Voltage unbalance emission assessment: sources of contribution and their ranking

etermining sources of voltage unbalance (VU) and

quantifying their individual contributions in an interconnected

network is a complex task due to multiple interactions that take

place between them. Post-connection VU emission assessment

techniques in relation to customer installations are important

not only in compliance assessment according to IEC/TR 61000-3-

13:2008 Limits - Assessment of emission limits for the connection

of unbalanced installations to MV, HV and EHV power systems,

but also in determining the various emission contributors in

the power system being considered. This paper presents a case

study on the application of a recently developed post-connection

VU emission assessment methodology to a 66 kV interconnected

sub-transmission network owned and operated by an Australian

network service provider. The study incorporates the evaluation

of constituent components of the resultant VU factors at bus bar

levels, identification of the dominant emission contributors and a

methodology for ranking of the emission contributions made by

the asymmetrical transmission lines in the network. Outcomes

obtained through the VU emission assessment methodology are

validated using three-phase, unbalanced load flow analysis.