You’re reading an outdated article. Please go to the recent issues to find up-to-date content.
The focus of this column is usually on power quality or variations in voltage provided by the source that are the result of interactions with the load and source impedances, as well as the voltage and current requirements of the equipment using the electricity to provide useful and often uninterruptible work. However, a recent meeting with a person who deals with issues of homeland security raised the question about the relationship between power quality and the security of the generation, transmission, distribution and utilization of electricity.
By coincidence, there was a television show on the night before the meeting about a terrorist plot to “inject waveforms” into their wall outlet that would propagate through to the distribution system and then the transmission system, eventually taking out the generators. Sounds a bit far-fetched, but then again, other events in the past decade seemed improbable prior to their occurrence.
Also during the meeting, the comment was raised that we, the information media, have provided the knowledge to terrorists on how and where such a cascading failure could be carried out.
There are ways and means to bring parts of the grid to a screeching halt. For example, the August 2003 blackout started with trees getting too close to strained transmission lines followed by a series of events caused by human and system errors, which led to more than 16-hour blackouts for some businesses with the highest dollars/hour need for high nines of power quality.
As not to provide any further credence to the comment about providing any information to those who would seek to destroy our way of life, it would be difficult to suggest ways the government could help to prevent such without revealing the vulnerabilities of the system. Obviously, it is nearly economically and physically impossible to protect the entire grid, since every electrical outlet is connected back somehow.
However, the government response in the aftermath of the August 2003 blackout was mostly in the form of a large report on the incident, though there also was some pressure from Federal Energy Regulatory Commission (FERC) to move forward with the IEEE 1547 series of standards on interconnected distributed resources to the electric power system. The U.S. Federal Energy Policy Act of 2005 also called for state commissions to consider certain standards for electric utilities. So, should the government do more through legislation and funding to make the power system more secure?
Rather than start a debate about whether more or less government regulation is a good or bad thing, perhaps a slight modification of President Kennedy’s famous 1961 inaugural address would be a better tack: Ask not what the government can do for your power security. Ask what you can do for your own power security.
Basic but grounded
The first step is to understand what the critical loads in the facility require for power and if they already are properly wired to accommodate a separate source of power. There are countless case studies in mission-critical facilities, such as hospitals, where it wasn’t until they actually lost power from the electric utility that they found out some critical loads were no longer energized, and noncritical loads were still energized, needlessly draining the reduced capacity of the backup power source.
The next step is to determine how best to provide the required power. Does the load require a “bumpless” transfer where there is no interruption, or can the process be restarted quickly after the transfer without any significant loss of production or operation? Some loads cannot tolerate even a cycle drop out. Typical power quality audits and analyses should be conducted to fix this problem, since such events are quite typical under normal circumstances.
How long does the process need to operate without utility power? In some cases, power is needed only for an orderly shutdown of the process; in other cases, it must run until it drops, such as in the case of a 911 call center. Hopefully, the next revision to the National Electrical Code will contain a new article that has been worked on for the past couple of years by Code Making Panel 20, which addresses the requirements for these mission-critical facilities.
Another NFPA document, NFPA 70B Recommended Practice for Electrical Equipment Maintenance, provides further useful information on the commissioning, testing and maintenance of these systems.
Having procured the necessary alternate power sources, commissioning of the system followed by periodic maintenance and testing is essential to ensure it will be fully operational when it is needed. The excuse, “I don’t want to test it in case the test would cause it to fail,” is about as lame an excuse that exists, but it has been used more than once.
In the end, one can either pray nothing happens or be proactive and prepared for either a power security event or the more common power quality event. The benefits of the proactive approach clearly outweigh any costs.
BINGHAM, a contributing editor for power quality, can be reached at 732.287.3680.