Low temperature test of electric energy meter (based on GB/T17215/IEC62059 standard)

1、 The purpose of the experiment is to assess the measurement stability and functional integrity of the electric energy meter under low-temperature extreme working conditions, and to determine whether there are permanent faults or deterioration of the electric energy meter under stress at low temperatures.

2、 Reference standard GB/T17215.9321-2016 Reliability of electrical measuring equipment Part 321: Durability - Test specification for stability of metrological characteristics at high temperatures (same method for low temperature part)

3、 Test Conditions 3.1 Test Sample Status Packaging: Unpackaged Working Status: During the test, the sample meter should be in working condition (with reference voltage, reference current, or no load) 3.2 Environmental Conditions Select the corresponding test temperature according to the type of environment in which the energy meter is used: Phenotype Test Temperature Temperature Allowable Deviation Test Time

Temperature change rate: not greater than 1 ℃/min (both heating and cooling are not less than 1 ℃/min) 3.3 Electrical conditions Application of reference voltage (Un) Current circuit can adopt no-load or reference current (row standard or production standard)

4、 Experimental steps

4.1 Before the initial measurement experiment begins, measure the basic error of the tested meter under reference conditions (23 ℃± 2 ℃) and record the initial data. 4.2 Cooling: Place the sample table in the low-temperature test chamber and cool it down to the required temperature for low-temperature testing at a cooling rate of no more than 1 ℃/min at -25 ℃ or -40 ℃. After the low-temperature exposure temperature stabilizes, maintain the corresponding time according to the phenotype requirements. The sample meter is continuously powered on during the period. After the heating test is completed, heat up at a rate not exceeding 1 ℃/min to the reference temperature (23 ℃± 2 ℃). 4.5 Recovery and Testing Sample Table: After sufficient time (generally not less than 4 hours, subject to product standards) for reheating under reference conditions, perform appearance inspection: shell, terminals, and display are not damaged, cracked, or brittle. Function inspection: basic functions such as display, buttons, and communication are normal. Error inspection: basic errors under reference conditions are re measured and compared with initial errors;

5、 Qualification assessment

After the experiment, the electric energy meter meets the following conditions: no damage: no mechanical damage, no breakdown, no condensation short circuit or other damage to the shell and components inside the meter; Information remains unchanged: Factory settings, setting information, and other content are not subject to unexpected changes; Normal function: Basic functions (measurement, display, communication, etc.) are working normally; Error qualified: The basic error is within the allowable range of the product technical conditions, and the error variation meets the requirements of relevant specifications.

6、 Attention to work status: Low temperature testing must be conducted in an energized state, otherwise the impact of low temperature on measurement performance cannot be assessed, which is the biggest difference from the user's original manuscript. Anti condensation treatment: During the process of raising the temperature of the test chamber after the low-temperature test, attention should be paid to preventing condensation. The humidity can be controlled in the test chamber, and sufficient drying period can also be provided for the meter. Time difference of outdoor watches: The test temperature of outdoor watches will be lower (-40 ℃), but the test time will be even shorter (16 hours). This is a standard assessment of the differences in different usage scenarios - outdoor watches assess the ability to withstand extremely low temperatures, rather than long-term use. Recovery time: Sufficient recovery time should be given after cooling, the sample temperature should be stable, and the condensation should be completely evaporated before testing. Attention to protection: Wear anti freezing gloves to prevent frostbite when conducting low-temperature testing and layout.