What should I do if 10KW 96V Off Grid Solar PV Systems does not work in rainy days?

The 10KW off Grid Solar system in my home has been in use for more than two years. Recently, I met a strange thing. When it rains, the photovoltaic system does not work.  
 
10kW off Grid Solar system analyze faults  
When it rains and the air is humid, it is easy to leak electricity, indicating that the components, cables or live parts of the 10kW off grid solar system have insulation damage.  It is generally manifested as low insulation impedance failure of inverter or leakage protection switch trip. Once grounding failure occurs in photovoltaic modules, cables, connectors, switches and other equipment, it will not only lead to the failure of grid-connection of 10kW off grid solar system power station, affecting power generation.  In serious cases, the entire 10kW off grid Solar system will fail or cause casualties.  Therefore, the insulation to the ground needs to be detected before the photovoltaic inverter runs to prevent electric shock.  

 
The inverter itself has insulation fault and leakage current detection. When the system fails and the insulation value is lower than the set value of the inverter, the inverter will start the fault alarm program until the shutdown. If the inverter detection system has problems, or the alarm threshold is raised, the leakage current protection switch of the AC part will act.  
 
Cause of the 10kw off grid solar system fault  
 
Low INSULATION impedance of the DC part: The insulation impedance refers to the detection of the DC part of the PHOTOVOLTAIC system, including the components and DC cables. If the inverter detects that the insulation impedance of the positive or negative poles of the components is too low to the ground, it indicates that the insulation impedance of the cables or components on the DC side is abnormal.  Low insulation resistance is a common fault photovoltaic system, component, dc cable, connector break, insulation aging can produce low insulation resistance, dc cable crossing the bridge, due to the edge of the metal bridge might be agnail, in the process of thread, it is possible to put the outer insulation of the cable skin damage, and cause of leakage.  
 
Ac leakage current, residual current, the leakage current is also called the square the causes is parasitic capacitance between pv systems and the earth, when the parasitic capacitance - pv systems - circuit is formed between the grid, the pv system without transformer, the loop impedance is relatively small, common mode voltage in photovoltaic system is formed on the parasitic capacitance between the earth and the larger the common-mode current, the leakage current.  
 
Dc insulation fault alarm threshold is 50 k Ω, leakage current fault threshold is 300 ma, so when the dc part insulation damage occurs, will be submitted to the insulation impedance, inverter downtime, unless special large dc cable breakage, generally do not quote leakage failure, when there is leakage current inverter fault, general examination inverter and internal communication cable section.  
 
Cause of the 10kw off grid solar system failure  
Construction factors:  This situation is generally common, in many cases within the past six months after the construction completion grid fault period, main relation with the construction quality is bigger, such as in the construction process of inverter dc into the wire cable is unqualified, insulation performance is low, the man-made damage or join terminal does not make the water protection, are likely to cause dc grounding phenomenon,  The number of on-site insulation problems can reflect the construction quality of the project to a certain extent.  
 
Environmental factors: Mainly with the application environment has a great impact, only in rainy days such a fault alarm situation is more often, or the installation environment is humid for a long time, such as the common fishing light complementary project, corresponding measures should be taken for this situation.  
 
10kW off Grid Solar system  
 
Rely on the inverter by series of screen: if the inverter dc side for multipath access to the given method can be used to test the components, inverter dc side only keep a list of components, check to see if the inverter after boot continue to report errors, if you don't continue to report errors, then connect the components of the insulation performance is good, if continue to report errors, then is likely to be the string component insulation does not conform to the requirements.  
 
Use a multimeter for each route:  Inverter ac/dc disconnect all cases, pull the access of each string into line, using a multimeter is the cathode respectively to measure the voltage inverter, to check whether there is a difference between each string, first, whether there is voltage to directly to 0, or close to zero, and compared with the normal operation of the inverter, if this method is unable to determine, need further testing.  

 
On-site inspection components of dc cable wiring of: first of all, part of the reason of abnormal insulation impedance is dc cable breakage cause, including the components, the cables between the components to the inverter, the cables between the cable and especially the corner didn't wear tube open laying of cables, all need to carefully check the cable to see if there is any breakage.  Secondly, the photovoltaic system is not well grounded, including the module grounding hole is not connected, the module pressure block is not in good contact with the bracket, and some tributaries of the cable casing water, will lead to low insulation impedance.  
 
Use a shaking meter or other professional insulation equipment for serial detection: in the case of no light and no electric cable, use a shaking meter to measure the insulation resistance of the positive and negative poles to the ground of the component in serial, and the impedance should be greater than the threshold requirements of the insulation resistance of the inverter.