63kW Ground mounted solar power plant


Area:Stara Zagora
In operation since:22.04.2011
  • SMA
  • Huber+Suhner AG
  • Alcomet
  • Solar Swiss
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The photovoltaic system is built of mono-crystalline type Solar Swiss SSM-170/24М. The nominal voltage of these modules is 24,0 V and 170W.

The power plant consists of 378 modules divided into 9 groups. Each group consists of 42 modules divided into 3 strings of 14 modules. The groups feed the generated electricity to inverter. For the current project are used SMA Technologies inverters, Sunny Mini Central SMC 7000TL model. The inverters are single-phase with inputs for 3 strings, without transformers and with high Energy conversion efficiency. From each inverter exits a СВТ-c 2х16мм2  cable and goes to a properly sized circuit breaker into intermediate switchboard. The intermediate switchboards are three. There are 3 inverters connected to each intermediate switchboard. From Intermediate switchboard 1, Intermediate switchboard 2, Intermediate switchboard 3 exits a СВТ-с 4х16ммcable and goes to a properly sized circuit breaker into main switchboard The main switchboard powers also a warning light, voltmeters, ammeters, outlet and UPS. Cathode surge arresters are provided against atmospheric excess voltage given the high cost of the investment.

For earthing devices are used galvanized pipes 2” with length of 2m. All earthing devices are connected with each other in a closed circuit of galvanized 40/4 mm bar, laid at a depth of 0.4m underground.

The lightning protection system consists of early streamer emission lightning conductor Е.S.E.S-A1 with advance time of 60 µs and lightning shaft height of 3m above the ground. The lightning conductor is located at a distance of 6.4 m of the power plant.

The central monitoring and control device is Sunny Web Box. The device power is implemented via UPS, located in a main switchboard. The monitoring and control devices are installed in a low voltage switchboard.