Application ofBroadcast FMforUtility Energy Management Communications

utilities on efficient energymanagement as a means tooffset the needforadditional generating capacity. Avital component ofmany oftheproposals formore efficient use ofexisting generating capacity isremotecontrol andcommunication. Someexamples of energymanagement systems whichdepend onthis communicatior channel include industrial andresidential loadmanagement demandsubscription service, anddistribution automation. Several alternatives totheproblem ofenergymanagement communication havebeenimplemented. Theseinclude powerline ripple systems, higher frequency powerline carrier systems, narrow bandFM-VHFradio, broadcast AM radio, andbroadcast FMradio. Themostwidely deployed radiocommunication system(par¬ ticularly forloadmanagement) isnarrow bandFM-VHFradio operating of154MHz.Shortage ofspectrum andtheneedtoinstall multiple transmitters toprovide adequate coverage whileavoiding "capture" ofthereceivers byother VHF-FMtransmitters, aswell as otherfactors, are obstacles towidespread development ofthis technology. Useofbroadcast radio forutility energymanagement com¬ munication isa relatively new andinteresting approach aimedat overcoming some oftheshortcomings ofnarrow bandVHF.Here theideaistosharetheexisting broadcast channel withitsnormal programming. BoththeAM andFM broadcast bandshavebeen utilized on an experimental basis forelectric utility loadmanage¬ ment andare being considered forotherenergymanagement communication needs. InthecaseofAM,thetechnique hasbeento utilize lowfrequency, lowangle phase modulation oftheAM carrier, while forbroadcast FM,theSubsidiary Communication Authoriza¬ tion(SCA) subchannel hasbeenutilized. TheFCCrules andregulations permit everyFM-broadcast station tooperate a subsidiary Communication Authorization (SCA) sub¬ channel with6KHzdeviation, centered at67KHzabovethemain