Power distribution monitoring systems are enhanced and now include power quality analysis capabilities and unlimited trip curve shaping.
What's new in electrical products and technologies? Well, the Electric West 95 Show held in Anaheim, Calif. last month highlighted many new products. From a performance viewpoint, however, there are some surprises. One such surprise is the enhanced performance of power distribution monitoring systems.
These sophisticated systems, which were first introduced in the late '80s by the four major power distribution switchgear manufacturers, have been dramatically improved. Included now are power quality analysis, proactive circuit protection, energy conservation, and enhanced communication with electronic trip units and solid state starters. What was once a passive technology has now become very proactive.
Next generation equipment
When first introduced, the typical power distribution monitoring system did just about what its name implied; that is, it passively monitored the performance of a system and took real-time measurements of such parameters as amperage, phase-to-phase and phase-to-neutral voltage, power factor, vars, frequency, demand watts, etc. The brains of the system, the microprocessor, was located in the electronic trip units of main and feeder circuit breakers and electronic starters. This, more or less, remains the case today.
One area of power distribution monitoring, protection, and coordination, has advanced into the next generation so to speak. We're all familiar with the manual operation of adjusting the curve shape for an electronic trip unit in a breaker. We take out the venerable small screw driver and make the necessary settings at the face of the trip unit.
Now, however, with the introduction of a new solid state electronic trip unit with built-in communications capability and an enhanced monitoring system by one manufacturer, you can proactively shape a breaker's trip curve from your computer, with virtually infinite settings for optimum system coordination. Also included are extended curve shaping options such as long delay [I.sup.4]t settings for example. You can even have Zone Selective Interlocking down to a 70A molded case circuit breaker.
Think about it. You can actively compensate for temporary load changes such as large motor repairs and scheduled partial system outages, all from your desk.
Power quality analysis
One predominant feature shown with most power distribution monitoring systems is power quality analysis. Want a spectrum analysis on a certain feeder? You've got it. Want to see the voltage and current wave-forms? No problem. Want a listing of transients including sags, swells, their magnitude, the time and date of the specific transient? It's at your finger tips. What about percent Total Harmonic Distortion (THD) on current and voltage, system or feeder k-factor, CBEMA derating factor, crest factor? The information is available. And all of these data can be downloaded into a computer for historical logging and future printout. The use of a point-and-click program makes the system user friendly.
These new power distribution monitoring systems, coupled with electronic trip units having microprocessors, allow you to monitor power usage at the feeder level. Thus, accurate energy allocation budgeting is attainable. As with power quality analysis, this information can be down-loaded into a computer and logged for future reference, historical record keeping, and report generation.
What's new in wire connectors?
Even the mundane twist-on wire connector has gone hi-tech. Highlighted at the show were two brands of water-tight twist-on connectors. Instead of expensive and time consuming poured water-tight splices, we can now use these quick, inexpensive devices in damp environments without fear of future connection problems.
We also have twist-on connectors with extended skirts, flexible skirts, and sealed skirts for improved bare conductor coverage in device and junction boxes.
One new and historically requested product introduced at the show was a twist-on connector for aluminum-to-copper connections. The device has a specially formulated compound within it that cuts aluminum oxide and prevents corrosion. To counter the "cold flow" characteristic of aluminum, the connector has a live-action spring that expands and contracts. This product will attract much attention.