By Jason Abbott

Often people look across the landscape of a wind farm and are amazed at the size of the turbines and wonder how these giants are constructed. They might ponder how the electricity is generated in each of the turbines, collectively gathered and distributed across an electrical system to different homes.

Wind farm developers spend considerable time developing their projects. Once they have their project fully permitted and developed, they will proceed with the next step—which is the actual construction of a wind farm. The owner/developer will usually contract directly with manufacturers for the large, long lead time pieces of equipment for a particular project. These items typically consist of the towers, blades, turbines, and transformers. 

Construction of a wind farm is predominately completed in one of two methods...

 The owner/developer will contract directly with individual contractors for the completion of the roads, foundations, collection system, and substation; or,
2. The owner/developer will contract with a large general contractor to provide a turnkey project. The GC will complete all the work necessary to complete the project.

1.

Electrical construction is one of the most important parts of the wind farm. With the construction of any wind power project, there are key factors to consider when providing for the electrical system:

Design and layout of the project. The layout of a project is determined by land leases, terrain, prevailing winds, and any other obstacles that may be present at a particular location.

Collection system routing. This is based on the design and layout of a wind farm, as well as on other factors such as the length of runs and the number of turbines on a circuit.

Construction process. The construction of a wind farm requires a great deal of coordination with each of the parties involved. The construction process is completed in logical sequence, and one little glitch can cause multiple delays that may affect the completion date set by an owner or developer.

Electrical components. The electrical construction of a project is integrally tied to all the other parts of the project, and involves constant coordination and communication with the other parties involved. The electrical contractor will have crews of people working in multiple areas throughout the jobsite, and they will be…

Installing the ground grid work, which is done while working in conjunction with the contractor who is completing the tower foundations. As the foundations are being constructed, the electrical contractor will install the PVC conduits that will be part of the completed foundation. These conduits will be utilized to run power and fiber optic cable for each wind turbine.

Another crew will complete the work necessary to install the pad mount transformers at each wind tower site. This process will involve the excavation for, and the placing of a cement pad and box pad structure for the pad mount transformer to sit on. Yet another crew will work on what is called the “electrical collection system.” This crew is responsible for the installation of all the electrical lines—from each of the wind towers to the substation—where all the electricity produced will be sent. The installation involves the electrical cables being placed in the ground. The underground installation is performed in one of two ways:

1. Trenching: A special machine is required with a rotating digging chain located on the rear of the machine, and it places the electrical cable in the “trench.” This is a continuous process where the cables are then covered.
2. Plowing: This method uses a large track machine with a blade mounted on the rear of the machine. It rips a trench into the ground. This is also a continuous process and the cables are covered.

There is a crew that follows the collection installation crew to work on all of the terminations that are needed to tie the wind tower to the collection line, so as to send the energy from the wind farm to the destination point within the substation. All of the collection system U/G cables are brought to the main substation where they will be terminated and connected to the utility system. The electrical contractor will provide the construction of the wind farm substation/interconnect, and that team builds or expands the substation/interconnect for the wind farm. This is an important piece as the substation/interconnect is the final point of all collection of energy before it is transmitted to the main line.

Energizing the wind farm is an exciting part of the entire process. It is one of the last steps in a project, and its completion brings the project full circle. Energizing the wind farm is a process that is very detailed and performed in several steps, with great care, to ensure proper performance of all the components of the wind farm project.

Electrical construction is a critical part of a wind farm. Although each wind farm is unique in its size, and has a unique design, the components of the electrical construction stay consistent.

Aevenia, Inc.
www.aevenia.com