?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F323%2F&rft.title=Simplified+methods+of+assessing+the+impact+of+grid+frequency+dynamics+upon+generating+plants&rft.creator=Hunt%2C+R.&rft.creator=Fowler%2C+A.&rft.creator=Hanche-Olsen%2C+H.&rft.creator=Drye%2C+T.&rft.creator=Gilmour%2C+I.&rft.creator=McSharry%2C+P.&rft.creator=Please%2C+C.P.&rft.creator=Smith%2C+S.L.&rft.subject=Energy+and+utilities&rft.description=The+frequency+of+the+national+electricity+grid+is+affected+by+fluctuations+in+supply+and+demand%2C+and+so+continually+%22judders%22+in+an+essentially+unpredictable+fashion+around+50+Hz.+At+present+such+perturbations+do+not+seemingly+affect+Nuclear+Electric+as+most+of+their+plant+is+run+at+more+or+less+constant+load%2C+but+they+would+like+to+be+able+to+offer+the+national+grid+a+mode+of+operation+in+which+they+%22followed%22+the+grid+frequency%3A+i.e.%2C+as+the+frequency+rose+above+or+fell+below+50+Hz%2C+the+plant's+output+would+be+adjusted+so+as+to+tend+to+restore+the+frequency+to+50+Hz.+The+aim+is+to+maintain+grid+frequency+within+0.2+Hz+of+its+notional+value.+Such+a+mode+of+operation%2C+however%2C+would+cause+a+certain+amount+of+damage+to+plant+components+owing+to+the+consequent+continual+changes+in+temperature+and+pressure+within+them.%0D%0A%0D%0ANuclear+Electric+currently+have+complex+computational+models+of+how+plants+will+behave+under+these+conditions%2C+which+allows+them+to+compute+plant+data+(e.g.%2C+reactor+temperatures)+from+given+grid+frequency+data.+One+approach+to+damage+assessment+would+require+several+years'-worth+of+real+grid+data+to+be+fed+into+this+model+and+the+corresponding+damage+computed+(via+%22cycle+distributions%22+created+by+their+damage+experts).+The+results+of+this+analysis+would+demonstrate+one+of+three+possibilities%3A+the+damage+may+be+acceptable+under+all+reasonable+operating+conditions%3B+or+it+may+be+acceptable+except+in+the+case+of+an+exceptional+abrupt+change+in+grid+frequency+(caused+by+power+transmission+line+failure%2C+or+another+power+station+suddenly+going+off-line%2C+for+instance)%2C+in+which+case+some+kind+of+backup+supply+(e.g.%2C+gas+boilers)+would+be+required%3B+or+it+may+simply+be+unacceptable.%0D%0A%0D%0AHowever%2C+their+current+model+runs+in+approximately+real+time%2C+making+it+inappropriate+for+such+a+large+amount+of+data%3A+our+problem+was+to+suggest+alternative+approaches.+Specifically%2C+we+were+asked+the+following+questions%3A%0D%0A%0D%0A-+Can+component+damage+be+reliably+estimated+directly+from+cycle+distributions+of+grid+frequency%3F+i.e.%2C+are+there+maps+from+frequency+cycle+distributions+to+plant+parameter+cycle+distributions%3F%0D%0A%0D%0A-+Can+a+simple+model+of+plant+dynamics+be+used+to+assess+the+potential+for+such+maps%3F%0D%0A%0D%0A-+What+methods+can+be+used+to+select+representative+samples+of+grid+frequency+behaviour%3F%0D%0A%0D%0A-+What+weightings+should+be+applied+to+the+selections%3F%0D%0A%0D%0A-+Is+it+possible+to+construct+a+%22cycle+transform%22+(Fourier+transform)+which+will+capture+the+essential+features+of+grid+frequency+and+which+can+then+be+inverted+to+generate+simulated+frequency+transients%3F%0D%0A%0D%0AWe+did+not+consider+this+last+question%2C+other+than+to+say+%22probably+not%22.%0D%0A%0D%0AWe+were+supplied+with+data+of+the+actual+grid+frequency+measurements+for+the+evening+of+29%2F7%2F95%2C+and+the+corresponding+plant+responses+(obtained+using+Nuclear+Electric's+current+computational+model).+A+simplified+nonlinear+mathematical+model+of+the+plant+was+also+provided.%0D%0A%0D%0ATwo+main+approaches+were+considered%3A+statistical+prediction+and+analytical+modelling+via+a+reduction+of+the+simplified+plant+model.&rft.date=1996&rft.type=Study+Group+Report&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F323%2F1%2FAssessing-the-impact-of-grid-frequency-dynamics-upon-generating-plants.pdf&rft.identifier=++Hunt%2C+R.+and+Fowler%2C+A.+and+Hanche-Olsen%2C+H.+and+Drye%2C+T.+and+Gilmour%2C+I.+and+McSharry%2C+P.+and+Please%2C+C.P.+and+Smith%2C+S.L.++(1996)+Simplified+methods+of+assessing+the+impact+of+grid+frequency+dynamics+upon+generating+plants.++%5BStudy+Group+Report%5D+++++