS, BASE MATERIALS ANDWELD REQUIREMENTS
Phoenix Nautica 20
DIN 2302E 42 0 Z RR 2 UW 10 fr
BÖHLER FOX EV 85
EN ISO 18275-A: E 69 6 Mn2NiCrMo B 4 2 H5EN ISO 18275-B: E7618-G A H5AWS A5.5: E11018-GH4R / E11018MH4R (mod.)AWS A5.5M: 7618-GH4R / E7618MH4R (mod.)
BÖHLER FOX EV 65
EN ISO 18275-A: E 55 6 1NiMo B 4 2 H5EN ISO 18275-B: E6218-G A H5AWS A5.5: E8018-GH4R / E8018-D1H4RAWS A5.5M: E5518-GH4R / E5518-D1H4R
Base materials
ASTM A517 Grade F, P No: 11B Group No: 3Base metal thickness: 50mm
Weld types
Circumferential and longitudinal butt weldsFillet welds
Mechanical requirements: weld
For BOHLER FOX EV 85YS ≥ 690MPa, UTS ≥ 760-960MPa, %El ≥ 17%CVN @-20°C : 47Joules
BOHLER FOX EV 65YS ≥ 550MPa, UTS ≥ 620-780MPa, %El ≥ 18%CVN @-20°C : 47Joules
Additional weld requirements
Leak proof weld repairs
CUSTOMER BENEFITS
» Reduction of lead time in the repair procedure» Cost savings due to higher efficiency» Repair PQR qualified» Onsite training of welders/operators
voestalpine Böhler Weldingwww.voestalpine.com/welding
JOIN! voestalpine Böhler WeldingWhy we? Because we have over 100 years of experience, more than 40 offices in 25 countries, 2,300 employees and more than 2,000 distribution partners around the world. This guarantees customer proximity, individual solutions and permanent innovation. In order to meet your requirements and wishes, voestalpine Böhler Welding has developed three specialized product brands. Perfectly coordinated. And as unique as your company.
The team of voestalpine Böhler Welding India recreated the customer application and problems in a simulation at their ATC to perform mock-up trials and after successful in-house trials submitted two of their best-in-class stick electrodes „Phoenix Nautica 20“ and „Böhler FOX EV 85/65“ along with a WPS to the customer.
Welding in wet environment can be regarded as a procedure
that is much more difficult to operate. It requires trained welders with high practical skills, excellent knowledge and an extremely high amount of concentration on the job during the whole operation.Therefore, additionally to the materials, voestalpine Böhler Welding India provided special training for the involved welders in the project, to operate the consumables in the perfect and most efficient way.
