Basic requirements for routine testing of photovoltaic DC circuit breakers
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- Author：FMELEC
- Source：本站
- Release Time：2021-10-29
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Details
1. In all tests, the wiring of each pole of the PV DC circuit breaker shall be in accordance with the manufacturer's instructions. Samples should be selected and tested in accordance with the "Terminal Unmarked Power/Load" column of the data sheet.
Note: The tests required by this standard do not exclude the additional tests required for circuit breakers installed in complete sets, such as tests according to GB/T7251.
2. Unless agreed by the manufacturer, each test procedure shall be carried out on a new (or group of) clean circuit breaker. The number of samples and test conditions (such as the setting value of the overload release, the connection method of the terminals) for each test procedure are listed in the data sheet according to the parameters of the circuit breaker.
3. Additional requirements are given in the relevant clauses as needed.
4. Unless otherwise specified, the test is carried out on the circuit breaker with the maximum rated current for a given frame class, and is considered to include all rated currents of that frame class.
5. In the case of one or more structural sections (see 2.1.2 and 7.1.5 of GB/T 14048.2-2008) in a frame level, additional test samples should be added and tested according to the table.
6. Unless otherwise specified, the short-circuit release shall be set at the maximum value (time and current) for all tests.
7. All main parts of the tested circuit breaker shall conform to the typical structural design of the circuit breaker.
8. Unless otherwise specified, the test should be carried out under the same current type and the same number of poles as expected operating conditions.
9. If the mechanism is electrically controlled, the minimum voltage specified in 7.2.1.1. of GB/T14048.2-2008 shall be applied. In addition, the electric control mechanism shall be powered by a circuit breaker dedicated control circuit equipped with a switchgear. It should also be verified that the circuit breaker operates correctly under the above conditions without load.
10. The circuit breaker related to manual operation (see 2.4.12 of GB/T14048.1-2012) should be operated at a speed of 0.1 (1±25%) m/s. Measure while the circuit breaker is operating the device. For knob-operated circuit breakers, the angular velocity of the actuating device shall comply with the above provisions.
11. The circuit breaker under test shall be completely installed on its own bracket or an equivalent bracket.
12. The circuit breaker should be tested in free air.
13. If the circuit-breaker can be used in the specified separate enclosure and has been tested in free air, each of the following additional tests shall be performed using a new sample in the minimum enclosure specified by the manufacturer:
a) According to the provisions of 9.3.5, at the maximum value of Ue and the corresponding I
cu, the release is set at the maximum value (see Note a in Table 5) for the test;
b) According to the general test conditions of the circuit breaker with the maximum value of Ith specified in 9.3.2.5, the test is carried out under the agreed closed thermal current Ithe (see 4.3.2.2 of GB/T 14048.2-2008). The temperature rise should meet the requirements of 7.2.2 of GB/T14048.2-2008, but the terminal temperature rise should not exceed 70K.
Test details, including enclosure dimensions, shall be recorded in the test report.
Note: Separate enclosure refers to an enclosure designed and dimensioned to accommodate only one circuit breaker.
However, if the circuit breaker can be used in the specified separate enclosure and has passed the test in the minimum enclosure specified by the manufacturer, then the test in free air need not be carried out, provided that the enclosure is bare metal and uninsulated. Details including enclosure dimensions shall be recorded in the test report.
For the test in free air, short-circuit test (8.3.4.1, 8.3.5.2, 8.3.6.4, 8.3.7.1, 8.3.7.5, 8.3.7.6 and 8.3.8.3 of GB/T14048.2-2008) and Short-time withstand current test (8.3.6.2 and 8.3.8.2 of GB/T 14048.2-2008), if applicable, a metal mesh plate shall be placed on each side of the circuit breaker according to the manufacturer's instructions, the specific details, including The distance from the circuit breaker to the metal mesh plate shall be stated in the test report.
14. The characteristics of metal mesh are as follows:
- Structure: woven metal mesh or perforated metal sheet or drawn metal mesh;
——The ratio of the opening area to the total area: 0.45~0.65;
——The size of the hole: not more than 30mm2;
——Surface treatment: bare or plated metal;
--- Resistance: should be included in the calculation of the expected fault current of the fusible element circuit [see 8.3.4.1.2.d) in GB/T 14048.1-2012], the value of which is the furthest possible from the arc spray on the metal mesh point measured.
15. The tightening torque applied to the terminal screws shall comply with the manufacturer's instructions [see 6.1e)].
16. Repair or replacement of parts is not allowed.
Sometimes for the convenience of the test, it is feasible to increase the severity of the test (for example, using a higher operating frequency to shorten the test period), but it is not allowed to do so without the consent of the manufacturer.
The above are more detailed precautions related to the routine test of photovoltaic DC circuit breakers. I hope you can follow the above instructions and labels, which can greatly reduce the accident rate of circuit breaker products.
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