Evaluating the Economics of Power Conditioning Alternative
Our company is dependent on highly integrated process lines that are composed of very sensitive devices. It doesn't take a blackout to trip these lines out of service, and when they're out of service, we're losing money. We wanted to determine if there were power conditioning alternatives that were economically justifiable given the sensitivity of our equipment, the electrical environment in which we have to operate, and the costs associated with downtime and the mitigation technologies available to us. Power quality monitoring at our facility provided us with a background characterization of the electrical environment that served as the first step in determining if we would be economically better off investing in some sort of conditioning solution. The web interface to the data also provided us with quick feedback when a process line would trip. Within minutes, we could access the web site, look at the data, and know if the problem was related to a utility event or was a problem internal to our facility. This allowed us to communicate our problems and concerns more effectively and confidently to our electricity provider. As a result, we were able to successfully apply power conditioning equipment and improve our system performance.
Power Conditioner Input Voltage
Power Conditioner Output Voltage
| top |
IEEE Std. 519 Compliance Evaluation
Our facility experienced several power quality problems after we installed a number of large adjustable-speed drives. We also realized that we were paying a high monthly penalty due to poor power factor. We consulted our utility and were advised that the application of harmonic filters could potentially solve both problems. We were also told that our harmonic solution would require compliance with current limits provided in IEEE Std. 519. However, we had no convenient and cost-effective means to verify the performance of the filters and assure compliance with the requirement. We turned to powermonitoring.com for the solution. Their monitoring service provided us with the harmonic and energy trending data that we needed to verify the effectiveness of the harmonic filters for both harmonic and power factor control. The data was easily accessible over the web and their monthly reporting provided the required compliance documentation. As a result, we have reduced our monthly energy bills and eliminated the harmonic problems that were affecting our equipment.
Harmonic Current Evaluation - Harmonic Current Trend
| top |
Our utility has undertaken a multi-year effort to assess the quality of power on our system and for our most important customers. Our goal is to monitor and process power quality data throughout our system. Results of this effort will be provided to our customers so that they may make better decisions regarding power conditioning alternatives and modify their equipment procurement specifications so that new equipment will be immune to the most common power quality events on our system. This effort includes several stages. The first stage involved a proof-of-concept and monitoring system specification. We utilized the monitoring service from powermonitoring.com for this stage. The second phase involved installation of a complete monitoring system that will gather and process the monitored data. For this stage, we purchased a system from Electrotek Systems that included the data analysis tool PQView. We also use PQWeb for viewing the data via the Internet.
System Benchmarking - Magnitude-Duration Histogram
| top |
Monitoring and the Power Quality Economic Simulator
Using the Power Quality Economic Simulator (PQES) to Evaluate the Economics of Power Conditioning Alternatives
The PQES software program was used to evaluate the economics associated with various power quality improvement alternatives for a major industrial customer. Plant personnel estimated the cost of interruptions and sags for the facility while the power quality history was obtained from the powermonitoring.com system installed at the utility substation and within the customers facility. The total annual "Power Quality Cost" for a facility consists of two components: the cost associated with sags and/or interruptions (Red bar in Figure 1) and the cost associated with any mitigating technology that reduces the annual number of sags and/or interruptions (Green Bar). Various power quality improvement options like constant voltage transformers (CVT) for control circuits, a primary static switch, static voltage regulators and large UPS supplies were evaluated and compared against the "Do Nothing" base case. For this particular customer, the solution that minimized their total annual cost was the installation of CVTs at critical control locations.
Economics of Power Conditioning Alternatives
| top |