Beijing Tianyihongda Science & Technology Development Co., LTD |
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Brief Introduction
TYHD-AI/110 OverheadLine smart power
line Fault Indicator is applied to 110kV overhead line ,is a
device to indicate line fault current. This system is composed of
two parts, one is gathering unit and the other is collection
unit.gathering unit monitors line running status real-time. When
fault happened ,the gathering unit can quickly locate phase-phase
short-circuit area,the fault line and fault point can be judged
quickly and accurately.in the meantime, the alarm flag turn red and
appear flashlight and the fault signal also be transmitted to
collection unit. After receiving signal from gathering unit, the
collection unit send the received data to master monitoring station
through wireless communication (GPRS/CDMA etc.).
The master station monitoring software
analyze the received data and network topology, then to confirm the
fault location and appear audible and visual alarm signal, in the
meantime, the master station send the analyzed fault information to
the operator’s cellphone and help them to find the fault point
quickly, it reduces the power-off duration and improve the power
supply reliability. Note: gathering unit is named fault indicator and collection unit is DTU
originally.
The fault indicator’s gathering unit uses gripping structure and
coil to induct line current and electrical field signal, these
signals are gathered and dealt with through low power consumption
single-chip and finish the line load current
calculation&short-circuit detection and realize short-distance
wireless communication through inner-equipped wireless module with
low power consumption,then send the signals to collection unit.
When gathering unit detects that the line current is corresponds to
short-circuit characteristics, it immediately transmit the fault
information to collection unit nearby through wireless module, in
the meantime, alarm appears in means of red flag and flashlight,
the collection unit receives every kind of signals then real-time
transmit them to the master station monitoring platform through
remote wireless communication, the master station will complete the
data analysis and fault judgement.
Device application principle is as following diagram:
communicable fault indicator application principle
Short-circuit detection adopts load current self-adaption intelligent sudden changes method. According to the characteristics of short-circuit, it judges the fault through electromagnetic inductive method to detect the sudden changed current in line and sudden changed current duration,it is a kind of fault detection device which automatically adapts to load current changes and only related with short-circuit current component.The short-circuit detection principle is that the line current will change as the following diagram when fault happen
(3) Line is powered off, the line current and voltage is decreased
to zero.
According to this characteristic, the short-circuit detection
criteria of self-adaption short-circuit fault indicator can be
summarized as following
(1) △IF>Iset
(2) T1<△T<T2
(3) IH=0,UH=0
In the above, △IF is fault current component or current variable
quantity, Iset is interior default value, there is a little
difference for different type of indicator installed in different
site.△T is fault lasting time,T1,T2 are interior default value,it
is determined by system’s protection and switch performance; T1 is
the fastest time that the fault is cleared,T2 is the most possible
longest duration required for fault clearance ,IH,UH are current
and voltage value after fault.the above judgment criteria can be
described as: when line current gets a positive sudden change,its
changed quantity is above a certain setting value, then the current
and voltage decreased to zero in a short time, then the line
current is judged as fault current. Obviously, it is only related
with short-circuit current component when fault happen and there is
not direct relation with line current value in normal working
status. So it is a fault detection device which can adapt to load
current changes. Its judgement criteria is comparatively complete
and can largely reduce the possiblity of mis-alarm.