  The recent detection of very high energy (VHE) emissions from flat spectrum
radio quasars (FSRQs) at high redshifts has revealed that the universe is more
transparent to VHE $\gamma$-rays than it was expected. It has also questioned
the plausible VHE emission mechanism responsible for these objects.
Particularly for FSRQs, the $\gamma$-ray emission is attributed to the external
Compton process (EC). We perform a detailed spectral study of
\emph{Fermi}-detected FSRQ 3C 345 using synchrotron, synchrotron self Compton
(SSC) and EC emission mechanisms. The simultaneous data available in optical,
UV, X-ray, and $\gamma$-ray energy bands is statistically fitted under these
emission mechanisms using the $\chi^2$-minimization technique. Three high flux
states and one low flux state are chosen for spectral fitting. The broadband
spectral energy distribution (SED) during these flux states is fitted under
different target photon temperatures, and the model VHE flux is compared with
the 50\hspace{0.05cm}hr CTA sensitivity. Our results indicate a significant VHE
emission could be attained during the high flux state from MJD 59635-59715 when
the target photon temperature is within 900K to 1200K. Furthermore, our study
shows a clear trend of variation in the bulk Lorentz factor of the emission
region as the source transits through different flux states. We also note that
during high $\gamma$-ray flux states, an increase in external photon
temperature demands high bulk Lorentz factors, while this behaviour reverses in
case of low $\gamma$-ray flux state.
