Streamlined Trunk-Bus Architecture Accelerates Solar Farm Installation

Introduction A Midwestern solar farm is seeing a significant boost in efficiency thanks to TE Connectivity’s (TE) Customizable Trunk Solution, saving more on resources spent for installing electrical connections, like time, and labor. The Challenge An extensive power generation company has launched the construction of a 140-megawatt solar farm in Midwestern areas of the U.S. Often, this solar farm faces various site condition challenges that create delays, resulting in a prevalent worker turnover. A renowned engineering, procurement, & construction company was contracted to construct the so…

Introduction

A Midwestern solar farm is seeing a significant boost in efficiency thanks to TE Connectivity’s (TE) Customizable Trunk Solution, saving more on resources spent for installing electrical connections, like time, and labor.

The Challenge

An extensive power generation company has launched the construction of a 140-megawatt solar farm in Midwestern areas of the U.S. Often, this solar farm faces various site condition challenges that create delays, resulting in a prevalent worker turnover. A renowned engineering, procurement, & construction company was contracted to construct the solar farm.  This on-site installation has involved at least 250 on-site workers and took more than one year. The site is located on a former rice field in rural Arkansas in an area susceptible to routine thunder, flooding, seasonal tornadoes, excessive heat waves, and lightning storms. The vulnerability of the site, coupled with the recent COVID-19 pandemic, resulted in additional delays that threatened to postpone the solar farm delivery by several months. According to the EPC’s Project Manager, “such challenging sites escalate labor costs”, an additional blow to the new wind farm. To overcome the mentioned challenges, the EPC decided to rely on TE’s CTS system - Solar Customizable Trunk Solution. It utilizes a trunk-bus with a centralized architectural design to provide a more significant and less complicated wiring architecture, unlike the common traditional approaches that rely on hundreds or thousands of individual combiner box connections.

The Solution

The CTS system simplifies installation requirements thanks to the use of patent-pending Gel Solar Insulation-Piercing Connectors (IPC). These IPCs have a trustworthy record in generating traditional power and they are now found in solar power firms.  IPCs have miniscule piercing blades that penetrate a cable’s insulating jacket and establish an electrical connection with the conductor underneath the insulation. The electrical connection neither requires a labor-intensive cutback nor stripping by electricians. Instead, the technicians will only need an impact wrench or a socket to complete the work. TE Connectivity provides IPC with a protective box enclosure. The gel box is a clamshell enclosure filled with TE’s Raychem Powergel sealant. When using the system, most on-site electricians report that there’s always a need to install at least two IPCs, with each installation lasting two minutes. Installation includes cleaning cables, testing them for continuity, hand tightening the connectors, testing their continuity, then cutting the end strings to length. Installing the connectors is more simplified when using a shear bolt head. This head separates automatically after achieving an engineered torque. After that, the connector blades will simultaneously penetrate a cable insulation and then reach the conductor strands. It only takes 20 seconds to install the shear bolt portions completely. In turn, this speed reduces technician labor time by 40%+ compared to traditional approaches. “This installation speed is incredible, and the traditional approaches may require twenty minutes for negative and positive ends,” says an on-site Project Manager.

The Outcome

The outcome has shown that TE Connectivity’s solution could significantly reduce the labor and time needed to set up the Arkansas solar farm’s electrical portions. An on-site installer noted, “we can install up to ten IPCs and terminate a Trunk Bus Disconnect (TBD) to close a circuit in less than 20 minutes, so it’s been an extreme time saver.” An additional advantage of this CTS system lies in its ability to reduce the number of connections. This characteristic minimizes the possibility of current leakages and the voltage drops that can occur across a solar farm’s perimeters. For this specific solar project, the CTS construction is anticipated to aid the farm to meet the targeted 1.5% max voltage drop. This drop is expected to be for the farm's DC-collector network. "Clear communication, precise documentation, and thorough training of the installation team has helped us achieve a "smooth" installation and resulted in no complaints throughout the solar project." reported the on-site Project Manager. During prevalent solar project delays, this farm's EPC staff had estimated that this installation process was likely to be 3 months behind plan. Thankfully, CTS delivered an opportunity to save time, and now, the team of experts expects to complete this installation only one or two weeks past the delivery date.