Power system control method, device and equipment based on commutation sequence and medium

Abstract

The invention belongs to the technical field of electric power system control, and particularly relates to an electric power system control method and device based on a commutation sequence, equipment and a medium. The method comprises the following steps: based on system operation parameters at a fault removal moment, calculating a system acceleration area and a maximum deceleration area by adopting an expansion equal area criterion when a phase sequence change measure is not adopted; judging whether the system is unstable or not based on the acceleration area and the maximum deceleration area of the system when the phase sequence changing measure is not taken; if the system is unstable, judging whether a boundary condition for improving the stability of the system by a commutation sequence is met or not; and if yes, taking a commutation measure, and if a preset single-machine image rotor angle is met, carrying out commutation sequence operation. Further judging whether the maximum net deceleration area of the system adopting the commutation sequence measure is greater than or equal to the acceleration area of the system without adopting the commutation sequence measure, and if so, determining that the system is stable; otherwise, performing multiple times of commutation sequence control until the system is stable. According to the method, the problem of power angle instability of the power system after large disturbance is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power system control, and in particular relates to a power system control method, device, equipment and medium based on phase switching sequence. Background Art

[0002] Stability control is one of the most concerned topics in AC systems. With the gradual expansion of power scale, the system structure and model are becoming increasingly complex, and the operation of power systems is becoming more flexible and changeable, which poses greater challenges to the stability control of power systems. Many destructive accidents in power systems are caused by the instability of the power angle of the generator under large disturbances, which is usually characterized by the change of the power angle in the range of 0 to 2π. The imbalance of electromagnetic power and mechanical power after large disturbances is the main cause of the destruction of transient stability of the system. For a long time, power systems have adopted many measures to improve the transient stability of the system, such as the rapid removal of faults and the application of automatic reclosing devices, the use of forced excitation, fast valve control, emergency cutting, etc. These measures have played a role in improving system stability under certain conditions, but they also sacrificed the integrity of the power grid. Summary of the invention

[0003] The purpose of the present invention is to provide a power system control method, device, equipment and medium based on phase switching sequence to solve the problem of power angle instability after a large disturbance in the existing power system and achieve the purpose of stable control.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] In a first aspect of the present invention, a method for controlling a power system based on a phase switching sequence is provided, comprising the following steps:

[0006] Obtain system operating parameters at the time of fault removal;

[0007] Based on the system operating parameters at the time of fault removal, the system acceleration area and maximum deceleration area when no phase-changing sequence measures are taken are calculated using the extended equal area criterion; based on the system acceleration area and maximum deceleration area when no phase-changing sequence measures are taken, it is determined whether the system is unstable; when the system is determined to be unstable, the boundary conditions for the phase-changing sequence to improve the system stability are calculated;

[0008] Based on the boundary conditions, it is determined whether to take commutation measures; when it is determined that commutation measures are taken, a commutation sequence operation is performed when a preset single-machine image rotor angle is met.

[0009] Furthermore, after the step of performing the phase switching sequence operation, the method further includes:

[0010] The maximum net deceleration area of ​​the system with phase-changing sequence measures is compared with the acceleration area of ​​the system without phase-changing sequence measures to determine whether the system is stable; when the system is stable after the phase-changing sequence, the phase-changing sequence ends; when the system is still unstable after the phase-changing sequence, multiple phase-changing sequence controls are performed to gradually increase the deceleration area until the system is stable.

[0011] Furthermore, based on the system operating parameters at the time of fault removal, the extended equal area criterion is used to calculate the system acceleration area and maximum deceleration area when no phase-changing sequence measures are taken, including:

[0012] System acceleration area A when no phase change sequence measures are taken acc :

[0013]

[0014] The maximum deceleration area of ​​the system when no phase change measures are taken A dec :

[0015]

[0016] In the formula, δ τ represents the rotor angle of the single machine image at the time of fault removal; δ0 represents the stable equilibrium point of the single machine image of the system before the fault; P m P is the equivalent mechanical power of a single machine image; eD It is expressed as the electromagnetic power equivalent to the image of a single machine in the fault; δ represents the rotor angle of a single machine; P C , P max , γ are constants, subscript D indicates during a fault, and subscript P indicates after the fault is cleared and before the phase change sequence; P eP is the power angle characteristic of the single-machine system after the fault is removed and before the phase change sequence; δ u represents the unstable equilibrium point of the single machine image after fault removal; δ P Indicates the stable equilibrium point of the single-machine image after fault removal.

[0017] Furthermore, the boundary conditions for improving the stability of the system by calculating the commutation sequence include:

[0018]

[0019] Among them, δ P represents the stable equilibrium point of the single machine image after fault removal; δ h It represents the single-machine image rotor angle when performing phase-changing sequence operation; γ is a constant, and the subscript P represents the period from fault removal to phase-changing sequence.

[0020] Furthermore, the maximum net deceleration area A′ of the system taking phase-change measures dec The calculation formula is:

[0021]

[0022] The maximum net deceleration area change △A when taking phase change measures dec The calculation formula is:

[0023]

[0024] Among them, A acc is the system acceleration area when no phase change sequence measures are taken: δ u represents the unstable equilibrium point of the single machine image after fault removal; δ h Indicates the single-machine image rotor angle during phase-changing sequence operation; P′ eP It indicates the power angle characteristic of the single machine system after the phase change sequence; P m is the equivalent mechanical power of a single machine image; δ represents the rotor angle of a single machine; P eP It is the power angle characteristic of the single machine system after the fault is removed and before the phase change sequence; P C , P max , γ are constants, and the subscript P represents the period from fault removal to commutation sequence.

[0025] Furthermore, in the step of performing the phase-changing sequence operation when the preset single-machine image rotor angle is met, when the preset single-machine image rotor angle is determined in the following manner, it is an optimal power system control method based on the phase-changing sequence:

[0026] The value of the single-machine image rotor angle satisfies the following conditions:

[0027] When the maximum net deceleration area change takes the maximum positive value after taking the phase-changing sequence measures, the net deceleration area increased by the system is the largest.

[0028] Furthermore, for the optimal power system control method based on the commutation sequence, the preset single-machine image rotor angle δ h is: h =5π / 6+γ P ; Among them, γ is a constant, and the subscript P represents the period from fault removal to phase switching.

[0029] In a second aspect of the present invention, there is provided a power system control device based on a phase switching sequence, comprising:

[0030] A data acquisition module, used to obtain system operating parameters at the time of fault removal;

[0031] A judgment module is used to calculate the system acceleration area and the maximum deceleration area when no phase-changing sequence measures are taken based on the system operating parameters at the time of fault removal by adopting the extended equal area criterion; based on the system acceleration area and the maximum deceleration area when no phase-changing sequence measures are taken, judge whether the system is unstable; when the system is judged to be unstable, calculate the boundary conditions for the phase-changing sequence to improve the stability of the system;

[0032] The phase-changing sequence module is used to determine whether to take phase-changing measures based on the boundary conditions; when it is determined that phase-changing measures are taken, a phase-changing sequence operation is performed when a preset single-machine image rotor angle is met.

[0033] According to a third aspect of the present invention, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-mentioned power system control method based on phase switching sequence when executing the computer program.

[0034] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores a computer program, and wherein the computer program implements the above-mentioned power system control method based on phase switching sequence when executed by a processor.

[0035] Compared with the prior art, the present invention has at least the following beneficial effects:

[0036] Based on the extended equal area criterion, the maximum net deceleration area change after taking phase-changing sequence measures and the mechanism of phase-changing sequence technology to improve the stability of multi-machine systems are given. Based on this, the boundary conditions for phase-changing sequence technology to improve the stability of multi-machine systems are clarified, ensuring the effectiveness of phase-changing sequence control.

[0037] According to the preset phase-changing sequence single-machine image rotor angle, the optimal control strategy of the phase-changing sequence technology is proposed, and the boundary conditions of the phase-changing sequence technology corresponding to the optimal control strategy to improve the stability of the multi-machine system are given, so that the total deceleration area of ​​the system after the phase-changing sequence is maximized and the phase-changing sequence effect is optimal. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0039] Figure 1 This is a flow chart of a power system control method based on phase switching sequence according to an embodiment of the present invention;

[0040] Figure 2 A schematic diagram of an execution process of a power system control method based on a phase switching sequence according to an embodiment of the present invention;

[0041] Figure 3 A flow chart of a power system control method based on phase switching sequence according to a preferred embodiment of the present invention;

[0042] Figure 4 It is a phase diagram and schematic diagram of the phase sequence technology in the prior art;

[0043] Figure 5 This is a schematic diagram of EEAC equivalent values ​​of an embodiment of the present invention;

[0044] Figure 6 This is an acceleration and deceleration area diagram before and after the phase change sequence according to an embodiment of the present invention;

[0045] Figure 7 This is a structural block diagram of a power system control device based on phase switching sequence according to an embodiment of the present invention;

[0046] Figure 8 The present invention is a structural block diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0047] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0048] The following detailed description is an exemplary description, which is intended to provide further detailed description of the present invention. Unless otherwise specified, all technical terms used in the present invention have the same meaning as those generally understood by those skilled in the art to which the present invention belongs. The terms used in the present invention are only for describing specific embodiments, and are not intended to limit the exemplary embodiments according to the present invention.

[0049] like Figure 4 As shown in the figure, the phase sequence exchange (PSE) technology is a new power system stability control technology. The phase sequence exchange device is pre-installed at the generator outlet or on the tie line. When the power system is about to become unstable and the power angle increases to the set threshold, the power electronic device is used to quickly switch the phase sequence. The generator side A, B, C phases are disconnected from the system side a, b, c phases and then connected to the system side c, a, b phases accordingly. The schematic diagram is shown in Figure 4 (d) and (e). At the moment of phase change, the original potential phasor does not undergo a sudden change. The label is changed to the system side label order Therefore, the power angle at the moment the commutation sequence ends is Figure 4 (b) δ h becomes Figure 4 (c) δ′ h , thereby reducing the power angle by 2π / 3 and achieving the purpose of stable control.

[0050] Example 1

[0051] like Figure 1 As shown, a power system control method based on phase switching sequence includes the following steps:

[0052] S1. Obtain system operating parameters at the time of fault removal.

[0053] S2. Based on the system operating parameters at the moment of fault removal, the extended equal area criterion is used to calculate the system acceleration area and the maximum deceleration area when no phase-changing sequence measures are taken; based on the system acceleration area and the maximum deceleration area when no phase-changing sequence measures are taken, it is determined whether the system is unstable; when the system is determined to be unstable, the boundary conditions for improving the stability of the system by the phase-changing sequence are calculated.

[0054] S3. Based on the boundary conditions, determine whether to take commutation measures; when it is determined that commutation measures are taken, perform commutation sequence operations when a preset single-machine image rotor angle is met.

[0055] S4: Compare the maximum net deceleration area of ​​the system with phase-changing sequence measures and the acceleration area of ​​the system without phase-changing sequence measures to determine whether the system is stable; when the system is stable after the phase-changing sequence, the phase-changing sequence ends; when the system is still unstable after the phase-changing sequence, perform multiple phase-changing sequence controls to gradually increase the deceleration area until the system is stable.

[0056] In step S2, based on the system operating parameters at the time of fault removal, the system acceleration area and the maximum deceleration area when no phase-changing sequence measures are taken are calculated using the extended equal area criterion, including:

[0057] System acceleration area when no phase change sequence measures are taken:

[0058]

[0059] The maximum deceleration area of ​​the system when no phase change sequence measures are taken:

[0060]

[0061] In the formula, δ τ represents the rotor angle of the single machine image at the time of fault removal; δ0 represents the stable equilibrium point of the single machine image of the system before the fault; P m P is the equivalent mechanical power of a single machine image; eD It is expressed as the electromagnetic power equivalent to the image of a single machine in the fault; δ represents the rotor angle of a single machine; P CD , P maxD , γ D are all constants, the subscript D indicates a fault; P eP It is the power angle characteristic of the single machine system after the fault is removed and before the phase change sequence; P CP , P maxP , γ P are all constants, and the subscript P represents the period from fault removal to phase switching sequence; δ u represents the unstable equilibrium point of the single machine image after fault removal; δ P Indicates the stable equilibrium point of the single-machine image after fault removal.

[0062] In step S2, the boundary conditions for improving the stability of the system by calculating the commutation sequence include:

[0063]

[0064] In the formula, δ P represents the stable equilibrium point of the single machine image after fault removal; δ h It represents the single-machine image rotor angle when performing phase-changing sequence operation, γ is a constant, and the subscript P represents the period from fault removal to phase-changing sequence.

[0065] In step S3, when the preset single-machine image rotor angle is met, in the step of performing the phase-changing sequence operation, when the preset single-machine image rotor angle is determined in the following manner, it is an optimal power system control method based on the phase-changing sequence:

[0066] The value of the single-machine image rotor angle satisfies the following conditions:

[0067] When the maximum net deceleration area change takes the maximum positive value after taking the phase-changing sequence measures, the net deceleration area increased by the system is the largest.

[0068] Preferably, for the optimal power system control method based on the phase switching sequence, the preset single-machine image rotor angle δ h is: h =5π / 6+γ P .

[0069] In step S4, the maximum net deceleration area of ​​the system taking the phase change sequence measure is calculated as A′ dec The formula is:

[0070]

[0071] The maximum net deceleration area change △A when taking phase change measures dec The calculation formula is:

[0072]

[0073] Among them, A acc is the system acceleration area when no phase change sequence measures are taken: δ u represents the unstable equilibrium point of the single machine image after fault removal; δ h Indicates the single-machine image rotor angle during phase-changing sequence operation; P′ eP It indicates the power angle characteristic of the single machine system after the phase change sequence; P m is the equivalent mechanical power of a single machine image; δ represents the rotor angle of a single machine; P eP It is the power angle characteristic of the single machine system after the fault is removed and before the phase change sequence; P C , P max , γ are constants, and the subscript P represents the period from fault removal to commutation sequence.

[0074] In an optional embodiment of the present invention, a commutation sequence control method based on the extended equal area criterion is also provided. Figure 2 and Figure 3 As shown, the following steps are included:

[0075] Step 1: Perform a complementary group inertia center-relative motion transformation on the multi-machine system, map the multi-machine disturbed trajectories and the corresponding generator power functions before and after the phase switching sequence to an equivalent two-machine system, and further map them to an equivalent single-machine infinite system, build a multi-machine equivalent single-machine infinite system model before and after the phase switching sequence, and obtain the power angle characteristic expressions during the fault, after the fault is removed to before the phase switching sequence, and after the phase switching sequence.

[0076] Among the existing transient stability analysis methods, the Extended Equal Area Criterion (EEAC) method uses the complementary group model aggregation technology to equate a multi-machine system to a dual-machine system, and then further equates it to a single-machine infinite system to obtain an analytical dynamic equation. Finally, the equal area rule is used to judge the stability of the system. The schematic diagram is shown in the figure. Figure 5 This method has been successfully applied in the engineering practice of power systems at home and abroad.

[0077] Step 1 specifically includes the following steps:

[0078] Step 11: Divide the generators into two groups, S and A.

[0079] Specifically, assuming that the instability mode of the multi-machine system is a two-group mode, the S group is the critical group, the A group is the remaining group, the deviation angle of each machine's disturbed trajectory from the relevant inertia center is a constant, and the two groups are replaced by equivalent inertia centers, then the angle center δ of the S group and the A group is S , δ A Respectively expressed as:

[0080]

[0081] In the formula, δ i , δ j are the rotor angles of the i-th and j-th generators respectively; M i 、M j are the inertia time constants of the i-th and j-th generators respectively;

[0082] The offset of each machine's rotor angle relative to the group's inertia center angle ξ i , j for:

[0083]

[0084] In the formula, ξ i , jare the offsets of the i-th and j-th generators relative to the center angle of inertia of the group to which they belong.

[0085] Step 12: Then strictly transform the two-machine system into an equivalent single-machine infinite system, then the single-machine rotor angle δ and the single-machine equivalent motion equation are expressed as formulas 3 and 4 respectively:

[0086] δ=δ S -δ A (3)

[0087]

[0088] Where, M is the inertia time constant of a single machine, M = M S M A / M T ;M T =M A +M S ; represents the double derivative of δ; P m , P e They are the equivalent mechanical power and electromagnetic power of a single machine image, respectively, so we have:

[0089]

[0090] Where P mi , P mj is the mechanical power of the i-th and j-th generators before the commutation sequence;

[0091]

[0092] In the formula, E i 、E k 、E j 、E l are the internal potentials of generators i, k, j, and l respectively; Y ik ,φ ik , Y jl ,φ jl , Y ij ,φ ij are the modulus and angle of the ikth, jlth, ijth elements in the admittance matrix contracted to the internal nodes of the generator, Y is the modulus, φ is the angle; ξ i , k , j , l P is the rotor angle of each machine i, k, j, l, relative to the center angle of inertia of the group to which it belongs. C , P max , γ, C, and D are the intermediate values ​​derived from the formula.

[0093] Assuming that the instability mode of the multi-machine system is an ideal two-group mode, the deviation angle ξ of the disturbed trajectory of each machine from the relevant inertia center is i , k , j , l is a constant, so the dominant image system degenerates into a classical single-machine infinite system, and the corresponding single-machine image electromagnetic power P e The curve is a line that moves upward C , and then translate the sine curve of γ to the right, that is, P in formula (5) C , P max , γ are constants.

[0094] Step 13: Calculate the power angle characteristic expression during the fault, after the fault is removed and before the phase switching sequence, and after the phase switching sequence.

[0095] Assume that the power angle characteristics of the single machine system during the fault, after the fault is removed and before the phase change sequence, and after the phase change sequence are P eD , P eP , P′ eP , so the corresponding power angle characteristic expression can be obtained from formula (5):

[0096]

[0097] P e is the equivalent electromagnetic power of a single machine image. The subscript P indicates after the fault is removed, and the subscript D indicates during the fault.

[0098] Assuming that the mechanical power of the generator remains unchanged before and after the phase change sequence, the single machine image power angle characteristic curve before and after the phase change sequence is drawn according to formula (7). Figure 6 The equivalent single-machine infinite system power angle characteristic curve P′ after the phase change sequence eP Equivalent to P before the phase change sequence eP It is shifted to the right by 2π / 3. When the system is about to become unstable, the rotor angle δ h ∈[π / 2+γ P ,π+γ P ], the phase sequence operation is carried out, at the moment of phase sequence change, the electromagnetic power changes from P eP The h point on the curve suddenly changes to P′ eP Point h' on the curve, then continue along P' eP Curve operation.

[0099] The present invention maps the disturbed trajectories of multiple machines before and after the phase switching sequence and the corresponding generator power functions to an equivalent two-machine system through the complementary group inertia center-relative motion transformation, and further maps them to the system model. Then, it is determined whether to perform the phase switching sequence based on the calculated acceleration area and the maximum deceleration area, and the control effect is accurate.

[0100] Step 2: Obtain the system operating parameters at the time of fault removal, calculate the system acceleration area and maximum deceleration area when no phase-changing measures are taken based on the extended equal-area criterion, and make a judgment on the system stability.

[0101] Step 21: Obtain system operating parameters at the time of fault removal.

[0102] The system operating parameters at the time of fault removal include the single-machine image rotor angle δ at the time of fault removal τ .

[0103] Step 22: Calculate the stable equilibrium point δ0 of the single-machine image of the system before the failure. Specifically:

[0104]

[0105] Where P C0 , P max0 , γ0 are the parameters of the single machine power angle characteristic curve before the fault, which can be calculated by formula (6). The subscript 0 represents the initial state before the fault.

[0106] Step 23: Calculate the rotor angle δ of the single machine according to the moment of fault removal τ Compared with the stable equilibrium point δ0 of the single-machine image of the system before the fault, calculate the system acceleration area A when no phase change sequence measures are taken acc .

[0107] Specifically, by Figure 6 It can be seen that when no phase change measures are taken, the system acceleration area A acc for

[0108]

[0109] In the above formula, δ τ represents the rotor angle of the single machine image at the time of fault removal; δ0 represents the stable equilibrium point of the single machine image of the system before the fault; P m P is the equivalent mechanical power of a single machine image; eD It is expressed as the electromagnetic power equivalent to the image of a single machine in the fault; δ represents the rotor angle of a single machine; P CD , P maxD , γ D Respectively represent the intermediate values ​​in the stage fault; P eP It is the power angle characteristic of the single machine system after the fault is removed and before the phase change sequence; P CP , P maxP , γ P They represent the intermediate values ​​after the stage fault removal; δ u represents the unstable equilibrium point of the single machine image after fault removal; δ P Indicates the stable equilibrium point of the single-machine image after fault removal.

[0110] Step 24: Calculate the stable equilibrium point δ of the single machine image after fault removal P and the unstable equilibrium point δ u Specific

[0111]

[0112] δ u =π-δ P +2γ P (11)

[0113] Step 25: Calculate the maximum deceleration area A of the system when no phase change measures are taken dec .

[0114] Specifically, by Figure 6 It can be seen that when no phase change measures are taken, the maximum deceleration area of ​​the system is A dec for:

[0115]

[0116] In the above formula, δ τ Indicates the rotor angle of a single machine at the moment of fault removal; δ u represents the unstable equilibrium point of the single machine image after fault removal; P eP It is the power angle characteristic of the single machine system after the fault is removed and before the phase change sequence; P m is the equivalent mechanical power of a single machine image; δ represents the rotor angle of a single machine; P CP , P maxP , γ P They represent the intermediate values ​​after the stage fault is removed. P Indicates the stable equilibrium point of the single-machine image after fault removal.

[0117] Step 26: Determine the system acceleration area A when no phase change sequence measures are taken acc Is it greater than the maximum deceleration area A of the system when no phase change measures are taken? dec , get the first judgment result. If the first judgment result is no, the system is stable and no phase-changing sequence operation is required; if the first judgment result is yes, the system is unstable, and then proceed to step 3: determine whether phase-changing sequence measures can be taken.

[0118] Step 3: Based on the extended equal area criterion, the maximum net deceleration area change after taking phase-changing sequence measures and the mechanism of phase-changing sequence technology to improve the stability of multi-machine systems are given; based on this, the boundary conditions for phase-changing sequence technology to improve system stability are analyzed, and the boundary conditions are used to determine whether phase-changing sequence measures can be taken.

[0119] Step 31: Based on the extended equal area criterion, the maximum net deceleration area change after taking phase-changing sequence measures and the mechanism of phase-changing sequence technology to improve the stability of the multi-machine system are given. Figure 6 It can be seen that if the rotor angle in the single machine image is δ h ∈[π / 2+γ P ,π+γ P ], the phase change sequence operation is carried out, and the maximum net deceleration area of ​​the system is A′ dec for:

[0120]

[0121] The maximum deceleration area of ​​the system when no phase change measures are taken A dec As shown in formula (12). Therefore, the maximum net deceleration area change ΔA after taking the phase change sequence measure dec for:

[0122]

[0123] Among them, P′ eP It is the power angle characteristic of the single machine system after the phase change sequence.

[0124] From formula (14), we can see that when ΔA dec <0, the system deceleration area is reduced after taking phase-change measures; when ΔA dec >0, the system deceleration area increases after taking phase-change sequence measures. It can be seen that without taking other measures, the necessary conditions for the system to stabilize only through one or more phase-change sequence controls are:

[0125] ΔA dec >0 (15)

[0126] Therefore, the mechanism by which the phase-changing sequence technology improves system stability is that the phase-changing sequence increases the deceleration area of ​​the system.

[0127] Step 32: Analyze the boundary conditions for improving system stability by using phase-changing sequence technology.

[0128] Substituting equation (14) into the necessary stability condition of equation (15), we can obtain:

[0129]

[0130] Substituting formula (16) into formula (10), we can get:

[0131]

[0132] In the formula, δ h It is the rotor angle of the single machine image of the phase change sequence.

[0133] Therefore, formula (17) is the boundary condition for improving system stability based on the phase-changing sequence technology based on the extended equal-area criterion. In other words, δ P After satisfying the condition of formula (17), ΔA decSatisfying formula (15), in a single machine image δ = δ h Only by changing the phase sequence can the transient stability of the system be improved.

[0134] Step 33: Determine whether phase-changing sequence measures can be taken based on boundary conditions.

[0135] If the first judgment result in the above step 2 is yes, this step continues to determine the stable equilibrium point δ of the single machine image after the fault is removed. P Whether the boundary condition of formula (17) is satisfied is used to obtain the second judgment result; if the second judgment result is no, no phase switching sequence measures are taken and the system becomes unstable; if the second judgment result indicates yes, proceed to step 4.

[0136] Step 4: Take phase sequence control measures

[0137] Specifically, the single-machine image rotor angle of the power system is continuously monitored. When the single-machine image rotor angle is δ h The phase change sequence operation is performed when h It is the rotor angle of the single machine image of the set commutation sequence.

[0138] Under the necessary stability condition of equation (15), ΔA dec The larger the ΔA is, the larger the net deceleration area increased by the phase change sequence, and the larger the total deceleration area after the phase change sequence, the more conducive to system stability. From formula (14), we can see that ΔA dec The size of P m , P CP , P maxP , γ P , δ h The value of P is determined by the system operating condition when the fault is removed and the system operating condition remains unchanged. m , P CP , P maxP , γ P unchanged, at this time, ΔA dec The size of the phase change sequence is determined by the rotor angle δ h Therefore, ΔA dec The corresponding δ at the maximum h , which is the optimal control strategy for the phase change sequence.

[0139] ΔA dec About the Rotor Angle δ of the Single Machine Image of the Phase Commutation Sequence h The derivative of is:

[0140]

[0141] To obtain ΔA dec Stationary point, let equation (18) equal to 0 and δ h ∈[π / 2+γ P ,π+γ P ], so we get:

[0142]

[0143] It can be determined that: h =5π / 6+γ P When ΔA dec is the maximum positive value, the increased net deceleration area is the largest, and its value is Thus, the optimal phase-changing sequence is achieved. That is, the optimal control strategy is δ h =5π / 6+γ P Changing the phase sequence at the same time can achieve the optimal effect of phase changing sequence.

[0144] Substituting equation (19) into equation (17) we can get the optimal control strategy δ h =5π / 6+γ P The boundary condition for improving system stability by the phase-changing sequence technology corresponding to step 3 is:

[0145] δ P <0.31π+γ P (20)

[0146] Step 5: Determine whether the system is stable after the phase change sequence

[0147] The maximum net deceleration area A′ of the system when the phase-changing sequence measure is taken is calculated by formula (13): dec . Determine the maximum net deceleration area A' of the system when taking phase-change sequence measures dec Is it greater than or equal to the system acceleration area A when no phase change measures are taken? acc , and obtain the third judgment result. If the third judgment result indicates yes, then the phase change sequence can stabilize the system, and the phase change sequence ends; if the third judgment result indicates no, then the system is still unstable after the phase change sequence, and multiple phase change sequence controls can be performed, gradually increasing the deceleration area until the system is stable, that is, jumping to step 4, repeating the phase change sequence operation until the third judgment result is yes and the power system is stable.

[0148] Example 2

[0149] like Figure 7 As shown, based on the same inventive concept as the above embodiment, the present invention further provides a power system control device based on a phase switching sequence, comprising:

[0150] A data acquisition module, used to obtain system operating parameters at the time of fault removal;

[0151] A judgment module is used to calculate the system acceleration area and the maximum deceleration area when no phase-changing sequence measures are taken based on the system operating parameters at the time of fault removal by adopting the extended equal area criterion; based on the system acceleration area and the maximum deceleration area when no phase-changing sequence measures are taken, judge whether the system is unstable; when the system is judged to be unstable, calculate the boundary conditions for the phase-changing sequence to improve the stability of the system;

[0152] The phase-changing sequence module is used to determine whether to take phase-changing measures based on the boundary conditions; when it is determined that phase-changing measures are taken, a phase-changing sequence operation is performed when a preset single-machine image rotor angle is met.

[0153] Example 3

[0154] like Figure 8 As shown, the present invention also provides an electronic device 100 for implementing a power system control method based on a phase switching sequence according to the above embodiment;

[0155] The electronic device 100 includes a memory 101 , at least one processor 102 , a computer program 103 stored in the memory 101 and executable on the at least one processor 102 , and at least one communication bus 104 .

[0156] The memory 101 can be used to store a computer program 103 , and the processor 102 implements the steps of a power system control method based on a phase switching sequence in Example 1 by running or executing the computer program stored in the memory 101 and calling the data stored in the memory 101 .

[0157] The memory 101 may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area may store data (such as audio data) created according to the use of the electronic device 100, etc. In addition, the memory 101 may include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other non-volatile solid-state storage devices.

[0158] At least one processor 102 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor 102 may be a microprocessor or any conventional processor, etc. The processor 102 is the control center of the electronic device 100, and uses various interfaces and lines to connect various parts of the entire electronic device 100.

[0159] The memory 101 in the electronic device 100 stores a plurality of instructions to implement a power system control method based on a phase switching sequence, and the processor 102 can execute the plurality of instructions to implement:

[0160] Obtain system operating parameters at the time of fault removal;

[0161] Based on the system operating parameters at the time of fault removal, the system acceleration area and maximum deceleration area when no phase-changing sequence measures are taken are calculated using the extended equal area criterion; based on the system acceleration area and maximum deceleration area when no phase-changing sequence measures are taken, it is determined whether the system is unstable; when the system is determined to be unstable, the boundary conditions for the phase-changing sequence to improve the system stability are calculated;

[0162] Based on the boundary conditions, it is determined whether to take commutation measures; when it is determined that commutation measures are taken, a commutation sequence operation is performed when a preset single-machine image rotor angle is met.

[0163] Example 4

[0164] If the module / unit integrated in the electronic device 100 is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. Computer-readable media may include: any entity or device capable of carrying computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory and read-only memory (ROM, Read-Only Memory).

[0165] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0166] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks 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 processes in the flowchart and / or block diagram. 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.

[0167] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0168] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0169] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant 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 covered within the scope of protection of the claims of the present invention.

Claims

1. A power system control method based on phase switching sequence, characterized in that: The following steps are involved: Obtain system operating parameters at the time of fault removal; Based on the system operating parameters at the time of fault removal, the extended equal area criterion is used to calculate the system acceleration area and maximum deceleration area when no phase-changing sequence measures are taken; Based on the acceleration area and maximum deceleration area of ​​the system when no phase-changing sequence measures are taken, determine whether the system is unstable; when the system is determined to be unstable, calculate the boundary conditions for the phase-changing sequence to improve the system stability; Based on the boundary conditions, it is determined whether to take commutation measures; when it is determined that commutation measures are taken, a commutation sequence operation is performed when a preset single-machine image rotor angle is met.

2. The power system control method based on phase switching sequence according to claim 1, characterized in that: After the step of performing the phase change sequence operation, it also includes: The maximum net deceleration area of ​​the system with phase-changing sequence measures is compared with the acceleration area of ​​the system without phase-changing sequence measures to determine whether the system is stable; when the system is stable after the phase-changing sequence, the phase-changing sequence ends; when the system is still unstable after the phase-changing sequence, multiple phase-changing sequence controls are performed to gradually increase the deceleration area until the system is stable.

3. The power system control method based on phase switching sequence according to claim 1, characterized in that: Based on the system operating parameters at the time of fault removal, the extended equal area criterion is used to calculate the system acceleration area and maximum deceleration area when no phase-changing sequence measures are taken, including: System acceleration area A when no phase change sequence measures are taken acc : The maximum deceleration area of ​​the system when no phase change measures are taken A dec : In the formula, δ τ represents the rotor angle of the single machine image at the time of fault removal; δ0 represents the stable equilibrium point of the single machine image of the system before the fault; P m P is the equivalent mechanical power of a single machine image; eD It is expressed as the electromagnetic power equivalent to the image of a single machine in the fault; δ represents the rotor angle of a single machine; P C , P max , γ are constants, subscript D indicates during a fault, and subscript P indicates after the fault is cleared and before the phase change sequence; P eP is the power angle characteristic of the single-machine system after the fault is removed and before the phase change sequence; δ u represents the unstable equilibrium point of the single machine image after fault removal; δ P Indicates the stable equilibrium point of the single-machine image after fault removal.

4. The power system control method based on phase switching sequence according to claim 1, characterized in that: Calculate the commutation sequence to improve the boundary conditions of the system stability, including: Among them, δ P represents the stable equilibrium point of the single machine image after fault removal; δ h It represents the single-machine image rotor angle when performing phase-changing sequence operation; γ is a constant, and the subscript P represents the period from fault removal to phase-changing sequence.

5. The power system control method based on phase switching sequence according to claim 2, characterized in that: The maximum net deceleration area A of the system taking phase-change sequence measures d ' ec The calculation formula is: The maximum net deceleration area change △A when taking phase change measures dec The calculation formula is: Among them, A acc is the system acceleration area when no phase change sequence measures are taken: δ u represents the unstable equilibrium point of the single machine image after fault removal; δ h Indicates the single-machine image rotor angle during phase-changing sequence operation; P e ' P It indicates the power angle characteristic of the single machine system after the phase change sequence; P m is the equivalent mechanical power of a single machine image; δ represents the rotor angle of a single machine; P eP It is the power angle characteristic of the single machine system after the fault is removed and before the phase change sequence; P C , P max , γ are constants, and the subscript P represents the period from fault removal to commutation sequence.

6. The power system control method based on commutation sequence according to claim 1, characterized in that: In the step of performing the phase switching sequence operation when the preset single-machine image rotor angle is met, the preset single-machine image rotor angle is determined as follows to be the optimal power system control method based on the phase switching sequence: The value of the single-machine image rotor angle satisfies the following conditions: When the maximum net deceleration area change takes the maximum positive value after taking the phase-changing sequence measures, the net deceleration area increased by the system is the largest.

7. The optimal power system control method based on commutation sequence according to claim 6, characterized in that: Preset single-machine image rotor angle δ h for: Where γ is a constant, and the subscript P represents the period from fault removal to commutation sequence.

8. A power system control device based on phase switching sequence, characterized in that: include: A data acquisition module, used to obtain system operating parameters at the time of fault removal; A judgment module is used to calculate the system acceleration area and the maximum deceleration area when no phase-changing sequence measures are taken based on the system operation parameters at the time of fault removal by adopting the extended equal area criterion; Based on the acceleration area and maximum deceleration area of ​​the system when no phase-changing sequence measures are taken, determine whether the system is unstable; when the system is determined to be unstable, calculate the boundary conditions for the phase-changing sequence to improve the system stability; The phase-changing sequence module is used to determine whether to take phase-changing measures based on the boundary conditions; when it is determined that phase-changing measures are taken, a phase-changing sequence operation is performed when a preset single-machine image rotor angle is met.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, a power system control method based on phase switching sequence as described in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, a power system control method based on phase switching sequence as described in any one of claims 1 to 7 is implemented.

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