Abstract:
This project develops an automatic tripping mechanism for the three phase supply
system. The project output resets automatically after a brief interruption in the
event temporary fault while it remains in tripped condition in case of permanent
fault.
The electrical substation which supply the power to the consumers, have failures
due to some faults which can be temporary or permanent. These faults lead to
substantial damage to the power system equipment. In India it is common, The
faults might be LG (Line to Ground), LL (Line to Line), 3L (Three lines)in the
supply systems and these faults in three phase supply system can affect the power
system. To overcome this problem a system is built, which can sense these faults
and automatically disconnects the supply to avoid large scale damage to the control
gears in the grid sub-stations.
This system is built using three single phase transformers which are wired in star
input and star output, and 3 transformers are connected in delta connections, having
input 220 volt and output at 12 volt. This concept low voltage testing of fault
conditions is followed as it is not advisable to create on mains line. 555 timers are
used for handling short duration and long duration fault conditions. A set of
switches are used to create the LL, LG and 3L fault in low voltage side, for
activating the tripping mechanism. Short duration fault returns the supply to the
load immediately called as temporary trip while long duration shall result in
permanent trip.
The concept in the future can be extended to developing a mechanism to send
message to the authorities via SMS by interfacing a GSM modem.
