A damping control method and system for suppressing low frequency oscillations and subsynchronous oscillations

Abstract

A damping control method and system for inhibiting low-frequency oscillation and subsynchronous oscillation. The technical scheme provided by the present application comprises: calculating a unit value of a high-pressure cylinder rotor speed deviation, a unit value of a power deviation and a unit value of a generator speed deviation according to unit operation parameters; performing subsynchronous oscillation inhibition processing on the unit value of the high-pressure cylinder rotor speed deviation and the unit value of the generator speed deviation to obtain a subsynchronous oscillation control signal; performing low-frequency oscillation inhibition processing on the unit value of the high-pressure cylinder rotor speed deviation and the unit value of the power deviation to obtain a low-frequency oscillation control signal; and inputting the subsynchronous oscillation inhibition signal and the low-frequency oscillation inhibition signal into an excitation control system to comprehensively inhibit low-frequency oscillation and subsynchronous oscillation. The problem that low-frequency oscillation and subsynchronous oscillation are often independently designed and implemented by relying on different control devices and lack coordination between different controls is effectively solved, and the super low-frequency oscillation mode is considered, so the range of action is comprehensive.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system operation control, and in particular relates to a damping control method and system for suppressing low-frequency oscillation and subsynchronous oscillation. Background Art

[0002] Low-frequency oscillations in power systems generally refer to active power fluctuations with frequencies between 0.2 and 2.5 Hz. Based on the oscillation mechanism and frequency, low-frequency oscillations are further categorized as inter-regional and intra-regional. Inter-regional oscillations occur between 0.2 and 0.7 Hz and are characterized by fluctuations between groups of generators in different regions. Intra-regional oscillations, also known as local oscillations, occur between 0.7 and 2.5 Hz and are characterized by fluctuations between different generators within a region. With the continued expansion of national power grid interconnection, ultra-low-frequency oscillations of around 0.1 Hz have also emerged. The document “Analysis and Simulation of the Mechanism of Ultra-Low Frequency Oscillation in Yunnan Power Grid under Asynchronous Interconnection” (China Southern Power Grid Technology, 2016, 10(7): 29-34) points out that in 2016, when Yunnan Power Grid and Southern Main Grid implemented asynchronous interconnection system tests and carried out preset DC power boost and other test projects, it was found that Yunnan Power Grid had a long period of ultra-low frequency oscillation (about 0.05Hz). Through the analysis of a large amount of field test data, it was locked that the hydropower unit speed control system was the direct cause of the oscillation, and the mechanism of the hydropower unit speed control system providing negative damping during the oscillation process was analyzed.

[0003] Subsynchronous oscillations in power systems generally refer to active power fluctuations with frequencies between 10 and 40 Hz. Based on the dominant source of the oscillation mode, existing technical literature divides subsynchronous oscillations into three major types. The first type originates from the shaft torsional vibration of rotating electrical machines, including large steam turbines, hydro turbines, type 1-3 wind turbines, and large electric motors. The series capacitors, high-speed control equipment / devices (including SVC, LCC-HVDC, VSC-HVDC, PSS / electro-hydraulic speed regulation), and switches in the system that perform switching operations react to mechanical torsional vibrations, potentially weakening or even turning negative the damping torque of the unit in the corresponding torsional vibration mode, causing the oscillation to persist or even amplify. The second form originates from electrical oscillations caused by the inductance (L) and capacitance (C) in the power grid. Circuit elements that form LC oscillations exist in AC series-compensated power grids, various filter circuits, and parallel compensation. From the perspective of the power grid alone, the positive resistance characteristics of network elements will not cause the LC oscillations to persist or diverge. However, rotating electrical machines (including synchronous / asynchronous generators / motors) or power electronic converters may exhibit an "induction generator / negative resistance" effect on this oscillation mode under certain operating conditions. When the negative resistance exceeds the total positive resistance of the power grid, it may cause the LC oscillation to diverge. Of course, the motor or converter will also change the equivalent inductance / capacitance parameters, thereby changing the oscillation frequency to a certain extent. The third type of oscillation arises from machine-grid coupling oscillations caused by interactions between power electronic converters or between them and the AC grid. Unlike types 1 and 2, this type of oscillation is often difficult to identify from the generator or grid side. Based on an impedance model, it can be viewed as a phenomenon in which the "virtual impedance" formed by multiple converters and the grid exhibits series (imaginary impedance part not equal to zero, real part less than or equal to zero) or parallel (infinite impedance) resonance at specific frequencies. In actual systems, all three types of oscillation can coexist.

[0004] Different suppression methods and measures have been proposed both domestically and internationally for the various oscillation modes mentioned above. For low-frequency oscillations, the power system stabilizer (PSS) proposed by foreign scholars is commonly used. For ultra-low-frequency oscillations, PSS or proportional-differential (PD) controllers can be used. For subsynchronous oscillations, a bandpass filter in series with a lead-lag link can also be used based on the phase compensation principle. Suppression / controllers for low-frequency and subsynchronous oscillations are often designed independently and implemented using different control devices, resulting in high investment costs and a lack of coordination between different control devices.

[0005] There are two main problems in the research on the simultaneous suppression of low-frequency oscillations and subsynchronous oscillations: (1) the comprehensive suppression of ultra-low frequency oscillation modes (<0.2Hz) is not considered; (2) the integrated controller of low-frequency oscillations and subsynchronous oscillations relies on the HVDC transmission system and STATCOM (SVG). The operation reliability of the HVDC transmission system is high, and the additional modulation function of oscillation suppression is generally rarely considered in actual operation; the capacity of STATCOM (SVG) is limited and the cost is high, which limits its oscillation suppression ability and its promotion and application. Summary of the Invention

[0006] In order to solve the above-mentioned deficiencies in the prior art, the present invention provides a damping control method and system for suppressing low-frequency oscillation and subsynchronous oscillation.

[0007] The technical solution provided by the present invention is:

[0008] A damping control method for suppressing low-frequency oscillation and subsynchronous oscillation, comprising:

[0009] The per-unit value ΔW of the high-pressure cylinder rotor speed deviation is calculated based on the unit operating parameters h、 Per-unit value of power deviation ΔP e and the per-unit value of the generator speed deviation ΔW g ;

[0010] The per-unit value ΔW of the high-pressure cylinder rotor speed deviation h and the per-unit value of the generator speed deviation ΔW g Perform subsynchronous oscillation suppression processing to obtain the subsynchronous oscillation control signal U sso ;

[0011] The per-unit value ΔW of the high-pressure cylinder rotor speed deviation h And the per-unit value of power deviation ΔP e Perform low-frequency oscillation suppression processing to obtain a low-frequency oscillation control signal U pss ;

[0012] The subsynchronous oscillation suppression signal U sso and the low frequency oscillation suppression signal U pss Comprehensively suppress low-frequency oscillation and subsynchronous oscillation through the excitation control system;

[0013] The unit operating parameters include: a high-pressure cylinder rotor speed reference value and a measured high-pressure cylinder rotor speed value, an active power reference value and a measured active power value, and a generator rotor speed reference value and a measured generator rotor speed value.

[0014] Preferably, the per-unit value ΔW of the high-pressure cylinder rotor speed deviation is hand the per-unit value of the generator speed deviation ΔW g Subsynchronous oscillation suppression processing is performed to obtain a subsynchronous oscillation control signal U sso ,include:

[0015] The per-unit value ΔW of the generator speed deviation g and the per-unit value ΔW of the high-pressure cylinder rotor speed deviation h The first pre-processing link is input and a weighted combination algorithm is used to construct a comprehensive feedback signal as a weighted combined speed signal;

[0016] The weighted combined speed signal passes through a bandpass filter, then enters the phase shift compensation link, and finally enters the proportional amplification and limiting link to obtain the subsynchronous oscillation suppression signal U sso .

[0017] Preferably, the per-unit value ΔW of the high-pressure cylinder rotor speed deviation is h And the per-unit value of power deviation ΔP e Perform low-frequency oscillation suppression processing to obtain a low-frequency oscillation control signal U pss ,include:

[0018] The per-unit value ΔW of the generator speed deviation g And the per-unit value of power deviation ΔP e Input into the second pre-processing link to obtain ultra-low frequency signal and low frequency signal;

[0019] The ultra-low frequency signal and the low frequency signal pass through the notch filter, then enter the phase shift compensation link, and finally enter the proportional amplification and limiting link to obtain the low frequency oscillation suppression signal U pss .

[0020] Preferably, the per-unit value ΔW of the generator speed deviation is g And the per-unit value of power deviation ΔP e Input the second pre-processing link to obtain ultra-low frequency signal and low frequency signal, including:

[0021] The per-unit value of the generator speed deviation ΔW g Obtaining an ultra-low frequency signal through a first low-pass filter;

[0022] The per-unit value of the power deviation ΔP e The signal is passed through a second low-pass filter to obtain a low-frequency signal.

[0023] Preferably, the subsynchronous oscillation suppression signal U sso and the low frequency oscillation suppression signal U pss The input excitation control system comprehensively suppresses low-frequency oscillations and subsynchronous oscillations, including:

[0024] The low frequency oscillation suppression signal U pss The terminal voltage reference value U superimposed on the excitation control system ref and the sub-synchronous oscillation suppression signal U sso The final output comprehensive control value U of the superimposed excitation control system f On the other hand, low-frequency oscillations and subsynchronous oscillations are comprehensively suppressed.

[0025] Preferably, the per-unit value of the power deviation ΔP e , calculated as follows:

[0026] ΔP e＝ ΔP / P ref

[0027] Where ΔP e is the per-unit value of power deviation; P ref is the active power reference value; ΔP is the active power deviation;

[0028] The per-unit value ΔW of the generator speed deviation g , calculated as follows:

[0029] ΔW g＝ ΔW1 / W ref

[0030] In the formula, ΔW g is the per-unit value of the generator speed deviation; W ref is the generator rotor speed reference value, ΔW1 is the generator rotor speed deviation;

[0031] The per-unit value ΔW of the high-pressure cylinder rotor speed deviation h , calculated as follows:

[0032] ΔW h＝ ΔW2 / W href

[0033] In the formula, ΔW h W is the per-unit value of the high-pressure cylinder rotor speed deviation; href is the reference value of the high-pressure cylinder rotor speed, and ΔW2 is the high-pressure cylinder rotor speed deviation.

[0034] A damping control system for suppressing low-frequency oscillation and subsynchronous oscillation, comprising:

[0035] Calculation module: used to calculate the per-unit value ΔW of the high-pressure cylinder rotor speed deviation based on the unit operating parameters h、 Per-unit value of power deviation ΔP e and the per-unit value of the generator speed deviation ΔW g ;

[0036] Subsynchronous oscillation suppression module: used to set the per-unit value ΔW of the high-pressure cylinder rotor speed deviation h and the per-unit value of the generator speed deviation ΔW g Perform subsynchronous oscillation suppression processing to obtain the subsynchronous oscillation control signal U sso ;

[0037] Low frequency oscillation suppression module: used to set the per-unit value ΔW of the high pressure cylinder rotor speed deviation h And the per-unit value of power deviation ΔP e Perform low-frequency oscillation suppression processing to obtain a low-frequency oscillation control signal U pss ;

[0038] Comprehensive suppression module: used to suppress the subsynchronous oscillation signal U sso and the low frequency oscillation suppression signal U pss The input excitation control system comprehensively suppresses low-frequency oscillation and subsynchronous oscillation;

[0039] The unit operating parameters include: a high-pressure cylinder rotor speed reference value and a measured high-pressure cylinder rotor speed value, an active power reference value and a measured active power value, and a generator rotor speed reference value and a measured generator rotor speed value.

[0040] Preferably, the calculation module includes: the per-unit value ΔP of the power deviation e , calculated as follows:

[0041] ΔP e＝ ΔP / P ref

[0042] Where ΔP e is the per-unit value of power deviation; P ref is the active power reference value; ΔP is the active power deviation;

[0043] The per-unit value ΔW of the generator speed deviation g , calculated as follows:

[0044] ΔW g＝ ΔW1 / W ref

[0045] In the formula, ΔW g is the per-unit value of the generator speed deviation; W ref is the generator rotor speed reference value, ΔW1 is the generator rotor speed deviation;

[0046] The per-unit value ΔW of the high-pressure cylinder rotor speed deviation h , calculated as follows:

[0047] ΔW h＝ ΔW2 / Whref

[0048] In the formula, ΔW h W is the per-unit value of the high-pressure cylinder rotor speed deviation; href is the reference value of the high-pressure cylinder rotor speed, and ΔW2 is the high-pressure cylinder rotor speed deviation.

[0049] Preferably, the subsynchronous oscillation suppression module specifically includes:

[0050] The per-unit value ΔW of the generator speed deviation g and the per-unit value ΔW of the high-pressure cylinder rotor speed deviation h Input the first pre-processing, use the weighted combination algorithm to construct the comprehensive feedback signal as the weighted combination speed signal;

[0051] The weighted combined speed signal passes through a bandpass filter, then enters the phase shift compensation link, and finally enters the proportional amplification and limiting link to obtain the subsynchronous oscillation suppression signal U sso .

[0052] Preferably, the low-frequency oscillation suppression module specifically includes: an ultra-low-frequency signal unit and a low-frequency signal unit;

[0053] The ultra-low frequency signal unit is used to convert the per-unit value ΔW of the generator speed deviation into g Obtaining an ultra-low frequency signal through a first low-pass filter;

[0054] The low frequency signal unit converts the per-unit value of the power deviation ΔP e The signal is passed through a second low-pass filter to obtain a low-frequency signal.

[0055] Preferably, the comprehensive suppression module specifically includes:

[0056] The low frequency oscillation suppression signal U pss The terminal voltage reference value U superimposed on the excitation control system ref and the sub-synchronous oscillation suppression signal U sso The final output comprehensive control value U of the superimposed excitation control system f On the other hand, low-frequency oscillations and subsynchronous oscillations are comprehensively suppressed.

[0057] Compared with the closest existing technology, the technical solution provided by the present invention has the following beneficial effects:

[0058] 1. The present invention provides a damping control method for suppressing low-frequency oscillations and subsynchronous oscillations, comprising: calculating a per-unit value ΔWh of a high-pressure cylinder rotor speed deviation, a per-unit value ΔPe of a power deviation, and a per-unit value ΔWg of a generator speed deviation based on unit operating parameters; performing subsynchronous oscillation suppression processing on the per-unit value ΔWh of the high-pressure cylinder rotor speed deviation and the per-unit value ΔWg of the generator speed deviation to obtain a subsynchronous oscillation control signal Usso; performing low-frequency oscillation suppression processing on the per-unit value ΔWh of the high-pressure cylinder rotor speed deviation and the per-unit value ΔPe of the power deviation to obtain a low-frequency oscillation control signal Upss; inputting the subsynchronous oscillation suppression signal Usso and the low-frequency oscillation suppression signal Upss into an excitation control system to comprehensively suppress low-frequency oscillations and subsynchronous oscillations; wherein the unit operating parameters include: a high-pressure cylinder rotor speed reference value and a measured high-pressure cylinder rotor speed value, an active power reference value and a measured active power value, and a generator rotor speed reference value and a measured generator rotor speed value. It effectively solves the problem that the suppression of low-frequency oscillations and subsynchronous oscillations or controllers are often designed independently and implemented by relying on different control devices, and there is a lack of coordination between different controls. In addition, the method of implementing additional control on the existing system is easy to implement, and takes into account the ultra-low frequency oscillation mode, with a comprehensive range of action.

[0059] 2. The damping controller proposed in the present invention is designed with a pure phase compensation link with a gain of 1, which is convenient for adjusting the gain and phase separately; and the compensator can select a single or multiple lead-lag links according to different needs, which has good applicability.

[0060] 3. The damping controller proposed in the present invention can be implemented based on the excitation control system (or reactive power / voltage control system) of various power sources such as thermal power units, hydropower units, and new energy units (including wind turbines and photovoltaic power generation systems). It is economical and has universal application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a flow chart of a damping control method for suppressing low-frequency oscillation and subsynchronous oscillation according to the present invention;

[0062] Figure 2 is a block diagram of a damping controller for simultaneously suppressing low-frequency oscillation and subsynchronous oscillation in an embodiment of the present invention;

[0063] Figure 3 1 is a diagram showing the effect of a bandpass filter for suppressing subsynchronous oscillations in an embodiment of the present invention;

[0064] Figure 4 1 is an effect diagram of a notch filter according to an embodiment of the present invention;

[0065] Figure 5 2 is an effect diagram of the phase shift compensation link in an embodiment of the present invention.

[0066] Figures 3 to 5 In the figure, 1 is the amplitude (abs) marked on the vertical coordinate; 2 is the phase (deg) marked on the vertical coordinate; 3 is the frequency (Hz) marked on the horizontal coordinate; A is the point with a frequency of 15.2 and an amplitude of 0.00204; B is the point with a frequency of 26 and an amplitude of 0.96; C is the point with a frequency of 30.5 and an amplitude of 0.0744; D is the point with a frequency of 15.2 and a phase of 248; E is the point with a frequency of 26 and a phase of -1.57; F is the point with a frequency of 30.5 and a phase of -198. DETAILED DESCRIPTION

[0067] To better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0068] Example 1

[0069] The present invention proposes a damping control method and system for simultaneously suppressing low-frequency oscillations and subsynchronous oscillations. The controller takes into account the ultra-low-frequency oscillation mode and designs a pure phase compensation link with a gain of 1, which facilitates parameter setting. The controller can be implemented based on the excitation control system (or reactive power / voltage control system) of various power sources such as thermal power units, hydropower units, and new energy units (including wind turbines and photovoltaic power generation systems). It has good economic efficiency and has universal promotion and application value.

[0070] 1. A damping control method for suppressing low-frequency oscillation and subsynchronous oscillation, comprising:

[0071] The per-unit value ΔW of the high-pressure cylinder rotor speed deviation is calculated based on the unit operating parameters h、 Per-unit value of power deviation ΔP e and the per-unit value of the generator speed deviation ΔW g ;

[0072] The per-unit value ΔW of the high-pressure cylinder rotor speed deviation h and the per-unit value of the generator speed deviation ΔW g Perform subsynchronous oscillation suppression processing to obtain the subsynchronous oscillation control signal U sso ;

[0073] The per-unit value ΔW of the high-pressure cylinder rotor speed deviation h And the per-unit value of power deviation ΔP e Perform low-frequency oscillation suppression processing to obtain a low-frequency oscillation control signal Upss ;

[0074] The subsynchronous oscillation suppression signal U sso and the low frequency oscillation suppression signal U pss Input excitation control system to comprehensively suppress low-frequency oscillation and subsynchronous oscillation;

[0075] The unit operating parameters include: a high-pressure cylinder rotor speed reference value and a measured high-pressure cylinder rotor speed value, an active power reference value and a measured active power value, and a generator rotor speed reference value and a measured generator rotor speed value.

[0076] S1 calculates the per-unit value ΔW of the high-pressure cylinder rotor speed deviation based on the unit operating parameters h、 Per-unit value of power deviation ΔP e and the per-unit value of the generator speed deviation ΔW g ;

[0077] Step 1: Measure and obtain the output active power P of the synchronous generator set or new energy unit in the system e , and the reference value of active power P ref Calculate the per-unit value of power deviation ΔP together e ; Measure and obtain the rotor speed W of the synchronous generator set in the system g , and the reference value of the rotor speed W ref Calculate the per-unit value of the generator speed deviation ΔW together g ;Measure and obtain the high-pressure cylinder rotor speed W of the synchronous generator set in the system h , and the reference value W of the high-pressure cylinder rotor speed href Calculate together to get the per-unit value ΔW of the high-pressure cylinder rotor speed deviation h .

[0078] In step 1, ΔP e＝ ΔP / P ref ; ΔW g＝ ΔW1 / W ref ; ΔW h＝ ΔW2 / W href

[0079] Where: P ref is the active power reference value, ΔP is the active power deviation, ΔP=P ref -P e , P is the measured amplitude of active power output; W ref is the generator rotor speed reference value, ΔW1 is the rotor speed deviation, ΔW1=W ref -W g , W g is the measured amplitude of the generator rotor speed; Whref is the reference value of the high-pressure cylinder rotor speed, ΔW2 is the high-pressure cylinder rotor speed deviation, ΔW2 = W href -W h , W h It is the measured amplitude of the high-pressure cylinder rotor speed of the generator set.

[0080] S2 sets the per-unit value ΔW of the high-pressure cylinder rotor speed deviation h and the per-unit value of the generator speed deviation ΔW g Subsynchronous oscillation suppression processing is performed to obtain a subsynchronous oscillation control signal U sso ;

[0081] Step 2: Convert the signal ΔW g and ΔW h The first pre-processing link is input to obtain a weighted combined speed signal; then it enters the bandpass filter (different filter center frequency points are designed to be subsynchronous oscillation frequency points), and by setting a reasonable bandwidth, it avoids affecting low-frequency oscillation; then it enters the phase shift compensation link (the phase shift compensation link is designed to have a gain of 1, which is convenient for adjusting the gain and phase separately); then it enters the proportional amplification and limiting links respectively; finally, after the total output limiting link, the subsynchronous oscillation suppression signal U is obtained. sso This signal is generally superimposed on the final output value U of the excitation control system (or reactive power / voltage control system) of various power sources such as thermal power units, hydropower units, and new energy units (including wind turbines and photovoltaic power generation systems). f superior.

[0082] In step 2, the first pre-processing link uses a weighted combination algorithm to construct a comprehensive feedback signal based on the speed signals of the generator side and the high-pressure cylinder side of the unit, without losing the controlled modal components, while suppressing the uncontrolled modal components as much as possible, which is conducive to modal separation control. The number of bandpass filters is determined according to the number of subsynchronous oscillation frequency points. Each bandpass filter corresponds to a subsynchronous oscillation frequency point, and the bandwidth of the bandpass filter is generally designed to be 14%. The phase shift compensation link adopts the form of (Ts-1) / (Ts+1), so that its gain is always 1, and the phase can be adjusted by adjusting the T parameter. The total output limiting link is used to control U sso The amplitude of the signal is generally designed to be ±5% or ±10% to avoid a major impact on the normal control of the system.

[0083] S3: the per-unit value ΔW of the high-pressure cylinder rotor speed deviation h And the per-unit value of power deviation ΔP e Perform low-frequency oscillation suppression processing to obtain a low-frequency oscillation control signal U pss ;

[0084] Step 3: Convert the signal ΔW gWith ΔP e Input the second pre-processing link to obtain ultra-low frequency signal and low frequency signal; then enter the notch filter (different notch frequency points are designed to be subsynchronous oscillation frequency points) to avoid affecting subsynchronous oscillation; then enter the phase shift compensation link (the phase shift compensation link is designed to have a gain of 1, which is convenient for adjusting the gain and phase separately); then enter the proportional amplification and limiting links respectively; finally, after the total output limiting link, the low-frequency oscillation suppression signal U is obtained. pss This signal is generally superimposed on the reference value U of the excitation control system (or reactive power / voltage control system) of various power sources such as thermal power units, hydropower units, and new energy units (including wind turbines and photovoltaic power generation systems). ref superior.

[0085] In step 3, the second pre-processing step includes two parts. The first part is to convert ΔW g The signal is passed through low-pass filter 1 to obtain ultra-low frequency signal. The second part is to convert ΔP e The signal is passed through low-pass filter 2 to obtain a low-frequency signal. Low-pass filter 1 can be set to: Low-pass filter 2 can be set to: Where H is the unit inertia time constant (unit: seconds); the notch filter is set to: Where W ni is the notch filter frequency, B wi The total output limiter is used to control U pss The amplitude of the signal is generally designed to be ±5% or ±10% to avoid a major impact on the normal control of the system.

[0086] S4 converts the sub-synchronous oscillation suppression signal U sso and the low frequency oscillation suppression signal U pss The input excitation control system comprehensively suppresses low-frequency oscillation and subsynchronous oscillation;

[0087] Step 4: U sso with U pss The signals act together through the excitation control systems (or reactive power / voltage control systems) of various power sources such as thermal power units, hydropower units, and new energy units (including wind turbines and photovoltaic power generation systems), thereby comprehensively suppressing low-frequency oscillations (including ultra-low frequency oscillations) and subsynchronous oscillations.

[0088] In step 4, U sso with U pss The signal can act simultaneously on the excitation control system of conventional power sources such as thermal power units and hydropower units; it can also act simultaneously on the reactive power / voltage control system of new energy sources such as wind turbines and photovoltaic power generation systems.

[0089] Figure 2This is a block diagram of the damping controller proposed in the present invention for simultaneously suppressing low-frequency oscillation and subsynchronous oscillation. Figure 3 The effect of the bandpass filter (center frequency 26Hz, bandwidth 14%) used to suppress subsynchronous oscillations, Figure 4 This is the effect diagram of the notch filter (center frequency 26Hz, 3dB bandwidth 10%). Figure 4 This is the effect diagram of the phase shift compensation link (T=0.2). Figure 2-Figure 5 It can be seen that the amplitude-frequency and phase-frequency effects of each key link are accurate, which verifies the effectiveness and practicality of the damping controller proposed in the present invention.

[0090] The specific implementation method of the present invention uses a typical parameter as an example to illustrate the design effect of the key links of the controller, and is also applicable to different design parameters. The damping control method and system for simultaneously suppressing low-frequency oscillations and subsynchronous oscillations proposed in the present invention fills the gap in comprehensive suppression controllers covering ultra-low frequency, low frequency and subsynchronous frequency bands at home and abroad, and can be implemented based on the excitation control system / reactive voltage control system of various conventional power supplies and new energy units. It is economical and has good practical promotion value. By superimposing the damping controller on the existing control loop of conventional power supplies and new energy units, the physical concept is clear, simple and easy to use, and it is easy for power industry engineers and scientific researchers at different knowledge levels to master and use. The method described in the present invention is universal and can be easily extended to various power generation systems and other similar systems to solve the problem of oscillation suppression in different frequency bands, and has broad application prospects.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

[0092] Example 2

[0093] Based on the same concept, the present invention also provides a damping control system for suppressing low-frequency oscillations and subsynchronous oscillations, comprising:

[0094] Calculation module: used to calculate the per-unit value ΔW of the high-pressure cylinder rotor speed deviation based on the unit operating parameters h、 Per-unit value of power deviation ΔP e and the per-unit value of the generator speed deviation ΔW g ;

[0095] Subsynchronous oscillation suppression module: used to set the per-unit value ΔW of the high-pressure cylinder rotor speed deviation h and the per-unit value of the generator speed deviation ΔWg Perform subsynchronous oscillation suppression processing to obtain the subsynchronous oscillation control signal U sso ;

[0096] Low frequency oscillation suppression module: used to set the per-unit value ΔW of the high pressure cylinder rotor speed deviation h And the per-unit value of power deviation ΔP e Perform low-frequency oscillation suppression processing to obtain a low-frequency oscillation control signal U pss ;

[0097] Comprehensive suppression module: used to suppress the subsynchronous oscillation signal U sso and the low frequency oscillation suppression signal U pss Input excitation control system to comprehensively suppress low-frequency oscillation and subsynchronous oscillation;

[0098] The unit operating parameters include: a high-pressure cylinder rotor speed reference value and a high-pressure cylinder rotor speed actual value, an active power reference value and an active power actual value, and a generator rotor speed reference value and a rotor speed actual value.

[0099] The calculation module includes: the per-unit value ΔP of the power deviation e , calculated as follows:

[0100] ΔP e＝ ΔP / P ref

[0101] Where ΔP e is the per-unit value of power deviation; P ref is the active power reference value; ΔP is the active power deviation;

[0102] The per-unit value ΔW of the generator speed deviation g , calculated as follows:

[0103] ΔW g＝ ΔW1 / W ref

[0104] In the formula, ΔW g is the per-unit value of the generator speed deviation; W ref is the generator rotor speed reference value, ΔW1 is the generator rotor speed deviation;

[0105] The per-unit value ΔW of the high-pressure cylinder rotor speed deviation h , calculated as follows:

[0106] ΔW h＝ ΔW2 / W href

[0107] In the formula, ΔW hW is the per-unit value of the high-pressure cylinder rotor speed deviation; href is the reference value of the high-pressure cylinder rotor speed, and ΔW2 is the high-pressure cylinder rotor speed deviation.

[0108] The subsynchronous oscillation suppression module specifically includes:

[0109] The per-unit value ΔW of the generator speed deviation g and the per-unit value ΔW of the high-pressure cylinder rotor speed deviation h The first pre-processing link is input and a weighted combination algorithm is used to construct a comprehensive feedback signal as a weighted combined speed signal;

[0110] The weighted combined speed signal passes through a bandpass filter, then enters the phase shift compensation link, and finally enters the proportional amplification and limiting link to obtain the subsynchronous oscillation suppression signal U sso .

[0111] The low-frequency oscillation suppression module specifically includes: an ultra-low-frequency signal unit and a low-frequency signal unit;

[0112] The ultra-low frequency signal unit is used to convert the per-unit value ΔW of the generator speed deviation into g Obtaining an ultra-low frequency signal through a first low-pass filter;

[0113] The low frequency signal unit converts the per-unit value of the power deviation ΔP e The signal is passed through a second low-pass filter to obtain a low-frequency signal.

[0114] The comprehensive suppression module specifically includes:

[0115] The low frequency oscillation suppression signal U pss The terminal voltage reference value U superimposed on the excitation control system ref and the sub-synchronous oscillation suppression signal U sso The final output comprehensive control value U of the superimposed excitation control system f On the other hand, low-frequency oscillations and subsynchronous oscillations are comprehensively suppressed.

[0116] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0117] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0118] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0119] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0120] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of the claims of the present invention to be approved.

Claims

1. A damping control method for suppressing low-frequency oscillation and subsynchronous oscillation, characterized in that: include: The per-unit value of the high-pressure cylinder rotor speed deviation is calculated based on the unit operating parameters , per-unit value of power deviation The per-unit value of the generator speed deviation ; The per-unit value of the high-pressure cylinder rotor speed deviation The per-unit value of the generator speed deviation Perform subsynchronous oscillation suppression processing to obtain the subsynchronous oscillation control signal U sso ; The per-unit value of the generator speed deviation and per-unit value of power deviation Perform low-frequency oscillation suppression processing to obtain a low-frequency oscillation control signal U pss ; The per-unit value of the generator speed deviation and per-unit value of power deviation Input into the second pre-processing link to obtain ultra-low frequency signal and low frequency signal; The per-unit value of the generator speed deviation Obtain the ultra-low frequency signal through the first low-pass filter; The low-frequency signal is obtained through the second low-pass filter; the ultra-low-frequency signal and the low-frequency signal pass through the notch filter, then enter the phase shift compensation link, and finally enter the proportional amplification and limiting link to obtain the low-frequency oscillation control signal U pss ; The sub-synchronous oscillation control signal U sso and the low frequency oscillation control signal U pss Input excitation control system to comprehensively suppress low-frequency oscillation and subsynchronous oscillation; The unit operating parameters include: a high-pressure cylinder rotor speed reference value and a measured high-pressure cylinder rotor speed value, an active power reference value and a measured active power value, and a generator rotor speed reference value and a measured generator rotor speed value.

2. The damping control method for suppressing low-frequency oscillation and subsynchronous oscillation according to claim 1, characterized in that: The subsynchronous oscillation suppression process is performed on the per-unit value of the high-pressure cylinder rotor speed deviation and the per-unit value of the generator speed deviation to obtain a subsynchronous oscillation control signal Usso, including: The per-unit value of the generator speed deviation and the per-unit value of the high-pressure cylinder rotor speed deviation The first pre-processing link is input and a weighted combination algorithm is used to construct a comprehensive feedback signal as a weighted combined speed signal; The weighted combined speed signal passes through a bandpass filter, then enters the phase shift compensation link, and finally enters the proportional amplification and amplitude limiting link to obtain the sub-synchronous oscillation control signal U sso .

3. The damping control method for suppressing low-frequency oscillation and subsynchronous oscillation according to claim 1, characterized in that: Inputting the subsynchronous oscillation control signal Usso and the low-frequency oscillation control signal Upss into an excitation control system to comprehensively suppress low-frequency oscillation and subsynchronous oscillation, including: The low frequency oscillation control signal U pss The terminal voltage reference value U superimposed on the excitation control system ref and the sub-synchronous oscillation control signal U sso The final output comprehensive control value U superimposed on the excitation control system f On the other hand, low-frequency oscillations and subsynchronous oscillations are comprehensively suppressed.

4. The damping control method for suppressing low-frequency oscillation and subsynchronous oscillation according to claim 1, characterized in that: The per-unit value of the power deviation , calculated as follows: Where, is the per-unit value of power deviation; P ref is the active power reference value; is the active power deviation; The per-unit value of the generator speed deviation , calculated as follows: Where, is the per-unit value of the generator speed deviation; W ref is the generator rotor speed reference value, is the generator rotor speed deviation; The per-unit value of the high-pressure cylinder rotor speed deviation , calculated as follows: Where, W is the per-unit value of the high-pressure cylinder rotor speed deviation; href is the reference value of the high-pressure cylinder rotor speed, is the speed deviation of the high-pressure cylinder rotor.

5. A damping control system for suppressing low-frequency oscillations and subsynchronous oscillations, characterized in that: include: Calculation module: used to calculate the per-unit value of the high-pressure cylinder rotor speed deviation based on the unit operating parameters 、 Per-unit value of power deviation The per-unit value of the generator speed deviation ; Subsynchronous oscillation suppression module: used to set the per-unit value of the high-pressure cylinder rotor speed deviation The per-unit value of the generator speed deviation Perform subsynchronous oscillation suppression processing to obtain the subsynchronous oscillation control signal U sso ; Low frequency oscillation suppression module: used to convert the per-unit value of the generator speed deviation and per-unit value of power deviation Perform low-frequency oscillation suppression processing to obtain a low-frequency oscillation control signal U pss : The per-unit value of the generator speed deviation and per-unit value of power deviation Input the second pre-processing link to obtain ultra-low frequency signal and low frequency signal; the per-unit value of the generator speed deviation Obtain the ultra-low frequency signal through the first low-pass filter; The low-frequency signal is obtained through the second low-pass filter; the ultra-low-frequency signal and the low-frequency signal pass through the notch filter, then enter the phase shift compensation link, and finally enter the proportional amplification and limiting link to obtain the low-frequency oscillation control signal U pss ; Comprehensive suppression module: used to convert the sub-synchronous oscillation control signal U sso and the low frequency oscillation control signal U pss Input excitation control system to comprehensively suppress low-frequency oscillation and subsynchronous oscillation; The unit operating parameters include: a high-pressure cylinder rotor speed reference value and a measured high-pressure cylinder rotor speed value, an active power reference value and a measured active power value, and a generator rotor speed reference value and a measured generator rotor speed value.

6. A damping control system for suppressing low-frequency oscillation and subsynchronous oscillation according to claim 5, characterized in that: The calculation module includes: the per-unit value of the power deviation is calculated according to the following formula: Where, is the per-unit value of power deviation; P ref is the active power reference value; is the active power deviation; The per-unit value of the generator speed deviation , calculated as follows: Where, is the per-unit value of the generator speed deviation; W ref is the generator rotor speed reference value, is the generator rotor speed deviation; The per-unit value of the high-pressure cylinder rotor speed deviation , calculated as follows: Where, W is the per-unit value of the high-pressure cylinder rotor speed deviation; href is the reference value of the high-pressure cylinder rotor speed, is the speed deviation of the high-pressure cylinder rotor.

7. A damping control system for suppressing low-frequency oscillation and subsynchronous oscillation according to claim 5, characterized in that: The subsynchronous oscillation suppression module specifically includes: The per-unit value of the generator speed deviation and the per-unit value of the high-pressure cylinder rotor speed deviation The first pre-processing link is input and a weighted combination algorithm is used to construct a comprehensive feedback signal as a weighted combined speed signal; The weighted combined speed signal passes through a bandpass filter, then enters the phase shift compensation link, and finally enters the proportional amplification and amplitude limiting link to obtain the sub-synchronous oscillation control signal U sso .

8. A damping control system for suppressing low-frequency oscillation and subsynchronous oscillation according to claim 5, characterized in that: The comprehensive suppression module specifically includes: The low frequency oscillation control signal U pss The terminal voltage reference value U superimposed on the excitation control system ref and the sub-synchronous oscillation control signal U sso The final output comprehensive control value U superimposed on the excitation control system f On the other hand, low-frequency oscillations and subsynchronous oscillations are comprehensively suppressed.

Images