71results about How to "Suppression of subsynchronous oscillations" patented technology

The invention relates to a generating set sub-synchronous oscillation suppression method adopting a full-controlled variable current device. The method uses the variable quantity of a rotating speed signal of a generating set as a control quantity, and performs filter, phase shift, proportional amplification and operation processing on the variable quantity of the rotating speed signal to acquire a control signal for controlling a variable current power unit by using a voltage synchronization signal as standard, then the full-controlled variable current device generates a sub-synchronous model modulation current, and the current affects the rotating speed of the generating set through a power transmission unit so as to achieve the aim of suppressing the sub-synchronous oscillation of the generating set. A controller comprises a plurality of signal processing subunits and a main control subunit, wherein each signal processing subunit comprises a filter module, a phase shift module, a proportional amplification module and an operation module; and the main control subunit accomplishes the control for the full-controlled device. The method can effectively suppress the sub-synchronous oscillation problem of a power grid system, has high response speed and high tracing precision, and can greatly improve the stability and reliability of a power grid.

The invention discloses a device and method for suppressing subsynchronous oscillation of a power system. The method comprises the following steps of: firstly, filtering the rotation speed signal of a generator to obtain the subsynchronous rotation speed signal of each mode; processing the subsynchronous rotation speed signal of each mode respectively to obtain a change rate; then, generating an additional control signal through a Sugeno type fuzzy reasoning system; and finally, performing amplification, overlapping and amplitude limiting on the obtained additional control signal, and generating an exciting voltage additional control signal so as to change the exciting current, generate a subsynchronous frequency damping torque and suppress the subsynchronous oscillation. In the method provided by the invention, a training sample of a fuzzy controller is established according to the phase compensation principle, and the parameters of the fuzzy system are optimized and trained by use of a learning algorithm of an error backpropagation neural network. The method solves the problem that the expert experience is difficult to obtain by the fuzzy controller, and the additional exciting damping controller can effectively suppress the subsynchronous oscillation of the power system.

The invention discloses a supplementary subsynchronous damping control method of a speed regulator, belonging to the technical field of subsynchronous oscillation control of a power system. The method specifically comprises the following steps of: filtering, amplification, phase compensation, amplitude limiting and superposition. Power generator rotating speed deviation signals are used as input signals and the input signals are filtered to obtain subsynchronous rotating speed deviation signals of all modes; and amplification, phase compensation, amplitude limiting and superposition are conducted to the subsynchronous rotating speed deviation signals of all modes, amplitude limiting is conducted to the superposed signals to generate supplementary control signals delta Ugs of the speed regulator of a turbine generator set, and the supplementary control signals delta Ugs are connected with the output end of the speed regulator and are superposed with valve opening control signals output by the speed regulator, so as to regulate mechanical torque output by a turbine. By enhancing the mechanical damping of the shaft system of the generator set, subsynchronous oscillation caused by series compensation devices, direct current transmission devices and other devices can be effectively suppressed.

The invention provides a method and a device for suppressing subsynchronous oscillation of a double-fed wind power plant. The method comprises the following steps of acquiring a voltage signal and a current signal of an output end of the double-fed wind power plant; analyzing the voltage signal and the current signal, determining voltage amplitude, current amplitude and a subsynchronous oscillation frequency of the subsynchronous oscillation of the double-fed wind power plant; determining parameters of a damping controller according to the voltage amplitude, the current amplitude and the subsynchronous oscillation frequency of the subsynchronous oscillation and a damping controller parameter table, wherein the damping controller parameter table is a pre-established table for a corresponding relation between the oscillation frequency and the damping controller parameters; and connecting the damping controller with the determined control parameters to a reactive control link of a wind turbine generator of the double-fed wind power plant in series in order to suppress the subsynchronous oscillation of the double-fed wind power plant. According to the method and the device, the subsynchronous oscillation of the double-fed wind power plant is suppressed based on the parameter self-adjustable series type additional damping controller, and the subsynchronous oscillation of the wind power plant can be simply and quickly suppressed, so that a system can run stably.

The present invention relates to 300MW, 600MW, 1000MW steam turbine generator set shaft torsional vibration mode measurement and test method of large-scale thermal power plant, discloses a method of acting on generator excitation through excitation signal combined with dynamic continuous adjustment of excitation signal to obtain the best The closed-loop test of the optimal response realizes the detection method of the shafting torsional vibration mode of the online dynamic frequency sweeping unit. The dynamic online frequency sweeping method is used to output the modal characteristic excitation signal, which acts on the excitation system of the turbo-generator set and passes through the excitation system. The controllable electrical torque is generated in the turbogenerator set, and then the torsional vibration of the shafting of the unit is excited, and the torsional vibration intensity of the shafting is measured at the same time, so as to determine the natural mode of the shafting of the unit. This method can accurately measure the mechanical natural frequency of the shafting of the turbogenerator set, that is, the torsional vibration mode. Accurately testing the torsional vibration mode of the generator set is the basic research to solve the hazards of the subsynchronous oscillation of the unit, and is used to prevent, suppress and protect the generator set and Subsynchronous oscillation occurs in the power grid.

The invention relates to a measuring method of shaft torsional vibrations of 300MW, 600MW, 1000MW large turbogenerator unit of heat power generation, disclosing a method of self-adapting velocity-measuring tooth disc tooth number. The method firstly measures transient speed of the generator by perimeter measuring method, then processing secondary sampling with uniformly-face and fixed sampling frequency for the speed data via linear interpolation, further obtaining real-time speed data with equal space and fixed frequency sampling frequency irrelevant to tooth number of the generator, which reduces influence on trailing torsion calculation caused by inconsistency of tooth number of the velocity-measuring tooth disc. For the velocity tooth disc with different tooth numbers, sampling data with same sampling frequency and equal sampling space can be obtained measured by the method. The method unifies sampling rate of output data, reduces complexity level of processing link of trailing data, at the same time, guarantees reliability and precision of the data. The method is a basis for accomplishing measurement of shaft torsional vibrations, which is an important link for safe and stable operation of the generator unit.

The invention provides an anti-oscillating self-adaptive restraining system of subsynchronous oscillation of a large-size generator set. The anti-oscillating self-adaptive restraining system of the subsynchronous oscillation of the large-size generator set comprises a signal measurement control system and a static var compensator system, wherein the signal measurement control system is used for enabling measured torsional mode components of the large-size generator set to be through the processing of measurement, inverse amplification, lowpass filtering and self-adaptive control parameter generation in sequence to obtain a needed control signal and enabling the control signal to be input into the static var compensator system, the static var compensator system is used for controlling a triggering angle according to the control signal generated by the signal measurement control system so as to adjust equivalent admittance of the static var compensator system, then reactive power output by the static var compensator system is changed in a self-adaptive mode, corresponding damping torque is generated, and accordingly self-adaptive restraining of the subsynchronous oscillation of the large-size generator set is achieved. The anti-oscillating self-adaptive restraining system of the subsynchronous oscillation of the large-size generator set is capable of better restraining the occurrence of the subsynchronous oscillation of the large-size generator set.

The invention discloses a design method for an SVC (Static Var Compensators) controller based on improved atomic decomposition parameter identification. Based on an overcomplete damped sine atom library, a cosine migration model, a mixed migration operator and a mutation strategy are introduced to improve the biogeography optimization method, the improved biogeography optimization method is adopted to optimize the atom decomposition method, and the improved atom decomposition method is adopted to decompose a subsynchronous oscillation signal and identify a subsynchronous oscillation modal parameter; based on the identified subsynchronous oscillation modal parameter, an SVC subsynchronous damping controller is designed and optimized by the particle swarm algorithm. According to the invention, the subsynchronous oscillation modal parameter can be quickly and accurately identified, and the designed SVC subsynchronous damping controller has a favorable subsynchronous oscillation inhibition effect.

The invention discloses a double-fed wind turbine generator subsynchronous oscillation suppression method of a broadband rotor additional damping, which is implemented in control of a rotor-side converter of a doubly-fed fan and used for suppressing subsynchronous oscillation of a doubly-fed wind turbine generator; the three-phase currents of a double-fed fan rotator is detected; after the rotor current is detected, Park transform is performed on the three-phase currents to form a DQ axis system; filtering is performed by using a filter, sub-synchronous frequency band components of the rotor currents are extracted in real time, and then phase compensation and proportional amplification control is performed, the virtual additional rotor damping is added to an original converter DQ-axis rotor voltage control command. A control strategy of a fan rotor-side converter is changed to perform subsynchronous oscillation suppression, broadband additional damping control is increased on the rotor-side so as to enhance the damping characteristics of a subsynchronous frequency band of the wind turbine generator, the electrical damping of the whole wind turbine generator is enhanced, the subsynchronous oscillation of the system is suppressed; and the method can avoid additional devices, and is conductive to engineering implementation.

The invention discloses a method and system for suppressing the subsynchronous oscillation of a thermal power unit. The method comprises a step of establishing a suppression controller including a static var generator (SVC) and an supplementary excitation damping controller (SEDC). The two controllers have a sum relationship in the aspect of subsynchronous oscillation suppression. The SVC has a good suppression capability, and the SEDC has low investment. On the one hand, the combination of the two controllers can reduce the capacity of the SVC and reduce the investment. On the other hand, theSEDC can be used when the SVC is overhauled. The method and system can decrease, when the subsynchronous oscillation occurs, the oscillation amplitude and delay the generator tripping protection actuation time, so that workers can take more time to adjust the operation mode of the system to eliminate the subsynchronous oscillation of the unit.

The invention discloses a method for suppressing subsynchronous oscillation of a doubly-fed wind power plant based on a stator side analog resistor. The method comprises the following steps: firstly,establishing a system model of the doubly-fed wind power plant with series compensation capacitor grid connection; secondly, deducing an equivalent impedance model of the doubly-fed fan grid-connectedsystem in combination with a control strategy of a rotor side converter, and analyzing damping characteristics of the system; determining the value of a stator side analog resistor according to the analysis result of the damping characteristic of the doubly-fed fan grid-connected system so as to compensate the negative damping effect of the system; and finally, applying a control strategy based on the stator side analog resistor to control of a doubly-fed fan stator side converter, and completing suppression of subsynchronous oscillation of the system. The subsynchronous oscillation phenomenon in the wind power plant grid-connected system can be effectively inhibited, the stability of the system is improved, any additional device is not needed, the cost is saved, and the practical engineering application is facilitated.

The invention provides an SVG-based frequency closed-loop control method for dynamic suppression of sub-synchronous oscillation in a power grid. The control method comprises the steps of: collecting three-phase voltage of the power grid; tracking the three-phase voltage of the power grid to obtain a power grid frequency; filtering the power grid frequency to obtain an actual frequency value for suppression of sub-synchronous oscillation of the power grid; getting the difference between the actual frequency value for suppression of sub-synchronous oscillation of the power grid and a reference frequency value for suppression of sub-synchronous oscillation of the power grid so as to form a power grid frequency deviation value, and performing proportional integral control of the power grid frequency deviation value to obtain a control amount corresponding to the power grid frequency deviation value; conducting closed-loop control of the control amount corresponding to the power grid frequency deviation value to obtain a compensation voltage for suppression of sub-synchronous oscillation of the power grid, and suppressing sub-synchronous oscillation of the power grid. The control method of the invention can dynamically and effectively suppress sub-synchronous oscillation of the power grid.

The invention discloses a doubly-fed fan synchronous oscillation suppression method based on stator reactive hierarchical control. The method includes the steps of: S1. adopting a TLS-ESPRIT algorithm to identify and detect system subsynchronous oscillation; S2. when occurrence of subsynchronous oscillation of the system is detected, whether the decrease degree of subsynchronous oscillation in the system reaches a preset value is judged at short intervals [delta]t; S3. after reactive power transmitted by a doubly-fed fan stator is increased by one grade, judging whether inductive reactive power transmitted by the stator exceeds a limit of a reactive power regulation capability under a current wind speed state; S4. performing stator reactive hierarchical control, enabling the stator to increase transmitted reactive power by one grade, and returning to the Step S2 to continue to judge; and S5. ending a reactive hierarchical control strategy, and giving an alarm. The doubly-fed fan subsynchronous oscillation suppression method adopts hierarchical control, and can reduce influence of increase of transmitted reactive power on an original system as much as possible; and the method only needs to control a reactive power reference value of the doubly-fed fan stator, the control method is simple, and does not need to change a controller structure and increase extra investment equipment, and the control cost is low.

The invention discloses a sub-synchronous oscillation suppression method based on modal damping current injection, which belongs to the field of power system stabilization and control. The sub-synchronous oscillation suppression method comprises the steps that: sub-synchronous modal signals in a power generator rotation speed deviation signal and a voltage deviation value of a DC capacitor of a fully controlled type inverter are extracted, and sub-synchronous or super-synchronous damping current command signals for suppressing sub-synchronous oscillation as well as fundamental wave active current command signals for maintaining stability of a DC voltage of the fully controlled type inverter are acquired through a damping current control link and a DC voltage control link; an output current of the fully controlled type inverter tracks the current command signals through PWM control, and the output current is injected into a power generator set to generate electromagnetic torque of damping sub-synchronous oscillation, thereby achieving the purpose of suppressing sub-synchronous oscillation. The sub-synchronous oscillation suppression method based on modal damping current injection is fast in response speed, high in utilization rate of the output current of the inverter, can combine a plurality of sub-synchronous torsional oscillation modes, improves sub-synchronous stability of the system, and reduces torsional oscillation fatigue damages to a shaft system of a large-scale power generator.

The invention designs a method for suppressing sub-synchronous oscillation of a doubly-fed fan with an additional damping controller, which is applied to control of a rotor side converter of a doubly-fed fan. Parameters need to be configured firstly, then the additional damping controller is introduced into a rotor side converter controller of a doubly-fed fan, the additional damping controller is formed by cascading a band-pass filter, a first-stage gain amplifier and a second-stage gain amplifier, and the parameters of the two stages of amplifiers are determined according to a current inner loop proportionality coefficient of a rotor side converter control system. A rotor side current inner loop current error signal is the input of the damping controller, the output is superposed to an original inner loop output signal, and finally the effect of suppressing sub-synchronous oscillation is achieved. According to the method, extra sampling and measuring links do not need to be added, and the purpose of suppressing sub-synchronous oscillation occurring in a doubly-fed fan series compensation system can be achieved only by utilizing an existing control structure of a current inner loop and slightly improving the control structure.

The invention discloses a doubly-fed wind power plant subsynchronous oscillation suppression method capable of adaptively capturing frequency points, which comprises the following steps of: firstly, designing a subsynchronous oscillation additional damping ring; then, analyzing and tracking the oscillation frequency point at the grid-connected part of the target wind field by adopting real-time fast Fourier transform (FFT); performing self-adaptive adjustment of the additional damping ring based on the tracking frequency point; and finally, improving a rotor-side converter control strategy ofthe doubly-fed wind turbine generator by using the designed additional damping ring for adaptively capturing the frequency points. Compared with the same type of double-fed wind power plant subsynchronous oscillation suppression method, the method provided by the invention can accurately and effectively suppress the subsynchronous oscillation of the double-fed wind turbine generator, avoids the possible suppression effect weakening and overshoot caused by oscillation frequency point offset of the same type of method, and has important practical significance for the safe and stable operation ofthe double-fed wind turbine generator access system.

The invention provides a subsynchronous oscillation suppressing method and device for a wind generation set. The subsynchronous oscillation suppressing method includes: acquiring a stator current signal of a wind generation set in a synchronous rotation coordinate system, and calculating the subsynchronous oscillation frequency according to the stator current signal; querying and acquiring a phaseangle deviation ratio, a phase deviation time constant, and a proportionality coefficient which are corresponding to the subsynchronous oscillation frequency according to a phase angle deviation table, a proportionality coefficient table, and the subsynchronous oscillation frequency; generating a subsynchronous oscillation control signal according to the phase angle deviation ratio, the phase deviation time constant, the proportionality coefficient, and the stator current signal; and inputting the subsynchronous oscillation control signal to a basic network side control inner loop of the windgeneration set. In a special implementation aspect, an original detection and computing performance of a network side converter in a dual-fed set is utilized, subsynchronous oscillation is suppressedthrough a software control strategy upgrading, the cost of hardware loop reconstruction can be avoided, and engineering reconstruction is facilitated.

A direct-driven wind turbine generator subsynchronous oscillation suppression method capable of capturing frequency points in a self-adaptive mode comprises the steps of: firstly, designing a subsynchronous oscillation additional control loop; then, adopting real-time FFT analysis to track oscillation frequency points at the grid-connected part of the fan; performing self-adaptive adjustment of anadditional control loop based on the tracking frequency points; and finally, improving the phase-locked loop control strategy of the direct-driven wind turbine generator by applying the designed additional control loop of the self-adaptive capture frequency point, wherein compared with a current inner loop additional damping or the same type of subsynchronous oscillation suppression scheme, the direct-driven wind turbine generator subsynchronous oscillation suppression method can accurately and effectively suppress the subsynchronous oscillation of the direct-driven wind turbine generator, the suppression effect weakening and overshoot possibly caused by oscillation frequency point offset in an existing method are avoided, and the method has important practical significance for safe and stable operation of a direct-drive wind turbine generator access system.

The invention relates to a converter control-based doubly-fed induction generator sub-synchronous oscillation suppression method and belongs to the technical field of doubly-fed induction generators.With the converter control-based doubly-fed induction generator sub-synchronous oscillation suppression method adopted, sub-synchronous oscillation cannot be suppressed in the prior art can be solved.The method comprises the following steps that: when a doubly-fed induction generator grid-connected system undergoes synchronous oscillation, the operating data of the doubly-fed induction generatorgrid-connected system are acquired; a mapping relation between the dynamic energy variable quantities of induction generators and the control parameters of generator-side converters is obtained according to the response process of the doubly-fed induction generators under a power grid disturbance condition and a doubly-fed induction generator sub-synchronous oscillation divergence mechanism, so that the non-periodic change rate of the dynamic energy of the induction generators is obtained; a parameter optimization model is established with maximizing the non-periodic change rate adopted as anobjective, the inner ring control parameters of the generator-side converter of each induction generator in the doubly-fed induction generator grid-connected system are cooperatively optimized, and sub-synchronous oscillation is suppressed. With the converter control-based doubly-fed induction generator sub-synchronous oscillation suppression method of the invention adopted, the parameters of thedoubly-fed induction generators can be optimized and adjusted under a multi-constraint condition, and the generation of sub-synchronous oscillation can be effectively and effectively controlled.

The invention discloses a method for suppressing sub-synchronous oscillation of a wind power transmission system through series compensation by a superconducting magnetic energy storage and a controlsystem for suppressing sub-synchronous oscillation of a wind power transmission system through series compensation by a superconducting magnetic energy storage. The method comprises the steps of: thestep A, monitoring a bus power condition at the exit of a wind power plant in real time; the step B, if the control system determines the generation of sub-synchronous oscillation, starting an activeouter ring additional damping controller of a superconducting magnetic energy storage controller; the step C, observing the change state of the sub-synchronous oscillation, and if the convergence rateof the sub-synchronous oscillation does not reach a preset standard, starting a reactive outer ring additional damping controller of the superconducting magnetic energy storage controller; and the step D, when a sub-synchronous component of the power of the wind power plant in the system is smaller than an assigned value, quitting the outer ring additional damping controllers of the superconducting magnetic energy storage controller. Based on the sub-synchronous oscillation suppression method and the control system, on the basic function of the superconducting magnetic energy storage, the flexible and changeable operation conditions of the wind power plant can be adapted so as to effectively suppress the sub-synchronous oscillation of the wind power plant.

The invention relates to the technical field of parameter setting of subsynchronous oscillation damping controllers, and discloses parameter setting equipment and method for the subsynchronous oscillation damping controller. The subsynchronous oscillation damping controller comprises a modal filter and control equipment, wherein the modal filter is used for carrying out filtration on a rotating speed signal of a generator set to obtain a corresponding modal signal; the control equipment is connected with the modal filter and is used for achieving control on subsynchronous oscillation according to the modal signal; the control equipment comprises a compensation device; and the compensation device is connected between the modal filter and the control equipment, and is used for carrying out setting according to the filtered modal signal. The modal signal output by the modal filter is set through the compensation device which is connected with the modal filter in the subsynchronous oscillation damping controller in series; the accuracy of parameters in the subsynchronous oscillation damping controller is improved; and the subsynchronous oscillation damping controller can relatively well suppress subsynchronous oscillation, so that the generator set can be relatively well protected.

The invention discloses a method for suppressing subsynchronous oscillation of a doubly-fed wind power plant based on analog inductance. The method comprises the following steps: firstly, establishinga system model of the doubly-fed wind power plant with series compensation capacitor grid connection; then applying an analog inductance control strategy to the inner loop control of a doubly-fed fanrotor side controller to control the output voltage of the rotor; secondly, performing self-adaptive online setting on the analog inductance value by utilizing a PSO algorithm, and determining an optimal value of the analog inductance under a specific working condition; and finally, applying an analog inductance control strategy and a rotor side converter control strategy to the control of the rotor side of the doubly-fed fan, and completing the suppression of the subsynchronous oscillation of the system. The method improves the electrical damping in the subsynchronous frequency band, improves the stability of the system, and can meet the subsynchronous oscillation suppression requirements under multiple working conditions.

The invention discloses a method and device for optimizing subsynchronous oscillation of a synchronous machine based on an HVDC rectifier side converter. The method comprises the steps of obtaining three-phase AC voltage VABC of a converter bus of the HVDC rectifier side converter of an HVDC closed-loop control system, carrying out phase locking treatment and subsynchronous frequency conversion onthe three-phase AC voltage VABC to obtain to-be-damped subsynchronous oscillation modes and reserving the subsynchronous oscillation modes by using a band-pass filter; initiating subsynchronous oscillation through the HVDC closed-loop control system and then obtaining to-be-compensated phase angles of various subsynchronous oscillation modes according to a test signal method; and compensating a phase change caused by the HVDC closed-loop control system by using the phase angles and suppressing the subsynchronous oscillation initiated by the HVDC closed-loop control system. The suppression capability of a power system on the subsynchronous oscillation can be strengthened by using phase angle compensation, device upgrading and reconstruction of an existing converter are not needed, controlimplementation is simple and expansion is facilitated.

The invention provides a static var generator (SVG)-based given feedforward control method for dynamically inhibiting power grid subsynchronous oscillation. The control method comprises steps of collecting power grid three phase currents; converting the power grid three phase currents into an active current real value and a reactive current real value; filtering the active current real value and the reactive current real value, and carrying out negation to obtain an active current component and a reactive current component for inhibiting power grid subsynchronous oscillation; adding an active current given value in the active current component for inhibiting power grid subsynchronous oscillation to obtain a total active current given value, and adding a reactive current given value in the reactive current component for inhibiting power grid subsynchronous oscillation to obtain a total reactive current given value; and carrying out closed-loop control of the total active current given value and the total reactive current given value to obtain a compensation current for inhibiting power grid subsynchronous oscillation. Therefore, the power grid subsynchronous oscillation is inhibited. The control method can dynamically and effectively inhibit power grid subsynchronous oscillation.

The invention discloses a moving die test method by use of a restraint subsynchronous resonance (SSR) device, which comprises the following steps of: starting a frequency converter, generating a signal with the preset frequency by a signal generator, and adding the signal into a control device of the restraint SSR device so as to activate a generator to generate torsional vibration; measuring thephase difference between the signal generated by the signal generator and a feedback signal of a unit rotation speed so as to determine a correction parameter for phase correction; generating a subsynchronous signal by the frequency converter, and switching the restraint SSR device to a restraint state; superimposing a subsynchronous torque with the preset frequency in the output torque of the frequency converter, switching the restraint SSR device to a closed-loop restraint state, and monitoring the subsynchronous rotation speed signal with the preset frequency of the generator; if the subsynchronous rotation speed signal with the preset frequency of the generator is monitored and attenuates to the preset amplitude, finishing the step; and if the subsynchronous rotation speed signal doesnot attenuate to the preset amplitude, returning to the step d to adjust the correction parameter so that the subsynchronous rotation speed signal attenuates.

The invention discloses a DFIG subsynchronous oscillation suppression method based on a double-second-order generalized integrator, and belongs to the field of doubly-fed wind generator subsynchronousoscillation suppression. The problem that the stability of a power grid is affected due to the fact that subsynchronous oscillation of a DFIG unit of a wind power plant is induced when a series compensation capacitor is added into an existing long-distance power transmission line to improve the electric energy quality is solved. In the control process of the rotor converter, the subsynchronous harmonic component in the stator output voltage Vabc in the process of obtaining the phase theta1 by using the phase-locked loop is filtered by using the phase-locked loop realized by the second-order generalized integrator; a stator current sub-synchronous component suppression ring realized by a quasi-resonance controller is used for generating an estimated value of a sub-synchronous harmonic component in the DFIG rotor side rotor input voltage to counteract the harmonic component in a DFIG rotor side rotor input voltage instruction. The method is mainly used for suppressing the subsynchronousoscillation of the wind power generation system realized by the DFIG.

The invention relates to a multi-machine stabilization device and a multi-machine stabilization method for suppressing subsynchronous oscillation in a power system. The device comprises a speed measurement cabinet, a controller, a three-phase TCR and a step-down transformer which are connected to the conventional power grid and connected in turn. In the control method, the variation quantity of the rotation speed signals of a plurality of generator sets is used as control quantity, current flowing through the TCR is modulated by changing a thyristor conduction angle in the TCR system through controller operation, and finally the rotation speed of the generator is influenced so as to fulfill the aim of suppressing the subsynchronous oscillation. The device has the advantages of convenient control, simple structure, low cost and the like in the aspect of suppressing the subsynchronous oscillation; moreover, when the plurality of generator sets are arranged at the site, a signal processing unit can be expanded, and relevant components in other controllers are kept unchanged.

The invention provides a subsynchronous oscillation suppression method for a doubly-fed unit grid-connected system, and a related device. The method comprises the following steps: obtaining a subsynchronous component in a grid-connected current, and converting the subsynchronous component of the grid-connected current to a rotor side, thereby obtaining a rotor side subsynchronous component; and feeding back the subsynchronous component of the rotor side to a current regulator of the rotor side to control the rotor current. The subsynchronous component in the grid-connected current induces thesubsynchronous component on the rotor side, and the subsynchronous component of the grid-connected current is converted to the rotor side, so compared with the prior art, the method has the advantagesthat a group of inverted sub-synchronous components are superposed on the rotor side equivalently, and the inverted sub-synchronous components can induce a group of inverted sub-synchronous components on the stator side, so that the subsynchronous components of stator current on the rotor side are counteracted, the sub-synchronous components introduced by a grid-side converter can be suppressed,and the sub-synchronous oscillation of the doubly-fed unit grid-connected system is suppressed more effectively.