Routine maintenance of photovoltaic power station
Confluence box
The confluence box is a collection of current equipment, mainly used in large and medium-sized photovoltaic systems, photovoltaic array module string number, output, must need a device to concentrate these output, so that it can be directly connected to the inverter. In solar photovoltaic power generation system, in order to reduce the connection between the solar photovoltaic cell array and the inverter, According to "SJT 11127-1997 Photovoltaic (PV) Power Generation System Overvoltage Protection - Guidelines" and "GB/T18479-2001 Ground photovoltaic (PV) Power generation System Overview and Guidelines" and the characteristics of the photovoltaic system, Corbett Technology can connect a certain number of photovoltaic cells with the same specifications and pv wire in series. Composed of a series of photovoltaic, and then a number of photovoltaic series parallel access to the photovoltaic surge protection box, in the photovoltaic surge protection box after the convergence, through the DC circuit breaker output, and photovoltaic inverter matching use to form a complete photovoltaic power generation system, grid connection.
It can be connected to multiple solar photovoltaic arrays at the same time. The rated current of each channel can reach 10A and the maximum is 15A, which can meet the needs of different users. Each input is independently equipped with a solar photovoltaic DC high-voltage lightning protection circuit, with multi-level lightning protection functions, to ensure that lightning strikes do not affect the normal output of the photovoltaic array. The output end is equipped with a photovoltaic DC high-voltage lightning protection module, which can withstand the maximum lightning current of 80kA. High voltage circuit breaker, DC voltage value is not less than DC1000V, safe and reliable. With lightning recording function, it is convenient to know the invasion of lightning disaster. With current, voltage, electricity real-time display function, it is easy to observe the working condition. Protection level up to IP65, meet the requirements of outdoor installation. With remote monitoring function. The main structure of the confluence box is fuse, lightning protection device, DC circuit breaker (isolation switch), positive (negative) pole wiring board, current sensor, metering sample, communication board, etc.
The Photovoltaic surge protection box is equipped with photovoltaic special DC surge protection module, DC fuse and circuit breaker, and set up the working state indicator light, lightning counter. In order to facilitate users to timely and accurately grasp the working conditions of photovoltaic cells, remote communication monitoring devices are equipped to ensure the maximum effect of solar photovoltaic power generation system.
The main faults of the confluence box are as follows:
1. Burning of positive and negative fuses; the main reasons are:
a. The rated current of the fuse is smaller than the current connected to the PV series.
b. The positive and negative terminals of the cables connecting to the junction box are short-circuited or grounded.
c. Fuse burning caused by unqualified fuse quality.
d. The number of serial photovoltaic modules exceeds the design standard.
e. The cable of the PV module is improperly connected to the wiring terminal.
f. The MC4 head is improperly connected to the component.
2. Communication interruption, digital LCD tube without display; the main reasons are:
a. The communication cable is grounded, short-circuited, or disconnected.
b. The communication board is burned.
c. No communication power supply.
d. The 24V power supply voltage is lower than 20V.
e. Communication device 485 The serial port is faulty.
f. The communication device is faulty and has no power supply.
g. 485 Communication cables are improperly connected or connected in an incorrect way.
h. The background is not associated with the address or measurement point related to the junction box.
I. The site number of the convergence box is incorrectly set or repeated.
j. The grounding mode of the communications cable shielding cable is incorrect.
k. The communication line is interfered (the communication line is laid too close to the strong current line and is not laid according to the relevant laying standards).
l. The baud rate and dip resistance of the junction box are incorrectly set.
m. Communication line distance is too long, signal attenuation.
n. No terminal resistance is added to the junction box (exceeding 60m).
o. The configured number of junction boxes exceeds the actual number of connections.
3. The cable is grounded or short-circuited.
4. The DC circuit breaker in the condenser is tripped
Precautions for routine inspection of the confluence box
The photovoltaic surge protection condenser should be inspected once a month. During the inspection process, at least two people should be inspected according to the requirements of the safety regulations of the power plant. The main inspection is to check the appearance of the confluence box and whether the fixing bolts of the cabinet are loose. Surge protectors (surge protection devices), cables, and positive and negative terminals are abnormal. In the inspection also check the current of each branch, check whether the wiring is loose, wiring terminals and insurance base is discolored.
When checking to see whether the busbar in the confluence box discoloration; whether the bolts are fastened; whether the grounding is good; whether the circuit breaker in the cabinet is hot or not; test whether the fire blocking is qualified; when inspecting the circuit breaker, you must open the circuit breaker in the DC cabinet of the corresponding inverter. The busbar bolts in the confluence box are tightened once a year.
Colonization of inverts
I. Function and significance of contravariant colonization
Grid-connected inverter is an essential electrical equipment in photovoltaic power station, and also the core equipment in photovoltaic power generation system. The inverter converts the direct current (DC) generated by the photovoltaic array into the three-phase sinusoidal alternating current (AC), and outputs the electric energy that meets the requirements of the power grid. Inverter is the key equipment of energy conversion, its efficiency index and other electrical performance parameters will directly affect the power generation. The inverter meets the following requirements:
1. The power factor and power quality of grid-connected inverters should meet the requirements of the grid.
2. The rated power of the inverter should meet the requirements of the altitude, and the internal insulation and other electrical properties should meet the requirements.
The inverter uses solar module maximum power tracking technology (MPPT). Inverter has polarity back connection protection, short circuit protection, island effect protection, over temperature protection, AC over current and DC over current protection, DC bus over (low) voltage protection, power grid outage, power grid over and under voltage protection, power grid over and under frequency protection, photovoltaic array and inverter itself grounding detection protection and low voltage crossing function.
Ii. Inspection items
1. Ash accumulation degree of ventilation filter screen of inverter.
2. Check whether the meters in the DC cabinet of the inverter are normal, whether the circuit breaker is tripped, and whether the wires are loose, heated and discolored.
3. Check whether the ventilation condition and temperature detection device of the inverter are normal.
4. Whether the inverter is overheated.
5. Inverter lead and wiring terminals are loose, input and output wiring terminals have no damage and discoloration traces.
6. Check whether all parts of the inverter are properly connected.
7. Check whether the inverter is properly grounded.
8. Indoor dust of the inverter.
9. Check whether the inverter fan runs normally and the air duct is well ventilated.
10. Check whether the operating parameters of the inverter are correctly set.
11. Check whether the running indicator and sound of the inverter are normal.
12. Check whether the inverter fire seal is qualified and the rat proof plate is installed properly.
13. Check whether the inverter SPD works (green if normal).
14. Whether the parameters of the inverter are normal under the running state (whether the three-phase voltage and current are balanced).
15. Check whether the inverter runs in MPPT mode.
The main faults of the confluence box are as follows:
1. Burning of positive and negative fuses; the main reasons are:
a. The rated current of the fuse is smaller than the current connected to the PV series.
b. The positive and negative terminals of the cables connecting to the junction box are short-circuited or grounded.
c. Fuse burning caused by unqualified fuse quality.
d. The number of serial photovoltaic modules exceeds the design standard.
e. The cable of the PV module is improperly connected to the wiring terminal.
f. The MC4 head is improperly connected to the component.
2. Communication interruption, digital LCD tube without display; the main reasons are:
a. The communication cable is grounded, short-circuited, or disconnected.
b. The communication board is burned.
c. No communication power supply.
d. The 24V power supply voltage is lower than 20V.
e. Communication device 485 The serial port is faulty.
f. The communication device is faulty and has no power supply.
g. 485 Communication cables are improperly connected or connected in an incorrect way.
h. The background is not associated with the address or measurement point related to the junction box.
I. The site number of the convergence box is incorrectly set or repeated.
j. The grounding mode of the communications cable shielding cable is incorrect.
k. The communication line is interfered (the communication line is laid too close to the strong current line and is not laid according to the relevant laying standards).
l. The baud rate and dip resistance of the junction box are incorrectly set.
m. Communication line distance is too long, signal attenuation.
n. No terminal resistance is added to the junction box (exceeding 60m).
o. The configured number of junction boxes exceeds the actual number of connections.
3. The cable is grounded or short-circuited.
4. The DC circuit breaker in the condenser is tripped
Precautions for routine inspection of the confluence box
The photovoltaic surge protection condenser should be inspected once a month. During the inspection process, at least two people should be inspected according to the requirements of the safety regulations of the power plant. The main inspection is to check the appearance of the confluence box and whether the fixing bolts of the cabinet are loose. Surge protectors (surge protection devices), cables, and positive and negative terminals are abnormal. In the inspection also check the current of each branch, check whether the wiring is loose, wiring terminals and insurance base is discolored.
When checking to see whether the busbar in the confluence box discoloration; whether the bolts are fastened; whether the grounding is good; whether the circuit breaker in the cabinet is hot or not; test whether the fire blocking is qualified; when inspecting the circuit breaker, you must open the circuit breaker in the DC cabinet of the corresponding inverter. The busbar bolts in the confluence box are tightened once a year.
Colonization of inverts
I. Function and significance of contravariant colonization
Grid-connected inverter is an essential electrical equipment in photovoltaic power station, and also the core equipment in photovoltaic power generation system. The inverter converts the direct current (DC) generated by the photovoltaic array into the three-phase sinusoidal alternating current (AC), and outputs the electric energy that meets the requirements of the power grid. Inverter is the key equipment of energy conversion, its efficiency index and other electrical performance parameters will directly affect the power generation. The inverter meets the following requirements:
1. The power factor and power quality of grid-connected inverters should meet the requirements of the grid.
2. The rated power of the inverter should meet the requirements of the altitude, and the internal insulation and other electrical properties should meet the requirements.
The inverter uses solar module maximum power tracking technology (MPPT). Inverter has polarity back connection protection, short circuit protection, island effect protection, over temperature protection, AC over current and DC over current protection, DC bus over (low) voltage protection, power grid outage, power grid over and under voltage protection, power grid over and under frequency protection, photovoltaic array and inverter itself grounding detection protection and low voltage crossing function.
Ii. Inspection items
1. Ash accumulation degree of ventilation filter screen of inverter.
2. Check whether the meters in the DC cabinet of the inverter are normal, whether the circuit breaker is tripped, and whether the wires are loose, heated and discolored.
3. Check whether the ventilation condition and temperature detection device of the inverter are normal.
4. Whether the inverter is overheated.
5. Inverter lead and wiring terminals are loose, input and output wiring terminals have no damage and discoloration traces.
6. Check whether all parts of the inverter are properly connected.
7. Check whether the inverter is properly grounded.
8. Indoor dust of the inverter.
9. Check whether the inverter fan runs normally and the air duct is well ventilated.
10. Check whether the operating parameters of the inverter are correctly set.
11. Check whether the running indicator and sound of the inverter are normal.
12. Check whether the inverter fire seal is qualified and the rat proof plate is installed properly.
13. Check whether the inverter SPD works (green if normal).
14. Whether the parameters of the inverter are normal under the running state (whether the three-phase voltage and current are balanced).
15. Check whether the inverter runs in MPPT mode.