Regarding to Gas Turbine ESD HH Low Frequency Pulsation of GTG

Dear Sirs,
Dated on 10.11.2019 05:48pm there were emergency shutdown at one time of the Gas turbine generators GTG-B and GTG-C due to the signal “ESD Low frequency pulsation external fault”.

After investigating the emergency shutdown of GTG-B and GTG-C, it was revealed that a short circuit with ground occurred on the phase “C” of a 35kV power cable with a cross section of 240 mm2 at the connection point of the power transformer A30-TMM-201A HDPE plant.

We have question if happened one phase short circuit with the ground on the power cable 35kV another outgoing feeder why at one time happened emergency shutdown Gas turbine generators  GTG-B and GTG-C from the signal "GT ESD Low frequency pulsation external fault” 
In connection withabovementioned, could you please investigate and give to us recommendation for solving this problem.This problem till today happened 4-times.
if you have any questions or and want additional information let me us.
best regards,
Mambetnazarov Akhmed
Head of Electrical Engineer of company Uz-Kor 

Can you share a possible schematic layout? Thanks

Yes, see attached files. Thank you in advance. If you have any question please let me know.

Can you share the documents via Dropbox or elsewhere, they are not clear?

I was just thinking of a long X shape with 4 photocells at one end in a bridge, driving 2 motors directly. I suppose that would be too simple? <grin>

It is not X shape with 4 photocells, this is Bently Nevada device for measuring  Frequency Pulsation of Flame in the Gas Turbine. And also Mr. Alan Gallagher can you give me your e-mail address for sending detail drawing.    

It's what??