  We report a study of the eclipse timing variation (ETV) of short period
($P_1\le 6^d$) eclipsing binaries (EB) monitored during the photometric survey
OGLE-IV. From the 425\,193 EBs we selected approximately 80\,000 binaries that
we found suitable for further examination. Among them we identified 992
potential hierarchical triple (or multiple ) system candidates exhibiting
light-travel-time effect (LTTE). Besides, we obtained the orbital parameters of
these systems and carried out statistical analyses on the properties of these
candidates. We found that (i) there is a significant lack of triple systems
where the outer period is less than 500 days; (ii) the distribution of the
outer eccentricities has a maximum around $e_2\approx0.3$; (iii) the outer mass
ratio calculated from an estimated minimum mass of the third component is lower
than $q_2\sim 0.5$ for the majority of the sample. We also present some systems
that deserve special attention. (i) There are four candidates that show double
periodic ETV, which we explain by the presence of a fourth companion. (ii) For
two systems the perturbations of the third component are also found to be
significant therefore we give a combined dynamical and LTTE ETV solution. (iii)
For one system the third component is found to be probably in the substellar
mass domain.
