  The oscillation phenomena associated with the control of voltage source
converters (VSCs) are widely concerning, and locating the source of these
oscillations is crucial to suppressing them; therefore, this paper presents a
locating scheme, based on the energy structure and nonlinearity detection. On
the one hand, the energy structure, which conforms with the principle of the
energy-based method and dissipativity theory, is constructed to describe the
transient energy flow for VSCs, and on this basis, a defined characteristic
quantity is implemented to narrow the scope of oscillation source location; on
the other hand, according to the self-sustained oscillation characteristics of
VSCs, an index for nonlinearity detection is applied to locate the VSCs which
produce the oscillation energy. The combination of the energy structure and
nonlinearity detection could distinguish the contributions of different VSCs to
the oscillation. The results of a case study implemented by the PSCAD/EMTDC
simulation validate the proposed scheme.
