A kind of online line fault monitoring and protective device
Technical field
The utility model relates to a kind of online line fault monitoring and protective device.
Background technology
At present, the neutral operation method of electric power system has two large types, and one is directly grounded ground current system, is separately earth-free or through the small grounding current system of grounding through arc or resistance grounded.
Above two kinds of systems are because earthing mode is different, and operation characteristic is also thereupon different: the former can produce very large short circuit current when system's generation single-phase earthing, and does not allow the operation for a long time in system of single-phase fault point; Earth-free or compensated distribution network, when system's generation single-phase earthing, the earth current that produces is not very large, capacitive earth current for system, simultaneity factor line voltage preserved symmetry does not affect user's normal electricity consumption, so allow single-phase earthing point long-play in system, can reduce the system blackout number of times, improve power supply reliability.
Just because of small grounding current system has the characteristic of moving with single-phase earthing point for a long time, showed the good one side to user's uninterrupted power supply, thereby obtained general propagation and employment in the electrical network of 3.3kV, 6kV, 10kV, 35kV, 66kV.But due to the protective capability of system's shortage to single phase ground fault, there are many weak points in the runnability of system, is mainly manifested in following seven aspects:
(1) to extinguish the ground arc ability low in system.
(2) compensated distribution network is subjected to arc suppression coil entirely to compensate the restriction of resonance overvoltage, and earth point still has residual flow, and ground arc is still existed.
(3) if personal single-phase electrification occurs, uninterruptedly to the earth point power supply, make the electrification personnel can not break away from fast power supply due to system, under the long duration of action of system's capacitive earth current, can cause personal injury accident.
(4) if ground connection is intermittent, again can the initiating system overvoltage, the accident of burning electric equipment.
(5) the GIS combined electrical apparatus is inner when single-phase earthing occurs, if find untimelyly, electric arc is at inner burned for long time, and casing can produce very large pressure, and its consequence is very fearful.
(6) system of Neutral Grounding through Resistance in Electrical, when system's generation single-phase earthing, control is flow through the electric current of earth point in the 500A left and right, and what also have is controlled at about 100A.Start the zero-sequenceprotection action by the electric current that flows through earth point, the excision faulty line.No matter be permanent or volatile, all act on tripping operation, the tripping operation number of times of circuit is increased greatly, had a strong impact on user's normal power supply, its power supply reliability is descended.
(7) general supply line more complicated, searching of fault point is more difficult, and fault is got rid of need to expend a large amount of human resources, and can not promptly and accurately find the fault point.
Summary of the invention
For addressing the above problem; the purpose of this utility model is to provide a kind of online line fault monitoring and protective device; adopt effective connection of phase-splitting circuit breaker, Low ESR reactor, current transformer; can find out fast the fault point; when guaranteeing maintenance personal's personal safety; greatly improve fault removal efficiency, guaranteed resident's normal electricity consumption.
The utility model is the purpose that reaches above-mentioned, and the utility model adopts following technical scheme:
A kind of online line fault monitoring and protective device comprise the phase-splitting circuit breaker, and described phase-splitting circuit breaker is connected with isolating switch, and isolating switch is connected with substation bus bar, and described substation bus bar is connected with the PT cabinet; Described phase-splitting circuit breaker is connected with Low ESR reactor, ground protection control unit respectively, and described Low ESR reactor is connected with current transformer, and current transformer is connected with the first ground network; Described ground protection control unit is connected with Low ESR reactor, current transformer, PT cabinet respectively; Described substation bus bar is connected with the second ground network.
Described ground protection control unit adopts the single-chip microcomputer of many CPU.
The beneficial effects of the utility model are: the utility model provides a kind of online line fault monitoring and protective device; adopt effective connection of phase-splitting circuit breaker, Low ESR reactor, current transformer; can find out fast the fault point; when guaranteeing maintenance personal's personal safety; greatly improve fault removal efficiency, guaranteed resident's normal electricity consumption.
Description of drawings
Fig. 1 is structural representation of the present utility model.
Embodiment
Embodiment 1
As shown in Figure 1, the present embodiment provides a kind of online line fault monitoring and protective device, comprises phase-splitting circuit breaker 4, and described phase-splitting circuit breaker 4 is connected with isolating switch 3, and isolating switch 3 is connected with substation bus bar 2, and described substation bus bar 2 is connected with PT cabinet 9; Described phase-splitting circuit breaker 4 is connected with Low ESR reactor 5, ground protection control unit 1 respectively, and described Low ESR reactor 5 is connected with current transformer 6, and current transformer 6 is connected with the first ground network 7; Described ground protection control unit 1 is connected with Low ESR reactor 5, current transformer 6, PT cabinet 9 respectively; Described substation bus bar 2 is connected with the second ground network 8.Described ground protection control unit 1 adopts the single-chip microcomputer of many CPU.
The described a kind of online line fault monitoring of the present embodiment with the guard method of protective device is: at first ground protection control unit 1 gathers the voltage of substation bus bar 2 by PT cabinet 9, and ground protection control unit 1 gathers the electric current of current transformer 6 simultaneously; Then gather the three-phase of substation bus bar 2 according to ground protection control unit 1, line and residual voltage value, by the computing system three-phase, the amplitude of line and residual voltage and the variation of angle each other judge whether system single phase ground fault occurs; When ground protection control unit 1 judges system's generation single phase ground fault, ground protection control unit 1 closes a floodgate the control that phase-splitting circuit breaker 4 breaks down mutually, reduces its earth current thereby the single phase ground fault electric wire occurs after closing a floodgate by Low ESR reactor 5, the first ground network 7; After earth fault was got rid of, ground protection control unit 1 made 4 each controls of phase-splitting circuit breaker keep mutually off-state, and whole circuit is proceeded monitoring.
A kind of online line fault monitoring and the protective device of the present embodiment manufacturing; adopt effective connection of phase-splitting circuit breaker, Low ESR reactor, current transformer; can find out fast the fault point; when guaranteeing maintenance personal's personal safety; greatly improve fault removal efficiency, guaranteed resident's normal electricity consumption.