Low-voltage transformer area topological structure identification method based on high and low frequency characteristic signals

Abstract

The invention discloses a low-voltage transformer area topological structure identification method based on high and low frequency characteristic signals, and relates to the technical field of power system automation, and the method comprises the steps: sending a preset center frequency, a preset sending moment and a preset topology starting instruction to a sending device and an identification device of a low-voltage transformer area, and starting topology identification; the sending device sends a current signal with a characteristic sequence according to the received center frequency and respective sending time, and the identification device identifies the current signal with the characteristic sequence and uploads an identification result to the terminal; and the terminal sorts recognition results of multiple rounds and gives a final topological structure sorting result. According to the method and the device, the characteristic current signals with different frequencies are sent in different rounds, and comprehensive judgment is carried out in combination with the signal intensity identified by the identification equipment in each round, so that the current branch and the adjacent branch can still be distinguished in the transformer area with abnormal shunting of the adjacent branch, and accurate topology carding is further realized.

Description

Technical Field

[0001] The present application relates to the technical field of power system automation, and in particular to a method for identifying a low-voltage substation topology structure based on high- and low-frequency characteristic signals. Background Art

[0002] With the construction of smart grids and new power systems, lean management of low-voltage substations has become increasingly important. Substation topology is the basis of lean management and is directly related to fault repair, line loss management, and the operation effect after connecting to new energy equipment. Therefore, optimizing the topology of low-voltage substations is crucial to improving the reliability and efficiency of the power system.

[0003] At present, the methods for low-voltage substation topology identification mainly include characteristic current method and big data analysis method. Among them, the characteristic current method has a wider range of application scenarios, especially suitable for substations under certain conditions, such as relatively balanced power load, low data collection success rate, or no power in some substations. This method can achieve a higher substation identification success rate under these special environments.

[0004] However, due to differences in line structure and power load in different substations, the attenuation characteristics of characteristic current signals are also different, which brings certain challenges to accurate identification. In addition, the characteristic current method usually uses a single central frequency point for topological identification, but when there is shunting between adjacent branches, topological identification errors are also prone to occur. Therefore, how to overcome these differences and improve identification accuracy remains a key issue in research and application. Summary of the invention

[0005] To this end, the present application provides a method for identifying the topological structure of a low-voltage substation based on high and low frequency characteristic signals to solve the problem of errors in the low-voltage substation topology identification method in the prior art.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] In a first aspect, a method for identifying a low-voltage area topology structure based on high- and low-frequency characteristic signals is provided, the method being applied to a terminal, comprising:

[0008] Step 1: Send the preset center frequency, transmission time and topology start instruction to the transmission device and identification device of the low voltage area, and start the topology identification; the transmission device sends the current signal with the characteristic sequence according to the received center frequency and the respective transmission time, the identification device identifies the current signal with the characteristic sequence, and uploads the identification result to the terminal; the identification result includes the current signal strength with the characteristic sequence;

[0009] Step 2: receiving the recognition result sent by the recognition device, and determining whether the recognition result satisfies C0=P1j_k>P2j_k>...PNj_k; wherein Pij_k represents the current signal strength with a characteristic sequence, j represents the serial number of the sending device, k represents the serial number of the recognition device, i represents the i-th round, and N represents the total number of rounds;

[0010] Step 3: If the recognition result does not satisfy C0=P1j_k>P2j_k>…PNj_k, then the recognition record of the jth sending device by the kth receiving device is eliminated;

[0011] Step 4: If the identification result satisfies C0=P1j_k>P2j_k>...PNj_k, then sort out the sending devices attached to each receiving device in turn, and record the sending devices attached to the kth receiving device as k0~kn;

[0012] Step 5: Determine whether the sending devices with sending device serial numbers k0 to kn attached to the kth receiving device include the kith receiving device;

[0013] Step 6: If the kith receiving device is included, the kith receiving device is a receiving device under the kth receiving device, and the identification record of the kith receiving device is removed from k0~kn, and the other sending devices are used as direct attachment devices of the kth receiving device;

[0014] Step 7: Traverse all sending devices and receiving devices to finally obtain the overall topological structure of the low-voltage area.

[0015] Preferably, in step 1, the center frequency is 625 Hz, 833.33 Hz or 1666.67 Hz.

[0016] Preferably, in step 1, the sending device is a device with a micro-current sending function in a low-voltage area.

[0017] Preferably, the sending device is an electric energy meter, an LTU or an intelligent circuit breaker.

[0018] Preferably, in step 1, the identification device is a device having a topology identification function in a low-voltage area.

[0019] Preferably, the identification device is an LTU or an intelligent circuit breaker.

[0020] Preferably, in step 1, the characteristic sequence is 0xAAE9, and the signal intensity of the characteristic frequency at the position corresponding to three consecutive 1s having the current signal intensity of the characteristic sequence being E.

[0021] In a second aspect, a low voltage area topology structure identification device based on high and low frequency characteristic signals comprises:

[0022] The data transmission module is used to send the preset center frequency, transmission time and topology start instruction to the transmission device and identification device of the low-voltage area, and start the topology identification; the transmission device sends the current signal with the characteristic sequence according to the received center frequency and the respective transmission time, the identification device identifies the current signal with the characteristic sequence, and uploads the identification result to the terminal; the identification result includes the current signal strength with the characteristic sequence;

[0023] A first judgment module is used to receive the recognition result sent by the recognition device, and judge whether the recognition result satisfies C0=P1j_k>P2j_k>...PNj_k; wherein Pij_k represents the current signal strength with a characteristic sequence, j represents the serial number of the sending device, k represents the serial number of the recognition device, i represents the i-th round, and N represents the total number of rounds;

[0024] A first data elimination module is used to eliminate the identification record of the kth receiving device to the jth sending device if the identification result does not satisfy C0=P1j_k>P2j_k>...PNj_k;

[0025] A data combing module is used to comb through the sending devices connected to each receiving device in turn if the recognition result satisfies C0=P1j_k>P2j_k>...PNj_k, and record the serial numbers of the sending devices connected to the kth receiving device as k0~kn;

[0026] The second judgment module is used to judge whether the sending devices with sending device serial numbers k0 to kn attached to the kth receiving device include the kith receiving device;

[0027] The second data elimination module is used for, if the ki th receiving device is included, the ki th receiving device is a receiving device under the k th receiving device, then the identification record of the ki th receiving device is eliminated from k0-kn, and the other sending devices are directly connected devices of the k th receiving device;

[0028] The traversal module is used to traverse all sending devices and receiving devices, and finally obtain the overall topological structure of the low-voltage area.

[0029] Compared with the prior art, this application has at least the following beneficial effects:

[0030] The present application provides a method for identifying the topological structure of a low-voltage substation based on high and low frequency characteristic signals. The method performs comprehensive judgment by sending characteristic current signals of different frequencies in different rounds and combining the signal strength recognized by the identification device in each round. While realizing signal recognition, the affiliation between the sending device and the identification device is also effectively sorted out, avoiding the ambiguity and misjudgment results caused by the method of sending a single frequency signal when setting the signal threshold. In addition, in the substation where the adjacent branch shunt is abnormal, the current branch and the adjacent branch can still be distinguished, thereby realizing accurate topological structure sorting. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more intuitively illustrate the prior art and the present application, exemplary drawings are given below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing the present application; for example, those skilled in the art are capable of easily making conventional adjustments or further optimizations to the addition / reduction / attribution division, specific shapes, positional relationships, connection methods, dimensional ratios, etc. of certain units (components) based on the technical concepts and exemplary drawings disclosed in the present application.

[0032] Figure 1 A flow chart of a method for identifying a low-voltage area topology structure based on high and low frequency characteristic signals provided in Example 1 of the present application;

[0033] Figure 2 An overall flow chart of a method for identifying a low-voltage area topology structure based on high- and low-frequency characteristic signals provided in Example 1 of the present application;

[0034] Figure 3 The PWM signal waveform diagram when the center frequency provided in the first embodiment of the present application is set to 625 Hz, 833.33 Hz and 1666.67 Hz;

[0035] Figure 4 The current signal waveform diagram when the center frequency provided in Example 1 of the present application is set to 625 Hz, 833.33 Hz and 1666.67 Hz;

[0036] Figure 5 A signal attenuation characteristic diagram in a conventional station area provided in Example 1 of the present application;

[0037] Figure 6 This is a signal splitting characteristic diagram in a conventional station area provided in Example 1 of the present application. DETAILED DESCRIPTION

[0038] The present application is further described below in detail through specific embodiments in conjunction with the accompanying drawings.

[0039] In the description of this application: unless otherwise specified, the meaning of "plurality" is two or more. The terms "first", "second", "third", etc. in this application are intended to distinguish the objects referred to, and do not have special meanings in terms of technical connotations (for example, they should not be understood as emphasizing the importance or order, etc.). Expressions such as "including", "comprising", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

[0040] The terms such as "upper", "lower", "left", "right", "middle", etc. cited in this application are usually used to indicate the general relative position relationship for the purpose of intuitive understanding by referring to the drawings, and are not absolute limitations on the position relationship in the actual product.

[0041] Embodiment 1

[0042] This embodiment provides a method for identifying the topological structure of a low-voltage substation based on high- and low-frequency characteristic signals. In a substation with abnormal adjacent branch diversion, signals of multiple frequencies are sent multiple times, and the signal strength results of multiple frequencies are integrated to distinguish the current branch from the adjacent branches, thereby achieving accurate topology combing.

[0043] See also Figure 1 and Figure 2 This embodiment provides a method for identifying a low-voltage area topology structure based on high- and low-frequency characteristic signals. The method is applied to a terminal and includes:

[0044] S1: Send the preset center frequency, transmission time and topology start command to the transmission device and identification device of the low voltage area, and start the topology identification; the transmission device sends the current signal with the characteristic sequence according to the received center frequency and the respective transmission time, the identification device identifies the current signal with the characteristic sequence, and uploads the identification result to the terminal; the identification result includes the current signal strength with the characteristic sequence;

[0045] Specifically, the total number of topology recognition rounds N and the center frequency Fi of the characteristic signal are pre-set, and the current topology recognition round i is set to 1. The center frequency Fi can be set to 625Hz, 833.33Hz, 1666.67Hz, etc., and the size relationship of the center frequency setting is F1 <F2<…<FN。

[0046] After setting the total rounds N of topology identification and the center frequency Fi of the characteristic signal, the terminal starts the topology identification function: the terminal sends the frequency parameter Fi, the sending time T and the topology start instruction to the sending device and the identification device in the low-voltage area, and starts the identification function itself.

[0047] The sending device sends a current signal with a characteristic sequence (i.e., a characteristic signal) according to the center frequency parameter and its respective sending time. The identification device continuously identifies the current signal. While identifying the characteristic signal, the identification device records the intensity Pij_k of the characteristic signal, where j is the serial number of the sending device, k is the serial number of the identification device, and the identification device reports the identification result to the terminal, and the terminal ends the topology identification function.

[0048] It should be noted that the characteristic sequence is default set to 0xAAE9, and the signal intensity is the signal intensity of the characteristic frequency corresponding to the positions of three consecutive 1s of E.

[0049] In this step, the sending devices are the devices in the power distribution area with the function of sending microcurrents, including electric energy meters, LTUs, intelligent circuit breakers, etc., and the receiving devices are the devices in the power distribution area with the topology identification function, including LTUs, intelligent circuit breakers, terminals, etc.

[0050] In this step, if there is no identification record in the identification device after the sending device sends multiple times, it means that the noise interference at this frequency point is serious in the current power consumption environment, and the frequency point of the characteristic current is replaced accordingly.

[0051] S2: Receive the identification result sent by the identification device, and determine whether the identification result satisfies C0 = P1j_k > P2j_k >... > PNj_k; where Pij_k represents the intensity of the current signal with the characteristic sequence, j represents the serial number of the sending device, k represents the serial number of the identification device, i represents the i-th round, and N represents the total number of rounds.

[0052] Specifically, in this step, it is necessary to first determine whether the topology identification round i is equal to the total number of rounds N. If i < N, then i = i + 1, and S1 is continued to be executed; if i = N, then the affiliation relationship between the k-th receiving device and the j-th sending device is determined according to C0 = P1j_k > P2j_k >... > PNj_k.

[0053] S3: If the identification result does not satisfy C0 = P1j_k > P2j_k >... > PNj_k, then delete the identification record of the k-th receiving device for the j-th sending device.

[0054] Specifically, if the identification result does not satisfy C0 = P1j_k > P2j_k >... > PNj_k, then record C0 = 0. Therefore, when C0 = 0, the identification record of the k-th receiving device for the j-th sending device is deleted.

[0055] S4: If the identification result satisfies C0 = P1j_k > P2j_k >... > PNj_k, then sequentially sort out the sending devices connected to the lower level of each receiving device, and record the serial numbers of the sending devices connected to the lower level of the k-th receiving device as k0 to kn.

[0056] Specifically, if the identification result satisfies C0=P1j_k>P2j_k>...PNj_k, then C0=1. Therefore, if C0=1, the sending devices connected to each receiving device are sorted out in turn, and the sending devices connected to the kth receiving device are numbered k0-kn.

[0057] S5: Determine whether the sending devices with sending device serial numbers k0 to kn attached to the kth receiving device include the kith receiving device;

[0058] S6: If the kith receiving device is included, the kith receiving device is a receiving device under the kth receiving device, and the identification record of the kith receiving device is removed from k0-kn, and the other sending devices are directly connected to the kth receiving device;

[0059] S7: Traverse all sending devices and receiving devices to finally obtain the overall topological structure of the low-voltage area.

[0060] Specifically, all sending devices and receiving devices are traversed, S1 and S6 are executed, and finally the overall topological structure of the low-voltage area can be obtained.

[0061] See also Figure 3 , Figure 3 The PWM signal waveform diagram when the center frequency of this embodiment is set to 625Hz, 833.33Hz, and 1666.67Hz, where the duty cycle of the PWM signal is 1 / 3, and the PWM period is Tpwm=1 / Fpwm. Therefore, the PWM periods corresponding to the above frequencies are 1.6ms, 1.2ms, and 0.6ms, respectively. The changing trends of the PWM period and frequency can be seen from the PWM waveforms of each frequency. The PWM signals of the above three frequencies are used to modulate the 50Hz constant current signal, and the characteristic current signals of the three center frequencies are as follows: Figure 4 As shown, due to the modulation of the 50 Hz constant current signal, the frequency of the characteristic current signal with the center frequency Fi is Fi±50 Hz.

[0062] See also Figure 5 , Figure 5 This is the signal attenuation characteristic diagram of this embodiment in a conventional substation. It can be seen that for the current branch, the higher the frequency, the greater the signal attenuation. Therefore, for the same transmitting device and receiving device, when the power conditions are not much different, the lower the frequency of the characteristic signal, the higher the recognition signal strength of the receiving device, satisfying the judgment condition of P1j_k>P2j_k>…PNj_k.

[0063] See also Figure 6 , Figure 6This is a signal shunting characteristic diagram of this embodiment in a conventional station area. It can be seen that for adjacent branches, the characteristic current frequency is within a certain range. The higher the frequency, the greater the signal shunting. However, there is no uniform attenuation characteristic in the entire effective frequency band.

[0064] The present embodiment provides a method for identifying the topological structure of a low-voltage substation based on high and low frequency characteristic signals. The method sends characteristic current signals of different frequencies in different rounds, and makes a comprehensive judgment based on the signal strength recognized by the recognition device in each round. While realizing signal recognition, the affiliation between the sending device and the recognition device is also effectively sorted out, thereby avoiding ambiguity and misjudgment results caused by the method of sending a single frequency signal when setting the signal threshold. In addition, in the substation where the adjacent branch diversion is abnormal, the current branch and the adjacent branch can still be distinguished, thereby realizing accurate topological structure sorting, which can be applicable to more power usage scenarios.

[0065] Embodiment 2

[0066] This embodiment provides a low-voltage station area topology structure identification device based on high and low frequency characteristic signals, including:

[0067] The data transmission module is used to send the preset center frequency, transmission time and topology start instruction to the transmission device and identification device of the low-voltage area, and start the topology identification; the transmission device sends the current signal with the characteristic sequence according to the received center frequency and the respective transmission time, the identification device identifies the current signal with the characteristic sequence, and uploads the identification result to the terminal; the identification result includes the current signal strength with the characteristic sequence;

[0068] A first judgment module is used to receive the recognition result sent by the recognition device, and judge whether the recognition result satisfies C0=P1j_k>P2j_k>...PNj_k; wherein Pij_k represents the current signal strength with a characteristic sequence, j represents the serial number of the sending device, k represents the serial number of the recognition device, i represents the i-th round, and N represents the total number of rounds;

[0069] A first data elimination module is used to eliminate the identification record of the kth receiving device to the jth sending device if the identification result does not satisfy C0=P1j_k>P2j_k>...PNj_k;

[0070] A data combing module is used to comb through the sending devices connected to each receiving device in turn if the recognition result satisfies C0=P1j_k>P2j_k>...PNj_k, and record the serial numbers of the sending devices connected to the kth receiving device as k0~kn;

[0071] The second judgment module is used to judge whether the sending devices with sending device serial numbers k0 to kn attached to the kth receiving device include the kith receiving device;

[0072] The second data elimination module is used for, if the ki th receiving device is included, the ki th receiving device is a receiving device under the k th receiving device, then the identification record of the ki th receiving device is eliminated from k0-kn, and the other sending devices are directly connected devices of the k th receiving device;

[0073] The traversal module is used to traverse all sending devices and receiving devices, and finally obtain the overall topological structure of the low-voltage area.

[0074] For the specific implementation content of each module in a low-voltage substation topology structure identification device based on high and low frequency characteristic signals, please refer to the above definition of a low-voltage substation topology structure identification method based on high and low frequency characteristic signals, which will not be repeated here.

[0075] The technical features of the above embodiments may be arbitrarily combined (as long as there is no contradiction in the combination of these technical features). To make the description concise, not all possible combinations of the technical features in the above embodiments are described; these embodiments that are not explicitly written should also be considered to be within the scope of this specification.

Claims

1. A method for identifying low-voltage area topology based on high- and low-frequency characteristic signals, characterized in that: The method is applied to a terminal, comprising: Step 1: Send the preset center frequency, transmission time and topology start instruction to the transmission device and identification device of the low voltage area, and start the topology identification; the transmission device sends the current signal with the characteristic sequence according to the received center frequency and the respective transmission time, the identification device identifies the current signal with the characteristic sequence, and uploads the identification result to the terminal; the identification result includes the current signal strength with the characteristic sequence; Step 2: receiving the recognition result sent by the recognition device, and determining whether the recognition result satisfies C0=P1j_k>P2j_k>...PNj_k; wherein Pij_k represents the current signal strength with a characteristic sequence, j represents the serial number of the sending device, k represents the serial number of the recognition device, i represents the i-th round, and N represents the total number of rounds; Step 3: If the recognition result does not satisfy C0=P1j_k>P2j_k>…PNj_k, then the recognition record of the jth sending device by the kth receiving device is eliminated; Step 4: If the identification result satisfies C0=P1j_k>P2j_k>...PNj_k, then sort out the sending devices attached to each receiving device in turn, and record the sending devices attached to the kth receiving device as k0~kn; Step 5: Determine whether the sending devices with sending device serial numbers k0 to kn attached to the kth receiving device include the kith receiving device; Step 6: If the kith receiving device is included, the kith receiving device is a receiving device under the kth receiving device, and the identification record of the kith receiving device is removed from k0~kn, and the other sending devices are used as direct attachment devices of the kth receiving device; Step 7: Traverse all sending devices and receiving devices to finally obtain the overall topological structure of the low-voltage area.

2. The method for identifying the low voltage area topology structure based on high and low frequency characteristic signals according to claim 1 is characterized in that: In step 1, the center frequency is 625 Hz, 833.33 Hz or 1666.67 Hz.

3. The method for identifying the low voltage area topology structure based on high and low frequency characteristic signals according to claim 1 is characterized in that: In step 1, the sending device is a device with a micro-current sending function in a low-voltage area.

4. The method for identifying the low voltage area topology structure based on high and low frequency characteristic signals according to claim 3 is characterized in that: The sending device is an electric energy meter, an LTU or an intelligent circuit breaker.

5. The method for identifying the low voltage area topology structure based on high and low frequency characteristic signals according to claim 1 is characterized in that: In step 1, the identification device is a device with a topology identification function in a low-voltage area.

6. The method for identifying the low voltage area topology structure based on high and low frequency characteristic signals according to claim 5 is characterized in that: The identification device is an LTU or an intelligent circuit breaker.

7. The method for identifying low-voltage area topology based on high- and low-frequency characteristic signals according to claim 1, characterized in that: In step 1, the characteristic sequence is 0xAAE9, and the signal intensity of the characteristic frequency at the position corresponding to three consecutive 1s having the current signal intensity of the characteristic sequence is E.

8. A low voltage station area topology structure identification device based on high and low frequency characteristic signals, characterized in that: include: The data transmission module is used to send the preset center frequency, transmission time and topology start instruction to the transmission device and identification device of the low-voltage area, and start the topology identification; the transmission device sends the current signal with the characteristic sequence according to the received center frequency and the respective transmission time, the identification device identifies the current signal with the characteristic sequence, and uploads the identification result to the terminal; the identification result includes the current signal strength with the characteristic sequence; A first judgment module is used to receive the recognition result sent by the recognition device, and judge whether the recognition result satisfies C0=P1j_k>P2j_k>...PNj_k; wherein Pij_k represents the current signal strength with a characteristic sequence, j represents the serial number of the sending device, k represents the serial number of the recognition device, i represents the i-th round, and N represents the total number of rounds; A first data elimination module is used to eliminate the identification record of the kth receiving device to the jth sending device if the identification result does not satisfy C0=P1j_k>P2j_k>...PNj_k; A data combing module is used to comb through the sending devices connected to each receiving device in turn if the recognition result satisfies C0=P1j_k>P2j_k>...PNj_k, and record the serial numbers of the sending devices connected to the kth receiving device as k0~kn; The second judgment module is used to judge whether the sending devices with sending device serial numbers k0 to kn attached to the kth receiving device include the kith receiving device; The second data elimination module is used for, if the ki th receiving device is included, the ki th receiving device is a receiving device under the k th receiving device, then the identification record of the ki th receiving device is eliminated from k0-kn, and the other sending devices are directly connected devices of the k th receiving device; The traversal module is used to traverse all sending devices and receiving devices, and finally obtain the overall topological structure of the low-voltage area.

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