  We have recorded extreme ultraviolet spectra from $\mathrm{W^{11+}}$ to
$\mathrm{W^{15+}}$ ions using a new flat field spectrometer installed at the
Shanghai high temperature superconducting electron beam ion trap. The spectra
were recorded at beam energies ranging between 200 eV and 400 eV and showed
spectral lines/transition arrays in the 170 - 260 \AA{} region. The charge
states and spectra transitions were identified by comparison with calculations
using a detailed relativistic configuration interaction method and
collisional-radiative model, both incorporated in the Flexible Atomic Code.
Atomic structure calculations showed that the dominant emission arises from
$5d$ $\rightarrow$ $5p$ and $5p$ $\rightarrow$ $5s$ transitions. The work also
identified the ground-state configuration of $W^{13+}$ as $4f^{13}5s^2$ both
theoretically and experimentally.
