Hi Dnk,
I think that alot of utils know that they have equipment that needs swapped out but don't have the resources to do it on a PM basis. So things just blow sometimes when they aren't overloaded. Everyone's trying to cut corners these days. If you're at all like me, you've probably told folks, "Gee, I don't think we can afford to save this much money!"
We have 60+ traction power substations(I lost count). A few years ago, we installed one modem in each substation adjacent to our main metering. They are set to take many rings to answer, but when they do, the utility polls for inflow & outflow data for each line.
More recently, we started using our SCADA(Supervisory Control And Data Acquisition) system to gather our own power usage data. I had to build interfaces to adapt the common negatives of what appear to be opto-interruptor outputs with open collectors, to our SCADA +48 common scheme. Each meter puts out pulses for inflow and outflow. We need this because the utility is sending power across our tie bus that we aren't using.
The SCADA RTUs have a function referred to as "Accumulators", where pulses applied to certain status inputs are counted between special polls and returned like an analog value, instead of an instantaneous "0" or "1".
The MASTER end takes the data and plugs & chugs to get current hour, previous hour,day, week, month, Et,c. It's all data base manipulation at this point.
Are you just interested in monitoring or perhaps high demand load shedding? I think most folks use load shedding to avoid high demand charges or at the utility's request, rather than expecting to take out a TX if they don't.
Joe
[This message has been edited by JoeTestingEngr who dangled his participle & misplaced his modifier. (edited 12-10-2005).]
[This message has been edited by JoeTestingEngr (edited 12-10-2005).]
