Mike Dolt Enterprises
Mike Dolt Enterprises
User: Matthew_B, Location: NE Arkansas
Asked on: Thursday, March 31, 2011 at 2:05 pm EDT
Answered on: Tuesday, May 14, 2024 at 3:34 am EDT
Question: I work for a wind turbine company doing mid size turbine installs on farms or industrial properties. A big deal for many of these projects is dealing with the long runs between the turbines and the existing service.Traditionally if I was doing work where I had to get power 1000-2000 feet from existing power, it would be time to talk to the power company and get a new service put in near the new load. But we have the unique requirement that since we're offsetting the customer's load, we must be tying into the customer's panel where we will be downstream from the utility meter.I'm wondering if someone here has experience / advice at looking at installing step up and step down pad mount transformers for the runs? Any idea where the cost break-over would be?In most cases the power level is around 50kW to 120kW. On our end of the equipment we can connect at either 240V or 480V. So far we've done a few where fortunately the customer had 480V and then the run is more reasonable. But now we are looking at several where the farm has 240V delta.. and 50+ kW going 1000+ feet gets beyond nuts for the wire.
Transformer Considerations for Long Power Runs
Installing step-up and step-down transformers can be a viable solution for long power runs between wind turbines and customer panels. The cost break-over point will vary depending on factors such as: Power level Distance Wire type and size Transformer efficiency and costCost Analysis
To determine the cost break-over point, compare the cost of the transformer system to the cost of installing a new service from the power company. Consider the following: Transformer cost
Includes the purchase price, installation, and any required accessories (e.g., switches, fuses).
Wire cost
Determine the wire size and type required for both options.
Labor cost
Installation of the transformer system will typically require less labor than installing a new service.
Example
For a 50 kW run with a distance of 1,000 feet, using 240V delta: Transformer option
Step-up transformer (240V to 480V) and step-down transformer (480V to 240V) at the customer's panel. Assuming a transformer efficiency of 98%: Wire size: 4/0 THWN-2 copper Transformer cost: $5,000 (approx.) Wire cost: $1,200 (approx.) Total cost: $6,200
New service option
New service from the power company with a 480V transformer. Wire size: 2/0 THWN-2 copper New service cost: $10,000 (approx.) Wire cost: $600 (approx.) Total cost: $10,600In this example, the transformer option is approximately
$4,400 cheaper than installing a new service.
When to Consider Transformers
Transformers are generally more cost-effective when: The power run is long (over 500 feet) The power level is relatively high (over 50 kW) The existing service voltage is lower than the required voltage for the wind turbine The customer's panel has limited space for additional circuitsConsiderations Efficiency
Transformers have an efficiency rating that affects power loss. Choose transformers with high efficiency to minimize losses.
Safety
Transformers require proper grounding and protection to ensure safe operation.
Maintenance
Transformers need periodic inspection and maintenance to ensure optimal performance.*
Noise: Pad-mount transformers can generate some noise, especially during load changes. Consider the location of the transformers to minimize noise impact. Flag for review