太阳能光伏发电形式

并网和离网的说法，作为专业人员来说稍显粗糙。在实践应用中，根据不同的应用场合，太阳能光伏发电系统一般分为并网光伏发电系统、离网光伏发电系统、并离网光伏发电系统、并网储能光伏发电系统和多能互补智慧能源系统五种。目前，交大光谷太阳能工程技术研究中心主要对并离网光伏发电系统、并网储能光伏发电系统和多能互补智慧能源系统进行研究和系统优化。下面，我们针对这5种太阳能光伏发电系统形式逐一分析。

1、并网光伏发电系统

并网光伏发电系统的应用场景，公共电力供应正常，并网方便，光伏发的电可出售给公共电网。并网光伏发电系统主要有两种上网模式，一个是“自发自用、余电上网”，另一个是“全额上网”。一般分布式光伏发电系统主要采用“自发自用、余电上网”模式，太阳能电池产生的电优先给负载，当负载用不完后，多余的电送入电网，当供给负载电量不够时，电网和光伏系统可以同时给负载供电。光伏并网系统由组件、并网逆变器、光伏电表、负载、双向电表、并网柜和电网组成，光伏组件由光照产生直流电经过逆变器转换成交流电供给负载和送入电网。

2、离网光伏发电系统

离网光伏发电系统的应用场景为偏僻山区、无电区、海岛、通讯基站和路灯等，目前，交大光谷太阳能国际贸易部销售到非洲、东南亚、中东、拉丁美洲等欠发达国家的光伏发电系统主要为离网光伏发电系统。离网发电系统在有光照的情况下将太阳能转换为电能，通过太阳能控制逆变一体机给负载供电，同时给蓄电池充电；在无光照时，由蓄电池通过逆变器给交流负载供电。系统一般由光伏组件、太阳能控制器、逆变器、蓄电池、负载等构成。

3、并离网光伏发电系统

并离网光伏发电系统的应用场景为经常停电，或者光伏自发自用不能余电上网、自用电价比上网电价贵很多、波峰电价比波谷电价贵很多的场所。该系统的好处是可获得政府补贴，在公共电力断电时系统可以独立发电供电。并离网光伏发电系统的工作原理为光伏方阵在有光照的情况下将太阳能转换为电能，通过太阳能控制逆变一体机给负载供电，同时给蓄电池充电；在无光照时，由蓄电池给太阳能控制逆变一体机供电，再给交流负载供电。该系统相比并网发电系统，增加了充放电控制器和蓄电池，在电网停电时，光伏系统还可以继续工作，逆变器可以切换成离网工作模式，给负载供电。系统由光伏组件、太阳能并离网一体机、蓄电池、负载等构成。

4、并网储能光伏发电系统

并网储能光伏发电系统的应用场景，光储充电站、工业园区、数据中心、通信基站、变电站、火电厂、风电场、热电厂、地铁、有轨电车、港口岸、医院、银行、商场、酒店、政务楼宇、军区营地、社区健身场馆、田园生态园区、大型活动晚会现场、足球俱乐部、动物园、流动警务室、流动哨所、石油井、岛屿等。

光储充一体化，目前是比较普遍的应用场景，一方面缓解了充电高峰时充电桩大电流充电对区域电网的冲击，另一方面通过峰谷差价，给充电站带来了非常可观的收益。

并网储能光伏发电系统，能够存储多余的发电量，提高自发自用的比例。

系统由光伏组件、太阳能控制器、蓄电池、并网储能逆变器、电流检测装置、负载等构成。当太阳能功率小于负载功率时，系统由太阳能和电网一起供电，当太阳能功率大于负载功率时，太阳能一部分给负载供电，一部分通过控制器将用不完的电储存起来。

5、多能互补智慧能源系统

多能互补智慧能源系统为智慧城市、智慧社区、智慧园区等适用微电网的应用场景提供优质高效的清洁电力。微电网（Micro-Grid），是一种新型网结构，由分布式电源、负荷、储能系统和控制装置构成的配电网络。可将分散能源就地转换为电能，然后就近供给本地负载。微电网是一个能够实现自我控制、保护和管理的自治系统，既可以与外部电网并网运行，也可以孤立运行。

微电网是将多种类型的分布式电源有效组合在一起，实现多种能源互补，提高能源利用率。能够充分促进分布式电源与可再生能源的大规模接入，实现对负荷多种能源形式的高可靠供给，是实现主动式配电网的一种有效方式，是传统电网向智能电网过渡。

微网系统由光伏组件、并网逆变器、PCS双向变流器、智能切换开关、蓄电池、发电机、负载等构成。光伏组件在有光照的情况下将太阳能转换为电能，通过逆变器给负载供电，同时通过PCS双向变流器给蓄电池组充电；在无光照时，由蓄电池通过PCS双向变流器向负载供电。

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.