I was interested in knowing what triggered the last two LHO wind locklosses, so I ran an analysis code to try understand what dofs are the culprit.

In both case (#1 1247970127 and #2 : 1247975795), the online lockloss show EX L2 saturating first.

The drive is dominated by the length signal for both instances which I presume is from DARM. This is shown in the time series breakdown in figure1 and figure2, where we see that the blue curve (length signal) is the largest contributor to the sum of L, P and Y drives. At LLO one of our wind lockloss was rather from an angular dof saturating L2 EX (see 45237).

Looking at the spectra of the individual dofs contributing to the actuator signal, we see the length drive dominates largely up to 0.3Hz, see figure3 and figure4.

Comparing various control signals spectra for event #1 at the begining vs end of the lock (less vs more windy), we see the main difference is below 0.5Hz, with a factor of ~5 increase of the drives (for a x2 wind speed increase), see figure5.

Note that for both locklosses, L1 stage of EX is only using at most a fifth of its drive range (figure6), so it might be worth increasing the L1 EX control authority for DARM.