Deterministic network data packet sending method and device of substation automation system

Abstract

The invention discloses a deterministic network data packet sending method of a power transformation automation system. The method comprises the following steps: judging whether a data packet can arrive at required time or not by adopting a path algorithm; if the required time is reached, single-channel transmission is carried out; and if the required time cannot be reached, the data packet is sliced by adopting a slicing algorithm, and then the sliced data packet is simultaneously sent in multiple channels by adopting a wavelength division multiplexing technology. According to the method, after the big data packet is sliced, different slices are simultaneously sent by different wavelengths, so that the problems that the big data packet needs to be queued to be sent after being sliced and the arrival time is relatively long can be solved, the big data transmission time can be reduced, and the problem of cooperative work of multiple on-line units at determined time can be solved. The method is especially suitable for coordination control and time synchronization of a plurality of intelligent substations in electric power automation.

Description

Technical Field

[0001] The invention belongs to the field of deterministic networks of substation automation systems. Background Art

[0002] With the construction of energy Internet, automation business applications are developing rapidly, and the demand for strong real-time, large-capacity, and integrated data transmission is becoming more and more urgent. The performance of traditional "best effort" Ethernet can no longer meet the requirements. Research on key technologies of deterministic networks in substation automation systems can achieve efficient operation of substation automation systems. In traditional networks, large data packets are sent in sequence after data packet slicing. This method cannot meet the needs of power automation, such as time synchronization data and control data delays, which are required to be less than 3ms. Summary of the invention

[0003] Based on this, the present invention proposes a deterministic network data packet sending method for a substation automation system, which is used to solve the problem of large data packets that are sensitive to delays, so that they can quickly arrive at a certain location at a certain time.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: a deterministic network data packet sending method of a substation automation system, comprising:

[0005] Use path algorithms to determine whether data packets can arrive at the required time;

[0006] If it can arrive at the required time, it will be sent through a single channel;

[0007] If the data packet cannot arrive at the required time, a slicing algorithm is used to slice the data packet, and then wavelength division multiplexing technology is used to send the sliced ​​data packets simultaneously in multiple channels.

[0008] The path algorithm is specifically:

[0009] On a certain network topology, a transmission path of a group of data packets P is given, where the period, sending time and path of each data packet P are recorded as P.Per, Lenp and Listp respectively; a six-tuple of data packet P is defined (Src, Des, Pir, Per, Tst, Tde), where P.Src is defined as the source node of data packet P, P.Des is the destination node of data packet P, P.Pir is the priority of data packet P, P.Per is the frame period of data packet P, P.Tst is the relative time when data packet P is generated, P.Tde is the deadline for completion of data packet P, Lenp is the length of time occupied by the transmission of data packet P, Listp is the transmission path of data packet P, that is, data packet P is a list of nodes passed in sequence, Hf is a super period of a group of data packets P, and Sf is the number of frames sent by data packet P in the super period. For each data packet P, solve the sending time and deadline of each data packet, where ω represents the sending time of the data packet, η represents the deadline of the data packet, ε represents the transmission time of the data packet, u represents the size of the data packet, and v represents the transmission speed. For the wth data packet, we have:

[0010] ω=P.Tst+(W-1)×P.Per

[0011] η=(w-1)×P.Per+P.Tde

[0012]

[0013] If ε≤η-ω, the data packet can arrive at the required time;

[0014] If ε>η-ω, then the data packet cannot arrive at the required time.

[0015] The slicing algorithm is specifically:

[0016] (1) Divide data packet P into 2+i data packets P1 and P2 equally, where i=0 at the beginning; calculate the time required for sending data packets P1 and P2 simultaneously using the path algorithm to see whether it satisfies ε≤η-ω. If so, use two channels to send data packets P1 and P2 simultaneously;

[0017] (2) If ε≤η-ω is not satisfied, then after i is increased by 1, the data packet is evenly sliced ​​into data packets P1---P 2+ i. Calculate the data packet P1---P according to the algorithm of the above path 2+ Does the time required for simultaneous transmission of i satisfy ε≤η-ω? If so, use (2+i) channels to simultaneously send the sliced ​​data packets P1---P 2+ i;

[0018] (3) If i is increased by 1, the packet will be evenly divided into data packets P1---P 2+ i, calculate the data packet P1---P according to the above path algorithm 2+ If the time required for simultaneous transmission of i does not satisfy ε≤η-ω, then i is increased by 1, the data packets are evenly divided again, and the above steps are repeated until the time required for simultaneous transmission satisfies ε≤η-ω.

[0019] The use of wavelength division multiplexing technology to send the sliced ​​data packets through multiple channels simultaneously is specifically: using wavelength division multiplexing channels to send the sliced ​​data packets;

[0020] The wavelength division multiplexing channel includes a wide spectrum light source, a tunable filter for wavelength division, an optical modulator for modulating the sliced ​​data into optical information, and a combiner for coupling different wavelengths into one channel;

[0021] According to the wavelength range Δλ of the wide-spectrum light source, adjust the wavelength of the tunable filter so that the output light wave is consistent with the data packet P1---P 2+i One-to-one correspondence λ1---λ 2+i , whose wavelength interval is Δλ / (2+i-1);

[0022] The data packet P1---P 2+i Encoding is performed to facilitate restoration into a large data packet. Four hexadecimal data are added to the front of the frame header. The first bit indicates the wavelength band of the wavelength channel, the second bit indicates the position of the data packet before data packet slicing, the third bit indicates the central wavelength of the data packet transmission, and the fourth bit indicates the wavelength interval of the current wavelength division multiplexing channel.

[0023] The present invention also provides a deterministic network data packet sending device for a substation automation system, comprising:

[0024] Arbitration module, used to determine whether the data packet can arrive at the required time;

[0025] A single-channel sending module is used to send data packets that can arrive at the required time;

[0026] The multi-channel sending module is used to slice the data packets that cannot arrive at the required time using a slicing algorithm, and then use wavelength division multiplexing technology to simultaneously send the sliced ​​data packets.

[0027] The multi-channel sending module includes a wavelength division multiplexing channel for sending sliced ​​data packets; the wavelength division multiplexing channel includes a wide-spectrum light source, a tunable filter for wavelength division, an optical modulator for modulating the sliced ​​data into optical information, and a combiner for coupling different wavelengths into one channel.

[0028] The wavelength division multiplexing channel also includes a wavelength scanner, a photoelectric detector, and a shaping amplifier circuit for wavelength division.

[0029] The tunable filter comprises a grating, electrodes are added on both sides of the grating body, and the grating constant is changed by adjusting the voltage applied to the electrodes, thereby adjusting the wavelength emitted by the tunable filter.

[0030] The tunable filter comprises a composite grating, which comprises two layers of gratings, and the two layers of gratings are composed of a fixed grating 1 and a movable grating 2. The slit width of the composite grating is adjusted by moving the movable grating 2, thereby adjusting the wavelength emitted by the tunable filter.

[0031] The movable grating 2 is connected to a high-precision stepping machine for driving the movable grating 2 to move.

[0032] The slit width and grating constant of the fixed grating 1 and the movable grating 2 are the same; the surface where the fixed grating notches are located is arranged opposite to the surface where the movable grating notches are located.

[0033] Compared with the prior art, the invention has the following beneficial effects: the method provided by the invention can solve the problem that large data packets need to be queued and sent after slicing, and the arrival time is long, especially the coordinated control and time synchronization of multiple smart substations in power automation. The method provided by the invention can reduce the time of large data transmission by slicing large data packets and sending different slices at different wavelengths at the same time, and can solve the problem of multiple machines working together at a certain time. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0035] Figure 1 It is a schematic diagram of the sending device of the present invention.

[0036] Figure 2 This is a schematic diagram of a multi-channel sending module.

[0037] Figure 3 This is a schematic diagram of the sending device of Example 1.

[0038] Figure 4 This is a schematic diagram of a multi-channel sending module of Example 1.

[0039] Figure 5 Schematic diagram of the tunable filter of Example 1.

[0040] Figure 6 Schematic diagram of the grating of Example 2. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The first aspect of the present invention provides a deterministic network data packet sending method for a substation automation system, first determining whether a data packet is a large data packet that is sensitive to delay, and if it is a large data packet that is sensitive to delay, slicing the data packet into small data packets, and then sending them using wavelength division multiplexing technology. In this sending method, data packet slicing does not require queuing, and can solve the problem of long sending time for large data packets.

[0043] The present invention also provides a deterministic network data packet sending device for a substation automation system, comprising:

[0044] Arbitration module, used to determine whether the data packet can arrive at the required time;

[0045] A single-channel sending module is used to send data packets that can arrive at the required time;

[0046] The multi-channel sending module is used to slice the data packets that cannot arrive at the required time using a slicing algorithm, and then use wavelength division multiplexing technology to simultaneously send the sliced ​​data packets.

[0047] The multi-channel sending module includes a wavelength division multiplexing channel for sending sliced ​​data packets; the wavelength division multiplexing channel includes a wide-spectrum light source, a tunable filter for wavelength division, an optical modulator for modulating the sliced ​​data into optical information, a combiner for coupling different wavelengths to one channel, a wavelength scanner for wavelength division, a photodetector, and a shaping amplifier circuit.

[0048] like Figure 1 As shown, before a data packet is sent, the arbitration module determines whether the data packet can arrive at the required time. If yes, it is sent through a single channel. If not, the data packet is sliced ​​and sent simultaneously through multiple channels.

[0049] Its algorithm is as follows Figure 2As shown, on a certain network topology, a group of data packets P are given a transmission path, where the period, sending time and path of each data packet P are recorded as P.Per, Lenp and Listp respectively. Define the six-tuple of data packet P (Src, Des, Pir, Per, Tst, Tde), where P.Src is defined as the source node of data packet P, P.Des is the destination node of data packet P, P.Pir is the priority of data packet P, P.Per is the frame period of data packet P, P.Tst is the relative time of data packet P generation, P.tde is the deadline for data packet P to be completed, Lenp is the length of time occupied by data packet P during transmission, Listp is the transmission path of data packet P, that is, data packet P is a list of nodes passed in sequence, Hf is a super period of a group of data packets P, and Sf is the number of frames sent by data packet P in the super period. For each data packet P, solve the sending time and deadline of each data packet, where ω represents the sending time of the data packet, η represents the deadline of the data packet, ε represents the transmission time of the data packet, and u is the size of the data packet. For the wth data packet, we have:

[0050] ω=P.Tst+(w-1)×P.Per

[0051] η=(w-1)×P.Per+P.Tde

[0052]

[0053] ε≤η-ω

[0054] If ε≤η-ω, the data packet is sent through a single channel. If ε>η-ω, the data packet is sliced ​​and sent through multiple channels.

[0055] The slicing algorithm is:

[0056] (1) Divide the data packet P into (2+i) data packets P1 and P2 (i=0 at the beginning). According to the algorithm of the above path, calculate whether the time required for the simultaneous transmission of data packets P1 and P2 satisfies ε≤η-ω. If so, use two channels to send data packets P1 and P2 simultaneously. According to the wavelength range Δλ of the wide-spectrum light source, adjust the modulation voltage applied to the tunable filter, thereby adjusting the grating constant of the filter so that the output light waves are λ1 and λ2, and their wavelength interval is Δλ. Encode data packets P1 and P2, and add 4 hexadecimal data at the front of their frame headers. The first bit indicates the wavelength band of the wavelength channel, the second bit indicates the position of the data packet before the data packet is sliced, the third bit indicates the central wavelength of the data wave transmission, and the fourth bit indicates the wavelength interval of the current wavelength division multiplexing channel.

[0057] (2) If ε≤η-ω is not satisfied, then after i is increased by 1, the data packet is evenly sliced ​​into data packets P1---P2+i . According to the algorithm of the above path, the data packet P1---P 2+i Does the time required for simultaneous transmission satisfy ε≤η-ω? If so, use (2+i) channels to simultaneously send the sliced ​​data packets P1---P 2+i According to the wavelength range Δλ of the wide-spectrum light source, the modulation voltage applied to the tunable filter is adjusted, thereby adjusting the grating constant of the filter and adjusting the emitted wavelength so that the output light wave is λ1---λ 2+i , whose wavelength interval is Δλ / (2+i-1). 2+i Encoding is performed by adding 4 hexadecimal data to the front of the frame header. The first bit indicates the wavelength channel band, the second bit indicates the position of the data packet before data packet slicing, the third bit indicates the central wavelength of the data packet transmission, and the fourth bit indicates the wavelength interval of the current wavelength division multiplexing channel.

[0058] (3) If i is increased by 1, the packet will be evenly divided into data packets P1---P 2+i , according to the algorithm of the above path, the data packet P1---P 2+i If the time required for sending does not satisfy ε≤η-ω, then i is increased by 1, the data packets are evenly divided again, and the above steps are repeated, and so on.

[0059] The fast wavelength division multiplexing channel of the present invention is as follows Figure 2 As shown, it includes a wide-spectrum light source, a tunable filter for wave separation, an optical modulator for modulating the sliced ​​data into optical information, a combiner for coupling different wavelengths into one channel, a wavelength scanner for wave separation, a photodetector, and a shaping amplifier circuit.

[0060] Example 1

[0061] See also Figure 3 , Figure 4 , when a large data packet 100 enters the network, the arbitration module 200 judges that if the data packet can arrive at the required time, it is sent by the single-channel sending module 400. If it is a time-sensitive large data packet 102, it is sent by the multi-channel sending module 300. First, the algorithm calculates how many data slices to be cut into and how many channels to use for sending. After the sliced ​​data packets enter the channel, according to the algorithm allocation, the sliced ​​data packet 102-1 corresponds to the wavelength λ1 to be sent, the sliced ​​data packet 102-2 corresponds to the wavelength λ2 to be sent, and the sliced ​​data packet 102-n corresponds to the wavelength λn to be sent. The light waves carrying the signal are combined by the wavelength coupler 304, transmitted through the optical fiber channel, and demultiplexed by the wavelength scanner 305, and divided into optical signals with wavelengths of λ1, λ2----λn. After the photoelectric detector 306 and the shaping amplifier circuit 307, they are restored to data packet slices, and then restored to large data packets in sequence.

[0062] The tunable filter used in Example 1 includes a grating, such as Figure 5 As shown in 302, a layer of opaque piezoelectric sensitive material is covered on a transparent glass substrate to make the main body of the grating, and electrodes are added on both sides of the main body. Then, using photolithography technology, a grating with a grating constant of the wavelength corresponding to this patent is engraved. By adjusting the voltage applied to the electrode, the grating constant can be changed, thereby adjusting the emitted wavelength. The high-precision CNC stepper 302-4 is used to adjust the position of the extracted light. This tunable filter structure is a prior art and will not be described in detail here.

[0063] Example 2

[0064] The same as in Example 1, except that the tunable filter used is different. The tunable filter used in Example 2 includes a composite grating. Figure 6 As shown, the composite grating includes two layers of gratings, and the two layers of gratings are a fixed grating 1 (320-1) and a movable grating 2 (320-2). The slit width and grating constant of the fixed grating and the movable grating are the same. The surface where the notches of the fixed grating 1 are located is arranged opposite to the surface where the notches of the movable grating 2 are located. The movable grating 2 (320-2) is connected to a high-precision stepper (320-3) for driving the movable grating 2 (320-2) to move. The CPU is connected to the high-precision stepper (320-3). By moving the movable grating 2 (320-2), the slit width of the composite grating is adjusted, thereby adjusting the wavelength emitted by the tunable filter.

[0065] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0066] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1A device that provides the functions specified in a block or multiple blocks.

[0067] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0068] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A deterministic network data packet sending method for a substation automation system, characterized in that: include: Use path algorithms to determine whether data packets can arrive at the required time; If it can arrive at the required time, it will be sent through a single channel; If the data packet cannot arrive at the required time, a slicing algorithm is used to slice the data packet, and then wavelength division multiplexing technology is used to send the sliced ​​data packets simultaneously in multiple channels.

2. The deterministic network data packet sending method of the substation automation system according to claim 1, characterized in that: The path algorithm is specifically: On a certain network topology, given a set of data packets P transmission paths, the period, sending time and path of each data packet P are recorded as P.Per, Lenp and Listp respectively; Define a six-tuple of data packet P (Src, Des, Pir, Per, Tst, Tde), where P.Src is defined as the source node of data packet P, P.Des is the destination node of data packet P, P.Pir is the priority of data packet P, P.Per is the frame period of data packet P, P.Tst is the relative time of data packet P generation, P.Tde is the deadline for data packet P completion, Lenp is the length of time occupied by data packet P transmission, Listp is the transmission path of data packet P, that is, the list of nodes that data packet P passes through in sequence, Hf is a set of super periods of data packet P, and Sf is the number of frames sent by data packet P in the super period. For each data packet P, solve the sending time and deadline of each data packet, where ω represents the sending time of the data packet, η represents the deadline of the data packet, ε represents the transmission time of the data packet, u is the size of the data packet, and v represents the transmission speed. For the wth data packet, we have: ω=P.Tst+(w-1)×P.Per η=(w-1)×P.Per+P.Tde If ε≤η-ω, the data packet can arrive at the required time; If ε>η-ω, then the data packet cannot arrive at the required time.

3. The deterministic network data packet sending method of the substation automation system according to claim 1, characterized in that: The slicing algorithm is specifically: (1) Divide data packet P into 2+i data packets P1 and P2 equally, where i=0 at the beginning; calculate the time required for sending data packets P1 and P2 simultaneously using the path algorithm to see whether it satisfies ε≤η-ω. If so, use two channels to send data packets P1 and P2 simultaneously; (2) If ε≤η-ω is not satisfied, then after i is increased by 1, the data packet is evenly sliced ​​into data packets P1---P 2+i . According to the algorithm of the above path, the data packet P1---P 2+i Does the time required for simultaneous transmission satisfy ε≤η-ω? If so, use (2+i) channels to simultaneously send the sliced ​​data packets P1---P 2+i ; (3) If i is increased by 1, the packet will be evenly divided into data packets P1---P 2+i , according to the above path algorithm, the data packet P1---P 2+i If the time required for simultaneous sending does not satisfy ε≤η-ω, then i is increased by 1, the data packets are evenly divided again, and the above steps are repeated until the time required for simultaneous sending satisfies ε≤η-ω.

4. The deterministic network data packet sending method of the substation automation system according to claim 1, characterized in that: The use of wavelength division multiplexing technology to send the sliced ​​data packets through multiple channels simultaneously is specifically: using wavelength division multiplexing channels to send the sliced ​​data packets; The wavelength division multiplexing channel includes a wide spectrum light source, a tunable filter for wavelength division, an optical modulator for modulating the sliced ​​data into optical information, and a combiner for coupling different wavelengths into one channel; According to the wavelength range Δλ of the wide-spectrum light source, adjust the wavelength of the tunable filter so that the output light wave is consistent with the data packet P1---P 2+i One-to-one correspondence λ1---λ 2+i , whose wavelength interval is Δλ / (2+i-1); The data packet P1---P 2+i Encoding is performed to facilitate restoration into a large data packet. Four hexadecimal data are added to the front of the frame header. The first bit indicates the wavelength band of the wavelength channel, the second bit indicates the position of the data packet before data packet slicing, the third bit indicates the central wavelength of the data packet transmission, and the fourth bit indicates the wavelength interval of the current wavelength division multiplexing channel.

5. A deterministic network data packet sending device for a substation automation system, characterized in that: include: Arbitration module, used to determine whether the data packet can arrive at the required time; A single-channel sending module is used to send data packets that can arrive at the required time; The multi-channel sending module is used to slice the data packets that cannot arrive at the required time using a slicing algorithm, and then use wavelength division multiplexing technology to simultaneously send the sliced ​​data packets.

6. The deterministic network data packet sending device of the substation automation system according to claim 5, characterized in that: The multi-channel sending module includes a wavelength division multiplexing channel for sending sliced ​​data packets; the wavelength division multiplexing channel includes a wide-spectrum light source, a tunable filter for wavelength division, an optical modulator for modulating the sliced ​​data into optical information, and a combiner for coupling different wavelengths into one channel.

7. The deterministic network data packet sending device of the substation automation system according to claim 6, characterized in that: The tunable filter comprises a grating, electrodes are added on both sides of the grating body, and the grating constant is changed by adjusting the voltage applied to the electrodes, thereby adjusting the wavelength emitted by the tunable filter.

8. The deterministic network data packet sending device of the substation automation system according to claim 6, characterized in that: The tunable filter comprises a composite grating, which comprises two layers of gratings, and the two layers of gratings are composed of a fixed grating 1 (320-1) and a movable grating 2 (320-2); the slit width of the composite grating is adjusted by moving the movable grating 2 (320-2), thereby adjusting the wavelength emitted by the tunable filter.

9. The deterministic network data packet sending device of the substation automation system according to claim 8, characterized in that: The movable grating 2 (320-2) is connected to a high-precision stepper (320-3) for driving the movable grating 2 (320-2) to move.

10. The deterministic network data packet sending device of the substation automation system according to claim 8, characterized in that: The slit width and grating constant of the fixed grating 1 (320-1) and the movable grating 2 (320-2) are the same; the surface where the fixed grating notches are located is arranged opposite to the surface where the movable grating notches are located.

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