Suzlon completes blade retrofit program
Suzlon Energy Limited (SEL), the world’s third leading* and India’s largest wind turbine manufacturer, announced the completion of its worldwide program to strengthen and reinforce all Suzlon blades of the V2 type on its S88 – 2.1 MW turbine fleet.
Instances of blade cracks were first discovered in late 2007 during the operation of some of Suzlon’s S88 wind turbines in the United States. Suzlon responded immediately and launched a detailed root cause analysis and identification process, followed by extensive testing of the solution and a comprehensive retrofit operation to safeguard and enhance 1,251 (or 417 sets) of S88-V2 blades around the world – a commitment of approximately USD 100 million, already provided in FY2008-09.
Said Mr. Andy Cukurs, Chief Executive Officer of Suzlon Wind Energy Corporation: “We are happy to report the completion of the program in September, 2009. This project has been a priority effort for us, and our Technology and Project teams have worked hard to complete this project within the shortest possible time. After receiving the first report of cracks in the S88-V2 blades, we immediately undertook a root cause analysis to identify the problem, devise a solution, and resolve the issue in a timely and cost-effective manner. We believe we are the custodians of our customers’ investment and, in keeping with our commitment to our customers, decided to retrofit the entire S88 V2 fleet and replace the few cracked blades at our own cost to eliminate any possibility of further issues, no matter how small the chance.”
In parallel with strengthening the S88-V2 blades, Suzlon also introduced the next-generation S88-V3, which is consistently delivering and exceeding performance standards at windfarms around the world. One of Suzlon’s S88 turbines produces enough energy to power approximately 500 average American homes.**
Speaking after the completion of the retrofit program, David A. Drescher, Vice President – John Deere Renewables, said: “We are pleased that Suzlon has completed the replacement of the blades in our S-88 fleet and is addressing other product support requirements.”
Speaking on successful completion of the S88 type certification with the modified blade design, about the testing protocol applied Christian Nath, Vice President – Germanischer Lloyd, said: “Analysis that implies the effect of 3-D loading and design was used for the verification of the modified blade design. Testing beyond the normal scope of IEC 61400-23 was applied to prove the design’s feasibility.”
The Retrofit Process was carried out in a multi-stage process detailed below:
Root Cause Analysis and Identification
§ Working directly with its customers, Suzlon engaged Navigant Consulting, a leading international consulting firm, to conduct an extensive Root Cause Analysis (RCA) examining all primary and secondary contributing causes to the blade crack issue.
§ The RCA team concluded that the S88-V2 blade design, while designed and tested to industry standard certification guidelines, had a weakness in the transition area – about 6 meters (20 feet) from the root of the blade. The blades measure 43 meters (142 feet) long and weigh 7 tonnes (15,650 pounds).
§ At the completion of the program, only 179 blades of the total fleet of 1,251 blades developed cracks. However, Suzlon upgraded the entire fleet in support of its customers.
Design Solution and Testing
§ To resolve the blade cracking issue, Suzlon added the following to the S88-V2 blade:
– Three additional plies of fiberglass to the blade’s exterior in the transverse direction. These plies extend over the entire blade surface in the transition area.
– One additional ply was added to the interior of the blade.
§ The new reinforced S88-V2 blade has lower stress and strain level in the transition area, preventing cracks from forming.
§ Suzlon worked with Germany-based Germanischer Lloyd (GL), an internationally-recognized wind energy certification organization, to test and certify the V2 blades according to international standards.
§ Through this process Suzlon has developed a new level of blade testing for all its blades by putting increased loads into the test process which exceed current industry standards, raising the bar in product design and testing for the industry as a whole.
