A large international food company has extensive bakery operations in the Southern USA for production of baked goods on multiple lines and is a continuous operation process.
The plant is located in a mixed industrial / residential district and is supplied by the local electrical utility at medium voltage (13.2kV). The plant has several transformers with 480V output which supply production equipment.
Unfortunately the plant experienced numerous unplanned production stoppages due to voltage sags. As many of these voltage sags were weather related, the electrical utility was unable to provide any simple solution but did suggest that the Customer should investigate the use of Voltage Sag correction equipment.
The bakery has a number of dedicated product lines where uncooked baked goods are placed on long conveyor belt systems which move the products through high temperature gas fired ovens, each of which can be several hundred feet in length. If a voltage sag occurs this can cause the variable speed drives which control the conveyor belts to trip, the belt stops but the oven is still hot. Typically the baked goods are burned and spoiled, so must be discarded but, in addition, Federal Food Administration rules require that all products be removed from any affected production line and scrapped, the system then needs to be cleaned and sterilized before production can resume. In addition to the lost value of the spoiled/scrapped products it can take several hours of work before normal production can be restored.
Following detailed analysis of data from the electrical utility with Omniverter and the company engineers, the decision was to install a 1500kVA 480Volt 3 phase Active Voltage Conditioner (AVC2) applied to the production line most prone to unplanned production stoppages.
The result has been a “huge improvement” according to the Plant Engineer as unplanned stoppages due to voltage sags have been eliminated and the customer states that the payback period for the AVC2 and installation has been less than 6 months.