CN112260236B - Three-phase self-adaptive reclosing method and device - Google Patents
Three-phase self-adaptive reclosing method and device Download PDFInfo
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- CN112260236B CN112260236B CN202010978894.7A CN202010978894A CN112260236B CN 112260236 B CN112260236 B CN 112260236B CN 202010978894 A CN202010978894 A CN 202010978894A CN 112260236 B CN112260236 B CN 112260236B
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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
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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
- H02H3/06—Details with automatic reconnection
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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
- H02H3/06—Details with automatic reconnection
- H02H3/066—Reconnection being a consequence of eliminating the fault which caused disconnection
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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
- H02H7/265—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 making use of travelling wave theory
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
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- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
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Abstract
The invention discloses a three-phase self-adaptive reclosing method and a device, wherein the method comprises the following steps: the method comprises the following steps that circuit breakers of parallel-connection type closing resistors are respectively arranged at two ends of a power transmission line, each circuit breaker comprises a main contact, an auxiliary contact and a closing resistor, and the resistance of each closing resistor is adjusted to be equal to the line wave impedance of the power transmission line; monitoring the state of the breaker, detecting three-phase tripping, controlling the auxiliary contact to be closed, and collecting voltage traveling waves generated when the auxiliary contact is closed and the switching-on resistor is switched on through a voltage traveling wave measuring device; and extracting a first wavelet transform mode maximum point of the voltage initial traveling wave and a second wavelet transform mode maximum point of the first reflection traveling wave, judging the type of the line fault, locking the main contact and disconnecting the auxiliary contact according to the type of the line fault. The invention can accurately identify the fault types except the three-phase fault, has strong transition resistance capability and can effectively prevent overvoltage impact caused by the fact that the three-phase reclosing is superposed on the permanent fault.
Description
Technical Field
The invention relates to the power system technology, in particular to a three-phase self-adaptive reclosing method and a device.
Background
Automatic reclosing is widely used in power transmission lines because it can quickly recover the line trip caused by transient faults. The traditional automatic reclosing device widely adopts a fixed time interval automatic reclosing strategy, and when the reclosing is carried out on a permanent fault or a transient fault is not extinguished, serious secondary impact is generated on an electric power system and electric power equipment on a line. The adaptive reclosing system can accurately identify the fault property and capture the transient fault extinguishing time, and becomes a research hotspot in recent years.
However, most of the research currently focuses on single-phase adaptive reclosing, and the main method is to distinguish the fault property according to the electrical characteristics of the fault phase terminal voltage generated by the coupling of healthy two phases on the fault open phase. After three phases of a transmission line without a shunt reactor are tripped, residual voltage stored by a line capacitor is in a direct current attenuation characteristic, and useful fault characteristic information can hardly be extracted through the conventional voltage transformer, so that related research is few. And the overvoltage impact caused when the three-phase reclosure is coincided with the permanent fault is larger than that of the single-phase reclosure.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a three-phase self-adaptive reclosing method which can effectively extract fault characteristic information so as to avoid reclosing on a permanent fault.
The invention also provides a three-phase self-adaptive reclosing device based on the three-phase self-adaptive reclosing method.
According to the embodiment of the first aspect of the invention, the three-phase adaptive reclosing method comprises the following steps: the circuit breaker is characterized in that the two ends of a power transmission line are respectively provided with a circuit breaker of a parallel-connection type closing resistor, the circuit breaker comprises a main contact, an auxiliary contact and a closing resistor, one end of the auxiliary contact is connected with one end of the closing resistor to form an auxiliary closing branch, the auxiliary closing branch is connected with the main contact in parallel, and the resistance of the closing resistor is adjusted to be equal to the line wave impedance of the power transmission line; monitoring the state of the circuit breaker, detecting three-phase tripping, controlling the auxiliary contact to be closed, and collecting voltage traveling waves generated when the auxiliary contact is closed and the closing resistor is switched on through a voltage traveling wave measuring device arranged on the power transmission line; based on wavelet analysis, extracting a first wavelet transformation mode maximum point of the voltage initial traveling wave and a second wavelet transformation mode maximum point of the first reflection traveling wave in the voltage traveling wave, judging a line fault type according to the first wavelet transformation mode maximum point and the second wavelet transformation mode maximum point, and locking the main contact and disconnecting the auxiliary contact according to the line fault type.
The three-phase self-adaptive reclosing method provided by the embodiment of the invention at least has the following beneficial effects: by comparing the modulus maximum value of the wavelet transformation of the initial voltage traveling wave and the first reflected traveling wave generated at the moment of closing the auxiliary contact of the circuit breaker, the fault types except the three-phase fault can be accurately identified, the transition resistance capability is strong, and the overvoltage impact caused by the fact that the three-phase reclosing is coincided with the permanent fault can be effectively prevented; in addition, the existing power system device can be utilized, and additional equipment does not need to be added.
According to some embodiments of the invention, the method of controlling the closing of the auxiliary contact comprises: and if three-phase tripping is detected, sending a closing instruction after the first reclosing time, and controlling the auxiliary contact to be closed.
According to some embodiments of the invention, the method for collecting the voltage traveling wave by the voltage traveling wave measuring device comprises: setting the sampling frequency of the voltage traveling wave measuring device to be 100kHz, and setting the sampling time window length of the voltage traveling wave measuring device to be 10 ms.
According to some embodiments of the present invention, the method for determining the type of the line fault according to the first wavelet transform modulus maximum point and the second wavelet transform modulus maximum point comprises: acquiring a first ratio of the first wavelet modulus maximum to the second wavelet transformation maximum according to the first wavelet transformation modulus maximum point and the second wavelet transformation modulus maximum point; if the first ratio is less than 1, the line fault type is a transient fault; otherwise, the line fault type is a permanent fault.
According to some embodiments of the invention, the method of latching the main contact and opening the auxiliary contact according to the line fault type comprises: if the line fault type is a transient fault, sending a command to close the main contact, and enabling the auxiliary contact to be short-circuited and withdrawn; and if the line fault type is a permanent fault, sending a command to lock the main contact and disconnect the auxiliary contact.
According to some embodiments of the present invention, if the line fault is a transient fault, a difference between a time for instructing to close the main contact and a time for controlling to close the auxiliary contact is a first time difference, and a value range of the first time difference is greater than 10ms and not greater than 30 ms.
According to a second aspect embodiment of the invention, the three-phase adaptive reclosing device comprises: the monitoring control module is used for monitoring the state of a circuit breaker of parallel-connection type closing resistors arranged at two ends of a power transmission line, wherein the circuit breaker comprises a main contact, an auxiliary contact and a closing resistor, one end of the auxiliary contact is connected with one end of the closing resistor to form an auxiliary closing branch, the auxiliary closing branch is connected with the main contact in parallel, and the resistance of the closing resistor is adjusted to be equal to the line wave impedance of the power transmission line; the first processing module is used for detecting three-phase tripping of the circuit breaker and controlling the auxiliary contacts to be closed; the traveling wave acquisition module is used for being connected with a voltage traveling wave measurement device arranged on the power transmission line, controlling the voltage traveling wave measurement to acquire a voltage traveling wave generated by closing the auxiliary contact and switching on the switching-on resistor and receiving data of the voltage traveling wave; the wavelet analysis module is used for extracting a first wavelet transform mode maximum point of the voltage initial traveling wave and a second wavelet transform mode maximum point of the first reflection traveling wave according to the data of the voltage traveling wave based on wavelet analysis; and the second processing module is used for judging the line fault type according to the first wavelet transformation mode maximum value point and the second wavelet transformation mode maximum value point, locking the main contact and disconnecting the auxiliary contact according to the line fault type.
The three-phase self-adaptive reclosing device provided by the embodiment of the invention at least has the following beneficial effects: by comparing the modulus maximum values of the wavelet transformation of the initial voltage traveling wave and the first reflected traveling wave generated at the moment of closing the auxiliary contact of the circuit breaker, the fault types except the three-phase fault can be accurately identified, the transition resistance capability is strong, and the overvoltage impact caused by the fact that the three-phase reclosing is superposed on the permanent fault can be effectively prevented; in addition, the existing power system device can be utilized, and additional equipment does not need to be added.
According to some embodiments of the invention, the first processing module further comprises: the timing module is used for waiting for first reclosing time and sending a timing completion signal if the three-phase tripping of the circuit breaker is detected; and the first control module is used for sending a closing instruction according to the timing completion signal and controlling the auxiliary contact to be closed.
According to some embodiments of the invention, the traveling wave acquisition module comprises: and the sampling control module is used for setting the sampling frequency of the voltage traveling wave measuring device to be 100kHz and setting the sampling time window length of the voltage traveling wave measuring device to be 10 ms.
According to some embodiments of the invention, the second processing module comprises: the fault type judging module is used for acquiring a first ratio of a first wavelet modulus maximum value to a second wavelet transformation maximum value according to the first wavelet transformation modulus maximum value point and the second wavelet transformation modulus maximum value point, and if the first ratio is smaller than 1, judging that the line fault type is a transient fault; otherwise, judging the line fault type to be a permanent fault; the second control module is used for sending an instruction to close the main contact if the line fault type is a transient fault, and the auxiliary contact is withdrawn by short circuit; and if the line fault type is a permanent fault, sending a command to lock the main contact and disconnect the auxiliary contact.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic flow chart of a method according to an embodiment of the present invention;
FIG. 2 is an equivalent model of a double ended power transmission system;
fig. 3 is a schematic diagram of a circuit breaker with a parallel-type closing resistor;
FIG. 4 is an equivalent schematic diagram of a positive sequence loop at the moment of line coincidence;
FIG. 5 is a schematic view of a traveling wave voltage at a measurement point under transient fault;
FIG. 6 is a schematic view of a traveling wave voltage at a measurement point under a permanent fault;
FIG. 7 is a wavelet analysis result of the voltage at the measuring point under the transient fault in the method according to the embodiment of the present invention;
FIG. 8 shows the wavelet analysis of the voltage at the measurement point under permanent fault in the method according to the embodiment of the present invention;
fig. 9 is a transmission line simulation parameter table used in a simulation experiment of the method according to the embodiment of the present invention;
FIG. 10 is a diagram illustrating wavelet analysis of the measured point voltage under a permanent failure of phase A metallic grounding in a simulation experiment according to the method of the embodiment of the present invention;
FIG. 11 is a diagram of a wavelet analysis of the measured point voltage under an A-phase metallic grounding transient fault in a simulation experiment of a method of an embodiment of the present invention;
FIG. 12 is a diagram illustrating wavelet analysis of voltages at measurement points under permanent fault conditions of BC phase grounding through a 50 Ω resistor in a simulation experiment according to the method of the embodiment of the present invention;
FIG. 13 is a diagram illustrating wavelet analysis of the voltage at the measurement point under the transient fault of grounding of the BC phase through a 50 Ω resistor in a simulation experiment according to the method of the embodiment of the present invention;
FIG. 14 shows wavelet analysis results of voltages at measurement points under different fault types in a simulation experiment according to the method of the embodiment of the present invention;
FIG. 15 is a result of wavelet analysis of voltages at measurement points under different fault resistances for ABC phase-to-phase faults in a simulation experiment of the method of the embodiment of the present invention;
FIG. 16 shows the wavelet analysis result of the voltage at the measurement point under different fault resistances of the phase-C fault in the simulation experiment of the method according to the embodiment of the present invention;
FIG. 17 is a block diagram of the modules of the system of an embodiment of the present invention.
Reference numerals:
the system comprises a monitoring control module 100, a first processing module 200, a traveling wave acquisition module 300, a wavelet analysis module 400 and a second processing module 500; a timing module 210, a first control module 220; a sampling control module 310; a fault type judging module 510 and a second control module 520.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention and are not to be construed as limiting the present invention.
In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and more than, less than, more than, etc. are understood as excluding the present number, and more than, less than, etc. are understood as including the present number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
Referring to fig. 1, the method of an embodiment of the present invention is as follows. Firstly, the circuit breakers with parallel-connection type closing resistors are respectively arranged at two ends of a power transmission line, and referring to fig. 3, each circuit breaker comprises a main contact, an auxiliary contact and a closing resistor, one end of each auxiliary contact is connected with one end of each closing resistor to form an auxiliary closing branch, each auxiliary closing branch is connected with the corresponding main contact in parallel, and the resistance of each closing resistor is adjusted to be equal to the line wave impedance of the power transmission line; obviously, if the circuit breaker with the parallel-connection type closing resistor exists in the power transmission line, only the closing resistor needs to be adjusted. The state of the circuit breaker is monitored, three-phase tripping is detected, the closing of the auxiliary contact is controlled, and voltage traveling waves generated by switching on a switching-on resistor when the auxiliary contact is closed are collected through a voltage traveling wave measuring device arranged on the power transmission line. And then acquiring data of the voltage traveling wave, extracting a first wavelet transform mode maximum point of the voltage initial traveling wave and a second wavelet transform mode maximum point of the first reflection traveling wave based on wavelet analysis, judging the type of the line fault, locking the main contact and disconnecting the auxiliary contact according to the type of the line.
The embodiment of the invention is provided for the power transmission line without the shunt reactor, and the existing power system device can be utilized without adding extra equipment. By comparing the modulus maximum value of the wavelet transformation of the initial voltage traveling wave and the first reflected traveling wave generated in the moment of closing the auxiliary contact of the circuit breaker, the fault types except the three-phase fault can be accurately identified, a fixed threshold value can be used as a criterion, the transition resistance is high in capacity, and the overvoltage impact caused by the fact that the three-phase reclosing is coincided with the permanent fault is effectively avoided.
Fig. 2 shows an equivalent model of a double-ended power supply transmission system. When a short-circuit fault occurs to a line, so that three phases of circuit breakers at two ends are tripped, the traditional reclosing strategy is to put one end of the line into automatic three-phase reclosing, and the circuit breakers are reclosed after preset reclosing time is reached. If the coincidence is successful, the other end is synchronously switched on by detecting the voltage; otherwise, if the reclosing is unsuccessful, the breaker is opened again and the three-phase automatic reclosing is locked.
The method of the embodiment of the invention requires the following devices: (1) the voltage traveling wave measuring device is a measuring unit which is used for fault traveling wave ranging in a high-voltage power transmission system; (2) a circuit breaker with a closing resistor for reducing an operating overvoltage, which is generally used in conjunction with a circuit breaker, is schematically shown in fig. 4. When the breaker is switched on, the auxiliary contact is closed firstly, the main contact is closed after about 10-20 ms, and the auxiliary contact is withdrawn by short circuit. Therefore, the method of the embodiment of the invention can directly utilize the device of the existing power transmission line system without additionally adding a device.
The method of the embodiment of the invention uses a closing resistor equal to the line wave impedance. With reference to fig. 4, at the instant of coincidence of the auxiliary contacts of the circuit breaker, a voltage travelling wave is generated, whose magnitude is related to the potential e at the bus, passing through the closing resistorMSimilarly, when the voltage traveling wave reaches the traveling wave measuring device (namely between the closing resistor and the power transmission line), the refraction and reflection of the traveling wave cannot be generated because the closing resistor is consistent with the impedance of the line wave, and at the moment, u is reflected1＝eMThe voltage travelling wave will continue to propagate. If the line has transient fault and the fault disappears, the traveling wave is transmitted to the tail end of the line, reflection occurs at the moment, and the reflection coefficient is as follows:
at this time, the end of the line is open, so Z can be considered2When the reflection coefficient beta is 1, the reflection traveling wave is overlapped with the forward traveling wave when reaching the measuring point, so that the traveling wave voltage of the measuring point is multiplied, and at the moment, u is multiplied1＝2eMThe corresponding theoretical analysis is shown in fig. 5.
If the line has a permanent fault, the traveling wave is transmitted to the fault point and is reflected, and if the fault is a metallic grounding fault, the fault can be considered as Z2Approximately equal to 0, then the reflection isThe number beta is-1, so that the reflected traveling wave is overlapped with the forward traveling wave to cancel each other when the reflected traveling wave arrives at the measuring point, and u is equal to the forward traveling wave 10, the corresponding theoretical analysis is shown in fig. 6.
According to the method provided by the embodiment of the invention, wavelet analysis is used for extracting the wavelet transformation modulus maximum values of the voltage initial traveling wave and the first reflection traveling wave at the measuring point after the auxiliary contact of the breaker is closed, and the line fault property is determined by comparing the modulus maximum values of the voltage initial traveling wave and the first reflection traveling wave. As shown in fig. 7, when the line is switched on after the transient fault of the line is extinguished, the traveling wave of the voltage is extracted by performing wavelet analysis on the voltage at the measurement point, and it can be seen that the modal maximum of the initial traveling wave is smaller than that of the first reflected traveling wave, and the former is about half of the latter. As shown in fig. 8, when the permanent fault is closed, the voltage traveling wave extracted by performing wavelet analysis on the voltage at the measurement point is shown, and it can be seen that the modal maximum of the initial traveling wave is greater than the modal maximum of the first reflected traveling wave. The above results are consistent with theoretical analysis.
Aiming at the three-phase automatic reclosing of the power transmission line without a shunt reactor, the method provided by the embodiment of the invention comprises the following specific implementation steps of:
(1) the state of the circuit breakers at two ends of the line is monitored in real time, and when three-phase tripping of the circuit breakers at two ends is detected, the three-phase automatic reclosing module is put into use;
(2) and the timer of the three-phase automatic reclosing module is started, and when the preset reclosing time of the traditional reclosing is reached, a closing instruction is sent out to control the closing of the auxiliary contact of the circuit breaker.
(3) And collecting the voltage of a measuring point through a voltage traveling wave measuring device, wherein the sampling rate is 100kHz, the length of a sampling time window is 10ms, and the time is enough to collect the first reflected voltage traveling wave.
(4) And extracting the wavelet transform modulus maximum value of the initial traveling wave and the first reflection traveling wave of the voltage signal in the sampling time window of the measuring point by adopting wavelet transform.
(5) When the ratio of the wavelet transformation modulus maximum of the initial voltage traveling wave of the measuring point to the wavelet transformation modulus maximum of the first reflected voltage traveling wave is less than 1, the circuit can be judged to have transient fault, and the main contact of the circuit breaker is controlled to be closed at the moment; otherwise, the circuit can be judged to have a permanent fault, and the main contact of the locking circuit breaker is closed and exits the auxiliary contact.
The following presents a technical verification simulation analysis of an embodiment of the present invention. A power transmission system as shown in fig. 2 is built in an electromagnetic transient simulation system PSCAD. Wherein the voltage at two ends is set to be 220kV, and the phase angle difference is 20 degrees; the transmission line adopts the line parameters shown in FIG. 9, the length is 100km, and the impedance of the positive sequence wave is 394 omega through software calculation; the closing resistor of the circuit breaker adopts the same resistance value as the positive sequence wave impedance of the line. Assuming that a fault occurs in a middle point of a line when t is 0.2s, the duration time of the transient fault is 0.3s, and the reclosing set time is 0.7 s.
Fig. 10 and 11 show the wavelet analysis results of the measured point voltage of the a-phase metallic ground under permanent and transient faults. Fig. 12 and 13 show the wavelet analysis results of the measured point voltage under permanent and transient faults when the BC phase is grounded through a 50 Ω resistance. It can be seen from the figure that under the permanent fault, the modulus maximum value of the voltage initial traveling wave wavelet transformation is larger than the modulus maximum value of the first reflected traveling wave; transient fault conditions are reversed. Therefore, the nature of the fault can be determined using whether the ratio of the two modulo maxima is greater than 1.
Referring to fig. 14, an analysis result of the simulation experiment when the fault resistance is 0.1 Ω under different fault types is shown, and it can be seen that, in addition to the three-phase fault, the other types of fault properties can be accurately identified when the threshold is set to 1. In an actual power transmission line, the line fault types are mostly single-phase earth faults, then phase-to-phase faults and phase-to-phase earth faults, and three-phase faults account for a small part, so that the threshold adopted by the method is suitable for most line faults. In addition, when a three-phase permanent fault occurs, the analysis result of the modulus maximum ratio is less than 1, the permanent fault is judged as an instantaneous fault by the criterion of the invention so as to be switched on, which is the same as the traditional reclosing result, but the permanent fault can not be judged under the instantaneous fault.
Referring to fig. 15 and fig. 16, analysis results of the ABC three-phase fault and the BC phase-to-phase fault under different fault resistances are respectively given, and it can be seen that a modulus maximum ratio of the ABC three-phase fault and the BC phase-to-phase fault under the transient fault is not changed; and the ratio of the two under the permanent fault increases along with the increase of the fault resistance, so the method provided by the invention has strong transient resistance.
Referring to fig. 17, an apparatus of an embodiment of the present invention includes: the system comprises a monitoring control module 100, a first processing module 200, a traveling wave acquisition module 300, a wavelet analysis module 400 and a second processing module 500. The monitoring control module 100 is configured to monitor states of circuit breakers of parallel-connection type closing resistors arranged at two ends of the power transmission line, and adjust the resistance of the closing resistors to be equal to line wave impedance of the power transmission line; the circuit breaker with the parallel-connection type closing resistor, referring to fig. 3, comprises a main contact, an auxiliary contact and a closing resistor, wherein one end of the auxiliary contact is connected with one end of the closing resistor to form an auxiliary closing branch, and the auxiliary closing branch is connected with the main contact in parallel. A first processing module 200 for detecting a three-phase trip of the circuit breaker, controlling the closing of the auxiliary contacts, comprising: the timing module 210 is configured to wait for a first reclosing time and send a timing completion signal if three-phase tripping of the circuit breaker is detected, where the first reclosing time may be configured to be the same as a preset reclosing time of a conventional reclosing; and the first control module 220 is configured to send a close instruction after receiving the timing completion signal, and control the auxiliary contact to close. The traveling wave acquisition module 300 is used for being connected with a voltage traveling wave measurement device arranged on the power transmission line, controlling the voltage traveling wave measurement to acquire a voltage traveling wave generated by closing an auxiliary contact to switch on a switching-on resistor and receiving data of the voltage traveling wave; the traveling wave acquisition module 300 further includes a sampling control module 310, configured to set sampling parameters of the voltage traveling wave measurement apparatus: the sampling frequency was set to 100kHz and the sampling time window length was set to 10 ms. After the first control module 220 sends the close command, the traveling wave obtaining module 300 sets the collection parameters of the voltage traveling wave measurement device through the collection control module 310, and then receives the data of the voltage traveling wave. The wavelet analysis module 400 is configured to extract a first wavelet transform mode maximum point of the voltage initial traveling wave and a second wavelet transform mode maximum point of the first reflection traveling wave from the data of the voltage traveling wave based on wavelet analysis. And the second processing module 500 is configured to determine a line fault type according to the first wavelet transform mode maximum value point and the second wavelet transform mode maximum value point, and lock the main contact and disconnect the auxiliary contact according to the line fault type. The second process module 500 includes: a fault type determining module 510, configured to obtain a first ratio of the first wavelet modulus maximum to the second wavelet transformation maximum according to the first wavelet transformation modulus maximum and the second wavelet transformation modulus maximum, and determine that the line fault type is an instantaneous fault if the first ratio is smaller than 1; otherwise, judging the type of the line fault as a permanent fault; the second control module 520 is configured to send an instruction to close the main contact if the line fault type is an instantaneous fault, and the auxiliary contact is short-circuited and exits when the main contact is closed; if the line fault type is a permanent fault, an instruction is sent to lock the main contact and disconnect the auxiliary contact.
Although specific embodiments have been described herein, those of ordinary skill in the art will recognize that many other modifications or alternative embodiments are equally within the scope of this disclosure. For example, any of the functions and/or processing capabilities described in connection with a particular device or component may be performed by any other device or component. In addition, while various illustrative implementations and architectures have been described in accordance with embodiments of the present disclosure, those of ordinary skill in the art will recognize that many other modifications of the illustrative implementations and architectures described herein are also within the scope of the present disclosure.
Certain aspects of the present disclosure are described above with reference to block diagrams and flowchart illustrations of systems, methods, systems, and/or computer program products according to example embodiments. It will be understood that one or more blocks of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, respectively, can be implemented by executing computer-executable program instructions. Also, according to some embodiments, some blocks of the block diagrams and flow diagrams may not necessarily be performed in the order shown, or may not necessarily be performed in their entirety. In addition, additional components and/or operations beyond those shown in the block diagrams and flow diagrams may be present in certain embodiments.
Accordingly, blocks of the block diagrams and flowchart illustrations support combinations of means for performing the specified functions, combinations of elements or steps for performing the specified functions and program instruction means for performing the specified functions. It will also be understood that each block of the block diagrams and flowchart illustrations, and combinations of blocks in the block diagrams and flowchart illustrations, can be implemented by special purpose hardware-based computer systems that perform the specified functions, elements or steps, or combinations of special purpose hardware and computer instructions.
The program modules, applications, etc. described herein may include one or more software components, including, for example, software objects, methods, data structures, etc. Each such software component may include computer-executable instructions that, in response to execution, cause at least a portion of the functionality described herein (e.g., one or more operations of the illustrative methods described herein) to be performed.
The software components may be encoded in any of a variety of programming languages. An exemplary programming language may be a low-level programming language, such as assembly language associated with a particular hardware architecture and/or operating system platform. Software components that include assembly language instructions may need to be converted by an assembler program into executable machine code prior to execution by a hardware architecture and/or platform. Another exemplary programming language may be a higher level programming language, which may be portable across multiple architectures. Software components that include higher level programming languages may need to be converted to an intermediate representation by an interpreter or compiler before execution. Other examples of programming languages include, but are not limited to, a macro language, a shell or command language, a job control language, a scripting language, a database query or search language, or a report writing language. In one or more exemplary embodiments, a software component containing instructions of one of the above programming language examples may be executed directly by an operating system or other software component without first being converted to another form.
The software components may be stored as files or other data storage constructs. Software components of similar types or related functionality may be stored together, such as in a particular directory, folder, or library. Software components may be static (e.g., preset or fixed) or dynamic (e.g., created or modified at execution time).
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.
Claims (3)
1. A three-phase self-adaptive reclosing method is characterized by comprising the following steps:
the circuit breaker is characterized in that the two ends of a power transmission line are respectively provided with a circuit breaker of a parallel-connection type closing resistor, the circuit breaker comprises a main contact, an auxiliary contact and a closing resistor, one end of the auxiliary contact is connected with one end of the closing resistor to form an auxiliary closing branch, the auxiliary closing branch is connected with the main contact in parallel, and the resistance of the closing resistor is adjusted to be equal to the line wave impedance of the power transmission line;
monitoring the state of the circuit breaker, detecting three-phase tripping, controlling the auxiliary contact to be closed, and collecting voltage traveling waves generated when the auxiliary contact is closed and the closing resistor is switched on through a voltage traveling wave measuring device arranged on the power transmission line;
extracting a first wavelet transformation mode maximum point of a voltage initial traveling wave and a second wavelet transformation mode maximum point of a first reflection traveling wave in the voltage traveling wave based on wavelet analysis, judging a line fault type according to the first wavelet transformation mode maximum point and the second wavelet transformation mode maximum point, and locking the main contact and disconnecting the auxiliary contact according to the line fault type;
wherein the method of controlling the closing of the auxiliary contact comprises: if three-phase tripping is detected, sending a closing instruction after the first reclosing time to control the auxiliary contact to be closed;
the method for acquiring the voltage traveling wave through the voltage traveling wave measuring device comprises the following steps: setting the sampling frequency of the voltage traveling wave measuring device to be 100kHz, and setting the length of a sampling time window of the voltage traveling wave measuring device to be 10 ms;
the method for judging the type of the line fault according to the first wavelet transform mode maximum value point and the second wavelet transform mode maximum value point comprises the following steps:
acquiring a first ratio of the first wavelet modulus maximum to the second wavelet transformation maximum according to the first wavelet transformation modulus maximum point and the second wavelet transformation modulus maximum point;
if the first ratio is less than 1, the line fault type is a transient fault; otherwise, the line fault type is a permanent fault
The method of latching the main contacts and opening the auxiliary contacts according to the line fault type comprises:
if the line fault type is a transient fault, sending a command to close the main contact, and enabling the auxiliary contact to be short-circuited and withdrawn;
and if the line fault type is a permanent fault, sending a command to lock the main contact and disconnect the auxiliary contact.
2. The three-phase adaptive reclosing method according to claim 1, wherein if the line fault is a transient fault, a difference between a time for sending a command to close the main contact and a time for controlling the auxiliary contact to close is a first time difference, and a value range of the first time difference is greater than 10ms and not greater than 30 ms.
3. The utility model provides a three-phase self-adaptation reclosing device which characterized in that includes:
the monitoring control module is used for monitoring the state of a circuit breaker of parallel-connection type closing resistors arranged at two ends of a power transmission line, wherein the circuit breaker comprises a main contact, an auxiliary contact and a closing resistor, one end of the auxiliary contact is connected with one end of the closing resistor to form an auxiliary closing branch, the auxiliary closing branch is connected with the main contact in parallel, and the resistance of the closing resistor is adjusted to be equal to the line wave impedance of the power transmission line;
the first processing module is used for detecting the three-phase tripping of the circuit breaker and controlling the auxiliary contacts to be closed;
the traveling wave acquisition module is used for being connected with a voltage traveling wave measurement device arranged on the power transmission line, controlling the voltage traveling wave measurement to acquire a voltage traveling wave generated by closing the auxiliary contact and switching on the switching-on resistor and receiving data of the voltage traveling wave;
the wavelet analysis module is used for extracting a first wavelet transform mode maximum point of the voltage initial traveling wave and a second wavelet transform mode maximum point of the first reflection traveling wave according to the data of the voltage traveling wave based on wavelet analysis;
the second processing module is used for judging the line fault type according to the first wavelet transformation mode maximum value point and the second wavelet transformation mode maximum value point, locking the main contact and disconnecting the auxiliary contact according to the line fault type;
wherein the first processing module further comprises:
the timing module is used for waiting for first reclosing time and sending a timing completion signal if the three-phase tripping of the circuit breaker is detected;
the first control module is used for sending a closing instruction according to the timing completion signal and controlling the auxiliary contact to be closed;
the traveling wave acquisition module includes: the sampling control module is used for setting the sampling frequency of the voltage traveling wave measuring device to be 100kHz and setting the sampling time window length of the voltage traveling wave measuring device to be 10 ms;
the second processing module comprises:
the fault type judging module is used for acquiring a first ratio of a first wavelet modulus maximum value to a second wavelet transformation maximum value according to the first wavelet transformation modulus maximum value point and the second wavelet transformation modulus maximum value point, and if the first ratio is smaller than 1, judging that the line fault type is a transient fault; otherwise, judging the line fault type to be a permanent fault;
the second control module is used for sending an instruction to close the main contact if the line fault type is a transient fault, and the auxiliary contact is withdrawn by short circuit; and if the line fault type is a permanent fault, sending a command to lock the main contact and disconnect the auxiliary contact.
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| CN101316036A (en) * | 2008-07-16 | 2008-12-03 | 天津大学 | Self-adapting three-phase reclosure decision method of ultra-high voltage electric power line with shunt reactor |
| WO2010043014A1 (en) * | 2008-10-13 | 2010-04-22 | Universidade Estadual De Campinas - Unicamp | Fast three-phase reclosing method in shunt reactor compensated transmission lines |
| CN110768221A (en) * | 2019-10-22 | 2020-02-07 | 华中科技大学 | Adaptive reclosing method for overhead flexible direct-current power grid |
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| CN106711925B (en) * | 2016-12-27 | 2019-12-10 | 新疆大学 | self-adaptive three-phase reclosing lock for single loop outgoing line of wind power plant and method thereof |
| CN108390354A (en) * | 2018-02-11 | 2018-08-10 | 国网陕西省电力公司电力科学研究院 | Adaptive reclosing switch and the feeder automation control method based on the switch |
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| CN101316036A (en) * | 2008-07-16 | 2008-12-03 | 天津大学 | Self-adapting three-phase reclosure decision method of ultra-high voltage electric power line with shunt reactor |
| WO2010043014A1 (en) * | 2008-10-13 | 2010-04-22 | Universidade Estadual De Campinas - Unicamp | Fast three-phase reclosing method in shunt reactor compensated transmission lines |
| CN110768221A (en) * | 2019-10-22 | 2020-02-07 | 华中科技大学 | Adaptive reclosing method for overhead flexible direct-current power grid |
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