Use the grounding line selection device and fault indicator to find

Substation is generally installed grounding line selection device,although sometimes not,but can

provide technical reference for artificial switch.Then install on the road online some earth fault indicator (or short circuit grounding combined fault indicator),make clear ground fault.Reliable grounding fault detection method is using the method of signal source,more sensitive ground fault detection method is to use the first half wave method or the dc transient analysis.Recommended two kinds of grounding fault indicator method to find the combination of fault is better,by the method of signal source is given priority to,in the first half wave method or the dc transient analysis is complementary.Using the method to find the feeder automation If the user is rich,the recommended method for grounding fault feeder automation.The method USES intelligent switch (electric load

switch,sectionalizer,circuit breaker,the reclosing + FTU) logic functions instead of traditional

artificial search method,and can automatically realize the fault isolation,recovery and transfer

power supply.

Assuming a dual power supply circuit is divided into 6 segments,hand in hand with 5

intelligent switch (double side with five pillar type brake rotor three-phase signal PT or capacitive

PT),contact the middle one,and the ground fault point between the first and second intelligent switch as an example,the concrete implementation steps are as follows: Will (1) substation grounding wire switch power,the line on each section of intelligent switch points brake automatically.2 substation switching power,power station zero sequence voltage alarm,restore the section 6;The first intelligent switch FTU line voltage is detected,but there is no zero sequence voltage is detected,the delay time automatic switching,due to close to the ground fault detection to zero sequence voltage,break-brake immediately and "locked-in";Second intelligent switch and zero sequence voltage is detected,the switch and "blocking",cancel the "electric automatic switching delay" function.(3) intermediate to unilateral loss of electric contact switch detection,delay for a period of time after the automatic www.facebook.com/guohong.trading switching,due to the fault point is not that section,no zero sequence voltage is detected,the segment transfer power to succeed.Intelligent switch (4) contact switch electric transmission,second line voltage is detected,no zero sequence voltage is detected,but a "lock" in generator rotor and stator the former,cancelled "electricity function of automatic switching" switch in points.5] at this point,the ground fault point section has been separated,the fault section has been restored or other transfer of power supply.