How to monitor 3 phase line (phase failure)?

Hi,

We need to design the phase detector circuit. We need to monitor the 3 phase line(230v ac,50Hz) for phase failure or phase change and send the status to microcontroller. Iam new to this. Please suggest me, how to build this circuit.

(I need to detect an OPEN Phase or phase to phase SHORT fault on 3 Phase supply input. If I detect any of following faults i need to send status signal to microcontroller.
OPEN Phase – A
OPEN Phase – B
OPEN Phase – C
Phase A to B Short
Phase B to C Short
Phase C to A Short )

Regards,
Naveen K

Hello!
Yes the best way of this ,Make a small MCU makes these functions:
1- detect the rising edge on Line "A" normally called "R" and start Timer
2- then detect the rising edge on Line "B" normally called "S"
3- then detect the rising edge on Line "C" normally called "T"

usualy we detect the time between two edges on the line R
It must be 20mS for 50Hz network ~16.7ms for 60Hz network
then divide this time on 3
then check the time to rise an edge on phase "S" or "T" t12
if t12 =~ T/3 then the squential R S T is correct
if t12 = ~ 2T/3 then the squential R S T is incorrect

if t12 = ~ T then invalid network and there is a short circuit


good luck