Survey works for 500 kV line September 1, 2017 | Asia Pacific Tenders Competitive bids are invited for undertaking investigation and preparation of survey for the 178-km-long (approximately), 500 kV Bang Saphan 2–Surat Thani 2 (circuits 3 and 4) line. This content is available to only paying subscribers. Username or E-mail Password Remember Me Forgot Password