Commissioning of PV strings and tracking systems

Before the equipment and system are commissioned, the installation work should be completed and accepted. All decoration work should be completed and cleaned up. If special facilities such as air conditioners or ventilation devices are installed, they shall be installed and put into operation. The work that cannot be carried out or affects the safety of operation after receiving electricity shall be completed. The commissioning unit and personnel shall have the corresponding qualifications and pass the inspection. When using a multimeter to measure, you must ensure that the multimeter gear and range are correct.

1. PV string debugging

The following conditions must be met before the PV string is commissioned: ① Before the PV module is commissioned, all modules should be connected in parallel according to the number and model of the design documents. ②The polarity of the anti-reverse diode in the combiner box should be correct. ③The wiring of each loop cable in the combiner box is completed, and the marking is clear and accurate. ④ Commissioning personnel should have corresponding electrician qualifications or employment certificates and be equipped with corresponding labor protection articles. ⑤ Make sure that the fuses of each circuit are in the off position. ⑥ The grounding of the combiner box and the internal lightning protection module should be firm, reliable, and well connected. ⑦The monitoring circuit should have debugging conditions. ⑧The irradiance should be tested under the condition of more than 700W/m2, and the minimum should not be lower than 400W/m2.

The debugging and testing of PV strings should meet the following requirements: ① The polarity of PV strings tested in the combiner box should be correct. ②The voltage deviation between the same strings tested at the same time should not be greater than 5V. ③ The temperature of the string cables should be free from abnormal conditions exceeding normal temperature, so as to ensure that the cables are not short-circuited and damaged. ④When directly testing the short-circuit current of the string, it should be operated by professional certified personnel and take corresponding protective measures to prevent arcing. ⑤ In the case of grid-connected electric power generation, use a clamp multimeter to detect the string current, and there should be no abnormal fluctuation or difference in the current between the same strings. ⑥ Before the inverter is put into operation, all combiner boxes in the inverter unit should be tested and put into operation. ⑦ After the PV string test is completed, the record should be filled in according to the prescribed format.

After the inverter is put into operation, the switching sequence of PV strings in the combiner box should meet the following requirements:

①When the main switch of the combiner box has the function of arc breaking, its switching on and off should be carried out according to the following steps. a. Put in the small switch or fuse of the PV string first, and then put in the main switch of the combiner box. b. Exit the main switch of the combiner box first, and then exit the small switch or fuse of the PV string. ②The total output of the combiner box adopts a fuse. When the switch of the branch circuit photovoltaic string has the arc breaking function, its switching on and off should be carried out according to the following steps: (a) First put in the total output fuse of the combiner box, and then put in the small switch of the photovoltaic string. (b) Exit all PV string small switches in the box first, and then exit the total output fuse of the combiner box. ③ When fuses are used for the total output of the combiner box and the PV strings in the branch circuits, the inverter should be disconnected before switching on and off the fuses. The monitoring function of the combiner box should meet the following requirements: ① The communication address of the monitoring system should be correct, with good communication and anti-interference ability. ②The monitoring system should accurately reflect the current change of each PV string in the combiner box in real time.

Read more: Solar cell module installation

2. Tracking system debugging

If it is a tracking grid-connected power station, the following conditions should be met before the tracking system is debugged: ① The tracking system should be firmly and reliably fixed to the foundation; the grounding should be good. ②The cables connected to the rotating parts should be fixed firmly and have appropriate reserved length. ③There should be no obstacles within the rotation range.

In manual mode, commands are issued to the tracking system through man-machine interface, etc. The tracking system should meet the following requirements: ① The action direction of the tracking system should be correct; the transmission device and rotating mechanism should be flexible and reliable, and there should be no stuck phenomenon. ②The maximum angle of tracking system tracking should meet the technical requirements. ③The limit position protection should be reliable.

Before debugging in automatic mode, the following conditions should be met: ①The debugging should be completed in manual mode. ②For the tracking system that adopts the active control method, the accuracy of the initial conditions should also be confirmed.

In the automatic mode, the tracking system should meet the following requirements: ① The tracking accuracy of the tracking system should meet the technical requirements of the product. ② When the wind speed exceeds the normal working range, the tracking system should quickly take shelter from the wind; when the wind speed weakens to the normal working range, the tracking system should return to the correct tracking position within the set time. ③ The tracking system should be able to automatically return to the horizontal position or sleep state at night, and turn off the power supply. ④ The intermittent tracking system is adopted, and the motor operation mode should meet the requirements of technical documents. ⑤ The tracking system using passive control method should be able to track normally under low light conditions, and should not be disturbed by light to cause erroneous actions.

The monitoring function debugging of the tracking system should meet the following requirements: ① The communication address of the monitoring system should be correct, with good communication and anti-interference ability. ②The monitoring system should accurately reflect the running status, data and various fault information of the tracking system in real time. ③ The tracking system with remote control function should respond to remote operation in real time, and the action is accurate and reliable.

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