Distributed phase modifier third harmonic zero voltage stator grounding protection method and device

Abstract

The invention provides a third harmonic zero-voltage stator grounding protection method and device for a distributed phase modifier. The method comprises the following steps: collecting closing position information and machine end analog quantity information of a machine end circuit breaker and a static reactive compensator; based on analog quantity information, third harmonic components, reactive power and frequency of the zero-sequence voltage of the computer end and the zero-sequence voltage of the neutral point; a working condition follow-up regulation criterion is formed, and a third harmonic voltage ratio constant value before grid connection and a third harmonic voltage ratio constant value after grid connection are automatically switched based on the working condition follow-up regulation criterion; forming a power follow-up regulation criterion, and determining a third harmonic voltage ratio calculation constant value based on the power follow-up regulation criterion; and determining whether a third harmonic zero-voltage stator grounding protection action condition is satisfied based on the grounding protection criterion. According to the invention, the operation condition of the unit can be quickly identified, the corresponding protection setting value is automatically switched, and the protection flexibility is improved. The power follow-up regulation criterion is braked through a reactive power per unit value, and the protection reliability under different operation conditions is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of relay protection of power systems, and in particular to a method and device for third harmonic zero-voltage stator grounding protection of a distributed phase regulator. Background Art

[0002] Large-scale phase-converters are non-salient pole machines, with fixed wiring and neutral point grounding methods, and no machine-side circuit breakers. Distributed phase-converters include salient pole machines and non-salient pole machines. The main wiring method and neutral point grounding method are not fixed and are different from large-scale phase-converters. They have machine-side circuit breakers. When the machine-side circuit breaker is disconnected, the calculation of the third harmonic voltage ratio only considers the influence of the machine-side and neutral point distributed capacitance. When the machine-side circuit breaker is closed, the calculation of the third harmonic voltage ratio also considers the influence of the system-side capacitance such as the main transformer, excitation transformer, and busbar. In addition, most machine-side circuit breakers are equipped with parallel capacitors on both sides to prevent overvoltage. Therefore, the third harmonic voltage ratio is quite different before and after the unit is connected to the grid, and the corresponding protection setting value needs to be set according to different working conditions.

[0003] The rotor winding magnetomotive force and the stator winding magnetomotive force work together to generate the third harmonic flux of the air gap magnetic field of the distributed phase condenser. There is no armature reaction before grid connection, and the third harmonic at the machine end is the third harmonic component of the machine end voltage. After grid connection with load, the armature reaction saturates the magnetic circuit and generates the third harmonic potential. The flux generated by the active power armature reaction is located in the q-axis direction of the phase condenser, and the flux generated by the reactive power armature reaction is located in the d-axis direction of the phase condenser. For salient pole distributed phase condensers, the air gap in the d-axis direction is small and easy to saturate. Therefore, reactive power has a greater impact on the third harmonic potential of salient pole distributed phase condensers. The third harmonic voltage ratio is different at different reactive powers, which reduces the reliability of the conventional third harmonic voltage ratio criterion. Therefore, a third harmonic zero-voltage stator grounding protection method that is applicable to both hidden pole and salient pole distributed phase condensers should be studied specifically for distributed phase condensers. Summary of the invention

[0004] In view of this, the present invention provides a method and device for third harmonic zero-voltage stator grounding protection of a distributed phase-converter to solve at least one of the above-mentioned problems.

[0005] In order to achieve the above object, the present invention adopts the following scheme:

[0006] According to a first aspect of the present invention, a method for third harmonic zero-voltage stator grounding protection of a distributed phase-converting machine is provided, the method comprising: collecting the closing position information of the distributed phase-converting machine-side circuit breaker, the closing position information of the static VAR compensator and the machine-side analog quantity information; based on the machine-side analog quantity information, the third harmonic components of the zero-sequence voltage and the neutral point zero-sequence voltage, the unit reactive power and the unit frequency of the computer-side; according to the closing position information of the machine-side circuit breaker, the closing position information of the static VAR compensator and the unit frequency, a working condition adjustment criterion is formed, and the third harmonic before and after the grid connection is automatically switched based on the working condition adjustment criterion. voltage ratio constant; obtaining a reactive power per unit value based on the reactive power of the unit; constituting a power adjustment criterion according to the reactive power per unit value, the third harmonic voltage ratio constant, a preset reliability coefficient and a preset power adjustment control word, and determining a third harmonic voltage ratio calculation constant based on the power adjustment criterion; constituting a grounding protection criterion based on the third harmonic voltage ratio calculation constant, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, and judging whether the third harmonic zero-voltage stator grounding protection action condition is met based on the grounding protection criterion.

[0007] As an embodiment of the present invention, the machine-end analog quantity information in the above method includes: sampling values ​​of the machine-end three-phase voltage, the machine-end three-phase current, the machine-end zero-sequence voltage and the neutral point zero-sequence voltage.

[0008] As an embodiment of the present invention, the above method, based on the machine-end analog information, the computer-end zero-sequence voltage and the third harmonic component of the neutral point zero-sequence voltage, the unit reactive power and the unit frequency include: using the sampling values ​​of the machine-end zero-sequence voltage and the neutral point zero-sequence voltage to calculate the third harmonic component of the machine-end zero-sequence voltage and the third harmonic component of the neutral point zero-sequence voltage through Fourier algorithm and digital filter algorithm; using the sampling values ​​of the machine-end three-phase voltage and the machine-end three-phase current to calculate the unit reactive power through Fourier algorithm and reactive power algorithm; using the sampling values ​​of the machine-end three-phase voltage to calculate the unit frequency through hardware frequency measurement algorithm or software frequency measurement algorithm.

[0009] As an embodiment of the present invention, in the above method, the operating condition adjustment criterion is formed according to the closing position information of the machine-end circuit breaker, the closing position information of the static VAR compensator and the unit frequency, and the third harmonic voltage ratio setting value before and after grid connection is automatically switched based on the operating condition adjustment criterion, including: when the closing position information of the machine-end circuit breaker is 1, the closing position information of the static VAR compensator is 0, and the unit frequency is greater than the set frequency, the unit grid connection state is judged to be 1, and the closing position information of the machine-end circuit breaker is 1, indicating that there is a machine-end circuit breaker. The closing position is switched in, the closing position information of the static reactive power compensator is 0, indicating that there is no static reactive power compensator closing position switched in, and the unit grid-connected state is 1, indicating that the unit is in the grid-connected state; when the closing position of the machine-side circuit breaker is 0 or the closing position of the static reactive power compensator is 1, the delay judgment is that the unit grid-connected state is 0, the closing position of the machine-side circuit breaker is 0, indicating that there is no machine-side circuit breaker closing position switched in, the closing position of the static reactive power compensator is 1, indicating that there is a static reactive power compensator closing position switched in, and the unit grid-connected state is 0, indicating that the unit is not in the grid-connected state;

[0010] The following working condition adjustment criterion is constructed:

[0011]

[0012] In the above formula, K Set is the third harmonic voltage ratio constant, K BeforeSet K is the third harmonic voltage ratio constant before grid connection, AfterSet The third harmonic voltage ratio setting value after grid connection, the working condition adjustment control word is an adjustable control word. When the difference of the measured third harmonic voltage ratio before and after the distributed phase regulator is connected to the grid exceeds the set threshold, the working condition adjustment control word is set to 1, otherwise, the working condition adjustment control word is set to 0;

[0013] Based on the working condition adjustment criterion, the K after the output fixed value is automatically switched Set value.

[0014] As an embodiment of the present invention, obtaining the reactive power per unit value based on the reactive power of the unit in the above method includes:

[0015] Based on the reactive power of the unit, the reactive power per unit value is obtained using the following formula:

[0016]

[0017] In the above formula, Q * is the reactive power per unit value, Q N is the rated capacity of the distributed phase-converter, and Q is the reactive power of the unit.

[0018] As an embodiment of the present invention, in the above method, the reactive power per unit value, the third harmonic voltage ratio constant, the preset reliability coefficient and the preset power adjustment control word form a power adjustment criterion, and the third harmonic voltage ratio calculation constant is determined based on the power adjustment criterion, including:

[0019] According to the reactive power per unit value, the third harmonic voltage ratio constant, the preset reliability coefficient and the preset power adjustment control word, the following power adjustment criterion is formed:

[0020]

[0021] In the above formula: K jsSet is the third harmonic voltage ratio calculation constant, k r is the reliability coefficient, k r The adjustable range is 0.01~0.2, the power adjustment control word is an adjustable control word, when the distributed phase regulator is a salient pole machine, the power adjustment control word is set to 1, when it is a hidden pole machine, the power adjustment control word is set to 0.

[0022] As an embodiment of the present invention, in the above method, a grounding protection criterion is formed based on the third harmonic voltage ratio calculation constant, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, and judging whether the third harmonic zero-voltage stator grounding protection action condition is met based on the grounding protection criterion includes:

[0023] Based on the calculated constant value of the third harmonic voltage ratio, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, a grounding protection criterion as shown in the following formula is formed:

[0024]

[0025] In the above formula: is the third harmonic component of the zero-sequence voltage at the machine end, U n3 is the amplitude of the third harmonic component of the neutral point zero-sequence voltage; n TV3 is the PT transformation ratio of the neutral point zero-sequence voltage; n TV1 is the PT transformation ratio of the zero-sequence voltage at the machine end;

[0026] When the ground protection criterion meets the action conditions, after a delay T set , it is determined that the third harmonic zero-voltage stator grounding protection has been activated.

[0027] According to a second aspect of the present invention, a distributed phase-converter third harmonic zero-voltage stator grounding protection device is provided, and the device comprises: an information acquisition unit, used to acquire the closing position information of the distributed phase-converter machine-side circuit breaker, the closing position information of the static VAR compensator and the machine-side analog quantity information; a data calculation unit, used to calculate the third harmonic components of the zero-sequence voltage and the neutral point zero-sequence voltage, the unit reactive power and the unit frequency based on the machine-side analog quantity information; an operating condition adjustment unit, used to form an operating condition adjustment criterion according to the closing position information of the machine-side circuit breaker, the closing position information of the static VAR compensator and the unit frequency, and automatically switch the third harmonic voltage before and after grid connection based on the operating condition adjustment criterion Ratio constant; a per-unit value acquisition unit, used to obtain the reactive power per-unit value based on the reactive power of the unit; a calculated constant determination unit, used to form a power adjustment criterion according to the reactive power per-unit value, the third harmonic voltage ratio constant, a preset reliability coefficient and a preset power adjustment control word, and determine the third harmonic voltage ratio calculated constant based on the power adjustment criterion; a grounding protection judgment unit, used to form a grounding protection criterion based on the third harmonic voltage ratio calculated constant, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, and judge whether the third harmonic zero-voltage stator grounding protection action condition is met based on the grounding protection criterion.

[0028] As an embodiment of the present invention, the above-mentioned machine-end analog quantity information includes: sampling values ​​of the machine-end three-phase voltage, the machine-end three-phase current, the machine-end zero-sequence voltage and the neutral point zero-sequence voltage.

[0029] As an embodiment of the present invention, the above-mentioned data calculation unit includes: a harmonic component calculation module, which is used to use the sampling values ​​of the machine-end zero-sequence voltage and the neutral point zero-sequence voltage to calculate the third harmonic component of the machine-end zero-sequence voltage and the third harmonic component of the neutral point zero-sequence voltage through Fourier algorithm and digital filter algorithm; a reactive power calculation module, which is used to use the sampling values ​​of the machine-end three-phase voltage and the machine-end three-phase current to calculate the reactive power of the unit through Fourier algorithm and reactive power algorithm; a frequency calculation module, which is used to use the sampling values ​​of the machine-end three-phase voltage to calculate the unit frequency through hardware frequency measurement algorithm or software frequency measurement algorithm.

[0030] As an embodiment of the present invention, the above-mentioned working condition adjustment unit is specifically used for: when the closing position information of the machine-side circuit breaker is 1, the closing position information of the static reactive power compensator is 0, and the unit frequency is greater than the set frequency, the unit grid-connected state is judged to be 1, the machine-side circuit breaker closing position information is 1, indicating that the machine-side circuit breaker closing position is opened, the static reactive power compensator closing position information is 0, indicating that the static reactive power compensator closing position is not opened, and the unit grid-connected state is 1, indicating that the unit is in the grid-connected state; when the machine-side circuit breaker closing position is 0 or the static reactive power compensator closing position is 1, the delay judgment is that the unit grid-connected state is 0, the machine-side circuit breaker closing position is 0, indicating that the machine-side circuit breaker closing position is not opened, the static reactive power compensator closing position is 1, indicating that the static reactive power compensator closing position is opened, and the unit grid-connected state is 0, indicating that the unit is not in the grid-connected state;

[0031] The following working condition adjustment criterion is constructed:

[0032]

[0033] In the above formula, K Set is the third harmonic voltage ratio constant, K BeforeSet K is the third harmonic voltage ratio constant before grid connection, AfterSet The third harmonic voltage ratio setting value after grid connection, the working condition adjustment control word is an adjustable control word. When the difference of the measured third harmonic voltage ratio before and after the distributed phase regulator is connected to the grid exceeds the set threshold, the working condition adjustment control word is set to 1, otherwise, the working condition adjustment control word is set to 0;

[0034] Based on the working condition adjustment criterion, the K after the output fixed value is automatically switched Set value.

[0035] As an embodiment of the present invention, the above-mentioned per unit value acquisition unit is specifically used to: based on the reactive power of the unit, obtain the per unit value of reactive power using the following formula:

[0036]

[0037] In the above formula, Q * is the reactive power per unit value, Q N is the rated capacity of the distributed phase-converter, and Q is the reactive power of the unit.

[0038] As an embodiment of the present invention, the above-mentioned calculation constant determination unit is specifically used to: form the following power adjustment criterion according to the reactive power per unit value, the third harmonic voltage ratio constant, the preset reliability coefficient and the preset power adjustment control word:

[0039]

[0040] In the above formula: K jsSetis the third harmonic voltage ratio calculation constant, k r is the reliability coefficient, k r The adjustable range is 0.01~0.2, the power adjustment control word is an adjustable control word, when the distributed phase regulator is a salient pole machine, the power adjustment control word is set to 1, when it is a hidden pole machine, the power adjustment control word is set to 0.

[0041] As an embodiment of the present invention, the grounding protection judgment unit is specifically used to: calculate the fixed value based on the third harmonic voltage ratio, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage to form a grounding protection criterion as shown in the following formula:

[0042]

[0043] In the above formula: is the third harmonic component of the zero-sequence voltage at the machine end, U n3 is the amplitude of the third harmonic component of the neutral point zero-sequence voltage; n TV3 is the PT transformation ratio of the neutral point zero-sequence voltage; n TV1 is the PT transformation ratio of the zero-sequence voltage at the machine end;

[0044] When the ground protection criterion meets the action conditions, after a delay T set , it is determined that the third harmonic zero-voltage stator grounding protection has been activated.

[0045] According to a third aspect of the present invention, there is provided an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0046] According to a fourth aspect of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0047] The third harmonic zero-voltage stator grounding protection method and device for distributed phase-shifting machine proposed in the present invention can quickly identify the operating conditions of the unit (before or after grid connection) through the operating condition adjustment criterion, and automatically switch the corresponding protection setting value, thereby avoiding false operation or refusal of protection due to changes in operating conditions and improving the flexibility of protection. The power adjustment criterion further improves the protection reliability under different operating conditions through reactive power per unit braking. In addition, the present application is applicable to both salient-pole and non-salient-pole distributed phase-shifting machines, as well as various situations with organic-end circuit breakers and inorganic-end circuit breakers, and has a wide range of applications and is suitable for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. 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 creative work. In the drawings:

[0049] Figure 1 It is a flow chart of a method for third harmonic zero-voltage stator grounding protection of a distributed phase regulator provided in an embodiment of the present application;

[0050] Figure 2 It is a schematic diagram of a process for calculating relevant information based on machine-side analog quantity information provided in an embodiment of the present application;

[0051] Figure 3 It is a schematic diagram of a flow chart of automatically switching a fixed value based on an operating condition adjustment criterion provided by an embodiment of the present invention;

[0052] Figure 4 It is a structural schematic diagram of a distributed phase-converter third harmonic zero-voltage stator grounding protection device provided in an embodiment of the present application;

[0053] Figure 5 is a structural diagram of a data calculation unit provided in an embodiment of the present application;

[0054] Figure 6 It is a structural schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0055] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0056] like Figure 1 The figure shows a flow chart of a distributed phase-converter third harmonic zero-voltage stator grounding protection method provided by an embodiment of the present application. This embodiment describes the present application from the side of the grounding protection device. The method includes the following steps:

[0057] Step S101: Collect the closing position information of the circuit breaker at the generator end of the distributed phase condenser, the closing position information of the static VAR compensator (SFC), and the analog quantity information at the generator end.

[0058] In this embodiment, the closing position information can be obtained through the auxiliary contacts of the machine-side circuit breaker and the static VAR compensator, where the closing position information is the switch state of the knife switch. Specifically, the position information in this embodiment can be represented by "0" and "1", where "1" represents the closing (closed) of the circuit breaker and the SFC closing, and "0" represents the opening (open) of the circuit breaker and the SFC opening.

[0059] Preferably, the machine-end analog quantity information collected in this step includes: sampling values ​​of machine-end three-phase voltage, machine-end three-phase current, machine-end zero-sequence voltage and neutral point zero-sequence voltage. The machine-end three-phase voltage refers to the three-phase voltage at the connection point of the distributed phase-shifting machine, the machine-end three-phase current refers to the three-phase current flowing through the connection point of the distributed phase-shifting machine, the machine-end zero-sequence voltage refers to the zero-sequence component of the machine-end three-phase voltage, and the neutral point zero-sequence voltage refers to the zero-sequence voltage at the neutral point of the power system, and the neutral point is the common point of the three-phase power supply.

[0060] Specifically, the above-mentioned machine-side analog quantity information can be obtained by collecting the electrical quantities of the common voltage transformer, machine-side current transformer, neutral point voltage transformer and other devices at the distributed phase modulator machine end, and then connecting them to the grounding protection device through cables.

[0061] Step S102: Based on the machine-end analog quantity information, the third harmonic component of the computer-end zero-sequence voltage and the neutral point zero-sequence voltage, the unit reactive power and the unit frequency are calculated.

[0062] Preferably, Figure 2 As shown, this step may further include the following sub-steps:

[0063] Step S1021: using the sampling values ​​of the machine-end zero-sequence voltage and the neutral point zero-sequence voltage, the third harmonic component of the machine-end zero-sequence voltage and the third harmonic component of the neutral point zero-sequence voltage are calculated through Fourier algorithm and digital filter algorithm.

[0064] First, the collected zero-sequence voltage sampling values ​​and neutral point zero-sequence voltage sampling values ​​can be preprocessed, such as removing DC components and filtering high-frequency noise, etc. This can improve the accuracy of subsequent Fourier transform. Commonly used preprocessing methods include average filtering, median filtering, etc.

[0065] Then, the fast Fourier transform (FFT) algorithm is used to convert the zero-sequence voltage sampling value in the time domain into frequency domain data. The FFT algorithm can efficiently calculate the discrete Fourier transform and decompose the signal into sinusoidal wave components of different frequencies.

[0066] Since the result of FFT contains various frequency components, this embodiment continues to use a digital filter (such as a bandpass filter) to extract the third harmonic component (the frequency is three times the fundamental frequency). Appropriate filter parameters need to be set here to accurately separate the third harmonic and suppress other frequency components.

[0067] Finally, the third harmonic component of the zero-sequence voltage at the machine end and the third harmonic component of the zero-sequence voltage at the neutral point are extracted from the filtered results.

[0068] Step S1022: using the sampled values ​​of the three-phase voltage and the three-phase current at the machine end, the reactive power of the machine set is obtained through Fourier algorithm and reactive power algorithm.

[0069] Similarly, similar to step S1021, the sampled values ​​of the three-phase voltage and the three-phase current at the machine end may be preprocessed to remove the DC component and noise.

[0070] Then the FFT algorithm is used to convert the three-phase voltage and current sampling values ​​in the time domain into frequency domain data.

[0071] Then, based on the frequency domain data, the reactive power of the unit is calculated using the reactive power calculation formula. Commonly used formulas here include instantaneous power theory or calculation methods based on the phasor method, which specifically need to consider the amplitude and phase relationship of voltage and current.

[0072] Finally, the calculated reactive power value of the unit is output.

[0073] Step S1023: using the sampling value of the three-phase voltage at the machine end, the frequency of the machine unit is obtained by a hardware frequency measurement algorithm or a software frequency measurement algorithm.

[0074] The goal of this step is to calculate the frequency of the unit from the sampled values ​​of the three-phase voltage at the machine end. The hardware frequency measurement algorithm refers to some special hardware that can directly measure the frequency, such as a frequency meter. This method is usually more accurate and faster. The software frequency measurement algorithm is usually based on FFT or other signal processing techniques. For example, the FFT algorithm can be used to calculate the main frequency component of the voltage signal, and the frequency of this component is the unit frequency. Other algorithms, such as the zero-crossing detection method, can also be used for frequency measurement. It should be pointed out that the accuracy and speed of the software frequency measurement algorithm depend on the algorithm itself and the sampling frequency.

[0075] The above three sub-steps S1021-S1023 together complete the process from raw sampling data to key parameter extraction, providing the necessary data basis for subsequent protection criterion calculation. Each sub-step relies on precise signal processing technology and algorithms to ensure the accuracy and reliability of the calculation results.

[0076] Step S103: forming an operating condition adjustment criterion according to the closing position information of the machine-end circuit breaker, the closing position information of the static VAR compensator and the unit frequency, and automatically switching the third harmonic voltage ratio constant before and after grid connection based on the operating condition adjustment criterion.

[0077] Preferably, Figure 3 As shown, this step may specifically include:

[0078] Step S1031: First, determine the grid-connected state of the unit according to the closing position information of the circuit breaker at the unit end, the closing position information of the static VAR compensator and the unit frequency.

[0079] When the closing position information of the machine-side circuit breaker is 1, the closing position information of the static reactive power compensator is 0, and the unit frequency is greater than the set frequency, the unit grid-connected state is determined to be 1. The closing position information of the machine-side circuit breaker is 1, indicating that the machine-side circuit breaker is in the closing position (closed), and the closing position information of the static reactive power compensator is 0, indicating that there is no closing position of the static reactive power compensator (open). The unit grid-connected state is 1, indicating that the unit is in the grid-connected state.

[0080] When the closing position of the machine-side circuit breaker is 0 or the closing position of the static reactive power compensator is 1, the delay judgment is that the unit grid-connected state is 0. The closing position of the machine-side circuit breaker is 0, indicating that the closing position of the machine-side circuit breaker is not opened. The closing position of the static reactive power compensator is 1, indicating that the closing position of the static reactive power compensator is opened. The unit grid-connected state is 0, indicating that the unit is not in the grid-connected state.

[0081] Step S1032: constructing a working condition adjustment criterion based on the grid-connected state of the unit, and the working condition adjustment criterion is shown in the following formula:

[0082]

[0083] In the above formula, K Set is the third harmonic voltage ratio constant, K BeforeSet K is the third harmonic voltage ratio constant before grid connection, AfterSet The third harmonic voltage ratio setting value after grid connection, the operating condition adjustment control word is an adjustable control word. When the difference in the measured third harmonic voltage ratio before and after the distributed phase regulator is grid-connected exceeds the set threshold, the operating condition adjustment control word is set to 1, otherwise, the operating condition adjustment control word is set to 0. At the same time, for occasions without machine-side circuit breakers, the machine-side circuit breaker closing position information is not collected, and the operating condition adjustment control word is set to 0.

[0084] Step S1033: Output the third harmonic voltage ratio constant (K) after the constant is automatically switched based on the working condition adjustment criterion Set value).

[0085] It can be seen that the above steps S1031-S1033 realize the function of dynamically adjusting the protection setting value according to the grid-connected state of the unit and the difference in the third harmonic voltage ratio before and after grid-connection, thereby improving the adaptability and reliability of grounding protection.

[0086] Step S104: obtaining a reactive power per unit value based on the reactive power of the unit.

[0087] Preferably, this step can specifically obtain the reactive power per unit value based on the reactive power of the unit using the following formula:

[0088]

[0089] In the above formula, Q * is the reactive power per unit value, Q N is the rated capacity of the distributed phase-converter, and Q is the reactive power of the unit.

[0090] Step S105: construct a power adjustment criterion according to the reactive power per unit value, the third harmonic voltage ratio constant, a preset reliability coefficient and a preset power adjustment control word, and determine the third harmonic voltage ratio calculation constant based on the power adjustment criterion.

[0091] Preferably, this step may specifically include: forming the following power adjustment criterion according to the reactive power per unit value, the third harmonic voltage ratio constant, the preset reliability coefficient and the preset power adjustment control word:

[0092]

[0093] In the above formula: K jsSet is the third harmonic voltage ratio calculation constant, k r is the reliability coefficient, k r The adjustable range is 0.01~0.2, the power adjustment control word is an adjustable control word, when the distributed phase regulator is a salient pole machine, the power adjustment control word is set to 1, when it is a hidden pole machine, the power adjustment control word is set to 0.

[0094] The core idea of ​​the above power adjustment criterion is to dynamically adjust the power output according to the unit type and operating status. By introducing the reliability coefficient and the power adjustment control word, flexible adjustments can be made according to different machine models and operating conditions. Salient pole machines and hidden pole machines have different operating characteristics, so different control strategies are required. The reliability coefficient allows the conservativeness of the control strategy to be adjusted according to actual conditions. This allows the application to adapt to different operating environments and unit types.

[0095] Step S106: A grounding protection criterion is formed based on the calculated constant of the third harmonic voltage ratio, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, and based on the grounding protection criterion, it is determined whether the third harmonic zero-voltage stator grounding protection action conditions are met.

[0096] Preferably, this step may specifically include: based on the third harmonic voltage ratio calculation constant, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, a grounding protection criterion as shown in the following formula is formed:

[0097]

[0098] In the above formula: is the third harmonic component of the zero-sequence voltage at the machine end, U n3 is the amplitude of the third harmonic component of the neutral point zero-sequence voltage; n TV3 is the PT transformation ratio of the neutral point zero-sequence voltage; n TV1 is the PT transformation ratio of the zero-sequence voltage at the machine end;

[0099] When the ground protection criterion meets the action conditions, after a delay T set , it is determined that the third harmonic zero-voltage stator grounding protection has been activated, and the control word can be used to select tripping or sending a signal.

[0100] It can be seen from the above technical scheme that the third harmonic zero-voltage stator grounding protection method for distributed phase-shifting machines proposed in the present invention can quickly identify the operating conditions of the unit (before or after grid connection) through the operating condition adjustment criterion, and automatically switch the corresponding protection setting value, thereby avoiding misoperation or refusal of protection due to changes in operating conditions and improving the flexibility of protection. The power adjustment criterion further improves the protection reliability under different operating conditions through reactive power per unit braking. In addition, the present application is applicable to both salient-pole and non-salient-pole distributed phase-shifting machines, as well as various situations with organic-end circuit breakers and inorganic-end circuit breakers, and has a wide range of applications and is suitable for promotion and application.

[0101] like Figure 4 The structure diagram of a third harmonic zero-voltage stator grounding protection device for a distributed phase-converter provided in an embodiment of the present application is shown, and the device includes: an information acquisition unit 410, a data calculation unit 420, an operating condition adjustment unit 430, a per-unit value acquisition unit 440, a calculation constant value determination unit 450 and a grounding protection judgment unit 460, which are sequentially connected. Among them:

[0102] The information collection unit 410 is used to collect the closing position information of the circuit breaker at the generator end of the distributed phase modulator, the closing position information of the static VAR compensator and the analog quantity information at the generator end.

[0103] The data calculation unit 420 is used to calculate the third harmonic components of the computer-side zero-sequence voltage and the neutral point zero-sequence voltage, the unit reactive power and the unit frequency based on the unit-side analog quantity information.

[0104] The operating condition adjustment unit 430 is used to form an operating condition adjustment criterion according to the closing position information of the machine-end circuit breaker, the closing position information of the static VAR compensator and the unit frequency, and automatically switch the third harmonic voltage ratio constant before and after grid connection based on the operating condition adjustment criterion.

[0105] The per-unit value acquisition unit 440 is used to obtain the per-unit value of reactive power based on the reactive power of the unit.

[0106] The calculation constant determination unit 450 is used to form a power adjustment criterion according to the reactive power standard value, the third harmonic voltage ratio constant, a preset reliability coefficient and a preset power adjustment control word, and determine the third harmonic voltage ratio calculation constant based on the power adjustment criterion.

[0107] The grounding protection judgment unit 460 is used to form a grounding protection criterion based on the calculated constant of the third harmonic voltage ratio, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, and to judge whether the third harmonic zero-voltage stator grounding protection action condition is met based on the grounding protection criterion.

[0108] Preferably, the above-mentioned machine-end analog quantity information includes: sampling values ​​of the machine-end three-phase voltage, the machine-end three-phase current, the machine-end zero-sequence voltage and the neutral point zero-sequence voltage.

[0109] Preferably, Figure 5 As shown, the data calculation unit 420 may further include:

[0110] The harmonic component calculation module 421 is used to use the sampling values ​​of the machine-end zero-sequence voltage and the neutral point zero-sequence voltage to calculate the third harmonic component of the machine-end zero-sequence voltage and the third harmonic component of the neutral point zero-sequence voltage through Fourier algorithm and digital filter algorithm.

[0111] The reactive power calculation module 422 is used to obtain the reactive power of the unit by using the sampling values ​​of the three-phase voltage and the three-phase current at the unit end through Fourier algorithm and reactive power algorithm.

[0112] The frequency calculation module 423 is used to obtain the unit frequency by using the sampling value of the three-phase voltage at the machine end through a hardware frequency measurement algorithm or a software frequency measurement algorithm.

[0113] Preferably, the above-mentioned working condition adjustment unit 430 is specifically used for: when the closing position information of the machine-side circuit breaker is 1, the closing position information of the static reactive power compensator is 0, and the unit frequency is greater than the set frequency, the unit grid-connected state is determined to be 1, the machine-side circuit breaker closing position information is 1, indicating that the machine-side circuit breaker closing position is switched in, the static reactive power compensator closing position information is 0, indicating that the static reactive power compensator closing position is not switched in, and the unit grid-connected state is 1, indicating that the unit is in the grid-connected state; when the machine-side circuit breaker closing position is 0 or the static reactive power compensator closing position is 1, the delay judgment is that the unit grid-connected state is 0, the machine-side circuit breaker closing position is 0, indicating that the machine-side circuit breaker closing position is not switched in, the static reactive power compensator closing position is 1, indicating that the static reactive power compensator closing position is switched in, and the unit grid-connected state is 0, indicating that the unit is not in the grid-connected state;

[0114] The following working condition adjustment criterion is constructed:

[0115]

[0116] In the above formula, K Set is the third harmonic voltage ratio constant, K BeforeSet K is the third harmonic voltage ratio constant before grid connection, AfterSet The third harmonic voltage ratio setting value after grid connection, the working condition adjustment control word is an adjustable control word. When the difference of the measured third harmonic voltage ratio before and after the distributed phase regulator is connected to the grid exceeds the set threshold, the working condition adjustment control word is set to 1, otherwise, the working condition adjustment control word is set to 0;

[0117] Based on the working condition adjustment criterion, the K after the output fixed value is automatically switched Set value.

[0118] Preferably, the per-unit value acquisition unit 440 is specifically used to obtain the reactive power per-unit value based on the reactive power of the unit using the following formula:

[0119]

[0120] In the above formula, Q * is the reactive power per unit value, Q N is the rated capacity of the distributed phase-converter, and Q is the reactive power of the unit.

[0121] Preferably, the above-mentioned calculation constant determination unit 450 is specifically used to: form the following power adjustment criterion according to the reactive power per unit value, the third harmonic voltage ratio constant, the preset reliability coefficient and the preset power adjustment control word:

[0122]

[0123] In the above formula: K jsSet is the third harmonic voltage ratio calculation constant, kr is the reliability coefficient, k r The adjustable range is 0.01~0.2, the power adjustment control word is an adjustable control word, when the distributed phase regulator is a salient pole machine, the power adjustment control word is set to 1, when it is a hidden pole machine, the power adjustment control word is set to 0.

[0124] Preferably, the grounding protection judgment unit 460 is specifically used to: calculate the fixed value based on the third harmonic voltage ratio, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage to form a grounding protection criterion as shown in the following formula:

[0125]

[0126] In the above formula: is the third harmonic component of the zero-sequence voltage at the machine end, U n3 is the amplitude of the third harmonic component of the neutral point zero-sequence voltage; n TV3 is the PT transformation ratio of the neutral point zero-sequence voltage; n TV1 is the PT transformation ratio of the zero-sequence voltage at the machine end;

[0127] When the ground protection criterion meets the action conditions, after a delay T set , it is determined that the third harmonic zero-voltage stator grounding protection has been activated.

[0128] For a detailed description of the above-mentioned units and modules, please refer to the corresponding description in the aforementioned method embodiment, which will not be further elaborated here.

[0129] It can be seen from the above technical scheme that the third harmonic zero-voltage stator grounding protection device for distributed phase-shifting machines proposed in the present invention can quickly identify the operating conditions of the unit (before or after grid connection) through the operating condition adjustment criterion, and automatically switch the corresponding protection setting value, thereby avoiding misoperation or refusal of protection due to changes in operating conditions and improving the flexibility of protection. The power adjustment criterion further improves the protection reliability under different operating conditions through reactive power per unit braking. In addition, the present application is applicable to both salient-pole and non-salient-pole distributed phase-shifting machines, as well as various situations with organic-end circuit breakers and inorganic-end circuit breakers, and has a wide range of applications and is suitable for popularization and application.

[0130] Figure 6 is a schematic diagram of an electronic device provided by an embodiment of the present invention. Figure 6The electronic device shown is a general data processing device, which includes a general computer hardware structure, which includes at least a processor 801 and a memory 802. The processor 801 and the memory 802 are connected via a bus 803. The memory 802 is suitable for storing one or more instructions or programs executable by the processor 801. The one or more instructions or programs are executed by the processor 801 to implement the steps in the third harmonic zero-voltage stator grounding protection method of the distributed phase regulator.

[0131] The processor 801 may be an independent microprocessor or a collection of one or more microprocessors. Thus, the processor 801 executes the commands stored in the memory 802 to execute the method flow of the embodiment of the present invention as described above to realize the processing of data and the control of other devices. The bus 803 connects the above-mentioned multiple components together, and at the same time connects the above-mentioned components to the display controller 804 and the display device and the input / output (I / O) device 805. The input / output (I / O) device 805 may be a mouse, a keyboard, a modem, a network interface, a touch input device, a somatosensory input device, a printer, and other devices known in the art. Typically, the input / output (I / O) device 805 is connected to the system via an input / output (I / O) controller 806.

[0132] The memory 802 may store software components such as an operating system, a communication module, an interaction module, and an application program. Each of the modules and applications described above corresponds to a set of executable program instructions that implement one or more functions and methods described in the embodiments of the invention.

[0133] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the above-mentioned distributed phase-shifting phase third harmonic zero-voltage stator grounding protection method are implemented.

[0134] From the above, it can be seen that the third harmonic zero-voltage stator grounding protection method and device for distributed phase-shifting machine proposed in the present invention can quickly identify the operating conditions of the unit (before or after grid connection) through the operating condition adjustment criterion, and automatically switch the corresponding protection setting value, thereby avoiding the protection misoperation or refusal to operate due to changes in operating conditions, and improving the flexibility of protection. The power adjustment criterion further improves the protection reliability under different operating conditions through reactive power per unit value braking. In addition, the present application is applicable to both salient-pole and non-salient-pole distributed phase-shifting machines, as well as various situations with organic-end circuit breakers and inorganic-end circuit breakers. It has a wide range of applications and is suitable for promotion and application.

[0135] The preferred embodiments of the present invention are described above with reference to the accompanying drawings. Many features and advantages of these embodiments are clear from this detailed description, and therefore the claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. In addition, since many modifications and changes are easily conceivable to those skilled in the art, it is not intended to limit the embodiments of the present invention to the precise structure and operation illustrated and described, but all suitable modifications and equivalents falling within its scope may be covered.

[0136] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0137] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks 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 produce 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 1 A device that provides the functions specified in a block or multiple blocks.

[0138] 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 including 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.

[0139] 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.

[0140] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A distributed phase regulator third harmonic zero-voltage stator grounding protection method, characterized in that: The method comprises: Collect the closing position information of the circuit breaker at the machine end of the distributed phase modulator, the closing position information of the static reactive power compensator and the machine end analog quantity information; Based on the machine-side analog quantity information, the third harmonic component of the computer-side zero-sequence voltage and the neutral point zero-sequence voltage, the unit reactive power and the unit frequency; According to the closing position information of the machine-end circuit breaker, the closing position information of the static VAR compensator and the frequency of the unit, a working condition adjustment criterion is formed, and based on the working condition adjustment criterion, a third harmonic voltage ratio constant before and after grid connection is automatically switched; Obtaining a reactive power per unit value based on the reactive power of the unit; A power adjustment criterion is formed according to the reactive power per unit value, the third harmonic voltage ratio constant, a preset reliability coefficient and a preset power adjustment control word, and a third harmonic voltage ratio calculation constant is determined based on the power adjustment criterion; A grounding protection criterion is formed based on the calculated constant of the third harmonic voltage ratio, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, and based on the grounding protection criterion, it is determined whether the third harmonic zero-voltage stator grounding protection action conditions are met.

2. The distributed phase regulator third harmonic zero-voltage stator grounding protection method according to claim 1, characterized in that: The machine-end analog quantity information includes: sampling values ​​of the machine-end three-phase voltage, the machine-end three-phase current, the machine-end zero-sequence voltage and the neutral point zero-sequence voltage.

3. The distributed phase regulator third harmonic zero-voltage stator grounding protection method according to claim 2, characterized in that: The third harmonic component of the computer-side zero-sequence voltage and the neutral point zero-sequence voltage, the unit reactive power and the unit frequency based on the machine-side analog quantity information include: Using the sampling values ​​of the machine-end zero-sequence voltage and the neutral point zero-sequence voltage, the third harmonic component of the machine-end zero-sequence voltage and the third harmonic component of the neutral point zero-sequence voltage are calculated through Fourier algorithm and digital filter algorithm; The reactive power of the unit is obtained by using the sampling values ​​of the three-phase voltage and the three-phase current at the unit end through Fourier algorithm and reactive power algorithm; The unit frequency is obtained by using the sampling value of the three-phase voltage at the machine end through a hardware frequency measurement algorithm or a software frequency measurement algorithm.

4. The distributed phase regulator third harmonic zero-voltage stator grounding protection method according to claim 1, characterized in that: According to the closing position information of the machine-end circuit breaker, the closing position information of the static VAR compensator and the unit frequency, a working condition adjustment criterion is formed, and based on the working condition adjustment criterion, a third harmonic voltage ratio setting value before and after grid connection is automatically switched includes: When the closing position information of the machine-side circuit breaker is 1, the closing position information of the static reactive power compensator is 0, and the unit frequency is greater than the set frequency, the unit grid-connected state is determined to be 1. The closing position information of the machine-side circuit breaker is 1, indicating that the machine-side circuit breaker is closed, the closing position information of the static reactive power compensator is 0, indicating that there is no static reactive power compensator closing position, and the unit grid-connected state is 1, indicating that the unit is in the grid-connected state; When the closing position of the machine-side circuit breaker is 0 or the closing position of the static reactive power compensator is 1, the delay judgment is that the unit grid-connected state is 0. The closing position of the machine-side circuit breaker is 0, indicating that the closing position of the machine-side circuit breaker is not switched on. The closing position of the static reactive power compensator is 1, indicating that the closing position of the static reactive power compensator is switched on. The unit grid-connected state is 0, indicating that the unit is not in the grid-connected state. The following working condition adjustment criterion is constructed: In the above formula, K Set is the third harmonic voltage ratio constant, K BeforeSet K is the third harmonic voltage ratio constant before grid connection, AfterSet The third harmonic voltage ratio setting value after grid connection, the working condition adjustment control word is an adjustable control word. When the difference of the measured third harmonic voltage ratio before and after the distributed phase regulator is connected to the grid exceeds the set threshold, the working condition adjustment control word is set to 1, otherwise, the working condition adjustment control word is set to 0; Based on the working condition adjustment criterion, the K after the output fixed value is automatically switched Set value.

5. The distributed phase regulator third harmonic zero-voltage stator grounding protection method according to claim 1, characterized in that: The obtaining of a reactive power per unit value based on the reactive power of the unit comprises: Based on the reactive power of the unit, the reactive power per unit value is obtained using the following formula: In the above formula, Q * is the reactive power per unit value, Q N is the rated capacity of the distributed phase-shifting machine, and Q is the reactive power of the unit.

6. The distributed phase regulator third harmonic zero-voltage stator grounding protection method according to claim 5, characterized in that: The power adjustment criterion is formed according to the reactive power per unit value, the third harmonic voltage ratio constant, a preset reliability coefficient and a preset power adjustment control word, and the third harmonic voltage ratio calculation constant is determined based on the power adjustment criterion, including: According to the reactive power per unit value, the third harmonic voltage ratio constant, the preset reliability coefficient and the preset power adjustment control word, the following power adjustment criterion is formed: In the above formula: K jsSet is the third harmonic voltage ratio calculation constant, k r is the reliability coefficient, k r The adjustable range is 0.01~0.2, the power adjustment control word is an adjustable control word, when the distributed phase regulator is a salient pole machine, the power adjustment control word is set to 1, when it is a hidden pole machine, the power adjustment control word is set to 0.

7. The distributed phase regulator third harmonic zero-voltage stator grounding protection method according to claim 1, characterized in that: The grounding protection criterion is formed based on the third harmonic voltage ratio calculation constant, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, and judging whether the third harmonic zero-voltage stator grounding protection action condition is met based on the grounding protection criterion includes: Based on the calculated constant value of the third harmonic voltage ratio, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, a grounding protection criterion as shown in the following formula is formed: In the above formula: is the third harmonic component of the zero-sequence voltage at the machine end TV, U n3 is the amplitude of the third harmonic component of the neutral point zero-sequence voltage; n TV3 is the PT transformation ratio of the neutral point zero-sequence voltage; n TV1 is the PT transformation ratio of the zero-sequence voltage at the machine end; When the ground protection criterion meets the action conditions, after a delay T set , it is determined that the third harmonic zero-voltage stator grounding protection has been activated.

8. A distributed phase regulator third harmonic zero-voltage stator grounding protection device, characterized in that: The device comprises: An information collection unit is used to collect the closing position information of the circuit breaker at the machine end of the distributed phase modulator, the closing position information of the static reactive power compensator and the machine end analog quantity information; A data calculation unit, used for calculating the third harmonic component of the zero-sequence voltage at the computer end and the zero-sequence voltage at the neutral point, the reactive power of the unit and the frequency of the unit based on the analog quantity information at the machine end; A working condition adjustment unit, used for forming a working condition adjustment criterion according to the closing position information of the machine-end circuit breaker, the closing position information of the static VAR compensator and the unit frequency, and automatically switching the third harmonic voltage ratio constant before and after grid connection based on the working condition adjustment criterion; A per-unit value acquisition unit, used for obtaining a per-unit reactive power value based on the reactive power of the unit; A calculation constant determination unit, used to form a power adjustment criterion according to the reactive power per unit value, the third harmonic voltage ratio constant, a preset reliability coefficient and a preset power adjustment control word, and determine the third harmonic voltage ratio calculation constant based on the power adjustment criterion; The grounding protection judgment unit is used to form a grounding protection criterion based on the calculated constant of the third harmonic voltage ratio, the amplitude of the third harmonic component of the neutral point zero-sequence voltage, the PT transformation ratio of the neutral point zero-sequence voltage, and the PT transformation ratio of the machine-end zero-sequence voltage, and to judge whether the third harmonic zero-voltage stator grounding protection action condition is met based on the grounding protection criterion.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

Images