Connector Innovations for Renewable and Alternative Energy Applications
By Ted Worroll, ITT Interconnect Solutions

As renewable and alternative energy become more prominent in today’s society, all elements of the energy system must keep pace with advances in system design, even down to the components in the interconnect system. Enhancements in connector technology make this possible. Robust contact materials, contact design, changes to minimize electrical loss, and enhancements to seal the connector against environmental elements have made them fully dependable in photovoltaic, wind, and nuclear power applications.

High Efficiency, Low Loss
Renewable and alternative energy systems—including wind, photovoltaic, and nuclear power—are dependent upon the amperage generated throughout the system, and interconnect technology plays a critical role. In wind power, for example, connectors and cables are employed to link the generator to the motor and the motor to the fuel cell. They also find uses within the control monitoring equipment. Photovoltaic energy systems employ interconnects to connect the solar panel modules, inverters, and control system. Any loss in either system is detrimental, as it takes away from the amperage generated, and thus, from the efficiency of the renewable energy system. Consequently, highly efficient interconnect systems are paramount. Maximizing the transfer of energy is largely dependent upon the connector’s materials and the construction of the connector contacts.

Materials Selection
An efficient connection between all devices in the energy system ensures maximum absorption of power and minimal loss. Materials that lend themselves to being good conductors frequently start with specific copper alloys. Tellurium is often used in place of standard copper, brass, and even stainless steel constructions. For example, when an inverter takes electricity generated by a photovoltaic module and turns it into useable AC power, some of that energy can be deferred into a battery for storage. While copper contacts are occasionally used, tellurium is the most effective.

Along with low-loss materials, some alternative energy applications require the use of materials that do not emit gases. In nuclear power applications, for example, inserts, o-rings, gaskets, and other components are often made from neoprene, which can become brittle when exposed to high temperatures and high radiation, causing a breakdown in the continuity of signals, and thus device failure. Because of this, connector elastomers for these applications must be comprised of a high temperature, radiation-resistant material that does not degrade when exposed to vapors found in the containment areas, such as nuclear grade silicone. Furthermore, the material selected must guard against unforeseen situations, such as a pipe rupturing in the containment area and emitting water and boron, since these chemicals can erode aluminum materials and produce an explosive hydrogen gas. Nuclear-grade silicone materials and nuclear grade A stainless steel shells won’t degrade under these conditions, and therefore are the desired materials in nuclear energy applications. Additionally, plating the contact with a heavier metal (such as stainless steel), than is used with standard applications will also increase the connector’s effective lifespan.

Contact Construction
Material choices are critical when maximizing power transmission, as well as insulating between the grounds or conductors in multiple lines of power, with dielectric inserts to shield currents from each other. Connector contact construction is also paramount in terms of maximum transfer of power in energy applications. Typical male and female contacts are suitable for low frequency and low signal applications, but for high-power use, designs with as much metal-to-metal interface as possible transfer the highest amount of energy. Ideally, male-to-female contacts will exhibit a full 360 degrees of metal-to-metal contact. Full-metal designs, with shielding for each pin and within the connector housing maintain signal integrity, and therefore allow maximum power transmission.

In photovoltaic, wind, and nuclear power applications, contact systems must also be touch-proof. For example, if a worker separates the connection in a wind power system for repair purposes while the wind generator is still spinning, the connection is still “live,” meaning it is potentially producing enough energy and amperage to kill someone if the connector contact is touched. A touch-proof construction is often accomplished by placing a plastic plunger over the male pins, preventing the potential for human shock by allowing the female contacts to come in contact with only the metal male pin. Making the interface on the active side of the connector touch-proof eliminates the opportunity for an operator to be shocked if they come in contact with the connector.

Sealing and Certifications for Energy Systems
Renewable and alternative energy applications require connectors that meet stringent sealing and certification standards. Because these connectors are constantly used in the field, they must be properly sealed so they don’t gradually build up oxidation. If oxidation occurs, the contact resistance will increase over time, negatively impacting the effectiveness of the connector, and thus the amperage generated through the system. Most connectors are sealed to at least IP67 or IP68 specifications. Designing connectors with an extremely low contact resistance further ensures minimal loss and maximum energy transfer.

Connectors used in nuclear power containment area applications are required to meet even more stringent specifications, including IEEE certifications, such as IEEE323-1974, IEEE383-1974, and IEEE344-1975. These certifications specify that a connector is capable of withstanding radiation exposure in excess of 150 Megarads, simulating a 40-year aging test.

Materials and contact construction play a pivotal role in a connector’s suitability for renewable energy applications, and ultimately impact the proper performance of the overall system. Tellurium, stainless steel, robust contact construction, and touch-proof systems are just a few of the design considerations, and working with one of the few connector suppliers capable of designing products in accordance with nuclear energy certifications is also key to creating the products that will help fuel our future.

Ted Worroll is a product manager at ITT Interconnect Solutions and has been with the company for 23 years. Prior to joining ITT, Ted spent nine years with LFE Corporation and six years with WALSCO. Ted can be reached at ted.worroll@itt.com or 860.945.8274.