GB/T 20645-2021Specific environmental condition—Technical requirements of low-voltage apparatuses for plateau (English PDF)

3.1 Plateau

Areas above 2000m to 5000m above sea level.

3.2 Solar radiation intensity

The solar radiation power received per unit area.

Note: The unit of solar radiation power is watts per square meter (W/m2).

3.3 Normal product

Products designed and manufactured based on the standard environment specified by the relevant product standards (specifications).

3.4 Plateauproduct

On the basis of conventional products, adjust the original design and configuration to set plateau environmental conditions to achieve plateau products Products required by the standard for normal use.

3.5 Manualsimulatedenvironmentcondition

In order to assess the environmental adaptability of the product, the environmental conditions are artificially set according to the characteristics of the environmental conditions at a certain altitude.

5.1 Contents of the data

The relevant technical documents of the product should not only meet the requirements of the corresponding product standards, but also supplement the use, maintenance, and precautions in the plateau environment.

Item and other special information content, so that users can correctly use low-voltage electrical products in plateau areas.

Outdoor high prototype electrical products should be indicated in the product information.

5.2 Logo

In line with the provisions of the corresponding product standards, the following content should be added to the development and design of high-level prototype products.

The nameplate of the prototype product or the obvious part of the product should have an obvious applicable altitude class mark, in line with GB/T 19607- The requirements of 2004.

The mark of product altitude classification consists of two parts. G× or G×-×. G-indicating product altitude classification; ×-indicated by Arabic numerals Altitude class.

Example: G5 means it is suitable for altitudes up to 5000m; G3-4 means it can be used for altitudes above 3000m to 4000m.

6.1 Normal use conditions

6.1.1 Altitude

The applicable installation altitude is above 2000m to 5000m, and it is divided into a grade for every 1000m.

6.1.2 Ambient air pressure, temperature, humidity, solar radiation intensity

According to the altitude level, the ambient air pressure, temperature, humidity and solar radiation intensity should comply with GB/T 14597-2010 No. 4 The corresponding provisions of the chapter.

If the temperature range used by the product exceeds the ambient air temperature range specified in the normal use conditions of the corresponding product standard, the manufacturer shall According to GB/T 14597-2010, the manufacturer stipulates the allowable limit ambient air temperature range.

6.1.3 Pollution degree

For products that meet GB/T 14048 (all parts) and GB/T 13539 (all parts) except GB/T 13539.3, pollution The level is not less than the pollution level 3 specified in 6.1.3.2 of GB/T 14048.1-2012; for meeting GB/T 10963 (all parts), Products of GB/T 13539.3, GB/T 16916 (all parts) and GB/T 16917 (all parts), the pollution degree is not less than The pollution degree 2 specified in 6.1.3.2 of GB/T 14048.1-2012.

6.1.4 Lightning, condensation and pollution

Chapter 6 of GB/T 20626.3-2006 (except for the medium and high voltage parts in 6.2.2.1, 6.3.1.1, and 6.3.2) is applicable, and is modified as follows.

According to GB/T 19607-2004, my country's climate characteristics and use places, low-voltage electricity used in the following areas specified by the manufacturer The protection requirements that the device should meet.

---The climate of the Yunnan-Guizhou Plateau is characterized by hot and humid, more condensation, and less sand and dust;

---The climate of the Qinghai-Tibet Plateau is characterized by cold temperature, more sand and dust, and less condensation;

---There is a lot of salt fog in the climate near the salt lake.

6.2 Packaging, transportation and storage

6.2.1 Packaging

Should meet the requirements of the corresponding product standards.

In addition to marking in accordance with the packaging of general electrical and electronic products, when necessary, the special transportation and storage requirements should be stated in a prominent position on the packaging. Claim.

6.2.2 Transportation

It should be fixed firmly during transportation to avoid impact and vibration. When necessary, measures should be taken to prevent intrusion of sand, dust, rain and snow, and coldness. There are moving parts The product should be fixed and should prevent sand and dust from entering. Oil-filled and gas-filled products should handle oil pressure, air pressure and product sealing well.

6.2.3 Storage

Prevent the intrusion of sand, dust, rain and snow. Appropriate cold protection measures should be taken. To carry out regular inspections and inspections.

Example 2.When the product use location is 4000m above sea level, the test site is 1000m above sea level. At an altitude of 2000m and below, the standard for conventional products The specified impulse withstand test voltage is 4kV (when the rated impulse withstand voltage is 4kV), the impulse withstand voltage test value tested at an altitude of 1000m should be It is. 4kV×1.44=5.76kV.

7.2.4 The ability to make and break normal loads

7.2.4.1 Operational performance

Under normal load, the making and breaking capacity of various products of low-voltage electrical appliances are slightly affected. The specific number of operations and the number of making and breaking are determined by The manufacturer stipulates in the instructions.

7.2.4.2 Life

Under normal load, the mechanical life and electrical life of various products of low-voltage electrical appliances are slightly affected, and the specific number of operations and the number of switching on and off It is specified by the manufacturer in the instructions.

7.2.5 Critical DC load current

Under plateau conditions, as the altitude increases, the arc extinguishing ability of DC electrical products using free air as the arc extinguishing medium is weakened, thus The critical DC load current value of the product is reduced. The specific value is determined by the manufacturer according to the electrical and mechanical characteristics of the product.

7.2.6 Making and breaking short-circuit current capability

Under plateau conditions, with the increase in altitude, the arc extinguishing capacity of low-voltage electrical products using free air as the arc extinguishing medium is weakened, and from In terms of the degree of influence, DC products are greater than AC products, resulting in a decrease in the ability of products to make and break short-circuit current. Declining value The manufacturer decides according to the electrical and mechanical characteristics of the product.

7.2.7 Tripping characteristics

7.2.7.1 Tripping characteristics of thermal trip elements

Products such as circuit breakers and thermal relays that use thermal trip elements as trip components are affected by plateau conditions due to heat dissipation conditions.

Change, its tripping characteristics will have a certain deviation. However, due to the different electrical and mechanical characteristics of each product, the degree of deviation is somewhat scattered Sex. Therefore, the tripping characteristics of specific products should be adjusted and corrected under the corresponding altitude or simulated environment or equivalent conditions to meet the production requirements.

The requirements of the tripping characteristics of the altitude environment where the product is used.

7.2.7.2 Tripping characteristics of electronic components

In the plateau environment, the tripping characteristics of low-voltage electrical products using electronic trippers are basically not affected by plateau conditions. Therefore, often When the regulated low-voltage electrical products are used in plateau environmental conditions, their tripping characteristics do not need to be adjusted and corrected separately, but electronic products should be fully considered. Heat dissipation of power components.

7.2.8 Low temperature resistance

The low temperature environment in high altitude areas will have the following effects on electrical components.

---The insulating material of electronic equipment is hardened and embrittled, and is easily damaged after being exposed to external stress;

---The toughness of the component material decreases and the brittleness increases;

---The lubricating effect or fluidity of the lubricating oil on the contact surface of the part and the part in the mechanism is reduced, which increases the friction coefficient of the contact surface Cause the mechanism to slow down or even refuse to move.

Low-voltage electrical appliances should have the ability to withstand low temperatures in high-altitude areas. See Table 3 for the minimum temperature values at different altitudes. According to the requirements of 8.7 experimenting.

8.1 General provisions

High prototype products should be tested in accordance with the requirements of the corresponding product standards and the new test items specified in this standard, and should meet the corresponding requirements. Claim. When users have requirements, special tests are required.

The test items that are affected by plateau environmental conditions as specified in this standard can be tested under the following three test conditions.

a) Carry out under corresponding altitude environmental conditions;

b) Carry out under artificial simulated environmental conditions (simulation laboratory);

c) In a low altitude (below 2000m) environment, the influential test items are corrected by the method (see 8.3).

8.2 Test classification and items

The test of high prototype products is divided into four categories according to the corresponding product standards. type test, conventional test, sampling test and special test. test The inspection items shall be carried out in accordance with the requirements stipulated in the corresponding product standards.

8.3 Method of using correction factor

The test that the plateau environment has an impact on the product is in addition to the natural environment at the corresponding altitude point and artificial simulated environmental conditions (simulation laboratory)

In addition to carrying out, the method of correction coefficient can also be used for 8.4 and 8.5 tests.

8.4 Temperature rise test

According to the provisions of 7.2.2.1, the temperature rise limit value of indoor prototype electrical products is unchanged when used in plateau areas, so when the altitude of the test site is When the altitude of the place of use is different, the temperature rise limit value required by the test should be corrected as follows according to the altitude difference between the two.

---When the altitude of the test site is lower than the location of use, the temperature rise limit required by the test is the temperature rise limit specified by the corresponding product standard Value minus the correction value, see Table A.2 for the correction value;

---When the altitude of the test site is higher than the use site, the temperature rise limit value required by the test is the temperature rise value specified by the corresponding product standard plus The upper correction value, the correction value is shown in Table A.2.

If the altitude is lower than 2000m, no correction will be made.

According to the provisions of 7.2.2.2, outdoor high prototype electrical products should also consider the mutual influence of Table A.1 and Table A.2 for temperature rise test.

The temperature rise limit value required by the test should not exceed the specified value. If the drop in ambient temperature is greater than the increase in temperature rise, no correction is required.

The temperature rise test of high heating appliances (resistors, varistors) can be carried out in accordance with their product standards and technical conditions.

8.5 Dielectric performance test

Under plateau environmental conditions, the power frequency withstand voltage and shock withstand voltage test should comply with 7.2.3 of GB/T 14048.1-2012 and conventional products.

Product-related standards. When testing at different altitudes, the power frequency withstand voltage and impact withstand voltage can be carried out according to the correction coefficient specified in Table 2. test.

8.6 Critical DC load current test

This test item is a special test item.

For products that meet GB/T 14048.2-2020, the test should be carried out in accordance with the provisions of 8.3.9 in GB/T 14048.2-2020.

The test results should meet the corresponding requirements of GB/T 14048.2-2020.

Note: If the test conditions are restricted, the user shall negotiate with the manufacturer.

8.7 Short-circuit making and breaking capacity test

This test item is a special test item.

The test method for short-circuit making and breaking capacity is in accordance with the relevant product standards, and the test environment conditions should meet the conditions specified in 8.1.

The test results should meet the requirements of the relevant product standards.

Note 1.If the test conditions are restricted, the user and the manufacturer negotiate to resolve.

Note 2.For products that meet GB/T 14048.3-2017 Appendix D and GB/T 14048.4-2020 Appendix M, the user and the manufacturer shall negotiate.

8.8 Tripping characteristic test

For products with thermal tripping function, the test method of tripping characteristics shall be in accordance with the relevant product standards, and the test environmental conditions shall be in accordance with 8.1 conditions of.

The test results should meet the requirements of the relevant product standards.

8.9 Low temperature test

This test item is a type test.

Test according to the requirements of test Ab in GB/T 2423.1-2008, the test temperature is the lowest temperature of the corresponding altitude (see

Table 3), the duration is 16h. During the test, the sample is not connected to the load.

After the test, after the test product is restored under standard atmospheric conditions, check the appearance of the test product, there should be no damage that affects its use, and it should be able to be connected and divided. Break the rated current.