Distribution Substation Automation-Fixing a “Failure to Communicate”

 

It is surprising to most people who are not familiar with the details of the electric industry that utilities do not typically have extensive and continuous monitoring of all their critical equipment. While the installation of SCADA (supervisory control and data acquisition) systems at distribution substations provides some remote monitoring capabilities, many distribution substations have no SCADA and those that do usually rely on dial up communications (over leased phone lines) or its equivalent in terms of low bandwidth.

In these “low tech” circumstances, when a substation sends a serious alarm to the system control center, the system operator’s first reaction is to determine the availability of qualified company personnel to drive to the substation to conduct a visual inspection. In today’s environment of widespread and low cost video surveillance cameras, it is hard to comprehend that an asset as large and important as a distribution substation does not have a device as simple as the web cam that is a standard feature on so many Internet-enabled laptops and cell phones today. This is commonly the first step to substation automation – some form of basic monitoring.

The true objective from substation automation, though, is not video surveillance but a host of other types of condition monitoring capabilities that will support the substation in operating more efficiently at less risk:

• “Smart” relays provide valuable information about faults, including distance to fault and in some cases type of fault.
• Transformer monitoring capabilities that show loadings and transformer operating conditions such as pressure, temperature, and dissolved gas in oil (DGOA).
• Algorithms that combine different sensor values to create a more precise diagnostic of abnormal conditions can be employed. These represent some of the initial steps toward a “Smart Grid”.

And as more automation approaches and/or requirements are identified (e.g. adaptive relaying, enhanced physical security), the substation automation will play a larger role in terms of lower operating costs and improved response.