The basics of manufacturing are very similar to the production line introduced by Henry Ford at the start of the industrial revolution.
Today, this model has been implemented by various industries worldwide, where production is arranged into work stations and the product travels by each station. However, the equipment being produced and the manufacturing tools needed to create that equipment has changed considerably over the years. For example, painting is performed using electrostatic charges and ultimate testing is automated with the help of PCs. Today, robots are welding car components, instead of people.
In contemporary factories, high quality electrical energy is necessary to sustain their performance at their peak level, and power protection factors are not necessarily relegated to the control systems alone.
What Are We Protecting?
The following aspects have to be considered when making informed decisions about customers’ requirements for power protection:
- What are the types of loads in the factory and their electrical requirements?
- What happens to their process if there is a voltage sag or interruption?
- What is the quality of the power delivered from the utility?
Generally, factory managers are aware of the first two points, but at times the power quality data obtained from the utility is not known. This could be attributed to the fact that that such data is not determined by the utility, or it may be determined at the substation which may not provide an exact picture of the voltage issues existing at the customer’s facility. However, factory managers should be able to answer this question - What most frequently causes problems for your facility power quality events or outages?
The answer to this question is power quality events, unless the outages are less frequent or the utility grid is quite poor. Other issues can include the temporary dip in the lights, resulting in the tripping of variable speed drives and under-voltage relays. Such power quality events indicate that voltage conditioning can prove advantageous to customers. To overcome such instances of outages, ABB offers a wide range of UPS.
Another critical factor that needs to be considered is how these power quality events impact the production process and their subsequent impact on the customer. This analysis helps in gaining a better insight into the business case.
Normally, when the process is more complicated, there is less possibility of recovering the product from the production line and this in turn would lead to increased scrap costs. A significant amount of time would also be required to recalibrate or clean the manufacturing line which not only increases the costs, but also causes unnecessary delays, all of which means customers may not be able to keep up their delivery schedules.
In the worst scenario, the product or equipment may get damaged because when the voltage recovers, a surge of current may travel back to the equipment. Therefore, such damage is not caused by voltage sags alone. An example of this problem is shown in Figure 1. A normal front end rectifier for a variable speed drive or power supply is also shown.
Figure 1. Top normal controlled start up process. Bottom In rush currents following a voltage sag
At the time of a voltage sag, two options can be considered for the behavior of this load:
- Trip offline and carry out a controlled restart; operator intervention may be needed for this process and will involve some amount of time.
- In case there is sufficient energy in the DC link capacitors, ride via the sag. Nevertheless, when the voltage recovers this is where the issue lies and large amount of surge currents can possibly affect the equipment.
The Smart Utility Grid - More or Less Reliable?
In the past few years, there have been some substantial changes in the utility grid structure. Such distributed generation and smart grid are ever present in the media. The effect of distributed generation has raised some major concerns, especially our dependability towards smart grid. As a result, the grid is becoming less and less reliable.
A bigger issue relates to voltage regulation. This can be attributed to the generation at the distribution level, which was not planned in this manner in the past. In addition, this generation is not regular, posing further difficulties to utilities to sustain the grid stability. Whilst distributed generation does not help much, weather events continue to remain the major cause of power quality events on the grid.
Figure 2. Recording of PCS100 AVC performance
Figure 2 illustrates a plot of the output and input voltages over a period of 12 months from a PCS100 AVC deployed in Philippines. Storms are common in this region, causing confusion in the utility grid. Voltage sags are frequent issues during this season, with 129 power quality events recorded over a period of one year. However, by using the ABB PCS100 AVC (Figure 3), a large number of events are changed back to nominal voltage.
Figure 3. PCS100 AVC
Back to Business
Power protection is considered only when customers can benefit from a positive cost/benefit ratio. However, customers already know the benefit ratio since it is their factory and equipment and hence can easily determine the advantage of less equipment failures and production interruptions. However, some amount of costs would be still be involved. To overcome this issue, ABB’s PCS100 AVC provides a total cost of ownership, particularly in case of higher power loads, where costs relating to power protection may have been excess in the past. The table given below highlights the features of the PCS100 AVC.
Table 1. Features of PCS100 AVC
||PCS100 AVC features
||Competitive especially for larger loads where power protection costs may have been prohibitive in the past.
||Small footprint. 3 phase AC in and 3 phase AC out are the only connections needed.
|Operating costs - energy
||Very high energy efficiency minimizing energy consumption and ventilation requirements.
|Operating costs - maintenance
||Minimal maintenance required. No batteries to maintain or replace, 20 year design lifetime with maintenance at 10 years (cooling fans only at 5 years).
Power protection schemes do not provide an all-in-one solution to customers. It is important to consider customers’ unique process needs, utility quality and the potential outcome during power quality events. In case voltage conditioning has to be used, customers can utilize the ABB PCS100 AVC. They can be rest assured that more than 685 MVA of PCS100 AVCs have been deployed across the globe.
About ABB Power Conditioning - Discrete Automation and Motion Division
ABB is a leading supplier of UPS and power conditioning products – ABB's PCS100 portfolio is a unique line up of low and medium voltage power conversion technology. The PCS100 power converters demonstrate highly reliable and cost-effective performance. With the PCS100 product portfolio, ABB offer efficient power conversion solutions that are specifically designed to solve power quality problems and stabilize networks. Covering applications from data centers through to complete industrial plant protection, microgrid systems and shore-to-ship supply, ABB have the power conversion technology for every need. Starting from a few kVA to many MVA and a wide range of supply voltages. ABB has installed more than 900 MW of power conditioning solutions worldwide. It’s business as usual with ABB Power Protection.
This information has been sourced, reviewed and adapted from materials provided by ABB Power Conditioning - Discrete Automation and Motion Division.
For more information on this source, please visit ABB Power Conditioning - Discrete Automation and Motion Division.