Latvian TSO to invest EUR518 million in grid development during 2017-24 August 23, 2016 | Europe News Latvian transmission system operator (TSO) Augstsprieguma tīkls AS (AST) is planning to invest around EUR518 million in its high voltage transmission lines during the period 2017-2024. This content is available to only paying subscribers. Username or E-mail Password Remember Me Forgot Password