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 Comparison of monocrystalline, polycrystalline and non-silicon bushel-film large solar cells

 Table 5.1.1-6
 Battery type  crystallographic  film type
 single crystal silicon  polycrystalline silicon (used in electronics)  amorphous silicon  Cadmium telluride  copper indium gallium selenide (CIGS)
 Commercial efficiency 22.5 % ∼ 24.9 % 22.5 % ∼ 24.9 % 22.5%∼24.9%22.5 \% \sim 24.9 \% 19.0 % ∼ 22.1 % 19.0 % ∼ 22.1 % 19.0%∼22.1%19.0 \% \sim 22.1 \% 6 % ∼ 8 % 6 % ∼ 8 % 6%∼8%6 \% \sim 8 \% 8.5 % ∼ 10.5 % 8.5 % ∼ 10.5 % 8.5%∼10.5%8.5 \% \sim 10.5 \% 10 % ∼ 12 % 10 % ∼ 12 % 10%∼12%10 \% \sim 12 \%
 Laboratory efficiency 26.1 % 26.1 % 26.1%26.1 \% 23.3 % 23.3 % 23.3%23.3 \% 14.0 % 14.0 % 14.0%14.0 \% 22.1 % 22.1 % 22.1%22.1 \% 23.3 % 23.3 % 23.3%23.3 \%
 service life  25 years  25 years  25 years  25 years  20 years
 Component Layer Thickness  thick layer  thick layer  lamina  thin slice  thin slice
 large-scale production  already formed  already formed  already formed  already formed  proven
 Environmental issues  turbanness  unisex  unisex  Yes (with cadmium)  Neutral except for cadmium
 Energy reimbursement   2 ∼ 3 2 ∼ 3 2∼32 \sim 3 Year   2 ∼ 3 2 ∼ 3 2∼32 \sim 3 Year   1 ∼ 2 1 ∼ 2 1∼21 \sim 2 Year   1 ∼ 2 1 ∼ 2 1∼21 \sim 2 Year   1 ∼ 2 1 ∼ 2 1∼21 \sim 2 Year
 production costs  high  high  relatively low  relatively low  relatively low
 Key Benefits
 High efficiency and mature technology
效率高 技术成熟| 效率高 | | :---: | | 技术成熟 |
 High efficiency and mature technology
效率高 技术成熟| 效率高 | | :---: | | 技术成熟 |
 Good low light effect Lower cost
弱光效应好 成本较低| 弱光效应好 | | :---: | | 成本较低 |
 Good low light effect Relatively low cost
弱光效应好 成本相对较低| 弱光效应好 | | :---: | | 成本相对较低 |
 Good low light effect Relatively low cost
弱光效应好 成本相对较低| 弱光效应好 | | :---: | | 成本相对较低 |
电池种类 晶体类 薄膜类 单晶硅 多晶硅 非晶硅 碲化镉 铜铟镓硒 商用效率 22.5%∼24.9% 19.0%∼22.1% 6%∼8% 8.5%∼10.5% 10%∼12% 实验室效率 26.1% 23.3% 14.0% 22.1% 23.3% 使用寿命 25 年 25 年 25 年 25 年 20 年 组件层厚度 厚层 厚层 薄层 薄层 薄层 规模生产 已形成 已形成 已形成 已形成 已证明可行 环境问题 巾性 中性 中性 有 (使用镉) 除镉外为中性 能量偿还时 2∼3 年 2∼3 年 1∼2 年 1∼2 年 1∼2 年 生产成本 较高 较高 较低 相对较低 相对较低 主要优点 "效率高 技术成熟" "效率高 技术成熟" "弱光效应好 成本较低" "弱光效应好 成本相对较低" "弱光效应好 成本相对较低"| 电池种类 | 晶体类 | | 薄膜类 | | | | :---: | :---: | :---: | :---: | :---: | :---: | | | 单晶硅 | 多晶硅 | 非晶硅 | 碲化镉 | 铜铟镓硒 | | 商用效率 | $22.5 \% \sim 24.9 \%$ | $19.0 \% \sim 22.1 \%$ | $6 \% \sim 8 \%$ | $8.5 \% \sim 10.5 \%$ | $10 \% \sim 12 \%$ | | 实验室效率 | $26.1 \%$ | $23.3 \%$ | $14.0 \%$ | $22.1 \%$ | $23.3 \%$ | | 使用寿命 | 25 年 | 25 年 | 25 年 | 25 年 | 20 年 | | 组件层厚度 | 厚层 | 厚层 | 薄层 | 薄层 | 薄层 | | 规模生产 | 已形成 | 已形成 | 已形成 | 已形成 | 已证明可行 | | 环境问题 | 巾性 | 中性 | 中性 | 有 (使用镉) | 除镉外为中性 | | 能量偿还时 | $2 \sim 3$ 年 | $2 \sim 3$ 年 | $1 \sim 2$ 年 | $1 \sim 2$ 年 | $1 \sim 2$ 年 | | 生产成本 | 较高 | 较高 | 较低 | 相对较低 | 相对较低 | | 主要优点 | 效率高 <br> 技术成熟 | 效率高 <br> 技术成熟 | 弱光效应好 <br> 成本较低 | 弱光效应好 <br> 成本相对较低 | 弱光效应好 <br> 成本相对较低 |

According to the following chart can be analyzed to get, 2020 monocrystalline silicon photovoltaic module market share has been significantly ahead of polycrystalline silicon modules, is expected in 2027 the global monocrystalline silicon market share will exceed 90 % 90 % 90%90 \% . Photovoltaic power station solar cell types should choose mature technology, high conversion efficiency, has been the scale of production and in the domestic engineering application examples of components as the core device of photovoltaic conversion. Therefore, taking into account the monocrystalline cell efficiency is higher, the large capacity of the component to bring lower cost of electricity, the mainstream models of components on the market, so the project selects monocrystalline modules.

Figure 5.1.1-10 Solar Panel Type Market Share Trends

Considering that the components have not yet been procured, the nominal power of N-type modules is 585 Wp - 700 Wp, and researching the relevant manufacturers, Guangjia said that the power of N-type modules is relatively fast, and the N-type modules of this power class have almost no impact on the key design of the photovoltaic power generation system, and that in order to satisfy the supply capacity of the component manufacturers in this year's procurement of the project, the project is temporarily designed according to 615 Wp. In order to meet the supply capacity of module manufacturers in this year's procurement, the 615 Wp module is tentatively designed at this stage, and the N-type monocrystalline silicon Topcon 615 Wp double-glass bifacial module is recommended for program design in this project. The project recommends using N-type monocrystalline silicon Topcon 615 Wp double-glass bifacial modules for the schematic design. Optimization and adjustment will be carried out after the final bidding to determine the specifications of the modules, and the specific models will be subject to the results of the Group's frame bidding, and the main technical parameters are as follows

N-type 615 Wp monocrystalline silicon bifacial double-glazed module main technical parameters
 Table 5.1.1-8
 sports event  parameters
 standard power 615 Wp
 Peak Voltage Vmp 41.1 V
 Peak Current Imp 14.98 A
 Short-circuit current Isc 15.89 A
 Open Circuit Voltage Voc 49.3 V
 Maximum system voltage 1500 V
 Component efficiency 22.8
项目 参数 标准功率 615 Wp 峰值电压 Vmp 41.1 V 峰值电流 Imp 14.98 A 短路电流 Isc 15.89 A 开路电压 Voc 49.3 V 最大系统电压 1500 V 组件效率 22.8| 项目 | 参数 | | :---: | :---: | | 标准功率 | 615 Wp | | 峰值电压 Vmp | 41.1 V | | 峰值电流 Imp | 14.98 A | | 短路电流 Isc | 15.89 A | | 开路电压 Voc | 49.3 V | | 最大系统电压 | 1500 V | | 组件效率 | 22.8 |
 Component Size 2382 × 1134 × 30 mm 2382 × 1134 × 30 mm 2382 xx1134 xx30mm2382 \times 1134 \times 30 \mathrm{~mm}
 Peak Power Temperature Coefficient Tk ( W ) Tk ( W ) Tk(W)\mathrm{Tk}(\mathrm{W}) − 0.29 % / ∘ C − 0.29 % / ∘ C -0.29%//^(@)C-0.29 \% /{ }^{\circ} \mathrm{C}
 Voltage temperature coefficient Tk − 0.24 % / ∘ C − 0.24 % / ∘ C -0.24%//^(@)C-0.24 \% /{ }^{\circ} \mathrm{C}
 Current temperature coefficient Tk ( Isc Tk ( Isc Tk(Isc\mathrm{Tk}(\mathrm{Isc} ) 0.04 / ∘ C 0.04 / ∘ C 0.04//^(@)C0.04 /{ }^{\circ} \mathrm{C}
 operating temperature − 40 − + 85 ∘ C − 40 − + 85 ∘ C -40-+85^(@)C-40-+85{ }^{\circ} \mathrm{C}
 net weight 33.7 kg
组件尺寸 2382 xx1134 xx30mm 峰值功率温度系数 Tk(W) -0.29%//^(@)C 电压温度系数 Tk -0.24%//^(@)C 电流温度系数 Tk(Isc ) 0.04//^(@)C 工作温度 -40-+85^(@)C 净重 33.7 kg| 组件尺寸 | $2382 \times 1134 \times 30 \mathrm{~mm}$ | | :---: | :---: | | 峰值功率温度系数 $\mathrm{Tk}(\mathrm{W})$ | $-0.29 \% /{ }^{\circ} \mathrm{C}$ | | 电压温度系数 Tk | $-0.24 \% /{ }^{\circ} \mathrm{C}$ | | 电流温度系数 $\mathrm{Tk}(\mathrm{Isc}$ ) | $0.04 /{ }^{\circ} \mathrm{C}$ | | 工作温度 | $-40-+85{ }^{\circ} \mathrm{C}$ | | 净重 | 33.7 kg |

Note: The above parameters were tested under light intensity 1000 W / m 2 1000 W / m 2 1000W//m^(2)1000 \mathrm{~W} / \mathrm{m}^{2} , cell temperature 25 ∘ C 25 ∘ C 25^(@)C25^{\circ} \mathrm{C} , and atmospheric quality of 1.5.

 1.1.1 Inverter selection

 1.1.1.1 Main technical principles of PV grid-connected inverter selection


PV grid-connected inverter is a device that converts solar DC to AC, and it is the key equipment of PV power generation system, and its core role is to track the maximum output power of PV array, and connect its energy to the power grid with minimum transformation loss and optimal power quality. The main technical principles of inverter selection are as follows.
 1) Reliable performance and high efficiency.

The current cost of PV power generation system is high, if the inverter itself consumes too much energy during the power generation process, it will inevitably lead to the loss of total power generation and system economy, so the inverter is required to be reliable, efficient, and able to output the maximum power according to the current operating condition of PV modules. Inverter efficiency includes maximum efficiency, European efficiency and Chinese efficiency. China efficiency (according to China's climatic conditions, according to the resources are divided into four categories, in different power point efficiency according to the weighted formula) can better reflect the inverter in different input power comprehensive efficiency characteristics, so the inverter efficiency of this project adopts China efficiency calculation.
 (2) Requires a wide adaptation range of DC input voltage.

Since the terminal voltage of the PV module varies with the load and sunlight intensity, this requires that the inverter power supply must ensure normal operation over a wide range of DC input voltage and stable AC output voltage.
 (3) It has a perfect protection function.

Grid-connected inverter should also have AC over-voltage and under-voltage protection, over-frequency and under-frequency protection, high-temperature protection, AC and DC over-current protection, DC over-voltage protection, anti-islanding protection and other protection functions.
 4) Small waveform distortion and high power factor.

When large-scale photovoltaic power generation systems are operated grid-connected, in order to avoid power pollution of the public power grid, it is required that inverter

The power supply outputs sinusoidal waveforms, the current waveform must be consistent with the external grid, the waveform distortion is less than 5 % 5 % 5%5 \% , the high harmonic content is less than 3 % 3 % 3%3 \% , and the power factor is close to one.
 5) Monitoring and data collection.

The inverter should have a variety of communication interfaces for data acquisition and sent to the central control room, and its controller should also have analog input ports connected to external sensors to measure data such as sunshine and temperature, to facilitate the entire power plant data processing and analysis.

 1.1.1.2 Main forms of grid-connected inverters


Grid-connected inverter DC products are centralized inverters, string inverters, and hub-and-spoke inverters.
 1) Centralized inverter

The centralized inverter is to transform the DC power generated by PV modules into AC power for boosting and grid connection. Therefore, the power of inverter is relatively large, and the power of single inverter is generally 500 kW 、 630 kW 500 kW 、 630 kW 500kW、630kW500 \mathrm{~kW} 、 630 \mathrm{~kW}、 and 1000 kW 、 1250 kW 、 3125 kW 1000 kW 、 1250 kW 、 3125 kW 1000kW、1250kW、3125kW1000 \mathrm{~kW} 、 1250 \mathrm{~kW} 、 3125 \mathrm{~kW}、、 . The megawatt-level box-type inverter station is formed by one or several high-power inverters, and can be integrated with a medium-voltage step-up transformer according to the demand. The centralized inverter solution is shown in the figure below:
 Figure 5.1.2-1 Centralized Inverter Technical Solution
 2) String Inverter

String inverters are used to transform the DC power generated by the PV modules directly into AC power aggregation and then boost and connect to the grid. Therefore, the power of the inverter are relatively small. String inverters are generally used in large-scale grid-connected PV power plants 20 kW ∼ 300 kW 20 kW ∼ 300 kW 20kW∼300kW20 \mathrm{~kW} \sim 300 \mathrm{~kW} .
 Figure 5.1.2-2 String Inverter Technical Solution
 3) Collective inverter

Distributed inverters are characterized by "centralized inverting" and "decentralized MPPT tracking". In the usual technical scheme, each 500 kW inverter only corresponds to 1 ∼ 3 1 ∼ 3 1∼31 \sim 3 road MPPT optimization unit, therefore, if the components with different characteristics, such as dust blockage, shadow blockage, and component degradation, are directly connected in parallel, it is impossible to guarantee the maximum output of each component, and there is a very obvious component matching loss. By adopting MPPT smart converter box, each smart converter box usually has multiple MPPTs to solve the component matching loss caused by the small number of MPPTs in the conventional centralized inverter scheme.
 Figure 5.1.2-3 Distributed Inverter Technical Solution

Combined with the specific characteristics of this project and the inverter technology route market research and other factors, further technical and economic analysis of the inverter selection. The results of the analysis are shown in Tables 5.1-3, 5.1-4.

 Comparison table of three inverter technologies

 Table 5.1.2-1
 programmatic  Centralized solutions  String Smart PV Solutions  Decentralized solutions
 Terrain adaptation  2 to 4-way MPPT, less adaptable to terrain
Multiple MPPT, suitable for mountainous and complex terrain, power generation increased by more than 3%.
Multiple MPPT, suitable for mountainous and complex terrain, power generation increased by more than 2%.
 devise  Design standardization and programme maturity  Need to design for different squares, difficult to design  Design standardization and programme maturity
 bear the weight (of the upper storeys of a building)  Complicated to install and requires specialized heavy equipment

Lightweight, easy to install, can be fixed directly to the PV mounting, no need for a separate foundation
重量较轻, 易于安装, 可直接固定于光伏支架上，无需独立 基础| 重量较轻, 易于安装, 可直接固定于光伏支架上，无需独立 | | :--- | | 基础 |
  Complicated to install and requires specialized heavy equipment
 newsletter  Uses fiber optic transmission, requires excavation and burial
 Wireless or fiber-optic communication solutions are available.
可采用无线通信方案也可采 用光纤传输方案| 可采用无线通信方案也可采 | | :--- | | 用光纤传输方案 |
 Fiber optic transmission, excavation and burial required
采用光纤传输，需要进行开挖埋 设| 采用光纤传输，需要进行开挖埋 | | :--- | | 设 |
 surety  Long DC path, high chance of arc pulling, easy to start a fire  Shorter DC paths for greater safety  Long DC path, high chance of arc pulling, easy to start a fire
 operation and maintenance (O&M)
Fuses, fans need regular maintenance, workload, inverter bad repair, replacement cycle is long		  No fuses, external fan, no inspection, simple equipment replacement
Fuses, fans need regular maintenance, workload, inverter bad repair, replacement cycle is long
 Environment Protection
环境 保护| 环境 | | :--- | | 保护 |
 Cement foundations are not conducive to environmental restoration and cause permanent damage
水泥基础不利于环境恢复，造成 永久性破坏| 水泥基础不利于环境恢复，造成 | | :--- | | 永久性破坏 |
  No inverter room
 Cement foundations are not conducive to environmental restoration and cause permanent damage
水泥基础不利于环境恢复，造成 永久性破坏| 水泥基础不利于环境恢复，造成 | | :--- | | 永久性破坏 |
 Intelligent Management
智能 管理| 智能 | | :--- | | 管理 |
Lack of centralized management platform, high skill level requirements for operation and maintenance personnel, inability to remotely coordinate

Intelligent O&M, Intelligent Detection, Reduced O&M Labor Costs 50 % 50 % 50%50 \%
智能运维、智能检测、降低运 维人力成本 50%| 智能运维、智能检测、降低运 | | :--- | | 维人力成本 $50 \%$ |
Lack of centralized management platform, high skill level of operation and maintenance personnel, no remote coordination.
方案 集中式方案 组串式智能光伏解决方案 集散式方案 地形适应 2～4路 MPPT，对地形适应性较差 多路 MPPT，适合山地复杂地形，发电量提升 3%以上 多路 MPPT，适合山地复杂地形，发电量提升 2%以上 设计 设计标准化，方案成熟 需针对不同方阵进行设计，设计难度较大 设计标准化，方案成熟 承重 安装较复杂，需要专业重型设备 "重量较轻, 易于安装, 可直接固定于光伏支架上，无需独立 基础" 安装较复杂，需要专业重型设备 通讯 采用光纤传输，需要进行开挖埋设 "可采用无线通信方案也可采 用光纤传输方案" "采用光纤传输，需要进行开挖埋 设" 安全 直流路径长，拉弧机率大，易起火灾 直流路径短，更安全 直流路径长，拉弧机率大，易起火灾 运维 熔丝、风扇需要定期维护，工作量大，逆变器坏了维修、更换周期长 无熔丝、外置风扇，免巡检，设备更换简单 熔丝、风扇需要定期维护，工作量大，逆变器坏了维修、更换周期长 "环境 保护" "水泥基础不利于环境恢复，造成 永久性破坏" 无逆变器房 "水泥基础不利于环境恢复，造成 永久性破坏" "智能 管理" 缺少集中化管理平台，运维人员技能水平要求高，无法远程协 "智能运维、智能检测、降低运 维人力成本 50%" 缺少集中化管理平台，运维人员技能水平要求高, 无法远程协| 方案 | 集中式方案 | 组串式智能光伏解决方案 | 集散式方案 | | :---: | :---: | :---: | :---: | | 地形适应 | 2～4路 MPPT，对地形适应性较差 | 多路 MPPT，适合山地复杂地形，发电量提升 3%以上 | 多路 MPPT，适合山地复杂地形，发电量提升 2%以上 | | 设计 | 设计标准化，方案成熟 | 需针对不同方阵进行设计，设计难度较大 | 设计标准化，方案成熟 | | 承重 | 安装较复杂，需要专业重型设备 | 重量较轻, 易于安装, 可直接固定于光伏支架上，无需独立 <br> 基础 | 安装较复杂，需要专业重型设备 | | 通讯 | 采用光纤传输，需要进行开挖埋设 | 可采用无线通信方案也可采 <br> 用光纤传输方案 | 采用光纤传输，需要进行开挖埋 <br> 设 | | 安全 | 直流路径长，拉弧机率大，易起火灾 | 直流路径短，更安全 | 直流路径长，拉弧机率大，易起火灾 | | 运维 | 熔丝、风扇需要定期维护，工作量大，逆变器坏了维修、更换周期长 | 无熔丝、外置风扇，免巡检，设备更换简单 | 熔丝、风扇需要定期维护，工作量大，逆变器坏了维修、更换周期长 | | 环境 <br> 保护 | 水泥基础不利于环境恢复，造成 <br> 永久性破坏 | 无逆变器房 | 水泥基础不利于环境恢复，造成 <br> 永久性破坏 | | 智能 <br> 管理 | 缺少集中化管理平台，运维人员技能水平要求高，无法远程协 | 智能运维、智能检测、降低运 <br> 维人力成本 $50 \%$ | 缺少集中化管理平台，运维人员技能水平要求高, 无法远程协 |
 programmatic  Centralized solutions  String Smart PV Solutions  Decentralized solutions
 Assist.  Assist.
方案 集中式方案 组串式智能光伏解决方案 集散式方案 助。 助。| 方案 | 集中式方案 | 组串式智能光伏解决方案 | 集散式方案 | | :---: | :---: | :---: | :---: | | | 助。 | | 助。 |
 Comparison table of three inverter investments
 Table 5.1.2-2
 serial number  sports event  centralized  stranded  distributed  Comparative results
1  inverter 低

High About $0.12/w higher than centralized
高 较集中式高约 0.12 元/w| 高 | | :--- | | 较集中式高约 0.12 元/w |

Weight 4 cents/w higher than centralized
重 较集中式高 4 分/w| 重 | | :--- | | 较集中式高 4 分/w |
  Centralized, hub-and-spoke equivalent
2  convergence box 中  Lower than centralized 1～2 cents/w  3 cents/w higher than centralized  string excellence
3  Booster box-type substation 高  Lower than centralized 4.5 cents/w  2 cents/w lower than centralized  string excellence
4  (electric) cable 高  4 cents/w lower than centralized

Low 4 cents/w lower than centralized
低 较集中式低 4 分/w| 低 | | :--- | | 较集中式低 4 分/w |
  distributed superiority
5  add up the total  standard of reference  13 cents/w higher than centralized  1 cent/w higher than centralized
序号 项目 集中式 组串式 集散式 对比结果 1 逆变器 低 "高 较集中式高约 0.12 元/w" "重 较集中式高 4 分/w" 集中式、集散式相当 2 汇流箱 中 低较集中式低 1～2分/w 较集中式高 3 分/w 组串式优 3 升压箱式变电站 高 低较集中式低 4 5 分/w 较集中式低2 分/w 组串式优 4 电缆 高 较集中式低 4 分/w "低 较集中式低 4 分/w" 集散式优 5 合计 基准 较集中式高 1 3 分/w 较集中式高1 分/w | 序号 | 项目 | 集中式 | 组串式 | 集散式 | 对比结果 | | :---: | :---: | :---: | :---: | :---: | :---: | | 1 | 逆变器 | 低 | 高 <br> 较集中式高约 0.12 元/w | 重 <br> 较集中式高 4 分/w | 集中式、集散式相当 | | 2 | 汇流箱 | 中 | 低较集中式低 1～2分/w | 较集中式高 3 分/w | 组串式优 | | 3 | 升压箱式变电站 | 高 | 低较集中式低 4 5 分/w | 较集中式低2 分/w | 组串式优 | | 4 | 电缆 | 高 | 较集中式低 4 分/w | 低 <br> 较集中式低 4 分/w | 集散式优 | | 5 | 合计 | 基准 | 较集中式高 1 3 分/w | 较集中式高1 分/w | |

From Table 5.1.2-2, the string inverter has the highest upfront investment among the three types of inverters, while the centralized inverter has the lowest upfront investment. The string inverter and the centralized inverter have the multiple MPPT function, which can increase the power generation by 3 % 3 % 3%3 \% and 2 % 2 % 2%2 \% compared to the centralized inverter in the site with module mismatch. The string type has the highest static investment per watt, which can improve the amount of power generation more significantly, and the internal rate of return on capital costs, which is the highest among the three types of inverters. Centralized inverter unit watt of the lowest static investment, power generation is also the lowest. The centralized inverter investment cost and yield in the middle of the two.

Comprehensive technical and economic comparison, the centralized inverter scheme has lower investment cost, mature technology, higher market share, and is suitable for large-scale ground-based PV power plants; the string inverter scheme has higher investment cost, multiple MPPTs, and better tracking effect, and is suitable for typical mountainous projects; and the distributed inverter is a combination of the two, with medium investment cost and multiple MPPTs, and is suitable for ground-based and mountainous PV plants, but is less applied at present. It is suitable for terrestrial power plants and mountainous PV power plants, but is less applied at present.

The terrain of this project is flat, the components are oriented in the same direction, there is no shading, and the multi-MPPT scheme cannot effectively improve the power generation efficiency, and the power generation of the system is basically the same, but at this time, the centralized inverter scheme has a lower investment cost and is more advantageous. The centralized inverter scheme is recommended for this project. In order to save civil construction investment, 5000 kW box inverter is recommended for this project, and the final model will be determined according to the next stage of bidding.

 5000 kW box inverter main technical parameters table

 Table 5.1.2-3
 DC Side Parameters
 Maximum Input Voltage 1500V
 MPPT Voltage Range 895 1500V
 Number of input channels  24 28 Optional
 Number of MPPTs 2
 AC Side Parameters
 Rated output power 5000kW
 Maximum inverter output current  6252 (2*3126) A
 Rated output frequency 50 Hz / 60 Hz 50 Hz / 60 Hz 50Hz//60Hz50 \mathrm{~Hz} / 60 \mathrm{~Hz}
 Total Harmonic Content (THD)   < 3 % < 3 % < 3%<3 \% (at rated power)
 Power factor for rated power > 0.99 > 0.99 > 0.99>0.99
 system parameter
 Maximum efficiency > 99.00 % > 99.00 % > 99.00%>99.00 \%
 China Efficiency > 98.57 % > 98.57 % > 98.57%>98.57 \%
 protection class  Transformer body IP65
 Operating Temperature − 35 ∼ + 60 ∘ C − 35 ∼ + 60 ∘ C -35∼+60^(@)C-35 \sim+60^{\circ} \mathrm{C}
 Cooling method  Intelligent Liquid Cooling
 Permissible altitude  5000m ( > 3000 m > 3000 m > 3000m>3000 \mathrm{~m} customized)
 weights 15T
直流侧参数 最大输入电压 1500V MPPT 电压范围 895 1500V 输入路数 24 28 可选 MPPT 数量 2 交流侧参数 额定输出功率 5000kW 最大逆变器输出电流 6252（2*3126）A 额定输出频率 50Hz//60Hz 总谐波含量（THD） < 3% (额定功率下) 额定功率的功率因数 > 0.99 系统参数 最大效率 > 99.00% 中国效率 > 98.57% 防护等级 变压器本体 IP65 工作环境温度 -35∼+60^(@)C 冷却方式 智能液冷 允许海拔高度 5000m（ > 3000m 定制） 重量 15T| 直流侧参数 | | | :---: | :---: | | 最大输入电压 | 1500V | | MPPT 电压范围 | 895 1500V | | 输入路数 | 24 28 可选 | | MPPT 数量 | 2 | | 交流侧参数 | | | 额定输出功率 | 5000kW | | 最大逆变器输出电流 | 6252（2*3126）A | | 额定输出频率 | $50 \mathrm{~Hz} / 60 \mathrm{~Hz}$ | | 总谐波含量（THD） | $<3 \%$ (额定功率下) | | 额定功率的功率因数 | $>0.99$ | | 系统参数 | | | 最大效率 | $>99.00 \%$ | | 中国效率 | $>98.57 \%$ | | 防护等级 | 变压器本体 IP65 | | 工作环境温度 | $-35 \sim+60^{\circ} \mathrm{C}$ | | 冷却方式 | 智能液冷 | | 允许海拔高度 | 5000m（ $>3000 \mathrm{~m}$ 定制） | | 重量 | 15T |

 1.2 PV array operation mode selection

 1.2.1 Tracking method selection


Typically the types of PV square array supports are simple fixed supports and relatively complex tracking systems. A tracking system is a device that supports a PV array and moves precisely to minimize the angle of incidence of the sun's incident light onto the surface of the array, and accordingly maximize the incident solar radiation. Trackers can be categorized into "single-axis tracking", "dual-axis tracking", "dual-axis tracking" and "dual-axis tracking".
 There are several types of tracking such as "Tracking" and "Diagonal Axis Tracking". The following figure shows the types of tracking.
 Horizontal single-axis tracking
 Single-axis tracking of inclination and latitude angles
 dual-axis tracking
 Figure 5.1.2-3 Schematic diagram of different PV trackers
 (1) Fixed bracket

The most mature technology, relatively lowest cost and most widely used method of mounting PV modules, considering their installability and safety, is the fixed mounting. This method installs the PV square array according to a fixed angle to the ground and a fixed direction. This method has the advantages of simple installation and low maintenance, but the power generation is lower compared to the auto-tracking type.
 (2) Adjustable tilt angle bracket

Based on the tilt angle adjustable fixed bracket installation of PV square array annual power generation than tilt angle fixed installation of the square array will have a certain increase. Specific project implementation, according to the location of the power station radiation and other meteorological conditions to consider the angle adjustment range, as well as the form of adjustment (continuously adjustable / intermittent adjustable), intermittent adjustable higher stability, relatively low cost. However, its cost is slightly higher than the fixed angle bracket, in addition to the later maintenance costs are relatively high compared to the fixed type, the power station is put into operation, the operating costs are relatively high compared to the fixed type.
 (3) Single-axis tracking

Single-axis auto-trackers are used to carry conventional flat-plate PV modules and can increase average daily power generation by 20 35%. If the angle between the rotating axis of the single axis and the ground is 0 degrees, then it is horizontal single-axis tracking; if the rotating axis of the single axis is inclined to the ground at a certain angle, and the azimuth angle of the PV module is not 0, then it is called polar-axis single-axis tracking. For the region of 30-40 degrees north latitude, the use of horizontal single-axis tracking can increase the power generation capacity of about 15 % 15 % 15%15 \% , and the use of polar single-axis tracking can increase the power generation capacity of about 35 % 35 % 35%35 \% . However, compared with the horizontal single-axis tracking, the stent cost of the polar single-axis tracking is higher, and the wind resistance is relatively poor, so the general single-axis tracking system mostly adopts the horizontal single-axis tracking method.
 (4) Dual-axis tracking

Dual-axis tracking is a tracking method that allows movement in both azimuth and tilt directions. Dual-axis tracking systems can maximize the utilization of sunlight by PV modules. Dual-axis tracking system in different places, different weather conditions, to improve the degree of PV module power generation is also different: in a very cloudy and a lot of fog, the use of dual-axis tracking can improve power generation by 20 25%; in a relatively sunny place, the use of dual-axis tracking system, power generation can be increased 35 % ∼ 45 % 35 % ∼ 45 % 35%∼45%35 \% \sim 45 \% .

For tracking systems, the total solar radiation received on the inclined plane is maximized, thus increasing the amount of power generated, but increasing the failure rate and maintenance costs.

 Comparison table of several types of photovoltaic mounts

 Table 5.1.2-4
 Comparative content  set rigidly in place  Fixed adjustable  Horizontal single-axis tracking  dual-axis tracking
 Increase in electricity generation (%) 100 105 112 125

1MW Floor space (10,000 m2)
1MW 占地面积 （万 m2）| 1MW 占地面积 | | :--- | | （万 m2） |
 1.65 1.6 1.34 2.5
 Increase in direct investment (%)
直接投资增加率 (%)| 直接投资增加率 | | :--- | | (%) |
 100 102 107 122
 Racking system operation and maintenance  Essentially maintenance-free  High workload and high operational requirements for bracket adjustment  With rotating mechanism, high failure rate and high actual workload
 Multiple rotating mechanisms for higher failure rates and greater workloads
有多处旋转机构，故障率更高， 工作量更大| 有多处旋转机构，故障率更高， | | :--- | | 工作量更大 |
 Component Support Points  multipoint  multipoint  multipoint  à la carte
 Component Cleaning  Easy to clean  Easier to clean  difficult clean  Low cleaning efficiency and difficulties
 wind resistance  mediocre  mediocre  Automatic adjustment, better
 Applicable solar resources Conditions
适用太阳能资源 条件| 适用太阳能资源 | | :--- | | 条件 |
  unrestricted  Suitable for areas with flat terrain and strong direct radiation
 Reliability and Maturity
 Large market share, mature and reliable
市场占有率大， 成熟可靠| 市场占有率大， | | :--- | | 成熟可靠 |
 Basic reliability, more mature products
基本可靠，产品较 成熟| 基本可靠，产品较 | | :--- | | 成熟 |
  Lower adoption rate, fewer mature and reliable devices
 Extremely low adoption rate, mostly experimental demonstration, few mature and reliable equipment
应用率极低，多为示范试验性， 成熟可靠设备少| 应用率极低，多为示范试验性， | | :--- | | 成熟可靠设备少 |
比较内容 固定 固定可调 水平单轴跟踪 双轴跟踪 发电量增加率 (%) 100 105 112 125 "1MW 占地面积 （万 m2）" 1.65 1.6 1.34 2.5 "直接投资增加率 (%)" 100 102 107 122 支架系统运行维护 基本免维护 支架调整工作量大，操作要求高 有旋转机构，故障率高，实际工作量大 "有多处旋转机构，故障率更高， 工作量更大" 组件支撑点 多点 多点 多点 单点 组件清洗 清洗方便 清洗较方便 清洗不便 清洗效率低，困难大 抗风能力 较差 较差 自动调节，较好 "适用太阳能资源 条件" 不限制 适合地势平坦直接辐射较强的地区 可靠性与成熟度 "市场占有率大， 成熟可靠" "基本可靠，产品较 成熟" 应用率较低，成熟可靠设备较少 "应用率极低，多为示范试验性， 成熟可靠设备少"| 比较内容 | 固定 | 固定可调 | 水平单轴跟踪 | 双轴跟踪 | | :---: | :---: | :---: | :---: | :---: | | 发电量增加率 (%) | 100 | 105 | 112 | 125 | | 1MW 占地面积 <br> （万 m2） | 1.65 | 1.6 | 1.34 | 2.5 | | 直接投资增加率 <br> (%) | 100 | 102 | 107 | 122 | | 支架系统运行维护 | 基本免维护 | 支架调整工作量大，操作要求高 | 有旋转机构，故障率高，实际工作量大 | 有多处旋转机构，故障率更高， <br> 工作量更大 | | 组件支撑点 | 多点 | 多点 | 多点 | 单点 | | 组件清洗 | 清洗方便 | 清洗较方便 | 清洗不便 | 清洗效率低，困难大 | | 抗风能力 | 较差 | 较差 | 自动调节，较好 | | | 适用太阳能资源 <br> 条件 | 不限制 | 适合地势平坦直接辐射较强的地区 | | | | 可靠性与成熟度 | 市场占有率大， <br> 成熟可靠 | 基本可靠，产品较 <br> 成熟 | 应用率较低，成熟可靠设备较少 | 应用率极低，多为示范试验性， <br> 成熟可靠设备少 |