Direct current injection type route selecting positioning system and method thereof
A positioning system, DC injection technology, applied in fault locations, emergency protection circuit devices for limiting overcurrent/overvoltage, instruments, etc., can solve the problems of high technical requirements and easy interference of injection signal detection devices, Achieve the effect of satisfying detection sensitivity and improving accuracy
A positioning system, DC injection technology, applied in fault locations, emergency protection circuit devices for limiting overcurrent/overvoltage, instruments, etc., can solve the problems of high technical requirements and easy interference of injection signal detection devices, Achieve the effect of satisfying detection sensitivity and improving accuracy
CN101303387AInactive Publication Date: 2008-11-12中国石油化工股份有限公司胜利油田分公司临盘采油厂 +1
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Embodiment 1
[0037] In a substation of an oil production plant, a grounding test was carried out on the principle of DC injection line selection and positioning for high transition resistance, and the records are shown in Table 1.
[0038] It can be seen from Table 1 that when the transition resistance is high, the injected DC current flowing through the fault point is relatively large, which can meet the detection accuracy requirements of the fault indicator. With the increase of the transition resistance, the injected direct current flowing through the fault point decreases, but it can also meet the detection sensitivity requirements.
[0039] It can also be seen from Table 1 that when the current-limiting resistor connected in series with the DC current generator changes, it will affect the size of the injected DC current. The resistance plays the role of adjusting the magnitude of the injected DC current, but when the transition resistance is constant, it has little effect on the DC cu...
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The invention discloses a DC injection type route selection positioning system and a method thereof, which makes use of neutral-point voltage to ground to provide power supply for the generation of DC signal and inject DC to a fault system, and realizes faulty route selection and position by the detection of circulation of the DC signals. The structure of the invention comprises a grounding transformer, a DC generator, a control device and a fault indicator FD, wherein, the grounding transformer is connected with a system bus and injects the DC to the fault system by the primary coil of the grounding transformer; the DC generator is arranged between the primary-side neutral-point N of the grounding transformer and the ground; the control device is connected with the secondary side of bus-bar potential transformer to monitor whether a power distribution system has single-phase earth fault, control the switching of the DC, measure the injected DC at the same time and adjust the injected DC according to the measured injected DC; the fault indicator FD is positioned at the outlet of each feeder, and the fault indicator FD is also arranged at the feeder at intervals to detect the injected DC and select faulty line and locate the fault.
Description
technical field [0001] The invention relates to a ground fault detection technology in a distribution network of a power system, in particular to a DC injection type line selection and positioning system and a method thereof for a neutral point ungrounded or arc suppressing coil grounded system. Background technique [0002] In my country, for the distribution network currently in operation, since the neutral point of the system is not grounded or grounded through the arc suppression coil, no short-circuit loop will be formed after a single-phase ground fault occurs, and only a small zero-sequence current caused by the distributed capacitance of the system. Various devices for finding single-phase ground faults at home and abroad are based on these relatively small faults as the judgment basis, and the misjudgment rate is relatively high. When the distribution network is in normal operation, the three-phase voltage is symmetrical, and the voltage between the neutral point an...
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Patent Timeline
12 Nov 2008
Publication
CN101303387A
- IPC
- G01R31/08; G01R31/00; H02H9/08
- Inventors
- 高志鹏; 张慧芬