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Distributed PV power plant common faults

Author: Source: Datetime: 2016-11-17 17:26:10

Failure phenomenon: the inverter screen does not show

 

1.1 Fault analysis: there is no DC input, the inverter LCD is supplied by DC power supply.

 

Possible causes:

(1) the component voltage is not enough. Inverter operating voltage is 100V to 500V, less than 100V, the inverter does not work. The voltage components and solar irradiance.

(2) PV input terminals, PV terminals have positive and negative poles, to each other, can not be connected with the other group.

(3) the DC switch is not closed.

(4) when the component is connected in series, a connector is not connected.

(5) there is a short circuit, causing the other groups can not work.

 

Solution: using a universal meter voltage profile to measure the DC input voltage of the inverter. When the voltage is normal, the total voltage is the sum of all the components. If there is no voltage, in order to detect the DC switch, terminal, cable connectors, components, etc. is normal. If there are multiple components, separate access to the test.

 

If the inverter is used for a period of time, there is no reason to find, then the inverter hardware circuit failure, please contact my company.

 

1.2, fault phenomenon: the inverter is not connected.

 

Fault analysis: the inverter and the grid are not connected.

 

Possible causes:

(1) the AC switch is not closed.

(2) the inverter AC output terminal is not connected.

(3) the connection, the output terminals on the loose.

Solution: use a multimeter measuring voltage inverter AC output voltage, under normal circumstances, there should be a 220V or 380V output terminal voltage, if not, turn detection terminal is loose, the AC switch is closed, the leakage protection switch is disconnected.

 

1.3, PV overpressure:

 

Fault analysis: DC voltage is too high alarm

 

Possible reasons: the number of components in series is too much, resulting in voltage than the inverter voltage.

 

Solution: because of the temperature characteristics of the components, the lower the temperature, the higher the voltage. Single phase series inverter input voltage range is 100-500V, the proposed group after the voltage between 350-400V, three-phase series inverter input voltage range is 250-800V, the proposed group after the voltage between 600-650V. In the range of the voltage inverter, high efficiency, low irradiance can also power sooner or later, but not beyond the voltage inverter voltage limit, causing alarm and shutdown.

 

1.4, isolation fault:

 

Fault analysis: solar power generator system on the ground insulation resistance is less than 2 m.

 

Possible reasons: solar module, junction box, DC cable, inverter, AC cable, wiring terminals and other places there are wires to the ground short circuit or insulation layer damage. PV wiring terminals and AC wiring shell loose, leading to water.

 

Solution: disconnect the power grid, the inverter, in turn to check the resistance of the parts of the wire to the ground, to identify the point of the problem, and to replace .


 Distributed PV power


1.5, leakage current fault:

 

Fault analysis: leakage flow is too large.

 

Solution: remove the PV array input, and then check the external AC power grid.

 

DC side and AC side all off, so that the inverter power outage for more than 30 minutes, if they can resume to continue to use, if not restored, contact technical engineer.

 

1.6 Grid fault:

 

Fault analysis: power grid voltage and frequency is too low or too high.

 

Solution: use a meter to measure the power grid voltage and frequency, if exceeded, waiting for the power grid to return to normal. If the grid is normal, fault detection circuit board, power inverter, DC side and AC side please disconnect all power inverter, for more than 30 minutes, if you can restore it to continue to use, if not restored, contact customer service engineer.

 

1.7, inverter hardware failure: divided into recoverable and non recoverable failure

 

Fault analysis: inverter circuit board, detection circuit, power circuit, communication circuit, etc..

 

Solution: the inverter hardware failure, please put the DC side and AC side of inverter power disconnect all, let more than 30 minutes, if you can restore it to continue to use, if not restored, contact customer service engineer.


1.8, the system output power is small: can not reach the desired output power

 

Possible reasons: there are many factors that affect the output power of solar backup generator system, including the solar radiation, the tilt angle of the solar cell module, the dust and the shadow block, the temperature characteristic of the component.

 

System power is too small due to improper installation of the system. Common solutions are:

 

(1) before the installation, to detect the power of each component is sufficient.

(2) according to the first chapter, the installation angle and orientation of the components are adjusted;

(3) to check whether the components have shadows and dust.

(4) detection of the voltage range of the component in series, the voltage is too low system efficiency will be reduced.

(5) before the installation of a series of multi group, check the open circuit voltage of the group, the difference is not more than 5V, if the voltage is not found, to check the line and connectors.

(6) when it is installed, it can be accessed in batches, each group is connected with the power of each group, and the difference between the power of the group is not more than 2%.

(7) install local ventilation is not smooth, the inverter heat did not spread out, or directly in the sun exposure, caused by high temperature of inverter.

(8) the inverter has a dual channel MPPT access, with only 50% of the total power per input power. In principle, each design and installation of the power should be equal, if only connected to the MPPT terminal, the output power will be reduced by half.

(9) bad contact cable cable wire diameter is too small, too long, a voltage loss, resulting in loss of power.

(10) the capacity of the grid connected AC switch is too small, which can not reach the output of the inverter.

 

2.9, AC side over voltage

 

Grid impedance is too large, solar generator user side can not digest, and when the transmission out of the impedance too large, resulting in the output voltage of the inverter side is too high, causing the inverter to protect the shutdown, or reduce the amount of operation.

 

Common solutions are:

(1) increase the output of the cable, because the cable is thicker, the lower the impedance.

(2) the inverter is close to the network, the shorter the cable, the lower the impedance.

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