CN210608530U - Arc suppression cabinet and small current grounding system - Google Patents

Arc suppression cabinet and small current grounding system Download PDF

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Publication number
CN210608530U
CN210608530U CN201921505006.9U CN201921505006U CN210608530U CN 210608530 U CN210608530 U CN 210608530U CN 201921505006 U CN201921505006 U CN 201921505006U CN 210608530 U CN210608530 U CN 210608530U
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circuit breaker
current
current transformer
vacuum circuit
cabinet
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CN201921505006.9U
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于海波
钮晓东
张峰
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Huadian Ruitong Power Engineering Corp
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Huadian Ruitong Power Engineering Corp
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Abstract

The application discloses an arc extinction cabinet and a small current grounding system, wherein the arc extinction cabinet is provided with a switching device, a small current grounding line selection device and a small current grounding line selection device, and the small current grounding line selection device is used for carrying out insulation monitoring sampling on three-phase voltage collected by a first voltage transformer group through a first input end and sampling zero-sequence current of a bus incoming cabinet through a second input end; and when any one phase voltage in the three-phase voltage exceeds a first preset value and/or zero-sequence current exceeds a second preset value, determining a fault phase and a fault type according to the voltage exceeding the first preset value and/or the zero-sequence current exceeding the second preset value, and controlling a switching device to switch a resistive load on a branch corresponding to the fault, so that when a single-phase ground fault occurs, the resistive load is switched on the branch corresponding to the fault, the ground current is changed into resistive-capacitive ground current, the amplitude of the overvoltage of the power grid is suppressed, arc discharge generated at a single-phase ground fault point is suppressed, and the purpose of safe and stable operation of the power system is ensured.

Description

Arc suppression cabinet and small current grounding system
Technical Field
The application relates to the technical field of power equipment, in particular to an arc extinguishing cabinet and a small current grounding system.
Background
At present, in medium-voltage power distribution networks such as 10kV in China, in order to improve the power supply reliability of a power system, most power distribution networks are low-current grounding systems, and the low-current grounding systems are three-phase systems with neutral points not grounded or grounded through arc suppression coils and high impedance, and are also called neutral point indirect grounding systems. When a ground fault occurs in a phase, the ground fault current tends to be much smaller than the load current because a short circuit cannot be formed, so this system is called a "low current grounding system".
In a low-current grounding system, when a single-phase reliable grounding fault occurs on a high-voltage side, only the voltage of the fault phase on the high-voltage side is 0V, and a relatively low induction voltage can be generated on a phase line corresponding to a low-voltage side, so that single-phase electric equipment connected with the phase line cannot work normally. At the moment, the three-phase equipment electrically connected with the high-voltage side or the low-voltage side and the single-phase equipment connected with the other two phases corresponding to the low-voltage side can still run for 2 hours, and meanwhile, the insulation monitoring device gives an alarm to ensure that operating personnel can have sufficient time to process faults, so that the uninterrupted power supply is ensured as far as possible. If the single-phase earth fault does not disappear after 2 hours, the system considers that the earth fault is a permanent fault, and in order to avoid the problem that the single-phase earth fault develops into a two-phase earth short circuit or an interphase short circuit fault, the relay protection can act on the circuit breaker to trip to carry out fault isolation.
However, when the overhead insulated conductor and the overhead bare conductor are grounded on a large ground surface after being disconnected, the overhead insulated conductor and the overhead bare conductor are not reliably grounded, and meanwhile, the end of the conductor has a high voltage difference with the ground surface, so that strong electricity is finally discharged to the ground surface through the end of the conductor to generate synchronous combustion and arc extinction, the brightness is strong, the temperature is high, and the phenomenon is also called arc grounding. And nearly 3 times of capacitance current to ground is generated in the grounding conductor during normal operation, and then the generated ampere force (the ampere force F is BILsin theta) enables the conductor to swing left and right and is accompanied with intermittent arc discharge, thereby generating great harm to surrounding people and equipment, and if the duration is long, generating power system resonance, causing safety accidents such as electric equipment burnout, expanded range power failure and the like.
SUMMERY OF THE UTILITY MODEL
In order to solve the technical problem, the application provides an arc extinction cabinet and a small current grounding system to realize the purpose of restraining single-phase grounding fault points to generate arc discharge and ensuring the safe and stable operation of a power system.
In order to achieve the technical purpose, the embodiment of the application provides the following technical scheme:
an arc suppression cabinet is applied to a small current grounding system, and the small current grounding system comprises a main incoming cabinet and a plurality of feeder cabinets which are connected with a bus in parallel; the arc extinction cabinet includes: the switching device and the low-current grounding line selection device; wherein the content of the first and second substances,
a first input end of the low-current grounding line selection device is connected with a sampling output end of the switching device, a second input end of the low-current grounding line selection device is connected with the main incoming cabinet, and a first output end of the low-current grounding line selection device is connected with a switching input end of the switching device;
the first voltage transformer of the switching device is used for acquiring the three-phase voltage of the bus;
the small-current grounding line selection device is used for performing insulation monitoring sampling on the three-phase voltage acquired by the first voltage transformer group through the first input end and sampling the zero-sequence current of the bus incoming line cabinet through the second input end; and when any one phase voltage in the three-phase voltages exceeds a first preset value and/or the zero-sequence current exceeds a second preset value, determining a fault phase and a fault type according to the voltage exceeding the first preset value and/or the zero-sequence current exceeding the second preset value, and controlling the switching device to switch the resistive load to the branch corresponding to the fault.
Optionally, the arc suppression cabinet further includes: the system comprises a first vacuum circuit breaker, a first current transformer group and a feeder line microcomputer protection device; wherein the content of the first and second substances,
the first vacuum circuit breaker and the first current transformer set are connected in series on one side of the switching device, which faces the bus;
a first sampling end of the feeder microcomputer protection device is connected with the first current transformer set, a second sampling end of the feeder microcomputer protection device is connected with a first voltage transformer of the switching device, and a control output end of the feeder microcomputer protection device is connected with the first vacuum circuit breaker;
the feeder microcomputer protection device is used for sampling the three-phase current collected by the first current transformer group through the first sampling end, sampling the three-phase voltage collected by the first voltage transformer through the second sampling end, determining whether an interphase short-circuit fault occurs according to the three-phase current collected by the first current transformer group and the three-phase voltage collected by the first voltage transformer, and controlling the first vacuum circuit breaker to trip when the interphase short-circuit fault occurs.
Optionally, the low-current ground line selection device controls the switching device to switch the resistive load for the branch corresponding to the fault, specifically, sends a closing instruction to the switching device, so that the switching device switches the resistive load for the branch corresponding to the fault;
and the low-current grounding line selection device is also used for sending a disconnection instruction to the switching device when the fault of the branch corresponding to the fault is eliminated, so that the switching device stops switching the resistive load.
Optionally, the switching device includes: the device comprises a first live display, a switching unit, a voltage transformer group, an overvoltage protector, a primary harmonic elimination device and a fuse protector; wherein the content of the first and second substances,
one end of the first live display is connected with one end of the first current transformer group far away from the vacuum circuit breaker, and the other end of the first live display is grounded;
one end of the switching unit is connected with one end of the first current transformer group far away from the vacuum circuit breaker, and the other end of the switching unit is grounded; the switching unit comprises three switching branches, and each switching branch consists of a single-phase alternating current vacuum contactor, a phase current transformer and a resistor which are sequentially connected in series;
one end of the fuse is connected with one end of the first current transformer group far away from the vacuum circuit breaker, and the other end of the fuse is connected with the voltage transformer group; the voltage transformer group is far away from the fuse group and connected with the primary harmonic eliminator; one end of the primary resonance eliminator, which is far away from the voltage transformer group, is grounded;
one end of the overvoltage protector is connected with one end, far away from the vacuum circuit breaker, of the first current transformer group, and the other end of the overvoltage protector is grounded;
and the single-phase alternating current vacuum contactor is closed when receiving a closing instruction of the low-current grounding line selection device so as to throw capacitive load into the switching branch where the single-phase alternating current vacuum contactor is positioned, and is opened when receiving an opening instruction of the low-current grounding line selection device.
A low current grounding system comprising: the bus, a main incoming cabinet, an arc suppression cabinet and a plurality of feeder cabinets are connected with the bus in parallel;
the arc extinguishing cabinet is any one of the arc extinguishing cabinets.
Optionally, the main incoming cabinet includes: the first vacuum circuit breaker, the first current transformer, the first live display, the first arrester and the first zero sequence current transformer are connected in series; wherein the content of the first and second substances,
one end of the second vacuum circuit breaker is connected with the bus, and the other end of the second vacuum circuit breaker is connected with the second current transformer;
one end of the second electrified display is connected with one end of the second current transformer, which is far away from the second vacuum circuit breaker, and the other end of the second electrified display is grounded;
one end of the first lightning arrester is connected with one end of the second current transformer, which is far away from the second vacuum circuit breaker, and the other end of the first lightning arrester is grounded;
one end of the first zero sequence current transformer is connected with one end, far away from the second vacuum circuit breaker, of the second current transformer, and the other end of the first zero sequence current transformer is connected with a second input end of a small current grounding line selection device of the arc suppression cabinet.
Optionally, the feeder cabinet includes: the third vacuum circuit breaker, the third current transformer, the third live display, the grounding switch, the second lightning arrester and the second zero sequence current transformer; wherein the content of the first and second substances,
one end of the third vacuum circuit breaker is connected with the bus, and the other end of the third vacuum circuit breaker is connected with the third current transformer;
one end of the third live display is connected with one end of the third current transformer, which is far away from the third vacuum circuit breaker, and the other end of the third live display is grounded;
one end of the second lightning arrester is connected with one end of the third current transformer, which is far away from the third vacuum circuit breaker, and the other end of the second lightning arrester is grounded;
and one end of the second zero sequence current transformer is connected with one end of the third current transformer, which is far away from the third vacuum circuit breaker.
According to the technical scheme, the arc extinction cabinet and the small current grounding system are provided, wherein the arc extinction cabinet is provided with a switching device and a small current grounding line selection device, the small current grounding line selection device is used for conducting insulation monitoring sampling on the three-phase voltage collected by the first voltage transformer group through the first input end, and conducting sampling on the zero sequence current of the main incoming cabinet through the second input end; and when any one phase voltage in the three-phase voltages exceeds a first preset value and/or the zero-sequence current exceeds a second preset value, determining a fault phase and a fault type according to the voltage exceeding the first preset value and/or the zero-sequence current exceeding the second preset value, and controlling the switching device to switch the resistive load on the branch corresponding to the fault, so that when a single-phase ground fault occurs, the resistive load is switched on the branch corresponding to the fault, the ground current is changed into resistive-capacitive ground current, the amplitude of the overvoltage of the power grid is suppressed, arc discharge generated by a single-phase ground fault point is suppressed, and the purpose of safe and stable operation of the power system is ensured.
Drawings
In order to more clearly illustrate the embodiments of the present application 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 introduced below, it is obvious that the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic structural diagram of an arc suppression cabinet and a low-current grounding system according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of an arc suppression cabinet and a low-current grounding system according to another embodiment of the present application;
fig. 3 is a schematic structural diagram of a main inlet cabinet according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a feeder cabinet according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The embodiment of the application provides an arc suppression cabinet, which is applied to a low-current grounding system, wherein the low-current grounding system comprises a main incoming cabinet 20 and a plurality of feeder cabinets 30, wherein the main incoming cabinet 20 and the plurality of feeder cabinets 30 are connected with a bus 40 in parallel; the arc extinguishing cabinet 10 includes: a switching device 13 and a low-current grounding line selection device 14; as shown in fig. 1, the arc suppression cabinet 10 includes: a switching device 13 and a low-current grounding line selection device 14; wherein the content of the first and second substances,
a first input end of the low-current grounding line selection device 14 is connected with a sampling output end of the switching device 13, a second input end of the low-current grounding line selection device 14 is connected with the main incoming line cabinet 20, and a first output end of the low-current grounding line selection device 14 is connected with a switching input end of the switching device 13;
a first voltage transformer of the switching device 13 is used for acquiring three-phase voltage of the bus 40;
the low-current grounding line selection device 14 is configured to perform insulation monitoring sampling on the three-phase voltage collected by the first voltage transformer group through the first input end, and sample the zero-sequence current of the main incoming line cabinet 20 through the second input end; and the switching device is used for determining a fault phase and a fault type according to the voltage exceeding the first preset value and/or the zero-sequence current exceeding the second preset value when any one phase voltage in the three-phase voltage exceeds a first preset value and/or the zero-sequence current exceeds a second preset value, and controlling the switching device 13 to switch a resistive load to a branch circuit corresponding to the fault.
In this embodiment, the arc suppression cabinet 10 has a switching device 13 and a low-current grounding line selection device 14, and the low-current grounding line selection device 14 is configured to perform insulation monitoring sampling on the three-phase voltage collected by the first voltage transformer group through the first input end, and sample the zero-sequence current of the bus incoming cabinet 20 through the second input end; and when any one phase voltage in the three-phase voltages exceeds a first preset value and/or the zero-sequence current exceeds a second preset value, determining a fault phase and a fault type according to the voltage exceeding the first preset value and/or the zero-sequence current exceeding the second preset value, and controlling the switching device 13 to switch the resistive load on the branch corresponding to the fault, so that when a single-phase ground fault occurs, the resistive load is switched on the branch corresponding to the fault, the ground current is changed into resistive-capacitive ground current, the amplitude of the overvoltage of the power grid is suppressed, the arc discharge generated by a single-phase ground fault point is suppressed, and the purpose of safe and stable operation of the power system is ensured.
In an optional embodiment of the present application, the low-current ground line selection device is further configured to send an alarm message after determining the fault phase and the fault type.
On the basis of the above embodiment, in an embodiment of the present application, still referring to fig. 1, the arc suppression cabinet 10 further includes: the system comprises a first vacuum circuit breaker 11, a first current transformer group 12 and a feeder line microcomputer protection device 15; wherein the content of the first and second substances,
the first vacuum circuit breaker 11 and the first current transformer group 12 are connected in series on one side of the switching device 13 facing the bus 40;
a first sampling end of the feeder microcomputer protection device 15 is connected with the first current transformer group 12, a second sampling end of the feeder microcomputer protection device 15 is connected with a first voltage transformer of the switching device 13, and a control output end of the feeder microcomputer protection device 15 is connected with the first vacuum circuit breaker 11;
feeder microcomputer protection device 15 for through first sampling end sampling the three-phase current that first current transformer group 12 gathered, through the second sampling end sampling the three-phase voltage that first voltage transformer gathered with be used for according to the three-phase current that first current transformer group 12 gathered with the three-phase voltage that first voltage transformer gathered, confirm whether take place alternate short-circuit fault, and when taking place alternate short-circuit fault, control the tripping operation of first vacuum circuit breaker 11.
Optionally, the model of the low-current grounding line selection device 14 may be HD-NSL 200; the first vacuum circuit breaker 11 can be a 12kV vacuum circuit breaker handcart 1250A 31.5Ka/4S spring mechanism; the first set of current transformers 12 comprises three current transformers for measuring three phase currents, respectively, which may be of the type lzbj 9-10400/510P 2030 VA.
In this embodiment, the feeder microcomputer protection device 15, in cooperation with the first vacuum circuit breaker 11 and the first current transformer group 12, can monitor whether short-circuit faults occur between phases and the like in the arc-extinguishing cabinet 10, and when the faults occur, the feeder microcomputer protection device operates on the first vacuum circuit breaker 11 to trip.
Optionally, the feeder microcomputer protection device 15 may be of a model of CSC 281.
Optionally, the low-current ground line selection device 14 controls the switching device 13 to switch the resistive load for the branch corresponding to the fault, specifically, sends a closing instruction to the switching device 13, so that the switching device 13 switches the resistive load for the branch corresponding to the fault;
the low-current grounding line selection device 14 is further configured to send a disconnection instruction to the switching device 13 when the branch fault corresponding to the fault is eliminated, so that the switching device 13 stops switching the resistive load.
The close command and the open command may be a high level command or a low level command, or may be PWM wave commands with different duty ratios, or the like. The present application does not limit this, which is determined by the actual situation.
Optionally, referring to fig. 2, the switching device 13 includes: a first live display 131, a switching unit, a voltage transformer group 137, an overvoltage protector 136, a primary resonance eliminator 138 and a fuse 135; wherein the content of the first and second substances,
one end of the first live display 131 is connected with one end of the first current transformer group 12 far away from the vacuum circuit breaker, and the other end is grounded;
one end of the switching unit is connected with one end of the first current transformer group 12 far away from the vacuum circuit breaker, and the other end of the switching unit is grounded; the switching unit comprises three switching branches, and each switching branch consists of a single-phase alternating current vacuum contactor 132, a phase current transformer 133 and a resistor 134 which are sequentially connected in series;
one end of the fuse 135 is connected to one end of the first current transformer group 12 far away from the vacuum circuit breaker, and the other end is connected to the voltage transformer group 137; the set of voltage transformers 137 is connected to the primary detuner 138 away from the set of fuses 135; one end of the primary resonance eliminator 138 away from the voltage transformer group 137 is grounded;
one end of the overvoltage protector 136 is connected with one end of the first current transformer group 12 far away from the vacuum circuit breaker, and the other end is grounded;
the single-phase ac vacuum contactor 132 is closed when receiving a closing command of the low-current grounding line selection device 14, so as to put a capacitive load into the switching branch where the single-phase ac vacuum contactor is located, and is opened when receiving an opening command of the low-current grounding line selection device 14.
Wherein, optionally, the model of the first charged display 131 may be DXN-12Q;
the set of voltage transformers 137 includes three voltage transformers for respectively detecting three-phase voltages, and the type of the voltage transformers may be JDZ10-10a 10/√ 3/0.1/√ 3/0.1/3 kV;
the type of the overvoltage protector 136 can be TBP-12.7/35 kV;
the model of the primary resonance eliminator 138 can be LXQ-10 (strong insulation type);
the resistor 134 may be of the type 10kV/100 Ω (stainless steel);
the fuse 135 may be of the type high voltage fuse 135XNP 1-12/0.5A.
Accordingly, embodiments of the present application further provide a low current grounding system, still referring to fig. 1, including: the system comprises a bus 40, a main incoming cabinet 20 connected with the bus 40 in parallel, an arc suppression cabinet 10 and a plurality of feeder cabinets 30;
the arc suppression cabinet 10 is the arc suppression cabinet 10 according to any one of the above embodiments.
Alternatively, referring to fig. 3, the main inlet cabinet 20 includes: a second vacuum circuit breaker 21, a second current transformer 22, a second live display 23, a first lightning arrester 25 and a first zero sequence current transformer 24; wherein the content of the first and second substances,
one end of the second vacuum circuit breaker 21 is connected with the bus 40, and the other end is connected with the second current transformer 22;
one end of the second live display 23 is connected with one end of the second current transformer 22 far away from the second vacuum circuit breaker 21, and the other end is grounded;
one end of the first lightning arrester 25 is connected with one end of the second current transformer 22 far away from the second vacuum circuit breaker 21, and the other end is grounded;
one end of the first zero sequence current transformer 24 is connected with one end of the second current transformer 22 far away from the second vacuum circuit breaker 21, and the other end is connected with a second input end of the small current grounding line selection device 14 of the arc suppression cabinet 10.
The type of the second vacuum circuit breaker 21 can be a 12kV vacuum circuit breaker handcart 1250A 31.5kA/4S spring mechanism;
the second current transformer 22 may be of the type LZBJ 9-10600/50.2S/0.5/10P 2030/30/30 VA.
The second powered display 23 may be of a model DXN-12Q.
The first lightning arrester 25 may be of a type 5WZ-12/45 kV.
The first zero sequence current transformer 24 may be LXK-phi 120100/510 P52.5VA.
The first zero sequence current transformer 24 is configured to collect a zero sequence current of the inlet bus cabinet 20, so that the arc suppression cabinet 10 may sample the zero sequence current of the inlet bus cabinet 20 through the first zero sequence current transformer 24.
Alternatively, referring to fig. 4, the feeder cabinet 30 includes: a third vacuum circuit breaker 31, a third current transformer 32, a third live display 33, a grounding switch 36, a second lightning arrester 35 and a second zero-sequence current transformer 34; wherein the content of the first and second substances,
one end of the third vacuum circuit breaker 31 is connected with the bus 40, and the other end is connected with the third current transformer 32;
one end of the third live display 33 is connected with one end of the third current transformer 32 far away from the third vacuum circuit breaker 31, and the other end is grounded;
one end of the second lightning arrester 35 is connected with one end of the third current transformer 32 far away from the third vacuum circuit breaker 31, and the other end is grounded;
one end of the second zero sequence current transformer 34 is connected to one end of the third current transformer 32 far away from the third vacuum circuit breaker 31.
The type of the third vacuum circuit breaker 31 can be a spring mechanism of a 12kV vacuum circuit breaker handcart 630A 25 kA/4S;
the third current transformer 32 may be of the type LZBJ 9-10400/50.2S/0.5/10P 2030/30/30 VA.
The third powered display 33 may be model DXN-12T.
The ground switch 36 may be of the type JN15-12/25 kA.
The second lightning conductor 35 may be of a type 5WZ-12/45 kV.
The second zero sequence current transformer 34 may be LXK-phi 120100/510 P52.5VA.
In the low-current grounding system, as shown in fig. 1, the arc suppression cabinet 10 includes: a switching device 13 and a low-current grounding line selection device 14; wherein the content of the first and second substances,
a first input end of the low-current grounding line selection device 14 is connected with a sampling output end of the switching device 13, a second input end of the low-current grounding line selection device 14 is connected with the main incoming line cabinet 20, and a first output end of the low-current grounding line selection device 14 is connected with a switching input end of the switching device 13;
a first voltage transformer of the switching device 13 is used for acquiring three-phase voltage of the bus 40;
the low-current grounding line selection device 14 is configured to perform insulation monitoring sampling on the three-phase voltage collected by the first voltage transformer group through the first input end, and sample the zero-sequence current of the main incoming line cabinet 20 through the second input end; and the switching device is used for determining a fault phase and a fault type according to the voltage exceeding the first preset value and/or the zero-sequence current exceeding the second preset value when any one phase voltage in the three-phase voltage exceeds a first preset value and/or the zero-sequence current exceeds a second preset value, and controlling the switching device 13 to switch a resistive load to a branch circuit corresponding to the fault.
In this embodiment, the arc suppression cabinet 10 has a switching device 13 and a low-current grounding line selection device 14, and the low-current grounding line selection device 14 is configured to perform insulation monitoring sampling on the three-phase voltage collected by the first voltage transformer group through the first input end, and sample the zero-sequence current of the bus incoming cabinet 20 through the second input end; and when any one phase voltage in the three-phase voltages exceeds a first preset value and/or the zero-sequence current exceeds a second preset value, determining a fault phase and a fault type according to the voltage exceeding the first preset value and/or the zero-sequence current exceeding the second preset value, and controlling the switching device 13 to switch the resistive load on the branch corresponding to the fault, so that when a single-phase ground fault occurs, the resistive load is switched on the branch corresponding to the fault, the ground current is changed into resistive-capacitive ground current, the amplitude of the overvoltage of the power grid is suppressed, the arc discharge generated by a single-phase ground fault point is suppressed, and the purpose of safe and stable operation of the power system is ensured.
On the basis of the above embodiment, in an embodiment of the present application, still referring to fig. 1, the arc suppression cabinet 10 further includes: the system comprises a first vacuum circuit breaker 11, a first current transformer group 12 and a feeder line microcomputer protection device 15; wherein the content of the first and second substances,
the first vacuum circuit breaker 11 and the first current transformer group 12 are connected in series on one side of the switching device 13 facing the bus 40;
a first sampling end of the feeder microcomputer protection device 15 is connected with the first current transformer group 12, a second sampling end of the feeder microcomputer protection device 15 is connected with a first voltage transformer of the switching device 13, and a control output end of the feeder microcomputer protection device 15 is connected with the first vacuum circuit breaker 11;
feeder microcomputer protection device 15 for through first sampling end sampling the three-phase current that first current transformer group 12 gathered, through the second sampling end sampling the three-phase voltage that first voltage transformer gathered with be used for according to the three-phase current that first current transformer group 12 gathered with the three-phase voltage that first voltage transformer gathered, confirm whether take place alternate short-circuit fault, and when taking place alternate short-circuit fault, control the tripping operation of first vacuum circuit breaker 11.
Optionally, the model of the low-current grounding line selection device 14 may be HD-NSL 200; the first vacuum circuit breaker 11 can be a 12kV vacuum circuit breaker handcart 1250A 31.5Ka/4S spring mechanism; the first set of current transformers 12 comprises three current transformers for measuring three phase currents, respectively, which may be of the type lzbj 9-10400/510P 2030 VA.
In this embodiment, the feeder microcomputer protection device 15, in cooperation with the first vacuum circuit breaker 11 and the first current transformer group 12, can monitor whether short-circuit faults occur between phases and the like in the arc-extinguishing cabinet 10, and when the faults occur, the feeder microcomputer protection device operates on the first vacuum circuit breaker 11 to trip.
Optionally, the feeder microcomputer protection device 15 may be of a model of CSC 281.
Optionally, the low-current ground line selection device 14 controls the switching device 13 to switch the resistive load for the branch corresponding to the fault, specifically, sends a closing instruction to the switching device 13, so that the switching device 13 switches the resistive load for the branch corresponding to the fault;
the low-current grounding line selection device 14 is further configured to send a disconnection instruction to the switching device 13 when the branch fault corresponding to the fault is eliminated, so that the switching device 13 stops switching the resistive load.
The close command and the open command may be a high level command or a low level command, or may be PWM wave commands with different duty ratios, or the like. The present application does not limit this, which is determined by the actual situation.
Optionally, referring to fig. 2, the switching device 13 includes: a first live display 131, a switching unit, a voltage transformer group 137, an overvoltage protector 136, a primary resonance eliminator 138 and a fuse 135; wherein the content of the first and second substances,
one end of the first live display 131 is connected with one end of the first current transformer group 12 far away from the vacuum circuit breaker, and the other end is grounded;
one end of the switching unit is connected with one end of the first current transformer group 12 far away from the vacuum circuit breaker, and the other end of the switching unit is grounded; the switching unit comprises three switching branches, and each switching branch consists of a single-phase alternating current vacuum contactor 132, a phase current transformer 133 and a resistor 134 which are sequentially connected in series;
one end of the fuse 135 is connected to one end of the first current transformer group 12 far away from the vacuum circuit breaker, and the other end is connected to the voltage transformer group 137; the set of voltage transformers 137 is connected to the primary detuner 138 away from the set of fuses 135; one end of the primary resonance eliminator 138 away from the voltage transformer group 137 is grounded;
one end of the overvoltage protector 136 is connected with one end of the first current transformer group 12 far away from the vacuum circuit breaker, and the other end is grounded;
the single-phase ac vacuum contactor 132 is closed when receiving a closing command of the low-current grounding line selection device 14, so as to put a capacitive load into the switching branch where the single-phase ac vacuum contactor is located, and is opened when receiving an opening command of the low-current grounding line selection device 14.
Wherein, optionally, the model of the first charged display 131 may be DXN-12Q;
the set of voltage transformers 137 includes three voltage transformers for respectively detecting three-phase voltages, and the type of the voltage transformers may be JDZ10-10a 10/√ 3/0.1/√ 3/0.1/3 kV;
the type of the overvoltage protector 136 can be TBP-12.7/35 kV;
the model of the primary resonance eliminator 138 can be LXQ-10 (strong insulation type);
the resistor 134 may be of the type 10kV/100 Ω (stainless steel);
the fuse 135 may be of the type high voltage fuse 135XNP 1-12/0.5A.
In summary, the embodiment of the present application provides an arc suppression cabinet and a low current grounding system, wherein the arc suppression cabinet is provided with a switching device and a low current grounding line selection device, and the low current grounding line selection device is used for performing insulation monitoring sampling on a three-phase voltage collected by the first voltage transformer group through the first input end and sampling a zero-sequence current of the main incoming line cabinet through the second input end; and when any one phase voltage in the three-phase voltages exceeds a first preset value and/or the zero-sequence current exceeds a second preset value, determining a fault phase and a fault type according to the voltage exceeding the first preset value and/or the zero-sequence current exceeding the second preset value, and controlling the switching device to switch the resistive load on the branch corresponding to the fault, so that when a single-phase ground fault occurs, the resistive load is switched on the branch corresponding to the fault, the ground current is changed into resistive-capacitive ground current, the amplitude of the overvoltage of the power grid is suppressed, arc discharge generated by a single-phase ground fault point is suppressed, and the purpose of safe and stable operation of the power system is ensured.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (6)

1. An arc suppression cabinet is characterized by being applied to a small current grounding system, wherein the small current grounding system comprises a main incoming cabinet and a plurality of feeder cabinets, and the main incoming cabinet and the feeder cabinets are connected with a bus in parallel; the arc extinction cabinet includes: the switching device and the low-current grounding line selection device; wherein the content of the first and second substances,
the first input end of the low-current grounding line selection device is connected with the sampling output end of the switching device, the second input end of the low-current grounding line selection device is connected with the main incoming line cabinet, and the first output end of the low-current grounding line selection device is connected with the switching input end of the switching device.
2. The arc suppression cabinet of claim 1, further comprising: the system comprises a first vacuum circuit breaker, a first current transformer group and a feeder line microcomputer protection device; wherein the content of the first and second substances,
the first vacuum circuit breaker and the first current transformer set are connected in series on one side of the switching device, which faces the bus;
the first sampling end of the feeder microcomputer protection device is connected with the first current transformer set, the second sampling end of the feeder microcomputer protection device is connected with the first voltage transformer of the switching device, and the control output end of the feeder microcomputer protection device is connected with the first vacuum circuit breaker.
3. The arc suppression cabinet according to claim 2, wherein said switching device comprises: the device comprises a first live display, a switching unit, a voltage transformer group, an overvoltage protector, a primary harmonic elimination device and a fuse protector; wherein the content of the first and second substances,
one end of the first live display is connected with one end of the first current transformer group far away from the vacuum circuit breaker, and the other end of the first live display is grounded;
one end of the switching unit is connected with one end of the first current transformer group far away from the vacuum circuit breaker, and the other end of the switching unit is grounded; the switching unit comprises three switching branches, and each switching branch consists of a single-phase alternating current vacuum contactor, a phase current transformer and a resistor which are sequentially connected in series;
one end of the fuse is connected with one end of the first current transformer group far away from the vacuum circuit breaker, and the other end of the fuse is connected with the voltage transformer group; the voltage transformer group is far away from the fuse group and connected with the primary harmonic eliminator; one end of the primary resonance eliminator, which is far away from the voltage transformer group, is grounded;
one end of the overvoltage protector is connected with one end, far away from the vacuum circuit breaker, of the first current transformer group, and the other end of the overvoltage protector is grounded.
4. A low current grounding system, comprising: the bus, a main incoming cabinet, an arc suppression cabinet and a plurality of feeder cabinets are connected with the bus in parallel;
the arc suppression cabinet is the arc suppression cabinet of any one of claims 1 to 3.
5. The low current grounding system of claim 4, wherein said inlet bus cabinet comprises: the first vacuum circuit breaker, the first current transformer, the first live display, the first arrester and the first zero sequence current transformer are connected in series; wherein the content of the first and second substances,
one end of the second vacuum circuit breaker is connected with the bus, and the other end of the second vacuum circuit breaker is connected with the second current transformer;
one end of the second electrified display is connected with one end of the second current transformer, which is far away from the second vacuum circuit breaker, and the other end of the second electrified display is grounded;
one end of the first lightning arrester is connected with one end of the second current transformer, which is far away from the second vacuum circuit breaker, and the other end of the first lightning arrester is grounded;
one end of the first zero sequence current transformer is connected with one end, far away from the second vacuum circuit breaker, of the second current transformer, and the other end of the first zero sequence current transformer is connected with a second input end of a small current grounding line selection device of the arc suppression cabinet.
6. The low current grounding system of claim 4, wherein said feeder cabinet comprises: the third vacuum circuit breaker, the third current transformer, the third live display, the grounding switch, the second lightning arrester and the second zero sequence current transformer; wherein the content of the first and second substances,
one end of the third vacuum circuit breaker is connected with the bus, and the other end of the third vacuum circuit breaker is connected with the third current transformer;
one end of the third live display is connected with one end of the third current transformer, which is far away from the third vacuum circuit breaker, and the other end of the third live display is grounded;
one end of the second lightning arrester is connected with one end of the third current transformer, which is far away from the third vacuum circuit breaker, and the other end of the second lightning arrester is grounded;
and one end of the second zero sequence current transformer is connected with one end of the third current transformer, which is far away from the third vacuum circuit breaker.
CN201921505006.9U 2019-09-10 2019-09-10 Arc suppression cabinet and small current grounding system Active CN210608530U (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110535116A (en) * 2019-09-10 2019-12-03 北京华电瑞通电力工程技术有限公司 A kind of arc extinction cabinet and small current neutral grounding system
CN113097986A (en) * 2021-03-31 2021-07-09 国网内蒙古东部电力有限公司电力科学研究院 Protection method, device and system for primary harmonic elimination device of distribution network voltage transformer

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110535116A (en) * 2019-09-10 2019-12-03 北京华电瑞通电力工程技术有限公司 A kind of arc extinction cabinet and small current neutral grounding system
CN113097986A (en) * 2021-03-31 2021-07-09 国网内蒙古东部电力有限公司电力科学研究院 Protection method, device and system for primary harmonic elimination device of distribution network voltage transformer

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