In recent years, the demand for solar energy has grown as a green alternative to traditional fossil fuel-based power generation, and the trend of solar power generation devices has been moving towards systems that have both a larger footprint and greater production capacity.
However, as the capacity and complexity of solar farms continue to grow, the costs associated with their installation, operation and maintenance are also increasing. Unless the system is designed correctly, as the system size increases, small voltage losses will increase. TE Connectivity’s (TE) Solar Customizable Trunk Solution (CTS) system relies on a centralized trunk bus architecture (described below). This design provides an effective alternative to traditional methods, which rely on hundreds of individual combiner box connections and more complex overall wiring schemes.
TE’s Solar CTS eliminates the combiner box by laying a pair of aluminum cables on the ground, and can flexibly connect TE’s wiring harness with our patented Gel Solar Insulation Piercing connector (GS-IPC) along any length of the wire. From an installation point of view, this requires fewer cables and fewer connection points to be built on site.
The CTS system provides immediate savings for system owners and operators in terms of reducing wire and cable costs, reducing installation time and speeding up system startup (a savings of 25-40% in these categories). By systematically reducing voltage loss (thus protecting production capacity) and reducing the workload of long-term maintenance and troubleshooting, it can also continue to save money during the entire life cycle of the solar farm.
By simplifying on-site troubleshooting and maintenance, the CTS design also improves the overall system reliability and efficiency of large-scale solar farm operators. Although the system benefits from standardized and modular design concepts, it can also be customized to address site-specific conditions and engineering considerations. An important aspect of this product is that TE works closely with customers to provide complete engineering support. Some of these services include voltage drop calculations, effective system layout, balanced inverter loads, and training of on-site installers.
In any traditional solar power system, every connection point-no matter how well designed or installed correctly-will produce some smaller resistance (and therefore leak current and voltage drops across the system). As the scale of the system expands, this combined effect of current leakage and voltage drop will also increase, thereby damaging the production and financial goals of the entire commercial-scale solar power station.
In contrast, the new simplified trunk bus architecture described here improves the efficiency of the DC grid by deploying larger trunk cables with fewer connections, thereby providing a lower voltage drop across the entire system.
Gel solar insulation piercing connector (GS-IPC). The gel-like solar insulation piercing connector (GS-IPC) connects a string of photovoltaic panels to the relay bus. The trunk bus is a large conductor that carries a high level of current (up to 500 kcmil) between the low-voltage DC network and the system DC/AC inverter.
GS-IPC uses insulation piercing technology. A small piercing blade can penetrate the insulation sleeve on the cable and establish an electrical connection with the conductor under the insulation. During installation, one side of the connector “bites” the large cable, and the other side is the drop cable. This eliminates the need for on-site technicians to perform time-consuming and laborious insulation reduction or stripping work. The novel GS-IPC connector only requires a socket or an impact wrench with a hexagonal socket, and each connection can be installed within two minutes (this is reported by early adopters of the novel CTS system) . Since the shear bolt head is used, the installation is further simplified. Once the pre-designed torque is obtained, the shear bolt head will be cut off, and the blade of the connector penetrates the cable insulation layer and reaches the conductor line at the same time. Damage them. GS-IPC components can be used for cable sizes from #10 AWG to 500 Kcmil.
At the same time, in order to protect these connections from UV rays and weather conditions, the GS-IPC connection also includes another important design element-the protective plastic box housing, which is installed on each trunk/bus network connection. After the connector is properly installed, the field technician will place and close the lid with TE’s Raychem Powergel sealant. This sealant will drain all moisture in the connection during installation and eliminate the ingress of future moisture during the life of the connection. The shell of the gel box provides complete environmental protection and flame retardancy by reducing current leakage, resisting ultraviolet rays and sunlight.
Overall, the GS-IPC modules used in the TE Solar CTS system meet the strict UL requirements for photovoltaic systems. The GS-IPC connector has been successfully tested in accordance with UL 486A-486B, CSA C22.2 No. 65-03 and the applicable UL6703 test listed in Underwriters Laboratories Inc. file number E13288.
Solar fuse bundle (SFH). SFH is an assembly system that includes in-line overmolded higher rated fuses, taps, whips and wire jumpers, which can be configured to provide a prefabricated fuse wire harness solution that complies with UL9703. In a traditional solar farm array, the fuse is not on the wire harness. Instead, they are usually located on each combiner box. Using this new SFH method, the fuse is embedded in the wiring harness. This provides multiple benefits-it aggregates multiple strings, reduces the total number of combiner boxes required, reduces material and labor costs, simplifies installation, and increases continuity related to long-term system operation, maintenance, and troubleshooting save.
Relay disconnect box. The trunk disconnect box used in the TE Solar CTS system provides load disconnection, surge protection and negative switching functions, which can protect the system from surges before the inverter is connected, and provide operators with additional connections as needed And disconnect the flexibility of the system. . Their location is of strategic significance to minimize cable connections (and does not affect the voltage drop of the system).
These isolation boxes are made of fiberglass or steel, with surge and general grounding functions, and can provide load breaking up to 400A. They use shear bolt connectors for quick and easy installation and meet UL’s requirements for thermal cycling, humidity and electrical cycling.
These trunk disconnect boxes use a load disconnect switch, which has become a 1500V switch from scratch. In contrast, other solutions on the market usually use an isolating switch constructed from a 1000-V chassis, which has been upgraded to handle 1500V. This can lead to high heat generation in the isolation box.
To increase reliability, these relay disconnect boxes use larger load disconnect switches and larger enclosures (30″ x 24″ x 10″) to improve heat dissipation. Likewise, these disconnect boxes can accommodate larger The bending radius is used for cables with sizes from 500 AWG to 1250 kcmil.
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