Distribution Automation: How Will It Fit Into a Changing Industry?
By Teresa Hansen, Managing Editor
Even though some great technology strides have been made in recent years, convincing today`s utility management to spend money on distribution systems is becoming harder and harder. According to Kay Clinard, a principal consultant with KEMA Consulting Co., and John Redmon, Public Service Electric and Gas Co. and IEEE`s distribution automation working group chairman, the distribution automation industry does not need any new technology breakthroughs to prosper. “The technology is here,” said Clinard. The hurdle is choosing the right technology and then justifying the cost to upper management, he said.
Since as early as the 1960s, utilities have been automating their distribution systems. Although early distribution automation was very simple and somewhat antiquated compared to today`s standards, its purpose has basically always been the same–improve system operating efficiency and reliability. That has been true with both small and large utilities in urban or rural settings. However, improved reliability as a justification for investing in distribution automation has always been a hard sell. According to Redmon, a system must be in “pretty bad shape” for reliability to be the only cost justification. “Traditionally, reliability improvements provided only a small portion of the business case for automation,” added Clinard.
It is expected that utilities` distribution functions will become the “wires” companies in the competitive environment. These distribution companies will most likely remain regulated by state public utility commissions. The distribution lines and equipment in these newly created wires companies will be their primary assets. Just as with any company, wires companies will be expected to turn a profit, meaning they must be able to see quick pay back from any investments made in the distribution system. “A utility can no longer afford to use the philosophy of when in doubt, overbuild,” said Redmon. “However, it must still make everything work well.”
One issue that is likely to have a big impact on making sure that system performance is up to par, while creating an opportunity for wires companies to increase profit is performance based rates (PBR). State utility commissions throughout the country are introducing PBR to make sure that wires companies operate at an acceptable level. “PBR provides the `dangling carrot` incentive for wires utilities to maintain and improve their reliability,” Clinard said. Typically, if the performance degrades below some historic mean, then the utility is fined. If the performance improves beyond a goal, based on the same historic mean, the utility is rewarded. “The reward system provides an added incentive to install features such as remote feeder switching to improve reliability, and results in reliability improvement justifications for much higher percentages of the system,” Clinard added. “Traditional distribution functionality, however, is still needed in conjunction with the reliability improvements to share the costs.” Most experts agree with Clinard, feeling these requirements will have a big influence on future distribution automation projects.
Even with the changing economic environment and overall acceptable reliability, there are still some very strong, solid arguments for investing in distribution automation. Although technology improvements alone will probably not justify more spending, the information that will become available due to technology advancements just might.
As the figure indicates, over the past 10 years, the trend has been for utilities to implement distribution automation technologies. The figure also shows that since the late 1980s, distribution automation has focused on volt/var strategies and trouble call improvements. Recently, features such as remote switching, substation automation, automatic meter reading and customer load management have also been added. This trend is expected to continue into the next century, focusing on integrating these features and expanding their capabilities.
These new capabilities may provide incentive for many utilities to use distribution automation to gather data about customers, including billing and account data. Clinard expects that data will be gathered via the distribution infrastructure and used by various utility groups to develop services that will improve customer care. These expanded distribution automation functions may also lead to the development of new revenue sources for many utilities, thus increasing distribution automation spending.
Distribution Automation Star
At the recent DistribuTECH `99 Conference and Exhibition held in San Diego, Larry Clark, Alabama Power Co.`s (APC`s) principal engineer responsible for the company`s distribution automation program, spoke about APC`s experiences with distribution automation. He also explained a concept that he called the distribution automation star (see illustration). Clark emphasized that it is important to maximize distribution automation by considering all the functions the devices are capable of performing. The points that Clark brought out in his discussion about the star may also make a strong argument for distribution automation improvements and investments.
Distribution automation is a multi-featured system, Clark said. It obviously contains the functionality for which it was installed; however, it provides even more. According to Clark, every device on the system is an operations point, a fault detection device, a planning tool and a power quality tool.
Clark explained that it is easy to determine the functionality of each device. At APC, the distribution automation system consists of line monitoring devices, automated line switches and reclosers. Lately, the utility has also begun switching distribution automation line capacitors using remote terminal units (RTUs) integrated with switch capacitors on the poles.
In explaining how distribution automation devices are operations points, Clark pointed out that every device allows operators to monitor the system. APC`s operators use the distribution automation system to not only control devices, but also to perform remote line switching and some substation switching, Clark said. The APC operators also use the system to detect faulted sections, as well as support service restoration on unfaulted sections, improving field personnel`s efficiency, he said.
Perhaps one of the most important features highlighted in the distribution automation star is the planning tool. Clark explained that through the system`s database server, APC planning engineers obtain snapshots of SCADA data for the entire system. The utility currently distributes event summaries monthly via CD ROM to all planning engineers. By doing this, SCADA data, which has traditionally been only an operational tool, has been expanded into the planning environment. The most important aspect of this whole exercise is that it helps APC better utilize its capital expenditures. “We are optimizing our capital dollars because we have real time SCADA data that defines the system,” Clark said.
Finally, Clark spoke about distribution automation and power quality. Power quality issues are growing, he said. The current distribution devices and distribution lines can supply harmonic content up to the fifteenth harmonic. “Distribution automation devices can be the first line defense in determining where power quality problems exist,” Clark said. “(A utility) can attack and improve customer satisfaction with this capability.”
Clark emphasized that when justifying distribution automation investments, it is important to look at the whole system and its capabilities. “Distribution automation is multidimensional and provides benefits to many areas,” he said.
The distribution business is changing and evolving just like the rest of the utility business. Justifying distribution automation expenditures is even more difficult and involved than it once was. However, that doesn`t mean there are not solid reasons to continue to implement distribution automation programs. If implemented correctly, distribution automation will continue to play a major role in the changing utility industry.