光伏發(fā)電是利用半導(dǎo)體界面的光生伏特效應(yīng)而將光能直接轉(zhuǎn)變?yōu)殡娔艿囊环N技術(shù)。這種技術(shù)的關(guān)鍵元件是太陽能電池。太陽能電池經(jīng)過串聯(lián)后進行封裝保護可形成大面積的太陽電池組件，再配合上逆變器，功率控制器等部件就形成了 光伏發(fā)電裝置。太陽能光伏發(fā)電的優(yōu)點是較少受地域限制，因為陽光普照大地;光伏系統(tǒng)還具有安全可靠、無噪聲、低污染、無需消耗燃料和架設(shè)輸電線路即可就地發(fā)電供電及建設(shè)同期短的優(yōu)點。

光伏逆變器 作為一項電子產(chǎn)品，由眾多元器件組成。逆變器又稱電源調(diào)整器，根據(jù)逆變器在光伏發(fā)電系統(tǒng)中的用途可分為獨立型電源用和并網(wǎng)用二種。根據(jù)波形調(diào)制方式又可分為方波逆變器、階梯波逆變器、正弦波逆變器和組合式三相逆變器。對于用于并網(wǎng)系統(tǒng)的逆變器，根據(jù)有無變壓器又可分為變壓器型逆變器和無變變壓器型逆變器。

光伏逆變器作為整個電站的檢測中心，上對直流組件，下對并網(wǎng)設(shè)備，基本所有的電站參數(shù)都可以通過逆變器檢測出來。一般逆變器只要在并網(wǎng)狀態(tài)，監(jiān)控顯示的功率曲線為正常的“山”行，證明該電站運行穩(wěn)定，如果出現(xiàn)異常，則可以通過逆變器反饋的信息檢查電站配套設(shè)備健康狀況。下面整理了一些光伏逆變器常見的故障原因分析與處理方法：

1、光伏逆變器屏幕沒有顯示

故障分析：沒有直流輸入，逆變器LCD是由直流供電的。

可能原因：

（1）組件電壓不夠。逆變器工作電壓是100V到500V，低于100V時，逆變器不工作。組件電壓和太陽能輻照度有關(guān)。

（2）PV輸入端子接反，PV端子有正負兩極，要互相對應(yīng)，不能和別的組串接反。

（3）直流開關(guān)沒有合上。

（4）組件串聯(lián)時，某一個接頭沒有接好。

（5）有一組件短路，造成其他組串也不能工作。

解決辦法：用完用表電壓檔測量逆變器直流輸入電壓。電壓正常時，總電壓是各組件電壓之和。如果沒有電壓，依次檢測直流開關(guān)，接線端子，電纜接頭，組件等是否正常。如果有多路組件，要分開單獨接入測試。如果逆變器是使用一段時間，沒有發(fā)現(xiàn)原因，則是逆變器硬件電路發(fā)生故障，可以聯(lián)系生產(chǎn)廠家售后。

2、光伏逆變器不并網(wǎng)，屏幕顯示市電未接

故障現(xiàn)象：逆變器不并網(wǎng)，屏幕顯示市電未接

故障分析：逆變器和電網(wǎng)沒有連接

可能原因：

（1）交流開關(guān)沒有合上。

（2）逆變器交流輸出端子沒有接上。

（3）接線時，把逆變器輸出接線端子上排松動了。

解決辦法：用萬用表電壓檔測量逆變器交流輸出電壓，在正常情況下，輸出端子應(yīng)該有220V或者380V電壓，如果沒有，依次檢測接線端子是否有松動，交流開關(guān)是否閉合，漏電保護開關(guān)是否斷開。

3、屏幕顯示PV電壓高

故障分析：直流電壓過高報警

可能原因：組件串聯(lián)數(shù)量過多，造成電壓超過逆變器的電壓。

解決辦法：因為組件的溫度特性，溫度越低，電壓越高。單相組串式逆變器輸入電壓范圍是100-500V，建議組串后電壓在350-400V之間，三相組串式逆變器輸入電壓范圍是250-800V，建議組串后電壓在600-650V之間。在這個電壓區(qū)間，逆變器效率較高，早晚輻照度低時也可發(fā)電，但又不至于電壓超出逆變器電壓上限，引起報警而停機。

4、屏幕顯示PV絕緣阻抗過低

故障分析：光伏系統(tǒng)接地絕緣電阻小于2兆歐

可能原因：太陽能組件，接線盒，直流電纜，逆變器，交流電纜，接線端子等地方有電線對地短路或者絕緣層破壞。PV接線端子和交流接線外殼松動，導(dǎo)致進水。

解決辦法：斷開電網(wǎng)，逆變器，依次檢查各部件電線對地的電阻，找出問題點，并更換。

5、屏幕顯示輸出漏電流過高

故障分析：漏電流太大

解決辦法：取下PV陣列輸入端，然后檢查外圍的AC電網(wǎng)。直流端和交流端全部斷開，讓逆變器停電30分鐘以上，如果自己能恢復(fù)就繼續(xù)使用，如果不能恢復(fù)，聯(lián)系售后技術(shù)工程師。

6、屏幕顯示市電電壓超范圍

故障分析：電網(wǎng)電壓過高。電網(wǎng)阻抗增大，光伏發(fā)電用戶側(cè)消化不了，輸送出去時又因阻抗過大，造成逆變器輸出側(cè)電壓過高，引起逆變器保護關(guān)機，或者降額運行。

解決辦法：

（1）加大輸出電纜，因為電纜越粗，阻抗越低。

（2）逆變器靠近并網(wǎng)點，電纜越短，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.