Method for determining small interference stability damping ratio margin sensitivity of power system

Abstract

The invention provides a power system small interference stability damping ratio margin sensitivity determination method, which comprises the following steps: firstly, considering the change of a load and generation power increase mode, and constructing a power system small interference stability model containing the power increase mode; secondly, on the basis of a preset damping ratio threshold value, forming a small-interference stability dynamic performance boundary condition, and constructing a small-interference stability damping ratio margin index; then, deriving analysis sensitivity expression of the small interference stability damping ratio margin index on system operation parameters and a power increasing mode; and finally, providing a method for calculating the small interference damping ratio margin sensitivity. The method can be used for analyzing the influence of system operation parameters and power increasing modes on the small-interference stability damping ratio margin, searching for the most dangerous power increasing mode and formulating online and offline small-interference stability margin improvement strategies, is universal and easy to implement, and has high application value.

Description

Technical Field

[0001] The invention relates to the field of power system stability and control, and in particular to a method for determining the sensitivity of a small-disturbance stability damping ratio margin of a power system. Background Art

[0002] The small disturbance stability margin is an indicator that describes the relationship between the current high-stability operating state of the power system and the operating state that is about to become unstable due to small disturbances. The small disturbance stability margin indicator is widely used in small disturbance stability assessment, active power generation scheduling, etc. However, the national standard "Power System Safety and Stability Calculation Specification" requires that the power system should not only be stable under small disturbances, but also that the damping ratio should meet certain requirements. In this context, the small disturbance stability damping ratio margin indicator was proposed to describe the relationship between the current high-damping operating state of the power system and the weak damping operating state that is about to become.

[0003] The small disturbance stability damping ratio margin index is related to the current operating state, critical operating state and power growth mode of the system. In order to analyze the impact of the current operating state and power growth mode of the system on the small disturbance stability damping ratio margin, find the most dangerous power growth mode, and formulate a reasonable small disturbance stability margin improvement strategy, it is necessary to study the sensitivity of the small disturbance stability damping ratio margin. Existing research has carried out a lot of research work on the sensitivity calculation of the small disturbance stability margin and the calculation of the small disturbance stability damping ratio margin, but the research on the general analytical sensitivity expression of the small disturbance stability damping ratio margin to the system operating parameters (such as generator active power, node voltage, etc.) and power growth mode has not been found. Summary of the invention

[0004] The purpose of the present invention is to propose a universal method for determining the sensitivity of the small disturbance stability damping ratio margin of the power system by studying the influence of the small disturbance stability damping ratio margin on the system operating parameters and the power growth mode on the analytical sensitivity expression.

[0005] The objective of the present invention is achieved by the following technical solutions:

[0006] In a first aspect, the present invention provides a method for determining the sensitivity of a small disturbance stability damping ratio margin of a power system, comprising the following steps:

[0007] Step 1: Considering the changes in the load and power generation growth patterns, a small disturbance stability model of the power system with explicit power growth patterns is constructed;

[0008] Step 1.1: When the operation mode of the power system changes, the expressions for the changes in load and power generation are:

[0009] S=S N +μB (1)

[0010] In formula (1), S N and S represent the power column vectors at the current operating point and any operating point respectively; μ is the step size; B is the column vector describing the load and power generation growth mode, which is determined by the short-term power forecast and power generation scheduling plan; S N , the elements in S and B include the generator active power, load active power and load reactive power;

[0011] Step 1.2: Design and the differential-algebraic equations of the power system for load and generation growth are expressed as:

[0012]

[0013]

[0014] In equations (2) and (3), x and m are the state vector and non-state vector respectively; represents the derivative of x with respect to time t; and They respectively describe the differential relationship and algebraic relationship in the power system, and equation (3) contains equation (1);

[0015] Equations (2) and (3) explicitly include the load and generation growth mode B, and also include the differential-algebraic relationship of the synchronous generator, synchronous condenser, excitation system, speed control system and power system stabilizer, as well as the system network equations;

[0016] Step 1.3: Order The superscript T represents the matrix transpose, and equations (2) and (3) are concisely expressed as:

[0017]

[0018] Step 1.4: Under the given parameter μ and power growth mode B, linearize equation (4) and eliminate the non-state vector m, and obtain the state space equation The state matrix Δ indicates a small change;

[0019] Step 1.5: Let λ = σ ± jω be a pair of complex eigenvalues ​​of the state matrix A, and obtain the corresponding damping ratio as:

[0020]

[0021] In formula (5), σ is used to judge the small disturbance stability of the system, and ζ describes the dynamic performance of the system;

[0022] Step 2: Based on the preset damping ratio threshold, the small disturbance stability dynamic performance boundary condition is formed, and the small disturbance stability damping ratio margin index is constructed;

[0023] The critical operating point is defined as: along a given power growth mode B, as μ increases, the current operating point of the power system will change, and the critical mode corresponding to the minimum damping ratio on the complex plane will eventually reach the preset damping ratio line ζ M , the critical mode will become a weak damping ratio mode when it passes through the damping ratio line. The operating point in this case is defined as the critical operating point;

[0024] Step 2.1: Assume that the equation that must be satisfied at any critical operating point on the dynamic performance boundary is:

[0025] F(x C ,m C ,μ C ,B)=0 (6)

[0026] A C U Re,C -σ M,C U Re,C +ω M,C U Im,C =0 (7)

[0027] A C U Im,C -σ M,C U Im,C -ω M,C U Re,C =0 (8)

[0028]

[0029]

[0030]

[0031] In equations (6) to (11), the subscript C represents the critical operating point; σ M and ω M are the eigenvalues ​​λ corresponding to the minimum damping ratio M The real and imaginary parts of U Re and U Im The eigenvalues ​​λ are M The real and imaginary parts of the right eigenvector of ;

[0032] Step 2.2: Set the small disturbance stability damping ratio margin index is the distance from the current operating point to the dynamic performance boundary, that is,

[0033]

[0034] In formula (12), P L,C and P L,Nare the load active power column vectors of the current operating point and the critical operating point respectively; ||·|| 2 represents the 2-norm;

[0035] Considering the relationship between the current operating point and the critical operating point and the static voltage characteristics of the load, P is obtained. L,N and P L,C The i-th element P Li,N and P Li,C The expressions are:

[0036] P Li,N =S Li,N (V i,N / V i,0 ) a (13)

[0037] P Li,C =(S Li,N +μ C B Li,P )(V i,C / V i,0 ) a (14)

[0038] In formula (13)-formula (14), S Li,N For S N The elements in B describe the active load of node i at the current operating point; Li,P is an element in B, describing the load active growth mode of node i; V i,N and V i,C are the voltage amplitudes of node i at the current operating point and the critical operating point respectively; V i,0 is the rated voltage of node i; a is the exponential coefficient of active load;

[0039] Step 3: Based on the constructed power system small disturbance stability model with explicit power growth mode and the small disturbance stability damping ratio margin index, the analytical sensitivity expression of the small disturbance stability damping ratio margin index to the system operating parameters and power growth mode is given;

[0040] Step 3.1: The operating parameter K includes the generator active power and node voltage amplitude at the current operating point. The analytical sensitivity expression of the small disturbance stability damping ratio margin index to the system operating parameter K is:

[0041]

[0042]

[0043]

[0044] In formula (15)-(17), Kj is the jth element in vector K; V xi,C and V yi,C V i,C The real and imaginary parts of V xi,N and V yi,N V i,N The real and imaginary parts of

[0045] Step 3.2: Assume that the analytical sensitivity expression of the small disturbance stability damping ratio margin index to power growth mode B is:

[0046]

[0047]

[0048] In formula (18)-formula (19), B j is the jth element in the power growth mode vector B;

[0049] Step 3.3: In equations (15) to (19), and It is related to the inverse Jacobian matrix of the power flow equation at the current operating point; It is related to the way generation and load are growing;

[0050] Get V xi,C , V yi,C and μ C The analytical sensitivity expression of is:

[0051] Step 3.3.1: Let κ = [K T B T ] T , abbreviate equation (6) to equation (11) as:

[0052]

[0053] In formula (20), And the number of equations in (20) is consistent with the number of elements in the vector y;

[0054] Step 3.3.2: Let κ i is the i-th element in the vector κ. Using the implicit function derivation rule, we can obtain the analytical sensitivity expression of the vector y:

[0055]

[0056] In formula (21), is a column vector, and the specific expression is:

[0057]

[0058] In formula (21), is the Jacobian matrix of formula (20), and the specific expression is:

[0059]

[0060] In formula (23), I is the identity matrix, C, R and W are sub-matrices;

[0061] Step 3.3.3: Let e i is the i-th element of vector e, R i and W i are the i-th column vectors of matrices R and W respectively, and we get C, R i and W i The expression is:

[0062]

[0063] In formula (23), D, T and M are column vectors, and the expression is:

[0064]

[0065] In formula (23), the expressions of Y and Z are:

[0066]

[0067] Step 4: Calculate and output the sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode;

[0068] Step 4.1: Input power system parameters, perform power flow calculation at the current operating point, and determine V xi,N and V yi,N , and calculate and

[0069] Step 4.2: Use Newton's method to solve equations (6)-(11) or (20), determine the value of each element in vector y, and save the inverse Jacobian matrix formed by the last iteration.

[0070] Step 4.3: Use equations (12)-(14) to calculate the small disturbance stability damping ratio margin index, and use equation (22) to calculate Calculate using formula (21) No need to calculate For all elements in and

[0071] Step 4.4: Calculate equations (15)-(17) and (18)-(19) to obtain the sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode.

[0072] In a second aspect, the present invention provides a system for determining the sensitivity of a small disturbance stability damping ratio margin of a power system, comprising:

[0073] The power system small disturbance stability model construction module is used to construct a power system small disturbance stability model with explicit power growth mode under the condition of considering the changes in load and power generation growth mode;

[0074] A small disturbance stability damping ratio margin index construction module, used to form a small disturbance stability dynamic performance boundary condition based on a preset damping ratio threshold, and to construct a small disturbance stability damping ratio margin index;

[0075] The module for providing analytical sensitivity expressions is used to provide analytical sensitivity expressions of the small disturbance stability damping ratio margin index to system operating parameters and power growth mode based on the constructed power system small disturbance stability model with explicit power growth mode and the small disturbance stability damping ratio margin index;

[0076] A calculation and output module is used to calculate and output the sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode;

[0077] The power system small disturbance stability model construction module is connected to the small disturbance stability damping ratio margin index construction module, the small disturbance stability damping ratio margin index construction module is connected to the analytical sensitivity expression given module, and the analytical sensitivity expression given module is connected to the calculation and output module, so as to implement the power system small disturbance stability damping ratio margin sensitivity determination method described in claim 1.

[0078] In a third aspect, the present invention provides a method for assisting power system operation control, comprising:

[0079] The sensitivity of the power system small disturbance stability damping ratio margin to the system operating parameters and the power growth mode is determined by using the power system small disturbance stability damping ratio margin sensitivity determination method.

[0080] According to the obtained sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode, the influence of the power system operating parameters and power growth mode on the small disturbance stability damping ratio margin is determined, the most dangerous power growth mode is found, and a strategy for improving the small disturbance stability damping ratio margin is formulated, providing a reference for the operation and regulation of the power system.

[0081] In a fourth aspect, the present invention provides a system for assisting in the operation and regulation of a power system, including the system for determining the sensitivity of the small disturbance stability damping ratio margin of the power system;

[0082] The sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode is obtained by determining the system sensitivity of the small disturbance stability damping ratio margin of the power system;

[0083] According to the sensitivity of the obtained small disturbance stability damping ratio margin to the system operating parameters and power growth mode, the power system operation control is assisted.

[0084] In a fifth aspect, the present invention provides a computer device, comprising a memory, a processor and a computer program stored on the memory, characterized in that the processor executes the computer program to implement the method for determining the sensitivity of the damping ratio margin of small disturbance stability of the power system as described.

[0085] In a sixth aspect, the present invention provides a computer-readable storage medium having a computer program / instruction stored thereon, which, when executed by a processor, implements the method for determining the sensitivity of the damping ratio margin of small disturbance stability of a power system as described above.

[0086] In a seventh aspect, the present invention provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the method for determining the sensitivity of the damping ratio margin of small disturbance stability of a power system as described.

[0087] Compared with the prior art, the present invention has outstanding substantive features and significant progress, specifically:

[0088] 1. The present invention firstly constructs a small disturbance stability model of the power system with explicit power growth mode under the condition of considering the changes in the load and power generation growth mode; secondly, based on the preset damping ratio threshold, forms the small disturbance stability dynamic performance boundary condition, and constructs the small disturbance stability damping ratio margin index; then, derives the analytical sensitivity expression of the small disturbance stability damping ratio margin index to the system operating parameters and the power growth mode; finally, provides a method for calculating the sensitivity of the small disturbance damping ratio margin; the method is universal and easy to implement.

[0089] 2. The sensitivity obtained by the sensitivity determination method of the present invention can be used to analyze the influence of system operating parameters and power growth mode on small disturbance stability damping ratio margin, find the most dangerous power growth mode, and formulate online and offline small disturbance stability margin improvement strategies, which has high application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] Figure 1 This is a 24-point power system diagram for 8 machines. DETAILED DESCRIPTION

[0091] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0092] Example 1

[0093] This embodiment provides a method for determining the sensitivity of the damping ratio margin of small disturbance stability of a power system, and the implementation steps are as follows:

[0094] Step 1: Considering the changes in the load and power generation growth patterns, a small disturbance stability model of the power system with explicit power growth patterns is constructed.

[0095] The construction method of the small disturbance stability model of the power system with explicit power growth mode includes:

[0096] Step 1.1: When the operation mode of the power system changes, the expressions for the changes in load and power generation are:

[0097] S=S N +μB (1)

[0098] In formula (1), S N and S represent the power column vectors at the current operating point and any operating point respectively; μ is the step size; B is the column vector describing the load and power generation growth mode, which can be determined by the short-term power forecast and power generation scheduling plan; S N , the elements in S and B include the generator active power, load active power and load reactive power.

[0099] Step 1.2: Design and the differential-algebraic equations of the power system for load and generation growth are expressed as:

[0100]

[0101]

[0102] In equations (2) and (3), x and m are the state vector and non-state vector respectively; represents the derivative of x with respect to time t; and They respectively describe the differential relationship and algebraic relationship in the power system, and equation (3) contains equation (1);

[0103] Equations (2) and (3) explicitly include the load and generation growth mode B, and also include the differential-algebraic relationship of the synchronous generator, synchronous phase regulator, excitation system, speed control system and power system stabilizer, as well as the system network equation.

[0104] Step 1.3: Order The superscript T represents the matrix transpose, and equations (2) and (3) are concisely expressed as:

[0105]

[0106] Step 1.4: Under the given parameter μ and power growth mode B, linearize equation (4) and eliminate the non-state vector m, and obtain the state space equation The state matrix Δ indicates a small change.

[0107] Step 1.5: Let λ = σ ± jω be a pair of complex eigenvalues ​​of the state matrix A, and obtain the corresponding damping ratio as:

[0108]

[0109] In formula (5), σ can be used to judge the small disturbance stability of the system, and ζ describes the dynamic performance of the system.

[0110] Step 2: Based on the preset damping ratio threshold, the small disturbance stability dynamic performance boundary condition is formed, and the small disturbance stability damping ratio margin index is constructed.

[0111] Definition of critical operating point: Along a given power growth pattern B, as μ increases, the current operating point of the power system will change, and the critical mode corresponding to the minimum damping ratio on the complex plane will eventually reach the preset damping ratio line ζ M , the critical mode will become a weak damping ratio mode when it passes through the damping ratio line. In this case, the operating point is defined as the critical operating point.

[0112] The construction method of the small disturbance stability damping ratio margin index includes:

[0113] Step 2.1: Along each power growth mode, a critical operating point can be obtained. The dynamic performance boundary is composed of all critical operating points in the multidimensional parameter space, where each critical operating point must satisfy both the steady-state equation and the minimum damping ratio requirements. Therefore, the equation that any critical operating point on the dynamic performance boundary must satisfy is:

[0114] F(x C ,m C ,μ C ,B)=0 (6)

[0115] A C URe,C -σ M,C U Re,C +ω M,C U Im,C =0 (7)

[0116] A C U Im,C -σ M,C U Im,C -ω M,C U Re,C =0 (8)

[0117]

[0118]

[0119]

[0120] In equations (6) to (11), the subscript C represents the critical operating point; σ M and ω M are the eigenvalues ​​λ corresponding to the minimum damping ratio M The real and imaginary parts of U Re and U Im The eigenvalues ​​λ are M The real and imaginary parts of the right eigenvector of .

[0121] Step 2.2: Set the small disturbance stability damping ratio margin index is the distance from the current operating point to the dynamic performance boundary, that is,

[0122]

[0123] In formula (12), P L,C and P L,N are the current operating point and the critical operating point P L,N The load active power column vector of point; ||·|| 2 represents the 2-norm;

[0124] Considering the relationship between the current operating point and the critical operating point and the static voltage characteristics of the load, P is obtained. L,N and P L,C The i-th element P Li,N and P Li,C The expression is:

[0125] P Li,N =S Li,N (V i,N / V i,0 ) a (13)

[0126] P Li,C =(SLi,N +μ C B Li,P )(V i,C / V i,0 ) a (14)

[0127] In formula (13)-formula (14), S Li,N For S N The elements in B describe the active load of node i at the current operating point; Li,P is an element in B, describing the load active growth mode of node i; V i,N and V i,C are the voltage amplitudes of node i at the current operating point and the critical operating point respectively; V i,0 is the rated voltage of node i; a is the exponential coefficient of active load.

[0128] Step 3: Based on the constructed power system small disturbance stability model with explicit power growth mode and the small disturbance stability damping ratio margin index, the analytical sensitivity expression of the small disturbance stability damping ratio margin index to the system operating parameters and power growth mode is given.

[0129] The method to obtain the analytical sensitivity expression of the small disturbance stability damping ratio margin index is:

[0130] Step 3.1: The analytical sensitivity of the small disturbance stability damping ratio margin index to the system operating parameter K (generator active power and node voltage amplitude at the current operating point) is expressed as:

[0131]

[0132]

[0133]

[0134] In formula (15)-(17), K j is the jth element in vector K; V xi,C and V yi,C V i,C The real and imaginary parts of V xi,N and V yi,N V i,N The real and imaginary parts of .

[0135] Step 3.2: Assume that the analytical sensitivity of the small disturbance stability damping ratio margin index to the power growth mode B is expressed as:

[0136]

[0137]

[0138] In formula (18)-formula (19), B j is the jth element in vector B.

[0139] Step 3.3: In equations (15) to (19), and It is related to the inverse Jacobian matrix of the power flow equation at the current operating point; It is related to the way generation and load are growing;

[0140] Get V xi,C , V yi,C and μ C The analytical sensitivity expression of is:

[0141] Step 3.3.1: Let κ = [K T B T ] T , abbreviate equation (6) to equation (11) as:

[0142]

[0143] In formula (20), And the number of equations in formula (20) is consistent with the number of elements in vector y.

[0144] Step 3.3.2: Since V xi,C and V yi,C Belongs to vector m C The element in m C and μ C are all included in the vector y, so with the help of vector y, the analytical sensitivity expression is obtained through equation (20). Let κ i is the i-th element in the vector κ. Using the implicit function derivation rule, we can obtain the analytical sensitivity expression of the vector y: for:

[0145]

[0146] In formula (21), is a column vector, and the specific expression is

[0147]

[0148] In formula (21), is the Jacobian matrix of formula (20), and the specific expression is

[0149]

[0150] In formula (23), I is the identity matrix, C, R and W are sub-matrices.

[0151] Step 3.3.3: Let e i is the i-th element of vector e, R i and W i are the i-th column vectors of matrices R and W respectively, and we get C, R i and W i The expression is:

[0152]

[0153] In formula (23), D, T and M are column vectors, and the expression is:

[0154]

[0155] In formula (23), the expressions of Y and Z are:

[0156]

[0157] Step 4: Calculate and output the sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode.

[0158] The fast calculation method of the small disturbance stability damping ratio margin sensitivity includes:

[0159] Step 4.1: Input power system parameters, perform power flow calculation at the current operating point, and determine V xi,N and V yi,N , and calculate and

[0160] Step 4.2: Use Newton's method to solve equations (6)-(11) or (20), determine the value of each element in vector y, and save the inverse Jacobian matrix formed by the last iteration.

[0161] Step 4.3: Use equations (12)-(14) to calculate the small disturbance stability damping ratio margin index, and use equation (22) to calculate Calculate using formula (21) No need to calculate For all elements in and

[0162] Step 4.4: Calculate equations (15)-(17) and (18)-(19) to obtain the sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode.

[0163] Simulation test analysis

[0164] This embodiment selects Figure 1The sensitivity calculation and analysis of the small disturbance stability damping ratio margin for the 8-machine 24-node power system shown in the figure are performed. Table 1 shows the sensitivity of the small disturbance stability damping ratio margin calculated by the method of the present invention and the perturbation method to the generator active power and node voltage at the current operating point, and Table 2 shows the sensitivity of the small disturbance stability damping ratio margin calculated by the method of the present invention and the perturbation method to the load active power growth mode. When the sensitivity is calculated by the perturbation method, the perturbation amount is 0.001pu.

[0165] Table 1 Sensitivity of small disturbance stability damping ratio margin to generator active power and node voltage at the current operating point

[0166]

[0167] Table 2 Sensitivity of small disturbance stability damping ratio margin to load active power growth mode

[0168]

[0169]

[0170] It can be seen from Table 1 and Table 2 that the signs of the sensitivities calculated by the method of the present invention and the perturbation method are consistent, and the order of magnitude is basically the same. Compared with the sensitivity of the damping ratio margin to the load active power growth mode in Table 2, the difference between the sensitivity of the damping ratio margin calculated by the method of the present invention to the generator active power and node voltage in Table 1 and the sensitivity calculated by the perturbation method is relatively large. This is because the nonlinearity between the damping ratio margin and the generator active power and node voltage at the current operating point is higher.

[0171] It can be seen from Table 1 that the sensitivity of the damping ratio margin to the active power of the generator is negative, and the sensitivity to the node voltage of the generator is positive. This shows that when the small disturbance stability damping ratio margin of the power system is enhanced, the active power of the generator at the current operating point can be reduced or the amplitude of the node voltage of the generator can be increased. In addition, compared with the sensitivity value of the damping ratio margin to the active power of the generator, the sensitivity value of the damping ratio margin to the node voltage of the generator is significantly larger. This means that when adjusting the system damping ratio margin, the effect of adjusting the node voltage of the generator is more obvious. It can be seen from Table 2 that the sensitivity of the damping ratio margin to the load active power growth mode is both positive and negative, which shows that when looking for the most dangerous load active power growth mode related to the minimum damping ratio margin, it can be achieved by reducing B L2,P , B L6,P , B L9,P , B L10,P , B L11,P and / or increase B L3,P , B L4,P , B L8,P , B L14,P , B L15,P to achieve.

[0172] The results in Table 1 and Table 2 show that the method of this embodiment can be used to calculate the sensitivity of the small disturbance stability damping ratio margin of the power system to the operating parameters and the power growth mode, analyze the influence of the system operating parameters and the power growth mode on the small disturbance stability damping ratio margin, find the most dangerous power growth mode, and formulate a strategy for improving the small disturbance stability damping ratio margin.

[0173] Based on the same inventive concept, the embodiment of the present application also provides a system for determining the sensitivity of the small disturbance stability damping ratio margin of the power system. The implementation scheme for solving the problem provided by the system is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more system embodiments for determining the sensitivity of the small disturbance stability damping ratio margin of the power system provided below can be referred to the limitations of the method above, and will not be repeated here.

[0174] In an exemplary embodiment, a system for determining a small disturbance stability damping ratio margin sensitivity of a power system is provided, comprising:

[0175] The power system small disturbance stability model construction module is used to construct a power system small disturbance stability model with explicit power growth mode under the condition of considering the changes in load and power generation growth mode;

[0176] A small disturbance stability damping ratio margin index construction module, used to form a small disturbance stability dynamic performance boundary condition based on a preset damping ratio threshold, and to construct a small disturbance stability damping ratio margin index;

[0177] The module for providing analytical sensitivity expressions is used to provide analytical sensitivity expressions of the small disturbance stability damping ratio margin index to system operating parameters and power growth mode based on the constructed power system small disturbance stability model with explicit power growth mode and the small disturbance stability damping ratio margin index;

[0178] A calculation and output module is used to calculate and output the sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode;

[0179] The power system small disturbance stability model construction module is connected to the small disturbance stability damping ratio margin index construction module, the small disturbance stability damping ratio margin index construction module is connected to the analytical sensitivity expression given module, and the analytical sensitivity expression given module is connected to the calculation and output module, so as to implement the power system small disturbance stability damping ratio margin sensitivity determination method described in Example 1.

[0180] In an exemplary embodiment, a method for controlling operation of an auxiliary power system is provided, characterized in that:

[0181] The method for determining the sensitivity of the small disturbance stability damping ratio margin of the power system as described in claim 1 is used to determine the sensitivity of the small disturbance stability damping ratio margin of the power system to the system operating parameters and the power growth mode;

[0182] According to the obtained sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode, the influence of the power system operating parameters and power growth mode on the small disturbance stability damping ratio margin is determined, the most dangerous power growth mode is found, and a strategy for improving the small disturbance stability damping ratio margin is formulated to provide a reference for the operation and regulation of the power system.

[0183] In an exemplary embodiment, a system for assisting power system operation regulation is provided, including the system for determining the sensitivity of the power system small disturbance stability damping ratio margin as described in Embodiment 2;

[0184] The sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode is obtained by determining the system sensitivity of the small disturbance stability damping ratio margin of the power system;

[0185] According to the sensitivity of the obtained small disturbance stability damping ratio margin to the system operating parameters and power growth mode, the power system operation control is assisted.

[0186] Each module in the above system can be implemented in whole or in part by software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute operations corresponding to each module above.

[0187] In an exemplary embodiment, a computer device is provided, which may be a terminal. The computer device further includes a processor, a memory, an input / output interface, a communication interface, a display unit, and an input device. The processor, the memory, and the input / output interface are connected via a system bus, and the communication interface, the display unit, and the input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be implemented through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, the steps of the method for determining the sensitivity of the damping ratio margin of small disturbance stability of the power system disclosed in Example 1 of the present application are implemented. The display unit of the computer device is used to form a visually visible picture, which may be a display screen, a projection device, or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device shell, or an external keyboard, touchpad or mouse.

[0188] Those skilled in the art will appreciate that a specific computer device may include more or fewer components, or combine certain components, or have a different arrangement of components.

[0189] In an exemplary embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for determining the small disturbance stability damping ratio margin sensitivity of the power system as disclosed in Example 1 of the present application are implemented.

[0190] In an exemplary embodiment, a computer program product is provided, including a computer program / instruction, which, when executed by a processor, implements the steps of the method for determining the small disturbance stability damping ratio margin sensitivity of a power system as disclosed in Example 1 of the present application.

[0191] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory or other media used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The processor involved in each embodiment provided in this application can be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, etc., but is not limited thereto.

[0192] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0193] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for determining the sensitivity of the damping ratio margin of small disturbance stability of a power system, characterized in that: The steps include: Step 1: Considering the changes in the load and power generation growth patterns, a small disturbance stability model of the power system with explicit power growth patterns is constructed; Step 1.1: When the operation mode of the power system changes, the expressions for the changes in load and power generation are: S=S N +μB (1) In formula (1), S N and S represent the power column vectors at the current operating point and any operating point respectively; μ is the step size; B is the column vector describing the load and power generation growth mode, which is determined by the short-term power forecast and power generation scheduling plan; S N , the elements in S and B include the generator active power, load active power and load reactive power; Step 1.2: Design and the differential-algebraic equations of the power system for load and generation growth are expressed as: In equations (2) and (3), x and m are the state vector and non-state vector respectively; represents the derivative of x with respect to time t; and They respectively describe the differential relationship and algebraic relationship in the power system, and equation (3) contains equation (1); Equations (2) and (3) explicitly include the load and generation growth mode B, and also include the differential-algebraic relationship of the synchronous generator, synchronous condenser, excitation system, speed control system and power system stabilizer, as well as the system network equations; Step 1.3: Order The superscript T represents the matrix transpose, and equations (2) and (3) are concisely expressed as: Step 1.4: Under the given parameter μ and power growth mode B, linearize equation (4) and eliminate the non-state vector m, and obtain the state space equation The state matrix Δ indicates a small change; Step 1.5: Let λ = σ ± jω be a pair of complex eigenvalues ​​of the state matrix A, and obtain the corresponding damping ratio as: In formula (5), σ is used to judge the small disturbance stability of the system, and ζ describes the dynamic performance of the system; Step 2: Based on the preset damping ratio threshold, the small disturbance stability dynamic performance boundary condition is formed, and the small disturbance stability damping ratio margin index is constructed; The critical operating point is defined as: along a given power growth mode B, as μ increases, the current operating point of the power system will change, and the critical mode corresponding to the minimum damping ratio on the complex plane will eventually reach the preset damping ratio line ζ M , the critical mode will become a weak damping ratio mode when it passes through the damping ratio line. The operating point in this case is defined as the critical operating point; Step 2.1: Assume that the equation that must be satisfied at any critical operating point on the dynamic performance boundary is: F(x C ,m C ,μ C ,B)=0 (6) AND C IN Re,C -σ M,C IN Re,C +ω M,C IN Im,C =0 (7) AND C IN Im,C -σ M,C IN Im,C -ω M,C IN Re,C =0 (8) In equations (6) to (11), the subscript C represents the critical operating point; σ M and ω M are the eigenvalues ​​λ corresponding to the minimum damping ratio M The real and imaginary parts of U Re and U Im The eigenvalues ​​λ are M The real and imaginary parts of the right eigenvector of ; Step 2.2: Set the small disturbance stability damping ratio margin index is the distance from the current operating point to the dynamic performance boundary, that is, In formula (12), P L,C and P L,N are the load active power column vectors of the current operating point and the critical operating point respectively; ||·||2 represents the 2-norm; Considering the relationship between the current operating point and the critical operating point and the static voltage characteristics of the load, P is obtained. L,N and P L,C The i-th element P Li,N and P Li,C The expressions are: P Li,N =S Li,N (V i,N / V i,0 ) a (13) P Li,C =(S Li,N +μ C B Li,P )(IN i,C / IN i,0 ) a (14) In formula (13)-formula (14), S Li,N For S N The elements in B describe the active load of node i at the current operating point; Li,P is an element in B, describing the load active growth mode of node i; V i,N and V i,C are the voltage amplitudes of node i at the current operating point and the critical operating point respectively; V i,0 is the rated voltage of node i; a is the exponential coefficient of active load; Step 3: Based on the constructed power system small disturbance stability model with explicit power growth mode and the small disturbance stability damping ratio margin index, the analytical sensitivity expression of the small disturbance stability damping ratio margin index to the system operating parameters and power growth mode is given; Step 3.1: The operating parameter K includes the generator active power and node voltage amplitude at the current operating point. The analytical sensitivity expression of the small disturbance stability damping ratio margin index to the system operating parameter K is: In formula (15)-(17), K j is the jth element in vector K; V xi,C and V yi,C V i,C The real and imaginary parts of V xi,N and V yi,N V i,N The real and imaginary parts of Step 3.2: Assume that the analytical sensitivity expression of the small disturbance stability damping ratio margin index to power growth mode B is: In formula (18)-formula (19), B j is the jth element in the power growth mode vector B; Step 3.3: In equations (15) to (19), and It is related to the inverse Jacobian matrix of the power flow equation at the current operating point; It is related to the way generation and load are growing; Get V xi,C , V yi,C and μ C The analytical sensitivity expression of is: Step 3.3.1: Let κ = [K T B T ] T , abbreviate equation (6) to equation (11) as: In formula (20), And the number of equations in (20) is consistent with the number of elements in the vector y; Step 3.3.2: Let κ i is the i-th element in the vector κ. Using the implicit function derivation rule, we can obtain the analytical sensitivity expression of the vector y: In formula (21), is a column vector, and the specific expression is: In formula (21), is the Jacobian matrix of formula (20), and the specific expression is: In formula (23), I is the identity matrix, C, R and W are sub-matrices; Step 3.3.3: Let e i is the i-th element of vector e, R i and W i are the i-th column vectors of matrices R and W respectively, and we get C, R i and W i The expression is: In formula (23), D, T and M are column vectors, and the expression is: In formula (23), the expressions of Y and Z are: Step 4: Calculate and output the sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode; Step 4.1: Input power system parameters, perform power flow calculation at the current operating point, and determine V xi,N and V yi,N , and calculate and Step 4.2: Use Newton's method to solve equations (6)-(11) or (20), determine the value of each element in vector y, and save the inverse Jacobian matrix formed by the last iteration. Step 4.3: Use equations (12)-(14) to calculate the small disturbance stability damping ratio margin index, and use equation (22) to calculate Calculate using formula (21) No need to calculate For all elements in and Step 4.4: Calculate equations (15)-(17) and (18)-(19) to obtain the sensitivity of the small disturbance stability damping ratio margin index to the system operating parameters and power growth mode.

2. A system for determining the sensitivity of the damping ratio margin of small disturbance stability of a power system, characterized in that: include: The power system small disturbance stability model construction module is used to construct a power system small disturbance stability model with explicit power growth mode under the condition of considering the changes in load and power generation growth mode; A small disturbance stability damping ratio margin index construction module, used to form a small disturbance stability dynamic performance boundary condition based on a preset damping ratio threshold, and to construct a small disturbance stability damping ratio margin index; The module for providing analytical sensitivity expressions is used to provide analytical sensitivity expressions of the small disturbance stability damping ratio margin index to system operating parameters and power growth mode based on the constructed power system small disturbance stability model with explicit power growth mode and the small disturbance stability damping ratio margin index; A calculation and output module is used to calculate and output the sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode; The power system small disturbance stability model construction module is connected to the small disturbance stability damping ratio margin index construction module, the small disturbance stability damping ratio margin index construction module is connected to the analytical sensitivity expression given module, and the analytical sensitivity expression given module is connected to the calculation and output module, so as to implement the power system small disturbance stability damping ratio margin sensitivity determination method described in claim 1.

3. A method for assisting power system operation control, characterized in that: The method for determining the sensitivity of the small disturbance stability damping ratio margin of the power system as described in claim 1 is used to determine the sensitivity of the small disturbance stability damping ratio margin of the power system to the system operating parameters and the power growth mode; According to the obtained sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode, the influence of the power system operating parameters and power growth mode on the small disturbance stability damping ratio margin is determined, the most dangerous power growth mode is found, and a strategy for improving the small disturbance stability damping ratio margin is formulated, providing a reference for the operation and regulation of the power system.

4. A system for assisting power system operation and regulation, characterized in that: The system for determining the sensitivity of the small disturbance stability damping ratio margin of the power system as claimed in claim 2; The sensitivity of the small disturbance stability damping ratio margin to the system operating parameters and power growth mode is obtained by determining the system sensitivity of the small disturbance stability damping ratio margin of the power system; According to the sensitivity of the obtained small disturbance stability damping ratio margin to the system operating parameters and power growth mode, the power system operation control is assisted.

5. A computer device comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the method for determining the small disturbance stability damping ratio margin sensitivity of a power system as claimed in claim 1.

6. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instruction is executed by a processor, the method for determining the small disturbance stability damping ratio margin sensitivity of a power system as claimed in claim 1 is implemented.

7. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the method for determining the small disturbance stability damping ratio margin sensitivity of a power system as claimed in claim 1 is implemented.

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