IEC 61954-2021 pdf free download – Static VAR compensators (SVC) – Testing of thyristor valves.
The tests described apply to the valve (or valve sections), the valve structure and those partsof the coolant distribution system and firing and monitoring circuits which are contained withinthe valve structure or connected between the valve structure and earth.Other equipment,such as valve control and protection and valve base electronics may be essential fordemonstrating the correct function of the valve during the tests but are not in themselves thesubject of the tests.
4.2.2Dielectric tests4.2.2.1General
Tests for the following dielectric stresses are specified:-AC voltage;
– combined AC and DC voltage (TsC only);- impulse voltages.
In the interest of standardization with other equipment, lightning impulse tests between valveterminals and earth and between phases of an MvU are included.For tests between valveterminals, the only impulse test specified is a switching impulse.
4.2.2.2Tests on valve structure
Tests are defined for the voltage withstand requirements between a valve (with its terminalsshort-circuited) and earth, and also between valves for MVU. The tests shall demonstratethat:
– sufficient clearances have been provided to prevent flashovers;
– there is no disruptive discharge in the insulation of the valve structure, cooling ducts, light
guides and other insulation parts of the pulse transmission and distribution systems;
partial discharge inception and extinction voltages under AC and DC conditions are abovethe maximum steady-state operating voltage appearing on the valve structure.
4.2.2.3Tests between valve terminals
The purpose of these tests is to verify the design of the valve with respect to its capability towithstand overvoltages between its terminals. The tests shall demonstrate that:
sufficient internal insulation has been provided to enable the valve to withstand specifiedvoltages;
partial discharge inception and extinction voltages under AC and DC conditions are abovethe maximum steady-state operating voltage appearing between valve terminals;
the protective overvoltage firing system (if provided) works as intended;
the thyristors have adequate du/dt capability for in-service conditions. (In most cases thespecified tests are sufficient; however, in some exceptional cases additional tests may berequired.)
4.2.3operational tests
The purpose of these tests is to verify the valve design for combined voltage and currentstresses under normal and abnormal repetitive conditions as well as under transient faultconditions.They shall demonstrate that,under specified conditions:
– the valve functions properly;
– the turn-on and turn-off voltage and current stresses are within the capabilities of the
thyristors and other internal circuits;
– the cooling provided is adequate and no component is overheated;- the overcurrent withstand capability of the valve is adequate.
4.2.4Electromagnetic interference tests
The principal objective of these tests is to demonstrate the immunity of the valve toelectromagnetic interference from within the valve and from outside the valve.Generally,immunity to electromagnetic interference is demonstrated by monitoring of the valve duringother tests.
4.2.5Production tests
The objective of tests is to verify proper manufacture. The production tests shall demonstratethat:
– all materials，components and sub-assemblies used in the valve have been correctly
installed;
the valve equipment functions as intended, and predefined parameters are withinprescribed acceptance limits;
thyristor levels and valve or valve sections have the necessary voltage withstandcapability;
-consistency and uniformity in production is achieved.
4.2.6Optional tests
Optional tests are additional tests which may be performed, subject to agreement between thepurchaser and the supplier. The objectives are the same as for the operational tests specifiedin 4.2.3. The test object is normally one valve or appropriate equivalent number of valvesections.
4.3Guidelines for the performance of type and optional testsThe following principles shall apply:
– type tests shall be performed on at least one valve or on an appropriate number of valve
sections，as indicated in Table 1 (see 4.1), to verify that the valve design meets thespecified requirements. All type tests shall be performed on the same valve(s) or valvesection(s);
provided that the valve is demonstrably similar to one previously tested, the supplier maysubmit a certified report of any previous type test，at least equal to the requirementsspecified in the contract, in lieu of the type test;IEC 61954 pdf download.