CN112003252B - Circuit fault cutting device and direct current system - Google Patents
Circuit fault cutting device and direct current system Download PDFInfo
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- CN112003252B CN112003252B CN202010838132.7A CN202010838132A CN112003252B CN 112003252 B CN112003252 B CN 112003252B CN 202010838132 A CN202010838132 A CN 202010838132A CN 112003252 B CN112003252 B CN 112003252B
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- 238000012423 maintenance Methods 0.000 claims abstract description 26
- 230000009471 action Effects 0.000 claims abstract description 7
- 230000001012 protector Effects 0.000 claims description 16
- 238000001514 detection method Methods 0.000 claims description 13
- 230000005611 electricity Effects 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 3
- 238000010586 diagram Methods 0.000 description 9
- 238000000034 method Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
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- 229910052710 silicon Inorganic materials 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Abstract
The utility model relates to a line fault cutting device and direct current system, line fault cutting device is through being provided with current generating equipment, when arbitrary branch road takes place short circuit trouble, current generating equipment can produce the fault maintenance current, the fault maintenance current passes through direct current busbar flows in the branch road that takes place the short circuit trouble to maintain the short circuit current on the trouble branch road, thereby make on the trouble branch road the circuit breaker action is in order to cut off the short circuit trouble on this branch road. According to the embodiment of the application, the current generation equipment is arranged, so that the technical problem that the working stability of a current direct current system is poor in the prior art is solved, and the technical effect of improving the working stability of the direct current system is achieved.
Description
Technical Field
The application relates to the technical field of power grid fault safety, in particular to a line fault removal device and a direct current system.
Background
Current dc systems generally include a dc bus and branches, each of which is typically provided with a converter. With the increasing development of direct current systems, fault protection of the converters in each branch is improved, the converters can quickly enter a short-circuit protection state when facing short-circuit faults, for safety, each branch is generally provided with a circuit breaker, the short-circuit protection action time of the converters is far less than that of the circuit breaker, when the short-circuit faults occur in the branches, the converters stop working, but the circuit breaker is not opened in time, and the faults cannot be removed in time. When the direct current system is electrified again, as the faults of the fault branch are not removed, the rest branches which are not faulty still enter short-circuit protection and cannot work normally, so that the working stability of the current direct current system is poor.
Disclosure of Invention
Accordingly, it is necessary to provide a line fault removal device and a dc system for solving the problem of poor operation stability of the conventional dc system.
Line fault removal device is applied to direct current system, direct current system includes direct current busbar and a plurality of branch road, parallelly connected between a plurality of branch roads, and respectively with direct current busbar electricity is connected, and every branch road is provided with circuit breaker and the converter of establishing ties, line fault removal device includes:
and the current generating device is electrically connected with the direct current bus and used for generating fault maintaining current, and the intensity of the fault maintaining current is not smaller than that of each branch short circuit current.
In one embodiment, the current generating device comprises:
an alternating current power supply for generating the fault maintenance alternating current;
and the input end of the rectifier is electrically connected with the alternating current power supply, the output end of the rectifier is electrically connected with the direct current bus, and the rectifier is used for converting the fault maintenance alternating current into the fault maintenance current.
In one embodiment, the ac power source is a single phase ac power source.
In one embodiment, the method further comprises:
and the input end of the transformer is electrically connected with the alternating current power supply, and the output end of the transformer is electrically connected with the rectifier.
In one embodiment, the rectifier includes:
the anode of the first diode component is electrically connected with the alternating current power supply, and the cathode of the first diode component is electrically connected with the anode of the direct current bus;
and the cathode of the second diode assembly is electrically connected with the alternating current power supply, and the anode of the second diode assembly is electrically connected with the cathode of the direct current bus.
In one embodiment, the ac power source is a three-phase ac power source;
the first diode component comprises three first diodes, anodes of the three first diodes are respectively and electrically connected with three phases of the alternating current power supply, and cathodes of the three first diodes are electrically connected with anodes of the direct current buses;
the second diode assembly comprises three second diodes, anodes of the three second diodes are respectively and electrically connected with three phases of the alternating current power supply, and cathodes of the three second diodes are electrically connected with cathodes of the direct current bus.
A direct current system comprising:
a DC bus including a positive electrode line and a negative electrode line,
the multiple branches are connected in parallel and are respectively and electrically connected with the direct current bus, and each branch is provided with a circuit breaker and a converter which are connected in series;
the line fault removal device is characterized in that the current generating device is electrically connected with the direct current bus and is used for generating fault maintaining current, and the intensity of the fault maintaining current is not smaller than that of each branch short-circuit current.
In one embodiment, the converter comprises:
a transducer body;
and one end of the protector is electrically connected with the circuit breaker, the other end of the protector is electrically connected with the converter body, and the protector is used for controlling the converter body to stop working when the current flowing through the converter body exceeds a preset threshold value.
In one embodiment, the protector comprises:
the current detection assembly is electrically connected with the converter body and is used for detecting current flowing through the converter body;
and the control assembly is respectively connected with the converter body and the current detection assembly in a signal way and is used for controlling the converter body to stop working when the current flowing through the converter body exceeds a preset threshold value.
In one embodiment, the method further comprises:
the central control equipment is respectively connected with the circuit breakers in a signal way, and is used for determining whether the multiple branches have faults or not according to the action states of the circuit breakers and determining the fault branches when the faults occur.
According to the line fault removal device, the current generation equipment is arranged, when any branch circuit has a short circuit fault, the current generation equipment can generate fault maintenance current, the fault maintenance current flows into the branch circuit with the short circuit fault through the direct current bus so as to maintain the short circuit current on the fault branch circuit, and therefore the circuit breaker on the fault branch circuit acts to cut off the short circuit fault on the branch circuit. According to the embodiment of the application, the current generation equipment is arranged, so that the technical problem that the working stability of a current direct current system is poor in the prior art is solved, and the technical effect of improving the working stability of the direct current system is achieved.
Drawings
In order to more clearly illustrate the technical solutions of embodiments or conventional techniques of the present application, the drawings required for the descriptions of the embodiments or conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.
Fig. 1 is a schematic structural diagram of a line fault removal device and an application environment thereof according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of a current generating device in a line fault removal apparatus according to an embodiment of the present application;
fig. 3 is a schematic structural diagram of a rectifier in the line fault removal device according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a circuit fault removal device and an application environment thereof according to an embodiment of the present application;
fig. 5 is a schematic structural diagram of a circuit fault removal device according to an embodiment of the present application;
fig. 6 is a schematic structural diagram of a dc system according to an embodiment of the present disclosure;
fig. 7 is a schematic diagram of a converter structure in a dc system according to an embodiment of the present disclosure;
fig. 8 is a schematic diagram of a protector in a dc system according to an embodiment of the present disclosure;
fig. 9 is a schematic structural diagram of a dc system according to an embodiment of the present application.
Reference numerals illustrate:
10. a line fault removal device;
100. a current generating device;
110. an alternating current power supply;
120. a rectifier;
121. a first diode assembly;
1211. a first diode;
122. a second diode assembly;
1221. a second diode;
200. a transformer;
30. a direct current system;
300. a direct current bus;
400. a branch;
410. a circuit breaker;
420. a transducer;
421. a transducer body;
422. a protector;
4221. a current detection assembly;
4222. a control assembly;
500. and the central control equipment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the following embodiments are used to further describe a line fault removal device and a dc system of the present application in detail by referring to the accompanying drawings. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.
The numbering of the components itself, e.g. "first", "second", etc., is used herein merely to distinguish between the described objects and does not have any sequential or technical meaning. The terms "coupled" and "connected," as used herein, are intended to encompass both direct and indirect coupling (coupling), unless otherwise indicated. In the description of the present application, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," etc. indicate or refer to an orientation or positional relationship based on that shown in the drawings, merely for convenience of description and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present application.
In this application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.
Referring to fig. 1, an embodiment of the present application provides a line fault removal device 10, which may be applied to a dc system 30 for removing a short-circuit fault in the dc system 30. The dc system 30 generally includes a dc bus 300 and a plurality of branches 400 connected in parallel with each other and electrically connected to the dc bus 300, and each of the branches 400 is provided with a circuit breaker 410 and a converter 420 connected in series with each other. When a short-circuit fault occurs in one of the branches 400, the line fault removal device 10 generates a fault maintenance current to actuate the circuit breaker 410, thereby removing the line fault of the faulty branch 400. The following embodiments are described in detail with respect to the application of the line fault removal apparatus 10 to a dc system 30.
One embodiment of the present application provides a line fault removal apparatus 10 comprising: the current generating apparatus 100.
The current generating device 100 is electrically connected to the dc bus 300, and is configured to generate a fault maintaining current, where the intensity of the fault maintaining current is not less than the intensity of the short-circuit current of each of the branches 400. The current generating device 100 may be a fixed power source, a mobile power source, or other voltage with a stable high current output. The fault maintenance current may be determined according to historical data of daily short-circuit fault currents of the plurality of branches 400, for example, 80A, 106A, etc., or may be determined according to real-time measurement, which is not limited in this embodiment, and may be specifically selected or set according to actual requirements. The fault maintenance current may be fixed or adjustable, for example, according to the load on each branch 400, and the fault maintenance currents with different intensities are determined according to the short circuit current when the branch 400 has a short circuit fault.
The working principle of the line fault removal device 10 provided in the embodiment of the present application is as follows:
the embodiment of the application provides a line fault removal device 10, which comprises a current generation device 100. When the dc bus 300 works normally, the plurality of the branches 400 also works normally, and when a short-circuit fault occurs in one of the branches 400, the current on that branch 400 increases instantaneously, so as to generate a short-circuit current. The operation time of the circuit breaker 410 is much longer than that of the inverter 420, so that once a short-circuit current is generated, the inverter 420 is automatically turned off and a protection mode is started, so that the circuit breaker 410 is not operated, the short-circuit current on the branch 400 is cleared, and the circuit breaker 410 is not operated, which means that the short-circuit fault on the branch 400 is not removed. Once the line is powered up again, the short circuit fault of the branch 400 still exists, and most of the current on the dc bus 300 flows into the faulty branch 400, so that other branches 400 that do not fail cannot work properly. In this embodiment, by providing the current generating device 100, the current generating device 100 may generate a fault maintaining current, where the current generating device 100 is electrically connected with the dc bus 300 to provide the fault maintaining current for the dc bus 300 and the fault branch 400, the fault maintaining current flows into different branches 400 through the dc bus 300, and most of the current flows into the branch 400 where the short circuit fault occurs, so as to maintain the short circuit current of the branch 400 where the short circuit fault occurs, so that the circuit breaker 410 acts, thereby cutting off the short circuit fault on the branch 400. When the line is powered up again, the circuit breaker 410 has been opened, the short circuit fault has been removed, and the other branch 400 can continue to operate normally, thereby maintaining the line in normal and stable operation.
By providing the current generating device 100, when any branch 400 generates a short-circuit fault, the current generating device 100 may generate a fault maintaining current, where the fault maintaining current flows into the branch 400 generating the short-circuit fault through the dc bus 300, so as to maintain the short-circuit current on the fault branch 400, so that the circuit breaker 410 on the fault branch 400 acts to cut off the short-circuit fault on the branch 400. By the current generation device 100, the technical problem that the working stability of the current direct current system 30 is poor in the prior art is solved, and the technical effect of improving the working stability of the direct current system 30 is achieved.
Referring to fig. 2, in one embodiment, the current generating apparatus 100 includes: an ac power source 110 and a rectifier 120.
The ac power supply 110 is configured to generate a fault maintenance ac power. The ac power supply 110 may provide a stable current for the dc bus 300, and is convenient to obtain, for example, the ac power supply may directly obtain power from a power grid, or may directly generate power by using portable power generation devices such as a hand generator, which has high flexibility. The output voltage of the ac power supply 110 may be 110V, 220V, etc., which is not limited in this embodiment, and only needs to satisfy the function of providing stable ac power.
The input end of the rectifier 120 is electrically connected to the ac power source 110, the output end of the rectifier 120 is electrically connected to the dc bus 300, the rectifier 120 is configured to convert ac power into dc power, and in this embodiment, the rectifier 120 is configured to convert the fault maintenance ac power into the fault maintenance current, so as to be conveniently provided to the dc bus 300 for maintaining the short-circuit current in the short-circuit fault branch. The rectifier 120 may be a conventional silicon rectifier, which is mature in technology and relatively low in price, and the rectifier 120 may be any other type of rectifier, and the specific model, type, etc. of the rectifier 120 are not limited in this embodiment, and may be specifically selected according to practical situations, so long as the function of converting the fault maintenance alternating current into the fault maintenance current is satisfied.
Referring to fig. 3, in one embodiment, the rectifier 120 includes: a first diode assembly 121 and a second diode assembly 122.
The anode of the first diode assembly 121 is electrically connected to the ac power source 110, and the cathode of the first diode assembly 121 is electrically connected to the anode of the dc bus 300. The first diode assembly 121 may include a plurality of diodes, which may be connected in parallel or sequentially connected in series, and when the diodes are connected in parallel, anodes of the diodes are electrically connected to the ac power source 110, and cathodes of the diodes are electrically connected to anodes of the dc bus 300. So that each branch 400 is loaded when the dc bus 300 is operating normally, the potential of the dc bus 300 is higher than that of the current generating device 100, and thus the current of the dc bus 300 does not flow back to the current generating device 100. Only when a short-circuit fault occurs at the dc bus 300 end, the load at the end of the branch 400 is reduced, and the potential at the dc bus 300 end is smaller than the potential of the current generating device 100, so that the fault maintaining current generated by the current generating device 100 can flow to the dc bus 300, thereby maintaining the short-circuit current of the fault branch 400, so that the circuit breaker 410 can act to cut off the line fault of the fault branch 400. The diode may be a contact diode, a surface contact diode, a planar diode, or the like, and the embodiment is not particularly limited and may be specifically selected according to practical situations.
The negative electrode of the second diode assembly 122 is electrically connected to the ac power source 110, and the positive electrode of the second diode assembly 122 is electrically connected to the negative electrode of the dc bus 300. The second diode assembly 122 may include a plurality of diodes, which may be connected in parallel or sequentially connected in series, and when the plurality of diodes are connected in parallel, anodes of the plurality of diodes are electrically connected to cathodes of the dc bus 300, and cathodes of the plurality of diodes are electrically connected to the ac power supply 110. The second diode assembly 122 is used for maintaining unidirectional conduction of the circuit, so that current can flow from the negative electrode of the dc bus 300 to the ac power supply 110 in a unidirectional manner, thereby forming a unidirectional loop, and preventing current from flowing back, so as to ensure the operation stability of the current generating device 100 and the whole loop. The diode may be a contact diode, a surface contact diode, a planar diode, or the like, and the embodiment is not particularly limited, and may be specifically selected according to actual situations, and only needs to satisfy the function of realizing unidirectional conduction of the holding loop.
In one embodiment, the ac power source 110 may be a single-phase ac power source 110, that is, one line extracted from a three-phase ac power source in a power grid system is used as a phase line, the other line is used as a zero line, the phase line and the zero line form a loop through a load, and one line is further grounded to serve as a ground, the phase line and the zero line form the loop to provide a stable power supply for the dc bus 300, and the ground line is grounded to play a role of protection. The single-phase alternating current power supply 110 has wide source range, safer use, such as a household 220V alternating current power supply, and the like, and high flexibility.
Referring to fig. 4, in one embodiment, the ac power source 110 is a three-phase ac power source 110, the first diode assembly 121 includes three first diodes 1211, anodes of the three first diodes 1211 are electrically connected to three phases of the ac power source 110, and cathodes of the three first diodes 1211 are electrically connected to anodes of the dc bus 300. The second diode assembly 122 includes three second diodes 1221, anodes of the three second diodes 1221 are respectively electrically connected to three phases of the ac power source 110, and cathodes of the three second diodes 1221 are electrically connected to cathodes of the dc bus 300. The three-phase ac power supply 110 can generate a rotating magnetic field, and save wires in power transmission to reduce cost, and the three-phase ac power supply can utilize an asynchronous motor or the like to supply power, so that the flexibility is high, and meanwhile, the three-phase ac power supply 110 does not exclude power supply to a single-phase load, so that the compatibility is strong, and the application range and the use flexibility of the line fault removal device 10 of the embodiment can be greatly improved through the three-phase ac power supply. The first diode 1211 and the second diode 1221 may be any one or more of a contact diode, a surface contact diode, and a planar diode, which are not specifically limited and may be specifically selected according to practical situations.
Referring to fig. 5, in one embodiment, the line fault removal apparatus 10 further includes: a transformer 200.
The input terminal of the transformer 200 is electrically connected to the ac power source 110, the output terminal of the transformer 200 is electrically connected to the rectifier 120, and the transformer 200 is used for converting the voltage of the ac power source 110 into a preset voltage, that is, a voltage required for generating the fault maintenance current. The preset voltage is set according to actual conditions, and is matched with loads of different direct current systems 30 to make different adjustments, so that the suitability and the application range of the fault removal device can be greatly improved through the transformer 200.
Referring to fig. 6, an embodiment of the present application provides a dc system 30, including: dc bus 300, branch 400, line fault removal apparatus 10.
The dc bus 300 refers to a dc common bus in an electrical system, and belongs to a driving system in the electrical system. The dc bus 300 generally includes two wires: positive and negative lines. The dc system 30 is generally an independent power source, is not affected by the operation mode of the generator and the motor system for the power plant, and can ensure that the backup power source or the storage battery continuously provides dc voltage in the case of external ac power interruption. The dc bus 300 connects the external power source and the loads in the system to form a local topology network for supplying current to each load in the power system. The dc bus 300 may be a plastic cable, a high-middle-low voltage crosslinked cable, etc., where the plastic cable and the high-middle-low voltage crosslinked cable may be buried underground, and have large cross section, and may support high-voltage and ultra-high voltage remote power transmission, so that the application range of the dc system 30 in this embodiment is wider. The type, number, etc. of the dc bus 300 are not limited in this embodiment, and may be specifically selected according to practical situations.
The number of the branches 400 is multiple, the branches 400 are connected in parallel, each branch 400 is electrically connected with the direct current bus 300, and each branch 400 is mutually independent. Each of the branches 400 is a separate line with different loads to perform different functions, but each of the branches 400 is provided with a circuit breaker 410 and a converter 420 connected in series, and the converters 420 are connected in series with different numbers and different types of loads. The circuit breaker 410 is configured to timely disconnect and cut off the short-circuit fault when the short-circuit fault occurs in the branch 400, so as to protect the branch 400 from being damaged or even burned out due to the short-circuit current. The converter 420 is an electronic device for performing DC-DC conversion, and the converter 420 converts the current on the DC bus 300 into the working current required by the load on the branch 400, so as to ensure the working stability of the load on the branch 400.
The line fault removal apparatus 10 includes a current generating device 100 electrically connected to the dc bus 300, for generating a fault maintenance current having a magnitude not less than a magnitude of a short-circuit current of each of the branches 400 to provide an operation current to the faulty branch 400. The beneficial effects of the line fault removal apparatus 10 are already described in the above embodiments, and the description of this embodiment is omitted.
Referring to fig. 7, in one embodiment, the converter 420 includes: a transducer body 421 and a protector 422.
The converter body 421 is used for converting the ac power of the dc bus 300 into the working current required by the load of the branch 400, so as to ensure the working stability of the load of the branch 400. The converter body 421 can realize four-quadrant operation without an intermediate direct current energy storage link, has excellent input current waveform and output voltage waveform, can freely control the power factor, and has high flexibility. The specific type, model, etc. of the converter body 421 in this embodiment are not limited, and may be specifically selected according to practical situations, so long as the function of converting the ac power on the dc bus 300 into the working current required by the load on the branch 400 is satisfied.
One end of the protector 422 is electrically connected to the circuit breaker 410, and the other end is electrically connected to the converter body 421, and the protector 422 is used for controlling the converter body 421 to stop working when the current flowing through the converter body 421 exceeds a preset threshold value. The protector 422 may be a fuse, a circuit breaker, etc., and automatically stops the operation of the inverter body 421 when the current of the branch 400 exceeds a preset threshold. The type and model of the protector 422 are not limited, and may be specifically selected according to practical situations, so long as the function of controlling the converter body 421 to stop working when the current flowing through the converter body 421 exceeds a preset threshold is satisfied.
Referring to fig. 8, in one embodiment, the protector 422 includes: a current detection assembly 4221 and a control assembly 4222.
The current detection component 4221 is electrically connected to the converter body 421, and is configured to detect a current flowing through the converter body 421. The current detection component 4221 may be an ammeter, and is serially connected to the branch 400, for detecting the current in the branch 400, with low cost and easy popularization. The current detection component 4221 may also be a current transformer, which is convenient for measuring large current. The current detection component 4221 may be any other electronic device with a current detection function, and the current detection component 4221 is not particularly limited in this embodiment, and may be specifically selected according to practical situations, so long as the function of detecting the current flowing through the converter body 421 is satisfied.
The control component 4222 is respectively in signal connection with the converter body 421 and the current detection component 4221, and is configured to control the converter body 421 to stop working when the current flowing through the converter body 421 exceeds a preset threshold value, so as to protect the converter body 421 from being damaged due to short-circuit current. The preset threshold may be set according to actual situations, and this embodiment is not limited specifically. The controller may be a microprocessor, a control chip, a PLC chip, etc., and the control unit 4222 is not limited in this embodiment, and may be specifically selected according to practical situations, and only needs to satisfy the function of controlling the converter body 421 to stop working when the current flowing through the converter body 421 exceeds a preset threshold.
Referring to fig. 9, in one embodiment, the dc system 30 further includes: the central control apparatus 500.
The central control device 500 is respectively in signal connection with a plurality of the circuit breakers 410, and the central control device 500 is used for determining whether the plurality of the branches 400 fail according to the action state of the circuit breakers 410 and determining the failed branch 400 when the failure occurs. For example, when the circuit breaker 410 of one of the branches 400 is operated, it may be determined that a short-circuit fault occurs in that branch 400, and when the other branches 400 are not operated, it may be determined that no short-circuit fault occurs in the other branches 400. The central control device 500 can complete fault line selection through the action state of the circuit breaker 410, and the method is simple and easy to operate. The control device may be any electronic device having a data processing function, such as a processor, a server, a mobile phone, a control chip, etc., which is not limited in particular, and only needs to satisfy the function of determining whether a plurality of the branches 400 fail according to the action state of the circuit breaker 410 and determining the failed branch 400 when a failure occurs.
The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples only represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the claims. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.
Claims (10)
1. The utility model provides a line fault excision device, is applied to direct current system, direct current system includes direct current busbar and a plurality of branch road, parallelly connected between a plurality of branch roads, and respectively with direct current busbar electricity is connected, and every branch road is provided with circuit breaker and the converter of series connection, the converter enters short circuit protection state when facing short circuit fault, its characterized in that, line fault excision device includes:
the current generating device is electrically connected with the direct current bus and used for generating fault maintaining current, the strength of the fault maintaining current is not less than that of each branch short-circuit current, and the potential of the current generating device is lower than the potential corresponding to the normal working of the direct current bus end and higher than the potential corresponding to the short-circuit fault of the direct current bus end;
the current generating apparatus includes:
an alternating current power supply for generating the fault maintenance alternating current;
the input end of the rectifier is electrically connected with the alternating current power supply, the output end of the rectifier is electrically connected with the direct current bus, and the rectifier is used for converting the fault maintenance alternating current into the fault maintenance current;
the rectifier includes:
the anode of the first diode component is electrically connected with the alternating current power supply, and the cathode of the first diode component is electrically connected with the anode of the direct current bus;
the cathode of the second diode component is electrically connected with the alternating current power supply, and the anode of the second diode component is electrically connected with the cathode of the direct current bus;
the alternating current power supply is a three-phase alternating current power supply;
the first diode component comprises three first diodes, anodes of the three first diodes are respectively and electrically connected with three phases of the alternating current power supply, and cathodes of the three first diodes are electrically connected with anodes of the direct current buses;
the second diode assembly comprises three second diodes, anodes of the three second diodes are respectively and electrically connected with three phases of the alternating current power supply, and cathodes of the three second diodes are electrically connected with cathodes of the direct current bus.
2. The line fault removal apparatus of claim 1, wherein the ac power source is a single phase ac power source.
3. The line fault removal apparatus of claim 1, further comprising:
and the input end of the transformer is electrically connected with the alternating current power supply, and the output end of the transformer is electrically connected with the rectifier.
4. The line fault removal apparatus of claim 1, wherein the current generating device is a stationary power source, a mobile power source, or a voltage with a stable high current output.
5. The line fault removal apparatus of claim 1, wherein the magnitude of the fault maintenance current is determined based on a short circuit current at which the branch circuit has a short circuit fault.
6. A dc system, comprising:
a DC bus including a positive electrode line and a negative electrode line,
the multiple branches are connected in parallel and are respectively and electrically connected with the direct current bus, and each branch is provided with a circuit breaker and a converter which are connected in series;
the line fault removal apparatus as claimed in any one of claims 1-5, said current generating device being electrically connected to said dc bus for generating a fault maintenance current having a magnitude not less than a magnitude of each of said branch short circuit currents;
the current generating apparatus includes:
an alternating current power supply for generating the fault maintenance alternating current;
the input end of the rectifier is electrically connected with the alternating current power supply, the output end of the rectifier is electrically connected with the direct current bus, and the rectifier is used for converting the fault maintenance alternating current into the fault maintenance current;
the rectifier includes:
the anode of the first diode component is electrically connected with the alternating current power supply, and the cathode of the first diode component is electrically connected with the anode of the direct current bus;
and the cathode of the second diode assembly is electrically connected with the alternating current power supply, and the anode of the second diode assembly is electrically connected with the cathode of the direct current bus.
7. The direct current system according to claim 6, wherein the converter comprises:
a transducer body;
and one end of the protector is electrically connected with the circuit breaker, the other end of the protector is electrically connected with the converter body, and the protector is used for controlling the converter body to stop working when the current flowing through the converter body exceeds a preset threshold value.
8. The direct current system according to claim 7, wherein the protector comprises:
the current detection assembly is electrically connected with the converter body and is used for detecting current flowing through the converter body;
and the control assembly is respectively connected with the converter body and the current detection assembly in a signal way and is used for controlling the converter body to stop working when the current flowing through the converter body exceeds a preset threshold value.
9. The direct current system according to claim 8, further comprising:
the central control equipment is respectively connected with the circuit breakers in a signal way, and is used for determining whether the multiple branches have faults or not according to the action states of the circuit breakers and determining the fault branches when the faults occur.
10. The direct current system of claim 8, wherein the current sensing component is an ammeter.
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