At the risk of walking a weak limb, here, I suggest you might be surprised at how little "near field" induction occurs because of nearby power lines. I'm surrounded by them. It's not generally the 'power lines' that cause issues... its things attached to them... but then if you detect an 'arcing' transformer or insulator, the utility company would love to know it. Vacuum cleaners, drills, furnace/AC motors.. that kind of thing... aging or failing 'vapor' street lights, etc... plasma TV's... the truck axle plant over the hill and its welding lines.... 
most issues are caused by other things....
Nearby flashes, in the distance range you mention, seem to be a bit more difficult to reconcile, because of their strength (distortion) and the fact that frequent discharges and constant 'sferics' may well send the system into 'interference' mode... that's where the rest of the network takes over, and records the sferic... a good operating system might operate most effectively in the range of 50-500 miles most effectively, going 'interference' for e.g. with cells <50 miles...
There are a lot of variables, here.. but in effect the developers have produced an excellent system, up through the currently operating "Red" systems... and once properly optimized and located, they can operate in and around power lines,. Must remember, this is NOT a "plug 'n' play" device... it requires some background knowledge, a small bit of research, and experimentation, for operators...
There are some indications that further 'developments' in any upcoming hardware may be even more efficient and simpler, coupled with the more advanced processing and 'fingerprinting' of the signals on the server side. Remember that the 'local' systems do not detect 'lightning'... just various signature signals... the 'server' determines if it was a flash, once it is received...
As far as a microphone to calibrate 'thunder' speed...while very interesting, and possibly viable... we might consider that a bit of a 'gimmick', extra feature... and Tobi had quite a brainstorm creating it... actually it is reasonably accurate in many cases... but, trust me, any 'thunder' representations are very, very, far down on the list of priorities... if it's even on the list! Locating and characterizing parameters of strokes is the top priority.
Do you plan to install a station when systems again available???
Mike
most issues are caused by other things....
Nearby flashes, in the distance range you mention, seem to be a bit more difficult to reconcile, because of their strength (distortion) and the fact that frequent discharges and constant 'sferics' may well send the system into 'interference' mode... that's where the rest of the network takes over, and records the sferic... a good operating system might operate most effectively in the range of 50-500 miles most effectively, going 'interference' for e.g. with cells <50 miles...
There are a lot of variables, here.. but in effect the developers have produced an excellent system, up through the currently operating "Red" systems... and once properly optimized and located, they can operate in and around power lines,. Must remember, this is NOT a "plug 'n' play" device... it requires some background knowledge, a small bit of research, and experimentation, for operators...
There are some indications that further 'developments' in any upcoming hardware may be even more efficient and simpler, coupled with the more advanced processing and 'fingerprinting' of the signals on the server side. Remember that the 'local' systems do not detect 'lightning'... just various signature signals... the 'server' determines if it was a flash, once it is received...
As far as a microphone to calibrate 'thunder' speed...while very interesting, and possibly viable... we might consider that a bit of a 'gimmick', extra feature... and Tobi had quite a brainstorm creating it... actually it is reasonably accurate in many cases... but, trust me, any 'thunder' representations are very, very, far down on the list of priorities... if it's even on the list! Locating and characterizing parameters of strokes is the top priority.
Do you plan to install a station when systems again available???
Mike
