aep texas project edison award winner

1 AEP’s Energized Reconductior Project for the Lower Rio Grande Valley

Edison Award Entry I April 2016



OVERVIEW The Energized Reconductor Project of the Lower Rio Grande Valley (LRGV) is a landmark accomplishment for American Electric Power (AEP) and the utility industry. The 240 mile project capitalized on multiple innovative technologies from across the industry, allowing AEP to provide an immediate solution to the problem of reliable electricity while addressing future load growth.

The LRGV is served by two 345-kV transmission lines that originate from Corpus Christi, 120 miles to the north, and account for the bulk of the electricity carried into the LRGV. The lines are in a vulnerable position due to the LRGV’s dependency on them to supply the majority of the power to South Texas, as well as their proximity to the Texas Gulf Coast exposing them to corrosive salt spray and making them susceptible to storm outages.

In February 2011 South Texas experienced record winter temperatures which dropped as low as 20 degrees Fahrenheit. For a region accustomed to average February temperatures in the mid 60’s, these temperatures were crippling. Panicked residents flooded the stores in search of portable heaters. This immediate increase in demand for electricity coupled with downed generation due to prescheduled maintenance resulted in rolling blackouts throughout the region due to the limitations of the transmission system.



CHALLENGES

Summer highs in the LRGV routinely hit triple digits. This, coupled with a 30% population growth from 2000-2010, resulted in AEP’s peak electric demand increasing from 1000 MW in the summer of 2000 to a summer record peak demand of 2220 MW in 2010. While an increase in load over a decade is to be expected, the 514 MW jump from the previous summer during the 2011 winter storm (2220 MW to 2734 MW) was outside all modeled projections. Furthermore, due to continued growth, the projected 2016 summer peak load is expected to reach 2800 MW with a forecasted summer 2020 peak load of over 3000 MW.

An immediate plan was needed to supply relief to the circuits most affected by the short term seasonal spikes. However, this plan also had to offer a long term solution to address the load increases for 2016, 2020 and beyond. AEP, as well as the Electric Reliability Council of Texas (ERCOT), needed a solution that could meet the pressing demands and provide reliability while safely maintaining an aggressive schedule. ERCOT was presented with a number of traditional cold construction options for increasing capacity on these circuits, running the gamut of temporary upgrades to complete overhauls. As AEP looked into permitting, right of way (ROW) acquisition and various customer disruptions, it became apparent that these variables had a very real chance of interrupting their customer’s service or adding unforeseen costs to the project. However, the biggest area of concern for AEP was that ERCOT could only grant outages clearances in the spring and summer months, if at all, and the lines would be required to be restored to full service whenever system anomalies warranted.

AEP chose the energized solution because it allowed them to use the existing right of ways and structures, limiting property disruptions and reducing the overall cost to their customer.



AN INNOVATIVE SOLUTION Taking the list of challenges into account, it was apparent to AEP that a traditional construction solution would only add additional delays to an already time sensitive project and therefore could not be counted on as a viable option to meet the 2016 completion schedule.

AEP approached Quanta Energized Services, an entity of Quanta Services, to discuss their live-line planning and construction expertise. While smaller energized projects had been successfully completed in the past, an energized reconductor project of this size and length (240 mi.) had never been attempted. To ensure that construction of the project was completed by the mandated 2016 in service date, AEP concluded that no new structures or right-of-away could be purchased. Under this plan a lightweight, high capacity conductor was needed and cable manufacturer CTC Global, with their revolutionary ACCC Composite Core Conductor, were brought onboard the project team. AEP, confident that the issues associated with traditional transmission line construction had been averted. A joint work plan with Quanta Energized Services technical advisors to reconductor the entire 240 miles while keeping the lines in-service and energized. In early spring 2011, AEP’s plan to perform the energized reconductor of the existing 345-kV transmission lines was approved by the regional planning group at ERCOT.

Above: Quanta Energized Services Linemaster Robotic Arm chosen for AEP LRGV Reconductor.

Below: Aluminum Conductor Composite Core (ACCC) a lighter alternative to conventional conductor, reduces sag while doubling the capacity. This project was the longest installation of advanced conductor in North America.



STATE-OF-THE-ART TECHNOLOGIES Through the innovative partnerships with Quanta and CTC Global, AEP was able to capitalize on several 21st century technologies that not only accelerated the work schedule to ensure that the required in service date for the upgraded line was achieved but also benefit the environment and increase the level of safety for all involved. The two technological advances that made this project possible were:

Aluminum Conductor Composite Core (ACCC)

• The use of Aluminum Conductor Composite Core (ACCC) to replace the existing conductor. While the same diameter as the original conductor, ACCC, due to the reduced size composite core, is comprised of 28% more aluminum.

• The extra aluminum and higher temperature rating allows for twice the capacity of conventional conductor. The composite core reduces thermal sag. Replacing the old conductor with one of the same diameter and weight but more capacity meant that AEP could replace the old conductor without widening clearances or causing tower modifications and rebuilds.

• Due to the added aluminum, line losses were reduced by up to 40%, equaling a savings of over $30 million dollars in the first year alone.

• The lower emission from the CO2 reductions in the first year is equivalent to removing 34,000 cars from the road.

• Also of great importance, due to the location of the job, the ACCC is more resistant to corrosion and has the ability to handle future increases in load.

Energized Barehand Work Methods & Linemaster Robotic Arm

• The Energized Barehand work methods and proprietary LineMaster Robotic Arm made it possible for all 240 miles of 345kV conductor to be removed and replaced without interrupting the flow of electricity.

• Attached to a boom on a ground-based vehicle, the LineMaster Robotic Arm safely moves and securely holds energized power lines while the conductors, insulators and structures are maintained, replaced or rebuilt.

• The LineMaster Robotic Arm allowed the construction team to safely work without any outages on the project.

• Its all weather capabilities allowed for it to remain in place during poor weather while the crew found shelter and then continue work once the weather had passed.

• In addition to the robotic arm, barehand work methods and proprietary energized reconductoring procedures were developed by a team which collectively has more than 400 years of energized work experience, starting with the first-ever energized reconductor project in 1990.

• These methods, tools and equipment have been and continue to be tested and improved in the field and at the world renown STRI lab in Sweden.



PROJECT EXECUTION Once AEP identified the technology needed to complete this project and received approval from ERCOT to proceed, they went about coordinating the various complexities and components related to a project of this size. Constructing the project safely while not sacrificing the reliable power AEP’s customers expect on a daily basis were key drivers. Due to the vulnerability of the system, the key areas that needed to be upgraded were identified and prioritized. The difficulty of this task was multiplied by the fact that a segment of conductor needing to be upgraded often times was not connected to a substation that needed to be upgraded first. AEP closely managed all of these variables to ensure that there were no delays, work stoppages, or power outages.

A year before the first lineman hit the right-of-way, AEP and the Quanta Energized Services technical advisors went about developing detailed, project-specific work procedures with calculated man-hours, sequencing, schedules and anticipated resources.

The project called for an aggressive schedule to ensure that the line would be upgraded by the required date. The project was divided into five segments between the substations. Doing so resulted in several strategic, as well as, financial benefits:

• It reduced the risk on the entire system serving the LRGV;

• It prioritized the line sections between the substations, so that the completed areas could immediately reap the benefits of the system upgrade;

• It created five smaller projects, which increased the efficiency of scheduling materials, equipment and crews, as well as minimizing the project costs.

This is a temporary D Phase structure that has been installed inside of a three pole angle, allowing the outside phase to be transferred. This creates an open position on the existing pole to pull the new wire in. When the new wire is in, loads are transferred to deengerize another phase and pull another wire.

An energized reconductor of this size required careful planning. Work procedures for each task had to be developed. A group of technical advisors collaborated together to produce these procedures. As the project progressed, lessons were learned and these procedures were further refined and revised.

The barehand work method was instrumental to the work that was performed on the energized conductors. When working barehand, the lineman wear conductive suits and are bonded to the conductor, putting them at the same potential as the energized conductor allowing them to physically touch and work on the energized conductor and equipment. To support conductors while unclipping or clipping, the LineMaster Single Point Lifter robotic arm was used. This tool provided safe, secure and controlled support of the energized conductors.

In order to replace conductors in an energized state, a temporary support for a phase conductor needed to be established. This was done by installing temporary structures along the edge of the right of way next to the existing line. Since the temporary structures were installed within the ROW, no additional land or the timely permits associated with land acquisition were required.



The new conductor was then installed in its permanent position, clipped in and sagged. Electrical load from another phase was transferred to this new conductor and the old conductor was de-energized. The old conductor was then reconductored. This was repeated, until all the conductors were replaced, without any interruption to the electrical supply. This was performed section by section, on average 20 to 30 miles. This plan allowed for the reuse of existing structures, therefore minimizing the impact on landowners and negating any of the timely permits associated with land acquisition and construction.

Other realized cost savings during construction were the energized crews’ ability to perform out of the scope upgrades and maintenance, such as replacing damaged V-string insulators and the upgrade of existing shield wire with OPGW fiber. This type of work often requires months of planning to get the necessary outages, which can be cancelled at any time. This is one of the factors that led ERCOT to be able to take back every scheduled outage because construction and repairs were made while the line remained energized. The state-of-the-art and proprietary technology used on the energized reconductoring, led to ahead of schedule completion of the project, despite record-setting inclement weather.

Among the unique aspects of these one-of-a-kind work procedures was the ability to adapt to job irregularities. A necessary adaptation that occurred early in the project was related to the bundled conductor, which sat in a vertical configuration rather than the tradition horizontal configuration. To most efficiently tackle this issue the team needed to tailor both the equipment and the procedures to accommodate the vertical configuration. This first test proved to be a calling card for the entire project as procedures were continually updated to make the project safer and more efficient.

While numerous factors played an important part in the success of this project, from state of the art equipment, to extensive training, none were as important as the detailed work procedures. The work procedures, developed by the technical advisors, were developed specifically for each part of this project. Making the scope even more unique, was the fact that it was under continuous evolution. Methods of success and failure from the field, were used to further refine these

procedures. As work procedures were refined and the crews became experienced in these procedures and work methods the result was a gradual to substantial improvement in productivity, allowing the project to be finished eight months ahead of schedule and millions of dollars under budget.

The suit worn by barehand linemen consists of a hooded jacket, bib style pants, socks, and gloves. The suit is made of 75% Nomex and 25% stainless-steel fibers. The Nomex content of the suit qualifies as the outer fire-retardant clothing layer. The steel mesh woven into the suit serves as a Faraday Cage, shielding the lineman from the electric field. While wearing the barehand suit, the electric charge flows around the outside of the suit (the charged cage) and not through the lineman's body (the interior of the charged cage). With the metallic mesh clothing bonded to the conductor, the lineman can work inside the electrical field.

BAREHAND SUIT



SUBSTATION CHALLENGES As construction continued on the two 345 kV lines, the AEP project management team turned their attention to the five substations that tied into the lines. With the upgraded reconductor nearly doubling the electric capacity of the two 345 kV lines, AEP needed to upgrade the substations as they had not been built for the higher capacity. AEP’s concerns centered on the continuous current, as well as the fault current. This meant that additional bus supports needed to be added and everything that carried current had to be upgraded and replaced. Unlike the transmission line, an upgrade to the substations would require outage clearances from ERCOT to take the power out while working in the substation. Raising the level of complexity was the issue that for every outage AEP took on an already strained system, they would also be competing with other utilities and generators for these outage clearances.

The traditional timeframe to upgrade a substation is six to eight months, however, with the new conductor being installed every day and a lack of outage clearances available from ERCOT, AEP was given a shortened window to complete each substation. In addition to the shortened construction timeline, the vulnerability of the system dictated that ERCOT attach a restoration time on every outage clearance given. The mandated restoration time was normally shorter than the ERCOT approved outage clearance time and dictated how AEP could do the work on each substation during the outage clearance. This meant that instead of a complete demolition of the substation, AEP had to approach each substation work plan in a unique way, so that they could return the clearance if needed. In order to return the clearance by the ERCOT mandated restoration time a substation had to be rebuilt and upgraded one piece at a time. An example of this unique request is the construction of the control houses. As the breakers and conductor were changed out in the substation, the control cables were moved to the new control house until the original control house was empty and could be demolished. AEP, while working around the energized construction portion of the project, was able to safely upgrade each of the five substations in the allotted timeframe, without jeopardizing the grid and subsequently electric power to their customers in the LRGV.

COST SAVINGS ANALYSIS The inability to get outage clearances and the lengthy process of acquiring right of way pushed AEP toward the energized reconductor option. Another cost issue that is often overlooked in the overall construction budget is the ability to source generation to supplement the transmission lines that have been taken out of service. In areas where ample amounts of generation are not prevalent, less efficient generation sources must be used. This results in costly expenditures to the utility and their customers. By working in an energized state, alternative generation sources were not needed. Based on local generation costs, the combined savings for 2014 and 2015 was approximately $43,377,129.



AEP Simulation Lab The idea to reconductor the line in 20-25 mile segments, one phase at a time was a deviation from the conventional method of reconductoring all three phases at once, but necessary when completing a project in an energized state, while using the Linemaster Robotic Arm ™.

This unconventional way of reconductoring brought about questions that had to be answered. For example, when do you replace the relay settings for the reconductored line? Also, would the inrush current trip the line if the single phase breakers were utilized to move load on a phase in the 20-25 mile segment?

To answer these questions, simulations were run and studied in AEP Transmission’s Gahanna, Ohio simulation lab. These unique lab simulations led AEP to replace the relay settings before the

Pictured Yiyan “Spark” Xue, principal engineer over RTDS testing in AEP’s Gahanna, Ohio simulation lab.

line was reconductored. As well as determine that the relay settings would not trip the line during a single phase breaker operation.

AEP’s simulation lab minimized the risk on the project while avoiding delays and costs associated with conventional field test.



AEP completed the longest energized reconductor project eight months ahead of schedule and significantly under budget. The upgrade to the 345 kV ACCC conductor will allow for future clean energy generation to power the Lower Rio Grande Valley for the next several decades.

CONCLUSION The Future of Transmission Construction

This project not only strengthened the transmission system in the Lower Rio Grande Valley, it demonstrated that with collaboration and careful planning long distances can efficiently and safely be reconductored in an energized state. In an outage-constrained industry with heavy workloads and condensed time frames, this project demonstrates the industry has a viable option.

In South Texas with the completion of the 240 mile Energized Reconductor Project, AEP has ensured numerous communities in the LRGV that their need for reliable power today, tomorrow and well into the future will be met. Lights will stay on, homes will be cooled and heated, schools will stay in session and hospitals will continue to save people. AEP has shown that with the use of innovative technology and the lessons learned from the project they are prepared and more than ready to tackle all future issues in the LRGV.

During the course of the project AEP hosted nearly 20 utilities, including several international utilities, providing field tours and detailed classroom analysis. Throughout every visit, senior management from AEP was onsite to discuss and answer questions about project specifics. In doing so AEP ensured that the foundation built from the world’s longest energized project will continue to benefit future utility customers around the globe.



• Voltages up to 345kV

• Supports up to 2,250lbs per phase

• Vertical and horizontal applications

LINEMASTER ROBOTIC ARM ™ Quanta Energized Services’ Linemaster ™ Robotic Arm and Single Point Lifter create a safer and more efficient work environment for powerline construction, maintenance or upgrades. The LineMaster Robotic Arms provide temporary secure conductor support to existing conductors, while they remain in service.

SINGLE PICK THREE PHASE

THE PROCESS • The LineMaster Robotic Arm ™ operates by hydraulic actuators and attaches to conventional crane or boom trucks.

• When moved into position it captures the conductors, and can be operated to provide safe working clearances.

• The conductors are secured in wire holders on station class all weather insulators

• .An aging or damaged structure is removed and new structure is put in its place.

• Electricity continues to flow and the LineMaster Robotic Arm ™ is moved back into position so the conductor can be connected to the new structure.

• Voltages up to 765kV

• Supports up to 10,000lbs.

• Vertical and horizontal applications

aep texas project edison award winner

Environment