IEEE 857-1996 pdf download IEEE Recommended Practice for Test Procedures for High-Voltage Direct- Current Thyristor Valves
1.Scope
This recommended practice contains information and recommendations for the type testing of thyristor valves forhigh-voltage direct-current (HVDC) power transmission systems. Other equipment tests, such as development tests.production sample tests. routine tests. tests for the determination of losses. commissioning tests, and site tests are notwithin the scope of this recommended practice. Furthermore, the tests given here cover the principal tests on the valvesonly and do not include tests of auxiliary equipment associated with the valves. such as cooling system components
This recommended practice applies to any type of line-commutated indoor thyristor valve, with metal-oxide surgearresters connected between the valve terminals, used in converters for HVDC power transmission systems. Anymodifications to these tests and/or additional tests required for outdoor valves are to be considered separately.
2. References
This recommended practice shall be used in conjunction with the following publications:
IEEE Std 4-1995,EEE Standard Techniques for High-Voltage Testing (ANSI).
IEEE Std 100-1996,IEEE Standard Dictionary of Electrical and Electronics Terms.
IEC 60060-1 (1989-11), High-voltage test techniques–Part 1: General definitions and test requirements.~
IEC60060-2 (1994-11), High-voltage test techniques–Part 2: Measuring systems.
IEC 60071-1 (1993-11),Insulation co-ordination–Part 1: Definitions, principles and rules.
IEC 60633 (1978-01), Terminology for high-voltage direct current transmission.
IEC 60700 (1981-01), Testing of semiconductor valves for high-voltage d.c. power transmission.
IEC 60747-1 (1983-01), Semiconductor devices—Discrete devices—Part 1: General.
IEC 60747-5 (1992-05), Semiconductor devices—Discrete devices—Part 5: Optoelectronic devices.
IEC 60747-6 (1983-01), Semiconductor devices—Discrete devices—Part 6: Thyristors.
3. Definitions
Definitions given in this recommended practice apply specifically to the testing of HVDC thyristor valves.
3.1 failure of thyristor level: A thyristor level is deemed to have failed if it becomes short-circuited or in any other way has degraded to the extent to make it functionally inoperative.
3.2 multiple-valve unit (MVU): A single structure comprising more than one valve.
3.3 redundancy factor: The ratio of the total number of series thyristor levels in the valve, N t , to the same number minus the total number of redundant series thyristor levels in the valve, N r . The redundancy factor, f r , is defined by
3.4 redundant thyristor levels: The maximum number of levels in the series string of thyristors in a valve that maybe short-circuited externally or internally during service without affecting the safe operation of the valve asdemonstrated by type tests, and which, if and when exceeded, would require shutdown of the valve to replace the failedthyristors or acceptance of increased risk of failure of the valve.
3.5 single-valve unit: A single structure comprising only one valve.3.6 test withstand voltage: The maximum value of a test voltage at which a new valve, with unimpaired integrity,does not show any disruptive discharge, nor suffer component failures above permissible levels, when subjected to aspecified number of applications of the test voltage, under specified conditions.
3,7 thyristor level: A single thyristor, or thyristors if the valve has parallel connected thyristors, and associatedcomponents for control, voltage grading, protection, and monitoring that constitute a single voltage level within thevalve.
3.8 valve: A converter arm in a three-phase, 6-pulse bridge converter connection.
3.9 valve base: The assembly that mechanically supports and electrically insulates the valves from ground.
NOTE — A part of a valve that is clearly identifiable in a discrete form to be a valve base may not exist in all designs of valves. Avalve base could be a separate platform insulated from ground by post-type insulators that carries a live-tank valve unitor a steel framework insulated from ground by post-type insulators on which the various modules of an MVU aremounted, or a raised platform of insulating material that is integral to the valve structure and forms the base.
3.10 valve module: The smallest assembly, comprising a number of thyristors and their immediate auxiliaries forfiring and protection, voltage-dividing components, and distributed or lumped valve reactors, from which the valve isbuilt up and which exhibits the sae electrical properties as the complete valve but can withstand only a portion of thefull voltage-blocking capability of the valve.
3.11 valve section: An electrical assembly comprising a number of thyristor levels and other components that exhibitsprorated electrical properties of a complete valve.
IEEE 857-1996 pdf download
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