固定安装面积下组件串联数对BOS成本的影响

传统的组件串联数设计主要依据当地的极端温度、系统电压等级测算，并根据实际情况在计算值的基础上增加1至2块组件。 当组件安装面积固定的情况下，组件串联数的取值不同，可能会对系统的BOS成本带来影响，主要的影响因素有长短支架的变化引起的安装容量、线缆、支架及基础等成本的变化。下面就以上海为站点做案例分析。 屋顶的类型为混凝土平屋面，有一定高度女儿墙，屋面上无任何遮挡物。屋面的面积假设5000平方。逆变器选择组串式逆变器，支架选择固定倾角式支架。光伏组件选择166版型475W。根据逆变器的电压等级1100V，当地的环境温度，设计的组件串联数取值可为18块或20块。 使用Candelaroof软件进行布置，可得到阵列的排布图，其中单个支架单元的相邻间距均为1m。 左图是使用18块组件一串，均为长支架（1*18），单个支架的组串数为1串，数量为70套，组件数量为1260块，组件容量为598.5kW； 右图是20块组件一串，长支架（1*20）数量为56套，单个支架的组串数量为1串，短支架数量（1*12）为13套，短支架（1*4）数量1套，短支架前后排通过4平方光伏延长线，以20块组件为一串进行连接，组件数量为1280块，组件容量为608kW。 由布置图纸可见，当使用18块组件为一串时，屋面宽度50m和长度100m，使用长支架可将整个屋面布满。 使用20块组件一串时，由于屋面的宽度有限，布置4列阵列以后，剩余的可利用空间只能使用短支架。 经统计，在容量上比1*18长支架方案增加了1.59%。 在逆变器的选型上，使用120kW逆变器，MPPT数量12路，单台逆变器均接入20串，那么对于长支架方案，组串数量70串，长短支架方案组串数量64串，如果逆变器数量均为4台，那么组串的数量均小于逆变器的可接入数，同时还可实现较为接近的容配比。对于长支架方案，容配比为1.25，对于长短支架方案，容配比为1.27。 使用1*20长短支架方案，由于组串数量下降，在电缆的使用量和成本上有一定的下降。 使用1*18长支架在支架和基础成本上有一定的下降。 当逆变器台数和单台价格相同的情况下，逆变器在直流侧的单瓦成本随着容配比的增加而下降，使用1*18方案，组件的安装容量有一定下降，因此逆变器直流侧的单瓦成本有一定增加。 组件的安装与组件的重量有关，组件的安装价格相同。而支架的安装与数量有关，长支架安装数量有一定下降，单瓦成本略低。 综上系统端的可变BOS成本细项，对于两种组件串联数的方案而言，BOS成本在上述细项的成本进行相加，那么1*18长支架方案略显优势，可比长短支架方案下降0.7分/W。 综上可知，对于固定面积的屋顶分布式光伏电站，若光伏组件的串联数发生变化，对阵列的布置带来一定影响，当全使用长支架或长短支架共存的两种方案，系统电缆、支架、逆变器等成本均会发生变化。 在该案例中当使用1*18支架设计方案有一定优势，而组件串联数增加2块后，在线缆成本、容量上均有一定优势，但是却带来支架、基础成本的增加。 因此我们在做具体的项目设计时，不能单纯依靠组件串联数的计算公式，还需要依据屋面面积等情况进行排布，通过不同方案的测算，得出最合理的设计。

组件离地高度对分布式光伏项目收益的影响

商业综合体女儿墙普遍较高，屋顶设备较多。在这种情况下，组件离地高度会影响项目的布置容量、造价、发电量和收益，因此需要结合项目实际情况进行综合比较。 本文采用CandelaRoof软件，以江苏常州某300kW低压并网项目为例，对组件离地高度与收益率的关系进行分析。该项目采用自发自用、余电上网模式，综合自用电价0.796元/kWh，自发自用率90.3%。需要说明的是：本文的分析结论只适用于个案。 01 方案1：组件最低点离地高度0.5米，布置倾角25° 1）经软件计算：按冬至日上午9点-下午3点，阴影遮挡范围（红色虚线内区域）面积为275㎡，占比10.24%。 2）对可用区域布置545组件，倾角25°，共布置512块，容量279.04kWp。 3）创建支架和基础。（组件最低点离地高度0.5米） 4）每20块组件构成1串（个别16块1串），采用5台50kW逆变器汇流接入并网点，容配比1.12。 02 方案2：组件最低点离地高度1.5米，布置倾角23° 注：本案例假设支架立柱、横梁等部件的截面不变，只是立柱高度提高 1）经软件计算：按冬至日上午9点-下午3点，阴影遮挡范围面积为0㎡（因为沿着女儿墙四周已预留1米通道）。 2）对可用区域布置545组件，倾角23°，共布置600块，容量327.00kWp。 3）创建支架和基础。（组件最低点离地高度1.5米） 4）每20块组件构成1串，采用5台50kW逆变器汇流接入并网点，容配比1.31。 03 采用CandelaRoof软件的方案比选功能，选中上述两个文件之后，导出方案对比结果如下： 方案1-离地0.5米 方案2-离地1.5米 一、设计条件 气象数据来源 Meteonorm Meteonorm 水平面年总辐射(kWh/㎡) 1247.00 1247.00 组件型号 LR5-72 HPH-545M LR5-72 HPH-545M 逆变器型号 SG50CX SG50CX 容配比 1.12 1.31 汇流方式及并网点数量 A.组串逆变器-并网点(1个) A.组串逆变器-并网点(1个) 方阵实际倾角(°) 25 23 方阵实际方位角(°) 0 0 方阵离地高度(m) 0.5 1.5 方阵间距（平屋顶）(m) 3.9 3.8 二、设计输出概要 布置容量(kWp) 279.04 327.00 造价(元) 1159524.00 1359654.57 造价(元/W) 4.16 4.16 发电量(kWh) 301454.88 355922.48 发电量(kWh/kWp) 1080.33 1088.45 全部投资内部收益率(所得税后)(%) 13.99 14.27 自有资金内部收益率 (%) 19.54 20.17 三、主要设备材料比较 组串出线电缆长度(m) 1508.65 1830.95 一级汇流电缆长度(m) 275.76 280.48 其他电缆长度(m) 0.00 0.00 彩钢瓦支架(kg/kWp) 0.00 0.00 水泥屋顶支架(kg/kWp) 21.78 26.01 四、首年PR比较(%) 阴影损失 3.41 2.62 入射损失 2.15 2.17 污秽损失 3.00 3.00 弱光损失 1.00 1.00 温度损失 3.37 3.39 组件功率偏差 -0.40 -0.40 第1年组件衰减 0.28 0.28 LID损失 1.60 1.60 失配损失 1.20 1.20 交直流线损 0.94 0.93 逆变器损失 1.50 1.50 自用电 0.50 0.50 不可利用率 1.50 1.50 变压器损失 0.00 0.00 双面增益 0.00 0.00 PR 81.17 81.81 五、造价分项比较(元/W) 设备购置费 光伏组件 2.00 2.00 光伏支架 0.21 0.25 交流/直流汇流箱 0.00 0.00…

Is the production slightly higher when arranged following the slope compared to the normal arrangement?

The author received a consultation: for a project in Guangxi, the yield (referring to the yield per kilowatt, the same below) of electricity generated by following the slope is surprisingly slightly higher than that when arranged directly facing south. After conducting Production calculations for two layout plans using Candela3D and PVsyst software, the Simulate results have verified the correctness of the conclusions. What exactly is the reason for that? The author has conducted an analysis on the actual terrain layout of the project, and the results are as follows: In the table above, the four normals highlighted in red account for nearly 70% of the total. Next, we will calculate the actual tilt and azimuth angles of the array for these four normals, using both due south and downslope arrangements, and employ PVsyst to compute the annual total radiation. It can be observed that for the aforementioned four orientations, when…

The new generation of arrays layout module for complex terrain projects has been launched

The previous issue of "Hill-shading analysis method for complex terrain" addressed the issue of selecting sunshine regions in complex terrains. However, how to arrange arrays as much as possible within a limited area while ensuring maximum production is a highly complex problem. We cannot simply consider this issue in terms of the front row not blocking the back row during a certain period of time (although this is a conventional approach, the result is insufficient land utilization and the plan is not economical). We need to consider many issues, such as: 1) Partial arrays are allowed to be obscured, allowing for a more compact array layout; 2) If some scattered arrays block the back row, even if they are not obscured by the front row, deleting them can make the arrangement of the back row more tidy; 3) Mutual obstruction and sequence of layout between adjacent areas (such as front…

Next-generation Hill-shading analysis method for complex terrain

For projects with complex terrain, the most crucial step when selecting an available area is to find areas that meet the sunlight conditions. The conventional method for sunshine filtering typically follows the principle of not being blocked by other mountains from 9 am to 3 pm throughout the year. When the arrangement capacity is insufficient, the time range will be shortened. There are the following issues with this analysis method: 1. It can only conduct preliminary quantitative analysis of direct radiation, but cannot analyze the scattering and reflection losses caused by mountain obstruction; 2. For complex terrain, the sunshine periods of the mountains are not symmetrical, making it difficult to handle; 3. It is not possible to Analyze the occlusion loss outside the specified time period. The new generation of Hill-shading analysis method directly targets the ultimate goal of Hill-shading analysis, which is to select the areas that receive the…

Discussion on the East-West Spacing of Photovoltaic Arrays in Mountainous Areas

The spacing between PV arrays in the E-W Direction, as the name suggests, is as shown in the figure below. It seems that there is no room for discussion, so it is often skipped. However, the actual layout process of a project in Complex terrain is not as straightforward as it seems. This is mainly due to the following two reasons: 1)The arrays are arranged according to the terrain, and as the length and width of the array's projection change, the shape of the Parallelogram also changes; 2)Traditional drawing still treats arrays as unchanging rectangles for layout. For the above item 1), to control the actual East-west spacing to a set value (such as 0.5 meters), it can be achieved through a step-by-step method. This is actually not difficult. Regarding the aforementioned point 2), it is actually the reason that complicates the issue. From a two-dimensional projection, the actual arrays…