儲能系統(tǒng)的類型

根據(jù)不同的應用場合，太陽能光伏儲能發(fā)電系統(tǒng)分為離網(wǎng)發(fā)電系統(tǒng)、并離網(wǎng)儲能系統(tǒng)、并網(wǎng)儲能系統(tǒng)和多種能源混合微網(wǎng)系統(tǒng)等四種。

01

光伏離網(wǎng)發(fā)電系統(tǒng)

光伏離網(wǎng)發(fā)電系統(tǒng)，不依賴電網(wǎng)而獨立運行，應用于偏僻山區(qū)、無電區(qū)、海島、通訊基站和路燈等應用場所。系統(tǒng)由光伏方陣、太陽能控制器、逆變器、蓄電池組、負載等構(gòu)成。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給負載供電，同時給蓄電池組充電；在無光照時，由蓄電池通過逆變器給交流負載供電。

圖1、離網(wǎng)發(fā)電系統(tǒng)示意圖

光伏離網(wǎng)發(fā)電系統(tǒng)是專門針對無電網(wǎng)地區(qū)或經(jīng)常停電地區(qū)場所使用的，是剛性需求，離網(wǎng)系統(tǒng)不依賴于電網(wǎng)，靠的是“邊儲邊用”或者“先儲后用”的工作模式，干的是“雪中送炭”的事情。對于無電網(wǎng)地區(qū)或經(jīng)常停電地區(qū)家庭來說，離網(wǎng)系統(tǒng)具有很強的實用性，目前光伏離網(wǎng)度電成本約1.0-1.5元，相比并網(wǎng)系統(tǒng)要高很多，但相比燃油發(fā)電機的度電成本1.5-2.0元，更經(jīng)濟環(huán)保。

02

并離網(wǎng)儲能系統(tǒng)

并離網(wǎng)型光伏發(fā)電系統(tǒng)廣泛應用于經(jīng)常停電，或者光伏自發(fā)自用不能余量上網(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等應用場所。

圖2、并離網(wǎng)發(fā)電系統(tǒng)示意圖

系統(tǒng)由太陽電池組件組成的光伏方陣、太陽能并離網(wǎng)一體機、蓄電池組、負載等構(gòu)成。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給負載供電，同時給蓄電池組充電；在無光照時，由蓄電池給太陽能控制逆變一體機供電，再給交流負載供電。

相對于并網(wǎng)發(fā)電系統(tǒng)，并離網(wǎng)系統(tǒng)增加了充放電控制器和蓄電池，系統(tǒng)成本增加了30%左右，但是應用范圍更寬。一是可以設定在電價峰值時以額定功率輸出，減少電費開支；二是可以電價谷段充電，峰段放電，利用峰谷差價賺錢；三是當電網(wǎng)停電時，光伏系統(tǒng)做為備用電源繼續(xù)工作，逆變器可以切換為離網(wǎng)工作模式，光伏和蓄電池可以通過逆變器給負載供電。

03

光伏并網(wǎng)儲能系統(tǒng)

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)自用比例，應用于光伏自發(fā)自用不能余量上網(wǎng)、自用電價比上網(wǎng)電價價格貴很多、波峰電價比波平電價貴很多等應用場所。系統(tǒng)由太陽電池組件組成的光伏方陣、太陽能控制器、電池組、并網(wǎng)逆變器、電流檢測裝置、負載等構(gòu)成。當太陽能功率小于負載功率時，系統(tǒng)由太陽能和電網(wǎng)一起供電，當太陽能功率大于負載功率時，太陽能一部分給負載供電，一部分通過控制器儲存起來。

圖3、 并網(wǎng)儲能系統(tǒng)示意圖

在一些國家和地區(qū)，之前裝了一套光伏系統(tǒng)，后取消了光伏補貼，就可以安裝一套并網(wǎng)儲能系統(tǒng)，讓光伏發(fā)電完全自發(fā)自用。并網(wǎng)儲能機可以兼容各個廠家的逆變器，原來的系統(tǒng)可以不做任何改動。當電流傳感器檢測到有電流流向電網(wǎng)時，并網(wǎng)儲能機開始工作，把多余的電能儲存到蓄電池中，如果蓄電池也充滿了，還可以打開電熱水器。晚上家庭負載增加時，可以控制蓄電池通過逆變器向負載送電。

04

微網(wǎng)儲能系統(tǒng)

微網(wǎng)系統(tǒng)由太陽能電池方陣、并網(wǎng)逆變器、PCS雙向變流器、智能切換開關(guān)、蓄電池組、發(fā)電機、負載等構(gòu)成。光伏方陣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雙向變流器給負載供電。

微電網(wǎng)可充分有效地發(fā)揮分布式清潔能源潛力，減少容量小、發(fā)電功率不穩(wěn)定、獨立供電可靠性低等不利因素，確保電網(wǎng)安全運行，是大電網(wǎng)的有益補充。微電網(wǎng)可以促進傳統(tǒng)產(chǎn)業(yè)的升級換代，從經(jīng)濟環(huán)保的角度可以發(fā)揮巨大作用。專家表示，微電網(wǎng)應用靈活，規(guī)?？梢詮臄?shù)千瓦直至幾十兆瓦，大到廠礦企業(yè)、醫(yī)院學校，小到一座建筑都可以發(fā)展微電網(wǎng)。

Type of energy storage system  

 

 

 

According to different application occasions, solar photovoltaic energy storage power generation system can be divided into off-grid power generation system, off-grid energy storage system, grid-connected energy storage system and a variety of energy hybrid micro-grid system.  

 

 

 

 

01  

Photovoltaic off-grid power generation system  

 

 

Photovoltaic off-grid power generation system, independent of power grid operation, applied in remote mountainous areas, no power areas, islands, communication base stations and street lights and other application places.   The system consists of photovoltaic array, solar controller, inverter, battery pack, load and so on.   The photovoltaic square array converts solar energy into electricity under the condition of illumination, and supplies power to the load through the solar controlled inverter and charges the battery group at the same time.  In the absence of light, the battery supplies power to the AC load through an inverter.  

 

 

 

The picture  

 

FIG. 1 schematic diagram of off-grid power generation system  

 

 

 

Photovoltaic off-grid power generation system is specially designed for use in areas without power grid or areas with frequent power outages. It is a rigid demand. Off-grid system does not depend on the power grid, relying on the working mode of "storage while using" or "storage before using".   For households in areas without power grid or areas with frequent power outages, the off-grid system has strong practicability. At present, the off-grid electricity cost of photovoltaic is about 1.0-1.5 yuan per kilowatt hour, much higher than that of the grid-connected system, but compared with the oil-fired generator, the electricity cost is 1.5-2.0 yuan per kilowatt hour, which is more economic and environmental friendly.  

 

 

 

02  

And off-grid energy storage system  

 

And off-grid photovoltaic power generation system is widely used in frequent power outage, or photovoltaic spontaneous self-use can not spare the Internet, self-use electricity price is much more expensive than the grid price, the peak price is much more expensive than the trough price and other application places.  

 

 

 

The picture  

 

 

 

FIG. 2 schematic diagram of parallel off-grid power generation system  

 

 

 

The system is composed of photovoltaic array composed of solar cell modules, solar energy and off-grid integrated machine, battery pack, load, etc.   The photovoltaic square array converts solar energy into electricity under the condition of illumination, and supplies power to the load through the solar controlled inverter and charges the battery group at the same time.  When there is no light, the battery supplies power to the solar controlled inverter and then to the AC load.  

 

 

 

Relative to the grid-connected power generation system, and off-grid system increases the charge and discharge controller and battery, the system cost increases by about 30%, but the application range is wider.   First, it can be set at the peak of the electricity price to the rated power output, reduce the cost of electricity;   Second, the price of electricity valley charge, peak discharge, the use of peak valley difference to make money;  Third, when the power grid fails, the photovoltaic system continues to work as a backup power supply, and the inverter can switch to off-grid working mode. Photovoltaic and battery can supply power to the load through the inverter.  

 

 

 

03  

Photovoltaic grid-connected energy storage system  

 

 

Grid-connected energy storage photovoltaic power generation system, can store excess power generation, improve the ratio of spontaneous self-use, applied to photovoltaic spontaneous self-use can not spare the Internet, self-use electricity price is much more expensive than the price of the grid, wave electricity price is much more expensive than wave flat electricity price and other applications.   The system is composed of photovoltaic array, solar controller, battery pack, grid-connected inverter, current detection device, load and so on.  When the solar power is less than the load power, the system is powered by solar energy and the grid together. When the solar power is greater than the load power, part of the solar energy supplies power to the load, and part of the controller is stored.  

 

The picture  

 

FIG. 3 Schematic diagram of grid-connected energy storage system  

 

 

 

In some countries and regions, a set of photovoltaic system installed before the removal of photovoltaic subsidies, can be installed a set of grid-connected energy storage system, photovoltaic power generation is completely self-sustaining.   Grid-connected energy storage machine can be compatible with the inverter of various manufacturers, the original system can not do any change.  When the current sensor detects a flow of electricity to the grid, the grid-connected accumulator kicks in, storing excess energy into a battery, and turning on the electric water heater if the battery is also full.  When the home load increases at night, the battery can be controlled through the inverter to send electricity to the load.  

 

 

 

04  

Microgrid energy storage system  

 

 

The microgrid system consists of solar cell array, grid-connected inverter, PCS two-way converter, intelligent switch, battery pack, generator, load, etc.   Photovoltaic array converts solar energy into electric energy under the condition of illumination, supplies power to the load through the inverter, and charges the battery pack through PCS two-way converter.   In the absence of light, the battery supplies power to the load through PCS two-way converters.  

 

 

 

Microgrid can give full and effective play to the potential of distributed clean energy, reduce adverse factors such as small capacity, unstable power generation and low reliability of independent power supply, ensure the safe operation of power grid, and is a beneficial supplement to large power grid.   Microgrid can promote the upgrading of traditional industries and play a huge role from the perspective of economic and environmental protection.  Experts say that the application of microgrid is flexible, and the scale can range from several kilowatts to dozens of megawatts. It can be developed in factories, mines, hospitals, schools and even a building.