CN107579529B - Synchronous machine subsynchronous suppression method based on grid-connected converter phase-locked loop optimization - Google Patents
Synchronous machine subsynchronous suppression method based on grid-connected converter phase-locked loop optimization Download PDFInfo
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Abstract
The invention provides a synchronous generator subsynchronous suppression method based on grid-connected converter phase-locked loop optimization, which comprises the following steps: s1: collecting the electric semaphore of a grid-connected converter; s2: obtaining a synchronous rotation signal delta theta according to the electric semaphore of the grid-connected converter, carrying out band-pass filtering processing on the synchronous rotation signal delta theta, and judging whether the synchronous generator generates subsynchronous oscillation according to the processing result, if so, entering a step S3, and if not, keeping the bandwidth of a phase-locked loop of the grid-connected converter unchanged; s3: the damping of the alternating current system is improved by increasing the bandwidth of the phase-locked loop, and the improved damping is injected into the alternating current system to realize the suppression of subsynchronous oscillation. The method and the device have the advantages that the system capacity is not increased, meanwhile, the active and reactive power control branch is matched, the suppression effect of suppressing the subsynchronous oscillation of the synchronous generator is increased, and the capability of the existing subsynchronous oscillation suppression method in suppressing the subsynchronous oscillation is improved.
Description
Technical Field
The invention belongs to the field of power system stability control, and particularly relates to a synchronous generator subsynchronous suppression method based on grid-connected converter phase-locked loop optimization.
Background
The synchronous generator is one of the most important power supply equipment in the power system, the economic value is high, and the safe and stable operation of the synchronous generator plays an important role in the safe and stable operation of the power system. Subsynchronous oscillation of the synchronous generator belongs to system oscillation instability, along with gradual increase of the single-machine capacity of the turbonator synchronous generator, a shaft system of the generator becomes slender, the flexible characteristic of machinery is reflected by more characteristics of the shaft system, the special electromechanical coupling is more easily caused to be mutually used, the power generation equipment can be seriously damaged, and the safe and stable operation of a power system is threatened.
Dynamic analysis is carried out on the synchronous generator shafting, so that the synchronous generator shafting is in a stable state when the mechanical input torque and the electromagnetic damping torque are balanced. When the electromagnetic torque of the synchronous generator has non-fundamental frequency harmonic content, the synchronous generator can cause unbalance of a synchronous generator shaft system, when the unbalanced torque can not be effectively inhibited, the synchronous generator can cause various subsynchronous oscillation problems, when the oscillation frequency is the same as or close to the inherent oscillation frequency of the synchronous generator shaft system, the shaft system torsional oscillation problem of the synchronous generator can be excited, the shaft system of the synchronous generator can be damaged under severe conditions, and the safety and the stability of a power system are threatened. For example, in the last 70 th century, the oscillation damage accidents of the shafting of the steam turbine generator unit caused by the series compensation circuit continuously occur in the Mohave power plant in the United states, and the shafting torsional oscillation frequency is in the subsynchronous oscillation frequency range, so that the extensive research of people on the subsynchronous oscillation problem is caused.
The subsynchronous oscillation of the synchronous generator is inhibited mainly by researching the electrical damping characteristic of the synchronous generator and realizing the optimization of the electrical damping by some means to achieve the effect of inhibiting the subsynchronous oscillation of the synchronous generator. Factors influencing the electrical damping are more, such as the tide distribution of the system, a steady-state working point, an excitation control system, a stabilizer control system, an external grid structure of the synchronous generator, the impedance of the power transmission line, external other power electronic equipment and the like. The damping characteristics of the synchronous generator are difficult to accurately depict due to the complex power grid structure near the synchronous generator, and the influence and the severity of each device on the synchronous generator cannot be determined, so that a plurality of subsynchronous oscillation suppression means are needed to perform synergistic action on various devices, and the subsynchronous oscillation suppression of the synchronous generator is realized.
For the existing subsynchronous oscillation suppression method, the following measures are mainly adopted: firstly, the method comprises the following steps: for the mechanical discipline, the method can be realized by the optimized design of the synchronous generator shafting, avoids the inherent oscillation frequency of the subsynchronous frequency band, and can fundamentally realize the effective suppression of the torsional vibration of the synchronous generator shafting. Secondly, the method comprises the following steps: the method can be realized theoretically, but in actual engineering, lower harmonic components and some harmonic components are close to fundamental frequency, and effective filtering cannot be realized. Thirdly, the method comprises the following steps: the subsynchronous suppressors of the type have single functions, cannot expand other more functions and cannot adapt to the development of more complex power systems in the future. Fourthly: the power electronic device with the fully-controlled switching device is used for effectively inhibiting subsynchronous oscillation of the synchronous generator. By means of corresponding additional control algorithms and optimization of control parameters, effective suppression of full-band subsynchronous oscillation of the synchronous generator under different working conditions is achieved, and protection of the synchronous generator is achieved flexibly and effectively; meanwhile, according to the scheme, a special power electronic device can be added to a port of the synchronous generator, so that the reactive compensation of the synchronous generator can be realized in a normal state while subsynchronous oscillation is realized, and power electronic devices near the synchronous generator, such as new energy power generation, STATCOM reactive compensation, HVDC high-voltage direct-current transmission and the like, can be utilized, so that the economy and the effectiveness can be effectively improved.
The basic principle of realizing subsynchronous oscillation by using the scheme in the past is as follows: the reference value of a current control loop is generated after a synchronous generator rotating speed deviation signal is subjected to certain processing, subsynchronous frequency band current is injected into the unit, and certain electrical damping is generated on a synchronous generator rotor to achieve the purpose of inhibiting subsynchronous oscillation. The rotation speed signal of the synchronous generator is used as the input of the optimization control, the rotation speed acquisition of the synchronous generator is slow, and the rotation speed signal cannot reflect the subsynchronous oscillation of the system in time due to the inertia effect of each mass block of the synchronous generator, so that the subsynchronous oscillation inhibition effect is relatively delayed, the subsynchronous oscillation is relatively serious at the moment when the subsynchronous suppressor starts to act, and the performance of the suppressor is greatly reduced; meanwhile, a means of replacing rotating speed detection based on electrical measurement is adopted, the rotating speed signal of the synchronous generator is extracted through an electrical measurement signal and a corresponding digital controller algorithm, a reactive channel is used as a channel for subsynchronous suppression current, or an active and reactive channel is used as a channel for subsynchronous suppression current, the scheme can well achieve the effect of dynamic subsynchronous suppression, and certain requirements are required to be provided for the capacity of equipment or the capacity of a direct-current bus capacitor.
In summary, the existing method for subsynchronous oscillation of a synchronous generator has the following technical problems: the feedback error and the lag of the rotating speed of the synchronous generator are serious, and the synchronous generator cannot be timely and effectively put into a subsynchronous oscillation suppressor; by utilizing the optimal controller of the reactive control branch or the active and reactive control double branch, the effective suppression of the secondary synchronous oscillation of the synchronous generator under all working conditions is realized, the capacity of the device or the capacity of the direct-current bus capacitor needs to be correspondingly improved, and the cost and the volume are increased.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a synchronous generator subsynchronous oscillation suppression method based on grid-connected converter phase-locked loop optimization, which aims to increase the suppression effect of the subsynchronous oscillation of the synchronous generator by matching with an active and reactive control branch without increasing the system capacity and improve the capability of the existing subsynchronous oscillation suppression method in suppressing the subsynchronous oscillation; the method aims to solve the problem that in the prior art, the suppression effect of subsynchronous oscillation of the synchronous generator is poor due to serious rotating speed feedback error and delay of the synchronous generator.
The invention provides a synchronous generator subsynchronous suppression method based on grid-connected converter phase-locked loop optimization, which comprises the following steps of:
s1: collecting the electric semaphore of a grid-connected converter;
s2: obtaining a synchronous rotation signal delta theta according to the electric semaphore of the grid-connected converter, carrying out band-pass filtering processing on the synchronous rotation signal delta theta, and judging whether a synchronous generator generates subsynchronous oscillation according to the processing result, if so, entering step S3, and if not, keeping the bandwidth of a phase-locked loop of the grid-connected converter unchanged;
s3: the damping of the alternating current system is improved by increasing the bandwidth of the phase-locked loop, and the improved damping is injected into the alternating current system to realize the suppression of subsynchronous oscillation.
Further, in step S1, the grid-connected converter electrical semaphore includes a grid-connected converter PCC point three-phase alternating-current voltage VPCCThree-phase alternating current IPCCAnd DC side capacitor voltage Udc。
Further, in step S2, the three-phase ac voltage V is applied to the grid-connected inverterPCCAfter PARK conversion is carried out, three-phase alternating voltage active component u under a rotating coordinate system is obtaineddThe synchronous rotation signal delta theta is equal to the active power component u of the three-phase alternating voltage under the rotating coordinate systemd。
Further, in step S2, when the result after the band-pass filtering process is zero, the subsynchronous oscillation of the synchronous generator does not occur; and when the result after the band-pass filtering processing is not zero, the synchronous generator generates subsynchronous oscillation.
Further, in step S2, the synchronous rotation signal Δ θ is sequentially subjected to a bandpass filtering process and a gain amplification process to obtain a phase-locked loop bandwidth adjustment factor m.
Further, in step S3, the bandwidth of the phase-locked loop is increased according to the phase-locked loop bandwidth adjustment factor m to increase the damping of the ac system.
Furthermore, the cut-off frequency of the band-pass filter used in the band-pass filtering process is 5Hz-50 Hz.
Compared with the closest prior art, the invention has the beneficial effects that:
(1) the invention increases the inhibition capability of subsynchronous oscillation of the grid-connected converter only by changing the adjusting speed of the phase-locked loop controller of the grid-connected converter, and reduces the requirement on the capacity or devices of the grid-connected converter by matching with the original active and reactive control branch.
(2) The method can realize that the subsynchronous oscillation is started at the initial moment of disturbance of the synchronous rotation signal, has higher speed and more convenient operation compared with other suppression schemes of feedback through the rotation speed signal, and reduces the requirement on communication.
(3) The invention only needs to measure the electrical quantity of the voltage and the current of the PCC point of the grid-connected converter, realizes the synchronous rotation signal through the phase-locked loop controller, and has more mature and more accurate sampling on the prior digital sampling technology.
(4) The invention mainly increases subsynchronous damping according to the electric signal quantity of the grid-connected converter, can be conveniently expanded to other converters of the same type, does not need to upgrade and reform the existing converter, only needs to add optimized control of a phase-locked loop into the controller, and has simple control realization and convenient expansion.
Drawings
Fig. 1 is a flowchart of an implementation of a synchronous generator sub-synchronization suppression method based on grid-connected converter phase-locked loop optimization according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a synchronous generator subsynchronous suppression system based on grid-connected converter phase-locked loop optimization according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a phase-locked loop optimization controller according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
The invention provides a synchronous generator subsynchronous oscillation suppression method based on grid-connected converter phase-locked loop optimization, which is used for increasing the suppression effect of the subsynchronous oscillation of a synchronous generator by matching with an active reactive power control branch circuit without increasing the system capacity and improving the capability of the conventional subsynchronous oscillation suppression method in suppressing the subsynchronous oscillation.
Fig. 1 shows an implementation flow of a synchronous generator subsynchronous suppression method based on grid-connected converter phase-locked loop optimization according to an embodiment of the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown, and detailed descriptions are as follows:
the subsynchronous suppression method of the synchronous generator provided by the invention is applied to a grid-connected converter to realize the subsynchronous suppression method of the synchronous generator, and comprises the following steps:
step 1: three-phase alternating voltage V of PCC point of acquisition grid-connected converterPCCThree-phase alternating current IPCCCapacitor voltage U on the DC sidedc。
Step 2: for three-phase AC voltage VPCCPerforming PARK conversion to obtain three-phase AC voltage active component u under a rotating coordinate systemdAnd a voltage reactive component uq。
And step 3: three-phase alternating voltage active component u under rotating coordinate systemdApproximately equal to the synchronous rotation signal delta theta, which is passed through a phase-locked loop PI controller
And integral controller
Obtaining the phase angle theta of the voltage lock, i.e.
Wherein k ispAnd kiM is the bandwidth adjustment factor output by the optimization controller for the phase-locked loop PI controller parameter.
Further, step 3 comprises: the synchronous rotation signal delta theta is used as an input signal and sequentially passes through an optimization controller consisting of a band-pass filter and a gain amplifier, the obtained signal is a phase-locked loop bandwidth adjustment factor m for inhibiting subsynchronous oscillation, and the subsynchronous frequency band damping output by the alternating current side of the grid-connected converter is increased by increasing the bandwidth of the phase-locked loop controller, so that the subsynchronous frequency band oscillation of the synchronous generator in the alternating current system is inhibited, wherein the band-pass filter is designed between 5Hz and 50 Hz.
And 4, step 4: three-phase alternating current I of grid-connected converterPCCPerforming PARK conversion to obtain active component i of three-phase alternating current in a rotating coordinate systemdAnd a current reactive component iq。
And 5: the active outer ring of the main controller of the grid-connected converter can select constant direct current bus voltage control and constant active power control and output an active current instruction idref。
Further, step 5 specifically includes: when the direct current bus voltage is not stably controlled by other equipment, the active outer ring of the main controller of the grid-connected converter selects constant direct current voltage control to stabilize the direct current bus voltage and a direct current bus voltage reference value UdcrefWith measured value U of DC bus voltagedcDifferential, direct current voltage PI controller
Obtaining an active current command idref1I.e. by
Wherein k isp1And ki1As the parameter of the DC voltage PI controller, the reference value U of the DC bus voltagedcrefSet under per unit systemIs 1.
When other equipment is used for carrying out stable control on the voltage of the direct current bus, the active outer ring of the main controller of the grid-connected converter selects constant active power control, and the active power reference value PrefMaking difference with the actual value P of active power through an active power PI controller
Obtaining an active current command idref2I.e. by
Wherein k isp2And ki2For the active power PI controller parameter, the active power reference value PrefBetween (-1, 1) under per unit system, the actual value of active power P is equal to udid+uqiq。
Step 6: the reactive outer ring of the main controller of the grid-connected converter can select constant reactive power control and constant alternating voltage control to output a reactive current instruction value iqref。
Further, step 6 specifically includes: when the alternating voltage needs to be stably controlled by the grid-connected converter, the reactive outer ring of the main controller of the grid-connected converter selects the fixed alternating voltage to stabilize the voltage at the alternating side, and the amplitude reference value U of the alternating voltagerefMaking difference with actual value U of AC voltage amplitude value by AC voltage PI controller
Obtaining a reactive current instruction iqref1I.e. by
Wherein k isp3And ki3For AC voltage PI controller parameters, AC voltage reference UrefSetting the voltage value to be 1 under a per unit system, and enabling the actual value U of the alternating voltage to be equal to Ud。
When the alternating voltage does not need to be stably controlled by the grid-connected converter, the reactive outer ring of the main controller of the grid-connected converter selects constant reactive power control and a reactive power reference value QrefMaking difference with the actual value Q of the reactive power through a reactive power PI controller
Obtaining a reactive current instruction iqref2I.e. by
Wherein k isp4And ki4For reactive power PI controller parameters, reactive power reference QrefBetween (-1, 1) under per unit system, the absolute value is less than
Actual value of reactive power Q equal to uqid-udiq。
And 7: the active power instruction value i obtained in the step 5 is useddrefAnd the actual value i of the active component of the current obtained in the step 4dDifference, active current PI controller
Obtaining the active component E of the internal potential of the current converterdI.e. by
Wherein k isp5And ki5Is an active current PI controller parameter.
And 8: the reactive power instruction value i obtained in the step 6 is usedqrefAnd the actual value i of the reactive component of the current obtained in the step 4qDifference, channel reactive current PI controller
Obtain the reactive component E of the inner potential of the current converterqI.e. by
Wherein k isp6And ki6Is a reactive current PI controller parameter.
And step 9: for the active component E of the internal potential of the current converter in the steps 7 and 8dAnd is idleComponent EqCarrying out PARK inverse transformation to obtain a three-phase alternating current internal potential eabcAnd the PWM circuit is used for generating a PWM signal to drive the converter. Therefore, the electric system damping optimized and increased by the phase-locked loop controller in the step 3 is injected into the alternating current system, and the subsynchronous oscillation is restrained in the initial stage of the subsynchronous oscillation.
The invention relates to a synchronous generator subsynchronous suppression method based on grid-connected converter phase-locked loop optimization, in particular to a method for improving the damping characteristic of a grid-connected converter by utilizing a grid-connected converter PCC electrical signal and optimizing and controlling a phase-locked loop controller.
Compared with the scheme for suppressing the subsynchronous oscillation of the traditional system, the method only needs to measure the electric quantity of the voltage and the current of the PCC point of the grid-connected converter, realizes synchronous rotation signals through the phase-locked loop controller, and is more mature in the existing digital sampling technology and more accurate in sampling. The invention increases the inhibition capability of subsynchronous damping of the grid-connected converter only by changing the adjusting speed of the phase-locked loop controller of the grid-connected converter, and reduces the requirement on the capacity or devices of the grid-connected converter by matching with the original active and reactive control branch. The method can realize that the subsynchronous oscillation is started at the initial moment of disturbance of the synchronous rotation signal, has higher speed and more convenient operation compared with other suppression schemes of feedback through the rotation speed signal, and reduces the requirement on communication. The invention mainly increases subsynchronous damping according to the electric signal quantity of the grid-connected converter, can be conveniently expanded to other converters of the same type, does not need to upgrade and reform the existing converter, only needs to add optimized control of a phase-locked loop into the controller, and has simple control realization and convenient expansion.
In order to further explain the method for suppressing the sub-synchronization of the synchronous generator based on the optimization of the phase-locked loop of the grid-connected converter provided by the embodiment of the invention, the application of the method for suppressing the sub-synchronization of the synchronous generator based on the optimization of the phase-locked loop of the grid-connected converter provided by the invention is explained by taking a fixed direct-current voltage active outer loop controller and a fixed reactive power reactive outer loop controller as examples by combining with the accompanying drawings.
Fig. 2 is a schematic structural diagram of a synchronous generator subsynchronous suppression system based on grid-connected converter phase-locked loop optimization: 1 represents a grid-connected converter, which is equipment where the optimization controller is located and is connected to the low-voltage side of a main transformer; the device comprises a voltage measuring device 11, a synchronous rotation signal acquisition device and a phase locking angle acquisition device, wherein the voltage measuring device is used for measuring the voltage of a PCC (point of charge coupled device) of a port of a grid-connected converter and preparing for extracting the synchronous rotation signal and the phase locking angle; 12, a current measuring device for measuring the output current of the grid-connected converter; the topology 13 is a main circuit topology of the grid-connected converter, and the topology can be a two-level VSC converter or a multi-level voltage source type converter such as an MMC and the like; 2, a main transformer is used for connecting a grid-connected converter and a system side, a low-voltage side is connected with the grid-connected converter, and a high-voltage side is connected with an external system; 3, a grid-connected converter external system which contains power supply equipment such as a synchronous generator; 4 represents the device of the invention, the electric component of the port of the grid-connected converter is detected by the measuring devices 11 and 12, the voltage phase signal theta is obtained by the phase-locked loop controller 45, and the three-phase voltage signal is converted into the synchronous rotating coordinate system by the 41 and 42 coordinate converting devices, so as to obtain the voltage component u of the synchronous rotating coordinate systemd、uqConverting the three-phase current signals into a synchronous rotating coordinate system through 43 and 44 coordinate conversion devices to obtain a current component i in the synchronous rotating coordinate systemd、iq(ii) a Wherein, the phase-locked controller 45 is composed of a phase-locked PI controller 452, a phase-locked integral controller 451 and a phase-locked optimization controller 453, and the bandwidth of the phase-locked PI controller 452 is adjusted by the optimization controller 453 according to the synchronous rotation coordinate signal of the phase-locked loop, thereby realizing the improvement of the system damping of the grid-connected converter; and 5, a main control loop of the grid-connected converter is shown, wherein an active outer loop can select a fixed direct-current voltage controller and a fixed active power controller, the invention takes the fixed direct-current voltage controller as an example for illustration, a direct-current voltage measured value and a direct-current voltage reference value are passed through a PI controller 51 to obtain an inner loop active current controller reference value, a reactive outer loop controller can firstly select a fixed alternating-current voltage and a fixed reactive power controller, the invention takes the fixed reactive power controller as an example for illustration, a reactive power measured value and a reactive power reference value are passed through a PI controller 53 to obtain an inner loop reactive currentA controller reference value, a main controller inner ring current controller obtains a component E under an inner potential synchronous rotating coordinate system through PI controllers 52 and 54 according to the reference value and the actual value obtained by the outer ring controld、EqAnd obtains a three-phase alternating voltage signal e required for modulation through the coordinate inverse transformation controller 55abcAnd generates a switching signal for controlling the fully-controlled switching device through the PWM module 56, so that the apparatus outputs a desired current signal.
The specific implementation steps are as follows:
as shown in fig. 1 to 3, the method for suppressing the sub-synchronization of the synchronous generator based on the grid-connected converter phase-locked loop optimization mainly comprises the following steps:
s1: collecting the electric semaphore of a grid-connected converter;
the grid-connected converter output electrical semaphore comprises a PCC point voltage Vpcc and an output current Ipcc, wherein a voltage measuring device 11 can be used for measuring the PCC point voltage semaphore of the grid-connected converter, and a current measuring device 12 can be used for measuring the output current of the grid-connected converter.
S2: designing parameters of a phase-locked loop optimization controller of the grid-connected converter;
the electric signal quantity obtained in step S1 is processed by the first coordinate transformation unit 41 and the second coordinate transformation unit 42 to obtain Δ θ, the Δ θ is processed by the PI controller 452 and the integral controller 451 to obtain a PCC voltage phase angle θ, meanwhile, a phase-locked optimization controller is added to the classical phase lock, the Δ θ is processed by the phase-locked optimization controller to obtain a bandwidth adjustment factor m of a phase-locked loop controller, the ratio is applied to the phase-locked loop PI controller, and effective suppression of subsynchronous oscillation at the initial stage of subsynchronous oscillation of the system is realized by adjusting the damping characteristic of the system by the phase-locked loop.
S3: designing a main controller of the grid-connected converter;
the main control loop of the grid-connected converter is a module 5, wherein an active outer loop can select a fixed direct current voltage controller and a fixed active power controller, the invention takes the fixed direct current voltage controller as an example for illustration, a direct current voltage measured value and a direct current voltage reference value pass through a PI controller 51 to obtain an inner loop active current controller reference value, and the control loop has no module 5The power outer ring controller can select a constant alternating voltage controller and a constant reactive power controller, the invention takes the constant reactive power controller as an example for illustration, a reactive power measured value and a reactive power reference value pass through the PI controller 53 to obtain an inner ring reactive current controller reference value, the main controller inner ring current controller passes through the PI controllers 52 and 54 according to the reference value and the actual value obtained by the outer ring control, and obtains a component E under an inner potential synchronous rotating coordinate systemd、EqAnd obtains a three-phase alternating voltage signal e required for modulation through the coordinate inverse transformation controller 55abcAnd generates a switching signal for controlling the fully-controlled switching device through the PWM module 56, so that the apparatus outputs a desired current signal.
As shown in fig. 3, after Δ θ passes through the band pass filter, m is 1 if the output result of the band pass filter is zero, and m is increased in proportion to 1 if the output result of the band pass filter is not zero.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. A synchronous generator subsynchronous suppression method based on grid-connected converter phase-locked loop optimization is characterized by comprising the following steps:
s1: collecting the electric semaphore of a grid-connected converter;
s2: obtaining a synchronous rotation signal delta theta according to the electric semaphore of the grid-connected converter, carrying out band-pass filtering processing on the synchronous rotation signal delta theta, and judging whether a synchronous generator generates subsynchronous oscillation according to the processing result, if so, entering step S3, and if not, keeping the bandwidth of a phase-locked loop of the grid-connected converter unchanged;
s3: the damping of the alternating current system is improved by increasing the bandwidth of the phase-locked loop, and the improved damping is injected into the alternating current system to realize the suppression of subsynchronous oscillation.
2. The method for suppressing the subsynchronous synchronization of the synchronous generator according to claim 1, wherein in step S1, the grid-connected converter electrical semaphore comprises a grid-connected converter PCC point three-phase ac voltage VPCCThree-phase alternating current IPCCAnd DC side capacitor voltage Udc。
3. The method for suppressing the subsynchronous synchronization of a synchronous generator according to claim 1, wherein in step S2, the three-phase ac voltage V of the grid-connected converter is appliedPCCAfter PARK conversion is carried out, three-phase alternating voltage active component u under a rotating coordinate system is obtaineddThe synchronous rotation signal delta theta is equal to the active power component u of the three-phase alternating voltage under the rotating coordinate systemd。
4. The method for suppressing the subsynchronous oscillation of the synchronous generator according to claim 1, wherein in step S2, when the result of the band-pass filtering process is zero, the subsynchronous oscillation of the synchronous generator does not occur; and when the result after the band-pass filtering processing is not zero, the synchronous generator generates subsynchronous oscillation.
5. The method for suppressing the subsynchronous synchronization of a synchronous generator according to any of claims 1 to 4, wherein in step S2, the synchronous rotating signal Δ θ is sequentially subjected to a band-pass filtering process and a gain amplification process to obtain a phase-locked loop bandwidth adjustment factor m.
6. The method for suppressing the subsynchronous synchronization of the synchronous generators as claimed in claim 5, wherein in step S3, the bandwidth of the phase-locked loop is increased according to the bandwidth adjustment factor m of the phase-locked loop to increase the damping of the ac system.
7. The method for suppressing subsynchronous synchronization of a synchronous generator according to claim 5, wherein a band-pass filter used in the band-pass filtering process has a cutoff frequency of 5Hz to 50 Hz.
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| CN113013898B (en) * | 2021-03-17 | 2022-12-02 | 江苏国科智能电气有限公司 | Grid-connected inverter subsynchronous oscillation suppression method based on remote power grid phase locking |
| CN113162117B (en) * | 2021-05-12 | 2022-05-31 | 合肥工业大学 | Method for designing bandwidth of grid-connected inverter controller under weak grid |
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