Equivalent simulation test method and system for sub-synchronous oscillation and super-synchronous oscillation of double-frequency coupling type synchronous motor
By constructing a dual-frequency coupled synchronous motor and supersynchronous oscillation equivalent simulation test method, the signal generation problem of the broadband oscillation measurement device is solved, efficient and accurate wideband oscillation monitoring is achieved, and the safety and stability of the power system is promoted.
Patent Information
- Application Number
- CN202510294087.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-13
- Publication Date
- 2025-07-11
AI Technical Summary
The existing broadband oscillation measurement devices are difficult to accurately simulate and generate power grid oscillation signals in power systems, resulting in the problem of broadband oscillation monitoring not being effectively solved. Traditional PMUs cannot meet the requirements of broadband oscillation measurement and lack effective detection tools and methods.
A dual-frequency coupled synchronous motor number and oversynchronous oscillation equivalent simulation test method is constructed. By constructing the motor stator voltage time domain disturbance equation, the motor stator voltage is simulated, and the electrical quantity of oversynchronous oscillation is selected, and the appropriate parameters are selected to oscillate the line, generating a signal close to the actual power grid for testing.
The test process is simplified, the cost and complexity is reduced, the testing efficiency and accuracy of broadband oscillation monitoring equipment is improved, and the theoretical basis is provided to understand the phenomenon of sub- and super-synchronous oscillation, which promotes the research and development and standardization of broadband oscillation monitoring equipment, and improves the safety and stability of the power system.
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Figure CN120294559A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an oscillation equivalent simulation test method and system, and particularly to a dual-frequency coupled synchronous motor sub-synchronous and super-synchronous oscillation equivalent simulation test method and system. Background Art
[0002] With the continuous development of modern power systems, a high proportion of new energy and power electronic devices are connected to the grid, and the oscillation characteristics of the power system have changed significantly, showing new spatial and temporal characteristics. In a "dual-high" power system, due to internal or external factors, the interaction between power electronic devices and between them and the grid will cause electrical quantities to fluctuate periodically over time, and the oscillation frequency coverage range is extremely wide, varying between 0 - 2500 Hz. This dynamic process is called wide-frequency oscillation of the power system. Wide-frequency oscillation can be further subdivided according to the oscillation frequency band of power, where the low-frequency oscillation frequency range is 0.1 Hz - 2.5 Hz, the sub-synchronous oscillation is 2.5 Hz - 45 Hz, the super-synchronous oscillation is 55 Hz - 95 Hz, the medium-frequency band oscillation is 95 Hz - 300 Hz, and the high-frequency band oscillation is 300 Hz - 2500 Hz. The power grid is essentially a complex non-linear system, and the high proportion of power electronics has greatly increased the difficulty of analyzing and suppressing power system oscillations. To solve the oscillation problem at its root, it is first necessary to overcome the problem of wide-frequency oscillation monitoring.
[0003] Traditional phasor measurement units (PMUs) usually use low-pass filters to ensure measurement accuracy. The design purpose is to ensure that signals in the 45 - 55 Hz range can be accurately measured, but this also makes it unable to meet the requirements of wide-frequency oscillation measurement. Therefore, developing new measurement devices has become an urgent need in the power industry. With the gradual deepening of research, both the State Grid and China Southern Power Grid Corporation have formulated relevant technical specifications for wide-frequency oscillation measurement devices, promoting the research of equipment towards standardization and attempting to replace traditional PMUs.
[0004] In recent years, the research and development of wide-frequency measurement devices have received extensive attention. However, the analog generation link of grid oscillation signals has not been given enough attention, and there are still many problems to be solved in the detection tools and methods of wide-frequency oscillation measurement devices. Summary of the Invention
[0005] Object of the Invention: The object of the present invention is to provide a dual-frequency coupled synchronous motor sub-synchronous and super-synchronous oscillation equivalent simulation test method to improve the test efficiency of wide-frequency oscillation monitoring equipment, thereby improving the safety and stability of the power system.
[0006] Technical Solution: A dual-frequency coupled synchronous motor sub-synchronous and super-synchronous oscillation equivalent simulation test method according to the present invention includes:
[0007] (1) Construct an equivalent model of the oscillating voltage of a dual - frequency coupled synchronous motor, and express the post - fault voltage as the sum of four terms, specifically including the steady - state quantity, the sub - synchronous frequency term, the super - synchronous frequency term, and the remainder term;
[0008] (2) According to the time - domain perturbation equation of the motor stator voltage, construct a sub - synchronous and super - synchronous signal test circuit to simulate the electrical quantities during sub - synchronous and super - synchronous oscillations;
[0009] (3) Select appropriate parameters to make the line oscillate, and determine the series compensation ratio and resonance frequency. The parameters include resistance, inductance, and capacitance;
[0010] (4) Obtain or directly adopt the voltages, phase angles, and power angles at the generator terminal and the grid terminal, and select an appropriate angular displacement increment amplitude to control the resonance power to meet the test requirements.
[0011] Preferably, the expression of the sum of the four terms in step 1 is:
[0012] Steady - state quantity: e a0 = u a0 = U m cos(ω0t + α u );
[0013] Sub - synchronous frequency term:
[0014] Super - synchronous frequency term:
[0015] Remainder term: e a0 = Δu” a = -(cost·Δψ q + sint·Δψ d );
[0016] Among them, U m represents the voltage amplitude, ω0 represents the rated frequency, α u represents the initial phase angle of the generator voltage under the condition that the direct axis of the rotor coincides with the a - phase axis at t = 0, A represents the angular displacement increment amplitude, ω m represents the natural torsional vibration frequency, Δψ q and Δψ d represent the changes in magnetic flux in the dq0 coordinate system, e a0 , e ss , e os represent the decomposed quantities of the equivalent parameters of the terminal voltage of the machine.
[0017] Preferably, when constructing the sub - synchronous and super - synchronous signal test circuits in step 2, the decomposed quantities of the equivalent parameters of the terminal voltage of the machine are connected to the power grid through an RLC equivalent circuit. For the perturbation voltage equation, let the remainder term be 0, and use the superposition principle to calculate the power - frequency, sub - synchronous frequency, and super - synchronous frequency components respectively, and finally combine them to obtain the full - voltage current quantity.
[0018] Preferably, when selecting appropriate parameters to make the line oscillate in step 3, when the line series compensation degree and the natural torsional oscillation frequency satisfy the relationship K = (1 - ω m / ω0) 2 , sub-synchronous resonance occurs in the system, and sub-synchronous and super-synchronous frequencies always appear in pairs, and the sum of the two is twice the power frequency, satisfying the relationship ω m = (ω os - ω ss ) / 2, where K represents the line series compensation degree, ω m represents the natural torsional oscillation frequency, ω ss represents the sub-synchronous frequency, and ω os represents the super-synchronous frequency.
[0019] Preferably, the formula for the resonance power in step 4 is P ss = P ssm {1 + cos[2(ω0 - ω m )t + 2α u}, and the active oscillation power during actual measurement is the average value of the instantaneous value within one period. For periodic oscillation, this average value is a constant. For oscillatory divergence, the power amplitude is changed in a stepwise manner to detect the action threshold of the broadband measurement device.
[0020] Preferably, in step 4, selecting an appropriate angular displacement increment amplitude to control the resonance power to meet the test requirements, where the range of the angular displacement increment amplitude is 0 to π / 12, and extremely not exceeding π / 6.
[0021] Preferably, when obtaining the initial phase angles at the generator end and the grid end in step 4, based on the internal impedance of the generator, the loop current, the line power factor, and the voltage at the generator outlet, the generator power angle can be obtained first, and then the initial phase angle at the generator end can be obtained. For the initial phase angle at the grid end, only the line impedance angle needs to be considered.
[0022] A dual-frequency coupled synchronous motor sub-synchronous and super-synchronous oscillation equivalent simulation test system according to the present invention includes:
[0023] A model establishment module for establishing an equivalent model of the sub-synchronous and super-synchronous oscillation voltages of a dual-frequency coupled synchronous motor;
[0024] A circuit construction module for constructing a sub-synchronous and super-synchronous signal test circuit according to the time-domain disturbance equation of the motor stator voltage;
[0025] A parameter selection module for selecting appropriate parameters to make the line oscillate;
[0026] A power calculation and control module for calculating the instantaneous oscillation power according to the test circuit and selecting an appropriate angular displacement increment amplitude to control the sub-synchronous resonance power to meet the test requirements.
[0027] A computer device includes one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and when the programs are executed by the processors, the steps of a dual-frequency coupled synchronous motor sub- and supersynchronous oscillation equivalent simulation test method as described in any one of claims 1-7 are implemented.
[0028] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of a dual-frequency coupled synchronous motor sub- and supersynchronous oscillation equivalent simulation test method as described in any one of claims 1-7 are implemented.
[0029] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: 1. The operation is relatively simple, without the need for high-cost equipment investment. While ensuring the accuracy of the simulation test, the test cost and complexity are greatly reduced, making it more convenient to promote and apply in engineering practice, and helping to improve the research and test efficiency of broadband oscillation monitoring equipment; 2. Through the simulated signal close to the actual power grid oscillation, researchers can more comprehensively and accurately test and evaluate the performance of broadband oscillation monitoring equipment in the sub- and supersynchronous oscillation environment, including key indicators such as measurement accuracy, response time, and action threshold, thereby promoting the research and improvement of broadband oscillation monitoring equipment and enhancing the safety and stability of the power system; 3. By constructing a dual-frequency coupled synchronous motor sub- and supersynchronous oscillation voltage equivalent model, the relationship between the shaft oscillation frequency and the generator stator voltage component is clearly revealed, providing a theoretical basis for researchers to understand the sub- and supersynchronous oscillation phenomenon. Compared with the traditional simple harmonic superposition simulation method, it can more accurately reflect the physical essence of the power grid oscillation; 4. It has a test signal generation algorithm with clear physical meaning and a reliable test system, providing a unified and effective means for the detection of broadband oscillation measurement devices, helping to promote the standardization process of broadband oscillation monitoring equipment research, and promoting the standardized development of the entire power industry in dealing with broadband oscillation problems. Description of the Drawings
[0030] Figure 1 It is a schematic diagram of the sub- and supersynchronous signal test circuit of the present invention. Detailed Embodiments
[0031] Next, in combination with the drawings, the technical solutions of the present invention will be described in detail.
[0032] This embodiment provides a dual-frequency coupled synchronous motor sub- and supersynchronous oscillation equivalent simulation test method:
[0033] (1) Construct an equivalent model of the oscillating voltage of a dual-frequency coupled synchronous motor. After analysis and simplification, the post-fault voltage is expressed as the sum of four terms, specifically including the steady-state quantity, the subsynchronous frequency term, the supersynchronous frequency term, and the remainder term. Taking phase a as an example:
[0034] u a = u a0 + u ss + u os + e r = e a0 + e ss + e os + e r ;
[0035] The first term, the steady-state quantity: e a0 = u a0 = U m cos(ω0t + α u );
[0036] The second term, the subsynchronous frequency term:
[0037] The third term, the supersynchronous frequency term:
[0038] The fourth term, the remainder term: e a0 = Δu” a = -(cos t·Δψ q + sin t·Δψ d );
[0039] Among them, U m represents the voltage amplitude, ω0 represents the rated frequency, α u represents the initial phase angle of the generator voltage under the condition that the direct axis of the rotor coincides with the a-phase axis at t = 0, A represents the amplitude of the angular displacement increment, ω m represents the natural torsional vibration frequency, Δψ q and Δψ d represent the flux linkage change in the dq0 coordinate system, e a0 , e ss , e os , e r represent the decomposed quantities of the equivalent parameters of the terminal voltage of the machine.
[0040] The model clearly demonstrates that when there is an oscillating component with a frequency of ω m in the shafting, voltage components with subsynchronous frequency (1 - ω m ) and supersynchronous frequency (1 + ω m ) will appear in the stator of the generator; if the resonance frequency of the stator circuit is exactly (1 - ω m ), a current component Δi' a corresponding to this frequency will be generated in the line, for the frequency ω in the shaftingm The oscillating component has a negative damping effect, thus forming mutual excitation between machinery and electricity. If this negative damping effect cancels out the total positive damping in the line, the oscillation will diverge;
[0041] The supersynchronous frequency (1 + ω m ) voltage component will also generate a current component of the corresponding frequency in the line. However, since the stator circuit resonance frequency generally does not exceed the synchronous frequency and the supersynchronous component produces a positive damping effect, supersynchronous resonance will not occur.
[0042] (2) Based on the time-domain perturbation equation of the generator stator voltage, construct a sub- and supersynchronous signal test circuit, connect to the power grid through an RLC equivalent circuit, and e s is the grid voltage; for the perturbation voltage equation, generally focus on e a0 , e ss , e os , that is, let the remainder e r be 0. In actual calculation, use the superposition principle to calculate the power frequency, sub-synchronous frequency, and supersynchronous frequency components respectively, and finally combine to obtain the full voltage current.
[0043] (3) Select reasonable parameters to make the line oscillate; the control of sub-synchronous resonance is achieved through the line series compensation degree K. When K and the natural torsional vibration frequency ω m satisfy the following relationship, sub-synchronous oscillation occurs:
[0044]
[0045] The sub- and supersynchronous frequencies (ω ss , ω os ) always appear in pairs, and the sum of the two is twice the power frequency, so there is:
[0046]
[0047] (4) Obtain the initial phase angles α u and α s at the generator end and the grid end: According to the internal impedance of the generator, the loop current, the line power factor, and the voltage at the generator outlet, the power angle δ of the generator can be obtained, and α u = -(90° + δ); for α s , only need to consider the line impedance angle δ s , that is, α s = α u - δ s , and the initial phase angles at the generator end and the grid end can also directly select the rated values, omitting the calculation process.
[0048] (5) Select an appropriate angular displacement increment amplitude A according to the test circuit to control the sub-synchronous oscillation power P ss, to meet the test requirements:
[0049] P ss = P ssm {1 + cos[2(ω0 - ω m )t + 2α u} ;
[0050]
[0051] The active power P during actual measurement ssm is the instantaneous value P ss averaged over one period (Tss). For periodic oscillation, this value is constant, i.e., P ssm ; for oscillatory divergence, the power amplitude can be changed in a step - by - step manner to detect the operating threshold of the broadband measurement device.
[0052] Select an appropriate angular displacement increment amplitude A to control the subsynchronous resonance power P ss , to meet the test requirements. However, A should not be too large, and the reasonable range is 0 to π / 12, and extremely not exceeding π / 6.
Claims
1. A method for equivalent simulation testing of sub-synchronous and super-synchronous oscillations of a dual-frequency coupled synchronous motor, characterized in that, including: (1) Construct an equivalent model of the oscillating voltage of a dual-frequency coupled synchronous motor, expressing the post-fault voltage as the sum of four terms, specifically including the steady-state quantity, the sub-synchronous frequency term, the super-synchronous frequency term, and the remainder term; (2) Based on the time-domain perturbation equation of the motor stator voltage, construct a sub- and super-synchronous signal test circuit to simulate the electrical quantities during sub- and super-synchronous oscillations; (3) Select appropriate parameters to cause oscillations in the line, determine the series compensation ratio and resonance frequency, and the parameters include resistance, inductance, and capacitance; (4) Obtain or directly adopt the voltages, phase angles, and power angles at the generator terminal and the grid terminal, and select an appropriate angular displacement increment amplitude to control the resonance power to meet the test requirements.
2. The oscillating equivalent simulation test method according to claim 1, characterized in that The expression of the sum of the four terms in step 1 is: Steady-state quantity: e a0 = u a0 = U m cos(ω0t + α u ); Sub-synchronous frequency term: Hyper-synchronous frequency term: Remainder: e a0 = Δu″ a = -(cos t·Δψ q + sin t·Δψ d ); Among them, U m represents the voltage amplitude, ω0 represents the rated frequency, α u represents the initial phase angle of the generator voltage under the condition that the direct axis of the rotor coincides exactly with the a-phase axis at t = 0, A represents the amplitude of the angular displacement increment, ω m represents the natural torsional vibration frequency, Δψ q and Δψ d represent the change in magnetic flux linkage in the dq0 coordinate system, e a0 、e ss 、e os represent the decomposed components of the equivalent parameters of the terminal voltage.
3. The oscillating equivalent simulation test method according to claim 1, characterized in that When constructing the sub- and super-synchronous signal test circuit in step 2, the equivalent parameter decomposition quantity of the terminal voltage is connected to the grid through an RLC equivalent circuit. For the perturbation voltage equation, let the remainder term be 0, and use the superposition principle to calculate the power frequency, sub-synchronous frequency, and super-synchronous frequency components respectively, and finally combine them to obtain the full voltage current quantity.
4. The oscillating equivalent simulation test method according to claim 1, wherein When selecting appropriate parameters in Step 3 to cause the line to oscillate, when the line series compensation degree and the natural torsional vibration frequency satisfy the relationship K = (1 - ω m / ω0) 2 , sub-synchronous resonance occurs in the system, and sub-synchronous and super-synchronous frequencies always appear in pairs, and the sum of the two is twice the power frequency, satisfying the relationship ω m = (ω os - ω ss / 2, where K represents the line series compensation degree, ω m represents the natural torsional vibration frequency, ω ss represents the sub-synchronous frequency, and ω os represents the super-synchronous frequency.
5. The oscillating equivalent simulation test method according to claim 1, characterized in that The formula for the resonant power described in Step 4 is P ss = P ssm {1 + cos[2(ω0 - ω m )t + 2α u}, and the active oscillating power during actual measurement is the average value of the instantaneous value within one period. For periodic oscillation, this average value is a constant. For oscillatory divergence, the power amplitude is changed in a stepwise manner to detect the operating threshold of the broadband measurement device.
6. The oscillating equivalent simulation test method according to claim 1, wherein In step 4, an appropriate angular displacement increment amplitude is selected to control the resonance power to meet the test requirements, where the range of the angular displacement increment amplitude is 0 to π / 12, and the extreme does not exceed π / 6.
7. The oscillating equivalent simulation test method according to claim 1, wherein When obtaining the initial phase angles at the generator terminal and the grid terminal in step 4, the generator power angle can be first obtained according to the internal impedance of the generator, the loop current, the line power factor, and the voltage at the generator outlet terminal, and then the initial phase angle at the generator terminal can be obtained. For the initial phase angle at the grid terminal, only the line impedance angle needs to be considered additionally.
8. A sub- and super-synchronous oscillation equivalent simulation test system for a dual-frequency coupled synchronous motor, characterized in that including: A model establishment module for establishing an equivalent model of sub- and super-synchronous oscillations of a dual-frequency coupled synchronous motor; A circuit construction module for constructing a sub- and super-synchronous signal test circuit based on the time-domain perturbation equation of the motor stator voltage; A parameter selection module for selecting appropriate parameters to cause oscillations in the line; A power calculation and control module for calculating the instantaneous oscillation power according to the test circuit and selecting an appropriate angular displacement increment amplitude to control the sub-synchronous resonance power to meet the test requirements.
9. A computer device, characterized in that, including one or more processors, a memory, and one or more programs, where the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and when the program is executed by the processor, it implements the steps of a method for equivalent simulation test of sub- and super-synchronous oscillations of a dual-frequency coupled synchronous motor as described in any one of claims 1-7.
10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of a method for equivalent simulation test of sub- and super-synchronous oscillations of a dual-frequency coupled synchronous motor as described in any one of claims 1-7.