How to debug the distribution cabinet after installation?

After the installation of the distribution cabinet is completed, the debugging work is very important. The following are the specific steps of debugging:

First, the preparation work before debugging

Check equipment integrity: reconfirm whether the electrical components, instruments, switches and other equipment in the power distribution cabinet are completely installed, without omission, damage or looseness.

Cleaning the site: ensure that the environment around the distribution cabinet is clean and tidy, and there is no debris accumulation, so as not to affect the commissioning work and equipment safety.

Prepare debugging tools: such as multimeter, megger, oscilloscope and other electrical measuring tools, as well as commonly used tools such as wrench and screwdriver.

Familiar with drawings and technical data: Debuggers should be familiar with the electrical schematic diagram, wiring diagram and related technical specifications of the distribution cabinet, and make clear the debugging objectives and requirements.

Second, the appearance inspection

Check the cabinet: check whether the cabinet of the distribution cabinet is deformed, scratched and rusted, whether the cabinet door is flexible to open and whether the door lock is reliable.

Check wiring: check whether the wiring in the distribution cabinet is neat and standard, whether the color and number of wires meet the requirements, and whether the wiring terminals are fastened.

Check identification: confirm whether the identification on the power distribution cabinet is clear and accurate, including equipment name, serial number, function identification, etc.

Third, the insulation resistance test

Disconnect the power supply: Before the insulation resistance test, the power distribution cabinet must be disconnected from the external power supply to ensure that the equipment is in a safe state.

Select test instrument: use megger to test the insulation resistance of the electrical circuit in the distribution cabinet.

Test method: Test the main circuit and the control circuit respectively, connect the two test probes of the megger to the two ends of the tested circuit respectively, and shake the handle of the megger at the specified speed to read the insulation resistance.

Qualification standard: Generally speaking, the insulation resistance of the main circuit should be not less than 1MΩ, and the insulation resistance of the control circuit should be not less than 0.5MΩ. If the insulation resistance value is lower than the standard requirements, check whether there are problems such as damp and short circuit in the circuit, and deal with them accordingly.

Four, grounding resistance test

Select testing instrument: use grounding resistance tester to test the grounding system of distribution cabinet.

Test method: Connect the test probe of the grounding resistance tester to the grounding terminal and grounding electrode of the power distribution cabinet respectively, test according to the operating instructions of the tester, and read the grounding resistance value.

Qualification standard: the grounding resistance value should meet the requirements of local electrical codes, generally not more than 4Ω. If the grounding resistance exceeds the standard, check whether the connection of grounding system is good and whether the grounding electrode is buried in line with the requirements, and make corresponding rectification.

V. Electrical Performance Testing

Power check: check whether the power input of the distribution cabinet is normal and whether the voltage and frequency meet the requirements. You can use tools such as multimeter or oscilloscope to measure.

Switch operation test: test the operation of various switches in the distribution cabinet, including circuit breakers, disconnectors and contactors. Check whether the action of the switch is flexible and reliable, and whether the opening and closing instructions are correct.

Protection function test: test the protection function of the distribution cabinet, such as overload protection, short circuit protection, leakage protection, etc. You can check whether the protection device can act in time to cut off the fault circuit by simulating the fault situation.

Instrument calibration: check the instruments in the power distribution cabinet, such as voltmeter, ammeter and power meter. Calibrate the instrument with standard signal source or actual load to ensure the measurement accuracy of the instrument meets the requirements.

Six, system linkage debugging

Linkage with external equipment: If the distribution cabinet has linkage with other equipment or systems, the system linkage debugging should be carried out. Check whether the signal transmission between devices is normal and the linkage control is reliable.

Simulated operation test: under the actual load condition, the simulated operation test is carried out on the distribution cabinet. Observe the running state of the power distribution cabinet, and check whether the electrical parameters are normal, and whether there is abnormal heating and noise.

VII. Debugging Records and Reports

During debugging, all data and results of debugging should be recorded in detail, including insulation resistance value, grounding resistance value, electrical performance test data, system linkage debugging, etc.

According to the debugging record, write the debugging report. The debugging report shall include the purpose, method, process, result, existing problems and rectification measures of debugging.

The commissioning report shall be signed by the commissioning personnel and submitted to relevant departments for review and filing.

In a word, the debugging work after the installation of the distribution cabinet needs to be carried out in strict accordance with the specifications to ensure the safe and reliable operation of the equipment. In the process of debugging, if problems are found, they should be dealt with in time until the debugging results meet the requirements.