CN212410752U - Low-voltage distribution line ground fault detector - Google Patents
Low-voltage distribution line ground fault detector Download PDFInfo
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- CN212410752U CN212410752U CN202020813191.4U CN202020813191U CN212410752U CN 212410752 U CN212410752 U CN 212410752U CN 202020813191 U CN202020813191 U CN 202020813191U CN 212410752 U CN212410752 U CN 212410752U
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Abstract
The utility model discloses a low pressure distribution lines ground fault detector, including zero sequence current transformer, a first opening CT for gathering the current signal of A phase match electric wire, a second opening CT for gathering the current signal of B phase match electric wire, a third opening CT for gathering the current signal of C phase match electric wire, a fourth opening CT for gathering the current signal of zero line, a first binding post for inputing the current signal that four opening CT gathered to zero sequence current transformer respectively, a multiplying power ampere meter for receiving zero sequence current transformer output current and showing the current value, and a first warning circuit for receiving zero sequence current transformer output current, and send alarm signal when zero sequence current transformer output current is greater than the default; the leakage current value is directly read out through the ammeter with multiplying power, the vector sum of the currents of the four wires does not need to be calculated by a calculating unit to obtain zero sequence current, and the leakage current measuring device is simple in structure and low in cost.
Description
Technical Field
The utility model relates to an electrical instrument field, concretely relates to low pressure distribution lines earth fault detector.
Background
The ground fault of the urban low-voltage power grid occurs frequently, and the normal power utilization of users is influenced. Due to the existence of the grounding leakage current, the low voltage and high loss conditions of the transformer area are caused, and the indexes of the transformer area are influenced. At present, a line protection grounding line selection device of a southern low-voltage power grid is only assembled on a 10kV line, and monitoring and protection such as electric leakage, overvoltage and the like are only assembled in a transformer distribution box, and the current and voltage of a branch line are not monitored. Therefore, the grounding fault point cannot be found out in time under the condition that the three-phase four-wire distribution line has the grounding fault, and the problem of the current distribution maintenance work is solved. In the prior art, the leakage fault detection equipment has a complex structure, is inconvenient to carry and can detect fault points in time, so that a low-voltage distribution line ground fault detector with a simple structure is urgently needed.
SUMMERY OF THE UTILITY MODEL
The utility model mainly aims at providing a simple structure's low pressure distribution lines earth fault detector.
In order to achieve the above object, the utility model provides a low voltage distribution lines ground fault detector, including zero sequence current transformer, be used for gathering the first opening CT of the current signal of A phase matching electric wire, be used for gathering the second opening CT of the current signal of B phase matching electric wire, be used for gathering the third opening CT of the current signal of C phase matching electric wire, be used for gathering the fourth opening CT of the current signal of zero line, be used for with four the current signal that opening CT gathered input respectively to zero sequence current transformer's first binding post, be used for receiving zero sequence current transformer output current and show the multiplying power ampere meter of current value, and be used for receiving zero sequence current transformer output current, and send alarm signal's first alarm circuit when zero sequence current transformer output current is greater than the default;
the signal output end of the opening CT is connected with four signal input ends in the first wiring terminal in a one-to-one correspondence mode, the signal output end of the first wiring terminal is connected with the signal input end of the zero sequence current transformer, the signal output end of the zero sequence current transformer is electrically connected with the signal input end of the multiplying power ampere meter, and the signal output end of the zero sequence current transformer is electrically connected with the alarm circuit.
Preferably, the ground fault detector further comprises three groups of single-phase voltage detectors, a ground down conductor for grounding the three groups of single-phase voltage detectors, three wire clamps for respectively collecting voltage signals between the phase a, the phase B and the phase C relative to the ground, second connecting terminals for respectively inputting the voltage signals collected by the three wire clamps to the three groups of single-phase voltage detectors, and a second alarm circuit for receiving the output voltage of the three groups of single-phase voltage detectors and starting an alarm when the output voltage of the single-phase voltage detectors is smaller than a preset value;
the signal output end of the wire clamp is respectively and correspondingly electrically connected with the signal input end of the second wiring terminal, the signal output end of each second wiring terminal is respectively and electrically connected with the signal input ends of the three groups of single-phase voltage detectors, the signal output ends of the single-phase voltage detectors are electrically connected with the grounding down lead, and the signal output ends of the three groups of single-phase voltage detectors are all connected in series with the second alarm circuit to be used for disconnecting or connecting the second alarm circuit.
Preferably, the first alarm circuit comprises a switching power supply and an alarm bell, which form an alarm loop, and a current relay arranged in the alarm loop, wherein an input end of the current relay is electrically connected with a signal output end of the zero sequence current transformer, and an output end of the current relay is electrically connected with the alarm loop for disconnecting or connecting the alarm loop.
Preferably, the second alarm circuit includes a first signal lamp, a second signal lamp, a third signal lamp and the switching power supply, an input end of the first signal lamp is electrically connected to an output end of the single-phase voltage detector corresponding to a, an input end of the second signal lamp is electrically connected to an output end of the single-phase voltage detector corresponding to B, an input end of the third signal lamp is electrically connected to an output end of the single-phase voltage detector corresponding to C, and output ends of the first signal lamp, the second signal lamp and the third signal lamp are all electrically connected to the switching power supply.
Preferably, the first connection terminal is an eight-core double-plug connection terminal.
Preferably, the second connecting terminal is a three-core double-plug connecting terminal.
Preferably, the ground fault detector further includes a housing, and the zero sequence current transformer, the current relay, the switching power supply, the three groups of single-phase voltage detectors, and the switching power supply are all disposed inside the housing; the multiplying power ammeter, the first signal lamp, the second signal lamp, the third signal and the alarm bell are all arranged on the surface of the shell.
Preferably, the ground fault detector further comprises a wire collecting box and a handle, wherein the wire collecting box is arranged at one end, close to the opening CT, of the shell, and the handle is arranged at one end, far away from the wire collecting box, of the shell.
Preferably, the ground fault detector further comprises a wireless communication module for communicating with an upper computer.
The technical scheme of the utility model, opening CT's signal output part with four signal input end one-to-one in the first binding post are connected, through zero sequence current transformer measures zero sequence current value, and the zero sequence current value that obtains multiplies opening CT's mutual inductance ratio, multiply again zero sequence current transformer's mutual inductance ratio is leakage current value once for the circuit, through the ampere meter that has the multiplying power direct readout leakage current value, need not calculate the vector of four wire currents with the calculating unit and obtain zero sequence current, has left out the calculation module component, simple structure, and is with low costs. Meanwhile, the first alarm circuit sends out an alarm signal when the output current of the zero sequence current transformer is larger than a preset value, so that the quick positioning of the ground fault is realized, and the positioning efficiency of the fault is greatly improved. The grounding fault detector is convenient to operate, a power distributor is connected with the four opening CTs in a hanging mode, and the detection of the grounding fault of the low-voltage power grid can be achieved on the ground by sampling the current.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a detector according to an embodiment of the present invention.
Fig. 2 is a schematic circuit diagram of the detector shown in fig. 1 according to the embodiment.
Fig. 3 is a schematic circuit diagram of the current monitoring circuit of fig. 2.
Fig. 4 is a schematic circuit diagram of the voltage-ground line selection circuit in fig. 2.
The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In addition, descriptions in the present application as to "first", "second", and the like are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the present application, unless expressly stated or limited otherwise, the terms "connected" and "fixed" are to be construed broadly, e.g., "fixed" may be fixedly connected or detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
In addition, the technical solutions between the embodiments of the present invention can be combined with each other, but it is necessary to be able to be realized by a person having ordinary skill in the art as a basis, and when the technical solutions are contradictory or cannot be realized, the combination of such technical solutions should be considered to be absent, and is not within the protection scope of the present invention.
The utility model provides a low pressure distribution lines earth fault detector.
As shown in fig. 1 to 4, the low-voltage distribution line ground fault detector disclosed in this embodiment includes a zero sequence current transformer, a first opening CT for collecting a current signal of an a-phase matching wire, a second opening CT for collecting a current signal of a B-phase matching wire, a third opening CT for collecting a current signal of a C-phase matching wire, a fourth opening CT for collecting a current signal of a zero line, a first connection terminal for respectively inputting the current signals collected by the four opening CTs to the zero sequence current transformer, a multiplying power ammeter for receiving an output current of the zero sequence current transformer and displaying a current value, and a first alarm circuit for receiving the output current of the zero sequence current transformer and sending an alarm signal when the output current of the zero sequence current transformer is greater than a preset value;
the signal output end of the opening CT is connected with four signal input ends in the first wiring terminal in a one-to-one correspondence mode, the signal output end of the first wiring terminal is connected with the signal input end of the zero sequence current transformer, the signal output end of the zero sequence current transformer is electrically connected with the signal input end of the multiplying power ampere meter, and the signal output end of the zero sequence current transformer is electrically connected with the alarm circuit.
The technical scheme of the utility model, opening CT's signal output part with four signal input end one-to-one in the first binding post are connected, through zero sequence current transformer measures zero sequence current value, and the zero sequence current value that obtains multiplies opening CT's mutual inductance ratio, multiply again zero sequence current transformer's mutual inductance ratio is leakage current value once for the circuit, through the ampere meter that has the multiplying power direct readout leakage current value, need not calculate the vector of four wire currents with the calculating unit and obtain zero sequence current, has left out the calculation module component, simple structure, and is with low costs. Meanwhile, the first alarm circuit sends out an alarm signal when the output current of the zero sequence current transformer is larger than a preset value, so that the quick positioning of the ground fault is realized, and the positioning efficiency of the fault is greatly improved. The grounding fault detector is convenient to operate, a power distributor is connected with the four opening CTs in a hanging mode, and the detection of the grounding fault of the low-voltage power grid can be achieved on the ground by sampling the current.
Specifically, the signal output end of the opening CT is connected with four signal input ends in the first wiring terminal in a one-to-one correspondence manner, which means that: first opening CT signal output part with first signal input part electricity in the first binding post is connected, second opening CT signal output part with second signal input part electricity in the first binding post is connected, third opening CT signal output part with third signal input part electricity in the first binding post is connected, fourth opening CT signal output part with fourth signal input part electricity in the first binding post is connected.
Preferably, the ground fault detector further comprises three groups of single-phase voltage detectors, a ground down conductor for grounding the three groups of single-phase voltage detectors, three wire clamps for respectively collecting voltage signals between the phase a, the phase B and the phase C relative to the ground, second connecting terminals for respectively inputting the voltage signals collected by the three wire clamps to the three groups of single-phase voltage detectors, and a second alarm circuit for receiving the output voltage of the three groups of single-phase voltage detectors and starting an alarm when the output voltage of the single-phase voltage detectors is smaller than a preset value;
the signal output end of the wire clamp is respectively and correspondingly electrically connected with the signal input end of the second wiring terminal, the signal output end of each second wiring terminal is respectively and electrically connected with the signal input ends of the three groups of single-phase voltage detectors, the signal output ends of the single-phase voltage detectors are electrically connected with the grounding down lead, and the signal output ends of the three groups of single-phase voltage detectors are all connected in series with the second alarm circuit to be used for disconnecting or connecting the second alarm circuit.
Specifically, the single-phase voltage detector is a voltage relay, an auxiliary contact of the voltage relay is electrically connected with the second alarm circuit, the circuit works normally, the detected voltage is normal, the auxiliary contact is in an off state, and when the detected phase has a ground fault and the voltage is insufficient, the auxiliary contact is in a closed state and the second alarm circuit is switched on.
Preferably, the first alarm circuit comprises a switching power supply and an alarm bell, which form an alarm loop, and a current relay arranged in the alarm loop, wherein an input end of the current relay is electrically connected with a signal output end of the zero sequence current transformer, and an output end of the current relay is electrically connected with the alarm loop for disconnecting or connecting the alarm loop.
Specifically, when the current output by the zero sequence current transformer is greater than a preset value, the auxiliary contact of the current relay closes the alarm circuit, and the alarm bell is started.
Preferably, the second alarm circuit includes a first signal lamp, a second signal lamp, a third signal lamp and the switching power supply, an input end of the first signal lamp is electrically connected to an output end of the single-phase voltage detector corresponding to a, an input end of the second signal lamp is electrically connected to an output end of the single-phase voltage detector corresponding to B, an input end of the third signal lamp is electrically connected to an output end of the single-phase voltage detector corresponding to C, and output ends of the first signal lamp, the second signal lamp and the third signal lamp are all electrically connected to the switching power supply.
Specifically, when the voltage output by any one of the three groups of single-phase voltage detectors is smaller than a preset value, the corresponding single-phase voltage detector closes the second alarm circuit and starts a corresponding signal lamp.
Further, the first signal lamp is a yellow display lamp, the second signal lamp is a green display lamp, and the third signal lamp is a red display lamp.
Preferably, the first connection terminal is an eight-core double-plug connection terminal.
Preferably, the second connecting terminal is a three-core double-plug connecting terminal.
Specifically, the first connection terminal and the second connection terminal may be combined into an eleven-core plug, and the eight-core cable of the first connection terminal and the three-core cable of the second connection terminal may be combined into an eleven-core cable; by adopting the plug-in type cable, when an electrician climbs a pole for operation, the other person operates the fault detector on the ground.
Preferably, the ground fault detector further includes a housing, and the zero sequence current transformer, the current relay, the switching power supply, the three groups of single-phase voltage detectors, and the switching power supply are all disposed inside the housing; the multiplying power ammeter, the first signal lamp, the second signal lamp, the third signal and the alarm bell are all arranged on the surface of the shell. Specifically, the magnitude of the ground fault current is displayed through the ammeter, and meanwhile, the ground fault phase is displayed through the first signal lamp, the second signal lamp and the third signal lamp.
Preferably, the ground fault detector further comprises a wire collecting box and a handle, wherein the wire collecting box is arranged at one end, close to the opening CT, of the shell, and the handle is arranged at one end, far away from the wire collecting box, of the shell.
Specifically, the handle is used for carrying the ground fault detector.
Preferably, the ground fault detector further comprises a wireless communication module for communicating with an upper computer.
Specifically, the wireless communication module is assembled on a low-voltage line and a branch line, so that the fault detector is in butt joint with a power distribution operation detection functional unit of a power supply service command system on the current state network. The microcomputer real-time monitoring is realized, the earth fault can be rapidly and accurately eliminated, and the power supply continuity, safety and economy are guaranteed.
The above is only the preferred embodiment of the present invention, not limiting the scope of the present invention, all of which are under the concept of the present invention, the equivalent structure transformation made by the contents of the specification and the drawings is utilized, or the direct/indirect application in other related technical fields is included in the patent protection scope of the present invention.
Claims (9)
1. A low-voltage distribution line ground fault detector is characterized by comprising a zero sequence current transformer, a first opening CT used for collecting current signals of an A matched wire, a second opening CT used for collecting current signals of a B matched wire, a third opening CT used for collecting current signals of a C matched wire, a fourth opening CT used for collecting current signals of a zero line, a first connecting terminal used for respectively inputting the current signals collected by the four opening CTs to the zero sequence current transformer, a multiplying power ammeter used for receiving output currents of the zero sequence current transformer and displaying current values, and a first alarm circuit used for receiving the output currents of the zero sequence current transformer and sending an alarm signal when the output currents of the zero sequence current transformer are larger than a preset value;
the signal output end of the opening CT is connected with four signal input ends in the first wiring terminal in a one-to-one correspondence mode, the signal output end of the first wiring terminal is connected with the signal input end of the zero sequence current transformer, the signal output end of the zero sequence current transformer is electrically connected with the signal input end of the multiplying power ampere meter, and the signal output end of the zero sequence current transformer is electrically connected with the alarm circuit.
2. The apparatus of claim 1, further comprising three sets of single-phase voltage detectors, a grounding down conductor for grounding the three sets of single-phase voltage detectors, three wire clamps for respectively collecting voltage signals between the phases A, B and C relative to ground, second terminals for respectively inputting the voltage signals collected by the three wire clamps to the three sets of single-phase voltage detectors, the grounding down conductor being used for grounding the three sets of single-phase voltage detectors, and a second alarm circuit for receiving the output voltages of the single-phase voltage detectors and activating an alarm when the output voltages of the single-phase voltage detectors are smaller than a preset value;
the signal output end of the wire clamp is respectively and correspondingly electrically connected with the signal input end of the second wiring terminal, the signal output end of each second wiring terminal is respectively and electrically connected with the signal input ends of the three groups of single-phase voltage detectors, the signal output ends of the single-phase voltage detectors are electrically connected with the grounding down lead, and the signal output ends of the three groups of single-phase voltage detectors are all connected in series with the second alarm circuit to be used for disconnecting or connecting the second alarm circuit.
3. The low-voltage distribution line ground fault detector of claim 2, wherein the first alarm circuit comprises a switching power supply and an alarm bell formed with an alarm loop, and a current relay disposed in the alarm loop, wherein an input end of the current relay is electrically connected with a signal output end of the zero-sequence current transformer, and an output end of the current relay is electrically connected with the alarm loop for opening or closing the alarm loop.
4. The low-voltage distribution line ground fault detector of claim 3, wherein the second alarm circuit comprises a first signal lamp, a second signal lamp, a third signal lamp and the switching power supply, an input end of the first signal lamp is electrically connected with an output end of the single-phase voltage detector corresponding to A, an input end of the second signal lamp is electrically connected with an output end of the single-phase voltage detector corresponding to B, an input end of the third signal lamp is electrically connected with an output end of the single-phase voltage detector corresponding to C, and output ends of the first signal lamp, the second signal lamp and the third signal are electrically connected with the switching power supply.
5. The low-voltage distribution line ground fault detector of claim 1, wherein the first terminal is an eight-core dual-pin terminal.
6. The low-voltage distribution line ground fault detector of claim 2, wherein the second terminal is a three-core dual-pin terminal.
7. The low-voltage distribution line ground fault detector of claim 4, wherein the ground fault detector further comprises a housing, the zero sequence current transformer, the current relay, the switching power supply, the three sets of single-phase voltage detectors, and the switching power supply being disposed within the housing; the multiplying power ammeter, the first signal lamp, the second signal lamp, the third signal and the alarm bell are all arranged on the surface of the shell.
8. The low-voltage distribution line ground fault detector of claim 7, further comprising a take-up box disposed at an end of the casing near the opening CT, and a handle disposed at an end of the casing away from the take-up box.
9. The low-voltage distribution line ground fault detector of claim 7, wherein the ground fault detector further comprises a wireless communication module for communicating with an upper computer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020813191.4U CN212410752U (en) | 2020-05-15 | 2020-05-15 | Low-voltage distribution line ground fault detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020813191.4U CN212410752U (en) | 2020-05-15 | 2020-05-15 | Low-voltage distribution line ground fault detector |
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| Publication Number | Publication Date |
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| CN212410752U true CN212410752U (en) | 2021-01-26 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202020813191.4U Active CN212410752U (en) | 2020-05-15 | 2020-05-15 | Low-voltage distribution line ground fault detector |
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| CN (1) | CN212410752U (en) |
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