I. Overview
Gb 3906-19913 ~ 35kv AC metal enclosed switchgear has been implemented for more than ten years. During this period, great changes have taken place in the design, manufacture, test and operation of high-voltage AC metal enclosed switchgear, and the level has been greatly improved. Therefore, in 2000, the National Technical Committee for Standardization of High Voltage Switchgear decided at its annual meeting to comprehensively revise GB 3906- 199 1, and followed the comprehensive revision of IEC 60298: 1990. This standard was drafted by Xi 'an Institute of High Voltage Electrical Apparatus.
During the revision of GB 3906- 199 1 by the standard revision working group, IEC is also carrying out a comprehensive revision of IEC 60298: 1990. Therefore, the Standards Committee decided that the drafting unit responsible for standards should keep track of the revision trend of IEC 60298: 1990 at any time. In June 2003, IEC published IEC 6227 1-200: 2003 "High-voltage switchgear and controlgear-Part 200: AC metal enclosed switchgear and controlgear with rated voltage 1 kV and below" (corresponding to the original IEC 60298). Therefore, the standard revision working group revised the draft standard again according to IEC 6227 1-200: 2003, formed a draft for comments, and sent it to relevant units for comments. In September 2004, it passed the examination of the second plenary session of the fourth session of the Standardization Committee, and the secretariat reported it in February 2005 after completing the standard examination. According to the relevant regulations of WTO, mandatory standards need to be notified to WTO members, so the formal approval time of standards was postponed to August 25, 2006.
2. The main differences between this standard and GB 3906-19913 ~ 35kV AC metal enclosed switchgear.
-The word "metal enclosed switchgear" was changed to "metal enclosed switchgear and control equipment";
-A new classification method for metal enclosed switchgear and controlgear was added, and the old classification method was deleted;
-The concepts of "cabin category" and "zone level" and related contents have been added;
-The concept of "loss of continuity of business categories" has been added, and relevant contents have been added;
-The concept of "Internal Arc Level Switchgear and Control Equipment (IAC)" and related test contents have been added;
—— Defining the selection method of short-term withstand current value of grounding circuit;
-Relevant requirements and tests of "electromagnetic compatibility" have been added;
—— "Test for evaluating internal fault arc effect" and "Electromagnetic Compatibility Test (EMC)" are taken as "mandatory type test items when applicable", and "Insulation test of cable test loop" is added to the selected type test items;
-Anticorrosion requirements and related verification tests have been added;
—— The qualification standard of "lightning impulse voltage test" was clarified, and "voltage test as state check" was added;
Added "provisions on cable insulation test";
-The requirement of "the protection level of the shell is not lower than IP2X" has been added;
-Added "Additional Testing of Auxiliary and Control Circuits";
-The specific content of "closed breaking test" has been added;
-The specific requirements of "Mechanical Operation and Mechanical Characteristic Measurement Test" have been revised;
-Added "Pressure Withstand Test of Inflatable Chamber and Gas State Measurement";
—— The content of "running vibration test" was deleted from the type test project;
—— Deleted "5 min pressure test at zero gauge pressure of inflatable cabin";
-Added "Guide to Selection of Switchgear".
Three. Description of related issues
1. Product classification
Classification is no longer based on the structure of products, but on the continuity of operations provided by products. This product is divided into LSC2B, LSC2A and LSC 1. Among them, LSC2 B provides the highest operational continuity, LSC2 A provides the second, and LSC 1 provides the lowest.
LSC: LSC represents the loss level of operation continuity when the main circuit compartment is opened, that is, the degree to which the bus/cable compartment remains charged.
LSC 1: 1+0 means that all rooms can't run continuously except the switch cabinet room of the functional unit.
Lsc2: 2 means that all functional units can run continuously except the switchgear compartment of functional unit *.
Lsc2a: A way to open the switch equipment compartment of a functional unit, and at least one remaining compartment of the functional unit can run continuously.
A) There is a partition between every two functional units;
B) At least two compartments, and each functional unit has at least one breakpoint.
Lsc2b: b means to open the switch cabinet room of the functional unit, and other rooms of the functional unit can continue to operate.
A) There is a partition between every two functional units;
B) There are at least three intervals, and each functional unit has at least two breakpoints.
LSC 1-PM: PM: PM means that the diaphragm and valve are metal.
Lsc2b-pi: pi means that at least one diaphragm or valve is non-metallic.
* If the bus compartment in the single-bus system is open, the compartments of all functional units on the bus can be opened.
2. About the classification of compartments
According to the accessibility of the equipment cabin, the equipment cabin can be divided into three types: accessible cabin controlled by interlocking, accessible cabin based on program, accessible cabin based on tools and inaccessible cabin.
Interlocking controlled accessible compartments and program-based accessible compartments are compartments that need to be opened for daily operation and maintenance. No tools are needed to open these two compartments, and the interlocking controlled accessible compartment can be opened through interlocking control in product design. Accessible compartments based on programs need special programs and locks to open, where programs can be interlocking or operating programs of equipment; Tool-based accessible compartments do not need to be opened during normal operation and maintenance. If you need to open it, you need special programs and tools. The procedure here is the same as the above procedure, and it can also be the interlocking or operation procedure of the equipment. Tools can be all tools including locks. Unapproachable compartments are compartments that users cannot open. If it is opened, the integrity of the compartment cannot be guaranteed.
3. About the classification of clapboards
According to whether the diaphragm and/or valve are all metal or nonmetal, the diaphragm of the product is divided into PM grade and PI grade.
Actually, the correct classification of continuity loss of switchgear and controlgear is LSC 1, LSC 1-PM, LSC 1-PI, LSC2A-PI, LSC2B-PM and LSC2B-PI. See the table above for details and examples.
4. Classification of products according to internal fault arc.
According to the safety level provided by the product in terms of internal fault arc, the internal arc level switching equipment and control equipment (IAC) are defined. For internal arc-level switchgear and control equipment (IAC), internal fault arc test is required. The test current is rated short-term withstand current, and the suggested test duration is 1s, 0.5 s and 0.1s. The equipment that passed the test is internal arc-level switchgear and control equipment (IAC), and the characteristic parameters of internal fault arc test are specified on the nameplate.
5. Verification of closing and disconnecting ability
Because the products for type test cannot cover all possible layouts and designs of switchgear, this standard gives three test procedures to accurately determine the test combination according to the specific characteristics and location of switchgear:
(1) When all switching elements and compartments are redesigned, they shall conform to 6.101.a) of this standard;
(2) When the car structure is redesigned and the same switch device is adopted, it shall meet the requirements of 6. 10 1.b) of this standard;
(3) When the carriage structure is not modified and various types of switch devices are adopted, the type test shall be conducted according to the above (1) or (2).
6. Mechanical running test (mechanical life GB 3906- 199 1)
In the 7.6.3 mechanical life test of GB 3906- 199 1, it is stipulated that "... circuit breakers, load switches, contactors, disconnectors and their operating mechanisms, and ... shall be evaluated according to the times of product technical conditions." This standard is revised as follows:
(1) If the extractable or detachable parts are used as disconnectors, the test shall comply with GB 1985-2004;
(2) when the switch cabinet (such as circuit breaker, load switch, isolating switch, grounding switch, etc. ) and its operating mechanism are designed as a whole, and their mutual positions (mechanism and body) have not changed when the switchgear is tested separately, so it is not necessary to carry out mechanical operation test.
(3) For split switchgear (such as circuit breakers, load switches, disconnectors, grounding switches, etc.). ), the number of operations and the qualified standard of mechanical operation test shall be carried out according to the technical conditions and relevant standards of switchgear.
This standard is coordinated with current laws, regulations and policies and related basic standards, and should be used in conjunction with GB/T11022-1999.