Converter fault voltage ride-through simulation method and converter grid-connected power control strategy adjustment method
By establishing a grid-connected power control simulation model based on converter parameters and transformer parameters, the problem of fault voltage crossing of the converter under weak grid conditions is solved, and more stable grid-connected power control is achieved.
Patent Information
- Application Number
- CN202411665933.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-09-18
- Filing Date
- 2024-11-20
- Publication Date
- 2025-04-22
AI Technical Summary
Under weak grid conditions, the converter has large disturbance instability and serious overcurrent problems when the fault voltage passes through, resulting in the traditional grid-connected power control strategy no longer meeting the requirements.
By calculating the correspondence between the line resistance and the short-circuit ratio of the high-voltage side of the transformer, the correspondence between the line resistance and the short-circuit ratio of the high-voltage side of the transformer, and the correspondence between the line inductance and the short-circuit ratio, and then establishing the grid-connected power control simulation model of the converter.
The grid-connected power control simulation model is accurately constructed, which effectively reduces the repeated operations during the modeling process, and improves the fault voltage crossing capability of the converter under weak grid conditions and the stability of grid-connected power control.
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Figure CN119864856A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a converter fault voltage ride-through simulation method and a converter grid-connected power control strategy adjustment method, and belongs to the field of power electronic system modeling. Background Art
[0002] With the access of new power electronic equipment such as wind farms, photovoltaic power stations, and converters, the power system is gradually showing the "double high" characteristics of a high proportion of renewable energy and a high proportion of power electronic equipment. The short-circuit ratio at the public grid-connected point of the equipment is gradually reduced, and no longer meets the conditions of a strong power grid. Affected by the equivalent high inductive reactance value at the public grid-connected point, the equipment has problems such as large disturbance instability and severe overcurrent during weak grid voltage fault ride-through, resulting in the traditional grid-connected power control strategy no longer meeting the corresponding standard requirements.
[0003] At present, simulation models, interference stability analysis, control strategy debugging, etc. are mainly used to provide reference and guidance for the grid-connected converters in actual environments for the fault voltage ride-through problem of wind power, photovoltaic, energy storage and other equipment under weak power grids. Traditional simulation models ignore the excitation loss and excitation inductance of the transformer, the high and low side winding loss and winding leakage inductance, resulting in the mismatch between the short-circuit capacity at the public grid connection point and the parameters during simulation. At the same time, the parameter setting of the fault voltage ride-through simulation voltage divider impedance also ignores the influence of the transformer, resulting in the simulation model being unable to accurately achieve the specified low short-circuit ratio setting and fault no-load voltage coefficient setting. In addition, the setting of parameters in the modeling process is based on experience, and these parameters are often in a certain range, so it is necessary to fine-tune the corresponding parameters to meet the corresponding requirements. When the hardware circuit conditions change, the process needs to be repeated, which greatly increases the time cost. Summary of the invention
[0004] The purpose of the present invention is to provide a method for simulating fault voltage ride through of a converter and a method for adjusting a grid-connected power control strategy of a converter, so as to solve the problem that a large number of repeated operations are required to set parameters when simulating fault voltage ride through of a converter.
[0005] To achieve the above object, the solution of the present invention includes:
[0006] A method for simulating fault voltage ride-through of a converter of the present invention obtains a first corresponding relationship between the line resistance on the high-voltage side of the transformer and the short-circuit ratio and a second corresponding relationship between the line inductance on the high-voltage side of the transformer and the short-circuit ratio according to the corresponding relationship between the converter parameters, the transformer parameters and the short-circuit ratio of the common grid-connected point on the converter side; obtains the line resistance and the line inductance according to the actual short-circuit ratio of the simulation object and the first and second corresponding relationships; obtains the line impedance on the high-voltage side of the transformer according to the line resistance and the line inductance, and then obtains the fault voltage ride-through simulated voltage divider impedance on the high-voltage side of the transformer winding according to the line impedance; and establishes a grid-connected power control simulation model of the converter according to the line impedance and the fault voltage ride-through simulated voltage divider impedance.
[0007] Furthermore, the first corresponding relationship is:
[0008]
[0009] Among them, R1 is the transformer winding loss resistance, R m is the transformer excitation loss resistance, X m is the transformer excitation inductance reactance, R g is the line resistance on the high voltage side of the transformer, X g is the line inductance on the high-voltage side of the transformer, V1 is the rated line voltage on the high-voltage side of the transformer, S n is the rated capacity of the converter equipment, and SCR is the short-circuit ratio of the common grid-connected point on the converter side.
[0010] Furthermore, the second corresponding relationship is:
[0011]
[0012] Among them, X1 is the transformer winding leakage inductance, R m is the transformer excitation loss resistance, X m is the transformer excitation inductance reactance, R g is the line resistance on the high voltage side of the transformer, X g is the line inductance on the high-voltage side of the transformer, V1 is the rated line voltage on the high-voltage side of the transformer, S n is the rated capacity of the converter equipment, and SCR is the short-circuit ratio of the common grid-connected point on the converter side.
[0013] Furthermore, the line impedance is obtained according to the following formula:
[0014] Z g =R g +j100πL g
[0015] Among them, Z g is the line impedance, R g is the line resistance on the high voltage side of the transformer, Lg is the line inductance.
[0016] Furthermore, the fault voltage ride-through simulated voltage divider impedance value is obtained according to the following formula:
[0017]
[0018] Among them, Z f is the fault voltage crossing simulated voltage divider impedance, k is the fault voltage drop coefficient, Z m is the transformer excitation impedance, Z g is the line impedance.
[0019] A method for adjusting a grid-connected power control strategy of a converter, according to the corresponding relationship between the converter and transformer parameters and the short-circuit ratio of a common grid-connected point, respectively obtains a first corresponding relationship between the line resistance on the high-voltage side of the transformer and the short-circuit ratio and a second corresponding relationship between the line inductance on the high-voltage side of the transformer and the short-circuit ratio; according to the actual short-circuit ratio of a simulation object and the first and second corresponding relationships, respectively obtains the line resistance and the line inductance; according to the line resistance and the line inductance, obtains the line impedance on the high-voltage side of the transformer, and then obtains the fault voltage crossing simulated voltage divider impedance on the high-voltage side of the transformer winding according to the line impedance; establishes a grid-connected power control simulation model of the converter according to the line impedance and the fault voltage crossing simulated voltage divider impedance; uses the grid-connected power control simulation model to test a subsystem encapsulated with the grid-connected power control strategy of the converter, and adjusts the grid-connected power control strategy of the converter according to the test results.
[0020] Furthermore, grid-connected power control simulation models are established in the advanced digital power system simulator and the real-time digital simulator respectively, and the grid-connected power control strategy of the converter is tested in the advanced digital power system simulator and the real-time digital simulator respectively, and the control strategy is adjusted according to the difference in the test results.
[0021] Furthermore, the first corresponding relationship is:
[0022]
[0023] Among them, R1 is the transformer winding loss resistance, R m is the transformer excitation loss resistance, X m is the transformer excitation inductance reactance, R g is the line resistance on the high voltage side of the transformer, X g is the line inductance on the high-voltage side of the transformer, V1 is the rated line voltage on the high-voltage side of the transformer, S n is the rated capacity of the converter equipment, and SCR is the short-circuit ratio of the common grid-connected point on the converter side.
[0024] Furthermore, the second corresponding relationship is:
[0025]
[0026] Among them, X1 is the transformer winding leakage inductance, R m is the transformer excitation loss resistance, X m is the transformer excitation inductance reactance, R g is the line resistance on the high voltage side of the transformer, X g is the line inductance on the high-voltage side of the transformer, V1 is the rated line voltage on the high-voltage side of the transformer, S n is the rated capacity of the converter equipment, and SCR is the short-circuit ratio of the common grid-connected point on the converter side.
[0027] Furthermore, the fault voltage ride-through simulated voltage divider impedance value is obtained according to the following formula:
[0028]
[0029] Among them, Z f is the fault voltage crossing simulated voltage divider impedance, k is the fault voltage drop coefficient, Z m is the transformer excitation impedance, Z g is the line impedance.
[0030] The beneficial effects of the present invention are as follows: the present invention is a pioneering invention, and according to the correspondence between the converter parameters, the transformer parameters and the short-circuit ratio of the common grid-connected point on the converter side, the first correspondence between the line resistance on the high-voltage side of the transformer and the short-circuit ratio and the second correspondence between the line inductance on the high-voltage side of the transformer and the short-circuit ratio are obtained respectively; according to the actual short-circuit ratio of the simulation object and the first and second correspondences, the line resistance and the line inductance are obtained respectively; according to the line resistance and the line inductance, the line impedance on the high-voltage side of the transformer is obtained, and then the fault voltage crossing simulation voltage divider impedance on the high-voltage side of the transformer winding is obtained according to the line impedance, and the grid-connected power control simulation model of the converter is established according to the line impedance and the fault voltage crossing simulation voltage divider impedance. The present invention accurately constructs the grid-connected power control simulation model according to the corresponding relationship, and effectively reduces the repeated operations in the modeling process. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 It is the ADPSS simulation model of the weak grid-connected power control of the converter of the present invention;
[0032] Figure 2 It is a single-phase equivalent model of the normal working condition of the high-voltage side of the transformer in the embodiment of the present invention;
[0033] Figure 3 It is a single-phase equivalent model of the voltage fault drop condition on the high-voltage side of the transformer in the embodiment of the present invention;
[0034] Figure 4is a relationship curve between the actual measured value and the calculated set value of the short-circuit ratio of the converter side of the present invention;
[0035] Figure 5 is a relationship curve between the measured value of the no-load fault voltage drop of the converter of the present invention and the calculated set value;
[0036] Figure 6 It is a comparison waveform of the positive sequence voltage in ADPSS and RTDS simulation when a three-phase symmetrical low voltage 0% drop fault occurs under the condition of full power discharge power control of the converter of the present invention;
[0037] Figure 7 It is a comparison waveform of the positive sequence active power in ADPSS and RTDS simulation when a three-phase symmetrical low voltage 0% drop fault occurs under the full power discharge power control of the converter of the present invention;
[0038] Figure 8 It is a comparison waveform of positive sequence reactive power in ADPSS and RTDS simulation when a three-phase symmetrical low voltage 0% drop fault occurs under full power discharge power control of the converter of the present invention;
[0039] Fig. 9 It is a comparison waveform of the positive sequence active current in ADPSS and RTDS simulation when a three-phase symmetrical low voltage 0% drop fault occurs under the full power discharge power control of the converter of the present invention;
[0040] Fig.10 It is a comparison waveform of the positive sequence reactive current in ADPSS and RTDS simulation when a three-phase symmetrical low voltage 0% drop fault occurs under full power discharge power control of the converter of the present invention. DETAILED DESCRIPTION
[0041] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.
[0042] The idea of the present invention is to calculate the line impedance and the fault voltage ride-through simulation divider impedance according to the relationship between the transformer parameters, the converter parameters and the short-circuit ratio, so as to establish a grid-connected power control model of the converter under weak grid conditions and then accurately test the fault voltage ride-through capability of the converter under weak grid conditions.
[0043] Method Example 1:
[0044] This embodiment provides a method for simulating converter fault voltage ride-through. First, ADPSS (Advanced Digital Power System Simulator) and RTDS (Real Time Digital Simulator) are used to respectively establish a grid-connected control model of the converter under weak grid conditions. Figure 1 As shown, taking the grid-connected control model established by ADPSS as an example, the figure includes an ideal grid voltage source, line impedance, fault voltage ride-through simulation voltage divider impedance, transformer, converter, converter control subsystem, PWM modulation subsystem and power calculation subsystem. The ideal grid voltage source is a three-phase sinusoidal function voltage source with a line voltage effective value of 37KV, a voltage source frequency of 50Hz, and no internal resistance or inductance; the line impedance and fault voltage crossing simulation voltage divider impedance use series RLC elements; the transformer is a three-phase two-winding ordinary transformer, which is often used in engineering practice. When establishing the control model, the corresponding transformer can be selected according to the actual working conditions; the converter is modeled and simulated according to the converter power electronic equipment topology; the converter control subsystem, PWM modulation subsystem and power calculation subsystem encapsulate program codes for converter grid-connected power control; among them, the power calculation subsystem is used to calculate the converter's positive-sequence voltage per unit value, positive-sequence active power per unit value, positive-sequence reactive power per unit value, positive-sequence active current per unit value and positive-sequence reactive current per unit value; the converter control subsystem and PWM modulation subsystem output PWM waves according to the control strategy and modulation strategy respectively to achieve the function of controlling the converter's grid-connected power.
[0045] In the actual grid operation process, the short-circuit ratio of the converter at the public grid connection point determines whether the grid environment in which the converter actually operates at full power is a strong grid or a weak grid, thereby affecting the grid connection stability of the converter when facing voltage surges or drops.
[0046] Generally, the AC grid access end of the converter is used as the public grid connection point of the converter, that is, the connection line between the converter and the low-voltage side winding of the transformer is used as the public grid connection point, and the grid connection power control capability and fault voltage ride-through capability of the converter under the short-circuit ratio specified at the public grid connection point are examined. The parameters that affect the short-circuit ratio of the public grid connection point include the rated capacity of the converter, the effective value of the rated line voltage of the high- and low-voltage side windings of the transformer, the impedance of the grid line on the high-voltage side of the transformer, the excitation loss and excitation inductance of the transformer, and the winding loss and winding leakage inductance of the transformer.
[0047] The present invention is based on the circuit principle, and obtains the grid line impedance on the high-voltage side of the transformer according to the parameters of the converter and the transformer, and then derives the corresponding relationship between the line resistance and line inductance on the transformer side and the short-circuit ratio, and obtains the line resistance and line inductance on the transformer side according to the corresponding relationship and the short-circuit ratio under the actual working conditions, so as to obtain the size of the fault voltage crossing simulation divider impedance on the high-voltage side of the transformer winding, and then accurately constructs the fault voltage crossing model of the converter under weak grid conditions. The power calculation subsystem, the converter control subsystem and the PWM modulation subsystem are used to perform electromagnetic transient real-time simulation test and real-time simulation semi-physical simulation test on the model to ensure the consistency of the converter's weak grid operation simulation; and the grid-connected power control strategy of the converter is improved and optimized according to the different working conditions, providing guidance reference for the converter in the actual weak grid operation environment. Among them, the grid-connected power control strategy includes the converter control strategy and the PWM modulation strategy.
[0048] First, the transformer is circuit-equivalent when the fault voltage is simulated by the voltage-dividing impedance not working. The present invention takes phase A of the three phases as an example, and the equivalent circuit models of the other phases are consistent with phase A. The equivalent circuit model of phase A on the grid side of the transformer high-voltage side winding is as follows: Figure 2 As shown in the figure, R g With L g are the line resistance and line inductance on the high voltage side of the transformer respectively; R m With L m are the excitation loss and excitation inductance of the transformer respectively; R1 and L1, R2' and L2' are the high and low voltage side winding losses and winding leakage inductance of the transformer respectively. After impedance transformation, R1=R2', L1=L2'.
[0049] The relationship between the short-circuit ratio of the converter at the public grid-connected point on the low-voltage side of the transformer and the equivalent grid line impedance of the public grid-connected point is:
[0050]
[0051] Among them, Z L is the equivalent grid line impedance of the public grid connection point on the low-voltage side of the transformer, V2 is the effective value of the rated line voltage of the transformer low-voltage side winding, S n is the rated capacity of the converter equipment, SCR is the short-circuit ratio of the public grid-connected point, that is, the ratio of the short-circuit capacity at this point to the rated capacity of the converter, and the short-circuit capacity is the product of the open-circuit voltage and the short-circuit current at the public grid-connected point.
[0052] The line impedance at the public grid connection point on the low-voltage side of the transformer is equivalent to the high-voltage side of the transformer, which is:
[0053]
[0054] Among them, ZH is the equivalent impedance of the transformer high-voltage winding on the grid side, and V1 is the effective value of the rated line voltage of the transformer high-voltage winding.
[0055] According to formula (1) and formula (2), the equivalent impedance Z of the transformer high voltage winding grid side is obtained: H The size can be expressed as:
[0056]
[0057] Among them, Z 12 is the winding impedance of the transformer; Z m is the excitation impedance of the transformer; Z g is the line impedance on the high voltage side, which can be expressed as:
[0058] Z 12 =2(R1+j100πL1) (4)
[0059] Z m =R m +j100πL m (5)
[0060] Z g =R g +j100πL g (6)
[0061] The winding impedance and excitation impedance of the transformer are obtained from the no-load current per unit value, no-load loss, short-circuit impedance per unit value (short-circuit voltage percentage) and short-circuit loss parameters provided by the transformer manufacturer, which can be expressed as:
[0062]
[0063]
[0064] Among them, I nl is the per unit value of no-load current, P nl is the no-load loss, X 12 is the per unit short-circuit impedance, P sc is the short-circuit loss, S1 is the rated capacity of the transformer, L m_pu is the per unit value of transformer excitation inductance, R m_pu is the per unit value of transformer excitation resistance, L 1_pu is the per-unit value of transformer winding inductance, R 1_pu is the per unit value of transformer winding resistance.
[0065] If the relevant parameters of the transformer are unknown, it is necessary to conduct no-load tests and short-circuit tests on the transformer to actually obtain the no-load current per unit value, no-load loss, short-circuit impedance per unit value and short-circuit loss parameters: in the transformer no-load test, the high-voltage side is open-circuited and voltage is applied to the low-voltage side. When the open-circuit voltage on the high-voltage side reaches V1, the no-load current per unit value and no-load loss on the high-voltage side are measured. In the transformer short-circuit test, voltage is applied to the high-voltage side and the low-voltage side is short-circuited. When the short-circuit current on the high-voltage side reaches the rated phase current of the high-voltage side winding of the transformer, the short-circuit voltage percentage and short-circuit loss on the low-voltage side are measured.
[0066] According to formulas (3), (4), (5) and (6), the equivalent impedance of the grid side of the transformer high voltage winding can be expressed as follows:
[0067]
[0068] Among them, X1 is the transformer winding leakage inductance, X g is the inductive reactance of the transformer high voltage side line, X m is the inductive reactance of transformer excitation inductance.
[0069] Further sorting out formula (11) yields:
[0070]
[0071] According to formula (3) and formula (12), we get:
[0072]
[0073] According to formula (13), the relationship between the equivalent resistance and equivalent reactance of the high-voltage side circuit of the transformer winding and the short-circuit ratio of the common grid-connected point on the converter side can be obtained respectively:
[0074]
[0075] Among them, the left sides of the equal signs of formula (14) and formula (15) are the equivalent resistance and equivalent reactance of the high-voltage side circuit of the transformer winding, respectively.
[0076] At this time, according to formulas (7), (8), (9), (10), (14) and (15), the line resistance R on the high voltage side of the transformer is obtained respectively. g and line inductance L g The corresponding relationship between the short-circuit ratio and SCR.
[0077] Furthermore, according to the actual SCR under actual working conditions, the line resistance R is calculated. g and line inductance L g Then, combined with formula (6), the line impedance Z on the high-voltage side of the converter is calculated gSize, based on which the size of the simulated voltage-dividing impedance for the high-voltage side fault voltage crossing of the transformer winding is calculated. After connecting the simulated voltage-dividing impedance for the fault voltage crossing, the equivalent circuit model of phase A on the grid side of the high-voltage side winding of the transformer is as Figure 3 shown, where R f , L f , C f represent the resistance, inductance, and capacitance of the voltage-dividing impedance. According to this single-phase equivalent circuit model, the phase voltage V AN at no-load is calculated as follows:
[0078]
[0079] where, Z f is the simulated voltage-dividing impedance for the fault voltage crossing, and k is the multiple relationship between the voltage after the fault voltage dip stabilizes and the normal voltage when the converter is at no-load, that is, the fault voltage dip coefficient; k is selected with an appropriate value according to the actual working conditions.
[0080] Rearranging formula (16), the expression of Z f is obtained as follows:
[0081]
[0082] When 0 < k < 1, a fault low voltage crossing occurs. At this time, both the real part and the imaginary part of the expression of Z f calculated by formula (17) are positive. The resistance of the voltage-dividing impedance is the real part of Z f , the inductive reactance of the voltage-dividing impedance is the imaginary part of Z f , and the capacitance of the voltage-dividing impedance is infinite. When k > 1, a fault high voltage crossing occurs. At this time, both the real part and the imaginary part of the expression of Z f calculated by formula (17) are negative. The resistance of the voltage-dividing impedance takes the opposite of the real part of Z f , the inductance of the voltage-dividing impedance is 0, and the capacitive reactance of the voltage-dividing impedance is the imaginary part of Z f .
[0083] At this time, an accurate converter weak grid fault voltage ride-through model is constructed. In order to verify the beneficial effects of this scheme, this scheme is simulated and verified. Electromagnetic transient simulation tests are carried out based on the converter control subsystem that has encapsulated the converter control strategy and the PWM modulation subsystem of the PWM modulation strategy. Based on this, grid-connected full-power charging and discharging control and fault voltage ride-through simulation comparison tests under weak grid conditions are carried out, including ADPSS electromagnetic transient simulation tests and RTDS real-time simulation semi-physical simulation tests. The positive-sequence voltage per unit value, positive-sequence active power per unit value, positive-sequence reactive power per unit value, positive-sequence active current per unit value and positive-sequence reactive current per unit value of the converter under ADPSS and RTDS during the fault voltage ride-through period are compared respectively. Then, the control strategy and modulation strategy are improved and optimized according to the differences, so as to improve the stability of the converter's grid-connected power control under weak grid conditions.
[0084] Figure 4 It is the relationship curve between the actual value of the short-circuit ratio on the machine side of the converter (x) and the set value of the short-circuit ratio (y) calculated according to formula (14) and formula (15).
[0085] Figure 5 It is the relationship curve between the measured value (x) of the converter no-load fault voltage drop and the set value (y) of the no-load fault voltage drop calculated according to formula (17).
[0086] Figure 4 , Figure 5 It is proved that the converter machine-side short-circuit ratio modeling method and the converter fault voltage drop modeling method proposed in this scheme are basically consistent with the actual measurement results, and the relationship fitting curve is a straight line with high accuracy.
[0087] Figure 6 It is the comparison waveform of the positive sequence voltage in ADPSS electromagnetic transient and RTDS semi-physical simulation when a three-phase symmetrical low voltage 0% drop fault occurs under the condition of full power discharge power control of the converter.
[0088] Figure 7 It is the contrast waveform of positive sequence active power in ADPSS electromagnetic transient and RTDS semi-physical simulation when a three-phase symmetrical low voltage 0% drop fault occurs under full power discharge power control of the converter.
[0089] Figure 8 It is the contrast waveform of positive sequence reactive power in ADPSS electromagnetic transient and RTDS semi-physical simulation when a three-phase symmetrical low voltage 0% drop fault occurs under full power discharge power control of the converter.
[0090] Fig. 9It is the contrast waveform of positive sequence active current in ADPSS electromagnetic transient and RTDS semi-physical simulation when a three-phase symmetrical low voltage 0% drop fault occurs under full power discharge power control of the converter.
[0091] Fig.10 It is the contrast waveform of positive sequence reactive current in ADPSS electromagnetic transient and RTDS semi-physical simulation when a three-phase symmetrical low voltage 0% drop fault occurs under full power discharge power control of the converter.
[0092] Depend on Figure 6 , Figure 7 , Figure 8 , Fig. 9 , Fig.10 From the test results, it can be seen that the waveforms obtained when the electromagnetic transient simulation test and the real-time simulation semi-physical simulation test are carried out in this scheme are basically consistent.
[0093] Method Example 2:
[0094] The present embodiment provides a method for adjusting the grid-connected power control strategy of a converter. The simulation model used by the adjustment method when testing the control strategy of the converter is the grid-connected power control simulation model introduced in method embodiment 1, and the simulation platform and simulation process used by the adjustment method when testing the control strategy of the converter are also given in the converter fault voltage crossing simulation method in method embodiment 1. Since the introduction of the method is clear enough, it will not be repeated here.
[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A method for simulating converter fault voltage ride-through, characterized in that: According to the correspondence between the converter parameters, the transformer parameters and the short-circuit ratio of the common grid-connected point on the converter side, a first correspondence between the line resistance on the high-voltage side of the transformer and the short-circuit ratio and a second correspondence between the line inductance on the high-voltage side of the transformer and the short-circuit ratio are obtained respectively; According to the actual short-circuit ratio of the simulation object and the first and second corresponding relationships, the line resistance and line inductance are respectively obtained; according to the line resistance and line inductance, the line impedance on the high-voltage side of the transformer is obtained, and then according to the line impedance, the fault voltage crossing simulated voltage divider impedance on the high-voltage side of the transformer winding is obtained; according to the line impedance and the fault voltage crossing simulated voltage divider impedance, a grid-connected power control simulation model of the converter is established.
2. The converter fault voltage ride-through simulation method according to claim 1, characterized in that: The first corresponding relationship is: Among them, R1 is the transformer winding loss resistance, R m is the transformer excitation loss resistance, X m is the transformer excitation inductance reactance, R g is the line resistance on the high voltage side of the transformer, X g is the line inductance on the high-voltage side of the transformer, V1 is the rated line voltage on the high-voltage side of the transformer, S n is the rated capacity of the converter equipment, and SCR is the short-circuit ratio of the common grid-connected point on the converter side.
3. The converter fault voltage ride-through simulation method according to claim 1, characterized in that: The second corresponding relationship is: Among them, X1 is the transformer winding leakage inductance, R m is the transformer excitation loss resistance, X m is the transformer excitation inductance reactance, R g is the line resistance on the high voltage side of the transformer, X g is the line inductance on the high-voltage side of the transformer, V1 is the rated line voltage on the high-voltage side of the transformer, S n is the rated capacity of the converter equipment, and SCR is the short-circuit ratio of the common grid-connected point on the converter side.
4. The converter fault voltage ride-through simulation method according to claim 1, characterized in that: The line impedance is obtained according to the following formula: Z g =R g +j100πL g Among them, Z g is the line impedance, R g is the line resistance on the high voltage side of the transformer, L g is the line inductance.
5. The converter fault voltage ride-through simulation method according to claim 1, characterized in that: The fault voltage ride-through simulated voltage divider impedance value is obtained according to the following formula: Among them, Z f is the fault voltage crossing simulated voltage divider impedance, k is the fault voltage drop coefficient, Z m is the transformer excitation impedance, Z g is the line impedance.
6. A method for adjusting a converter grid-connected power control strategy, characterized in that: According to the correspondence between the parameters of the converter and transformer and the short-circuit ratio of the common grid-connected point, a first correspondence between the line resistance on the high-voltage side of the transformer and the short-circuit ratio and a second correspondence between the line inductance on the high-voltage side of the transformer and the short-circuit ratio are obtained respectively; according to the actual short-circuit ratio of the simulation object and the first and second correspondences, the line resistance and line inductance are obtained respectively; according to the line resistance and line inductance, the line impedance on the high-voltage side of the transformer is obtained, and then the fault voltage crossing simulated voltage divider impedance on the high-voltage side of the transformer winding is obtained according to the line impedance, and a grid-connected power control simulation model of the converter is established according to the line impedance and the fault voltage crossing simulated voltage divider impedance; the subsystem encapsulated with the converter grid-connected power control strategy is tested using the grid-connected power control simulation model, and the converter grid-connected power control strategy is adjusted according to the test results.
7. The method for adjusting the converter grid-connected power control strategy according to claim 6, characterized in that: The grid-connected power control simulation model is established in an advanced digital power system simulator and a real-time digital simulator respectively, and the grid-connected power control strategy of the converter is tested in the advanced digital power system simulator and the real-time digital simulator respectively, and the control strategy is adjusted according to the difference in the test results.
8. The method for adjusting the converter grid-connected power control strategy according to claim 6, characterized in that: The first corresponding relationship is: Among them, R1 is the transformer winding loss resistance, R m is the transformer excitation loss resistance, X m is the transformer excitation inductance reactance, R g is the line resistance on the high voltage side of the transformer, X g is the line inductance on the high-voltage side of the transformer, V1 is the rated line voltage on the high-voltage side of the transformer, S n is the rated capacity of the converter equipment, and SCR is the short-circuit ratio of the common grid-connected point on the converter side.
9. The method for adjusting the converter grid-connected power control strategy according to claim 6, characterized in that: The second corresponding relationship is: Among them, X1 is the transformer winding leakage inductance, R m is the transformer excitation loss resistance, X m is the transformer excitation inductance reactance, R g is the line resistance on the high voltage side of the transformer, X g is the line inductance on the high-voltage side of the transformer, V1 is the rated line voltage on the high-voltage side of the transformer, S n is the rated capacity of the converter equipment, and SCR is the short-circuit ratio of the common grid-connected point on the converter side.
10. The method for adjusting the converter grid-connected power control strategy according to claim 6, characterized in that: The fault voltage ride-through simulated voltage divider impedance value is obtained according to the following formula: Among them, Z f is the fault voltage crossing simulated voltage divider impedance, k is the fault voltage drop coefficient, Z m is the transformer excitation impedance, Z g is the line impedance.