I don't know about the Western countries, but the problem of lizards or say vermin in electrical substations seems to be problem with no solution at least in India. Recently even after fortnightly checks on vermin proofing, there was a flash over in one of the 11kV panel in our plant leading to unwanted shutdown, suggestions will appreciated for control the vermin proofing of the substations.Glue pads, fumigation sealing etc. are done as much as possible.

Maybe a cat could solve your problem?

Operators should check and ensure all doors are locked during their routines
Maintenance personel should replace seals and ensure panels are screwed or bolted in properly.
Fire and vermin proofing should also be in place.
Usually vermin follows the food chain.break the chain .

Further to Ole Knudsen's comment; Don't use a cat. Speaking from experience, they can blow up switchgear just as easily as can a lizard or a small rodent. Follow Moses Wakatama's recommendation instead. Find ways to keep the small animals away from your high voltage systems. Use whatever means is appropriate; traps, poisons, physical barriers, automatic sprayers to kill insects that attract lizards etc.

well, from the point of view of lizards, it's the substation a big danger for them

No mention so far of two-legged vermin!
EU standards at least should exclude vermin from metal-clad switchgear if no covers are left off.
Wildlife more of a problem with outdoor gear. Nesting on cross arms , or wingspans that bridge two phases!

It looks like the problem is related to the nuisances of the lizard droppings and laying eggs in whatever gaps they can find.

Switch off the lights in the unmanned substations whenever people leave the rooms. Lizards feed on the insects attracted by the lights at night. I had done it before and found the lizards bodies around, starved to dead I think.

If flashover in the 11kV switchgear was caused by the lizards, continue to do the vermin proving works on the switchgear enclosures. You haven't complete the task yet.

One has to live with these animals without frustration. Case to case maint. person has to put efforts continuously to protect equipments. Follow Mr. Mosses. You won't get one time solution, to be alert all the time and take steps as required.

Here in North East USA, we use animal guards...our company usually buys plastic ones..the y are shaped like the object they are intended to keep rodents, bees etc away from and the 2 pieces easily snap together to form a sealed enclosure for say a transformer bushing etc. Another animal guard which has an open design is called Guthrie Gaurd...it is made of metal and it works buy giving a small zap to animals (inductance from phase wire) to deter them.