Some people like to use "a complete set" or "package" for 成套. I don't like it.

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Note added at 38 mins (2009-01-17 19:50:54 GMT)
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http://dictionary.reverso.net/english-definitions/turnkey pl...

Turnkey - denoting a project, as in civil engineering, in which a single contractor has responsibility for the complete job from the start to the time of installation or occupancy

Turnkey project - a complete project usually including many major units of plant completed under one overall contract, such as a chemical works or power station complex


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Note added at 21 hrs (2009-01-18 16:16:25 GMT)
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Or “a large-scale integrated plant”

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Note added at 1 day22 hrs (2009-01-19 18:01:17 GMT)
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所谓“大型成套装置”，通常是指大型的配套生产装置(a large-scale integrated plant)，其中包括许多生产单元(units)。例如一个45万吨乙烯生产装置可包括石油分馏单元、轻柴油裂解单元、高压聚乙烯生产单元、污水处理单元等等。每个生产单元也可以说是 "a complete set of equipment”。所以，若用"a complete set of equipment”就可能会引起误解。“a complete set” 确实可以表示“成套”的意思，例如”a complete set of tools”，但我个人认为用于表示“大型成套装置”则不大合适。

另外，请参考英汉化学化工词汇：packaged plant (=packaged unit) – 小型装置；可移动装置

一个“大型成套装置”可以包括许多 “package plant”。