A leading pet specialty retailer of pet food, supplies and services, Petco, opened a state-of-the-art 777,000 sq. ft. distribution facility in Reno, Nevada. Although it was designed to be energy efficient, there were clear power quality problems right away. The facility included a large amount of LED lighting. They also utilized a fleet of 100 battery-powered fork lifts to deliver goods between conveyors and loading docks. Dozens of variable frequency drives (VFDs) control the conveyors and other material handling equipment used within the facility. During peak times, when the forklift batteries were being charged, the VFDs began faulting out, bringing the flow of operations to a halt. The Petco facility could not run at 100% production when all the fork lift battery chargers and production conveyors were operating at the same time.
A two-step correction plan using power equipment from TCI was created. Step one included installing three-phase 5% line reactors in every battery charger sub system. 3% reactors were already installed in front of the VFDs. Single-phase reactors were recommended for each branch of the lighting panels. This brought the harmonic content down to a level in which most of the sub systems could operate on a continuous basis.
Step two brought the facility into IEEE Standard 519-2014 compliance. A 150 Amp Active Harmonic Filter was installed next to the Multiple Switch Board (MSB) to monitor the line for any harmonic contamination. The filter causes the injection of the appropriate amount of energy into the system and actively reduces the harmonic level to near 4%. This system successfully mitigated the high harmonic currents and allowed the charging of all mobile equipment while operating the entire conveyor system. However, as expected, the filter went into “At capacity” during the charging period because the overall corrective current was nearly 300 Amps. To complete the mitigation system and achieve optimal power quality, a 400 Amp corrective current filter was installed to address the entire facility.
Since the installation of these active harmonic filters, Petco has not experienced any downtime in production due to faulted VFDs since February 2018.