Home
Product Catalog
News
Contact Us

News 

News

Photovoltaic Storage | How to deal with PV system line faults

Publish Date 2022-12-16
In a PV system installation, the inverter has two sets of wires to be connected, one is the DC cable at the module end, which usually varies from one to two dozen sets. The second is the AC end, there are two types of single-phase and three-phase. The cables of the inverter, when wired, should be well marked and connected in order, if the lines are connected wrongly, the lighter the inverter does not work, the heavier the damage to the machine is possible. Before connecting, measure the voltage with a multimeter to avoid faults and also to analyse the cause of the fault from the monitoring end.

01 Reversed positive and negative terminals of the string

The PV module is connected to the inverter, as the module is some distance away from the inverter, an extension cable needs to be added, this extension cable needs to be made on site, the correct connection method is the female terminal on one side of the PV connector and the male terminal on the other side, so as to ensure that the positive and negative pole direction will not change, some novices will make the two connectors of the extension cable the same, if connected to the inverter, it will cause the positive and negative poles to be reversed, the impact of this situation depends on the The impact of this situation depends on the electrical structure of the inverter.

If only one string is connected in the opposite direction, the inverter will not start and the inverter indicator and screen will not light up. However, the inverter will not be damaged and will work normally if it is reconnected. If it is a two-way string, one way is connected to the right one and the other way is connected to the opposite one, the two-way string is equivalent to an internal short circuit, the component short circuit current is amplified by 15%, the fuse will not blow, the inverter DC voltage may only be a few volts, the inverter will not be damaged, the component will slowly burn out. If it is an MPPT multiplex string, one way is connected right and the other few are connected backwards, or one way is connected backwards and the other few are connected right, the string will be short-circuited internally and the current will join more than 2 times, if the inverter has a fuse, the fuse will fuse and the circuit will be broken, not causing a fire. If the fuse blows, the voltage at both ends of the fuse will be doubled, causing over-voltage at the DC end and the inverter will blow up.



If the positive and negative terminals of the string are reversed, the consequences will be more serious, for example, the inverter will blow up or the components will catch fire. If you are not very skilled, you can use a multimeter to measure the voltage first, remember to use the DC voltage gear, if the direction of the measured voltage and the inverter is right, then connect to the inverter.



02 Wrong connection of positive and negative terminals of the string

If the string has more than one input, such as PV1, PV2, PV3, a group of input has two positive and negative poles, sometimes the negative pole of PV1 may be connected to PV2, if the two strings are the same way MPPT, it is not affected, if not the same way MPPT, it will not form a circuit, the two strings connected to the wrong line will not work properly, the monitoring display voltage is not normal.

If the inverter does not detect the voltage of the string and shows zero, it means that the system is disconnected, possibly because one of the connectors in the middle of the PV string is disconnected, the inverter or DC bus box switch is not closed, the inverter PV fuse is blown, etc.



03 Wrong AC line connection


The inverter remote monitoring will report an "AC voltage out of range" fault, or "no mains connection". The following is an analysis of several cases of wrong connection.

(1) Three phase lines (A, B, C) sequence, there is no problem of wrong connection, because the grid-connected inverter has the function of automatically adjusting the phase sequence, before grid-connected power generation, it first takes power from the grid, detects the voltage, frequency, phase sequence and other parameters of the grid, and then adjusts its own parameters of power generation, and synchronizes with the grid electrical parameters before grid-connected power generation.

(2) The phase and zero wires are connected wrongly. A user connects phase A to zero N, then the inverter will report a grid voltage fault, the inverter will show a line voltage of 400V for phase A and 230V for phase B and C. The inverter will think the voltage is too low and will not start.


The inverter reports AC voltage over range warning, the voltage of each phase of the grid seen from the APP monitor, among which AC1 is normal, AC2 and AC3 voltage is low, after the field test, it is the phase line L1 and zero line N line connected to reverse, transfer the L1 phase line and zero line N line to each other, the inverter can return to normal.

Poor contact or damage to the AC switch will also cause the inverter to report an "AC voltage over range" fault. The AC switch at the back of the inverter will have a large internal resistance if the cable is not tightened or the switch is not of good quality due to long operation, which may cause the voltage to drop.






Home  |  Product Catalog  |  News  |  Contact Us  |  Sitemap  |  Mobile Version
  English     简体版     繁體版

Powered by DIYTrade.com  Build your FREE website !
Find Best Price For China Products !