CN112564063A - Active grounding protection device of direct current ring network system and working method thereof - Google Patents
Active grounding protection device of direct current ring network system and working method thereof Download PDFInfo
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- CN112564063A CN112564063A CN202011340912.5A CN202011340912A CN112564063A CN 112564063 A CN112564063 A CN 112564063A CN 202011340912 A CN202011340912 A CN 202011340912A CN 112564063 A CN112564063 A CN 112564063A
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- 238000000034 method Methods 0.000 title claims abstract description 13
- 238000002955 isolation Methods 0.000 claims abstract description 34
- 238000005070 sampling Methods 0.000 claims abstract description 20
- 238000001514 detection method Methods 0.000 claims description 31
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 239000003990 capacitor Substances 0.000 abstract description 11
- 230000007257 malfunction Effects 0.000 description 6
- 238000010586 diagram Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000012806 monitoring device Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000008280 blood Substances 0.000 description 1
- 210000004369 blood Anatomy 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
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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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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/02—Details
- H02H3/04—Details with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned
- H02H3/042—Details with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned combined with means for locating the fault
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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
- Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
- Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
- Y04S10/00—Systems supporting electrical power generation, transmission or distribution
- Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications
- Y04S10/52—Outage or fault management, e.g. fault detection or location
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Abstract
The invention relates to an active grounding protection device of a direct current ring network system and a working method thereof, wherein the device comprises an isolation unit, a control unit and a sampling unit, wherein the isolation unit is connected between a direct current bus and a load of the direct current ring network system; the sampling unit is used for collecting voltages at two ends of a load; the control unit is used for outputting a control signal according to the voltage; and the isolation unit is used for switching to a cut-off state according to the control signal when the direct current ring network system has an earth fault so as to isolate the direct current bus from the load. When the grounding fault occurs, the control unit drives the isolation unit to isolate the direct current bus from the load, so that the influence of the fault on other branches is avoided, the isolation unit is arranged to reduce the distribution of the capacitor, an alarm signal can be sent out in time when the grounding fault occurs, the phenomenon that the capacitor discharges to cause protection misoperation due to one-point grounding of direct current is avoided, the grounding fault can be limited on one side of the direct current load, and the influence range of the fault is prevented from being expanded.
Description
Technical Field
The invention relates to a direct current ring network system, in particular to an active grounding protection device of the direct current ring network system and a working method thereof.
Background
As an important component of the power secondary system, the direct current ring network system is a direct current power supply of relay protection, an automatic device, monitoring, remote control communication, an operation loop, a signal loop, a microcomputer, a five-prevention system, a safety and stability device and the like, and is blood for the operation of the relay protection and safety and stability device.
In the operation process of a power grid, the fault of a direct current ring network system causes the accident of incorrect action of relay protection, the damage to the safe and stable operation of a power system is large, particularly the incorrect action of the relay protection of an ultrahigh voltage system causes the accident to be enlarged, the power grid to be stably damaged, large-area power failure, equipment damage and the like, the serious loss is caused to national economy, and the training is heavy.
The faults of the direct current ring network system include ground faults, and the ground faults can be divided into 3 types of anode grounding, cathode grounding and two-point grounding. The positive electrode may be grounded to cause malfunction of the relay protection and the automatic apparatus. The tripping and closing coil is usually connected with the negative power supply, and if the positive power supply crosses an operation button or a switch contact at the moment, malfunction may be caused when the positive power supply is grounded. The negative ground may disable the relay protection and the automatic device. The tripping coil and the closing coil are short-circuited by the grounding point at the moment to generate the action rejection. Two point grounding may short certain relays to trip or even cause an override trip. More seriously, the short-circuit current of two points of the direct current loop grounding can cause the power supply fuse to be fused, and possibly burn out the relay contact, and the protection, the operation and the like can lose the power supply by the fusing of the direct current fuse. That is to say, once the ground fault of the dc ring network system occurs, the current system cannot limit the fault in time, and cannot expand the influence range of the limiting fault, and once the ground fault of the dc ring network system occurs, especially if the dc ring network system is grounded at one point, the capacitor discharge is easily caused to cause the protection malfunction.
Therefore, it is necessary to design a new device to prevent the capacitor discharge from causing the protection malfunction due to the one-point direct current grounding, and to limit the grounding fault to the load side, thereby avoiding the expansion of the fault influence range.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides an active grounding protection device of a direct current ring network system and a working method thereof.
In order to achieve the purpose, the invention adopts the following technical scheme: the active grounding protection device of the direct current ring network system comprises an isolation unit, a control unit and a sampling unit, wherein the isolation unit is connected between a direct current bus and a load of the direct current ring network system; the sampling unit is used for collecting voltages at two ends of a load; the control unit is used for outputting a control signal according to the voltage; and the isolation unit is used for switching to a cut-off state according to the control signal when the direct current ring network system has an earth fault so as to isolate the direct current bus from the load.
The further technical scheme is as follows: the isolation unit comprises an isolation type DC/DC conversion subunit.
The further technical scheme is as follows: the isolated DC/DC conversion subunit comprises an insulated gate bipolar transistor and a high-frequency transformer, the insulated gate bipolar transistor is connected with the direct-current bus, the high-frequency transformer is connected with the load, and the insulated gate bipolar transistor is connected with the control unit.
The further technical scheme is as follows: the sampling unit comprises a first detection resistor and a second detection resistor, one end of the first detection resistor is connected with the load, the other end of the first detection resistor is connected with the second detection resistor, and the second detection resistor is connected with the other end of the load.
The further technical scheme is as follows: one end of the first detection resistor is grounded.
The further technical scheme is as follows: the alarm device also comprises an alarm unit, and the alarm unit is connected with the control unit.
The further technical scheme is as follows: the alarm unit includes at least one of a buzzer and an indicator light.
The further technical scheme is as follows: and a first switch is connected between one end of the first detection resistor and the load.
The further technical scheme is as follows: and a second switch is connected between the second detection resistor and the other end of the load.
The invention also provides a working method of the active grounding protection device of the direct current ring network system, which comprises the following steps:
the sampling unit collects voltages at two ends of a load; the control unit outputs a control signal according to the voltage; and the isolation unit is switched to a cut-off state according to the control signal when the direct current ring network system has an earth fault, so that the direct current bus is isolated from the load.
Compared with the prior art, the invention has the beneficial effects that: according to the invention, the isolation unit, the control unit and the sampling unit are arranged, the voltage at two ends of the load is collected through the sampling unit, whether the ground fault occurs is judged by the control unit, when the ground fault occurs, the control unit drives the isolation unit to isolate the direct current bus from the load, so that the influence of the route where the fault occurs on other branches is avoided, the isolation unit is arranged to reduce the distribution of the capacitor, an alarm signal can be sent out in time when the ground fault occurs, the protection misoperation caused by capacitor discharge due to one-point grounding of direct current is prevented, the ground fault can be limited at one side of the direct current load, and the influence range of the fault is prevented from being expanded.
The invention is further described below with reference to the accompanying drawings and specific embodiments.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a wiring circuit diagram of an active ground protection device of a dc ring network system according to an embodiment of the present invention;
fig. 2 is a schematic block diagram of an active ground protection device of a dc ring network system according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an unbalanced bridge method of an active ground protection device of a dc ring network system according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and the detailed description.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, 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 invention.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be connected or detachably connected or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above should not be understood to necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.
As shown in fig. 1 to 3, the active ground protection device of the dc ring network system provided in this embodiment can be applied to a dc ring network system, so as to prevent a capacitor from discharging to cause a protection malfunction due to a point ground of a dc, and limit a ground fault on one side of a load 50, thereby avoiding an expansion of an influence range of the fault.
Referring to fig. 1, the active grounding protection device of the dc ring network system is connected between the dc bus 60 and each load 50 in series in the dc ring network system, so that the bus is segmented, the distributed capacitance is greatly reduced, and the capacitor discharge caused by the dc point grounding is prevented from causing protection malfunction to a certain extent. The active ground protection in the figure is an active ground protection device of the dc ring network system.
According to the requirements of Q/GDW 11078-2013 'direct current power supply system technical supervision and guidance rule 5.2.2', a direct current system should have technical measures for preventing capacitor discharge from causing protection maloperation due to 'direct current one point grounding'; a set of microcomputer monitoring devices should be arranged in the direct current system according to each set of direct current buses 60; the microcomputer monitoring device is an active grounding protection device of the direct current ring network system in the embodiment, and has functions of measuring, recording, selecting and alarming when alternating current flees into direct current.
Referring to fig. 2, the active ground protection device of the dc ring network system includes an isolation unit 10, a control unit 20 and a sampling unit 30, wherein the isolation unit 10 is connected between a dc bus 60 and a load 50 of the dc ring network system; the sampling unit 30 is used for collecting voltages at two ends of the load 50; a control unit 20 for outputting a control signal according to the voltage; and the isolation unit 10 is used for switching to a cut-off state according to the control signal when the direct current ring network system has an earth fault, so that the direct current bus 60 is isolated from the load 50.
The sampling unit 30 collects voltages at two ends of the load 50 in real time, the control unit 20 judges whether an earth fault exists between the direct current bus 60 and the load 50 according to the voltages, and when the earth fault occurs, the control unit 20 timely controls the isolation unit 10 to isolate the direct current bus 60 from the load 50, so that electrical isolation between a power supply side and the load 50 side is realized, the earth fault can be limited to the load 50 side, and the whole direct current ring network system can normally operate before the fault is cleared.
In an embodiment, the isolation unit 10 includes an isolation type DC/DC conversion sub-unit. The isolated DC/DC conversion subunit is an isolated DC/DC converter.
In an embodiment, the isolated DC/DC converter subunit includes an insulated gate bipolar transistor and a high frequency transformer, the insulated gate bipolar transistor is connected to the DC bus 60, the high frequency transformer is connected to the load 50, and the insulated gate bipolar transistor is connected to the control unit 20.
In the present embodiment, a high-frequency transformer is integrated as the isolation unit 10 in the isolation type DC/DC converter. For a direct current ring network system composed of storage batteries, positive and negative buses of the direct current ring network system are suspended, namely floating, the positive and negative buses of the storage batteries are used as an input power supply of an isolated DC/DC converter, and are converted into high-frequency pulse square waves through the switching on and off of Insulated Gate Bipolar Transistors (IGBTs) so as to be transmitted from a primary side to a secondary side of a high-frequency transformer to supply power to a load 50, and the converter realizes power transmission and voltage conversion under the control of the IGBTs. When a certain load 50 branch is grounded, the secondary side of the high-frequency transformer in the isolated DC/DC converter has no power tube control, and the physical characteristics of the high-frequency transformer cannot realize the energy transmission from the load 50 side to the power supply side, and the electrical isolation between the power supply side and the load 50 side is realized, so the ground fault can be limited to the load 50 side. Therefore, in case of grounding of the load 50 branch, the alarm unit 40 gives an alarm, and the system can be operated normally before the fault is cleared.
In an embodiment, the sampling unit 30 includes a first detection resistor and a second detection resistor, one end of the first detection resistor is connected to the load 50, the other end of the first detection resistor is connected to the second detection resistor, and the second detection resistor is connected to the other end of the load 50.
In addition, one end of the first detection resistor is grounded.
In one embodiment, a first switch is connected between one end of the first detection resistor and the load 50.
In one embodiment, a second switch is connected between the second detection resistor and the other end of the load 50.
Referring to fig. 3, the active ground protection device of the dc ring network system detects a ground fault by using an unbalanced bridge method, and measures voltages of a first detection resistor and a second detection resistor in different switch states through a sampling circuit, where the first detection resistor is a resistor R1 and a resistor R2 of the second detection resistor; the ground insulation resistance R + and R-of the positive bus and the negative bus are obtained through the operation of the control unit 20 based on the single chip microcomputer, and compared with a setting value, the alarm and fault isolation are carried out.
In an embodiment, referring to fig. 2, the active ground protection device of the dc ring network system further includes an alarm unit 40, and the alarm unit 40 is connected to the control unit 20.
Specifically, the alarm unit 40 includes at least one of a buzzer and an indicator lamp.
The active ground protection device of the direct current ring network system comprises an isolation unit 10, a control unit 20 and a sampling unit 30, the sampling unit 30 is used for collecting voltages at two ends of a load 50, the control unit 20 is used for judging whether a ground fault occurs or not, when the ground fault occurs, the control unit 20 drives the isolation unit 10 to isolate a direct current bus 60 from the load 50, therefore, the phenomenon that other branches are influenced by a route where the fault occurs is avoided, the isolation unit 10 is arranged to reduce the distribution of capacitors, when the ground fault occurs, an alarm signal can be sent out timely, the phenomenon that the capacitors are discharged to cause protection misoperation due to one-point grounding of direct current is avoided, the ground fault can be limited on one side of the direct current load 50, and the influence range of the fault is prevented from being enlarged.
In an embodiment, there is further provided a working method of the active ground protection device of the dc loop network system, including:
the sampling unit 30 collects voltages at two ends of the load 50; the control unit 20 outputs a control signal according to the voltage; the isolation unit 10 is switched to a cut-off state according to a control signal when the dc ring network system has an earth fault, so that the dc bus 60 is isolated from the load 50.
It should be noted that, as will be clearly understood by those skilled in the art, the specific implementation process of the working method of the active ground protection device of the dc ring network system may refer to the corresponding description in the embodiment of the active ground protection device of the dc ring network system, and for convenience and brevity of description, no further description is provided herein.
The technical contents of the present invention are further illustrated by the examples only for the convenience of the reader, but the embodiments of the present invention are not limited thereto, and any technical extension or re-creation based on the present invention is protected by the present invention. The protection scope of the invention is subject to the claims.
Claims (10)
1. The active grounding protection device of the direct current ring network system is characterized by comprising an isolation unit, a control unit and a sampling unit, wherein the isolation unit is connected between a direct current bus and a load of the direct current ring network system; the sampling unit is used for collecting voltages at two ends of a load; the control unit is used for outputting a control signal according to the voltage; and the isolation unit is used for switching to a cut-off state according to the control signal when the direct current ring network system has an earth fault so as to isolate the direct current bus from the load.
2. The active ground protection device of a DC ring network system of claim 1, wherein the isolation unit comprises an isolated DC/DC conversion subunit.
3. The active ground protection device of the direct current loop network system according to claim 2, wherein the isolated DC/DC conversion subunit includes an insulated gate bipolar transistor and a high frequency transformer, the insulated gate bipolar transistor is connected to the direct current bus, the high frequency transformer is connected to the load, and the insulated gate bipolar transistor is connected to the control unit.
4. The active ground protection device of a dc loop network system of claim 1, wherein the sampling unit includes a first detection resistor and a second detection resistor, one end of the first detection resistor is connected to the load, the other end of the first detection resistor is connected to the second detection resistor, and the second detection resistor is connected to the other end of the load.
5. The active ground protection device of a dc ring network system as claimed in claim 4, wherein one end of the first detection resistor is grounded.
6. The active ground protection device of a dc ring network system of claim 1, further comprising an alarm unit, wherein the alarm unit is connected to the control unit.
7. The active ground protection device of a dc ring network system as claimed in claim 6, wherein the alarm unit comprises at least one of a buzzer and an indicator light.
8. The active ground protection device of a dc ring network system of claim 4, wherein a first switch is connected between one end of the first detection resistor and the load.
9. The active ground protection device of a dc ring network system as claimed in claim 4, wherein a second switch is connected between the second detection resistor and the other end of the load.
10. The working method of the active grounding protection device of the direct current ring network system is characterized by comprising the following steps:
the sampling unit collects voltages at two ends of a load; the control unit outputs a control signal according to the voltage; and the isolation unit is switched to a cut-off state according to the control signal when the direct current ring network system has an earth fault, so that the direct current bus is isolated from the load.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011340912.5A CN112564063A (en) | 2020-11-25 | 2020-11-25 | Active grounding protection device of direct current ring network system and working method thereof |
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| CN202011340912.5A CN112564063A (en) | 2020-11-25 | 2020-11-25 | Active grounding protection device of direct current ring network system and working method thereof |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107703404A (en) * | 2017-09-21 | 2018-02-16 | 国网浙江省电力公司电力科学研究院 | The active earth protective device of straight-flow system and its guard method of use |
| CN109873408A (en) * | 2019-03-28 | 2019-06-11 | 国网辽宁省电力有限公司电力科学研究院 | A kind of substation quickly isolates device and partition method with D. C. power source breakdown |
| CN111130072A (en) * | 2019-12-30 | 2020-05-08 | 国网辽宁省电力有限公司电力科学研究院 | Novel active protection device in direct current system |
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2020
- 2020-11-25 CN CN202011340912.5A patent/CN112564063A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107703404A (en) * | 2017-09-21 | 2018-02-16 | 国网浙江省电力公司电力科学研究院 | The active earth protective device of straight-flow system and its guard method of use |
| CN109873408A (en) * | 2019-03-28 | 2019-06-11 | 国网辽宁省电力有限公司电力科学研究院 | A kind of substation quickly isolates device and partition method with D. C. power source breakdown |
| CN111130072A (en) * | 2019-12-30 | 2020-05-08 | 国网辽宁省电力有限公司电力科学研究院 | Novel active protection device in direct current system |
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