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How to Deploy Wireless Communications for the Solar Industry

Wireless distributed intelligence networks for utility and commercial solar power facilities can lower installation and infrastructure costs while providing secure, reliable data communication.

As investments in manufacturing for the solar power generation industry continue to increase, issuers are seeking a secure, reliable communication network for critical-data transmission at the best cost/performance ratio. Communication options range from fiber optic cable to standards-based and proprietary protocol wireless technologies. A range of distributed intelligence communication networks can support all types of utility and commercial scale solar power generation models.

This article explains how deploying wireless distributed intelligence networks can lower installation and infrastructure costs while also providing secure data communications and reliable, robust performance.

We also examine the advantages of using wireless distributed intelligence communications systems for the utility and commercial scale solar power industry, and explain how to deploy a reliable, secure data communications network throughout the plant.

Ensure Reliability and Security
Utility-scale and commercial-scale solar power generation are on the rise, so operators need new ways to maximize their investment in communication networks while ensuring reliable, secure data transmission. Options include data radios, fiber-optic cable, cell phones and satellite modems.

The same wireless distributed intelligence networks used in many utility applications, such as distribution automation, are available to solar power generation facilities.

With solar power generation, systems can benefit from the cost savings of wireless versus fiber-optic cable. Wireless technologies can support all types of solar power generation models, from the solar troughs, dishes, tracking photovoltaic, fixed photovoltaic, heliostats, etc. These wireless technologies deliver valuable management and operations information to the user's desktop.

Wireless distributed intelligence is appropriate when:

• The system owner wants to control communications.
• Budgets require efficient communications investment.
• Cell phone coverage is inconsistent or nonexistent.
• Communication security is a priority.

The need to identify ways to lower infrastructure costs, improve time-to-market and increase performance is no longer a wish, but a requirement.

Comparison of Communication Network Options
As the solar power market continues to make strides, operations and maintenance personnel need economical ways to manage their systems. To do this most efficiently, some sort of communication system is required.

Today, solar power generation plants have economical systems that ensure reliable, secure data transmission from remote locations. Wireless distributed intelligence networks need to be maintained easily, with the ability to handle the amount of data transmission required. Many operations and maintenance providers are beginning to discover the options:

Wireless Data Radios. The top industrially hardened class of proprietary protocol wireless radios systems are easy to install, require minimal labour, and don't require any trenching or expensive equipment. In addition, users can obtain real-time data fast. Users can be operational quickly and don't have to wait until some sort of network topology is complete.

Although these radios are reliable, often they're more expensive than standards-based radios because they provide the range, throughput options and reliability found only in this class offering.

When used in a distributed intelligence network, these solutions are ideal for solar monitoring and tracking, especially when solar troughs are located in a remote location. This type of network also will give the operator more control with the ability to isolate and focus on key points in the network.

A somewhat inexpensive, standards-based wireless solution, Zigbee offers a self-healing mesh network. These products have a direct sequence protocol that is more susceptible to interference, especially when compared with proprietary protocol systems.

The range is short compared to others, and as users add repeaters to lengthen the range or coverage, the throughput degrades quickly — and the "perceived" low cost goes up.

At 230 Kbps, the throughput without repeaters is acceptable in many applications. However, to achieve the self-healing networks, repeaters are required. As stated previously, as repeaters are added, throughput decreases and costs increase.

Copper, fiber and an Ethernet cable are some of the options available as wired solutions. Each of these types of cable will have limitations in how far the signal can be sent before you encounter line loss. In addition, wired solutions typically require more money and more time to install.

However, if implemented correctly, wired solutions provide the best in terms of security and reliability — though not necessarily appreciably better when return on investment (ROI) is a concern. The main issues operators face with wire are the cost of materials and installation. Time to install also is an issue when compared with wireless data radios.

Cell Phone/Satellite.
Cell phone and satellite technologies have many similar attributes. Both are public systems and, therefore, not controlled by the plant owner.

Carrier-based systems such as these include monthly fees that add to the overall cost of ownership, making them even more costly over time. Notoriously, cell phone-based systems don't have a history for being backwards compatible.

Replacing old technology with new technology can be costly. Sometimes these systems can reach extreme or remote locations where it isn't feasible to lay fiber or even deploy a full wireless communications network. This especially is true in the case of satellite systems.

Distributed Intelligence in a Solar Project
In 2008, leaders at a concentrated solar power field in California were looking into ways to optimize its communications network. They began comparing costs for wired and wireless solutions that had reputations for effectively conducting flow-monitoring and tracking applications.

At first, they weren't sure a wireless system would be effective. They were also concerned that the antennas from the radios could potentially shadow the troughs and negatively affect solar power generation. They allowed a wireless 900 MHz data-radio provider to do an on-site test to prove that wireless is easy-to-install, reliable and flexible.

At this particular field, a total of six radios were installed — each at a remote location — along with a master radio at a central location.

Because of the distributed set-up of the network, the operations and maintenance office was able to monitor each individual site as needed. This example of distributed intelligence allowed for optimal monitoring because it could isolate the monitoring at each specific point if needed.

The radios proved to be reliable over the course of several months in varying environmental conditions. This was achieved in three different radio system configurations. The concern regarding the antennas was eliminated, because the radios didn't shadow the troughs. In addition, the installation was easy and inexpensive.

Wireless Applications Expected to Grow
The advances of wireless technology in the solar power market on both an industrial and commercial scale have increased with the deployment of distributed intelligence networks. The costs, reliability and reporting are driving operators to consider alternatives to wired solutions.

Wireless data radio technologies provide a long-range, reliable and affordable solution to providers. Distributed intelligence is a viable solution for monitoring and tracking applications in the solar industry.

A wireless system potentially can save a company millions of dollars in installation fees, and the technologies have been proven in the field in many industries. When ROI is a key in determining the best communications solution, the benefits of distributed intelligence with top-class data radios should considered in the decision process.

By Bret Dianich, Business Development Executive, FreeWave Technologies, Inc.

FreeWave Technologies, Inc.


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