Optimal Capacitor Placeinelit, Replacenlent and Control in Large-scale Unbalanced Distriliution Systcnis: System Solutio11 Algorithms and Nuiiierical Studies

This paper develops an effect.ive and, yet, prac- tical solnt,ion met,hodology for optimal capacit,or placement, replacement and cont.rol in large-scale nnhalhnred, general radial or loop dist.ribntion syst.ems. The solution methodol- ogy can optimally det,erniine (i) t.he locations 1.0 inst.all (or replace, or remove) capacit.ors, (ii) t,he t.ypes and sizes of ca- pacit,ors t,o he inst,alled (or replaced) and, during each load level, (iii) the control schemes for ea.cli capacitor in the nodes of a general three-phase unhalancrd dist.rihotion system snrh that a desired ohject,ive hnct,ion is niininiized while the load constraints, network const.raints and operational constraints at different load levels are sabisfied. The solut.ion met.liod- ology is based on a conihinat.ion of llie simnlatrd annral- ing technique and t,he greedy search t.echnique in order 1.0 achieve compnt.at.ional speed and high-qnalit.g ol solnt.ions. Bot.11 the numerical and iriiplenlent.at.iona1 a$pect.s of t,lie so- lotion methodology are det.ailed. Analysis of t.he compnt.a- t,ional comp1exit.y of the solnt.ion algorit.lim indicates t,liat. t.lie algorithm is also effect,ive for large-scale dist.rihnt.ioo systems in terms of compnt,at.ional efforts. Test. res~~lbs on a realistic; nnbalanced distrihnt.ion net.rvork, a ?91-bns with 77 la.t.erals, 3n5 dist.ribnt,ion lines and fi t.ransfornters, wit.11 varying load- ing condil.ions, are presented wit.li proinising resnlls. 'The robustness of the solut,ion methodology under varying lod- ing conditions is also invest,ignt,etl.