Transmission & Distribution World December 1996

By Chuck Newton, Automation Editor

As I have stated before in this column, justifying a business case for all types of T&D technology is increasingly critical with the dawn of the competitive utility era. Substation automation is no exception. Respondents from a recent substation automation study ranked the "lack of economic and business justification" as the most important potential obstacle to implementing substation automation programs (Table 1).

Managements interest in programs varies depending on whether the issue is retrofitting older substations or constructing new state-of-the-art substations. For both new and retrofit substation programs, the primary financial benefit listed by the survey respondents was "reduced time to find and fix problems." This was followed by "reduced primary equipment maintenance cost" and "reduced O&M cost for protection and control devices." For new applications, "reduced wiring costs" was also identified as an important benefit.

A review of responses from operations personnel revealed 16 potential benefits associated with substation automation and integration programs. The 100 substation planning engineers and managers surveyed said that the most important issues to them were "limiting impact on customers due to outages," "faster operational decisions made with more timely data," "improved access to substation data" and "improved power system flexibility and reliability (see chart)."

Data Requirements

"Alarm data" is the most important type of substation information that must be reported back on a continuous basis to the master station location. However, alarm data is just one of a cluster of data points to be reported continuously. Other key items include circuit breaker status, line voltage readings and real-time data sampling (watts, VARs, volts, and amps).

Within the substation, smart RTUs are continuing to rule the roost. Seperate microcomputers edge programmable logic controllers in mention of primary information task handlers in a substation automation environment.

For transmission class substations, two activities were ranked at the top of a long list of key components. "Remote access for (EMS) operations data retrieval" and "sequence of events recording" were both ranked as the most important activities. These two were followed by "metering" and "monitoring of transformer equipment." For distribution class substations, "monitoring of breakers" was followed by "monitoring of transformer equipment" and "metering."

When asked what are the most important measurements used to determine power quality at the substation level, respondents cited "voltage sags and swells" as the key measurement, with "min/max volts" and "voltage transients" tied for second in importance.

Emerging Trends

Utility engineering staffs participating in this research program reported "an increased recognition, understanding and acceptance of the benefits and importance of substation automation" by a whopping 73% versus 25% who did not report such a change over the last 24 months.

Further, two-thirds of the respondents also see increased "adoption and implementation of substation automation technology" at their utilities. Perhaps this explains the increased levels of spending on substation automation being forcasted over the 1996-1998 period by these same spokespersons. If these substation spending forecasts come to fruition, a truly happy new year will be the order of the day for the important utility customers, utility automation planning staffs and the substation automation and integration supplier community.