并網(wǎng)和離網(wǎng)的說法，作為專業(yè)人員來說稍顯粗糙。在實踐應(yīng)用中，根據(jù)不同的應(yīng)用場合，太陽能光伏發(fā)電系統(tǒng)一般分為并網(wǎng)光伏發(fā)電系統(tǒng)、離網(wǎng)光伏發(fā)電系統(tǒng)、并離網(wǎng)光伏發(fā)電系統(tǒng)、并網(wǎng)儲能光伏發(fā)電系統(tǒng)和多能互補(bǔ)智慧能源系統(tǒng)五種。目前，交大光谷太陽能工程技術(shù)研究中心主要對并離網(wǎng)光伏發(fā)電系統(tǒng)、并網(wǎng)儲能光伏發(fā)電系統(tǒng)和多能互補(bǔ)智慧能源系統(tǒng)進(jìn)行研究和系統(tǒng)優(yōu)化。下面，我們針對這5種太陽能光伏發(fā)電系統(tǒng)形式逐一分析。

1、并網(wǎng)光伏發(fā)電系統(tǒng)

并網(wǎng)光伏發(fā)電系統(tǒng)的應(yīng)用場景，公共電力供應(yīng)正常，并網(wǎng)方便，光伏發(fā)的電可出售給公共電網(wǎng)。并網(wǎng)光伏發(fā)電系統(tǒng)主要有兩種上網(wǎng)模式，一個是“自發(fā)自用、余電上網(wǎng)”，另一個是“全額上網(wǎng)”。一般分布式光伏發(fā)電系統(tǒng)主要采用“自發(fā)自用、余電上網(wǎng)”模式，太陽能電池產(chǎn)生的電優(yōu)先給負(fù)載，當(dāng)負(fù)載用不完后，多余的電送入電網(wǎng)，當(dāng)供給負(fù)載電量不夠時，電網(wǎng)和光伏系統(tǒng)可以同時給負(fù)載供電。光伏并網(wǎng)系統(tǒng)由組件、并網(wǎng)逆變器、光伏電表、負(fù)載、雙向電表、并網(wǎng)柜和電網(wǎng)組成，光伏組件由光照產(chǎn)生直流電經(jīng)過逆變器轉(zhuǎn)換成交流電供給負(fù)載和送入電網(wǎng)。

2、離網(wǎng)光伏發(fā)電系統(tǒng)

離網(wǎng)光伏發(fā)電系統(tǒng)的應(yīng)用場景為偏僻山區(qū)、無電區(qū)、海島、通訊基站和路燈等，目前，交大光谷太陽能國際貿(mào)易部銷售到非洲、東南亞、中東、拉丁美洲等欠發(fā)達(dá)國家的光伏發(fā)電系統(tǒng)主要為離網(wǎng)光伏發(fā)電系統(tǒng)。離網(wǎng)發(fā)電系統(tǒng)在有光照的情況下將太陽能轉(zhuǎn)換為電能，通過太陽能控制逆變一體機(jī)給負(fù)載供電，同時給蓄電池充電；在無光照時，由蓄電池通過逆變器給交流負(fù)載供電。系統(tǒng)一般由光伏組件、太陽能控制器、逆變器、蓄電池、負(fù)載等構(gòu)成。

3、并離網(wǎng)光伏發(fā)電系統(tǒng)

并離網(wǎng)光伏發(fā)電系統(tǒng)的應(yīng)用場景為經(jīng)常停電，或者光伏自發(fā)自用不能余電上網(wǎng)、自用電價比上網(wǎng)電價貴很多、波峰電價比波谷電價貴很多的場所。該系統(tǒng)的好處是可獲得政府補(bǔ)貼，在公共電力斷電時系統(tǒng)可以獨立發(fā)電供電。并離網(wǎng)光伏發(fā)電系統(tǒng)的工作原理為光伏方陣在有光照的情況下將太陽能轉(zhuǎn)換為電能，通過太陽能控制逆變一體機(jī)給負(fù)載供電，同時給蓄電池充電；在無光照時，由蓄電池給太陽能控制逆變一體機(jī)供電，再給交流負(fù)載供電。該系統(tǒng)相比并網(wǎng)發(fā)電系統(tǒng)，增加了充放電控制器和蓄電池，在電網(wǎng)停電時，光伏系統(tǒng)還可以繼續(xù)工作，逆變器可以切換成離網(wǎng)工作模式，給負(fù)載供電。系統(tǒng)由光伏組件、太陽能并離網(wǎng)一體機(jī)、蓄電池、負(fù)載等構(gòu)成。

4、并網(wǎng)儲能光伏發(fā)電系統(tǒng)

并網(wǎng)儲能光伏發(fā)電系統(tǒng)的應(yīng)用場景，光儲充電站、工業(yè)園區(qū)、數(shù)據(jù)中心、通信基站、變電站、火電廠、風(fēng)電場、熱電廠、地鐵、有軌電車、港口岸、醫(yī)院、銀行、商場、酒店、政務(wù)樓宇、軍區(qū)營地、社區(qū)健身場館、田園生態(tài)園區(qū)、大型活動晚會現(xiàn)場、足球俱樂部、動物園、流動警務(wù)室、流動哨所、石油井、島嶼等。

光儲充一體化，目前是比較普遍的應(yīng)用場景，一方面緩解了充電高峰時充電樁大電流充電對區(qū)域電網(wǎng)的沖擊，另一方面通過峰谷差價，給充電站帶來了非?？捎^的收益。

并網(wǎng)儲能光伏發(fā)電系統(tǒng)，能夠存儲多余的發(fā)電量，提高自發(fā)自用的比例。

系統(tǒng)由光伏組件、太陽能控制器、蓄電池、并網(wǎng)儲能逆變器、電流檢測裝置、負(fù)載等構(gòu)成。當(dāng)太陽能功率小于負(fù)載功率時，系統(tǒng)由太陽能和電網(wǎng)一起供電，當(dāng)太陽能功率大于負(fù)載功率時，太陽能一部分給負(fù)載供電，一部分通過控制器將用不完的電儲存起來。

5、多能互補(bǔ)智慧能源系統(tǒng)

多能互補(bǔ)智慧能源系統(tǒng)為智慧城市、智慧社區(qū)、智慧園區(qū)等適用微電網(wǎng)的應(yīng)用場景提供優(yōu)質(zhì)高效的清潔電力。微電網(wǎng)（Micro-Grid），是一種新型網(wǎng)結(jié)構(gòu)，由分布式電源、負(fù)荷、儲能系統(tǒng)和控制裝置構(gòu)成的配電網(wǎng)絡(luò)?？蓪⒎稚⒛茉淳偷剞D(zhuǎn)換為電能，然后就近供給本地負(fù)載。微電網(wǎng)是一個能夠?qū)崿F(xiàn)自我控制、保護(hù)和管理的自治系統(tǒng)，既可以與外部電網(wǎng)并網(wǎng)運行，也可以孤立運行。

微電網(wǎng)是將多種類型的分布式電源有效組合在一起，實現(xiàn)多種能源互補(bǔ)，提高能源利用率。能夠充分促進(jìn)分布式電源與可再生能源的大規(guī)模接入，實現(xiàn)對負(fù)荷多種能源形式的高可靠供給，是實現(xiàn)主動式配電網(wǎng)的一種有效方式，是傳統(tǒng)電網(wǎng)向智能電網(wǎng)過渡。

微網(wǎng)系統(tǒng)由光伏組件、并網(wǎng)逆變器、PCS雙向變流器、智能切換開關(guān)、蓄電池、發(fā)電機(jī)、負(fù)載等構(gòu)成。光伏組件在有光照的情況下將太陽能轉(zhuǎn)換為電能，通過逆變器給負(fù)載供電，同時通過PCS雙向變流器給蓄電池組充電；在無光照時，由蓄電池通過PCS雙向變流器向負(fù)載供電。

The terms of grid-connected and off-grid are somewhat crude for professionals.  In practical application, according to different application occasions, solar photovoltaic power generation system is generally divided into grid-connected photovoltaic power generation system, off-grid photovoltaic power generation system, off-grid photovoltaic power generation system, grid-connected energy storage photovoltaic power generation system and multi-energy complementary smart energy system. At present, the Solar Energy Engineering and Technology Research Center of Optical Valley of Jiaotong University mainly researches and optimizes parallel off-grid photovoltaic power generation system, grid-connected energy storage photovoltaic power generation system and multi-energy complementary smart energy system.   In the following, we analyze the five solar photovoltaic power generation systems one by one.  

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1. Grid-connected photovoltaic power generation system  

In the application scenario of grid-connected photovoltaic power generation system, the public power supply is normal and the grid connection is convenient. The electricity generated by photovoltaic can be sold to the public grid.   There are two main Internet access modes for grid-connected photovoltaic power generation system, one is "self-use, surplus electricity online", and the other is "full Internet access".   Generally, the distributed photovoltaic power generation system mainly adopts the mode of "self-use and surplus electricity online". The electricity generated by solar cells is given priority to the load. When the load is not used up, the excess electricity is sent to the grid.  The photovoltaic grid-connected system is composed of modules, grid-connected inverter, photovoltaic meter, load, two-way meter, grid-connected cabinet and power grid. The photovoltaic module generates direct current by illumination and converts it into alternating current through the inverter to supply load and send to the power grid.  

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2. Off-grid photovoltaic power generation system  

The application scenarios of off-grid photovoltaic power generation systems are remote mountainous areas, areas without electricity, islands, communication base stations and street lamps, etc. At present, the photovoltaic power generation systems sold by the Solar Energy International Trade Department of Optical Valley of Jiaotong University to underdeveloped countries such as Africa, Southeast Asia, the Middle East and Latin America are mainly off-grid photovoltaic power generation systems.   The off-grid power generation system converts the solar energy into electric energy under the condition of light, and uses the solar energy to control the inverter to power the load and charge the battery at the same time.  In the absence of light, the battery supplies power to the AC load through the inverter.   The system is generally composed of photovoltaic module, solar controller, inverter, battery, load and so on.  

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3, and off-grid photovoltaic power generation system  

And off-grid photovoltaic power generation system application scenarios for frequent power outages, or photovoltaic spontaneous self-use cannot surplus electricity online, self-use electricity price is much more expensive than the on-grid electricity price, wave peak electricity price is much more expensive than the trough electricity price.   The benefit of the system is that it is subsidized by the government and can generate electricity independently when the public power is off.  The working principle of the off-grid photovoltaic power generation system is that the photovoltaic array converts solar energy into electric energy under the condition of illumination, and the inverter is controlled by solar energy to power the load and charge the battery at the same time.  When there is no light, the battery supplies power to the solar controlled inverter and then to the AC load.  Compared with grid-connected power generation system, this system adds charge and discharge controller and battery. When the power grid is cut off, the photovoltaic system can continue to work, and the inverter can be switched to off-grid mode to supply power to the load.  The system consists of photovoltaic module, solar energy and off-grid integrated machine, battery, load and so on.  

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4. Grid-connected energy storage photovoltaic power generation system  

Application scenarios of grid-connected energy storage photovoltaic power generation system,  Optical storage stations, industrial park, data center, communication base station, substation, power plants, wind power, thermal power plant, subway, tram, harbor, hospitals, Banks, shopping malls, hotels, government buildings, military camps, community fitness venues, rural ecological park, large-scale activities of the party scene, football club, the zoo, flow chamber, flow of police stations, oil Wells, island  Lantau, etc.  

The integration of optical storage and charging is a common application scenario at present. On the one hand, it alleviates the impact of high-current charging of charging pile on regional power grid during peak charging period, and on the other hand, it brings considerable profits to charging stations through peak-valley price difference.  

Grid-connected energy storage photovoltaic power generation system can store excess power generation and improve the proportion of self-use.  

The system consists of photovoltaic module, solar controller, battery, grid-connected energy storage inverter, current detection device, load and so on.  When the solar power is less than the load power, the system is powered by the solar power and the grid together. When the solar power is greater than the load power, part of the solar power supplies the load and part of the power is stored by the controller.  

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5. Multiple complementary smart energy systems  

Multi-energy complementary smart energy systems provide high-quality and efficient clean power for smart cities, smart communities, smart parks and other application scenarios applicable to microgrids.   Micro-grid is a new type of network structure, which is composed of distributed power supply, load, energy storage system and control device.  The decentralized energy can be converted into electricity locally and then supplied to local loads nearby.  Microgrid is an autonomous system capable of self-control, protection and management, which can be connected to the external grid or operate in isolation.  

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Microgrid is an effective combination of various types of distributed power sources to achieve a variety of energy complementarity and improve energy utilization.   It can fully promote the large-scale access of distributed power supply and renewable energy, and realize the highly reliable supply of multiple energy forms of load. It is an effective way to realize the active distribution network and the transition from traditional power grid to smart grid.  

The microgrid system is composed of photovoltaic modules, grid-connected inverters, PCS two-way converters, intelligent switching switches, batteries, generators, loads, etc.   The photovoltaic module converts the solar energy into electric energy under the condition of illumination, supplies power to the load through the inverter, and charges the battery bank through the PCS two-way converter.  In the absence of light, the battery supplies power to the load through PCS bidirectional converters.