IEC 60700-1:2015 applies to thyristor valves with metal oxide surge arresters directly connected between the valve terminals, for use in a line commutated converter for high voltage d.c. power transmission or as part of a back-to-back link. It is restricted to electrical type and production tests. The tests specified in this standard are based on air insulated valves. For other types of valves, the test requirements and acceptance criteria can be agreed. This edition includes the following significant technical changes with respect to the previous edition.
a) Definitions of terms "redundant thyristor levels", "thyristor level", "valve section" have been changed for clarification.
b) The notes were added to test requirements of dielectric d.c. voltage tests for valve support, MVU, valve, specifying that before repeating the test with opposite polarity, the tested object may be short-circuited and earthed for several hours. The same procedure may be followed at the end of the d.c. voltage test.
c) Table 1 on thyristor level faults permitted during type tests was supplemented.
d) The alternative MVU dielectric test method was added.
e) It was specified that production tests may include routine tests as well as sample tests.
f) It was added into test requirements for periodic firing and extinction tests that a scaling factor for tests shall be applied when testing with valve sections.