1 summarize

TYHD-AI2 fault passage indicator is installed on the overhead power lines for 6KV-35KV, is to detect and locate the grounded fault and short circuit fault for overhead line. It will alarm (red flag and flashlight) during the day and flash during night to show the fault. According to the alarm information , the operator can locate the fault area quickly and find out the point of fault, which supply the best solution for the difficulty in finding fault area. This device can improve work efficiency, reduce power outage time and power restoration quickly.The installation and uninstalling way is very simple and convenient. The battery can be changed if clients requires battery replacement. parameters can be customized by clients requirement.

2 Short circuit detection principles:

Short-circuit adopts method of load current self-adaption intelligent sudden changing way. According to the characteristics of short-circuit, the indicator detects sudden changing current and its lasting time in line to judge fault through electro-magnetic induction way. It is a fault detection device which can automatically adapt to load current changes and only related with short-circuit current component when fault happen. The judgement principle for short-circuit is as following:

Instruction:When short-circuit happen in line, the fault current passage is from fault point to substation,all indicators which the fault current flows through will sense the current sudden changes.with the switch tripped at exit of substation, the line will be in status of loss of voltage and current. Then indicator judge the line power off and the changing characteristics of line voltage and current meet the indicator’s short-circuit judgement criteria and will alarm to red flag and flashlight to indicate.

From the above we can see, When short circuit fault occurs in lines, the indicators will sense the fault current and the display window of fault passage indicator will turn from white into red (or from normal to flashlight). according to the line 2# phase B indicator 2,5,8and line3# phase C indicator 3,6,9 red flag alarm(or flashlight)but indicator 11,12 do not alarm (or no flashlight),we can quickly confirm D is the fault point.

3 earthed detection principle:

earthed fault detection principle adopts intelligent transient status method: Through detection the changing characteristics of transient current and the transient voltage at the instant of earthing to judge earth fault.

The indicator judges it as earthed fault as following condition: Through sampling the capacitive current first half-wave and voltage first half-wave at the instant of earthing fault, then compare the phase position, when sampling the earthed transient capacitive current sudden changed and it is higher than a certain value, moreover, the first half-wave of sampling the earthed transient capacitive current is contrast to the earthed transient voltage and also the line voltage to ground decreased, then the indicator will judge earth fault happened, or else, it will not be judged as earth fault.

Compared with capacitive current pulse amplitude method, this method don’t need to configure threshold value. For any structure of power supply network,when single-phase earth fault happen, the capacitive current first half-wave in the fault section is contrast to earthed transient voltage, and then non-fault line and the capacitive current first half-wave in latter section after fault area are the same phase with the earthed transient voltage, this rule is applied to any kind of earthed fault. So this principle for detection of earth fault accuracy will be improved a lot.

fault indication principle to judge earth fault

Instruction: After earth fault happened,the earthed phase electrical field is decreased, in the meantime, the earthed current first half-wave generated by the earthed phase from earthed point to substation is contrast to the voltage phase position, and the earthed current first-half wave of the following part after earthed point is same with voltage phase position, so the changing characteristics of the earthed phase electrical field and earthed current transient changes characteristics between fault point former part and substation conform to indicator alarm condition. From diagram above, line 2# phase C 3,6,9 indicator alarm by red flag or flashlight. But indicator12 still in white, we can judge the earthed fault is in point D.

4 basic function

• fault indication: The window appears white when line running normally;when short-circuit and earth fault happen, the window will appear red and flashlight at meantime.
• Power taking function:Taking power from line through magnetic ring and not consume stand-by battery, extend indicator life, the stand-by battery can be replaced.
• running online.installed on overhead line directly,free-maintenance.
• Good adaptability: The accuracy of fault detection will not be affected by the load current changing value
• strong anti-disturbance capacity:Signal is not affected by line,magnetizing rush current,ultra-harmonics and current wave,especially the earthed capacitance current under condition of mixed lines
• intelligent reset:
  • permanent fault:fault is cleared and power is restored, fault passage indicator will reset for short time；
  • Transient fault:Line fault happened and tripped then re-close successfully, fault passage indicator will reset by setting time.

• oltage applicable: 10kV-35KV
• line power-taking capacity: not consume stand-by battery power when line load current is above 10A
• long withstand current: 630A
• protection grade: IP68
• line diameter applicable: 16mm²≤d≤400mm²

• install and uninstall with power:can be installed and uninstalled when line is on power,not affect line running status.
• Alarm response time: 0.02S≤T≤3S
• Static power consumption: ≤20μA
• reset time: 6,12,24,48 hours,can be defined by client oneself.
• Ambient temperature: －40℃≤T≤+75℃
• Alarm times: ≥2000 times
• Led flash hours: 10000hours
• weight: ≤500g
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• For more device details, please contact our company mail:bjxrqfoverseas@163.com.  we can do by clients's inquirement for different parameters. 
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