Pamukkale Univ Muh Bilim Derg. Ahead of Print: PAJES-24896 | DOI: 10.5505/pajes.2023.24896

Electrical sizing of grid-connected photovoltaic systems

Ahmet Ilýca¹, Muhammed Serdar^2
1Department Of Electricity And Energy, Kütahya Dumlupýnar University, Kütahya, Turkey
²Sms Energy Consulting R&d Engineering Limited Company, Denizli, Turkey

It is of great importance to choose low-cost, high-performance/efficient and operating and protection equipment in accordance with the applicable legislation in electrical facilities. It is necessary to make calculations for the selection of the most suitable cable/line, measuring and protection system equipment. In this study, panel-inverter compatibility calculation, voltage drop, current control, short circuit, lightning risk and protection calculations, grounding resistance and grounding conductor calculations and tilt angle calculation were made for a grid connected photovoltaic system with a power of 0.4 MWe. It has been calculated that the allowable voltage range and maximum powerpoint voltage values of the selected inverter are compatible with the panel system. With voltage drop and current control calculations, copper cable cross section for each inverter output and solar board output were found to be 3x70+35 mm2 and 2(3x185+95) mm2, respectively, and transformer low voltage busbar 60x10 mm2. In order not to deform the low voltage busbars in peak short-circuit current, they should be placed at 10 cm intervals for 80 cm length. According to the transformer low voltage side phase-earth short circuit current, the cross-section of the grounding conductor should be at least 53.97 mm2 copper conductor. In the lightning protection facility of the panels, according to the rolling sphere method, it has been calculated that the air termination rods should be at least 0.84 m above the upper point of the solar panel. The optimum fixed panel tilt angle was found to be 32.08°. The calculations used in the study will benefit the practitioners in the design of grid-connected photovoltaic systems, in the selection of the most suitable electrical equipment with minimum size.

Keywords: Grid connected photovoltaic system, voltage drop, short circuit calculation, lightning protection, tilt angle

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Þebekeye baðlý fotovoltaik sistemlerin elektriksel boyutlandýrýlmasý

Ahmet Ilýca¹, Muhammed Serdar^2
1Kütahya Dumlupýnar Üniversitesi Simav Meslek Yüksekokulu, Elektrik Ve Enerji Bölümü, Kütahya
²Sms Enerji Danýþmanlýk Arge Mühendislik Limited Þirketi, Denizli

Elektrik tesislerinde düþük maliyetli, yüksek performanslý/verimli ve ilgili mevzuata uygun iþletme ve koruma ekipmanlarýnýn seçilmesi büyük önem taþýmaktadýr. En uygun kablo/hat, ölçüm ve koruma sistemi ekipmanlarýnýn seçimi için hesaplamalar yapýlmasý gerekmektedir. Bu çalýþmada, þebeke baðlantýlý 0,4 MWe gücünde bir fotovoltaik sistem için panel-evirici uyumluluk hesabý, gerilim düþümü, akým kontrolü, kýsa devre, yýldýrým risk ve koruma hesaplarý, topraklama direnci ve topraklama iletkeni hesaplarý ve panel eðim açýsý hesabý yapýlmýþtýr. Seçilen eviricinin izin verilen voltaj aralýðý ve maksimum güç noktasý gerilim deðerlerinin panel sistemi ile uyumlu olduðu hesaplanmýþtýr. Gerilim düþümü ve akým kontrol hesaplarý ile her evirici çýkýþý ve güneþ sistemi panosu çýkýþý için bakýr kablo kesiti sýrasýyla 3x70+35 mm2 ve 2(3x185+95) mm2, trafo alçak gerilim barasý 60x10 mm2 olarak bulunmuþtur. Alçak gerilim baralarýnýn tepe kýsa devre akýmýnda deforme olmamasý için 80 cm boy için 10 cm aralýklarla yerleþtirilmelidir. Trafo alçak gerilim tarafý faz-toprak kýsa devre akýmýna göre topraklama iletkeninin kesiti en az 53,97 mm2 bakýr iletken olmalýdýr. Panellerin yýldýrýmdan korunma tesisinde yuvarlanan küre yöntemine göre, hava yakalama uçlarýnýn güneþ panelinin üst noktasýndan en az 0,84 m yukarýda olmasý gerektiði hesaplanmýþtýr. Optimum sabit panel eðim açýsý 32,08° bulunmuþtur. Çalýþmada kullanýlan hesaplamalar, þebeke baðlantýlý fotovoltaik sistemlerin tasarýmýnda, minimum boyutta en uygun elektriksel donanýmýn seçiminde uygulayýcýlara fayda saðlayacaktýr.

Anahtar Kelimeler: Þebekeye baðlý fotovoltaik sistem, gerilim düþümü, kýsa devre hesabý, yýldýrýmdan koruma, eðim açýsý

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