GB/T 29318-2024Electric energy metering for off-board chargers of electric vehicles (English PDF)

4.2 Functions

4.2.1 Metering function The charger has the following functions.

4.2.2 Billing function The charger shall have the function of calculating the billable amount based on time, electric energy and rate, etc.

4.2.3 Rate period setting function The charger has the following functions.

4.2.4 Time adjustment function The charger shall have a time adjustment function. In addition, it is prohibited to adjust the time during the charging process.

4.2.5 Information recording function

4.2.6 Clear function The charger has the following functions.

4.2.7 Display function

4.2.7.1 Basic requirements The charger shall have a display function that allows display on the machine body or other carriers.

4.2.7.2 Display digits and resolution The display digits and resolution of the charger satisfy the following requirements.

4.2.7.3 Charging display

4.2.8 Charging receipt function The charging receipt function of the charger satisfies the following requirements.

4.2.9 Consistency requirements If the charger has multiple human-machine interaction modes, all information related to metering and billing shall be consistent at the end of charging.

4.2.10 Software protection function

4.2.10.1 Prevention of mis-operation The charger shall have a software protection function that minimizes the possibility of mis- operation.

4.2.11 Other functions During the charging process, if the charger cannot normally perform billing, the current charging, metering and billing shall be immediately stopped, and the metering and billing value shall be stored; after the above-mentioned functions are restored, metering and billing shall be re-started.

4.3 Requirements for Complete Machine

4.3.1 Connection point location The connection point location of the charger satisfies the following requirements.

4.3.2 Nameplate The charger shall have a nameplate, and the nameplate identification shall include the following meter-related information. If there are multiple charging interface outputs, the maximum current and minimum current of each channel shall be marked. If each channel is not separately marked, it is the same by default.

4.3.3 Measurement range The measurement range of the charger shall comply with the following requirements.

4.3.4 Accuracy requirements

4.3.5 Pulse constant The relation between the number of electric energy pulses output by the charger test and the change in electric energy indicated by the display shall be consistent with the pulse constant marked on the nameplate.

4.3.6 Error variation At the same test point of the charger, the absolute value of the maximum error change between adjacent test results shall not exceed 1/5 of the maximum allowable error shown in Table 1 and Table 2.

4.3.7 Clock time error For chargers with time-sharing billing function, the clock time error of the chargers shall not exceed 5 seconds.

4.4 Requirements for metering module The shell of the metering module shall be able to be sealed. Only after the seal is broken is it possible to access the internal components of the module. For the metering module, which is an electric energy meter plus a supporting sensor device, the electric energy meter and sensor device shall be respectively and independently sealed.

5.4 Accuracy Test

5.4.1 General requirements Under the test reference conditions specified in Table 4, compare the electric energy values simultaneously determined by the calibration device and the charger under test, so as to determine the basic error of the charger under test.

5.4.2 Basic error test under reference voltage During the test, the charger applies the reference conditions specified in Table 4 other than current. The current test points shall include the minimum current and maximum current marked on the charger nameplate. Adopt the method specified in

5.4.1 to test the basic error of the charger.

5.4.3 Basic error test under reference current During the test, the charger applies the reference conditions specified in Table 4 other than voltage. The voltage test points shall include the minimum voltage and maximum voltage marked on the charger nameplate. Adopt the method specified in

5.4.1 to test the basic error of the charger. Check whether the test results comply with the provisions of 4.3.4.2.

5.4.4 Self-heating effect test During the test, set the charger to operate at the rated power and maximum output current, and immediately carry out the test on the error of electric energy metering. Then, at an interval of no more than 1 s, accurately draw the error change curve as a function of time. This test is conducted for at least

0.5 h, and in any case, the percentage error of the accuracy within 20 min does not change by more than 0.2% (Level-1 and Level-2). Calculate the change value before and after the error stabilizes.

5.4.5 Electromagnetic compatibility test During the test, under the test reference conditions specified in Table 4, select (Umin + Umax)/2, 0.5Imax load point to test the basic error. Then, in accordance with the requirements of

7.2 in GB/T 18487.2-2017, conduct tests on the external power frequency magnetic field, radio frequency electromagnetic field radiation, conducted disturbance induced by radio frequency field, and electrical fast transient pulse. During each test, the basic error is tested at the same load point.

5.5 Pulse Constant Test During the test, under the test reference conditions specified in Table 4, record the electric energy value displayed by the charger and the output pulse number of the test output within a time interval. The error ek is determined by Formula (6).

5.6 Error Variation Test During the test, under the test reference conditions specified in Table 4, the charger is tested repeatedly 3 times at the same test point. Calculate the maximum absolute value of the difference between adjacent test results.

5.8 Climate and Environmental Impact Test During the test, under the test reference conditions specified in Table 4, the charger is respectively subjected to high-temperature test, low-temperature test, alternating heat and humidity test. The test methods are as follows:

6.2 Inspection Items

6.2.1 Exit-factory inspection The manufacturer shall test the newly produced chargers in accordance with the inspection items specified in Table B.1 of Appendix B. After the chargers pass the inspection, the manufacturer shall issue an inspection certificate.

6.2.2 Type inspection Type inspection shall be carried out by a testing institution with relevant qualifications. Tests shall be carried out in accordance with the inspection items specified in Table B.1.When one of the following circumstances occurs, type inspection of the chargers shall be performed.

6.2.3 Acceptance inspection The acceptance inspection shall be covered by the clients themselves or entrusted to a testing institution with relevant qualifications. In addition, the inspection shall be carried out in accordance with the following procedures.