MRO Magazine

Feature

Mission Critical – Emergency Power Upgrades


TELUS completes an integrated project to build a new standby generation plant at a mission critical network facility.

As one of Canada’s leading telecommunications companies, TELUS has a multitude of network buildings
located throughout Canada. Network buildings provide a number of key telecommunications services,
which include outside plant communications (telephone, data and television), mobility services, data centre services, web hosting, co-location facilities, etc. Network buildings are typically divided into areas, which contain telecommunications equipment (network spaces), building services (mechanical and electrical equipment) and office space for general corporate functions.

DC power plants, which consist of numerous strings of batteries, rectifiers, inverters and distribution equipment, and uninterruptible power supplies (UPS), provide power to network equipment. This helps ensure that any external, grid-related power interruptions do not interrupt telecommunications services.

While uninterruptible power can support network equipment for up to several hours, the stored energy in battery systems will eventually be depleted, and it is not feasible to support large building cooling systems (required to prevent network equipment from overheating) with battery backup. Standby
diesel generators are typically used to back up battery systems, building cooling systems and an entire facility’s electrical load, in the event of a prolonged utility power outage.

Replacing end-of-life standby generation can be a daunting task, especially when interruptions to critical network services cannot be tolerated. The challenges are further increased, when you undertake a project in a high-rise building, in a high-density urban environment and in a seismic zone. TELUS faced these challenges when it undertook a project to a build a new standby generation plant in a network building
in downtown Vancouver.

The project started with a feasibility study to review various concepts for replacing the existing standby generation plant, which consisted of five packaged generators (in prefabricated enclosures), installed on the building’s lower roof (Level 9). Given the limited space within the building, the options included installing new packaged generators on a higher roof (Level 13) or building a new floor on the higher roof, to house a new standby generation plant. The benefits, drawbacks and budgetary allowances for each option were outlined.

Given considerations for operability, reliability and maintainability, and ongoing neighbourhood development, building a new building floor and standby generation plant was selected. To accommodate future load growth for the site, an overall master plan was developed. Once the new generator
plant was constructed, the existing packaged generators would be removed, existing cooling towers would be replaced and a second generator penthouse would be constructed on the lower roof. TELUS reviewed budgetary constraints and developed a spend profile for the project that would align with a
phased construction approach. The first phase of the project involved constructing a new penthouse on Level 13 to house a 6MW standby diesel generator plant (a 4MW design load with N+1 redundancy).

Preplanning for the project began and H.H. Angus & Associates Ltd. was selected to provide electrical and mechanical engineering services for the project, to maintain continuity with the feasibility study. Since the project consisted of major electrical upgrades, along with mechanical infrastructure to support the new generating plant, H.H. Angus also assumed the role of the prime consultant and was responsible for co-ordinating the architectural and structural design of the new penthouse.

General space planning and concept design started with layouts for the new generating plant; a new medium voltage AC power room for distribution equipment used to interface with the new plant and to feed the building’s critical loads; and a new main fuel oil room, which supplemented existing fuel oil storage tanks with approximately 50,000L of storage.

While preliminary design work was underway, engineered specifications and drawings were prepared for an equipment pre-tender package. Generator suppliers were invited to submit proposals for the supply of an integrated equipment package. The equipment supply package included four 2MW, 12.47kV diesel generators (the fourth unit was bought in anticipation of the next phase of the project); approximately 25 bays of medium voltage switchgear, complete with automatic transfer and paralleling controls; diesel emissions reduction system (DERS) modules (used to catalyze emissions and reduce pollutants);
a 2MW resistive load bank and a 2.5MVA dry-type transformer for the load bank; and DC power distribution equipment to interface with the building’s 48V DC system, providing control power to switchgear controls. Multiple proposals were received and the equipment supply package was awarded
to Finning CAT.

With the equipment supply package awarded and equipment package in production, the design for the installation and construction of the new generator penthouse entered its final phase. A detailed set of drawings and specifications was prepared for all disciplines (architectural, electrical, mechanical
and structural). The new penthouse was designed to integrate with the existing 12-storey building, and special consideration was given to both the new infrastructure requirements and aesthetics of the existing downtown Vancouver neighbourhood. Intake and exhaust plenums were designed and co-ordinated with building structure, to ensure adequate airflow was provided for generator operation.

The exterior penthouse walls and roof were co-ordinated with plans for future building facade upgrades. The penthouse structure included innovative removable hatches to help facilitate the installation of equipment and allow for the future removal of generator sets. New service risers were created for medium voltage power cabling, low voltage cabling, control wiring, fuel oil piping and urea piping for the DERS modules. Diversified, redundant routes for new service risers were incorporated into the design, where possible, to improve reliability. The new fuel oil storage room was designed for connection to the site’s existing fuel storage tanks, for future reserve capacity. A new 480V power distribution system with
redundant 3000/4000 kVA, ANN/ANF, dry-type transformers was installed to provide ancillary power for the new generator plant and to facilitate future electrical load migration. Construction control drawings with site constraints, such as no onsite parking, building access requirements and available spaces for material laydown, were included to complete the design package. General contractors were invited to submit proposals for the project and after a detailed evaluation of submissions was completed, the project was awarded to PCL Constructors West Coast Inc.

Construction started following contract award, with the submission of shop drawings for the numerous trades that were involved on the project, procurement of materials, and the application for municipal permitting and road closures. A tower crane was erected on the building’s lower roof (Level 9) to transport materials from street level to Level 13. Once pre-construction activities were completed, the site had been prepped for the new build, structural steel was delivered to the site and framing for the new penthouse was started. As construction on-site was progressing, manufacturing of the pre-tendered equipment package was nearing completion.

Given the critical nature of the facility, new electrical equipment was required to undergo rigorous off-site testing before being shipped to the site. Initial testing of the medium voltage switchgear and controls was completed at the switchgear supplier’s factory and included detailed physical inspections, operational scenarios with logic simulation, dielectric testing and primary current injection testing for protective relays.

Once initial testing was completed, the medium voltage switchgear was shipped to the generator supplier’s testing facilities for complete integrated testing with the new diesel generators and an array of temporary infrastructure. Integrated factory testing focused on dynamic testing of the system as a whole and included paralleling, synchronization between units, load sharing, simulated failures and automatic transfer functionality. The overriding goal of integrated testing was to identify any major operational issues before the equipment was shipped to the site, thereby minimizing the risks associated with site testing. While off-site testing and construction of the penthouse were ongoing, the project team emphasized the importance in maintaining schedule on both fronts, such that the target date for equipment delivery to site, which required a major road shutdown, could be maintained.

At the onset of the project, booking a date for a road closure to facilitate the delivery of equipment to the site, which required the set-up of a 500-ton mobile crane, was a major project challenge. As the site was located on a major downtown street, shutdowns were limited to a few weeks each year, to avoid impact to other municipal road shutdowns and seasonal traffic requirements. Once a road closure and lift date were scheduled, it was important that both the equipment and the site were ready in time. Fortunately, a realistic schedule, with detailed input for the various team members, was created and implemented.

The equipment lift was completed over the course of a weekend in early November, with two days being required for setting up/demobilizing the 500-ton crane and one whole day being dedicated to lift the equipment into place. Given the planning and co-ordination efforts by the contractor, as well
as having the weather co-operate with minimal wind (despite non-stop rain), the equipment lift was a success. The equipment was set in place and the final stages of construction were completed.

New electrical and mechanical infrastructure was installed and thoroughly commissioned. The entire penthouse was tested under full design load (6MW) conditions, to ensure ventilation, fuel oil and electrical systems operated per design requirements. This process necessitated the installation of 4MW
of temporary load banks on-site, with the additional 2MW being supplied by the permanent load bank. Once commissioning and site testing were successfully completed and outstanding issues were addressed, the entire building load was transferred to the new distribution system, via a phased approach. Each phase involved a detailed method of procedure process for load transfers, followed by dynamic site testing, to ensure the system would operate as expected. Load transfers were successfully completed over the course of several weeks with the new generation plant supported by the entire building load.

Building a new generator penthouse on the top storey of a high-rise building, in order to replace critical electrical infrastructure, can seem like a formidable challenge. There are several key success factors that facility managers should undertake when considering a project of this nature. Following a detailed planning process, which starts with a feasibility study and design options, enables planning departments to develop appropriate budgets to complete infrastructure renewal.

Designating the right prime consultant (design lead) to oversee a multidisciplinary design process, helps ensure that new physical space is designed to serve the infrastructure that will be installed within. Developing a collaborative approach with major equipment suppliers and the installation contractor
can help identify schedule issues, lead-time requirements and progress expectations. As demonstrated by the innovative project completed by TELUS, a mission critical facility was able to construct a 6MW generation plant on the top of a highrise building, in downtown Vancouver, in just over one and a
half years. MRO

___________________________________________________
Philip Chow, P.Eng., P.E., was the lead electrical engineer on the project
and is a Senior Project Manager at H.H. Angus & Associates Ltd.
Philip specializes in electrical infrastructure projects and construction
in mission critical facilities and can be reached at philip.chow@hhangus.
com.

Peter Formosi, P.Eng., was the lead mechanical engineer on the project
and is a Senior Engineer at H.H. Angus & Associates Ltd. Peter specializes
in mechanical infrastructure projects and fuel oil systems and
can be reached at peter.formosi@hhangus.com.

Matthew Walker, P.Eng., was the project lead and is a Senior Project
Manager at TELUS Communications Inc. Matthew has significant experience
with infrastructure projects in mission critical facilities and
can be reached at matthew.walker1@telus.com.