Common accidents in Photovoltaic Power Plants (PVPP)

Construction types – norms

  • ORDINANCE No1 of 30 July 2003
  • Article 6, paragraph 5: (amended, SG, volume 23 of 2011 and volume 98 of 2012) Third category constructions types,
  • item  „d”,  are the buildings and facilities of power plants, including those for combined production of electricity and heat, heating plants, installations for the utilization of waste heat and renewable energy sources with a capacity of up to 25 MW inclusive, except for energy production facilities under Article 147, paragraph 1, item 14 of the Spatial Planning Act.

… and what does the reference to the law say?!:

  • Article 147(1) (amended – SG, volume 65 of 2003) No approval of investment projects is required for the issuance of a building permit for:
  • 14. (new – SG, volume 35 of 2011, effective from 03.05.2011) installation of facilities for the production of electricity, heat and/or cooling energy from renewable sources with a total installed capacity of up to and including 30 kW to existing buildings in urbanized areas, including on their roof and facade structures and in their own land properties.

Construction types

 

  1. Photovoltaic panels can be arranged horizontally or vertically, which determines the type of construction, respectively Landscape or Portrait.
  2. Depending on the place of installation, constructions are ground-mounted and roof-mounted.

According the design „… Connections between the aluminium purlins and the steel frames are made under detail B

Design (left) and actual implementation (right);

Connections between the aluminium purlins and the steel frames were not implemented according to the design. The structure has been changed and does not comply with the evidentiary tests for load-bearing capacity under regulatory loads and impacts.

According the design „… Connections at positions 28 and 29 of the design are made by means of a bolt M10, nut, washer and washer. All steel parts should be galvanized… ”

Not all used steel parts, including fasteners are galvanized. Some of the joints and connections made in the structure do not correspond to the design provisions. The welds performed on the main load-bearing steel elements of the structure contradict the design provisions regarding their implementation.

Overloading led to cracking of the material (foci of destruction), corrosion under the influence of tensile and torsional stresses contributed to the development of cracks and rupture occurred at both ends. The part has also been subjected to changing loads, resulting in worn areas. There is only a small solid section of the plate left, judging by the size of the crack, which occupies almost the entire remaining section, the nominal stresses significantly exceeded the capabilities of the remaining section of the part, and it finally destroyed.

The rupture of the plate caused the system to resonate, which resulted in destruction.

The provided factory welds are performed as assembly ones, and they are not at the provided places:

Planned factory weld (internal weld seam), implemented – assembly point weld connection.
122.4 km/h = 34 m/s ; 54 km/h = 15 m/s; Wind load is in the range of 30 – 50 m/s depending on the region.

20 – ZSD module – middle retaining bracket 30-50 mm
21 – ZSD module – end retaining bracket 35 mm module shoulder
22 – bolt M8x80 no security teeth
23 – гайка M8 with inner security teeth
24 – washing S8

End retaining bracket (left); Middle retaining bracket (right);

Part No1 Construction structures

A series of stationary modules for a photovoltaic system have been built.
Stationary modules of the photovoltaic system are 30° tilted to the horizon.

The construction of the photovoltaic power plant was implemented according to the approved designs and revisions during construction. With the initial approval of the Technical Investment Design, it was planned that the construction of the power plant would be made of cold-bent steel profiles and aluminium profiles from the company Krinner. The foundation of the metal profiles according to the initial design was provided to rest on single round welds of the same company with a diameter of 60 mm and a driving depth of 1.50 m. Reinforcing diagonals with ø 34 mm were also provided..

Changing result in metal structure made entirely of cold-bent profiles. The foundation made of single cylindrical foundations with d = 250 mm and height 100 cm. The vertical profiles penetrate at least 60 cm into the foundations.

Metal structure elements are a complete supply and are accompanied by the necessary documentation.

Complex concreate transformer post is a completely finished product and is delivered free of charge to the client site by transport of “Pavel and Sons Electric” OOD.

Only a monolithic reinforced concrete foundation was built on site. Under the main plane of the foundation, a 10 cm thick B10 concrete base was laid. Above the base concrete, a double reinforcing mesh (lower) of ø 6.5/ 20 cm, square, was installed. The foundation body was cast from B20 concrete with a horizontal upper surface.
but nothing is mentioned about the method of attaching the modules to the finished metal structure.

B. According the implementation of construction and installation works;

The construction is:

B.1.1. Photovoltaic system for the production and consumption of energy, produced from a renewable energy source – the sun, located on the terrain located in Zoned Land УПИ III – 4, plot 124, Ashiklare locality, Zetovo village, Chirpan municipality, Stara Zagora region.

The construction was implemented on the basis of an approved comprehensive design and design documentation approved by the Chirpan Municipality. The design was prepared in accordance with Article 150 of the Spatial Planning Act and contains an amendment to an article on regulation and development and an investment project for a photovoltaic system in the technical phase.

B2.1. Part Architecture
The installation of the photovoltaic modules was performed on the existing steel structure tower, with the modules oriented south with a tilt of 30 degrees.

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