Continuous Process Lines

• High-value items
• Continuous processes
• High-speed manufacturing

High-speed manufacturing lines have become more agile and advanced. These industries include food and beverage, dairy, pharma, semiconductor, etc. Advances include smart packaging, non-destructive inspection methods, embedded sensors, robotics, power electronic equipment, and automation, etc.

These technologies are energy-efficient equipment with electronic control systems to increase efficiency. In many of these cases, these technologies are sensitive to power quality variations. Any interruptions of a critical process will result in significant financial loss.

Customer challenges

Machine breakdowns,?Equipment premature failure, Tooling damage, Unplanned maintenance, PLC malfunction and electronic card failures, Process/Machine adjustments, Process resetting time, Material wastage/cleanup, Adjustment of parameters during the cleanup, and restart, etc.

Possible Causes

• Voltage Sags - Weather conditions are a significant contributor to voltage sags. Sags and momentary interruptions are often at fault for process interruptions.
• Momentary power loss – Causes include recloser operation, switching, utility faults breaker tripping, electronic failure of equipment.
• Harmonics – Non-linear loads like rectifiers, switching power supplies. Other causes include pulse-width inverters, static frequency converters, induction furnaces, welding arching devices.
• Resonance Conditions – Flicker is one resonance condition. The most common cause is arc furnaces, ball mills, car shredders, and rock crushers

Case Study at a continuous food process plant

The Situation/Problem

An international food company has large bakery operations in the Southern USA for the production of baked goods on multiple lines.?It is a continuous operation and is located in a mixed industrial/residential district.

It periodically experiences unplanned production stoppages which can result in products being burned inside the ovens. If this happens the entire product in the ovens is lost and a cleanup period of several hours is needed before normal production can be restored.?If the product catches fire in the ovens, then clouds of black smoke can cover the neighborhood to the discomfort of local residents notwithstanding the high costs.?

The Analysis and Diagnosis

The plant is supplied via the local electrical utility at medium voltage 20kV and there are several transformers on-site to provide the operating voltage of 480V. The company and the utility installed power quality monitors.?The data produced showed almost all events were due to voltage sags which occur mainly during storms and bad weather.

Omniverter was given data from the site and company management decided that they wished to apply any solution to one critical line which produces several million cookies per week

Solution

The Omniverter solution was a 1500kVA 480V Active Voltage Conditioner (AVC) which is designed to correct both 3- phase voltage sags and single-phase voltage sags which occur more frequently.?The response time of the AVC allows full correction within less than ? cycle (< 5 milliseconds). The AVC was supplied together with bypass switchgear and includes integral power quality monitors.?

The Impact and ROI

The results according to the Plant Engineer have been a “huge improvement” as unplanned stoppages due to voltage sags have been eliminated and the customer states that the payback period for the AVC and installation has been “less than 6 months”