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每相并聯(lián)電纜的校正系數(shù)：大值
表2（TN系統(tǒng)）或表3（IT系統(tǒng)）中讀取的保護長度應(yīng)為
乘以以下系數(shù)：
n 2 3 4 5 6 7 8
kp 2 2.7 3 3.2 3.3 3 3.4 3.5
n是每相并聯(lián)的導(dǎo)體數(shù)量
三相電壓不同于400 V的校正系數(shù)：的值
表2（TN系統(tǒng)）或表3（IT系統(tǒng)）中讀取的大保護長度
應(yīng)乘以以下系數(shù)：
電壓【V】230 400 440 500 690
kV 0.58 1 1.1 1.25 1.73
對于230 V單相系統(tǒng)，無需校正系數(shù)。
鋁制電纜的修正系數(shù)：大保護值
表2（TN系統(tǒng)）或表3（IT系統(tǒng)）中讀取的長度應(yīng)乘以
以下因素：
kAl 0.64
保護導(dǎo)體橫截面修正系數(shù)SPE不同
根據(jù)表1中規(guī)定的橫截面：大保護長度的值應(yīng)乘以對應(yīng)于相位的系數(shù)
導(dǎo)體橫截面和保護導(dǎo)體之間的比率（PE）
以及相位橫截面：
SPE/S 0.5 0.55 0.6 0.66 0.75 0.87 1 1 1.25 1.5 2
S kPE
≤16 mm2 0.67 0.71 0.75 0.80 0.86 0.93 1.00 1.11 1.20 1.33
25 mm2 0.85 0.91 0.96 1.02 1.10 1.19 1.28 1.42 1.54 1.71
35 mm2 1.06 1.13 1.20 1.27 1.37 1.48 1.59 1.77 1.91 2.13
>35 mm2 1.00 1.06 1.13 1.2 1.29 1.39 1.5 1.67 1.8 2.00
IT系統(tǒng)中分布的中性點校正系數(shù)（僅適用于表3）：
大保護長度值應(yīng)乘以0.58。
464電氣設(shè)備| ABB
5座光伏電站
光伏（PV）發(fā)電廠直接瞬時轉(zhuǎn)換太陽能
在不使用任何燃料的情況下轉(zhuǎn)化為電能。事實上，光伏（PV）技術(shù)利用了光電效應(yīng)，通過光電效應(yīng)
適當(dāng)“摻雜”的半導(dǎo)體在暴露于太陽能時發(fā)電
輻射
光伏（PV）電站的主要優(yōu)勢可總結(jié)如下：
•必要時進行分布式發(fā)電；
•無污染材料排放；
•節(jié)約化石燃料；
•設(shè)備的可靠性，因為它們沒有活動部件（使用壽命
通常超過20年）；
•降低運營和維護成本；
•系統(tǒng)模塊化（為了增加電廠功率，足以提高
面板數(shù)量）根據(jù)用戶的實際要求。
然而，由于
從技術(shù)和經(jīng)濟角度來看尚未完全成熟的市場
觀點。此外，由于可變性，發(fā)電不穩(wěn)定
太陽能的能量。
光伏電站的年電力輸出取決于不同的因素。
其中：
•安裝現(xiàn)場的太陽輻射事件；
•面板的傾斜和方向；
•是否有陰影；
•電廠組件的技術(shù)性能（主要是模塊和
逆變器）。
光伏電站的主要應(yīng)用包括：
1.為與電網(wǎng)隔離的用戶安裝（帶存儲系統(tǒng)）；
2、接入低壓電網(wǎng)的用戶裝置；
3.太陽能光伏發(fā)電廠，通常連接到中壓電網(wǎng)。
上網(wǎng)電價優(yōu)惠僅適用于2類和3類應(yīng)用，
額定功率不低于1 kW的電廠。
光伏發(fā)電廠基本上由發(fā)電機（光伏板）和
將面板安裝在地面、建筑物或任何建筑物上的框架
結(jié)構(gòu)，通過功率控制和調(diào)節(jié)系統(tǒng)，通過可能的能量
存儲系統(tǒng)，通過配電盤和開關(guān)設(shè)備組件外殼
開關(guān)和保護設(shè)備以及連接電纜。

Correction factor for cable in parallel per phase: the value of the maximum protected length read in Table 2 (TN system) or Table 3 (IT system) shall be multiplied by the following factor: n 2 3 4 5 6 7 8 kp 2 2.7 3 3.2 3.3 3.4 3.5 n is the number of conductors in parallel per phase Correction factor for three-phase voltage different from 400 V: the value of the maximum protected length read in Table 2 (TN system) or Table 3 (IT system) shall be multiplied by the following factor: voltage [V] 230 400 440 500 690 kV 0.58 1 1.1 1.25 1.73 For 230 V single-phase systems, no correction factor is necessary. Correction factor for aluminium cables: the value of the maximum protected length read in Table 2 (TN system) or Table 3 (IT system) shall be multiplied by the following factor: kAl 0.64 Correction factor for protective conductor cross section SPE different from the cross sections stated in Table 1: the value of the maximum protected length shall be multiplied by the coefficient corresponding to the phase conductor cross section and to the ratio between the protective conductor (PE) and the phase cross sections: SPE/S 0.5 0.55 0.6 0.66 0.75 0.87 1 1.25 1.5 2 S kPE ≤16 mm2 0.67 0.71 0.75 0.80 0.86 0.93 1.00 1.11 1.20 1.33 25 mm2 0.85 0.91 0.96 1.02 1.10 1.19 1.28 1.42 1.54 1.71 35 mm2 1.06 1.13 1.20 1.27 1.37 1.48 1.59 1.77 1.91 2.13 >35 mm2 1.00 1.06 1.13 1.2 1.29 1.39 1.5 1.67 1.8 2.00 Correction factor for neutral distributed in IT systems (for Table 3 only): the value of the maximum protected length shall be multiplied by 0.58. 464 Electrical devices | ABB 5 Photovoltaic plants A photovoltaic (PV) plant transforms directly and instantaneously solar energy into electrical energy without using any fuels. As a matter of fact, the photovoltaic (PV) technology exploits the photoelectric effect, through which some semiconductors suitably “doped” generate electricity when exposed to solar radiation. The main advantages of photovoltaic (PV) plants can be summarized as follows: • distribuited generation where needed; • no emission of polluting materials; • saving of fossil fuels; • reliability of the plants since they do not have moving parts (useful life usually over 20 years); • reduced operating and maintenance costs; • system modularity (to increase the plant power it is sufficient to raise the number of panels) according to the real requirements of users. However, the initial cost for the development of a PV plant is quite high due to a market which has not reached its full maturity from a technical and economical point of view. Moreover the generation of power is erratic due to the variability of the solar energy source. The annual electrical power output of a PV plant depends on different factors. Among them: • solar radiation incident on the installation site; • inclination and orientation of the panels; • presence or not of shading; • technical performances of the plant components (mainly modules and inverters). The main applications of PV plants are: 1.installations (with storage systems) for users isolated from the grid; 2. installations for users connected to the LV grid; 3.solar PV power plants, usually connected to the MV grid. Feed-in Tariff incentives are granted only for the applications of type 2 and 3, in plants with rated power not lower than 1 kW. A PV plant is essentially constituted by a generator (PV panels), by a supporting frame to mount the panels on the ground, on a building or on any building structure, by a system for power control and conditioning, by a possible energy storage system, by electrical switchboards and switchgear assemblies housing the switching and protection equipment and by the connection cables.