光伏发电是利用半导体界面的光生伏特效应而将光能直接转变为电能的一种技术。这种技术的关键元件是太阳能电池。太阳能电池经过串联后进行封装保护可形成大面积的太阳电池组件，再配合上逆变器，功率控制器等部件就形成了 光伏发电装置。太阳能光伏发电的优点是较少受地域限制，因为阳光普照大地;光伏系统还具有安全可靠、无噪声、低污染、无需消耗燃料和架设输电线路即可就地发电供电及建设同期短的优点。

光伏逆变器 作为一项电子产品，由众多元器件组成。逆变器又称电源调整器，根据逆变器在光伏发电系统中的用途可分为独立型电源用和并网用二种。根据波形调制方式又可分为方波逆变器、阶梯波逆变器、正弦波逆变器和组合式三相逆变器。对于用于并网系统的逆变器，根据有无变压器又可分为变压器型逆变器和无变变压器型逆变器。

光伏逆变器作为整个电站的检测中心，上对直流组件，下对并网设备，基本所有的电站参数都可以通过逆变器检测出来。一般逆变器只要在并网状态，监控显示的功率曲线为正常的“山”行，证明该电站运行稳定，如果出现异常，则可以通过逆变器反馈的信息检查电站配套设备健康状况。下面整理了一些光伏逆变器常见的故障原因分析与处理方法：

1、光伏逆变器屏幕没有显示

故障分析：没有直流输入，逆变器LCD是由直流供电的。

可能原因：

（1）组件电压不够。逆变器工作电压是100V到500V，低于100V时，逆变器不工作。组件电压和太阳能辐照度有关。

（2）PV输入端子接反，PV端子有正负两极，要互相对应，不能和别的组串接反。

（3）直流开关没有合上。

（4）组件串联时，某一个接头没有接好。

（5）有一组件短路，造成其他组串也不能工作。

解决办法：用完用表电压档测量逆变器直流输入电压。电压正常时，总电压是各组件电压之和。如果没有电压，依次检测直流开关，接线端子，电缆接头，组件等是否正常。如果有多路组件，要分开单独接入测试。如果逆变器是使用一段时间，没有发现原因，则是逆变器硬件电路发生故障，可以联系生产厂家售后。

2、光伏逆变器不并网，屏幕显示市电未接

故障现象：逆变器不并网，屏幕显示市电未接

故障分析：逆变器和电网没有连接

可能原因：

（1）交流开关没有合上。

（2）逆变器交流输出端子没有接上。

（3）接线时，把逆变器输出接线端子上排松动了。

解决办法：用万用表电压档测量逆变器交流输出电压，在正常情况下，输出端子应该有220V或者380V电压，如果没有，依次检测接线端子是否有松动，交流开关是否闭合，漏电保护开关是否断开。

3、屏幕显示PV电压高

故障分析：直流电压过高报警

可能原因：组件串联数量过多，造成电压超过逆变器的电压。

解决办法：因为组件的温度特性，温度越低，电压越高。单相组串式逆变器输入电压范围是100-500V，建议组串后电压在350-400V之间，三相组串式逆变器输入电压范围是250-800V，建议组串后电压在600-650V之间。在这个电压区间，逆变器效率较高，早晚辐照度低时也可发电，但又不至于电压超出逆变器电压上限，引起报警而停机。

4、屏幕显示PV绝缘阻抗过低

故障分析：光伏系统接地绝缘电阻小于2兆欧

可能原因：太阳能组件，接线盒，直流电缆，逆变器，交流电缆，接线端子等地方有电线对地短路或者绝缘层破坏。PV接线端子和交流接线外壳松动，导致进水。

解决办法：断开电网，逆变器，依次检查各部件电线对地的电阻，找出问题点，并更换。

5、屏幕显示输出漏电流过高

故障分析：漏电流太大

解决办法：取下PV阵列输入端，然后检查外围的AC电网。直流端和交流端全部断开，让逆变器停电30分钟以上，如果自己能恢复就继续使用，如果不能恢复，联系售后技术工程师。

6、屏幕显示市电电压超范围

故障分析：电网电压过高。电网阻抗增大，光伏发电用户侧消化不了，输送出去时又因阻抗过大，造成逆变器输出侧电压过高，引起逆变器保护关机，或者降额运行。

解决办法：

（1）加大输出电缆，因为电缆越粗，阻抗越低。

（2）逆变器靠近并网点，电缆越短，阻抗越低。 

It is a technology that directly converts light energy into electrical energy by using the photovoltaic effect at the semiconductor interface. The key component of this technology is the solar cell. After the solar cells are connected in series, they can be packaged and protected to form a large area of solar cell modules, and then combined with inverter, power controller and other components to form a photovoltaic power generation device. The advantage of solar photovoltaic power generation is that it is less restricted by region, because the sun shines on the earth; The photovoltaic system also has the advantages of safety and reliability, no noise, low pollution, local power generation and power supply without fuel consumption and power transmission lines, and short construction period.



As an electronic product, photovoltaic inverter is composed of multiple devices. Inverter, also known as power regulator, can be divided into independent power supply and grid connection according to the use of inverter in photovoltaic power generation system. According to the waveform modulation mode, it can be divided into square wave inverter, step wave inverter, sine wave inverter and combined three-phase inverter. The inverter used in grid connected system can be divided into transformer type inverter and non transformer type inverter according to whether there is transformer or not.



As the detection center of the whole power station, PV inverter can detect almost all power station parameters from DC components at the top and grid connected equipment at the bottom. Generally, as long as the inverter is in the grid connected state, the power curve displayed by monitoring is a normal "mountain" line, which proves that the power station operates stably. In case of any abnormality, the health status of the supporting equipment of the power station can be checked through the information fed back by the inverter. Here are some common fault analysis and treatment methods of PV inverter:



1. PV inverter screen is not displayed



Fault analysis: there is no DC input, and the inverter LCD is powered by DC.



Possible causes:



(1) Insufficient component voltage. The working voltage of the inverter is 100V to 500V. When it is lower than 100V, the inverter does not work. Module voltage is related to solar irradiance.



(2) The PV input terminal is connected reversely. The PV terminal has positive and negative poles, which should correspond to each other and cannot be connected reversely with other groups in series.



(3) The DC switch is not closed.



(4) When the components are connected in series, one of the connectors is not connected properly.



(5) One component is short circuited, causing other strings to fail to work.



Solution: measure the DC input voltage of the inverter with the voltmeter after use. When the voltage is normal, the total voltage is the sum of the component voltages. If there is no voltage, check whether the DC switch, wiring terminal, cable connector, components, etc. are normal. If there are multiple components, separate and separate access test shall be conducted. If the inverter is used for a period of time and no cause is found, the inverter hardware circuit is faulty. You can contact the manufacturer for after-sales service.



2. The PV inverter is not connected to the grid, and the screen shows that the mains power is not connected



Fault phenomenon: the inverter is not connected to the grid, and the screen shows that the mains power is not connected



Fault analysis: inverter and power grid are not connected



Possible causes:



(1) The AC switch is not closed.



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



(3) During wiring, the upper row of inverter output terminals is loosened.



Solution: measure the AC output voltage of the inverter with the voltage gear of the multimeter. Under normal conditions, the output terminal should have 220V or 380V voltage. If not, check whether the wiring terminal is loose, whether the AC switch is closed, and whether the leakage protection switch is disconnected.



3. The screen shows that the PV voltage is high



Fault analysis: high DC voltage alarm



Possible cause: too many components are connected in series, causing the voltage to exceed the voltage of the inverter.



Solution: because of the temperature characteristics of the components, the lower the temperature, the higher the voltage. The input voltage range of single-phase series inverter is 100-500v. It is recommended that the voltage behind the series is 350-400v. The input voltage range of three-phase series inverter is 250-800v. It is recommended that the voltage behind the series is 600-650v. In this voltage range, the inverter has high efficiency and can generate power in the morning and evening when the irradiance is low, but the voltage will not exceed the upper limit of the inverter voltage, causing alarm and shutdown.



4. The screen shows that the PV insulation impedance is too low



Fault analysis: the grounding insulation resistance of photovoltaic system is less than 2 megohm



Possible causes: short circuit of wires to the ground or damage of insulation layer in solar modules, junction boxes, DC cables, inverters, AC cables, terminals and other places. The PV wiring terminal and AC wiring housing are loose, resulting in water ingress.



Solution: disconnect the power grid and inverter, check the resistance of each component wire to the ground in turn, find out the problem point and replace it.



5. The screen shows that the output leakage current is too high



Fault analysis: the leakage current is too large



Solution: remove the PV array input terminal, and then check the peripheral AC power grid. Disconnect all DC and AC terminals, and power off the inverter for more than 30 minutes. If you can recover, continue to use it. If you can't recover, contact the after-sales technical engineer.



6. The screen shows that the mains voltage is out of range



Fault analysis: the grid voltage is too high. As the grid impedance increases, the photovoltaic power generation user side cannot digest it. When it is transmitted out, the output side voltage of the inverter is too high due to excessive impedance, causing the inverter protection shutdown or derating operation.



terms of settlement:



(1) Increase the output cable because the thicker the cable, the lower the impedance.



(2) When the inverter is close to the parallel node, the shorter the cable, the lower the impedance.