CN114221310A - Protection device and method for direct current system and direct current system - Google Patents
Protection device and method for direct current system and direct current system Download PDFInfo
- Publication number
- CN114221310A CN114221310A CN202111538429.2A CN202111538429A CN114221310A CN 114221310 A CN114221310 A CN 114221310A CN 202111538429 A CN202111538429 A CN 202111538429A CN 114221310 A CN114221310 A CN 114221310A
- Authority
- CN
- China
- Prior art keywords
- direct current
- protection device
- fault
- ground
- input
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- 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
-
- 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
- H02H3/08—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 responsive to excess current
- H02H3/087—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 responsive to excess current for dc applications
Landscapes
- Emergency Protection Circuit Devices (AREA)
Abstract
The invention discloses a protection device and a method of a direct current system and the direct current system, wherein the direct current system comprises a direct current bus and a direct current branch, the protection device is connected between the direct current bus and the direct current branch, and the protection device comprises: the overcurrent protection device is connected with the direct current bus, and a switch tube is arranged in the overcurrent protection device; the acquisition module is used for respectively acquiring a first input signal input to the protection device by the direct-current bus and a first output signal of the protection device; the control module is used for controlling a switching tube in the overcurrent protection equipment to be switched off under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition; and the isolation module is respectively connected with the direct current branch circuit and the control module and is used for isolating at least one of insulation reduction faults, grounding faults and alternating current channeling faults of the direct current system.
Description
Technical Field
The present disclosure relates to the field of power technologies, and in particular, to a protection device and method for a dc system, and a dc system.
Background
The direct current system is an important component of the power system, is a power supply source for relay protection, automation, monitoring, remote control communication and the like, and because the occurrence of a fault in the direct current system can still cause accidents such as incorrect action of relay protection and the like, great harm is caused to the safe and stable operation of the power system, so that the fault protection of the direct current system is particularly important.
In some scenarios, the insulation monitoring device can monitor the loop of the direct current system to realize fault location of the direct current system, but the purpose of protecting the direct current system cannot be realized, and the power supply reliability of the direct current system is low.
Disclosure of Invention
The embodiment of the invention discloses a protection device and a protection method of a direct current system and the direct current system, and aims to solve the problems that the direct current system cannot be protected and the power supply reliability of the direct current system is low.
In a first aspect, an embodiment of the present invention discloses a protection device for a dc system, where the dc system includes a dc bus and a dc branch, the protection device is connected between the dc bus and the dc branch, and the protection device includes: the overcurrent protection device is connected with the direct current bus, and a switch tube is arranged in the overcurrent protection device; the acquisition module is used for respectively acquiring a first input signal input to the protection device by the direct current bus and a first output signal of the protection device; the control module is used for controlling a switching tube in the overcurrent protection equipment to be switched off under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition; and the isolation module is respectively connected with the direct current branch circuit and the control module and is used for isolating at least one of insulation reduction faults, grounding faults and alternating current channeling faults of the direct current system.
In a second aspect, an embodiment of the present invention discloses a method for protecting a dc system, which is applied to the protection device for a dc system mentioned in the first aspect, and the method includes: acquiring a first input signal input to the protection device by a direct current bus and a first output signal of the protection device;
under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition, controlling a switching tube in the protection device to be switched off; determining at least one of an insulation reduction fault, a ground fault, and an ac ingress fault in the dc system; a control isolation module isolates at least one of the insulation reduction fault, the ground fault, and the ac ingress fault.
In a third aspect, an embodiment of the present invention discloses a protection device for a dc system, including: the acquisition module is used for acquiring a first input signal input to the protection device by the direct current bus and a first output signal of the protection device; the first control module is used for controlling a switching tube in the protection device to be switched off under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition; a determination module to determine at least one of an insulation reduction fault, a ground fault, and an ac ingress fault in the dc system; a second control module for controlling an isolation module to isolate at least one of the insulation reduction fault, the ground fault, and the ac ingress fault.
In a fourth aspect, an embodiment of the present invention discloses a dc system, including: the protection device comprises a direct current bus, a direct current branch circuit and the protection device of the direct current system mentioned in the first aspect, wherein the protection device is connected between the direct current bus and the direct current branch circuit.
The embodiment of the invention discloses a protection device of a direct current system, wherein the direct current system comprises a direct current bus and a direct current branch, the protection device is connected between the direct current bus and the direct current branch, and the protection device comprises: the overcurrent protection device is connected with the direct current bus, and a switch tube is arranged in the overcurrent protection device; the acquisition module is used for respectively acquiring a first input signal input to the protection device by the direct-current bus and a first output signal of the protection device; the control module is used for controlling a switching tube in the overcurrent protection equipment to be switched off under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition; and the isolation module is respectively connected with the direct current branch circuit and the control module and is used for isolating at least one of insulation reduction faults, grounding faults and alternating current channeling faults of the direct current system. The direct current system can be subjected to short-circuit protection by controlling the switch tube in the overcurrent protection equipment to be disconnected, at least one of insulation reduction faults, grounding faults and alternating current channeling faults of the direct current system can be isolated through the isolation module, the influence of the faults occurring in the direct current system on the power supply of a normal area in the direct current system is avoided, and the power supply reliability of the direct current system is improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 shows a schematic structural diagram of a dc system provided in an embodiment of the present application;
fig. 2 is a first schematic structural diagram of a protection device of a dc system according to an embodiment of the present disclosure;
fig. 3 is a second schematic structural diagram of a protection device of a dc system according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram illustrating a third protection device of a dc system according to an embodiment of the present disclosure;
fig. 5 is a schematic structural diagram illustrating insulation monitoring of a dc system according to an embodiment of the present disclosure;
fig. 6 is a schematic flowchart illustrating a protection method for a dc system according to an embodiment of the present disclosure;
fig. 7 is a schematic diagram illustrating a module composition of a protection device of a dc system according to an embodiment of the present disclosure;
fig. 8 shows a hardware structure diagram of an electronic device according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. 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.
The following describes a protection device and method for a dc system and a dc system provided in an embodiment of the present application with reference to the accompanying drawings.
Fig. 1 shows a direct current system provided in an embodiment of the present application, the direct current system includes a direct current bus 10, a direct current branch 11, and a protection device 12, the protection device 12 is connected between the direct current bus 10 and the direct current branch 11, in order to individually protect each direct current branch 11, one protection device 12 may be connected to each direct current branch 11, where the direct current bus 10 includes a direct current positive bus 100 and a direct current negative bus 101, as shown in fig. 2, the protection device 12 includes: the overcurrent protection device 120, the control module 121, the isolation module 122 and the acquisition module 123. The overcurrent protection device 120 is respectively connected with the direct current bus 10 and the control module 121, a switching tube is arranged in the overcurrent protection device 120, the acquisition module 123 is respectively connected with the control module 121 and the isolation module 122, and the isolation module 122 is connected to the direct current branch 11.
The acquisition module 123 acquires a first input signal input to the protection device 12 by the dc bus 10 and a first output signal output by the protection device 12, where the first input signal includes a current signal and a voltage signal input by the dc bus 10, and the first output signal includes a voltage signal and a current signal output by the protection device 12. The acquisition module 123 includes, but is not limited to, a current sensor, a voltage sensor, and the like.
The control module 121 is configured to control the switching tube in the over-current protection device 120 to be turned off when the first input signal meets a first preset condition and/or the first output signal meets a second preset condition. Wherein, control module 121 includes the singlechip, and the singlechip includes the ARM treater.
Specifically, the dc system may have a short-circuit fault when the first input signal satisfies a first preset condition and/or the first output signal satisfies a second preset condition, where the first preset condition includes at least one of: the first input current is greater than a first threshold; the first input voltage is less than a second threshold; the second preset condition includes at least one of: the first output current is greater than a third threshold; the first output voltage is less than a fourth threshold. The characteristic that the switching tube in the over-current protection device 120 can be turned off quickly is that, under the condition that the first input signal meets the first preset condition and/or the first output signal meets the second preset condition, the control module 121 sends a Pulse Width Modulation (PWM) signal to the over-current protection device 120, the driving switching tube is turned off quickly, power transmission between the dc bus and the dc branch is stopped, the short-circuit current is cut off, the short-circuit current is prevented from being transmitted to the bus and other dc branches, the fault influence range is further prevented from being expanded, and the short-circuit protection of the dc system is realized.
In one possible implementation, as shown in fig. 3, the over-current protection device 120 includes a DC/DC converter, and an IGBT switching tube 1201 is disposed in the DC/DC converter. The IGBT switch tube has the characteristic of being capable of being rapidly turned off, after the DC/DC converter receives the PWM signal, power transmission between the direct current bus and the direct current branch circuit is stopped, short-circuit current can be rapidly cut off, and the short-circuit current is prevented from being transmitted to the bus and other direct current branch circuits.
The isolation module 122 is connected to the dc branch and the control module, respectively, and is configured to isolate a fault of the dc system, where as shown in fig. 4, the isolation module 122 includes a high-voltage frequency converter, the high-voltage frequency converter includes a positive side 1220 and a secondary side 1221, and the secondary side 1221 includes a diode 1222 and a rectification circuit 1223. Faults in the dc system include, but are not limited to, ground faults, ac ingress faults, and insulation drop faults. Under the condition that a line on one side of a transformer substation has a ground fault, an alternating current entering fault and an insulation descending fault, a high-frequency transformer in the protection device can isolate the ground fault, the alternating current entering fault and the insulation descending fault on the fault side, and normal operation of a direct current bus and other direct current branches is ensured. Meanwhile, the other side is prevented from generating grounding faults, alternating current entering faults and insulation descending faults, and the grounding faults are prevented from being changed into short-circuit faults.
For example, when an ac single-point ingress fault occurs on the dc branch side, the ac single-point cannot form a loop, and normal operation of the dc bus and other dc branches will not be affected, when an ac two-point ingress fault occurs, because the secondary side of the high-voltage frequency converter has the unidirectional conductivity of the rectifier circuit 1223 and the diode 1222, the ac power passes through the diode 1222 and becomes dc power, and the dc power cannot be transmitted through the high-frequency transformer, thereby achieving electrical isolation between the dc bus and the dc branches, ensuring normal operation of the dc bus and other normal dc branches, and improving reliability of power supply of the dc system.
The protection device 12 can perform insulation monitoring on the insulation state of the direct current system, the insulation monitoring adopts an alternating current injection method, as shown in fig. 5, a low-frequency alternating current signal is injected between the ground and the direct current system through an alternating current signal source 124, a capacitor C is connected between the alternating current signal source 124 and a direct current bus, the low-frequency alternating current signal is collected through a collection module 123, the low-frequency alternating current signal is sent to a control module 121, the control module 121 collects the phase angle and the amplitude value of the low-frequency alternating current signal, the insulation resistance of the direct current system is calculated through the phase angle and the amplitude value, and whether insulation reduction faults occur in the direct current system is judged through the insulation resistance. If the insulation resistance exceeds the set value, the insulation reduction fault does not occur in the direct current system, and if the insulation resistance does not exceed the set value, the insulation reduction fault occurs in the direct current system and display and alarm are performed.
In a possible implementation, the protection device 12 further comprises: an alarm device; the alarm device is connected with the control module, and the control module controls the alarm device to send out first alarm information under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition, wherein the first alarm information indicates that the direct-current system has a short-circuit fault; and under the condition that the resistance of the direct current bus relative to the ground exceeds a threshold value, the control module controls the alarm device to send out second alarm information, and the second alarm information indicates that the direct current system has a ground fault. Thereby prompting the staff to solve the fault in time.
Specifically, the alarm device may be a sound, a red and blue light, and the like, and the first alarm information includes, but is not limited to, the type of the fault occurring in the dc system, the place where the fault occurs, and the time when the fault occurs. The second alarm information includes, but is not limited to, the type of the fault, the place where the fault occurred, the time when the fault occurred, and the like.
The ground resistance of the direct current bus relative to the ground comprises the ground resistance of the direct current positive bus relative to the ground and the ground resistance of the direct current negative bus relative to the ground, and second alarm information is sent out when any one of the ground resistance of the direct current positive bus relative to the ground and the ground resistance of the direct current negative bus relative to the ground exceeds a threshold value. The ground resistance value can be calculated according to the ground voltage and the input current, namely the ratio of the ground voltage to the input current is calculated to obtain the ground resistance value.
According to the protection device of the direct current system disclosed by the embodiment of the invention, the short circuit protection can be carried out on the direct current system by controlling the switch tube in the overcurrent protection equipment to be disconnected, at least one of the insulation reduction fault, the grounding fault and the alternating current channeling fault of the direct current system can be isolated through the isolation module, the fault influence range of the direct current system is reduced, the influence of the fault in the direct current system on the power supply of a normal area in the direct current system is avoided, and the power supply reliability of the direct current system is improved.
As shown in fig. 6, an embodiment of the present invention discloses a method for protecting a dc system, which is applied to a protection device of the dc system mentioned in the foregoing embodiment, and includes:
step S601: a first input signal input by the direct current bus to the protection device and a first output signal of the protection device are obtained.
Specifically, the first input signal includes a first input current and a first input voltage, and the first output signal includes a first output current and a first output voltage.
Step S603: and under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition, controlling a switching tube in the protection device to be switched off.
Specifically, the first preset condition includes at least one of: the first input current is greater than a first threshold; the first input voltage is less than a second threshold. The second preset condition includes at least one of: the first output current is greater than a third threshold; the first output voltage is less than a fourth threshold. The switching tube in the protection device can be an IGBT switching tube arranged in the DC/DC converter.
Step S605: at least one of an insulation reduction fault, a ground fault, and an ac ingress fault in the dc system is determined.
Specifically, a voltage to ground of the direct current bus relative to the ground and an input current of the direct current bus are acquired, a resistance to ground value is calculated according to the voltage to ground and the input current, and in the case that the resistance to ground value does not exceed a fifth threshold value, it is determined that a ground fault occurs in the direct current system. And acquiring the phase difference between a voltage signal and a current signal of a low-frequency alternating current signal injected into the direct current system through a signal source, the voltage signal and the amplitude of the current signal, calculating the insulation resistance according to the phase difference, the voltage signal and the amplitude of the current signal, and determining that the insulation reduction fault occurs in the direct current system under the condition that the insulation resistance does not exceed a sixth threshold value. And determining that the alternating current fleeing fault occurs in the direct current system under the condition that the alternating current signal occurs in the direct current system.
Specifically, the insulation-lowering fault is detected by injecting a low-frequency ac signal having a frequency f and an ac signal source having a voltage UsThe current of the AC signal source is IsThen, the voltage and current application of the low-frequency ac signal satisfies the following equation:
the phase difference between the current and the voltage of the low-frequency alternating current signal is represented as theta, and the phase difference between the current and the voltage satisfies the following formula:
then
The measured amplitude of the loop current of the direct current bus and the direct current branch is denoted as I, the measured amplitude of the loop current of the direct current bus and the direct current branch is denoted as U, and the relationship between I and U is shown as follows:
the insulation resistance Z can be calculated by the following formula:
wherein C is a capacitor, R is a ground resistor, f is the frequency of the low-frequency alternating current signal, and Z is an insulation resistor.
Step S607: the control isolation module isolates at least one of an insulation reduction fault, a ground fault, and an ac ingress fault.
Specifically, the isolation module comprises a high-voltage frequency converter, wherein the high-voltage frequency converter comprises a positive side and a secondary side, and the secondary side comprises a diode and a rectifying circuit. Faults in the dc system include, but are not limited to, ground faults, ac ingress faults, and insulation drop faults. Under the condition that a line on one side of a transformer substation has a ground fault, an alternating current entering fault and an insulation descending fault, a high-frequency transformer in the protection device can isolate the ground fault, the alternating current entering fault and the insulation descending fault on the fault side, and normal operation of a direct current bus and other direct current branches is ensured. Meanwhile, the other side is prevented from generating grounding faults, alternating current entering faults and insulation descending faults, and the grounding faults are prevented from being changed into short-circuit faults.
Through the technical scheme disclosed by the embodiment of the application, the direct current system can be subjected to short-circuit protection by controlling the switch tube in the overcurrent protection equipment to be disconnected, at least one of insulation reduction faults, grounding faults and alternating current channeling faults of the direct current system can be isolated through the isolation module, the influence of the faults occurring in the direct current system on the power supply of a normal area in the direct current system is avoided, and the power supply reliability of the direct current system is improved.
In one possible implementation, after the switching tube in the protection device is controlled to be opened, the method further includes: and sending a first alarm prompt, wherein the first alarm prompt indicates that the direct current system has a short-circuit fault.
In one possible implementation, after controlling the isolation module to isolate at least one of the insulation reduction fault, the ground fault, and the ac ingress fault, the method further includes: and sending a second alarm prompt, wherein the second alarm indicates that at least one of insulation reduction faults, grounding faults and alternating current channeling faults of the direct current system occurs.
It should be noted that, the same or similar points of the protection method of the dc system provided in the embodiments of the present application and the protection device of the dc system may be referred to each other, and the embodiments of the present application are not described herein again.
Corresponding to the protection method of the dc system provided in the foregoing embodiment, based on the same technical concept, an embodiment of the present application further provides a protection device of the dc system, and fig. 7 is a schematic diagram of module compositions of the protection device of the dc system provided in the embodiment of the present application, where protection of the dc system is used to execute the protection method of the dc system described in fig. 6, and as shown in fig. 7, the protection device 700 of the dc system includes:
an obtaining module 701, configured to obtain a first input signal input by a dc bus to a protection device, and a first output signal of the protection device; the first control module 702 is configured to control a switching tube in the protection device to be turned off when the first input signal meets a first preset condition and/or the first output signal meets a second preset condition; a determining module 703 for determining at least one of an insulation reduction fault, a ground fault, and an ac ingress fault in the dc system; a second control module 704 for controlling the isolation module to isolate at least one of an insulation reduction fault, a ground fault, and an ac ingress fault.
In one possible implementation, the first input signal includes a first input current and a first input voltage, the first output signal includes a first output current and a first output voltage, and the first preset condition includes at least one of: the first input current is greater than a first threshold; the first input voltage is less than a second threshold; the second preset condition includes at least one of: the first output current is greater than a third threshold; the first output voltage is less than a fourth threshold.
In one possible implementation manner, the method further includes: and the first sending module is used for sending a first alarm prompt, and the first alarm prompt indicates that the direct-current system has a short-circuit fault.
In one possible implementation manner, the method further includes: and the second sending module is used for sending a second alarm prompt, and the second alarm prompt indicates that at least one of insulation reduction faults, grounding faults and alternating current channeling faults of the direct current system occurs.
In a possible implementation manner, the determining module 703 is further configured to obtain a voltage to ground of the dc bus with respect to ground and an input current of the dc bus, calculate a resistance value to ground according to the voltage to ground and the input current, and determine that a ground fault occurs in the dc system if the resistance value to ground does not exceed a fifth threshold; acquiring a phase difference between a voltage signal and a current signal of a low-frequency alternating current signal injected into the direct current system through a signal source, and an amplitude of the voltage signal and an amplitude of the current signal, calculating an insulation resistance according to the phase difference, the voltage signal, the amplitude and the amplitude of the current signal, and determining that an insulation reduction fault occurs in the direct current system under the condition that the insulation resistance does not exceed a sixth threshold; and determining that the alternating current fleeing fault occurs in the direct current system under the condition that the alternating current signal occurs in the direct current system.
The protection device for the dc system provided in the embodiment of the present application can implement each process in the embodiment corresponding to the protection method for the dc system, and is not described here again to avoid repetition.
It should be noted that the apparatus for acquiring the documentary data provided in the embodiment of the present application and the method for acquiring the documentary data provided in the embodiment of the present application are based on the same inventive concept, and therefore specific implementation of the embodiment may refer to implementation of the foregoing method for acquiring the documentary data, and repeated details are not described again.
Based on the same technical concept, the embodiment of the present application further provides an electronic device for executing the method for acquiring the documentary data, and fig. 8 is a schematic structural diagram of an electronic device implementing the embodiments of the present invention, as shown in fig. 8. Electronic devices may vary widely in configuration or performance and may include one or more processors 801 and memory 802, where the memory 802 may store one or more stored applications or data. Wherein the memory 802 may be a transient storage or a persistent storage. The application program stored in memory 802 may include one or more modules (not shown), each of which may include a series of computer-executable instructions for the electronic device. Still further, the processor 801 may be configured to communicate with the memory 802 to execute a series of computer-executable instructions in the memory 802 on the electronic device. The electronic device may also include one or more power supplies 803, one or more wired or wireless network interfaces 804, one or more input-output interfaces 805, one or more keyboards 806.
In this embodiment, the electronic device includes a processor, a communication interface, a memory, and a communication bus; the processor, the communication interface and the memory complete mutual communication through a bus; a memory for storing a computer program; a processor for executing the program stored in the memory, implementing the following method steps:
acquiring a first input signal input to a protection device by a direct current bus and a first output signal of the protection device; under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition, a switching tube in the protection device is controlled to be disconnected; determining at least one of an insulation reduction fault, a ground fault, and an ac ingress fault in a dc system; the control isolation module isolates at least one of an insulation reduction fault, a ground fault, and an ac ingress fault.
Through the technical scheme disclosed by the embodiment of the application,
in one possible implementation, the first input signal includes a first input current and a first input voltage, the first output signal includes a first output current and a first output voltage, and the first preset condition includes at least one of: the first input current is greater than a first threshold; the first input voltage is less than a second threshold; the second preset condition includes at least one of: the first output current is greater than a third threshold; the first output voltage is less than a fourth threshold.
In a possible implementation manner, the processor is further configured to send a first alarm prompt, where the first alarm prompt indicates that the dc system has a short-circuit fault.
In a possible implementation manner, the processor is further configured to issue a second alarm prompt, where the second alarm indicates that at least one of an insulation reduction fault, a ground fault, and an ac ingress fault occurs in the dc system.
In a possible implementation manner, the processor is further configured to acquire a voltage to ground of the direct current bus relative to ground and an input current of the direct current bus, calculate a resistance value to ground according to the voltage to ground and the input current, and determine that a ground fault occurs in the direct current system if the resistance value to ground does not exceed a fifth threshold; acquiring a phase difference between a voltage signal and a current signal of a low-frequency alternating current signal injected into the direct current system through a signal source, and an amplitude of the voltage signal and an amplitude of the current signal, calculating an insulation resistance according to the phase difference, the voltage signal, the amplitude and the amplitude of the current signal, and determining that an insulation reduction fault occurs in the direct current system under the condition that the insulation resistance does not exceed a sixth threshold; and determining that the alternating current fleeing fault occurs in the direct current system under the condition that the alternating current signal occurs in the direct current system.
In the above embodiments of the present invention, the difference between the embodiments is mainly described, and different optimization features between the embodiments can be combined to form a better embodiment as long as they are not contradictory, and further description is omitted here in view of brevity of the text.
The above description is only an example of the present invention, and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (10)
1. A protection device of a direct current system, wherein the direct current system comprises a direct current bus and a direct current branch, the protection device is connected between the direct current bus and the direct current branch, and the protection device comprises:
the overcurrent protection device is connected with the direct current bus, and a switch tube is arranged in the overcurrent protection device;
the acquisition module is used for respectively acquiring a first input signal input to the protection device by the direct current bus and a first output signal of the protection device;
the control module is used for controlling a switching tube in the overcurrent protection equipment to be switched off under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition;
and the isolation module is respectively connected with the direct current branch circuit and the control module and is used for isolating at least one of insulation reduction faults, grounding faults and alternating current channeling faults of the direct current system.
2. The protection device of the direct current system according to claim 1, wherein the over-current protection equipment comprises a DC/DC converter, and an IGBT switching tube is arranged in the DC/DC converter.
3. The protection device of a dc system of claim 1, wherein the isolation module comprises a high voltage inverter.
4. The protection device for a direct current system according to claim 1, further comprising: an alarm device;
the alarm device is connected with the control module, and the control module controls the alarm device to send out first alarm information under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition, wherein the first alarm information indicates that the direct-current system has a short-circuit fault; and under the condition that the ground resistance of the direct current bus relative to the ground exceeds a threshold value, the control module controls the alarm device to send out second alarm information, and the second alarm information indicates that the direct current system has a ground fault.
5. A protection method for a dc system, which is applied to the protection apparatus for a dc system according to any one of claims 1 to 4, comprising:
acquiring a first input signal input to a protection device by a direct current bus and a first output signal of the protection device;
under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition, controlling a switching tube in the protection device to be switched off;
determining at least one of an insulation reduction fault, a ground fault, and an ac ingress fault in the dc system;
a control isolation module isolates at least one of the insulation reduction fault, the ground fault, and the ac ingress fault.
6. The method according to claim 5, wherein the first input signal comprises a first input current and a first input voltage, the first output signal comprises a first output current and a first output voltage, and the first preset condition comprises at least one of:
the first input current is greater than a first threshold;
the first input voltage is less than a second threshold;
the second preset condition comprises at least one of:
the first output current is greater than a third threshold;
the first output voltage is less than a fourth threshold.
7. The method for protecting a dc system according to claim 5, wherein after the controlling of the switching tube in the protection device is turned off, the method further comprises:
sending a first alarm prompt, wherein the first alarm prompt indicates that the direct current system has a short-circuit fault;
after the control isolation module isolates at least one of the insulation reduction fault, the ground fault, and the ac ingress fault, the method further comprises:
sending a second alarm prompt indicating that at least one of the insulation reduction fault, the ground fault, and the AC ingress fault occurs in the DC system.
8. The method of protecting a dc system according to claim 5, wherein the determining at least one of an insulation reduction fault, a ground fault, and an ac ingress fault in the dc system comprises at least one of:
acquiring a voltage to ground of a direct current bus relative to the ground and an input current of the direct current bus, calculating a resistance value to the ground according to the voltage to the ground and the input current, and determining that a ground fault occurs in the direct current system under the condition that the resistance value to the ground does not exceed a fifth threshold;
acquiring a phase difference between a voltage signal and a current signal of a low-frequency alternating current signal injected into a direct current system through a signal source, and an amplitude of the voltage signal and the amplitude of the current signal, calculating an insulation resistance according to the phase difference, the voltage signal and the amplitude of the current signal, and determining that an insulation reduction fault occurs in the direct current system under the condition that the insulation resistance does not exceed a sixth threshold;
and under the condition that the AC signal is detected to appear in the DC system, determining that the AC ingress fault appears in the DC system.
9. A protection device for a dc system, the device comprising:
the acquisition module is used for acquiring a first input signal input to the protection device by the direct current bus and a first output signal of the protection device;
the first control module is used for controlling a switching tube in the protection device to be switched off under the condition that the first input signal meets a first preset condition and/or the first output signal meets a second preset condition;
a determination module to determine at least one of an insulation reduction fault, a ground fault, and an ac ingress fault in the dc system;
a second control module for controlling an isolation module to isolate at least one of the insulation reduction fault, the ground fault, and the ac ingress fault.
10. A direct current system, comprising: direct current bus, direct current branch and the protection device of the direct current system according to any one of claims 1-4, the protection device is connected between the direct current bus and the direct current branch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111538429.2A CN114221310A (en) | 2021-12-15 | 2021-12-15 | Protection device and method for direct current system and direct current system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111538429.2A CN114221310A (en) | 2021-12-15 | 2021-12-15 | Protection device and method for direct current system and direct current system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114221310A true CN114221310A (en) | 2022-03-22 |
Family
ID=80702640
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111538429.2A Pending CN114221310A (en) | 2021-12-15 | 2021-12-15 | Protection device and method for direct current system and direct current system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114221310A (en) |
Citations (5)
| 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 |
| CN110212497A (en) * | 2019-03-28 | 2019-09-06 | 国网辽宁省电力有限公司电力科学研究院 | Based on the substation of fault location DC power supply active protective device and guard method |
| CN110912114A (en) * | 2019-12-06 | 2020-03-24 | 国网江苏电力设计咨询有限公司 | High-safety low-voltage direct current system |
| CN112564061A (en) * | 2020-11-19 | 2021-03-26 | 国网江苏省电力有限公司南通市海门区供电分公司 | Branch protection device for direct current system of transformer substation and protection method thereof |
| CN112600177A (en) * | 2020-11-25 | 2021-04-02 | 云南电网有限责任公司文山供电局 | Active comprehensive protection device of direct current ring network system and working method thereof |
-
2021
- 2021-12-15 CN CN202111538429.2A patent/CN114221310A/en active Pending
Patent Citations (5)
| 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 |
| CN110212497A (en) * | 2019-03-28 | 2019-09-06 | 国网辽宁省电力有限公司电力科学研究院 | Based on the substation of fault location DC power supply active protective device and guard method |
| CN110912114A (en) * | 2019-12-06 | 2020-03-24 | 国网江苏电力设计咨询有限公司 | High-safety low-voltage direct current system |
| CN112564061A (en) * | 2020-11-19 | 2021-03-26 | 国网江苏省电力有限公司南通市海门区供电分公司 | Branch protection device for direct current system of transformer substation and protection method thereof |
| CN112600177A (en) * | 2020-11-25 | 2021-04-02 | 云南电网有限责任公司文山供电局 | Active comprehensive protection device of direct current ring network system and working method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| RU2584096C2 (en) | Direct voltage power switch | |
| WO2019119886A1 (en) | Series compensator, and control method | |
| US9257829B2 (en) | Grounding apparatus | |
| Liu et al. | An improved SSCB combining fault interruption and fault location functions for DC line short-circuit fault protection | |
| CN107765112B (en) | Converter valve overcurrent turn-off test circuit, method and device | |
| CN103812209A (en) | Techniques for improving operation of static transfer switches during voltage disturbances | |
| CN103891082A (en) | Interface arrangement between ac and dc systems for reliable opening of the circuit breaker in time | |
| CN105140889A (en) | Inverter over-current protection circuit | |
| CN113097957B (en) | Voltage source type direct-current ice melting device, flexible interconnection system and control method | |
| CN108469557B (en) | High voltage direct current transmission device Fault Locating Method based on inverter differential protection | |
| CN112636312B (en) | Micro-grid protection method based on injected zero-sequence characteristic signal | |
| CN103715656B (en) | The over-pressure safety device of chopper, chopper and electric locomotive | |
| CN114221310A (en) | Protection device and method for direct current system and direct current system | |
| CN111130072A (en) | Novel active protection device in direct current system | |
| CN108146261B (en) | Fault protection method and device for electric vehicle rapid charging station | |
| Solangi et al. | Selective Coordination of GaN-Based Solid State Circuit Breakers | |
| CN108964433A (en) | A kind of overall process Inrush current restraining generalization device and control method based on PWM closed-loop control | |
| CN210123943U (en) | Alternating current channeling fault isolation module of direct current system of transformer substation | |
| CN107994545B (en) | A kind of the protection circuit and electric system of blower | |
| CN113595040A (en) | Annular direct-current micro-grid single-ended current type distance measurement method based on control and protection cooperation | |
| CN114914887B (en) | Three-phase overcurrent detection protection system and overcurrent protection equipment applied to APF | |
| CN111968334A (en) | Fire detection method and uninterruptible power supply | |
| Bottrell et al. | An impedance-based method for the detection of over-load and network faults in inverter interfaced distributed generation | |
| CN112798869A (en) | Capacitance detection method and system for unit series type converter | |
| CN219960114U (en) | DC ring network protection device and DC power supply system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |