  We have analyzed archival HST/WFPC2 time-series data of the central parts of
globular clusters M13, M30 and NGC 6712 in search of variable objects. Among a
total of 21 identified variables there are 15 new discoveries. The sample
includes nine RR Lyr stars, two SX Phe stars and seven W UMa-type contact
binaries. One object is preliminarily classified as a detached eclipsing binary
and another as an ellipsoidal variable.
