101 results about "Subsynchronous resonance" patented technology

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 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 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 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 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 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 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 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.