101 results about "Subsynchronous resonance" patented technology

The invention discloses a subsynchronous damping control system for effectively inhibiting subsynchronous resonance and oscillation, belonging to the technical field of stableness and control of the electrical power systems. The system comprises a rotary speed checking pre-processor, a combined mode filter, a combined proportion phase shifter, a mode control signal synthesizer, a subsynchronous compensating current command calculator, a current beat controller and a DC / AC convertor. The invention inhibits shafting torsional vibration by injecting subsynchronous / supersynchronous current complementary with machine set shafting modal frequency, and can simultaneously inhibit multiple torsional vibration modals, so that the invention has comprehensive function, can solve the multi-modal subsynchronous resonance and oscillation problems of the electrical power system, improves the supersynchronous stability of the system and lowers shafting torsional vibration fatigue loss of a high-rating generator.

A wind turbine controlled to damp subsynchronous resonance oscillations on a grid is provided. The wind turbine includes rotor blades for turning by the wind, an electric generator rotatably coupled to the rotor blades, a power converter responsive to electricity generated by the electric generator, the power converter for converting the generated electricity to a frequency and voltage suitable for supply to the power grid, and the power converter for regulating voltage on the grid for damping the subsynchronous oscillations. Additionally, in one embodiment voltage regulation is supplemented by modulating real power to damp the subsynchronous oscillations.

The invention discloses a subsynchronous damping control system, and belongs to the power system stabilization and control technology field. The system includes a rotate speed testing and preposing processor, a combined mode filter, a combined proportion phase shifter, a mode control signal synthesizer and a nonlinear transformer. The system solves the problem of multimode subsynchronous resonance and oscillation of a power system, improves the subsynchronous stability of the power system, and reduces the shafting torsional oscillation fatigue loss of a large-size steam turbo generator.

The invention discloses a subsynchronous resonance TCSC (Thyristor Controlled Series Compensation) device of a transmission line inhibition system. The invention provides a controllable series compensation technology. A power transmission line is additionally provided with a controllable thyristor valve; a series condenser block and an inductor controlled by the thyristor valve are connected in parallel so as to form the TCSC device. The thyristor valve is a controllable element, so that the slide control over the total impedance of the TCSC device can be realized by virtue of controlling the conduction and the shutoff of a thyristor in the thyristor valve; and compared with fixed series compensation, the subsynchronous resonance of the system can be inhibited more effectively, the transmitting capacity and the transient stability of the system are improved, and the effects of reducing the linear reactance and improving the power distribution can be achieved.

The invention discloses a method and a device for suppressing subsynchronous resonance through a doubly-fed fan rotor side converter. The method comprises the steps as follows: a rotating speed signal and a subsynchronous resonance frequency of a wind generator rotor are obtained; an additional controller is determined according to the amplitude-frequency characteristics and the phase-frequency characteristics of the relationships of a rotating speed variation and an electromagnetic torque variation; the rotating speed signal is processed through the additional controller to obtain an additional controlled quantity; the additional controller comprises a band-stop filter module, a band-pass filter module and a phase-shift module; the additional controlled quantity is injected into the rotor side converter and is superposed to an original controlled quantity to generate an additional torque; and the phase difference between the additional torque and the rotating speed variation is within a range of 90-270 degrees, so that the target of suppressing the subsynchronous resonance in a doubly-fed fan series compensation transmission system is achieved.

The invention provides a flexible direct current additional subsynchronous oscillation control system for suppressing subsynchronous resonance and oscillation. The system comprises a feedback signal processor, a multi-mode band-pass filter, a multi-mode proportional phase shifter, a mode control signal synthesizer and an additional signal controller. A subsynchronous damping control strategy is added on a flexible direct current control system, a plurality of torsional vibration modes can be suppressed at the same time, functions are comprehensive, multi-mode subsynchronous resonance and oscillation of a power system can be achieved, subsynchronous stability of the system is improved, transmission capacity of a power grid is further improved, and safety of a generator is ensured.

A subsynchronous resonance suppression method for a doubly-fed wind turbine based on convertor cooperative damping control relates to the technical field of grid-connected control of doubly-fed wind turbines. The invention is to solve the problem that the subsynchronous oscillation suppression method has low device utilization rate and control errors. The invention comprises: sequentially performing Clark transform and Park transform on the collected stator current signal and the grid side converter current, and using a high-pass filter to eliminate the influence of the direct current component, inputting the d and q-axis disturbance components of the stator current into the proportional amplifier to obtain a rotor voltage additional signal, inputting the d and q-axis disturbance components of the grid side converter is input into the proportional amplifier to obtain a grid side converter current reference additional signal, loading the rotor voltage additional signal into the output signal of the rotor side current controller, and loading the grid side converter current reference additional signal into the input signal of the grid side converter current controller, thereby achieving the suppression of the subsynchronous resonance of the doubly-fed wind turbine.

The present invention relates to the coordinated control method of torsional stress relay in large thermal power plants' generators (300 MW and above), which will be adopted when shaft torsional oscillations occur. This invention also publishes a method of realizing selective trip the generators and the trip criterions which are implemented by the torsional stress relay and coordinated control master station (Tmaster). Tmaster will real-time monitor the operating status of the generators and TSR, TMaster will also real-time generate a trip priority level sequencing by analyzing the unit output.When generators occur subsynchronous resonance and shaft torsional oscillation, this method can ensure that TSR will trip some generators of the power plant according to the real-time generated trip strategy to inhibit the shaft torsional oscillation and safeguard the units. This method can also avoid the tremendous economic loss caused by tripping all the generators, and that will reduce the hazard to the transmission grid.

The present invention discloses an convergence RLC circuit model-based method for analyzing subsynchronous resonance in a power system. The method comprises the following steps of: establishing a power plant model and a series compensated transmission line system model so as to acquire a non-linear differential equation model of each subsystem; generating a state equation model according to a parameter under a particular working condition and the non-linear differential equation model; generating an algebraic equation model according to the Laplace transform and the state equation model; acquiring a final equivalent resistance model so as to acquire a series resonance point; aggregating the final equivalent resistance model into an equivalent second order RLC electric circuit model according to the series resonance point; and quantifying SSR analysis. According to the analysis method provided by an embodiment of the present invention, the final equivalent resistance model is aggregated into the equivalent second order RLC electric circuit model, so that the SSR analysis is quantified, thus implementing the accurate quantification evaluation of SSR, reducing analysis errors and improving analysis accuracy.

The invention provides a novel subsynchronous oscillation damping controller which adopts the structure that a capacitor is connected with an inverter in series or in parallel, or the controller is only formed by the inverter; according to the preset control policy of the inverter, the subsynchronous oscillation damping controller takes on the characteristics of the preset impedance to absorb, damp or bypass subsynchronous frequency component, thus increasing the electrical damping of the corresponding subsynchronous frequency and finally achieving the aim of inhibiting subsynchronous oscillation (SSO) or subsynchronous resonance (SSR) of an electric power system.

The invention discloses a wind power station subsynchronous resonance suppression method and system, the wind power station at least comprises: a plurality of wind turbines, a plurality of transformers and wind power station lines, the wind power station is characterized in that: acquiring voltage signals and current signals of wind power station lines, resistance and inductance of the plurality of wind turbines, resistance and inductance of the plurality of transformers, resistance and inductance of the wind power station lines and current signals actually outputted from the subsynchronous suppression system to a power grid; performing filtering processing on voltage signals and current signals of the wind power station lines, obtaining subsynchronous frequency signals, according to the subsynchronous frequency signals, the resistance and the inductance of the plurality of wind turbines, the resistance and the inductance of the plurality of transformers and the resistance and the inductance of the wind power station lines, obtaining wind power station closed loop transfer functions, and according to the current signals actually outputted from the subsynchronous suppression system to a power grid, optimizing the attenuation rate of the closed loop transfer functions under different zero points through optimizing parameters. According to the invention, the stability of the wind power station can be effectively improved.

The invention provides a method and a device for suppressing subsynchronous resonance of a double-fed induction generator-series compensation power transmission system. The method includes converting a subsynchronous frequency component under a stationary coordinate of current of the double-fed induction generator-series compensation power transmission system into a DQ coordinate subsynchronous frequency component; setting resonance frequency points of a proportional-integral resonant controller in a rotor-side current transformer of the system as the DQ coordinate subsynchronous frequency component to enhance control of a double-fed induction generator for the subsynchronous frequency component of the system so as to suppress the subsynchronous resonance of the system. The method and the device are capable of suppressing the subsynchronous resonance of the double-fed induction generator-series compensation power transmission system effectively.

The embodiment of the invention discloses a method and a system for realizing subsynchronous resonant control. By adoption of the method and the system, grid current control is realized by detecting a machine-end voltage signal of a generating set, extracting a subsynchronous resonance mode component from the machine-end voltage signal, generating the damping current reference quantity, superimposing the damping current reference quantity with an automatic generation control (AGC) power command, and outputting the damping current reference quantity superimposed with the AGC power command to converter equipment. Because the converter equipment can control and generate actual subsynchronous mode damping current to ensure that the damp of a system in subsynchronous resonance mode is positive, so that the influence on the stability of the generating set in the subsynchronous mode caused by the running of energy storage equipment is avoided, and the functions of improving the running stability of the energy storage equipment and an electric power system and effectively reducing the running risk of the generating set can be achieved.

The invention relates to a method for inhibiting the subsynchronous resonance of a wind power system. Based on a controlled series compensation method, a trigger delay angle of a controlled series compensation thyristor valve group is controlled and the current of a valve group reactor L is adjusted, so that controlled series compensation equivalent impedence is controlled, the equivalent impedence is corrected in a closed-loop control mode, and the trigger delay angle is corrected in real time. The method is characterized in that: by adopting a PSCAD / EMTDC software and MATLAB software joint operation mode and based on an MATLAB computing method and phase shift between capacitor voltage zero-crossing moment and synchronous turnover moment, an additional damping control algorithm is designed, the controlled series compensation real trigger delay angle is calculated and the subsynchronous resonance is inhibited.

The invention relates to a new type series compensated line subsynchronous resonance damping and short-circuit current limiting device adopting the switch transformer technology, and pertains to the technical field of power electronics, wherein the reliability and practicability of the circuit can be greatly improved by adopting the switch transformer technology. According to the device, the series capacitor compensation function can be realized when the power supply line is in normal conditions to improve the system transmission capacity; and the subsynchronous resonance damping function can be realized when the line is in subsynchronous resonance conditions, and the short-circuit current limiting function can be realized when the line is in short-circuit failure conditions to make the series compensated line electric transmission line operate stably and reliably.

The present invention discloses a parameter tuning approach for bypass damping filter to suppress subsynchronous resonance in power systems, namely determining the parameters of capacitor, inductor and damping resistor in BDF. Using this approach, the parameters of capacitor and inductor in BDF can be adjusted, so that the frequency where the negative electrical damping of generator reaches minimum can be away from the frequency range of low frequency oscillation mode and typical frequencies of each torsional mode; the parameter of damping resistor in BDF can be further adjusted so that the minimum value of negative electrical damping is in reasonable range. The application of BDF with parameters tuned by the present invention contributes to the suppression of both the torsional interaction effect and the transient torque amplification effect.

The invention provides a method and system for suppressing subsynchronous resonance of a compensated transmission system. The method includes: collecting rotor-side three-phase current Irabc, stator-side three-phase current Isabc and stator-side three-phase voltage Usabc of a grid-side converter of a double-feed fan of the compensated transmission system; subjecting Irabc, Usabc and Isabc to Clarke transmission to acquire rotor-side current Irabeta, stator-side current Isabeta and staor-side Usabeta under two-phase stationary coordinates; according to a rotor current reference value Irabeta<*> and Irabeta, acquiring a first feedforward control component; calculating a second feedforward control component according to equivalent reactance parameters, leakage coefficients and Irabeta of the rotator side; according to equivalent reactance parameters of the stator side, common reactance of the stator side and the rotor side and Isabeta and Usabeta, calculating flux control components of the stator side; according to the first feedforward control component, the second feedforward control component and flux control components, calculating control voltage Urabeta<*> of the rotor side; performing space vector modulation on Urabeta<*> to acquire switching control signals of the grid-side converter to suppress the subsynchronous resonance of the compensated transmission system.

The invention discloses a suppression method for subsynchronous resonance of an asynchronous wind power generator system by a UPFC (Unified Power Flow Controller). The suppression method is used for monitoring a current passing through the UPFC, the current is adjusted by a feedback stage to control corresponding reactive power, a voltage of a machine end is adjusted to a normal level, so that a certain damping torque is generated in a power generator, and the subsynchronous resonance is suppressed; and meanwhile, at a series connection side of the UPFC, the reactive power of a circuit is changed by changing a voltage of the series connection side, a reactive current in the asynchronous wind power generator system is affected by change of the reactive power of the circuit, a mechanical torque is considered to be constant in an electromagnetic transient condition, the rotational speed of a rotor of the asynchronous power generator is increased due to increase of an inductance current, the damping torque under a subsynchronous frequency is generated, and the subsynchronous resonance is suppressed. By the suppression method, the stability of a wind power plant system is improved, meanwhile, subsynchronous damping in the system can also be increased, and the subsynchronous resonance of the wind power generator can also be suppressed.

Provided is an analysis method and device of influence of direct drive fans on subsynchronous resonance of a power transmission system. The method comprises the steps of conducting equivalence on a series compensation power transmission system to obtain an equivalent parameters; building a simulation system according to single direct drive fan and a power transmission system equivalent model, obtaining a direct drive fan impedance characteristic of the direct drive fan in a subsynchronous frequency band through frequency scanning, and obtaining a double-fed fan impedance characteristic of a double-fed fan in the subsynchronous frequency band; performing calculating to obtain a mixed fan impedance characteristic after multiple double-fed fans and multiple direct drive fans are connected in parallel and a single fan impedance characteristic after the multiple double-fed fans are connected in parallel according to the direct drive fan impedance characteristic, the double-fed fan impedance characteristic and matching of the double-fed fans and the direct drive fans; judging subsynchronous resonance influence condition of the direct drive fans to the double-fed fan series compensation power transmission system under the matching by comparing the mixed fan impedance characteristic with single fan impedance characteristic. According to the analysis method and device of influence of the direct drive fans on the subsynchronous resonance of the power transmission system, subsynchronous resonance influence of the direct drive fans can be effectively analyzed.

The invention discloses characteristic value analysis model and step for the subsynchronous resonance analysis of a multi-machine power system, relating to the field of characteristic value analysis models of the subsynchronous resonance analysis of the power system. The deducing and calculating process of a method comprises the following step of: respectively writing a rotor motion equation of amultimass block model of a shaft system of a steam turbine generator, an electromagnetic transient state equation of a magnetic chain and the voltage of a generator, an electromagnetic transient state equation of a power transmission line, an electromagnetic transient state equation of a series-connected compensation capacitor and a control system equation of an excitation controller and the like. The invention obtains a differential equation set related to a state quantity by linearizing the equations on a stable-state operating point and can solve the characteristic value and the characteristic vector of a state equation coefficient matrix on the basis, obtain much information related to resonance damping characteristics by judging the stability of the subsynchronous resonance of the multi-machine power system and can be used for designing a controller to inhibit the subsynchronous resonance of the multi-machine power system by combining with a control theory.

The invention discloses a method for establishing a controllable serial compensation linearized model, which belongs to the technical field of electric system modeling. The method comprises the following steps of: forecasting the voltage value of a capacitor after a half power-frequency period by utilizing a Poincare mapping theory according to the current line current, the triggering angle and the capacitor voltage of a TCSC (Thyristor Controlled Series Capacitor), and then fitting a waveform curve of the capacitor voltage of the TCSC by using the data as sampling values, thereby obtaining a mathematical model for describing the dynamic properties of the TCSC. Because the data have a small sampling period, and each power-frequency period has two sampling points, the mathematical model is effective in the range of 0-50Hz and is suitable for analyzing the subsynchronous resonance process of a system with the TCSC in a characteristic analysis method. The mathematical model obtained by the invention can be matched with a system characteristic root equation.

The invention discloses a subsynchronous resonance electro-mechanical combination simulation method and system, wherein the method comprises the following steps that modeling parameters of an electric power system are obtained, and an electric model is built in PSCAD (power system computer aided design) software; modeling parameters of a steam turbine generator set shaft system are obtained, and a continuous mass block shaft system model is built in ANSYS software; a state file and a data file are set; a data communication interface is built; after starting signals are received, the combination simulation of the PSCAD software and the ANSYS software is realized through the electric model and the continuous mass block shaft system model. The method according to the embodiment of the invention has the advantages that through the combined calculation of the PSCAD software and the ANSYS software, the complicated mechanical shaft system is applied to time domain simulation analysis, so that the detailed torque change of each part of the shaft system can be directly obtained, and the foundation is laid for the subsequent fatigue analysis, more complete electro-mechanical coupling dynamic analysis is realized, and the analysis accuracy is improved.

The invention provides a blocking filtering method for inhibiting subsynchronous resonance of a series compensated transmission system of a doubly-fed wind power plant. The series compensated transmission system comprises a DFIG (Doubly-Fed Induction Generator) wind power plant and the series compensated transmission system connected with the DFIG wind power plant, wherein the wind power plant comprises induction motor, a power electronic converter and a power electronic converter control system; the method comprises the steps: selecting a blocking filter, wherein the blocking filter is used for filtering an SSR (subsynchronous resonance) modal signal in a control signal of the power electronic converter control system; analyzing a subsynchronous characteristic of the series compensated transmission system of the doubly-fed wind power plant and determining the characteristic frequency and bandwidth of the blocking filter; analyzing the structure of the power electronic converter control system so as to determine a plurality of embedded points therefrom; and embedding the blocking filter after parameters setting into at least one embedding point so as to filter the SSR modal signal in the control signal of the power electronic converter control system. The method provided by the invention can be used for effectively inhibiting subsynchronous resonance problem of the series compensated transmission system of the doubly-fed wind power plant.

The invention discloses a subsynchronous resonance or oscillation-oriented remote monitoring system, which comprises in-situ torsional vibration series devices, sub-station level data management centres and a main station level data management centre, wherein the in-situ torsional vibration series devices and the sub-station level data management centres are in communication connection through switches; the sub-station level data management centres and the main station level data management centre are in communication connection through power data networks; the torsional vibration series devices and a standard time system GPS are synchronous; the sub-station level data management centres finish integrating and forwarding of the data on all devices in a same power station; and the main station level data management centre finishes centralized management and comprehensive analysis of sub-station data within the jurisdiction. According to the subsynchronous resonance or oscillation-oriented remote monitoring system, intelligent clustering, risk assessment and safety pre-warning of a torsional vibration data-based machine-network operation mode are also achieved besides that real-time monitoring of subsynchronous resonance or oscillation characteristics in a regional power grid under ambient excitation can be achieved; and the subsynchronous resonance or oscillation-oriented remote monitoring system can effectively serve power dispatching operating personnel, and has the advantages of advanced technology, excellent performance, practicability, high expandability and the like.

The invention discloses a method for exciting subsynchronous oscillation of a generator set by utilizing a subsynchronous oscillation suppression device, which comprises the following steps of: connecting the output end of a signal generator with a rotating speed sampling end of a controller of the subsynchronous oscillation suppression device; generating a signal Asin(wt) by using the signal generator, wherein w=2*pi*f, f is preset frequency, and A is signal amplitude and equal to 0; increasing the signal amplitude of the signal generated by the signal generator, simultaneously detecting the vibration of the generator set by using the subsynchronous oscillation suppression device, and stopping increasing the signal amplitude when the vibration reaches the preset vibration amplitude; and recording vibration data. Through the method, accurate and controllable shafting torsional vibration can be generated in a multiple large turbine generator set system, working conditions of various sets in a power station are simulated when subsynchronous oscillation or subsynchronous resonance is generated in a power grid, and test environment and means are provided for setting parameters of devices and equipment for suppressing subsynchronous resonance and subsynchronous oscillation and protecting the shafting of the generator set in the power station.

The structure of the device is as follows. One end of the primary winding of the transformer through the cascaded compensation capacitance is connected to the transmission line of the first electric network; the other end of the primary winding of the transformer is connected to the transmission line of the second electric network. The resistance is connected to the two end of the primary winding or secondary winding of the transformer. The electric induction coil cascaded to the capacitance is parallel connected to the two ends of the secondary winding of the transformer. The invented device can restrain subsynchronous resonance on electric networks caused by series compensation and raise the compensating ratio to more than 90%. The invention increases transmission capacity, raises stability of entire electric networks as well as lowers the cost for operating equipment and electric networks.

The invention discloses a static synchronous compensator (STACOM) dual-channel-based method and device for suppressing subsynchronous resonance of a power grid. The method comprises the steps of obtaining a synchronous phase signal according to a three-phase end voltage signal; performing Park conversion on the three-phase end voltage signal and a three-phase current signal to obtain a corresponding direct-axis component and a corresponding quadrature-axis component; determining an active power current instruction 1 for maintaining stability of a DC voltage according to a DC voltage referencevalue and a DC bus voltage; obtaining an active power current instruction 2 and a reactive power current instruction according to a rotational speed difference signal of a synchronous motor; obtaininga direct-axis component and a quadrature-axis component of an output voltage according to the current instructions, the direct-axis component and the quadrature-axis component; performing vector synthesis on the synchronous phase signal to obtain a three-phase AC output voltage signal; and generating a switch signal of controlling a converter switch device. The maximum additive electrical impedance is provided under relatively small STATCOM capacity, and the fluctuation of the DC voltage is reduced.

An apparatus for reducing subsynchronous resonance phenomena in a power transmission system. A determining arrangement determines components of the voltage from stator windings of a generator with one or more discrete frequencies. A calculating arrangement calculates, on a basis of the result of the determining, a voltage to be added to the voltage from the stator windings for reducing phenomena in the power system and an arrangement adapted to add the voltage calculated to the voltage from the stator windings.

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 subsynchronous resonance risk quantitative evaluation method based on electrical damping at modal frequency, and belongs to the field of power system modeling and stability analysis. The method comprises the following steps: firstly, establishing a corresponding network space model for an actual thermal power generating unit connected to a complex power grid system, obtaining a corresponding network parameter matrix through the network space model, and establishing a state space equation of the whole system by simultaneous establishment of the network parameter matrixand a researched generating unit state space equation; calculating an electrical damping value at the natural torsional vibration modal frequency of the shafting of the generator set, comparing the electrical damping value with mechanical damping, judging whether subsynchronous resonance characteristics exist or not by judging whether the sum of the mechanical damping and the electrical damping is positive or negative, and realizing batch processing of subsynchronous resonance risk quantitative evaluation of the generator set accessed to a complex large power grid. The risk degree is observedmore comprehensively in combination with time domain simulation, repeated use of test signals for obtaining an electrical damping curve is avoided, and the workload and time are reduced.