Coordinated optimization configuration method and device for improving transient voltage safety of regional power grid, equipment and storage medium

Abstract

The invention discloses a coordinated optimization configuration method, device and equipment for improving the transient voltage safety of a regional power grid, and a storage medium. The sum of the reconstruction cost of a network-forming inverter and the configuration cost of a static synchronous compensator is used as an objective function; dynamic models of a synchronous generator, a common load, an impact load, a network-following inverter of a new energy station, a network-constructing inverter and a static synchronous compensator are considered, and transient voltage safety constraints in the starting process of a three-phase short-circuit fault and the impact load are considered. In order to solve the problem that the current resistance level of a power electronic device in the grid-forming type inverter is too low, a current limiting constraint is set for the grid-forming type inverter, a polynomial interpolation function is obtained through a Lagrange interpolation method to approximate the current limiting constraint, and the situation that a large number of 0-1 variables need to be introduced into a model when a piecewise function is adopted is avoided. Therefore, the calculation efficiency of model solution is improved, and the coordinated optimization configuration result of the network-forming inverter and the static synchronous compensator can be efficiently obtained.

Description

Technical Field

[0001] The present invention relates to electric power grid technology, and in particular to a coordinated optimization configuration method, device, equipment and storage medium for improving the transient voltage safety of a regional power grid. Background Art

[0002] A large number of photovoltaic, wind power and other new energy sites in the power system mostly use grid-following control inverters, which cannot provide voltage support control capabilities similar to traditional synchronous generators. In addition, the voltage fluctuates greatly when the impact load starts, affecting the safe and reliable power supply to users.

[0003] In order to improve the safety of transient voltage in the power grid, optimizing the configuration of dynamic reactive power support in the power grid is a key technical means. By pre-configuring reasonable dynamic reactive power compensation devices and providing voltage support at key sites, the voltage safety level of the power grid after a system failure can be improved.

[0004] The existing dynamic reactive support optimization configuration method has the following two disadvantages:

[0005] 1. The configuration of grid-connected inverters of new energy stations with dynamic reactive power support capability is not considered, and the existing dynamic reactive power support resources in the power grid are not fully utilized. If better transient voltage safety is desired, more dynamic reactive power compensation devices need to be configured, resulting in poor economic efficiency of the obtained optimization configuration scheme.

[0006] 2. Since the current carrying capacity of power electronic devices in the grid-type inverters of new energy stations is relatively low, it is necessary to set current limiting constraints for the grid-type inverters during operation. The existing method is to express the constraints as piecewise linear functions by introducing multiple 0-1 variables. However, since the differential equations describing transient voltage safety need to be differentiated into algebraic equations for multiple time periods in the optimization solution, the current limiting constraints for all time periods result in a large number of 0-1 variables that need to be introduced, making the optimization configuration model inefficient or even unsolvable. Summary of the invention

[0007] The present invention provides a coordinated optimization configuration method, device, equipment and storage medium for improving the transient voltage safety of a regional power grid, so as to improve the transient voltage safety of the power system and improve the calculation efficiency of model solving.

[0008] In a first aspect, the present invention provides a coordinated optimization configuration method for improving the transient voltage safety of a regional power grid, comprising:

[0009] Taking the sum of the installation cost of the static synchronous compensator and the reconstruction cost of the grid-type inverter as the objective function, and taking the dynamic model constraints of the static synchronous compensator, the dynamic model constraints of the grid-type inverter, the current limiting constraints of the grid-type inverter, the dynamic model constraints of the grid-following inverter, the dynamic model constraints of the synchronous generator, the dynamic model constraints of the conventional load, the dynamic model constraints of the impact load, the network operation constraints and the transient voltage safety constraints as constraints, a coordinated optimization configuration model is constructed, wherein the current limiting constraint of the grid-type inverter is a piecewise function constraint;

[0010] rewriting the coordinated optimization configuration model into a compact coordinated optimization configuration model;

[0011] Converting the differential equation constraints in the compact form of the coordinated optimization configuration model into nonlinear algebraic equations;

[0012] Rewriting the grid-type inverter current limiting constraint into a polynomial interpolation function by using a Lagrange interpolation method, and using the polynomial interpolation function to approximately express the grid-type inverter current limiting constraint;

[0013] The transformed compact form of the coordinated optimization configuration model is solved to obtain the optimal configuration solution.

[0014] In a second aspect, the present invention further provides a coordinated optimization configuration device for improving the transient voltage safety of a regional power grid, comprising:

[0015] A model building module is used to build a coordinated optimization configuration model with the sum of the installation cost of the static synchronous compensator and the reconstruction cost of the grid-type inverter as the objective function, and with the dynamic model constraints of the static synchronous compensator, the dynamic model constraints of the grid-type inverter, the current limiting constraints of the grid-type inverter, the dynamic model constraints of the grid-following inverter, the dynamic model constraints of the synchronous generator, the dynamic model constraints of the conventional load, the dynamic model constraints of the impact load, the network operation constraints and the transient voltage safety constraints as constraints, wherein the current limiting constraints of the grid-type inverter are piecewise function constraints;

[0016] A model rewriting module, used for rewriting the coordinated optimization configuration model into a compact coordinated optimization configuration model;

[0017] A constraint conversion module, used for converting the differential equation constraints in the compact form coordinated optimization configuration model into nonlinear algebraic equations;

[0018] A function rewriting module, used to rewrite the current limiting constraint of the grid-type inverter into a polynomial interpolation function by using a Lagrange interpolation method, and to approximate the current limiting constraint of the grid-type inverter by using the polynomial interpolation function;

[0019] The model solving module is used to solve the transformed compact coordinated optimization configuration model to obtain an optimized configuration solution.

[0020] In a third aspect, the present invention further provides an electronic device, comprising:

[0021] one or more processors;

[0022] A storage device for storing one or more programs;

[0023] When the one or more programs are executed by the one or more processors, the one or more processors implement the coordinated optimization configuration method for improving the transient voltage safety of the regional power grid as provided in the first aspect of the present invention.

[0024] In a fourth aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the coordinated optimization configuration method for improving the transient voltage safety of a regional power grid as provided in the first aspect of the present invention.

[0025] The coordinated optimization configuration method for improving the transient voltage safety of a regional power grid provided by the present invention takes the sum of the installation cost of a static synchronous compensator and the reconstruction cost of a grid-type inverter as the objective function, and takes the dynamic model constraints of the static synchronous compensator, the dynamic model constraints of the grid-type inverter, the current limiting constraints of the grid-type inverter, the dynamic model constraints of the grid-type inverter, the dynamic model constraints of the synchronous generator, the dynamic model constraints of the conventional load, the dynamic model constraints of the impact load, the network operation constraints and the transient voltage safety constraints as constraint conditions to construct a coordinated optimization configuration model, wherein the current limiting constraints of the grid-type inverter are piecewise function constraints, the coordinated optimization configuration model is rewritten into a compact coordinated optimization configuration model, the differential equation constraints in the compact coordinated optimization configuration model are converted into nonlinear algebraic equations, the Lagrange interpolation method is used to rewrite the current limiting constraints of the grid-type inverter into polynomial interpolation functions, and the polynomial interpolation functions are used to approximate the current limiting constraints of the grid-type inverter, the converted compact coordinated optimization configuration model is solved, and an optimized configuration scheme is obtained. While configuring the reactive power compensation device, consideration is also given to converting the grid-type inverters of new energy stations into grid-type inverters, thereby improving the transient voltage safety of the power system. There is no need to use piecewise functions to process the current limiting constraints, thereby avoiding the introduction of a large number of 0-1 variables in the model and improving the computational efficiency of the model solution.

[0026] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 A flow chart of a coordinated optimization configuration method for improving the transient voltage safety of a regional power grid provided by the present invention;

[0029] Figure 2 This is a comparison chart of the polynomial interpolation function and the original piecewise function;

[0030] Figure 3 This is a schematic diagram of the structure of the modified IEEE39 node system with new energy stations and impact load access;

[0031] Figure 4 Comparison of load voltage curves when a three-phase short circuit occurs at the midpoint of line 14-15 before and after the optimization configuration;

[0032] Figure 5 Comparison of load voltage curves when three-phase short circuit occurs at the midpoint of line 3-4 before and after optimization configuration;

[0033] Figure 6 Comparison of load voltage curves when three-phase short circuit occurs at the midpoint of line 5-8 before and after the optimization configuration;

[0034] Figure 7 Comparison of load voltage curves before and after impact load startup for optimized configuration;

[0035] Figure 8 A schematic diagram of the structure of a coordinated optimization configuration device for improving the transient voltage safety of a regional power grid provided by the present invention;

[0036] Fig. 9 The present invention provides a schematic structural diagram of an electronic device.

[0037] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings 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 should fall within the scope of protection of the present invention.

[0039] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0040] Figure 1 The present invention provides a flowchart of a coordinated optimization configuration method for improving the transient voltage safety of a regional power grid. This embodiment is applicable to the case where a regional power grid is modified to improve the transient voltage safety of the regional power grid. The method can be performed by a coordinated optimization configuration device for improving the transient voltage safety of a regional power grid provided by the present invention. The device can be implemented by software and / or hardware, and is usually configured in an electronic device, such as Figure 1 As shown, the coordinated optimization configuration method for improving the transient voltage safety of the regional power grid includes the following steps:

[0041] S101. Taking the sum of the installation cost of the static synchronous compensator and the reconstruction cost of the grid-connected inverter as the objective function, and taking the dynamic model constraints of the static synchronous compensator, the dynamic model constraints of the grid-connected inverter, the current limiting constraints of the grid-connected inverter, the dynamic model constraints of the grid-following inverter, the dynamic model constraints of the synchronous generator, the dynamic model constraints of the conventional load, the dynamic model constraints of the impact load, the network operation constraints and the transient voltage safety constraints as constraints, a coordinated optimization configuration model is constructed, wherein the current limiting constraint of the grid-connected inverter is a piecewise function constraint.

[0042] Static synchronous compensator (STATCOM) is a parallel type reactive power compensation FACTS device, which can generate or absorb reactive power, and its output can be changed to control specific parameters in the power system. Generally, it is a solid-state switching converter. When its input is connected to a power supply or energy storage device, its output can independently generate or absorb controllable active and reactive power; it can improve the function of the power system in the following aspects: dynamic voltage control, power oscillation damping, transient stability, voltage flicker control, etc. Compared with traditional reactive power compensation devices, STATCOM has the advantages of continuous regulation, small harmonics, low loss, wide operating range, high reliability, and fast regulation speed. Since its advent, it has received widespread attention and rapid development.

[0043] A grid-type inverter is a device that converts DC power into AC power. Its core technology is to achieve the conversion between DC and AC through the switching action of power electronic devices. A grid-type inverter can simulate the power generation mode of a synchronous generator to form a stable voltage and frequency, thereby acting as a voltage source in a local microgrid. A grid-type inverter is different from a grid-following inverter. The latter is a current source inverter that is connected to the grid through a phase-locked loop and feeds energy into the grid; while a grid-type inverter can be used as a voltage source for a local microgrid, forming a stable voltage and frequency by simulating the power generation mode of a synchronous generator. Typical control methods include droop control and virtual synchronous generator control.

[0044] In the embodiment of the present invention, a static synchronous compensator is installed in the power grid, and some grid-following inverters are transformed into grid-building inverters.

[0045] In the embodiment of the present invention, the sum of the installation cost of the static synchronous compensator and the reconstruction cost of the grid-type inverter is taken as the objective function, and the dynamic model constraints of the static synchronous compensator, the dynamic model constraints of the grid-type inverter, the current limiting constraints of the grid-type inverter, the dynamic model constraints of the grid-type inverter, the dynamic model constraints of the synchronous generator, the dynamic model constraints of the conventional load, the dynamic model constraints of the impact load, the network operation constraints and the transient voltage safety constraints are taken as the constraints to construct a coordinated optimization configuration model, wherein the current limiting constraint of the grid-type inverter is a piecewise function constraint. The decision variables of the model are the number of reconstruction nodes of the grid-type inverter and the number and capacity of the configuration nodes of the static synchronous compensator.

[0046] Exemplarily, the objective function is:

[0047]

[0048] Among them, μ si and μ Ei A variable that is either 0 or 1, μ si and μ EiThe value of 1 or 0 indicates whether a static synchronous compensator is connected to node i and whether the new energy station at node i is converted into a grid-connected inverter; C s0 and C s1 is the fixed installation cost of the static synchronous compensator and the cost proportional to the capacity; C E0 and C E1 is the fixed reconstruction cost of the grid-connected inverter and the cost proportional to the active power of the new energy station at the node; S sti and P Gi It is the installed capacity of the static synchronous compensator and the active power generated by the new energy station.

[0049] The static synchronous compensator can provide dynamic reactive power support to the power grid when the bus voltage drops, thereby improving the recovery speed of the system bus voltage in the event of a short-circuit fault and reducing the fluctuation amplitude of the bus voltage when the impact load starts, improving the transient voltage safety of the system, and thus improving the power supply reliability of users.

[0050] The dynamic model constraints of the static synchronous compensator are:

[0051]

[0052] Among them, I si is the injection current amplitude of the static synchronous compensator control node i; U srefi K is the voltage reference value of the static synchronous compensator control node i; p , X T and T s is the gain factor, equivalent reactance and time constant of the static synchronous compensator controller; S base k is the configuration capacity base value of the static synchronous compensator; sti is an integer variable, indicating that the configuration capacity of the static synchronous compensator is a multiple of the base value; V i is the node voltage amplitude of the static synchronous compensator control node i; V xi and V yi is the real and imaginary part of the voltage at node i; I sxi and I syi The real and imaginary parts of the current injected into node i for the static synchronous compensator control.

[0053] The grid-forming inverter is similar to the synchronous machine. It generally shows the characteristics of a voltage source. It has the ability to independently build voltage, provide stable AC voltage, and improve the transient stability of the power grid. The dynamic model constraints of the grid-forming inverter controlled by the virtual synchronous machine are:

[0054]

[0055] Among them, θ Gi and ω Giis the power angle and angular velocity of the grid-connected inverter at node i; ω N and ω s are the synchronous angular velocity and the reference angular velocity; E i is the internal potential of the grid-connected inverter at node i; D n and D q is the inverse of the damping and amplifier gain factor; G m and B m is the equivalent conductance and susceptance; J is the inertia time constant of the control link. Ti , Q Ti and E i * are the active power reference value, reactive power reference value and potential reference value of the grid-connected inverter at node i respectively. vxi_out and I vyi_out are the real and imaginary parts of the output current of the new energy station using the grid-type control node i.

[0056] The grid-type inverter has the characteristics of a voltage source. When a short-circuit fault occurs in the grid or an impact load starts, in order to keep its internal potential relatively constant, the current it outputs to the grid depends on the characteristics of the external circuit. The synchronous generator can provide a short-circuit current of 5 to 7 (per unit) in the event of a fault; however, due to the current-carrying capacity of the power electronic devices themselves, the short-circuit current that the grid-type inverter can withstand is only 1.2-2 (per unit). Therefore, during the fault period, in order to prevent the inverter's own overcurrent protection from operating, the grid-type inverter current limiting constraint needs to be introduced:

[0057]

[0058] Among them, I vxi ,I vyi and I vi I is the real part, imaginary part and amplitude of the grid current injected into the new energy station using the grid-type control node i; vi_out is the output current amplitude of the new energy station using the grid-type control node i, I vi_max For I vi The maximum value of .

[0059] Most of the inverters in the current power grid use grid-following control. Grid-following control obtains the voltage phasor information of the grid connection point through a phase-locked loop to maintain synchronous operation with the grid. The dynamic model constraints of the grid-following inverter include the phase-locked loop control equation and the outer loop power control equation, as shown in equations (5) and (6) respectively:

[0060]

[0061] Among them, θ PLLi and ω PLLiIt is the output power angle and output angular velocity of the phase-locked loop in node i of the new energy station that adopts grid-following control; I edi and I eqi are the d-axis and q-axis components of the phase-locked loop output current; K p and K i is the parameter of the PI control loop in the phase-locked loop; R g and L g is the equivalent resistance and inductance of the grid-side transformer; k 1i , k 2i , k 3i , k 4i and M i is the intermediate parameter of node i and network type control. Pi and x Qi It is the state quantity introduced to control the output active power and reactive power of renewable energy; P emi and Q emi is the active and reactive power output by the converter of the new energy station under the control of the phase-locked loop; P erefi and Q erefi YesP emi and Q emi Reference setting value; P ei and Q ei is the active and reactive power injected by the new energy station into the grid node i under the control of the phase-locked loop; K pgd and K igd is the parameter in the active power PI control loop; K pgq and K igq is the parameter in the reactive power PI control loop; I gxi and I gyi The real and imaginary parts of the grid current injected into the new energy station using the grid-following control node i.

[0062] The synchronous generator in the system adopts a third-order dynamic model and a first-order excitation dynamic model. The dynamic model constraints of the synchronous generator are:

[0063]

[0064] Among them, δ i and ω i is the power angle and angular velocity of the synchronous generator at node i; E qi ' and E fi is the transient potential and excitation potential of the synchronous generator at node i; qi and i di are the quadrature-axis current and direct-axis current of the synchronous generator at node i; D i and P Ti is the damping and mechanical power of the synchronous generator at node i; X di and X di' is the d-axis reactance and transient d-axis reactance of the synchronous generator at node i; T Ji , T d0i '、T E and K A is the inertia time constant, transient open circuit time constant, excitation winding time constant and amplification factor of the synchronous generator at node i; di and i qi is the d-axis and q-axis current amplitude output by the synchronous generator at node i; V di and V qi I is the d-axis and q-axis voltage amplitude of the synchronous generator at node i; xi and I yi is the real and imaginary parts of the grid current injected into node i; G xi , B xi , B yi , G yi is the admittance of generator i and its salient pole effect into the network, which are its parameters R ai , X di , X di ′、X qi and power angle δ i function.

[0065] The dynamic modeling of conventional loads adopts the commonly used three-order electromechanical transient induction motor parallel constant impedance dynamic model. The dynamic model constraints of conventional loads are:

[0066]

[0067] Among them, e xi ' and e yi ' is the real and imaginary parts of the transient potential of the induction motor at node i, s i is the slip rate of the induction motor at node i, T' d0l is the decay time constant of the transient potential, r 1i 、x i and x i ' is the stator resistance, synchronous reactance and transient reactance of the induction motor at node i, T JL is the rotor inertia time constant, K L is the load rate, a is the percentage of the mechanical load that is not related to the speed, n p is the load index; K Hi It is the capacity conversion ratio of the induction motor at node i, that is, the ratio of the system capacity base value to the capacity base value of the induction motor at node i.

[0068] Large motor loads are typical impact loads. At present, most of the impact loads in the power system are steel mills and high-speed rail traction loads, which are typical motor load impact loads. Direct starting is often used. This method requires simple equipment, short start-up time, and low cost, but it will cause a large impact on the power grid. The instantaneous impact current of the motor starting can be as high as several times to more than ten times the rated value, causing sharp fluctuations in the voltage and frequency of the power system. During normal operation, the impact load can be regarded as the same as the conventional motor load, so the dynamic model of the three-order electromechanical transient induction motor parallel constant impedance in equation (8) can be used. However, the impact current of the impact load at the moment of starting can be as high as several times to more than ten times the rated value. The traditional induction motor parallel constant impedance dynamic model cannot accurately describe the impact process of the motor starting moment, and it is necessary to accurately model the impact process of the impact load starting moment. Therefore, based on the physical mechanism analysis of the dynamic model of the three-order electromechanical transient induction motor, the time-varying values ​​of the dynamic parameters are identified by the least squares method using historical measured data. The dynamic model constraints of the impact load are:

[0069]

[0070] Among them, K Hi (t), r 1i (t) and x i ′(t) is a time-varying dynamic parameter identified by the historical measured data-driven method of the impact load startup process of node i.

[0071] The specific calculation steps are as follows: Based on the node voltage and injection current V during the impact load startup process in the historical measured data sample xi , V yi , I xi , I yi Based on the least squares method, the optimization model (10) is solved to identify the time-varying dynamic parameter K of the impact load startup process. Hi (t), r 1i (t) and x i ′(t), thus obtaining a dynamic model that accurately describes the impact load startup process. After the impact load startup, when the current returns to a relatively stable state, the original three-order electromechanical transient induction motor parallel constant impedance dynamic model (8) is used to describe its normal operation process.

[0072]

[0073] In the formula, z xi and z yi It represents the deviation between the measured current and the current calculated by the impact load model. The superscript b represents the variable value corresponding to the bth sample.

[0074] The network operation constraints include the power flow equation constraints in the steady state and the algebraic equation group constraints describing the voltage and current of each node in the transient process. The power flow constraints in the steady state are:

[0075]

[0076] Among them, P Gi and Q Gi P is the active and reactive power output of the synchronous generator in steady state; ei and Q ei P is the active and reactive power output of the renewable energy station in steady state; Li and Q Li I is the active and reactive loads in steady state for normal load and impact load; si0 is the current amplitude injected into the node by STATCOM; V i0 ,V xi0 ,V yi0 is the voltage amplitude of node i and its corresponding rectangular coordinate component in steady state; G ij and B ij are the mutual conductance and mutual susceptance between nodes i and j.

[0077] The algebraic equations for the voltage and current at each node used in the transient process are constrained as follows:

[0078] I+μ s I s +μ E I v +(1-μ E )I g =(Y0+Y′)V (12)

[0079] Where: V = [V x1 ,V y1 ,…,V xi ,V yi ,…,V xn ,V yn ] T is the node voltage vector; Y0 is the network node admittance matrix; Y'=diag(Y1′,…,Y i ′,…,Y n ′) is a matrix composed of the admittance of the generator and the load connected to the network; I = [I x1 ,I y1 ,…,I xi ,I yi ,…I xn ,I yn ] T is the vector formed by the injected current of the synchronous generator and the load node; I s =[I sx1 ,Isy1 ,…,I sxi ,I syi ,…I sxn ,I syn ] T is the vector formed by the current injected by the STATCOM installation node to be selected; I v =[I vx1 ,I vy1 ,…,I vxi ,I vyi ,…I vxn ,I vyn ] T is a vector composed of the current injected by the nodes of the new energy station to be converted into a grid-connected inverter; I g =[I gx1 ,I gy1 ,…,I gxi ,I gyi ,…I gxn ,I gyn ] T is a vector formed by the current injected by the new energy station node of the grid-following inverter; μ s =diag(μ s1 ,…,μ si ,…,μ sn ) is a vector of binary variables, which takes 1 when connected to STATCOM and 0 otherwise; μ E =diag(μ E1 ,…,μ Ei ,…,μ En ) is a vector composed of binary variables. It takes 1 when the new energy station is converted from a grid-following inverter to a grid-building inverter, otherwise it takes 0.

[0080] If node i is a synchronous generator node, then

[0081]

[0082] If node i is a normal load or impact load node, then

[0083]

[0084] In the formula, G i and B i are the conductance and susceptance of the static part of load node i.

[0085] If node i is a node without synchronous generator, normal load or impact load, then

[0086]

[0087] When a fault occurs in the power system, according to my country's current transient voltage safety standards, the bus voltage is restored to above 0.75 (unit value) 1 second after the fault is cleared, as follows:

[0088] V i (t c +t lim )≥V lim (16)

[0089] Where: V i is the voltage amplitude of bus i; t c is the fault clearing time, t lim =1s, V lim =0.75 (per unit value).

[0090] Transient power angle stability criterion: Taking the generator power angle of the balance node as the reference benchmark, the relative rotation angle of the remaining generators does not exceed 150 degrees as the criterion for the stability of the generator in the power system, as follows:

[0091] |δ i (t)-δ ref (t)|≤δ max (17)

[0092] Where: ref (t) is the power angle of the generator at the balance node at time t, δ i (t) is the power angle of the synchronous generator at node i at time t, δ max is 150 degrees.

[0093] During the impact load startup process, the transient voltage safety of the power system should not exceed the voltage safety operating range according to the operating standard during the impact load startup process, as follows:

[0094] V imin ≤V i (t)≤V imax (18)

[0095] Where: The lower and upper limits of the voltage safe operating range are V imin = 0.9 (per unit value) and V imax =1.1(per unit value).

[0096] S102: rewrite the coordinated optimization configuration model into a compact coordinated optimization configuration model.

[0097] In summary, the coordinated optimization configuration model of the grid-forming inverter and the static synchronous compensator for improving the transient voltage safety of the regional power grid is formed by equations (1)-(18), which can be expressed in a compact form as shown in equation (19), where the differential equation group includes the dynamic equations of the synchronous generator and the excitation system, i.e., equations 1 to 4 in equation (7), the dynamic equations of the grid-forming inverter and the grid-following inverter of the new energy station, i.e., equations 1 to 2 in equations (3), (5) and (6), and the dynamic equations of the conventional load and the impact load, i.e., equations 1 to 3 in equations (8) and (9). The dynamic equation of the static synchronous compensator is the first equation in equation (2), and the rest of the algebraic equation group includes the first, second, and fourth equations in equation (2), the third to fifth equations in equation (3), equation (4), the third to seventh equations in equation (5), the third to seventh equations in equation (6), the fifth to fourteenth equations in equation (7), the fourth to fifth equations in equation (8), the fourth to fifth equations in equation (9), equations (11) to (15), and the inequality constraint part includes the third equation in equation (2) and equations (16) to (18).

[0098] The compact form of the coordinated optimization configuration model is expressed as:

[0099]

[0100] Among them, x and y are optimization variables.

[0101] S103. Convert the differential equation constraints in the compact coordinated optimization configuration model into nonlinear algebraic equations.

[0102] For the established model (19), since it contains the constraints of a differential equation group, the current commercial solver cannot solve it directly. It is necessary to use the implicit trapezoidal integration method for differentiation to transform the differential equation group into a series of nonlinear algebraic equations. The transformed model is shown in formula (20):

[0103]

[0104] Where h is the step size of a single period set by the implicit trapezoidal method.

[0105] S104, rewriting the current limiting constraint of the grid-type inverter into a polynomial interpolation function using the Lagrange interpolation method, and using the polynomial interpolation function to approximate the current limiting constraint of the grid-type inverter.

[0106] The proposed coordinated planning model needs to consider multiple severe three-phase short-circuit faults and impact load startup transient processes of multiple operating conditions at the same time. If the step length of a single period is h = 0.02s, the 10s transient process of each operating condition needs to be considered for a total of 2000 periods. At this time, the scale of the optimization model is huge and difficult to solve, so it is necessary to make certain simplifications.

[0107] For three-phase short-circuit faults, the following two characteristics are observed: 1) the transient stability can be determined by the first swing of the load bus voltage curve; 2) in the case of transient stability, the lowest point value of each swing of the load bus voltage curve gradually increases. Therefore, it is only necessary to consider that the voltage lowest point of the first swing of the load bus voltage curve meets the transient voltage safety constraint, and the entire bus load voltage curve meets the transient voltage safety constraint. And the lowest point of the first swing of the load voltage curve will occur within 2.5s after the fault is cleared. Considering a certain margin, only the transient process of the three-phase short-circuit fault for a total of 3s needs to be considered. For the start-up process of the impact load, when the impact load is just started, it will bring a sharp voltage drop, and after the impact load is started, the load bus voltage will still have a certain fluctuation, and the fluctuation amplitude is getting smaller and smaller. At the same time, the first swing of the load bus voltage curve will occur within 3s after the impact load is started. Similarly, only the transient process of the impact load for a total of 3s needs to be considered. In this way, the calculation scale of the transient process of short-circuit fault and impact load startup in the coordinated optimization planning model is reduced to 30% of the original.

[0108] For the piecewise function constraint in formula (4), a common method is to introduce 0-1 variables to express it as a piecewise linear function. Taking the first piecewise function in formula (4) as an example, it can be transformed into the form shown in formula (21).

[0109]

[0110] Where: α i M is a large positive number introduced as a 0-1 variable, and is set to 10,000 in the present invention.

[0111] The above method is concise and accurate in processing piecewise functions, but it will introduce a large number of 0-1 variables, which will greatly increase the scale of the optimization model and make it difficult to solve. In order to avoid introducing a large number of 0-1 variables and thus increase the difficulty of solving the optimization model, a piecewise function approximation method based on Lagrange interpolation is proposed to describe the current limiting constraint of the grid-type inverter. By setting five anchor points (0,0), (I N ,I N )、(I max ,I max )、(1.25I max ,I max ) and (1.5I max ,I max ), and then the polynomial interpolation function is obtained through Lagrange interpolation based on these five anchor points. The polynomial interpolation function is used to approximately describe the current limiting constraint of the grid-connected inverter. The comparison between the polynomial interpolation function approximately described by the piecewise function in equation (4) and the original piecewise function is as follows: Figure 2 As shown in the figure, the broken line represents the original piecewise function, and the smooth curve represents the polynomial interpolation function. The expression of the polynomial interpolation function is shown in formula (22).

[0112]

[0113] Among them, λ vi1 , vi2 , vi3 , vi4 are the four terms of Lagrange interpolation; I viN For I vi The five anchor points are (0,0), (I N ,I N )、(I max ,I max )、(1.25I max ,I max ) and (1.5I max ,I max ).

[0114] S105. Solve the coordinated optimization configuration model in the transformed compact form to obtain an optimized configuration solution.

[0115] Through the above process, the model containing differential equation constraints and piecewise linear function constraints proposed by the present invention can be transformed into mixed integer nonlinear programming models (1)-(3), (5)-(18), (22). This model can be directly solved by calling the SBB solver using the commercial optimization software GAMS (The General Algebraic Modeling System) to obtain an optimal configuration solution.

[0116] The coordinated optimization configuration method for improving the transient voltage safety of a regional power grid provided by the present invention takes the sum of the installation cost of a static synchronous compensator and the reconstruction cost of a grid-type inverter as the objective function, and takes the dynamic model constraints of the static synchronous compensator, the dynamic model constraints of the grid-type inverter, the current limiting constraints of the grid-type inverter, the dynamic model constraints of the grid-type inverter, the dynamic model constraints of the synchronous generator, the dynamic model constraints of the conventional load, the dynamic model constraints of the impact load, the network operation constraints and the transient voltage safety constraints as constraint conditions to construct a coordinated optimization configuration model, wherein the current limiting constraints of the grid-type inverter are piecewise function constraints, the coordinated optimization configuration model is rewritten into a compact coordinated optimization configuration model, the differential equation constraints in the compact coordinated optimization configuration model are converted into nonlinear algebraic equations, the Lagrange interpolation method is used to rewrite the current limiting constraints of the grid-type inverter into polynomial interpolation functions, and the polynomial interpolation functions are used to approximate the current limiting constraints of the grid-type inverter, the converted compact coordinated optimization configuration model is solved, and an optimized configuration scheme is obtained. While configuring the reactive power compensation device, consideration is also given to converting the grid-type inverters of new energy stations into grid-type inverters, thereby improving the transient voltage safety of the power system. There is no need to use piecewise functions to process the current limiting constraints, thereby avoiding the introduction of a large number of 0-1 variables in the model and improving the computational efficiency of the model solution.

[0117] Example analysis:

[0118] The modified IEEE39 node system with new energy stations and impact load access is used as an example for analysis. Wind farms are connected at nodes 13 and 34, photovoltaic power stations are connected at nodes 17 and 35, and impact loads are connected at nodes 8 and 20. Considering the transient processes of four operating conditions in which three-phase short-circuit faults occur at the midpoints of the three lines in the system and impact loads are started, the coordinated optimization configuration results of the grid-connected inverter and static synchronous compensator are obtained by solving the proposed coordinated optimization configuration model so that the transient processes of the four operating conditions meet the transient safety requirements, verifying the accuracy of the proposed coordinated optimization configuration model and solution method. The detailed topology of the system is shown in Figure 2. Figure 3 As shown. It is set that three phase short circuit faults occur at the midpoints of lines 14-15, 3-4, and 5-8, and the impact load at nodes 8 and 20 is started. The transient processes of the four operating conditions mentioned above all occur at t = 0.2s, the differential step length h = 0.02s, and the total differential duration of the transient process is 3s. The maximum current amplitude I injected into the grid by the grid-forming inverter vimax =1.8I N ; The nodes to be selected for reconstruction of the grid-type inverter are 13, 17, 34, and 35, and the reconstruction cost coefficient of the grid-type inverter is C E0 =30 million, C E1= 250,000 / MVA; the nodes to be selected for the installation of the static synchronous compensator are 4, 8, 14, and 20, which are the end of the line where the three-phase short-circuit fault occurs and the node where the impact load is connected. The installation cost coefficient of the static synchronous compensator is C s0 =20 million, C s1 = 200,000 / MVA. The computer hardware environment used for the example test is 32G memory and 12th Gen Intel(R)Core(TM)i7-12700F CPU@2.10GHz CPU, and the program is programmed in the GAMSwin6424.5.6 version software environment.

[0119] 1. Analysis of coordination and optimization configuration results

[0120] The results of solving the coordinated optimization configuration model of the proposed new energy station grid-connected inverter and static synchronous compensator are shown in Table 1.

[0121] Table 1 Coordinated optimization configuration scheme of grid-connected inverter and STATCOM

[0122]

[0123] The voltage variation curves of each load busbar in the transient process of the four operating conditions are as follows: Figures 4 to 7 As shown in Table 1, the coordinated optimization configuration result is to configure static synchronous compensators at nodes 14 and 20, and transform the photovoltaic power station inverter at node 17 from grid-following control to grid-forming control. Figures 3 to 6 It can be seen that before the optimal configuration of the grid-forming inverter and static synchronous compensator, the system suffered severe transient voltage instability under the three three-phase short-circuit faults. When the impact load started, the load bus voltage would exceed the safe operating range of the grid voltage. After the grid-forming inverter and static synchronous compensator were configured at the corresponding nodes, the three three-phase short-circuit faults were able to maintain transient safety constraints, maintain transient voltage stability, and recover quickly. After the fault was removed for 1 second, the voltage of all load nodes could be restored to above 0.75pu; Figure 7 As shown in the figure, for the start-up process of the impact load, the voltage sag amplitude is reduced when the impact load is just started, and it can stay within the safe operating range of the grid voltage. After the impact load is started, the voltage fluctuation amplitude of the load is also reduced, and it can quickly recover to the normal operating voltage of the grid. It is verified that converting the grid-following inverter into a grid-building inverter and configuring a static synchronous compensator can effectively improve the transient voltage safety of the system.

[0124] 2. Comparative analysis of various configuration scheme results

[0125] The optimized configuration schemes obtained by configuring the static synchronous compensator and the grid-connected inverter separately in the system are compared with the optimized configuration scheme obtained by the proposed coordinated optimization configuration method, and the results are shown in Table 1-3. It can be seen that the optimized configuration scheme obtained by configuring the static synchronous compensator separately can support the power system to meet the transient voltage safety constraints after a short-circuit fault and during the start-up of the impact load; the optimized configuration scheme obtained by configuring the grid-connected inverter separately has a cost close to that of the scheme of configuring the static synchronous compensator separately, and the grid-connected inverter is also very capable of improving the transient voltage safety of the power system, but in general, the cost of configuring a single device is relatively high; the coordinated optimization configuration scheme of the grid-connected inverter and the static synchronous compensator can not only support the power system to meet the transient voltage safety requirements after a short-circuit fault and during the start-up of the impact load, but also significantly reduce the cost. Therefore, the coordinated optimization configuration of the grid-connected inverter and the static synchronous compensator can better play the performance of the two devices in dynamically supporting voltage, and can further improve the transient voltage safety of the power system.

[0126] Table 2 Optimal configuration scheme obtained by configuring STATCOM alone

[0127]

[0128]

[0129] Table 3 Optimal configuration scheme obtained by configuring grid-connected inverters alone

[0130]

[0131] Figure 8 A schematic diagram of the structure of a coordinated optimization configuration device for improving the transient voltage safety of a regional power grid provided by the present invention is shown in FIG. Figure 8 As shown, the coordinated optimization configuration device for improving the transient voltage safety of the regional power grid includes:

[0132] The model building module 201 is used to build a coordinated optimization configuration model with the sum of the installation cost of the static synchronous compensator and the reconstruction cost of the grid-type inverter as the objective function, and with the dynamic model constraints of the static synchronous compensator, the dynamic model constraints of the grid-type inverter, the current limiting constraints of the grid-type inverter, the dynamic model constraints of the grid-type inverter, the dynamic model constraints of the synchronous generator, the dynamic model constraints of the conventional load, the dynamic model constraints of the impact load, the network operation constraints and the transient voltage safety constraints as constraints, wherein the current limiting constraints of the grid-type inverter are piecewise function constraints;

[0133] A model rewriting module 202, used to rewrite the coordinated optimization configuration model into a compact coordinated optimization configuration model;

[0134] A constraint conversion module 203, used to convert the differential equation constraints in the compact coordinated optimization configuration model into nonlinear algebraic equations;

[0135] A function rewriting module 204 is used to rewrite the grid-type inverter current limiting constraint into a polynomial interpolation function using a Lagrange interpolation method, and use the polynomial interpolation function to approximately express the grid-type inverter current limiting constraint;

[0136] The model solving module 205 is used to solve the transformed compact coordinated optimization configuration model to obtain an optimization configuration solution.

[0137] In some embodiments of the present invention, the objective function is:

[0138]

[0139] Among them, μ si and μ Ei A variable that is either 0 or 1, μ si and μ Ei The value of 1 or 0 indicates whether a static synchronous compensator is connected to node i and whether the new energy station at node i is converted into a grid-connected inverter; C s0 and C s1 is the fixed installation cost of the static synchronous compensator and the cost proportional to the capacity; C E0 and C E1 is the fixed reconstruction cost of the grid-connected inverter and the cost proportional to the active power of the new energy station at the node; S sti and P Gi It is the installed capacity of the static synchronous compensator and the active power generated by the new energy station.

[0140] In some embodiments of the present invention, the dynamic model constraints of the static synchronous compensator are:

[0141]

[0142] Among them, I si is the injection current amplitude of the static synchronous compensator control node i; U srefi K is the voltage reference value of the static synchronous compensator control node i; p , X T and T s is the gain factor, equivalent reactance and time constant of the static synchronous compensator controller; S base k is the configuration capacity base value of the static synchronous compensator; sti is an integer variable, indicating that the configuration capacity of the static synchronous compensator is a multiple of the base value; V i is the node voltage amplitude of the static synchronous compensator control node i; V xi and Vyi is the real and imaginary part of the voltage at node i; I sxi and I syi The real and imaginary parts of the current injected into the static synchronous compensator control node i;

[0143] The dynamic model constraints of the grid-connected inverter are:

[0144]

[0145] Among them, θ Gi and ω Gi is the power angle and angular velocity of the grid-connected inverter at node i; ω N and ω s are the synchronous angular velocity and the reference angular velocity; E i is the internal potential of the grid-connected inverter at node i; D n and D q is the inverse of the damping and amplifier gain factor; G m and B m is the equivalent conductance and susceptance; J is the inertia time constant of the control link. Ti , Q Ti and E i * are the active power reference value, reactive power reference value and potential reference value of the grid-connected inverter at node i respectively. vxi_out and I vyi_out are the real and imaginary parts of the output current of the new energy station using the grid-type control node i;

[0146] The current limiting constraint of the grid-connected inverter is:

[0147]

[0148] Among them, I vxi ,I vyi and I vi I is the real part, imaginary part and amplitude of the grid current injected into the new energy station using the grid-type control node i; vi_out is the output current amplitude of the new energy station using the grid-type control node i, I vi_max For I vi The maximum value of

[0149] The dynamic model constraints of the grid-following inverter are:

[0150]

[0151] Among them, θ PLLi and ω PLLi It is the output power angle and output angular velocity of the phase-locked loop in node i of the new energy station that adopts grid-following control; I edi and Ieqi are the d-axis and q-axis components of the phase-locked loop output current; K p and K i is the parameter of the PI control loop in the phase-locked loop; R g and L g is the equivalent resistance and inductance of the grid-side transformer; k 1i , k 2i , k 3i , k 4i and M i is the intermediate parameter of node i and network type control. Pi and x Qi It is the state quantity introduced to control the output active power and reactive power of renewable energy; P emi and Q emi is the active and reactive power output by the converter of the new energy station under the control of the phase-locked loop; P erefi and Q erefi YesP emi and Q emi Reference setting value; P ei and Q ei is the active and reactive power injected by the new energy station into the grid node i under the control of the phase-locked loop; K pgd and K igd is the parameter in the active power PI control loop; K pgq and K igq is the parameter in the reactive power PI control loop; I gxi and I gyi The real and imaginary parts of the grid current injected into the new energy station using the grid-following control node i;

[0152] The dynamic model constraints of the synchronous generator are:

[0153]

[0154] Among them, δ i and ω i is the power angle and angular velocity of the synchronous generator at node i; E qi ' and E fi is the transient potential and excitation potential of the synchronous generator at node i; qi and i di are the quadrature-axis current and direct-axis current of the synchronous generator at node i; D i and P Ti is the damping and mechanical power of the synchronous generator at node i; X di and X di ' is the d-axis reactance and transient d-axis reactance of the synchronous generator at node i; T Ji , T d0i '、T E and K Ais the inertia time constant, transient open circuit time constant, excitation winding time constant and amplification factor of the synchronous generator at node i; di and i qi is the d-axis and q-axis current amplitude output by the synchronous generator at node i; V di and V qi I is the d-axis and q-axis voltage amplitude of the synchronous generator at node i; xi and I yi is the real and imaginary parts of the grid current injected into node i; G xi , B xi , B yi , G yi is the admittance of generator i and its salient pole effect into the network, which are its parameters R ai , X di , X di ′、X qi and power angle δ i Function of

[0155] The dynamic model constraints for conventional loads are:

[0156]

[0157] Among them, e xi ' and e yi ' is the real and imaginary parts of the transient potential of the induction motor at node i, s i is the slip rate of the induction motor at node i, T' d0l is the decay time constant of the transient potential, r 1i 、x i and x i ' is the stator resistance, synchronous reactance and transient reactance of the induction motor at node i, T JL is the rotor inertia time constant, K L is the load rate, a is the percentage of the mechanical load that is not related to the speed, n p is the load index; K Hi is the capacity conversion ratio of the induction motor at node i, that is, the ratio of the system capacity base value to the capacity base value of the induction motor at node i;

[0158] The dynamic model constraints for impact loads are:

[0159]

[0160] Among them, K Hi (t), r 1i (t) and x i ′(t) is the time-varying dynamic parameter identified by the historical measured data-driven method of the impact load startup process of node i;

[0161] The network operation constraints are:

[0162]

[0163] Among them, P Gi and Q Gi P is the active and reactive power output of the synchronous generator in steady state; ei and Q ei P is the active and reactive power output of the renewable energy station in steady state; Li and Q Li I is the active and reactive loads in steady state for normal load and impact load; si0 is the current amplitude injected into the node by STATCOM; V i0 ,V xi0 ,V yi0 is the voltage amplitude of node i and its corresponding rectangular coordinate component in steady state; G ij and B ij is the mutual conductance and mutual susceptance between nodes i and j;

[0164] The transient voltage safety constraints are:

[0165] V imin ≤V i (t)≤V imax ;

[0166] Among them, V i is the voltage amplitude of bus i, Vi min The lower limit of the voltage safe operating range, Vi max The upper limit of the safe operating range of voltage.

[0167] In some embodiments of the present invention, the function rewriting module 204 includes:

[0168] An anchor point setting submodule, used for setting multiple anchor points for the current limiting constraint of the grid-connected inverter;

[0169] The interpolation calculation submodule is used to calculate the polynomial interpolation function passing through the plurality of anchor points by using the Lagrange interpolation method.

[0170] In some embodiments of the present invention, the polynomial interpolation function is:

[0171]

[0172] Among them, λ vi1 , vi2 , vi3 , vi4 are the four terms of Lagrange interpolation; I viN For I viThe five anchor points are (0,0), (I N ,I N )、(I max ,I max )、(1.25I max ,I max ) and (1.5I max ,I max ).

[0173] In some embodiments of the present invention, the coordinated optimization configuration model in a compact form is:

[0174]

[0175] Among them, x and y are optimization variables.

[0176] In some embodiments of the present invention, the nonlinear algebraic equation of the differential equation constraint in the compact form of the coordinated optimization configuration model is:

[0177]

[0178] Where h is the step size of a single period set by the implicit trapezoidal method.

[0179] The above-mentioned coordinated optimization configuration device for improving the transient voltage safety of the regional power grid can execute the coordinated optimization configuration method for improving the transient voltage safety of the regional power grid provided by the aforementioned embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the coordinated optimization configuration method for improving the transient voltage safety of the regional power grid.

[0180] Fig. 9 A schematic diagram of the structure of an electronic device provided by the present invention, the electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are only examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0181] like Fig. 9As shown, the electronic device includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0182] A number of components in the electronic device are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0183] The processor 11 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The processor 11 executes the various methods and processes described above, such as a coordinated optimization configuration method for improving the transient voltage security of a regional power grid.

[0184] In some embodiments, the coordinated optimization configuration method for improving the transient voltage safety of the regional power grid can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on an electronic device via ROM 12 and / or communication unit 19. When the computer program is loaded into RAM 13 and executed by processor 11, one or more steps of the coordinated optimization configuration method for improving the transient voltage safety of the regional power grid described above can be executed. Alternatively, in other embodiments, the processor 11 can be configured to execute the coordinated optimization configuration method for improving the transient voltage safety of the regional power grid in any other appropriate manner (for example, by means of firmware).

[0185] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0186] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0187] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0188] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0189] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0190] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0191] An embodiment of the present invention also provides a computer program product, including a computer program, which, when executed by a processor, implements a coordinated optimization configuration method for improving the transient voltage safety of a regional power grid as provided in any embodiment of the present application.

[0192] In the process of implementation, the computer program product can be written in one or more programming languages ​​or a combination thereof to perform the computer program code of the present invention, including object-oriented programming languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as "C" language or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computer (for example, using an Internet service provider to connect through the Internet).

[0193] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0194] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A coordinated optimization configuration method for improving the transient voltage safety of a regional power grid, characterized in that: include: Taking the sum of the installation cost of the static synchronous compensator and the reconstruction cost of the grid-type inverter as the objective function, and taking the dynamic model constraints of the static synchronous compensator, the dynamic model constraints of the grid-type inverter, the current limiting constraints of the grid-type inverter, the dynamic model constraints of the grid-following inverter, the dynamic model constraints of the synchronous generator, the dynamic model constraints of the conventional load, the dynamic model constraints of the impact load, the network operation constraints and the transient voltage safety constraints as constraints, a coordinated optimization configuration model is constructed, wherein the current limiting constraint of the grid-type inverter is a piecewise function constraint; rewriting the coordinated optimization configuration model into a compact coordinated optimization configuration model; Converting the differential equation constraints in the compact form of the coordinated optimization configuration model into nonlinear algebraic equations; Rewriting the grid-type inverter current limiting constraint into a polynomial interpolation function by using a Lagrange interpolation method, and using the polynomial interpolation function to approximately express the grid-type inverter current limiting constraint; The transformed compact form of the coordinated optimization configuration model is solved to obtain the optimal configuration solution.

2. The coordinated optimization configuration method for improving the transient voltage safety of a regional power grid according to claim 1 is characterized in that: The objective function is: Among them, μ si and μ Ei A variable that is either 0 or 1, μ si and μ Ei The value of 1 or 0 indicates whether a static synchronous compensator is connected to node i and whether the new energy station at node i is converted into a grid-connected inverter; C s0 and C s1 is the fixed installation cost of the static synchronous compensator and the cost proportional to the capacity; C E0 and C E1 is the fixed reconstruction cost of the grid-connected inverter and the cost proportional to the active power of the new energy station at the node; S sti and P Gi It is the installed capacity of the static synchronous compensator and the active power generated by the new energy station.

3. The coordinated optimization configuration method for improving the transient voltage safety of a regional power grid according to claim 2 is characterized in that: The dynamic model constraints of the static synchronous compensator are: Among them, I si is the injection current amplitude of the static synchronous compensator control node i; U srefi K is the voltage reference value of the static synchronous compensator control node i; p , X T and T s is the gain factor, equivalent reactance and time constant of the static synchronous compensator controller; S base k is the configuration capacity base value of the static synchronous compensator; sti is an integer variable, indicating that the configuration capacity of the static synchronous compensator is a multiple of the base value; V i is the node voltage amplitude of the static synchronous compensator control node i; V xi and V yi is the real and imaginary part of the voltage at node i; I sxi and I syi The real and imaginary parts of the current injected into the static synchronous compensator control node i; The dynamic model constraints of the grid-connected inverter are: Among them, θ Gi and ω Gi is the power angle and angular velocity of the grid-connected inverter at node i; ω N and ω s are the synchronous angular velocity and the reference angular velocity; E i is the internal potential of the grid-connected inverter at node i; D n and D q is the inverse of the damping and amplifier gain factor; G m and B m is the equivalent conductance and susceptance; J is the inertia time constant of the control link. Ti , Q Ti and E i * are the active power reference value, reactive power reference value and potential reference value of the grid-connected inverter at node i respectively. vxi_out and I vyi_out are the real and imaginary parts of the output current of the new energy station using the grid-type control node i; The current limiting constraint of the grid-connected inverter is: Among them, I vxi ,I vyi and I vi I is the real part, imaginary part and amplitude of the grid current injected into the new energy station using the grid-type control node i; vi_out is the output current amplitude of the new energy station using the grid-type control node i, I vi_max For I vi The maximum value of The dynamic model constraints of the grid-following inverter are: Among them, θ PLLi and ω PLLi It is the output power angle and output angular velocity of the phase-locked loop in node i of the new energy station that adopts grid-following control; I edi and I eqi are the d-axis and q-axis components of the phase-locked loop output current; K p and K i is the parameter of the PI control loop in the phase-locked loop; R g and L g is the equivalent resistance and inductance of the grid-side transformer; k 1i , k 2i , k 3i , k 4i and M i is the intermediate parameter of node i and network type control. Pi and x Qi It is the state quantity introduced to control the output active power and reactive power of renewable energy; P emi and Q emi is the active and reactive power output by the converter of the new energy station under the control of the phase-locked loop; P erefi and Q erefi YesP emi and Q emi Reference setting value; P ei and Q ei is the active and reactive power injected by the new energy station into the grid node i under the control of the phase-locked loop; K pgd and K igd is the parameter in the active power PI control loop; K pgq and K igq is the parameter in the reactive power PI control loop; I gxi and I gyi The real and imaginary parts of the grid current injected into the new energy station using the grid-following control node i; The dynamic model constraints of the synchronous generator are: Among them, δ i and ω i is the power angle and angular velocity of the synchronous generator at node i; E qi ' and E fi is the transient potential and excitation potential of the synchronous generator at node i; qi and i di are the quadrature-axis current and direct-axis current of the synchronous generator at node i; D i and P Ti is the damping and mechanical power of the synchronous generator at node i; X di and X di ' is the d-axis reactance and transient d-axis reactance of the synchronous generator at node i; T Ji , T d0i '、T E and K A is the inertia time constant, transient open circuit time constant, excitation winding time constant and amplification factor of the synchronous generator at node i; di and i qi is the d-axis and q-axis current amplitude output by the synchronous generator at node i; V di and V qi I is the d-axis and q-axis voltage amplitude of the synchronous generator at node i; xi and I yi is the real and imaginary parts of the grid current injected into node i; G xi , B xi , B yi , G yi is the admittance of generator i and its salient pole effect into the network, which are its parameters R ai , X di , X di ′、X qi and power angle δ i Function of The dynamic model constraints for conventional loads are: Among them, e xi ' and e yi ' is the real and imaginary parts of the transient potential of the induction motor at node i, s i is the slip rate of the induction motor at node i, T' d0l is the decay time constant of the transient potential, r 1i 、x i and x i ' is the stator resistance, synchronous reactance and transient reactance of the induction motor at node i, T JL is the rotor inertia time constant, K L is the load rate, a is the percentage of the mechanical load that is not related to the speed, n p is the load index; K Hi is the capacity conversion ratio of the induction motor at node i, that is, the ratio of the system capacity base value to the capacity base value of the induction motor at node i; The dynamic model constraints for impact loads are: Among them, K Hi (t), r 1i (t) and x i ′(t) is the time-varying dynamic parameter identified by the historical measured data-driven method of the impact load startup process of node i; The network operation constraints are: Among them, P Gi and Q Gi P is the active and reactive power output of the synchronous generator in steady state; ei and Q ei P is the active and reactive power output of the renewable energy station in steady state; Li and Q Li I is the active and reactive loads in steady state of normal load and impact load; si0 is the current amplitude injected into the node by STATCOM; V i0 ,V xi0 ,V yi0 is the voltage amplitude of node i and its corresponding rectangular coordinate component in steady state; G ij and B ij is the mutual conductance and mutual susceptance between nodes i and j; The transient voltage safety constraints are: V imin ≤V i (t)≤V imax ; Among them, V i is the voltage amplitude of bus i, Vi min The lower limit of the voltage safe operating range, Vi max The upper limit of the safe operating range of voltage.

4. The coordinated optimization configuration method for improving the transient voltage safety of a regional power grid according to claim 1 is characterized in that: The Lagrange interpolation method is used to rewrite the grid-type inverter current limiting constraint into a polynomial interpolation function, including: Setting a plurality of anchor points for the current limiting constraint of the grid-connected inverter; The Lagrange interpolation method is used to calculate the polynomial interpolation function passing through the plurality of anchor points.

5. The coordinated optimization configuration method for improving the transient voltage safety of a regional power grid according to claim 1 is characterized in that: The polynomial interpolation function is: Among them, λ vi1 , vi2 , vi3 , vi4 are the four terms of Lagrange interpolation; I viN For I vi The five anchor points are (0,0), (I N ,I N )、(I max ,I max )、(1.25I max ,I max ) and (1.5I max ,I max ).

6. The coordinated optimization configuration method for improving the transient voltage safety of a regional power grid according to claim 1 is characterized in that: The compact form of the coordinated optimization configuration model is: Among them, x and y are optimization variables.

7. The coordinated optimization configuration method for improving the transient voltage safety of a regional power grid according to claim 6 is characterized in that: The nonlinear algebraic equation of the differential equation constraint in the compact form of the coordinated optimization configuration model is: Where h is the step size of a single period set by the implicit trapezoidal method.

8. A coordinated optimization configuration device for improving the transient voltage safety of a regional power grid, characterized in that: include: A model building module is used to build a coordinated optimization configuration model with the sum of the installation cost of the static synchronous compensator and the reconstruction cost of the grid-type inverter as the objective function, and with the dynamic model constraints of the static synchronous compensator, the dynamic model constraints of the grid-type inverter, the current limiting constraints of the grid-type inverter, the dynamic model constraints of the grid-following inverter, the dynamic model constraints of the synchronous generator, the dynamic model constraints of the conventional load, the dynamic model constraints of the impact load, the network operation constraints and the transient voltage safety constraints as constraints, wherein the current limiting constraints of the grid-type inverter are piecewise function constraints; A model rewriting module, used for rewriting the coordinated optimization configuration model into a compact coordinated optimization configuration model; A constraint conversion module, used for converting the differential equation constraints in the compact form coordinated optimization configuration model into nonlinear algebraic equations; A function rewriting module, used to rewrite the current limiting constraint of the grid-type inverter into a polynomial interpolation function by using a Lagrange interpolation method, and to approximate the current limiting constraint of the grid-type inverter by using the polynomial interpolation function; The model solving module is used to solve the transformed compact coordinated optimization configuration model to obtain an optimized configuration solution.

9. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the coordinated optimization configuration method for improving the transient voltage safety of the regional power grid as described in any one of claims 1-7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, a coordinated optimization configuration method for improving the transient voltage safety of a regional power grid is implemented as described in any one of claims 1-7.

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