CN112242695B - Relay protection data synchronization method and device based on wireless communication - Google Patents
Relay protection data synchronization method and device based on wireless communication Download PDFInfo
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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
- H02H7/261—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 involving signal transmission between at least two stations
- H02H7/263—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 involving signal transmission between at least two stations involving transmissions of measured values
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Abstract
A relay protection data synchronization method and device based on wireless communication are disclosed, the method comprises: the synchronous sampling of the data at the two ends of the distribution network line is realized by adding cycle sequence number information where the sampling points are located in the current sampling data at the home end and the opposite end and comparing the cycle sequence number information in the current sampling data at the two ends with the waveform characteristics corresponding to the cycle sequence number information. By the method and the device provided by the embodiment of the invention, under the condition of not depending on an external clock signal, the synchronous sampling of data at two ends of a distribution network line can be realized, the synchronization performance is not influenced in a wireless channel delay jitter range, the problem of synchronous sampling of protection data at two ends in distribution network differential protection after a wireless communication technology is adopted is effectively solved, and the reliable support is provided for a wireless distribution network protection system.
Description
Technical Field
The invention relates to the technical field of relay protection of power systems, in particular to a relay protection data synchronization method and device based on wireless communication.
Background
At present, single-end-quantity protection is mainly used for protecting a power distribution network, requirements on power utilization reliability and power quality are continuously improved along with continuous improvement of new energy access proportion and gradual complexity of a network topological structure, and the requirements on speed and selectivity cannot be simultaneously met in the conventional single-end-quantity power distribution network protection.
The multi-end protection such as differential protection, regional protection and the like fully utilizes a communication channel to expand the information acquisition range, has the advantages of sensitivity, reliability, high action speed and the like, can adapt to various complex fault running states, and effectively improves the power grid protection level.
The differential protection principle needs to calculate the differential current by using the sampling data at the same time at two ends of the line, so that the synchronous acquisition of the data at the two ends of the line is a necessary condition for realizing the differential protection. The traditional optical fiber differential protection generally utilizes a ping-pong principle to adjust sampling time or correct a clock, so as to realize the synchronization of sampling data. The differential protection adopting wireless communication technologies such as 5G and the like has the problems of time delay jitter, asymmetrical transceiving route, unequal channel bidirectional data transmission time delay and the like, and the traditional data synchronization protection method based on the ping-pong principle is not suitable any more.
Disclosure of Invention
In view of this, the present invention provides a relay protection data synchronization method and apparatus based on wireless communication, and aims to solve the problem in the related art that synchronous acquisition of data at two ends cannot be achieved by adopting differential protection after wireless communication.
In a first aspect, an embodiment of the present invention provides a relay protection data synchronization method based on wireless communication, including: respectively sampling current of the local terminal and the opposite terminal by adopting fixed frequency to obtain current sampling data of the local terminal and current sampling data of the opposite terminal; the current sampling data of the local terminal is sent to the opposite terminal through a wireless communication link so that the opposite terminal can carry out current sampling according to the current sampling data of the local terminal at the same time, and the current sampling data sent from the opposite terminal through the wireless communication link is received at the local terminal; the current sampling data of the local end and the current sampling data of the opposite end both comprise at least one cycle, the waveform of each cycle comprises a sampling point changing from positive to negative zero crossing point and a sampling point changing from negative to positive zero crossing point, and each data frame of the current sampling data of the local end and the current sampling data of the opposite end comprises cycle serial number information of the sampling point; respectively extracting cycle sequence number information in the current sampling data of the local terminal and the current sampling data of the opposite terminal and waveform characteristics corresponding to each cycle sequence number information; taking the cycle at the preset reference sampling time of the opposite end as a reference cycle, and sequentially comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end to determine the reference cycle of the local end; and determining the sampling time of the local terminal in the reference cycle of the local terminal according to the waveform characteristics of the preset reference sampling time of the opposite terminal so as to realize the data synchronization of the local terminal and the opposite terminal.
Further, the sequentially comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end to determine the reference cycle of the local end includes: and sequentially judging whether the cycle number information of the local end is the same as the cycle number of the reference cycle of the opposite end according to a preset sequence, and if so, determining the local end cycle with the same cycle number information as the reference cycle of the local end.
Further, the method comprises the following steps in a preset sequence: and according to the sequence of cycle sequence number information in the buffer area of the local terminal protection device from back to front.
Further, the determining the sampling time of the local terminal in the reference cycle of the local terminal according to the waveform characteristics of the preset reference sampling time of the opposite terminal includes: and selecting the sampling time corresponding to the waveform with the same waveform characteristics as the preset reference sampling time of the opposite end as the sampling time of the local end from the reference cycle of the local end.
Further, in the reference cycle of the local terminal, selecting a sampling time corresponding to a waveform with the same waveform characteristics as the preset reference sampling time of the opposite terminal as the sampling time of the local terminal, including:
if the preset reference sampling time of the opposite end is the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive, the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive is selected as the sampling time of the local end in the reference cycle of the local end.
Further, before the current sampling with the fixed frequency, the method further includes: and respectively calibrating the time information of the local terminal and the opposite terminal according to the time information acquired from the base station through the wireless communication link.
In a second aspect, an embodiment of the present invention further provides a relay protection data synchronization apparatus based on wireless communication, including: the data sampling unit is used for respectively sampling current of the local terminal and the opposite terminal by adopting fixed frequency so as to obtain current sampling data of the local terminal and current sampling data of the opposite terminal; the data receiving and sending unit is used for sending the current sampling data of the local terminal to the opposite terminal through the wireless communication link so as to enable the opposite terminal to carry out current sampling according to the current sampling data of the local terminal at the synchronous moment, and receiving the current sampling data sent by the opposite terminal through the wireless communication link at the local terminal; the current sampling data of the local end and the current sampling data of the opposite end both comprise at least one cycle, the waveform of each cycle comprises a sampling point changing from positive to negative zero crossing point and a sampling point changing from negative to positive zero crossing point, and each data frame of the current sampling data of the local end and the current sampling data of the opposite end comprises cycle serial number information of the sampling point; the data extraction unit is used for respectively extracting cycle number information in the current sampling data of the local terminal and the current sampling data of the opposite terminal and waveform characteristics corresponding to each cycle number information; the reference cycle determining unit is used for taking the cycle at the preset reference sampling time of the opposite end as a reference cycle, sequentially comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end, and determining the reference cycle of the local end; and the sampling moment determining unit is used for determining the sampling moment of the local terminal in the reference cycle of the local terminal according to the waveform characteristics of the preset reference sampling moment of the opposite terminal so as to realize the data synchronization of the local terminal and the opposite terminal.
Further, the sequentially comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end to determine the reference cycle of the local end includes: and sequentially judging whether the cycle number information of the local end is the same as the cycle number of the reference cycle of the opposite end according to a preset sequence, and if so, determining the local end cycle with the same cycle number information as the reference cycle of the local end.
Further, the method comprises the following steps in a preset sequence: and according to the sequence of cycle sequence number information in the buffer area of the local terminal protection device from back to front.
Further, the determining the sampling time of the local terminal in the reference cycle of the local terminal according to the waveform characteristics of the preset reference sampling time of the opposite terminal includes: and selecting the sampling time corresponding to the waveform with the same waveform characteristics as the preset reference sampling time of the opposite end as the sampling time of the local end from the reference cycle of the local end.
Further, in the reference cycle of the local terminal, selecting a sampling time corresponding to a waveform with the same waveform characteristics as the preset reference sampling time of the opposite terminal as the sampling time of the local terminal, including: if the preset reference sampling time of the opposite end is the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive, the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive is selected as the sampling time of the local end in the reference cycle of the local end.
Further, the apparatus further comprises: and the time calibration unit is used for respectively calibrating the time information of the local terminal and the opposite terminal according to the time information acquired from the base station through the wireless communication link before the current sampling is respectively carried out on the local terminal and the opposite terminal by adopting the fixed frequency.
In a third aspect, an embodiment of the present invention further provides a computer-readable storage medium, on which a computer program is stored, where the computer program is used, when executed by a processor, to implement the method provided in the embodiments of the present invention.
According to the relay protection data synchronization method and device based on wireless communication provided by the embodiment of the invention, the cycle sequence number information of the sampling point is added in the current sampling data, and based on the cycle sequence number information and the waveform characteristics corresponding to the cycle sequence number information, under the condition of not depending on a clock signal, the synchronous sampling of data at two ends of a distribution network line is realized, the synchronization performance is not influenced in a wireless channel delay jitter range, the problem of synchronous sampling of protection data at two ends in distribution network differential protection after a wireless communication technology is adopted is effectively solved, and reliable support is provided for a wireless distribution network protection system.
Drawings
FIG. 1 illustrates an exemplary system architecture in which embodiments of the invention may be applied;
fig. 2 shows an exemplary flowchart of a relay protection data synchronization method based on wireless communication according to an embodiment of the present invention;
FIG. 3 illustrates an exemplary current waveform plot of current sample data at the local terminal or current sample data at the opposite terminal;
FIG. 4 illustrates an exemplary current waveform at the preset reference sampling instant of the opposite terminal;
FIG. 5 illustrates a schematic diagram of selecting sampling instants for a local end, according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a relay protection data synchronization device based on wireless communication according to an embodiment of the present invention.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
Referring to FIG. 1, an exemplary system architecture 100 is shown in which embodiments of the present invention may be employed.
As shown in fig. 1, the system architecture 100 may include an M-side protection device 101, an N-side protection device 102, base stations 103, 104, and a wireless communication network 105. The wireless communication network 105 is used to provide a medium of communication links between the M-side protection device 101, the N-side protection device 102, and the base stations 103 and 104, and is also used to provide a medium of communication links between the base station 103 and the base station 104. The wireless communication network 105 may include various wireless communication types, such as 2G, 3G, 4G, 5G, satellite communication, and so forth.
The M-side protection device 101 and the N-side protection device 102 may be connected to the same base station 103 through the wireless communication network 105 for data interaction, or may be connected to the base station 103 and the base station 104 through the wireless communication network 105 for data interaction.
The M-terminal protection device 101 and the N-terminal protection device 102 may be distribution network line protection devices that execute various instructions such as current sampling and current sampling data interaction, processing, synchronization, differential protection, and the like. It will be appreciated that one protection device may execute one or more instructions, and that the same instruction may be executed by multiple protection devices.
It should be understood that the number of protection devices, base stations and wireless communication networks in fig. 1 is merely illustrative. There may be any number of protection devices, base stations, and wireless communication networks, as desired for an implementation.
Fig. 2 shows an exemplary flowchart of a relay protection data synchronization method based on wireless communication according to an embodiment of the present invention.
As shown in fig. 2, the method includes:
step S201: and respectively carrying out current sampling on the local terminal and the opposite terminal by adopting fixed frequency so as to obtain current sampling data of the local terminal and current sampling data of the opposite terminal.
In the embodiment of the invention, the protection devices of the local end and the opposite end of the distribution network line can respectively perform current sampling by adopting consistent and fixed frequency so as to obtain current sampling data of the local end and the opposite end with consistent and fixed frequency.
Step S202: the current sampling data of the local terminal is sent to the opposite terminal through the wireless communication link so that the opposite terminal can carry out current sampling according to the current sampling data of the local terminal at the same time, and the current sampling data sent from the opposite terminal through the wireless communication link is received at the local terminal; the current sampling data of the local terminal and the current sampling data of the opposite terminal both comprise at least one cycle, the waveform of each cycle comprises a sampling point changing from positive to negative zero crossing point and a sampling point changing from negative to positive zero crossing point, and each data frame of the current sampling data of the local terminal and the current sampling data of the opposite terminal comprises cycle number information of the sampling point.
In the embodiment of the invention, the current sampling data interaction can be carried out by the local terminal and the opposite terminal protection devices through the wireless communication link. Further, the wireless communication link is a high-speed wireless communication link. Further, the high-speed wireless communication link is a 5G link. Fig. 3 illustrates an exemplary current waveform diagram of current sample data at the local terminal or current sample data at the opposite terminal. As shown in fig. 3, the communication delay between two adjacent distribution network protection devices (between the local terminal and the opposite terminal protection device) according to the 5G link is within 40ms, the current sampling data may use four cycles (80 ms) as a period, the waveform of each cycle (20 ms) includes a sampling point a changing from negative to positive zero crossing point and a sampling point b changing from positive to negative zero crossing point, the cycle number information of the sampling point is added in each data frame, the first cycle adds 00, the second cycle adds 01, the third cycle adds 10, the fourth cycle adds 11, and the fifth cycle adds 00 … …. It should be noted that the cycle number information format is not unique, and may be a cycle number according to a certain cycle as a period, as shown in the embodiment of fig. 3; the cycles may be numbered in a specific order, for example, the cycles are numbered in an increasing order, and the overflow is automatically circulated, wherein the first cycle is 000000000, the second cycle is 000000001, … …, the 1024 th cycle is 111111111, and the 1025 th cycle is 000000000.
Step S203: and respectively extracting cycle sequence number information in the current sampling data of the local terminal and the current sampling data of the opposite terminal and waveform characteristics corresponding to each cycle sequence number information.
In the embodiment of the invention, the cycle number information in the current sampling data of the local terminal and the current sampling data of the opposite terminal and the waveform characteristics corresponding to each cycle number information are respectively extracted for comparison in the subsequent steps.
Step S204: and taking the cycle at the preset reference sampling moment of the opposite end as a reference cycle, and sequentially comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end to determine the reference cycle of the local end.
In the embodiment of the invention, the preset reference sampling time of the opposite terminal can be preset and selected according to requirements, and the sampling time corresponding to any sampling point in any cycle in the current sampling data of the opposite terminal can be selected as the preset reference sampling time. It should be noted that there may be more than one preset reference sampling time of the opposite end, and if there are more than one preset reference sampling times of the opposite end, the sequence of each preset reference sampling time may be preset; if the current sampling data frame number corresponding to the first preset reference sampling moment is not continuous with the previous frame number, that is, packet loss occurs, the next preset reference sampling moment is the preset reference sampling moment of the opposite end, so that the situation that data at two ends cannot be synchronized due to packet loss is avoided.
Fig. 4 shows an exemplary current waveform diagram for the preset reference sampling instant for the opposite end. As shown in fig. 4, the preset reference sampling time of the opposite end may include four sampling times: sampling time t corresponding to the first sampling point after the first cycle 00 changes from negative to positive zero crossing point0And the sampling time t corresponding to the first sampling point after the positive-to-negative zero crossing point of the first cycle 002And the sampling time t corresponding to the highest sampling point in the first cycle 001And the sampling time t corresponding to the lowest sampling point in the first cycle 003The four sampling moments are according to t0→t2→t1→t3The sequence of the steps is set; if t0If the frame number of the corresponding current sampling data is not continuous with the frame number of the previous frame, t is used2For presetting a reference sampling time, if t2Corresponding current sampling data frame number and previousIf the frame number is not continuous, t is used1And selecting proper preset reference sampling time for the preset reference sampling time … … according to a preset sequence, so as to avoid the condition that data at two ends cannot be synchronized due to data packet loss.
Further, in step S204, sequentially comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end, and determining the reference cycle of the local end includes:
and sequentially judging whether the cycle number information of the local end is the same as the cycle number of the reference cycle of the opposite end according to a preset sequence, and if so, determining the local end cycle with the same cycle number information as the reference cycle of the local end.
In the embodiment of the present invention, the preset sequence may be any sequence from front to back, from back to front, from the middle to front, and the like according to the cycle number information in the buffer of the local protection device. Further, the method comprises the following steps in a preset sequence: and according to the sequence of cycle sequence number information in the buffer area of the local terminal protection device from back to front.
Comparing and judging the cycle number information of the local end with the cycle number of the reference cycle of the opposite end in sequence until the cycle number information of the local end is the same as the cycle number information of the reference cycle of the opposite end, and determining the cycle corresponding to the same cycle number information as the reference cycle of the local end.
Step S205: and determining the sampling time of the local terminal in the reference cycle of the local terminal according to the waveform characteristics of the preset reference sampling time of the opposite terminal so as to realize the data synchronization of the local terminal and the opposite terminal.
In the embodiment of the present invention, the two-terminal current sampling data synchronization process may be performed every n (n is a positive integer) cycles.
It should be appreciated that in other embodiments of the present invention, if the sampling rate is lower than the predetermined threshold, the data synchronization may be performed in conjunction with an interpolation algorithm.
In other embodiments of the present invention, when a line fails, the protection device detects a current break amount, and at this time, data synchronization is suspended, and the protection criterion calculation is performed by delaying the last synchronization result, and data synchronization is recovered when the current break amount disappears.
Further, step S205 includes:
and selecting the sampling time corresponding to the waveform with the same waveform characteristics as the preset reference sampling time of the opposite end as the sampling time of the local end in the reference cycle of the local end so as to realize the data synchronization of the local end and the opposite end.
In the embodiment of the invention, the waveform characteristics of the preset reference sampling time of the opposite end are compared in the reference cycle of the local end, and the sampling time corresponding to the waveform with the same waveform characteristics is obtained as the sampling time of the local end, so that the current sampling data of the local end and the current sampling data of the opposite end are synchronized, and reliable protection criteria can be provided for subsequent differential protection.
Further, in the reference cycle of the local terminal, selecting the sampling time corresponding to the waveform with the same waveform characteristics as the preset reference sampling time of the opposite terminal as the sampling time of the local terminal, including:
if the preset reference sampling time of the opposite end is the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive, the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive is selected as the sampling time of the local end in the reference cycle of the local end.
Fig. 5 shows a schematic diagram of selecting sampling instants of a local end according to an embodiment of the present invention. As shown in fig. 5, if the sampling time t corresponding to the first sampling point after the negative-to-positive zero crossing point in the first cycle 00 of the N terminalN0For presetting the reference sampling time, the reference cycle of the M end can be obtained as the first cycle 00 according to the comparison of the cycle number information, and then the preset reference sampling time t of the N end is usedN0Correspondingly selecting the sampling time t corresponding to the first sampling point after the zero crossing point changed from negative to positive in the first cycle 00 of the M endM0The sampling time of the M end is obtained, so that the current sampling data of the M end and the current sampling data of the N end are synchronized. Similarly, if the sampling time t corresponding to the first sampling point after the negative-to-positive zero crossing point in the second cycle 01 of the N terminalN1For presetting a reference sampling moment, then obtainingThe sampling time t corresponding to the first sampling point after the negative-to-positive zero crossing point in the second cycle 01 to the M endM1The sampling time of the M end is obtained, so that the current sampling data of the M end and the current sampling data of the N end are synchronized.
In the above embodiment, the cycle number information where the sampling point is located is added to the current sampling data, and based on the cycle number information and the waveform characteristics corresponding to the cycle number information, synchronous sampling of data at two ends of the distribution network line is realized without depending on a clock signal, and the synchronization performance is not affected in the wireless channel delay jitter range, so that the problem of synchronous sampling of protection data at two ends in distribution network differential protection after a wireless communication technology is adopted is effectively solved, and reliable support is provided for a wireless distribution network protection system.
Further, before step S201, the method further includes:
step S200: and respectively calibrating the time information of the local terminal and the opposite terminal according to the time information acquired from the base station through the wireless communication link.
In the embodiment of the invention, the protection devices of the home terminal and the opposite terminal are powered on for the first time, a wireless communication link is established, high-precision time information is obtained from a base station through the wireless communication link, and the time information of the home terminal and the time information of the opposite terminal are respectively calibrated according to the time information, so that the synchronization of initial sampling time is realized.
In the embodiment, the time calibration is completed in advance according to the base station before the current sampling at the two ends, so that the accuracy of the current sampling moment can be improved, and the reliability of the subsequent data synchronization at the two ends is improved.
It should be noted that, during or after the data synchronization between the two terminals, if the wireless communication link is abnormal or interrupted and is recovered again, the protection device needs to execute steps S200-205 again, and after the time information of the two terminals is recalibrated, the current sampling data synchronization between the two terminals is performed again.
Fig. 6 is a schematic structural diagram of a relay protection data synchronization device based on wireless communication according to an embodiment of the present invention.
As shown in fig. 6, the apparatus includes:
the data sampling unit 601 is configured to perform current sampling on the local terminal and the opposite terminal respectively by using a fixed frequency, so as to obtain current sampling data of the local terminal and current sampling data of the opposite terminal.
In the embodiment of the invention, the protection devices of the local end and the opposite end of the distribution network line can respectively perform current sampling by adopting consistent and fixed frequency so as to obtain current sampling data of the local end and the opposite end with consistent and fixed frequency.
A data transceiver unit 602, configured to send current sampling data of a home terminal to an opposite terminal through a wireless communication link, so that a time when the opposite terminal performs current sampling according to the current sampling data of the home terminal is synchronous, and receive, at the home terminal, the current sampling data sent by the opposite terminal through the wireless communication link; the current sampling data of the local terminal and the current sampling data of the opposite terminal both comprise at least one cycle, the waveform of each cycle comprises a sampling point changing from positive to negative zero crossing point and a sampling point changing from negative to positive zero crossing point, and each data frame of the current sampling data of the local terminal and the current sampling data of the opposite terminal comprises cycle number information of the sampling point.
In the embodiment of the invention, the current sampling data interaction can be carried out by the local terminal and the opposite terminal protection devices through the wireless communication link. Further, the wireless communication link is a high-speed wireless communication link. Further, the high-speed wireless communication link is a 5G link. Fig. 3 illustrates an exemplary current waveform diagram of current sample data at the local terminal or current sample data at the opposite terminal. As shown in fig. 3, the communication delay between two adjacent distribution network protection devices (between the local terminal and the opposite terminal protection device) according to the 5G link is within 40ms, the current sampling data may use four cycles (80 ms) as a period, the waveform of each cycle (20 ms) includes a sampling point a changing from negative to positive zero crossing point and a sampling point b changing from positive to negative zero crossing point, the cycle number information of the sampling point is added in each data frame, the first cycle adds 00, the second cycle adds 01, the third cycle adds 10, the fourth cycle adds 11, and the fifth cycle adds 00 … …. It should be noted that the cycle number information format is not unique, and may be a cycle number according to a certain cycle as a period, as shown in the embodiment of fig. 3; the cycles may be numbered in a specific order, for example, the cycles are numbered in an increasing order, and the overflow is automatically circulated, wherein the first cycle is 000000000, the second cycle is 000000001, … …, the 1024 th cycle is 111111111, and the 1025 th cycle is 000000000.
The data extracting unit 603 is configured to extract cycle number information in the current sampling data of the local terminal and the current sampling data of the opposite terminal, and waveform features corresponding to each cycle number information.
In the embodiment of the invention, the cycle number information in the current sampling data of the local terminal and the current sampling data of the opposite terminal and the waveform characteristics corresponding to each cycle number information are respectively extracted for comparison in the subsequent steps.
The reference cycle determining unit 604 is configured to take a cycle where a preset reference sampling time of the opposite end is located as a reference cycle, sequentially compare the cycle number information of the local end with the cycle number of the reference cycle of the opposite end, and determine the reference cycle of the local end.
In the embodiment of the invention, the preset reference sampling time of the opposite terminal can be preset and selected according to requirements, and the sampling time corresponding to any sampling point in any cycle in the current sampling data of the opposite terminal can be selected as the preset reference sampling time. It should be noted that there may be more than one preset reference sampling time of the opposite end, and if there are more than one preset reference sampling times of the opposite end, the sequence of each preset reference sampling time may be preset; if the current sampling data frame number corresponding to the first preset reference sampling moment is not continuous with the previous frame number, that is, packet loss occurs, the next preset reference sampling moment is the preset reference sampling moment of the opposite end, so that the situation that data at two ends cannot be synchronized due to packet loss is avoided.
Fig. 4 shows an exemplary current waveform diagram for the preset reference sampling instant for the opposite end. As shown in fig. 4, the preset reference sampling time of the opposite end may include four sampling times: sampling corresponding to the first sampling point after the first cycle 00 changes from negative to positive zero crossing pointTime t0And the sampling time t corresponding to the first sampling point after the positive-to-negative zero crossing point of the first cycle 002And the sampling time t corresponding to the highest sampling point in the first cycle 001And the sampling time t corresponding to the lowest sampling point in the first cycle 003The four sampling moments are according to t0→t2→t1→t3The sequence of the steps is set; if t0If the frame number of the corresponding current sampling data is not continuous with the frame number of the previous frame, t is used2For presetting a reference sampling time, if t2If the frame number of the corresponding current sampling data is not continuous with the frame number of the previous frame, t is used1And selecting proper preset reference sampling time for the preset reference sampling time … … according to a preset sequence, so as to avoid the condition that data at two ends cannot be synchronized due to data packet loss.
Further, comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end in sequence to determine the reference cycle of the local end, including:
and sequentially judging whether the cycle number information of the local end is the same as the cycle number of the reference cycle of the opposite end according to a preset sequence, and if so, determining the local end cycle with the same cycle number information as the reference cycle of the local end.
In the embodiment of the present invention, the preset sequence may be any sequence from front to back, from back to front, from the middle to front, and the like according to the cycle number information in the buffer of the local protection device. Further, the method comprises the following steps in a preset sequence: and according to the sequence of cycle sequence number information in the buffer area of the local terminal protection device from back to front.
Comparing and judging the cycle number information of the local end with the cycle number of the reference cycle of the opposite end in sequence until the cycle number information of the local end is the same as the cycle number information of the reference cycle of the opposite end, and determining the cycle corresponding to the same cycle number information as the reference cycle of the local end.
The sampling time determining unit 605 is configured to determine the sampling time of the local end in the reference cycle of the local end according to the waveform characteristic of the preset reference sampling time of the opposite end, so as to implement data synchronization between the local end and the opposite end.
In the embodiment of the present invention, the two-terminal current sampling data synchronization process may be performed every n (n is a positive integer) cycles.
It should be appreciated that in other embodiments of the present invention, if the sampling rate is lower than the predetermined threshold, the data synchronization may be performed in conjunction with an interpolation algorithm.
In other embodiments of the present invention, when a line fails, the protection device detects a current break amount, and at this time, data synchronization is suspended, and the protection criterion calculation is performed by delaying the last synchronization result, and data synchronization is recovered when the current break amount disappears.
Further, determining the sampling time of the local terminal in the reference cycle of the local terminal according to the waveform characteristics of the preset reference sampling time of the opposite terminal, including:
and selecting the sampling time corresponding to the waveform with the same waveform characteristics as the preset reference sampling time of the opposite end as the sampling time of the local end from the reference cycle of the local end.
In the embodiment of the invention, the waveform characteristics of the preset reference sampling time of the opposite end are compared in the reference cycle of the local end, and the sampling time corresponding to the waveform with the same waveform characteristics is obtained as the sampling time of the local end, so that the current sampling data of the local end and the current sampling data of the opposite end are synchronized, and reliable protection criteria can be provided for subsequent differential protection.
Further, in the reference cycle of the local terminal, selecting the sampling time corresponding to the waveform with the same waveform characteristics as the preset reference sampling time of the opposite terminal as the sampling time of the local terminal, including:
if the preset reference sampling time of the opposite end is the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive, the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive is selected as the sampling time of the local end in the reference cycle of the local end.
Fig. 5 shows a schematic diagram of selecting sampling instants of a local end according to an embodiment of the present invention. As shown in FIG. 5, if the first cycle 00 of the N terminal is negativeSampling time t corresponding to the first sampling point after positive zero crossing pointN0For presetting the reference sampling time, the reference cycle of the M end can be obtained as the first cycle 00 according to the comparison of the cycle number information, and then the preset reference sampling time t of the N end is usedN0Correspondingly selecting the sampling time t corresponding to the first sampling point after the zero crossing point changed from negative to positive in the first cycle 00 of the M endM0The sampling time of the M end is obtained, so that the current sampling data of the M end and the current sampling data of the N end are synchronized. Similarly, if the sampling time t corresponding to the first sampling point after the negative-to-positive zero crossing point in the second cycle 01 of the N terminalN1For presetting the reference sampling time, the sampling time t corresponding to the first sampling point after the negative-to-positive zero crossing point in the second cycle 01 of the M end can be obtainedM1The sampling time of the M end is obtained, so that the current sampling data of the M end and the current sampling data of the N end are synchronized.
In the above embodiment, the cycle number information where the sampling point is located is added to the current sampling data, and based on the cycle number information and the waveform characteristics corresponding to the cycle number information, synchronous sampling of data at two ends of the distribution network line is realized without depending on a clock signal, and the synchronization performance is not affected in the wireless channel delay jitter range, so that the problem of synchronous sampling of protection data at two ends in distribution network differential protection after a wireless communication technology is adopted is effectively solved, and reliable support is provided for a wireless distribution network protection system.
Further, the apparatus further comprises:
the time calibration unit 600 is configured to calibrate the time information of the local terminal and the time information of the opposite terminal respectively according to the time information obtained from the base station through the wireless communication link before the current sampling is performed on the local terminal and the opposite terminal respectively by using the fixed frequency.
In the embodiment of the invention, the protection devices of the home terminal and the opposite terminal are powered on for the first time, a wireless communication link is established, high-precision time information is obtained from a base station through the wireless communication link, and the time information of the home terminal and the time information of the opposite terminal are respectively calibrated according to the time information, so that the synchronization of initial sampling time is realized.
In the embodiment, the time calibration is completed in advance according to the base station before the current sampling at the two ends, so that the accuracy of the current sampling moment can be improved, and the reliability of the subsequent data synchronization at the two ends is improved.
It should be noted that, during or after the data synchronization at the two ends, if the wireless communication link is abnormal or interrupted and is recovered again, the protection device needs to operate the data synchronization device at the two ends based on wireless communication again, and after the time information at the two ends is recalibrated, the current sampling data synchronization at the two ends is performed again.
The invention also provides a computer readable storage medium, which stores one or more programs, and the programs are used by one or more processors to implement any one of the relay protection data synchronization methods based on wireless communication.
The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.
Claims (11)
1. A relay protection data synchronization method based on wireless communication is characterized by comprising the following steps:
respectively sampling current of the local terminal and the opposite terminal by adopting fixed frequency to obtain current sampling data of the local terminal and current sampling data of the opposite terminal;
the current sampling data of the local terminal is sent to the opposite terminal through a wireless communication link so that the opposite terminal can carry out current sampling according to the current sampling data of the local terminal at the same time, and the current sampling data sent from the opposite terminal through the wireless communication link is received at the local terminal; the current sampling data of the local end and the current sampling data of the opposite end both comprise at least one cycle, the waveform of each cycle comprises a sampling point changing from positive to negative zero crossing point and a sampling point changing from negative to positive zero crossing point, and each data frame of the current sampling data of the local end and the current sampling data of the opposite end comprises cycle serial number information of the sampling point;
respectively extracting cycle sequence number information in the current sampling data of the local terminal and the current sampling data of the opposite terminal and waveform characteristics corresponding to each cycle sequence number information;
taking the cycle at the preset reference sampling time of the opposite end as a reference cycle, and sequentially comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end to determine the reference cycle of the local end;
and selecting the sampling time corresponding to the waveform with the same waveform characteristics as the preset reference sampling time of the opposite end as the sampling time of the local end in the reference cycle of the local end so as to realize the data synchronization of the local end and the opposite end.
2. The method according to claim 1, wherein the determining the reference cycle of the local end by sequentially comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end comprises:
and sequentially judging whether the cycle number information of the local end is the same as the cycle number of the reference cycle of the opposite end according to a preset sequence, and if so, determining the local end cycle with the same cycle number information as the reference cycle of the local end.
3. The method of claim 2, wherein the predetermined order comprises:
and according to the sequence of cycle sequence number information in the buffer area of the local terminal protection device from back to front.
4. The method according to claim 1, wherein selecting, from the reference cycle at the home terminal, a sampling time corresponding to a waveform having a same waveform characteristic as a preset reference sampling time at an opposite terminal as the sampling time at the home terminal comprises:
if the preset reference sampling time of the opposite end is the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive, the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive is selected as the sampling time of the local end in the reference cycle of the local end.
5. The method of any of claims 1-4, wherein prior to sampling the current with the fixed frequency, the method further comprises:
and respectively calibrating the time information of the local terminal and the opposite terminal according to the time information acquired from the base station through the wireless communication link.
6. A relay protection data synchronization device based on wireless communication, the device comprising:
the data sampling unit is used for respectively sampling current of the local terminal and the opposite terminal by adopting fixed frequency so as to obtain current sampling data of the local terminal and current sampling data of the opposite terminal;
the data receiving and sending unit is used for sending the current sampling data of the local terminal to the opposite terminal through the wireless communication link so as to enable the opposite terminal to carry out current sampling according to the current sampling data of the local terminal at the synchronous moment, and receiving the current sampling data sent by the opposite terminal through the wireless communication link at the local terminal; the current sampling data of the local end and the current sampling data of the opposite end both comprise at least one cycle, the waveform of each cycle comprises a sampling point changing from positive to negative zero crossing point and a sampling point changing from negative to positive zero crossing point, and each data frame of the current sampling data of the local end and the current sampling data of the opposite end comprises cycle serial number information of the sampling point;
the data extraction unit is used for respectively extracting cycle number information in the current sampling data of the local terminal and the current sampling data of the opposite terminal and waveform characteristics corresponding to each cycle number information;
the reference cycle determining unit is used for taking the cycle at the preset reference sampling time of the opposite end as a reference cycle, sequentially comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end, and determining the reference cycle of the local end;
and the sampling moment determining unit is used for selecting the sampling moment corresponding to the waveform with the same waveform characteristics as the preset reference sampling moment of the opposite terminal from the reference cycle of the local terminal as the sampling moment of the local terminal so as to realize the data synchronization of the local terminal and the opposite terminal.
7. The apparatus according to claim 6, wherein said comparing the cycle number information of the local end with the cycle number of the reference cycle of the opposite end in sequence to determine the reference cycle of the local end comprises:
and sequentially judging whether the cycle number information of the local end is the same as the cycle number of the reference cycle of the opposite end according to a preset sequence, and if so, determining the local end cycle with the same cycle number information as the reference cycle of the local end.
8. The apparatus of claim 7, wherein the predetermined sequence comprises:
and according to the sequence of cycle sequence number information in the buffer area of the local terminal protection device from back to front.
9. The apparatus according to claim 6, wherein the selecting, from the reference cycle at the local end, the sampling time corresponding to the waveform with the same waveform characteristics as the preset reference sampling time at the opposite end as the sampling time at the local end comprises:
if the preset reference sampling time of the opposite end is the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive, the sampling time corresponding to the first sampling point after the cycle is changed from positive to negative or from negative to positive is selected as the sampling time of the local end in the reference cycle of the local end.
10. The apparatus of any of claims 6-9, further comprising:
and the time calibration unit is used for respectively calibrating the time information of the local terminal and the opposite terminal according to the time information acquired from the base station through the wireless communication link before the current sampling is respectively carried out on the local terminal and the opposite terminal by adopting the fixed frequency.
11. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the method according to any one of claims 1 to 5.
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