Converter station AC filter bank commissioning state identification method and system

Abstract

The invention discloses a converter station AC filter bank operation state identification method and system. The method comprises the following steps: synchronously acquiring a converter station AC bus fundamental wave voltage root-mean-square value, an attention frequency harmonic voltage root-mean-square value, an AC filter bank fundamental wave current root-mean-square value and an attention frequency harmonic current root-mean-square value; calculating fundamental wave impedance, attention frequency harmonic impedance and fundamental wave reactive power of the alternating current filter bank in an actual commissioning state; calculating fundamental wave impedance, attention frequency harmonic impedance and fundamental wave reactive power of the alternating current filter bank in the preset commissioning state; comparing the fundamental wave reactive power, the fundamental wave impedance and the concerned frequency harmonic impedance in the actual commissioning state and the preset commissioning state, and judging the actual commissioning state of the AC filter bank; the method has the advantages that the commissioning state of the alternating-current filter bank of the converter station is accurately identified, so that the cause of the abnormal harmonic level of the converter station is determined.

Description

Technical Field

[0001] The present invention relates to the field of converter station operation, and in particular to a method and system for identifying the operation status of an AC filter group of a converter station. Background Art

[0002] In a high-voltage DC converter station, a certain number of filter groups need to be configured on the AC side to filter out a large amount of harmonics generated during the operation of the converter and compensate for the reactive power consumed by the DC control system. The converter that realizes AC / DC conversion absorbs a large amount of reactive power during operation, and the reactive power demand is in a dynamic change process with the operating state of the converter. To ensure the stable operation of the system, the converter station needs to be equipped with different types and numbers of AC filters, and the operation state of the AC filter group needs to be changed in an automatic switching manner to fully compensate for the reactive power absorbed by the converter. In this process, different combinations of AC filters may amplify non-characteristic subharmonics to different degrees. In order to reveal the mechanism of non-characteristic subharmonic amplification caused by AC filter groups and quantify the impact of different types and numbers of AC filter combinations on non-characteristic subharmonic amplification, it is necessary to accurately analyze the operation state of the AC filter group in the converter station.

[0003] However, there is a lack of detailed records of the combination and number of AC filter groups in the converter station, making it difficult to accurately obtain relevant information, resulting in the inability to grasp the operation status of the AC filter group when the harmonic level of the converter station is abnormal, and the inability to establish a corresponding relationship between the two. For example, Chinese Patent Publication No. CN118841981A discloses a coordinated control method for switching AC filter groups suitable for CLCC converter stations and a CLCC converter, which mainly controls the switching of AC filter groups and cannot identify the operation status of AC filter groups when the harmonic level of the converter station is abnormal. Therefore, how to make full use of monitoring data to accurately identify the operation status of the AC filter group in the converter station to clarify the cause of the abnormal harmonic level of the converter station is a key technical problem that needs to be solved urgently. Summary of the invention

[0004] The technical problem to be solved by the present invention is how to accurately identify the operation status of the AC filter group of the converter station so as to clarify the cause of the abnormal harmonic level of the converter station.

[0005] The present invention solves the above technical problems through the following technical means: a method for identifying the operation status of an AC filter group in a converter station, comprising: S1. Synchronously collect the RMS value of the fundamental voltage of the AC busbar of the converter station, the RMS value of the harmonic voltage of the concerned frequency, the RMS value of the fundamental current of the AC filter group, and the RMS value of the harmonic current of the concerned frequency; S2, based on S1, calculates the fundamental impedance, harmonic impedance of the concerned frequency and fundamental reactive power of the AC filter group under the actual operation state; S3, collecting the circuit topology and component parameters of the AC filter, and calculating the fundamental impedance and harmonic impedance of the concerned frequency of the AC filter group under the preset operation state; S4. Calculate the fundamental reactive power of the AC filter group in the preset operation state according to the RMS value of the fundamental voltage of the AC busbar of the converter station and the fundamental impedance of the AC filter group in the preset operation state; S5. Compare the fundamental reactive power, fundamental impedance, and harmonic impedance of the frequency of interest under the actual operation state and the preset operation state to determine whether the preset operation state of the AC filter group is consistent with the actual operation state. If not, reset the operation state and return to execute S3 to S5 until the actual operation state is consistent with the preset operation state. Then, the actual operation state of the AC filter is obtained, thereby realizing the identification of the operation state of the AC filter group.

[0006] Furthermore, S1 includes:

[0007]

[0008]

[0009]

[0010] In the formula, The first A voltage time-domain discrete signal, For the AC filter group A current discrete signal in time domain, is the RMS value of the AC bus fundamental voltage of the converter station; AC busbar for converter station Subharmonic voltage RMS value; For the The RMS value of the fundamental current of the AC filter group; For the AC filter group Subharmonic current RMS value; The number of sampling points of 10 cycles of the discrete time domain signal of the voltage or current waveform; is the number of the discrete signal in the time domain, and its value range is ; is the number of AC filter groups; is the harmonic order; is an imaginary unit; is a natural constant; Indicates the modulus value of the phase quantity.

[0011] Furthermore, S2 includes: The RMS value of the AC bus fundamental voltage of the converter station is The ratio of the fundamental current root mean square value of the AC filter group is taken as the first AC filter group fundamental impedance; AC busbar of converter station The RMS value of the subharmonic voltage is AC filter group The ratio of the root mean square value of the sub-harmonic current is taken as the first AC filter group harmonic impedance; three times the RMS value of the fundamental voltage of the AC busbar of the converter station and the The product of the root mean square value of the fundamental current of the AC filter group is taken as the first Fundamental reactive power of the AC filter group.

[0012] Furthermore, S3 includes: Collect the converter station AC filter circuit topology and component parameters, preset the operation status of the AC filter group, then

[0013]

[0014] In the formula, The first Fundamental impedance of the AC filter group; The first AC filter group Subharmonic impedance; For the Fundamental impedance of the AC filter type; For the AC filter types Subharmonic impedance; For the AC filter group The total number of AC filter types that are expected to be put into operation; is the number of the AC filter type, is the total number of AC filter types.

[0015] Furthermore, S4 includes: The square of the three times the RMS value of the AC bus fundamental voltage of the converter station is equal to the The ratio of the fundamental impedance of the AC filter group is used as the first Fundamental reactive power of AC filter group.

[0016] Furthermore, S5 includes: The preset commissioning state and the actual commissioning state The absolute value of the difference between the fundamental reactive power of the AC filter group and the actual operation state The fundamental reactive power ratio of the AC filter group is used as the fundamental reactive power difference change rate. ; The first The difference between the fundamental impedance of the AC filter group and the actual operation state The ratio of the fundamental impedance of the AC filter group is taken as the The change rate of the fundamental impedance difference of the AC filter group ; The first AC filter group The difference between the subharmonic impedance and the actual operation state AC filter group The ratio of subharmonic impedance is taken as the AC filter group Subharmonic impedance difference change rate ; like and and , then The actual operation status of the AC filter group is consistent with the preset operation status; if or or , then The actual operation status of the group AC filter is inconsistent with the preset operation status, among which, The threshold value of the difference change rate is set.

[0017] The present invention also provides a converter station AC filter group operation status identification system, comprising: A data acquisition module is used to synchronously collect the RMS value of the fundamental voltage of the AC busbar of the converter station, the RMS value of the harmonic voltage of the concerned frequency, the RMS value of the fundamental current of the AC filter group, and the RMS value of the harmonic current of the concerned frequency; The actual operation data calculation module is used to calculate the fundamental impedance, harmonic impedance of the concerned frequency and fundamental reactive power of the AC filter group under the actual operation state based on the data acquisition module; The first preset operation calculation module is used to collect the circuit topology and component parameters of the AC filter, and calculate the fundamental impedance and the harmonic impedance of the concerned frequency of the AC filter group under the preset operation state; The second preset operation calculation module is used to calculate the fundamental reactive power of the AC filter group in the preset operation state according to the RMS value of the fundamental voltage of the AC busbar of the converter station and the fundamental impedance of the AC filter group in the preset operation state; The state identification module is used to compare the fundamental reactive power, fundamental impedance, and harmonic impedance of the frequency of interest under the actual operation state and the preset operation state, and determine whether the preset operation state of the AC filter group is consistent with the actual operation state. If not, the operation state is reset, and the first preset operation calculation module is returned to the state identification module until the actual operation state is consistent with the preset operation state. The actual operation state of the AC filter is obtained, thereby realizing the operation state identification of the AC filter group.

[0018] Furthermore, the data acquisition module is also used for:

[0019]

[0020]

[0021]

[0022] In the formula, The first A voltage time-domain discrete signal, For the AC filter group A current discrete signal in time domain, is the RMS value of the AC bus fundamental voltage of the converter station; AC busbar for converter station Subharmonic voltage RMS value; For the The RMS value of the fundamental current of the AC filter group; For the AC filter group Subharmonic current RMS value; The number of sampling points of 10 cycles of the discrete time domain signal of the voltage or current waveform; is the number of the discrete signal in the time domain, and its value range is ; is the number of AC filter groups; is the harmonic order; is an imaginary unit; is a natural constant; Indicates the modulus value of the phase quantity.

[0023] Furthermore, the actual operation data calculation module is also used for: The RMS value of the AC bus fundamental voltage of the converter station is The ratio of the fundamental current root mean square value of the AC filter group is taken as the first AC filter group fundamental impedance; AC busbar of converter station The RMS value of the subharmonic voltage is AC filter group The ratio of the root mean square value of the sub-harmonic current is taken as the first AC filter group harmonic impedance; three times the RMS value of the fundamental voltage of the AC busbar of the converter station and the The product of the root mean square value of the fundamental current of the AC filter group is taken as the first Fundamental reactive power of the AC filter group.

[0024] Furthermore, the first preset operation calculation module is also used for: Collect the converter station AC filter circuit topology and component parameters, preset the operation status of the AC filter group, then

[0025]

[0026] In the formula, The first Fundamental impedance of the AC filter group; The first AC filter group Subharmonic impedance; For the Fundamental impedance of the AC filter type; For the AC filter types Subharmonic impedance; For the AC filter group The total number of AC filter types that are expected to be put into operation; is the number of the AC filter type, is the total number of AC filter types.

[0027] Furthermore, the second preset operation calculation module is also used for: The square of the three times the RMS value of the AC bus fundamental voltage of the converter station is equal to the The ratio of the fundamental impedance of the AC filter group is used as the first Fundamental reactive power of AC filter group.

[0028] Furthermore, the state identification module is also used for: The preset commissioning state and the actual commissioning state The absolute value of the difference between the fundamental reactive power of the AC filter group and the actual operation state The fundamental reactive power ratio of the AC filter group is used as the fundamental reactive power difference change rate. ; The first The difference between the fundamental impedance of the AC filter group and the actual operation state The ratio of the fundamental impedance of the AC filter group is taken as the The change rate of the fundamental impedance difference of the AC filter group ; The first AC filter group The difference between the subharmonic impedance and the actual operation state AC filter group The ratio of subharmonic impedance is taken as the AC filter group Subharmonic impedance difference change rate ; like and and , then The actual operation status of the AC filter group is consistent with the preset operation status; if or or , then The actual operation status of the group AC filter is inconsistent with the preset operation status, among which, The threshold value of the difference change rate is set.

[0029] The advantages of the present invention are: (1) On the one hand, the present invention uses the voltage and current data of the AC filter group monitored in real time at the converter station to obtain the fundamental impedance, harmonic impedance of the frequency of interest and fundamental reactive power of the AC filter group under the actual operation state; on the other hand, according to the topology and component parameters of all types of AC filters in the converter station, the fundamental impedance and harmonic impedance of the frequency of interest of the AC filter group under the preset operation state are calculated, and according to the root mean square value of the fundamental voltage of the AC bus of the converter station and the fundamental impedance of the AC filter group under the preset operation state, the fundamental reactive power of the AC filter group under the preset operation state is calculated. Finally, based on the difference change rate between the actual operation state and the preset operation state, the operation combination of the AC filter group is identified to achieve accurate identification of the operation state of the AC filter group of the converter station. When the actual operation state of the AC filter is inconsistent with the preset operation state, it means that the preset operation state of the AC filter does not conform to the actual operation state, and it is necessary to reset the operation state, and repeat steps S3, S4, and S5 until the actual operation state is consistent with the preset operation state, so as to clarify the actual operation state of the AC filter group of the converter station. After identifying the actual operation state, it is beneficial to analyze the causes of abnormal harmonic levels in the converter station in the subsequent process.

[0030] (2) In the absence of detailed records of the operation combination and number of AC filter groups in the converter station and in the case where it is difficult to obtain accurate information, this method makes full use of monitoring data to accurately identify the operation status of the AC filter in the converter station. This provides reliable support for revealing the mechanism of non-characteristic subharmonic amplification caused by the AC filter group, quantifying the impact of different types and numbers of AC filter combinations on non-characteristic subharmonic amplification, and clarifying the causes of abnormal harmonic conditions in the converter station. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flowchart of a method for identifying the operation status of an AC filter group in a converter station disclosed in an embodiment of the present invention; Figure 2 A schematic diagram of the locations of voltage and current sampling points in a method for identifying the operation status of an AC filter group in a converter station disclosed in an embodiment of the present invention; Figure 3 A schematic diagram of the locations of voltage and current sampling points in an experimental case of a method for identifying the operation status of an AC filter group in a converter station disclosed in an embodiment of the present invention; FIG. 4( a ) and FIG. 4( b ) are circuit topology diagrams of an HP3 filter and an HP12 / 24 filter in a method for identifying an operation state of an AC filter group in a converter station disclosed in an embodiment of the present invention. DETAILED DESCRIPTION

[0032] 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 combination with 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.

[0033] Example 1 like Figure 1As shown, Embodiment 1 of the present invention provides a method for identifying the operation status of an AC filter group in a converter station, mainly based on the fact that the actual operation status of the AC filter group in the converter station (i.e., the operation combination of different types of AC filters) is unclear, and only the measured voltage and current can be obtained to obtain the fundamental impedance, harmonic impedance, fundamental reactive power, etc. Therefore, it is necessary to preset the operation status (i.e., preset the operation combination of the AC filter), calculate the fundamental impedance, harmonic impedance, and fundamental reactive power through the measured voltage and the inductance, capacitance, and resistance of the AC filter; compare the fundamental impedance, harmonic impedance, and fundamental reactive power under the preset operation status with the actual operation status, and identify the actual operation status of the AC filter group. After identifying the actual operation status, the mechanism of non-characteristic subharmonic amplification caused by the AC filter group is revealed based on the actual operation status, and the influence of different types and quantities of AC filter combinations on non-characteristic subharmonic amplification is quantified. The method proposed in the present invention specifically includes the following steps: S1. Synchronously collect the RMS value of the fundamental voltage of the AC busbar of the converter station, the RMS value of the harmonic voltage of the concerned frequency, the RMS value of the fundamental current of the AC filter group, and the RMS value of the harmonic current of the concerned frequency. The detailed process of S1 is as follows: like Figure 2 As shown in the figure, the synchronous sampling converter station AC bus A voltage discrete signal in time domain and AC filter group Current time-domain discrete signal ,in, is the number of the sampled voltage and current waveform time domain discrete signal, is the number of the AC filter group. The sampled signal is converted from the time domain to the frequency domain through discrete Fourier transform, and the window width is set to 10 cycles. The specific calculation formula is as follows:

[0034]

[0035]

[0036]

[0037] In the formula, is the RMS value of the AC bus fundamental voltage of the converter station; AC busbar for converter station Subharmonic voltage RMS value; For the The RMS value of the fundamental current of the AC filter group; For the AC filter group Subharmonic current RMS value; The number of sampling points of 10 cycles of the discrete time domain signal of the voltage or current waveform; is the number of the discrete signal in the time domain, and its value range is ; is the number of AC filter groups; is the harmonic order; is an imaginary unit; is a natural constant; Indicates the modulus value of the phase quantity.

[0038] S2. Calculate the fundamental impedance, harmonic impedance of the concerned frequency and fundamental reactive power of the AC filter group under the actual operation state. The detailed process of S2 is as follows: Calculate the actual operation status of the AC filter group fundamental impedance, Subharmonic impedance and fundamental reactive power, the specific formula is as follows:

[0039]

[0040]

[0041] In the formula, The actual operation state Fundamental impedance of AC filter group; The actual operation state AC filter group Subharmonic impedance; The actual operation state Fundamental reactive power of the AC filter group.

[0042] S3, collect the circuit topology and component parameters of the AC filter, and calculate the fundamental impedance and harmonic impedance of the AC filter group under the preset operation state; the detailed process of S3 is as follows: Collect the converter station AC filter circuit topology and component parameters, preset the operation status of the AC filter group, then

[0043]

[0044] In the formula, The first Fundamental impedance of the AC filter group; The first AC filter group Subharmonic impedance; For the Fundamental impedance of the AC filter type; For the AC filter types Subharmonic impedance; For the AC filter group The total number of AC filter types that are expected to be put into operation; is the number of the AC filter type, is the total number of AC filter types.

[0045] S4. Calculate the fundamental reactive power of the AC filter group under the preset operation state according to the RMS value of the fundamental voltage of the AC busbar of the converter station and the fundamental impedance of the AC filter group under the preset operation state. The detailed process of S4 is as follows: According to the RMS value of the AC bus fundamental voltage of the converter station and the first AC filter group fundamental impedance , theoretical derivation of the preset commissioning state The fundamental reactive power of the AC filter group is calculated as follows:

[0046] In the formula, The first Fundamental reactive power of AC filter group. S5, compare the fundamental reactive power, fundamental impedance, and harmonic impedance of the frequency of interest under the actual operation state and the preset operation state, and determine whether the preset operation state of the AC filter group is consistent with the actual operation state. If not, reset the operation state and return to execute S3 to S5 until the actual operation state is consistent with the preset operation state, then the actual operation state of the AC filter is obtained, thereby realizing the identification of the operation state of the AC filter group. The detailed process of S5 is as follows: Calculate the fundamental wave reactive power, fundamental wave impedance, The difference change rate of subharmonic impedance is as follows:

[0047]

[0048]

[0049] In the formula, is the fundamental reactive power difference change rate; For the The rate of change of the fundamental impedance difference of the AC filter group; For the AC filter group Subharmonic impedance difference change rate. like and and , then The actual operation status of the AC filter group is consistent with the preset operation status; if or or , then The actual operation status of the group AC filter is inconsistent with the preset operation status. The threshold value of the difference change rate is set. It is recommended to take 5%, 10%, etc. When the actual operation state of the group AC filter is inconsistent with the preset operation state, it is necessary to reset the operation state until the actual operation state is consistent with the preset operation state, and then the actual combination of the AC filter is obtained.

[0050] In order to better introduce the present invention, a specific experimental case is described in detail below: The wiring diagram of 500kV AC field in a 1100kV converter station is as follows: Figure 3 As shown in the figure, a voltage measuring point is set at the 500kV AC bus, and a current measuring point is set at the output side of the three groups of AC filters. Synchronous acquisition of the AC bus voltage of the converter station: , , ; Group 1 AC filter group: , , ; The second group of AC filter group: , , ; The third group of AC filter group: , , .

[0051] Calculate the first group of AC filter groups under actual operation: , , , ; The second group of AC filter group: , , , ; The third group of AC filter group: , , , .

[0052] The circuit topology and component parameters of the AC filter are collected as shown in Figure 4 (a), Figure 4 (b) and Table 1. Figure 4 (a) is a schematic diagram of a single-tuned filter (abbreviated as HP3), and Figure 4 (b) is a schematic diagram of a double-tuned filter (abbreviated as HP12 / 24).

[0053] Table 1 AC filter component parameters

[0054] The first group of AC filter groups includes two groups of HP12 / 24 and one group of HP3; the second group of AC filter groups includes three groups of HP12 / 24; and the third group of AC filter groups includes three groups of HP12 / 24.

[0055] The fundamental impedance, fifth harmonic impedance, seventh harmonic impedance and fundamental reactive power of the first, second and third AC filter groups under the preset operation state are calculated, as shown in Table 2.

[0056] Table 2 AC filter parameters under preset operation status

[0057] The difference change rate of fundamental reactive power, fundamental impedance, 5th harmonic impedance and 7th harmonic impedance under the actual operation state and the preset operation state is calculated, as shown in Table 3.

[0058] Table 3 Difference change rate parameters

[0059] set up , the first group of AC filter combination is 1 group of HP12 / 24 + 1 group of HP3; the second group of AC filter combination is 3 groups of HP12 / 24; the third group of AC filter combination is 1 group of HP12 / 24.

[0060] Through the above technical scheme, the present invention, on the one hand, uses the voltage and current data of the real-time monitoring of the AC filter group of the converter station to obtain the fundamental impedance, harmonic impedance of the frequency of interest and fundamental reactive power of the AC filter group under the actual operation state; on the other hand, according to the AC filter topology and component parameters of all types of AC filters in the converter station, calculate the fundamental impedance, harmonic impedance of the frequency of interest and fundamental reactive power of the AC filter group under the preset operation state. Finally, the operation combination and quantity of the AC filter group are identified based on the difference change rate between the two. In the case where there is a lack of detailed records of the operation combination and quantity of the AC filter group of the converter station and it is difficult to accurately obtain, this method makes full use of the monitoring data to realize the accurate identification of the operation state of the AC filter of the converter station, which provides reliable support for revealing the mechanism of non-characteristic subharmonic amplification caused by the AC filter group, quantifying the influence of different types and quantities of AC filter combinations on non-characteristic subharmonic amplification, and clarifying the causes of abnormal harmonic states in the converter station.

[0061] Example 2 Based on the first embodiment, the second embodiment of the present invention further provides a system for identifying the operation status of an AC filter group in a converter station, including: A data acquisition module is used to synchronously collect the RMS value of the fundamental voltage of the AC busbar of the converter station, the RMS value of the harmonic voltage of the concerned frequency, the RMS value of the fundamental current of the AC filter group, and the RMS value of the harmonic current of the concerned frequency; The actual operation data calculation module is used to calculate the fundamental impedance, harmonic impedance of the concerned frequency and fundamental reactive power of the AC filter group under the actual operation state based on the data acquisition module; The first preset operation calculation module is used to collect the circuit topology and component parameters of the AC filter, and calculate the fundamental impedance and the harmonic impedance of the concerned frequency of the AC filter group under the preset operation state; The second preset operation calculation module is used to calculate the fundamental reactive power of the AC filter group in the preset operation state according to the RMS value of the fundamental voltage of the AC busbar of the converter station and the fundamental impedance of the AC filter group in the preset operation state; The state identification module is used to compare the fundamental reactive power, fundamental impedance, and harmonic impedance of the frequency of interest under the actual operation state and the preset operation state, and determine whether the preset operation state of the AC filter group is consistent with the actual operation state. If not, the operation state is reset, and the first preset operation calculation module is returned to the state identification module until the actual operation state is consistent with the preset operation state. The actual operation state of the AC filter is obtained, thereby realizing the operation state identification of the AC filter group.

[0062] Specifically, the data acquisition module is also used for:

[0063]

[0064]

[0065]

[0066] In the formula, is the RMS value of the AC bus fundamental voltage of the converter station; AC busbar for converter station Subharmonic voltage RMS value; For the The RMS value of the fundamental current of the AC filter group; For the AC filter group Subharmonic current RMS value; The number of sampling points of 10 cycles of the discrete time domain signal of the voltage or current waveform; is the number of the discrete signal in the time domain, and its value range is ; is the number of AC filter groups; is the harmonic order; is an imaginary unit; is a natural constant; Indicates the modulus value of the phase quantity.

[0067] Specifically, the actual operation data calculation module is also used for: The RMS value of the AC bus fundamental voltage of the converter station is The ratio of the fundamental current root mean square value of the AC filter group is taken as the first AC filter group fundamental impedance; AC busbar of converter station The RMS value of the subharmonic voltage is AC filter group The ratio of the root mean square value of the sub-harmonic current is taken as the first AC filter group harmonic impedance; three times the RMS value of the fundamental voltage of the AC busbar of the converter station and the The product of the root mean square value of the fundamental current of the AC filter group is taken as the first Fundamental reactive power of the AC filter group.

[0068] Specifically, the first preset operation calculation module is also used for: Collect the converter station AC filter circuit topology and component parameters, preset the operation status of the AC filter group, then

[0069]

[0070] In the formula, The first Fundamental impedance of the AC filter group; The first AC filter group Subharmonic impedance; For the Fundamental impedance of the AC filter type; For the AC filter types Subharmonic impedance; For the AC filter group The total number of AC filter types that are expected to be put into operation; is the number of the AC filter type, is the total number of AC filter types.

[0071] Specifically, the second preset operation calculation module is also used for: The square of the three times the RMS value of the AC bus fundamental voltage of the converter station is equal to the The ratio of the fundamental impedance of the AC filter group is used as the first Fundamental reactive power of AC filter group.

[0072] Specifically, the state identification module is also used for: The preset commissioning state and the actual commissioning state The absolute value of the difference between the fundamental reactive power of the AC filter group and the actual operation state The fundamental reactive power ratio of the AC filter group is used as the fundamental reactive power difference change rate. ; The first The difference between the fundamental impedance of the AC filter group and the actual operation state The ratio of the fundamental impedance of the AC filter group is taken as the The change rate of the fundamental impedance difference of the AC filter group ; The first AC filter group The difference between the subharmonic impedance and the actual operation state AC filter group The ratio of subharmonic impedance is taken as the AC filter group Subharmonic impedance difference change rate ; like and and , then The actual operation status of the AC filter group is consistent with the preset operation status; if or or , then The actual operation status of the group AC filter is inconsistent with the preset operation status, among which, The threshold value of the difference change rate is set.

[0073] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for identifying the operation status of an AC filter group in a converter station, characterized in that: include: S1. Synchronously collect the RMS value of the fundamental voltage of the AC busbar of the converter station, the RMS value of the harmonic voltage of the concerned frequency, the RMS value of the fundamental current of the AC filter group, and the RMS value of the harmonic current of the concerned frequency; S2, based on S1, calculates the fundamental impedance, harmonic impedance of the concerned frequency and fundamental reactive power of the AC filter group under the actual operation state; S3, collecting the circuit topology and component parameters of the AC filter, and calculating the fundamental impedance and harmonic impedance of the concerned frequency of the AC filter group under the preset operation state; S4. Calculate the fundamental reactive power of the AC filter group in the preset operation state according to the RMS value of the fundamental voltage of the AC busbar of the converter station and the fundamental impedance of the AC filter group in the preset operation state; S5. Compare the fundamental reactive power, fundamental impedance, and harmonic impedance of the frequency of interest under the actual operation state and the preset operation state to determine whether the preset operation state of the AC filter group is consistent with the actual operation state. If not, reset the operation state and return to execute S3 to S5 until the actual operation state is consistent with the preset operation state. Then, the actual operation state of the AC filter is obtained, thereby realizing the identification of the operation state of the AC filter group.

2. A method for identifying the operation status of an AC filter group in a converter station according to claim 1, characterized in that: S1 includes: In the formula, For synchronous sampling of the converter station AC bus A voltage time-domain discrete signal, For the AC filter group A current discrete signal in time domain, is the RMS value of the AC bus fundamental voltage of the converter station; AC busbar for converter station Subharmonic voltage RMS value; For the The RMS value of the fundamental current of the AC filter group; For the AC filter group Subharmonic current RMS value; The number of sampling points of 10 cycles of the discrete time domain signal of the voltage or current waveform; is the number of the discrete signal in the time domain, and its value range is ; is the number of AC filter groups; is the harmonic order; is an imaginary unit; is a natural constant; Indicates the modulus value of the phase quantity.

3. A method for identifying the operation status of an AC filter group in a converter station according to claim 1, characterized in that S2 include: The RMS value of the AC bus fundamental voltage of the converter station is The ratio of the fundamental current root mean square value of the AC filter group is taken as the first AC filter group fundamental impedance; AC busbar of converter station The RMS value of the subharmonic voltage is AC filter group The ratio of the root mean square value of the sub-harmonic current is taken as the first AC filter group harmonic impedance; three times the RMS value of the fundamental voltage of the AC busbar of the converter station and the The product of the root mean square value of the fundamental current of the AC filter group is taken as the first Fundamental reactive power of the AC filter group.

4. A method for identifying the operation status of an AC filter group in a converter station according to claim 1, characterized in that S3 include: Collect the converter station AC filter circuit topology and component parameters, preset the operation status of the AC filter group, then In the formula, The first Fundamental impedance of the AC filter group; The first AC filter group Subharmonic impedance; For the Fundamental impedance of the AC filter type; For the AC filter types Subharmonic impedance; For the AC filter group The total number of AC filter types that are expected to be put into operation; is the number of the AC filter type, is the total number of AC filter types.

5. The method for identifying the operation status of the AC filter group of a converter station according to claim 1, characterized in that S4 include: The square of the three times the RMS value of the AC bus fundamental voltage of the converter station is equal to the The ratio of the fundamental impedance of the AC filter group is used as the first Fundamental reactive power of AC filter group.

6. A method for identifying the operation status of an AC filter group in a converter station according to claim 1, characterized in that S5 include: The preset commissioning state and the actual commissioning state The absolute value of the difference between the fundamental reactive power of the AC filter group and the actual operation state The fundamental reactive power ratio of the AC filter group is used as the fundamental reactive power difference change rate. ; The first The difference between the fundamental impedance of the AC filter group and the actual operation state The ratio of the fundamental impedance of the AC filter group is taken as the The change rate of the fundamental impedance difference of the AC filter group ; The first AC filter group The difference between the subharmonic impedance and the actual operation state AC filter group The ratio of subharmonic impedance is taken as the AC filter group Subharmonic impedance difference change rate ; like and and , then The actual operation status of the AC filter group is consistent with the preset operation status; if or or , then The actual operation status of the group AC filter is inconsistent with the preset operation status, among which, The threshold value of the difference change rate is set.

7. A converter station AC filter group operation status identification system, characterized in that: include: A data acquisition module is used to synchronously collect the RMS value of the fundamental voltage of the AC busbar of the converter station, the RMS value of the harmonic voltage of the concerned frequency, the RMS value of the fundamental current of the AC filter group, and the RMS value of the harmonic current of the concerned frequency; The actual operation data calculation module is used to calculate the fundamental impedance, harmonic impedance of the concerned frequency and fundamental reactive power of the AC filter group under the actual operation state based on the data acquisition module; The first preset operation calculation module is used to collect the circuit topology and component parameters of the AC filter, and calculate the fundamental impedance and the harmonic impedance of the concerned frequency of the AC filter group under the preset operation state; The second preset operation calculation module is used to calculate the fundamental reactive power of the AC filter group in the preset operation state according to the RMS value of the fundamental voltage of the AC busbar of the converter station and the fundamental impedance of the AC filter group in the preset operation state; The state identification module is used to compare the fundamental reactive power, fundamental impedance, and harmonic impedance of the frequency of interest under the actual operation state and the preset operation state, and determine whether the preset operation state of the AC filter group is consistent with the actual operation state. If not, the operation state is reset, and the first preset operation calculation module is returned to the state identification module until the actual operation state is consistent with the preset operation state. The actual operation state of the AC filter is obtained, thereby realizing the operation state identification of the AC filter group.

8. The system for identifying the operation status of the AC filter group of a converter station according to claim 7, characterized in that: The data acquisition module is also used to: In the formula, For synchronous sampling of the converter station AC bus A voltage time-domain discrete signal, For the AC filter group A current discrete signal in time domain, is the RMS value of the AC bus fundamental voltage of the converter station; AC busbar for converter station Subharmonic voltage RMS value; For the The RMS value of the fundamental current of the AC filter group; For the AC filter group Subharmonic current RMS value; The number of sampling points of 10 cycles of the discrete time domain signal of the voltage or current waveform; is the number of the discrete signal in the time domain, and its value range is ; is the number of AC filter groups; is the harmonic order; is an imaginary unit; is a natural constant; Indicates the modulus value of the phase quantity.

9. The system for identifying the operation status of the AC filter group of a converter station according to claim 7, characterized in that: The actual operation data calculation module is also used for: The RMS value of the AC bus fundamental voltage of the converter station is The ratio of the fundamental current root mean square value of the AC filter group is taken as the first AC filter group fundamental impedance; AC busbar of converter station The RMS value of the subharmonic voltage is AC filter group The ratio of the root mean square value of the sub-harmonic current is taken as the first AC filter group harmonic impedance; three times the RMS value of the fundamental voltage of the AC busbar of the converter station and the The product of the root mean square value of the fundamental current of the AC filter group is taken as the first Fundamental reactive power of the AC filter group.

10. The system for identifying the operation status of the AC filter group of a converter station according to claim 7, characterized in that: The first preset operation calculation module is also used for: Collect the converter station AC filter circuit topology and component parameters, preset the operation status of the AC filter group, then In the formula, The first Fundamental impedance of the AC filter group; The first AC filter group Subharmonic impedance; For the Fundamental impedance of the AC filter type; For the AC filter types Subharmonic impedance; For the AC filter group The total number of AC filter types that are expected to be put into operation; is the number of the AC filter type, is the total number of AC filter types.

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