Converter station parameter determination method and device for improving transient voltage stability

Abstract

The invention provides a method and a device for determining converter station parameters for improving transient voltage stability, which can be applied to the technical field of automatic configuration of a hybrid power grid. The method comprises the steps of obtaining a critical stable voltage parameter of a dynamic load associated with a converter station according to a mechanical torque and an electromagnetic torque of a dynamic charge corresponding to a critical stable state and a rotor motion equation; according to the bus voltage parameters of the converter station in different stages and the critical stable voltage parameters of the associated dynamic load, constructing a stability sub-objective function for representing the transient voltage stability of the target system; an economic cost sub-objective function of the target system is constructed according to the respective installation positions and capacities of the different phase modifiers in the plurality of converter stations in the target system; according to the critical stable voltage parameter, constructing a reactive compensation constraint and a bus voltage stability constraint of the target system; and solving the optimal configuration combination of the phase modifier, and outputting respective target configuration parameters of the plurality of converter stations.

Description

Technical Field

[0001] The present invention relates to the technical field of automated configuration of hybrid power grids, and more particularly to a method and device for determining converter station parameters for improving transient voltage stability. Background Art

[0002] With the rapid development of ultra-high voltage direct current (UHVDC) transmission systems, receiving-end power grids are adopting hybrid AC / DC characteristics with multiple DC infeeds. Consequently, receiving-end power grids simultaneously carry large amounts of reactive power (hereinafter referred to as reactive) loads and renewable energy sources, and face the risks of low-inertia operation and commutation failure, making the system susceptible to transient voltage instability when subjected to disturbances.

[0003] In the process of realizing the concept of the present invention, it was found through research that the reactive power supplementation method in the related art is difficult to meet the large-scale transient support demand, resulting in low transient voltage stability of the system. Summary of the Invention

[0004] In view of this, the present invention provides a method and apparatus for determining converter station parameters for improving transient voltage stability.

[0005] One aspect of the present invention provides a method for determining converter station parameters for improving transient voltage stability, wherein the converter station includes a phase regulator, and the method comprises:

[0006] Based on the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state, and the rotor motion equation for the transition from rated operating conditions to critical stable state conditions, the critical stable voltage parameters of the dynamic load associated with the converter station are obtained; based on the bus voltage parameters when the converter station is in different stages and the critical stable voltage parameters of the associated dynamic load, a stability sub-objective function is constructed to characterize the transient voltage stability of the target system, and based on the respective installation positions and capacities of different phase regulators in multiple converter stations in the target system, an economic cost sub-objective function of the target system is constructed, where the different stages include sub-transient stage, transient stage, and post-fault removal recovery stage; based on the critical stable voltage parameters, the reactive compensation constraints and bus voltage stability constraints of the target system are constructed; based on the stability sub-objective function, economic cost sub-objective function, reactive compensation constraints and bus voltage stability constraints, the optimal configuration combination of the phase regulators is solved, and the target configuration parameters of multiple converter stations in the target system are output.

[0007] Another aspect of the present invention provides a device for determining converter station parameters for improving transient voltage stability, comprising:

[0008] An obtaining module obtains a critical stable voltage parameter of the dynamic load associated with the converter station based on the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state and the rotor motion equation for transition from the rated operating condition to the critical stable state operating condition;

[0009] A function construction module is used to construct a stability sub-objective function for characterizing the transient voltage stability of the target system based on the bus voltage parameters and the critical stability voltage parameters of the associated dynamic loads when the converter station is in different stages, and to construct an economic cost sub-objective function for the target system based on the respective installation locations and capacities of different phase regulators in multiple converter stations in the target system. The different stages include a sub-transient stage, a transient stage, and a post-fault clearing recovery stage.

[0010] A constraint construction module is used to construct reactive compensation constraints and bus voltage stability constraints of the target system based on critical stable voltage parameters;

[0011] The solution module is used to solve the optimal configuration combination of the phase regulator based on the stability sub-objective function, economic cost sub-objective function, reactive power compensation constraint and bus voltage stability constraint, and output the target configuration of multiple converter stations in the target system.

[0012] Another aspect of the present invention provides an electronic device, comprising:

[0013] one or more processors;

[0014] a memory for storing one or more programs,

[0015] When the one or more programs are executed by the one or more processors, the one or more processors implement the method as described above.

[0016] According to an embodiment of the present invention, a stability sub-objective function is constructed based on the bus voltage parameters and critical stable voltage parameters of the converter station during the sub-transient, transient, and post-fault clearing recovery phases. A phase-shifting economic cost sub-objective function is also constructed. The target configuration parameters are determined based on the critical stable voltage parameters of the dynamic load, the reactive compensation constraints of the target system, and the bus voltage stability constraints. Compared to traditional reactive support methods that only consider the single case of commutation failure, this method couples the different time scales corresponding to the three phases of the transient process, fully accounting for bus voltage variations at each stage of the transient process. Simultaneously, the optimal phase-shifting configuration model is solved by combining the critical stable voltage parameters of the dynamic load, the reactive compensation constraints of the target system, the bus voltage stability constraints, and the phase-shifting economic cost sub-objective function. This ensures that the reactive compensation achieved by the target configuration parameters meets reactive power requirements while maintaining a certain level of reliability and economy. Therefore, configuring phase-shifting converters at the converter station according to the target configuration parameters is beneficial for achieving maximum phase-shifting efficiency while improving the transient voltage stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.

[0018] Figure 1 A schematic structural diagram of a receiving-end power grid of a multi-infeed DC system according to an embodiment of the present invention is shown.

[0019] Figure 2 A flow chart of a method for determining converter station parameters for improving transient voltage stability according to an embodiment of the present invention is shown.

[0020] Figure 3 Shown Figure 1 The topological structure diagram of the power grid is shown.

[0021] Figure 4 A schematic diagram showing the coupling relationship between the economic cost sub-objective function and the stability sub-objective function according to an embodiment of the present invention is shown.

[0022] Figure 5a The waveform of the bus voltage of the BA converter station changing with time after a three-phase short circuit fault occurs at the fault point A according to an embodiment of the present invention is shown.

[0023] Figure 5b The waveform of the bus voltage of the DF converter station changing with time after a three-phase short circuit fault occurs at the fault point A according to an embodiment of the present invention is shown.

[0024] Figure 5c The waveform of the bus voltage of the BA converter station changing with time after a three-phase short circuit fault occurs at the fault point B according to an embodiment of the present invention is shown.

[0025] Figure 5d The waveform of the bus voltage of the DF converter station changing with time after a three-phase short circuit fault occurs at the fault point B according to an embodiment of the present invention is shown.

[0026] Figure 6a The waveform of the target system node voltage changing over time under the rated power conversion operation mode according to an embodiment of the present invention is shown.

[0027] Figure 6b The waveform of the target system node voltage changing with time under the DC filter switching condition according to an embodiment of the present invention is shown.

[0028] Figure 6c The waveform of the target system node voltage changing with time under a commutation failure condition according to an embodiment of the present invention is shown.

[0029] Figure 6d The waveform of the target system node voltage changing with time under a short-circuit fault condition according to an embodiment of the present invention is shown.

[0030] Figure 7a The waveforms of reactive power compensation and reactive power demand changing over time for different phase-shifting configuration combinations according to an embodiment of the present invention are shown.

[0031] Figure 7b The waveforms showing the change of slip over time for different phase regulator configuration combinations according to an embodiment of the present invention are shown.

[0032] Figure 8 A block diagram of a device for determining converter station parameters for improving transient voltage stability according to an embodiment of the present invention is shown.

[0033] Figure 9 A block diagram of an electronic device suitable for implementing a method for determining converter station parameters for improving transient voltage stability according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0034] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0035] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0036] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0037] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0038] During the implementation of the present invention, research revealed the following: As a key component of hybrid AC / DC power grids, converters consume significant amounts of reactive power during commutation. Therefore, converter stations are typically equipped with reactive power compensation devices, such as static var compensators (SVCs). In normal operation of a multi-input DC system, the reactive power provided by the reactive power compensation devices roughly equals the reactive power consumed by the converters. However, under fault conditions, regardless of whether commutation fails or succeeds, the system requires significant reactive power during the transition from transient to steady-state, and this reactive power consumption continues for a significant period after the fault is cleared.

[0039] However, in the related art, the reactive compensation provided by the reactive compensation equipment in the converter station is proportional to the square of its bus voltage. Therefore, in the event of an AC fault, the reduction in bus voltage will cause the reactive compensation output by reactive compensation equipment such as SVC to be significantly reduced. The reactive compensation required by the transient process system is higher than that during normal operation. Therefore, relying solely on existing reactive compensation equipment to provide reactive compensation is difficult to meet the transient reactive requirements of the system, making it difficult for the system to quickly restore the transient stable voltage after a fault condition.

[0040] In view of this, an embodiment of the present invention provides a method for determining converter station parameters for improving transient voltage stability, including: obtaining critical stability voltage parameters of the dynamic load associated with the converter station based on the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stability state, and the rotor motion equation for transitioning from rated operating conditions to critical stability state conditions; constructing a stability sub-objective function for characterizing the transient voltage stability of the target system based on the bus voltage parameters when the converter station is in different stages and the critical stability voltage parameters of the associated dynamic load, and constructing an economic cost sub-objective function of the target system based on the respective installation positions and capacities of different phase regulators in multiple converter stations in the target system, wherein the different stages include sub-transient stage, transient stage, and post-fault removal recovery stage; constructing reactive compensation constraints and bus voltage stability constraints of the target system based on the critical stability voltage parameters; solving the optimal configuration combination of the phase regulator based on the stability sub-objective function, the economic cost sub-objective function, the reactive compensation constraints and the bus voltage stability constraints, and outputting the target configuration parameters of each of the multiple converter stations in the target system.

[0041] According to an embodiment of the present invention, the converter station includes a phase regulator and a converter. The phase regulator is used to provide reactive power compensation for the system based on the traditional reactive power compensation equipment. In order to better understand the application scenarios applicable to the determination method of the embodiment of the present invention, the following will be combined with Figure 1 , the overall architecture of the multi-infeed DC system is explained.

[0042] Figure 1 A schematic structural diagram of a receiving-end power grid of a multi-infeed DC system according to an embodiment of the present invention is shown.

[0043] like Figure 1 As shown in the figure, the receiving-end grid of a MIDC system includes multiple substations (MM, CH, ZJ, PC, and SZ) connected by AC lines and multiple UHV converter stations (CX, LM, BA, and DF). The UHVDC lines (NC, LL, JZ, and XD) are connected to the multiple UHV converter stations for DC transmission. The multiple UHV converter stations convert DC voltage to AC voltage, which is then transmitted via AC lines to multiple substations for distribution. This power is then supplied to multiple consumers, including dynamic loads such as induction motors. The reactive or active power demand of these dynamic loads can alter the busbar voltage at the converter stations, affecting their transient voltage stability.

[0044] Figure 2 A flow chart of a method for determining converter station parameters for improving transient voltage stability according to an embodiment of the present invention is shown.

[0045] like Figure 2 As shown, the method 200 includes operations S210 to S240.

[0046] In operation S210 , a critical stable voltage parameter of the dynamic load associated with the converter station is obtained based on the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state and a rotor motion equation transitioning from the rated operating condition to the critical stable state operating condition.

[0047] According to an embodiment of the present invention, the critical stable voltage parameter of the dynamic load represents the minimum voltage threshold required to maintain stable operation of the dynamic load. The bus voltage parameter at the converter station at any time after a fault must be greater than the critical stable voltage parameter of the dynamic load. In other words, the critical stable voltage parameter of the dynamic load is the minimum threshold of the bus voltage parameter.

[0048] According to an embodiment of the present invention, taking an induction motor as an example of a dynamic load, mechanical torque drives the rotor to rotate, causing relative motion of the magnetic field, which triggers electromagnetic induction and generates an electric potential difference. The electromagnetic torque, in turn, aids in the continued rotation of the rotor through the relative motion of the magnetic field. Together, these two forces maintain the stable operation of the induction motor and ensure continuous power output.

[0049] According to an embodiment of the present invention, in a critical stable state, the electromagnetic torque is balanced with the mechanical torque, that is, the electromagnetic power is equal to the mechanical power.

[0050] In operation S220, a stability sub-objective function for characterizing the transient voltage stability of the target system is constructed based on the bus voltage parameters when the converter station is in different stages and the critical stability voltage parameters of the associated dynamic loads, and an economic cost sub-objective function of the target system is constructed based on the respective installation locations and capacities of different phase regulators in multiple converter stations in the target system.

[0051] According to an embodiment of the present invention, the different phases include, in sequence, a subtransient phase, a transient phase, and a post-fault recovery phase. The subtransient phase of the phase regulator is primarily driven by the damping winding. After the damping winding experiences dynamic attenuation, the phase regulator enters a transient phase, primarily driven by the excitation winding and the excitation regulator. The post-fault recovery phase occurs after the fault is cleared, where strong excitation overcomes the limitations of the transient time constant and provides continuous and efficient reactive power support, accelerating voltage recovery.

[0052] According to an embodiment of the present invention, the stability sub-objective function can be used to characterize the functional relationship between the transient voltage stability margin of each converter station in the target system and the change of bus voltage parameters, wherein the target system can be a multi-infeed DC system.

[0053] According to an embodiment of the present invention, based on the UHV AC / DC hybrid power grid topology at the receiving end of the multi-infeed DC system, converter station data, candidate phase-shifting model parameters and economic parameters, dynamic load access ratio and parameters, and other data and parameters related to economic planning, a phase-shifting economic cost sub-objective function as shown in the following formula (1) is constructed: .

[0054] (1);

[0055] Among them, the economic cost sub-objective function of the condenser The economic cost of multiple converter stations is a function of the total capacity of the phase-shifting units in each converter station. The function value of is the minimum to configure the target commutator. n is the total number of converter stations in the target system, represents the initial cost of the i-th converter station. The initial cost includes the equipment land acquisition cost, equipment transportation, construction and installation cost, and equipment purchase cost. The purchase cost and operation and maintenance cost of the same equipment are roughly the same, but the cost will vary slightly due to slight differences in land acquisition costs and transportation costs in different locations. Indicates the operation and maintenance cost of the unit capacity phase regulator during the entire life cycle, represents the total capacity of the phase-converter installed in the i-th converter station. The purchase cost and operation and maintenance costs of the same equipment are roughly the same, but the costs may vary slightly due to slight differences in land acquisition costs and transportation costs in different locations.

[0056] According to an embodiment of the present invention, a single converter station includes multiple installation points for phase regulators. For example, a CX converter station includes four installation points. For fixed-capacity phase regulators, the number of installation points varies. The function values ​​are different.

[0057] In operation S230 , reactive power compensation constraints and bus voltage stability constraints of the target system are constructed according to the critical stable voltage parameters.

[0058] According to an embodiment of the present invention, the reactive compensation constraint represents the minimum reactive compensation required by the converter station, and serves as a constraint condition when subsequently determining the target configuration parameters, ensuring that the obtained target configuration parameters can meet the reactive compensation required by the converter station after a fault while meeting economic needs.

[0059] According to an embodiment of the present invention, bus voltage stability constraints may be constructed according to specifications adopted in actual needs.

[0060] In operation S240, based on the stability sub-objective function, the economic cost sub-objective function, the reactive power compensation constraint and the bus voltage stability constraint, the optimal configuration combination of the phase regulator is solved, and the target configuration parameters of each of the multiple converter stations in the target system are output.

[0061] According to an embodiment of the present invention, the optimal configuration model of the phase regulator can be constructed with the goal of maximizing the function value of the stability sub-objective function and minimizing the function value of the economic cost sub-objective function of the target system. Based on the reactive compensation constraint and the bus voltage stability constraint, the particle swarm optimization algorithm can be used to solve the optimal configuration combination of the phase regulator and output the target configuration parameters of the converter station.

[0062] According to an embodiment of the present invention, a stability sub-objective function is constructed based on the bus voltage parameters and critical stability voltage parameters of the converter station during the sub-transient, transient, and post-fault clearing recovery phases. A phase-shifting economic cost sub-objective function is also constructed. Target configuration parameters are determined based on the critical stability voltage parameters of the dynamic load, the reactive compensation constraints of the target system, and the bus voltage stability constraints. Compared to traditional reactive support methods that only consider the single case of commutation failure, this method couples the different time scales corresponding to the three phases of the transient process, fully accounting for bus voltage variations at each stage of the transient process. Simultaneously, the optimal phase-shifting configuration model is solved by combining the critical stability voltage parameters of the dynamic load, the reactive compensation constraints of the target system, the bus voltage stability constraints, and the phase-shifting economic cost sub-objective function. This ensures that the reactive compensation achieved by the target configuration parameters meets reactive power requirements while maintaining a certain level of reliability and economy. Therefore, configuring phase-shifting systems at the converter station according to the target configuration parameters is beneficial for achieving maximum phase-shifting efficiency while improving the transient voltage stability of the system.

[0063] According to an embodiment of the present invention, a stability sub-objective function for characterizing the transient voltage stability of the target system is constructed based on the bus voltage parameters when the converter station is in different stages and the critical stability voltage parameters of the associated dynamic loads, and an economic cost sub-objective function of the target system is constructed based on the respective installation positions and capacities of different phase regulators in multiple converter stations in the target system, including: constructing a stability sub-objective function based on the integral of the differences between the bus voltage parameters and the critical stability voltage parameters of the multiple converter stations in the sub-transient stage, the transient stage and the recovery stage after fault removal; constructing an economic cost sub-objective function based on the respective installation positions and capacities of different phase regulators in multiple converter stations.

[0064] According to an embodiment of the present invention, the stability sub-objective function It can be expressed as the following formula (2).

[0065] (2);

[0066] in, represents the transient voltage stability margin of the i-th converter station, represents the bus voltage parameter of the i-th converter station at time t, represents the critical stable voltage parameter of the busbar at the i-th converter station, t0 represents the starting time of the subtransient stage, t1 represents the ending time of the subtransient stage and the starting time of the transient stage, t2 represents the ending time of the transient stage and the starting time of the recovery stage after fault removal, and t3 represents the ending time of the recovery stage after fault removal.

[0067] According to an embodiment of the present invention, the stability of the target system is constrained by the stability sub-objective function, and the economic cost of the target system is constrained by the economic cost sub-objective function. The performance and cost of the target system are taken into consideration in a coordinated manner, thereby avoiding the problem that the target configuration parameters obtained have high transient voltage stability but excessively high costs.

[0068] Figure 3 Shown Figure 1 The topological structure diagram of the power grid is shown.

[0069] like Figure 3 As shown, the 500kV bus connects the converter 310, SVC 320, and phase regulator 330. Taking the 500kV bus and the 10kV bus as an example, the 500kV bus and the 10kV bus are connected via a transformer 350 and an equivalent impedance 340, and the 10kV bus connects the dynamic load 360 and the AC system 370.

[0070] Inverter 310, connected to the input power supply, consumes a large amount of reactive power during a fault, making commutation failure a likely occurrence and causing a bus voltage crash. The reactive power compensation provided by SVC 320 is proportional to the square of the bus voltage, so the reactive power provided during a fault cannot meet demand. Therefore, reactive power compensation can be provided by properly configuring the capacity and number of phase-converters 330 to support transient voltages. During a fault, the voltage drop on the 500kV bus is transmitted to the 10kV bus through transformer 350 and equivalent impedance 340. Dynamic load 360 is sensitive to voltage fluctuations, and its motor is prone to stalling when the bus voltage drops, further lowering the voltage and exacerbating the risk of voltage collapse.

[0071] According to an embodiment of the present invention, based on the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state, and the rotor motion equation for transition from the rated operating condition to the critical stable state, the critical stable voltage parameters of the dynamic load associated with the converter station are obtained, including: constructing a torque balance equation based on the mechanical torque and electromagnetic torque corresponding to the critical stable state; and combining the torque balance equation and the rotor motion equation to obtain the critical stable voltage parameters of the dynamic load associated with the converter station.

[0072] According to an embodiment of the present invention, the mechanical torque T k The relationship with the slip s can be expressed as the following formula (3).

[0073] (3);

[0074] Among them, P k represents mechanical power, Ω represents the mechanical angular velocity of rotation, k L It represents the load rate of dynamic load, and a represents the power characteristic coefficient.

[0075] According to an embodiment of the present invention, the electromagnetic torque T e The relationship with the slip s can be expressed as the following formula (4).

[0076] (4);

[0077] Among them, P e Indicates mechanical power, S M Indicates dynamic load capacity, S ac Indicates the short-circuit capacity of the AC system, X w Stator reactance representing dynamic load, X r The rotor reactance representing the dynamic load, R r The rotor resistance representing the dynamic load.

[0078] According to an embodiment of the present invention, since the mechanical torque and the electromagnetic torque are equal in the critical stable state, the torque balance equation can be obtained by combining the above formula (3) and formula (4).

[0079] According to an embodiment of the present invention, the rotor motion equation can be expressed as the following formula (5).

[0080] (5);

[0081] Among them, T r represents the rotor inertia time constant, t cr It represents the moment of fault clearing, s1 represents the slip under rated working condition, and s3 represents the slip under critical stable working condition.

[0082] According to an embodiment of the present invention, the converter station also includes a static VAR compensator and a converter. Based on critical stable voltage parameters, reactive compensation constraints and bus voltage stability constraints for the target system are established, including: obtaining rated parameters of the converter and static VAR compensator, respectively; obtaining the rated reactive output of the static VAR compensator and the reactive consumption threshold of the converter based on the rated parameters; and establishing the reactive compensation constraints for the target system based on the rated reactive output and the reactive consumption threshold.

[0083] According to an embodiment of the present invention, constructing the reactive compensation constraints of the target system based on the rated reactive output and reactive consumption thresholds includes: constructing the reactive compensation constraints of multiple converter stations based on the rated reactive output and reactive consumption thresholds; constructing the reactive compensation constraints of the target system based on the reactive compensation constraints of multiple converter stations.

[0084] According to the embodiment of the present invention, the phase regulator has no active load, the power angle δ≈0, and most phase regulators are non-salient pole structures, so the active power P of the phase regulator is SC and reactive power Q SC They can be expressed as the following formulas (6) and (7) respectively.

[0085] (6);

[0086] (7);

[0087] Among them, u d represents the d-axis voltage, i d represents the d-axis current, u q represents the q-axis voltage, i q represents the q-axis current, E q represents the q-axis electromotive force, X d Indicates the d-axis reactance, U bus Indicates the equivalent bus voltage. Without considering the excitation regulation, the q-axis voltage drop value of the phase regulator after the system failure ,u q0 Indicates the q-axis voltage and d-axis voltage drop value before the fault ,u d0 represents the d-axis voltage before the fault. Therefore, the d-axis flux and q-axis magnetic flux They can be expressed as the following formulas (8) and (9) respectively.

[0088] (8);

[0089] (9);

[0090] Where r represents the stator resistance and p is the complex variable of Laplace transform. Combining formula (8) and formula (6), the change of d-axis current is After performing the inverse Laplace transform and superimposing the steady-state components, we can obtain the following formula (10): The time domain expression of .

[0091] (10);

[0092] in, It can represent the d-axis subtransient reactance, It can express the d-axis subtransient short-circuit time constant; represents the d-axis transient reactance, Indicates the d-axis transient short-circuit time constant, T a represents the time constant of the stator non-periodic component, Indicates the bus voltage drop value.

[0093] According to an embodiment of the present invention, the reactive power compensation of the phase regulator in the sub-transient stage It can be expressed as the following formula (11).

[0094] (11);

[0095] Among them, U s0 Indicates the voltage before disturbance, U s1 It can be seen from this that the output of the phase regulator in the sub-transient stage includes The constant attenuation AC component, the steady-state component, the damping winding caused by The subtransient component with constant decay and the one caused by the excitation winding is a transient component with a constant decay. Therefore, the reactive power compensation provided by the condenser during the subtransient phase is proportional to the bus voltage drop, unlike the SVC, where reactive power compensation is proportional to the square of the bus voltage. Therefore, the greater the bus voltage drop, the more reactive power the condenser provides during the subtransient phase, effectively preventing DC commutation failure.

[0096] According to an embodiment of the present invention, the q-axis transient potential of the phase regulator in the transient stage It can be expressed as the following formula (12).

[0097] (12).

[0098] According to an embodiment of the present invention, the imaginary no-load potential change and The relationship can be expressed as the following formula (13).

[0099] (13).

[0100] According to an embodiment of the present invention, the reactive power compensation of the phase regulator in the transient stage It can be expressed as the following formula (14).

[0101] (14);

[0102] in, is the excitation system boost factor. Therefore, excitation system boost control increases the reactive power compensation of the phase regulator. It takes approximately 0.06 seconds for the excitation system to reach its maximum boost factor. Therefore, the period from the fault occurrence to 0.06 seconds corresponds to the subtransient phase. The system then enters the transient phase, dominated by excitation control. Under boost, reactive power compensation can continuously support the bus voltage.

[0103] Based on this, for the i-th converter station, the reactive power compensation of the SVC and the phase regulator in the sub-transient stage must exceed the reactive power consumption threshold of the converter. , therefore, the reactive power compensation constraint of the i-th converter station can be expressed as the following formula (15).

[0104] (15);

[0105] in, represents the reactive exchange of the i-th converter station, represents the rated reactive output of the SVC installed in the i-th converter station, m i represents the number of phase regulators installed in the i-th converter station, n i represents the number of converters installed in the i-th converter station.

[0106] According to an embodiment of the present invention, based on the above formula (15), the reactive power compensation constraint of the target system shown in the following formula (16) can be obtained.

[0107] (16).

[0108] According to an embodiment of the present invention, reactive compensation constraints and bus voltage stability constraints of a target system are constructed based on critical stable voltage parameters, including: constructing a first bus voltage constraint based on the critical stable voltage parameters so that the bus voltage parameters at different stages are all greater than the critical stable voltage parameters; obtaining the rated voltage parameters of the converter station before the fault; and constructing a second bus voltage constraint based on the rated voltage parameters of the converter station before the fault and multiple predetermined constraint multiples corresponding to multiple target moments, wherein the target moment is any moment within the different stages.

[0109] According to an embodiment of the present disclosure, the bus voltage stability constraint includes a first bus voltage constraint and a second bus voltage constraint. To prevent system voltage collapse due to insufficient dynamic electromagnetic torque and a large number of stalls in the UHV AC / DC hybrid system during a fault, it is necessary to ensure that the bus voltage parameters of each converter station are greater than the critical stability voltage parameters at different stages after the fault. Therefore, the first bus voltage constraint can be constructed.

[0110] According to an embodiment of the present invention, the predetermined constraint multiple may be set according to requirements of technical specifications followed in actual application.

[0111] For example, the second bus voltage constraint can be expressed as the following formula (17).

[0112] (17);

[0113] The target times are t0+1, t0+10, and t0+60, and the predetermined constraint multiples corresponding to the target times are 0.75, 0.8, and 0.9. t0 represents the time when the fault occurs. represents the bus voltage of the i-th converter station before the fault, represents the second bus voltage constraint corresponding to the target time (t0+1), represents the second bus voltage constraint corresponding to the target time (t0+10), represents the second bus voltage constraint corresponding to the target time (t0+60).

[0114] It can be seen from this that for the i-th converter station, the bus voltage parameter at the time t0+1 must be greater than 0.75 times , the bus voltage parameter at the time t0+10 must be greater than 0.8 times , the bus voltage parameter at the time t0+60 must be greater than 0.9 times .

[0115] According to an embodiment of the present invention, integrating the rated parameters of converters and static VAR compensators to construct reactive compensation constraints improves the accuracy of transient reactive power balance. Both busbar voltage stability constraints and reactive compensation constraints utilize a hierarchical approach, first establishing constraints at a single converter station and then aggregating them into system-level constraints. This avoids cascading failures caused by insufficient local reactive power compensation and lays a foundation for transient voltage stability in the UHV power grid.

[0116] According to an embodiment of the present invention, based on the stability sub-objective function, the economic cost sub-objective function, the reactive power compensation constraint and the bus voltage stability constraint, the optimal configuration combination of the phase regulator is solved, and the target configuration parameters of multiple converter stations in the target system are output, including: constructing the target configuration function of the target system according to the Euclidean distance between the stability sub-objective function and the economic cost sub-objective function; determining multiple candidate phase regulator configuration combinations according to the target configuration function, the reactive power compensation constraint and the bus voltage stability constraint; solving the optimal configuration combination of the phase regulator according to the multiple candidate phase regulator configuration combinations, and outputting the respective target configuration parameters of multiple converter stations in the target system.

[0117] According to an embodiment of the present invention, the Euclidean distance between the two sub-objective functions can be used to normalize the objective sub-function into a single objective configuration function, so that the subsequent solution can simultaneously achieve the optimality of the two sub-objective functions. The objective configuration function F can be expressed as the following formula (18).

[0118] (18);

[0119] Where M represents all candidate phase-shifting configuration combinations, x represents any candidate phase-shifting combination in M, represents the solution set in M ​​that can achieve the minimum function value of the economic cost sub-objective function in the above formula (1), It represents the solution set with the largest function value in M ​​that can achieve the stability sub-objective function in the above formula (2).

[0120] According to an embodiment of the present invention, based on the rated parameters obtained above, the target system can be simulated to obtain a simulation model, and the target configuration function can be solved using a particle swarm optimization algorithm to obtain the optimal configuration combination of the phase regulator.

[0121] According to an embodiment of the present invention, based on a plurality of candidate phase modulator configuration combinations, the optimal phase modulator configuration combination is solved, and the respective target configuration parameters of a plurality of converter stations in the target system are output, including: obtaining the target total capacity of the target system based on the reactive power compensation constraint of the converter station, the bus voltage stability constraint and the proportional parameter of the dynamic load; based on the target total capacity, determining a plurality of target phase modulator configuration combinations from a plurality of candidate phase modulator configuration combinations.

[0122] Figure 4 A schematic diagram showing the coupling relationship between the economic cost sub-objective function and the stability sub-objective function according to an embodiment of the present invention is shown.

[0123] like Figure 4 As shown in the figure, the horizontal axis represents the transient voltage stability margin (in pu·s (per-unit seconds)), and the vertical axis represents the economic cost corresponding to the economic cost sub-objective function (in 100 million yuan). This shows that at least four phase regulators are required to meet the transient stability requirements of the target system's AC / DC hybrid power grid. Furthermore, as the phase regulator capacity increases, the economic cost increases linearly, while the increase in the transient voltage stability margin gradually slows. Therefore, blindly incurring excessive economic costs to improve the transient voltage stability margin is unjustified.

[0124] Based on this, the target total capacity of the target system can be determined first, and then the target phase shifter configuration combination can be determined from all candidate phase shifter configuration combinations based on the target total capacity.

[0125] For example, Figure 4The configuration parameters corresponding to the five optimal camera configuration combinations (combination 1 to combination 5) can be expressed as shown in Table 1.

[0126] Table 1

[0127]

[0128] Among them, the installation locations of the phase modulators represent that the locations where a predetermined number of phase modulators are installed are DF converter station, CX converter station, BA converter station and LM converter station. Therefore, it can be seen that the target total capacity can be determined as 1500MVar.

[0129] Table 1 shows that the greatest demand for phase-shifting devices in the DF converter station is due to the weak AC grid strength and the large number of dynamic loads in the area where the DF converter station is located, resulting in poor transient voltage stability. Furthermore, the DF and BA converter stations are close in distance, resulting in a significant interaction factor. Transient voltage fluctuations at the DF converter station have a significant impact on the BA converter station. Therefore, once the upper limit for phase-shifting devices in the DF converter station is reached, prioritization should be given to installing them in the BA converter station.

[0130] Therefore, combination 2, combination 3 and combination 4 are the target phase-shifting machine configuration combinations obtained by screening according to the target total capacity.

[0131] According to an embodiment of the present invention, a target configuration function is solved, and an optimal phase condenser configuration combination is determined from a plurality of target phase condenser configuration combinations, including: sorting the target configuration function values ​​corresponding to each of the plurality of target phase condenser configuration combinations to obtain a sorting result; and determining the optimal phase condenser configuration combination based on the sorting result.

[0132] According to an embodiment of the present invention, the target phase condenser configuration combinations in Table 1 above: combination 2, combination 3 and combination 4 respectively correspond to target configuration function values ​​of 0.355, 0.358 and 0.361. According to the sorting results, combination 2 can be determined as the optimal phase condenser configuration combination.

[0133] In order to verify the accuracy of the method for determining converter station parameters of the present invention, the following Figure 5a to Figure 5d The optimal configuration combination of the phase regulator obtained above was verified, and the first control combination - combination 3 and the second control combination - combination 6 were added.

[0134] Figure 5a The waveform of the bus voltage of the BA converter station changing with time after a three-phase short circuit fault occurs at the fault point A according to an embodiment of the present invention is shown.

[0135] Figure 5b The waveform of the bus voltage of the DF converter station changing with time after a three-phase short circuit fault occurs at the fault point A according to an embodiment of the present invention is shown.

[0136] Figure 5c The waveform of the bus voltage of the BA converter station changing with time after a three-phase short circuit fault occurs at the fault point B according to an embodiment of the present invention is shown.

[0137] Figure 5d The waveform of the bus voltage of the DF converter station changing with time after a three-phase short circuit fault occurs at the fault point B according to an embodiment of the present invention is shown.

[0138] like Figure 5a to Figure 5d As shown in the figure, the horizontal axis represents the time corresponding to different stages after the fault occurs (in seconds), and the vertical axis represents the bus voltage at the converter station (in per unit (pu), reflecting the transient voltage drop and recovery process. Fault point A is located at the 40% point on the line between the CH and ZJ substations, and fault point B is located at the 5% point on the line between the SZ and PC substations.

[0139] according to Figure 5a Combination 2, which installs a 300 MVar condenser in the BA converter station, exhibits significantly better voltage drop and recovery speed than combinations 3 and 6. The waveform in combination 6 indicates that after a DC system fault, there is a significant reactive power deficit in the subtransient and transient phases, meaning reactive power compensation cannot keep up with reactive power consumption. Furthermore, reactive power consumption continues during the recovery phase after fault clearance. Combination 3, which installs a 300 MVar condenser in the LM converter station, exhibits only slightly better waveforms than combination 6. Compared to the waveform in combination 2, transient voltage stability is clearly insufficient.

[0140] according to Figure 5b It can be seen that the waveforms of combination 2 and combination 3 are better than the waveform of combination 6.

[0141] from Figure 5c and Figure 5d It can be found that the waveforms of combination 2 and combination 3 are relatively close, and both can recover to the bus voltage level before the fault. Figure 5d Due to the continuous commutation failure in combination 6, the voltage fluctuates greatly and drops below the critical stable voltage of the dynamic load, which causes the slip of the induction motor in the dynamic load to increase, resulting in motor stalling and transient voltage instability.

[0142] Furthermore, a separate comparison of Combinations 2 and 3 reveals that Combination 2 installs the phase regulator at the BA converter station, while Combination 3 installs the phase regulator at the LM converter station. Therefore, Combination 2 outperforms Combination 3 in terms of bus voltage drop and recovery speed at the BA converter station; conversely, Combination 3 outperforms Combination 2 in terms of bus voltage drop and recovery speed at the LM converter station.

[0143] In order to verify the universality of the method for determining converter station parameters according to the embodiment of the present invention for different working conditions, the following will be Figure 6a to Figure 6d The transient voltage changes under four operating conditions, namely conversion operation mode at rated power, switching DC filter, commutation failure and short circuit fault, are analyzed and compared.

[0144] Figure 6a The waveform of the target system node voltage changing over time under the rated power conversion operation mode according to an embodiment of the present invention is shown.

[0145] Figure 6b The waveform of the target system node voltage changing with time under the DC filter switching condition according to an embodiment of the present invention is shown.

[0146] Figure 6c The waveform of the target system node voltage changing with time under a commutation failure condition according to an embodiment of the present invention is shown.

[0147] Figure 6d The waveform of the target system node voltage changing with time under a short-circuit fault condition according to an embodiment of the present invention is shown.

[0148] like Figure 6a to Figure 6d As shown in the figure, the horizontal axis represents the time corresponding to different stages (in seconds), and the vertical axis represents the node voltage (in pu), which is used to reflect the drop and recovery process of the node voltage over time. Figure 6a and Figure 6b Under the working conditions shown, the installation position of the phase regulator in the converter station does not affect the transient voltage stability, that is, different phase regulator configuration combinations only affect the recovery speed of the node voltage. Figure 6c and Figure 6d Under the working conditions shown, transient voltage instability will occur in combination 6 without a phase regulator installed. Although the phase regulator configuration of combination 3 can just meet the transient voltage stability requirements, the transient voltage stability safety margin is small. Combination 2 has a larger transient voltage stability safety margin, that is, a higher transient voltage stability margin, and therefore has the highest transient voltage support strength.

[0149] According to an embodiment of the present invention, assuming a constant UHVDC transmission power of 5000MW and an AC short-circuit ratio of 2.4, the dynamic load access ratio (hereinafter referred to as the dynamic load ratio) can be 60% to 65%. For each converter station, as the dynamic load access ratio increases, the critical stable voltage parameter also increases. Therefore, to meet reactive power compensation requirements and ensure system transient voltage stability, a higher target total capacity is required. For a fixed capacity of a single phase-converter, more phase-converters need to be installed.

[0150] According to an embodiment of the present invention, the corresponding relationship between the installed capacity of the phase regulator and the dynamic load access ratio can be shown in Table 2 below.

[0151] Table 2

[0152]

[0153] The following takes the dynamic load ratio of 60% as an example to simulate the same converter station with different phase-shifting configuration combinations, and Figure 7a and Figure 7b The simulation results are explained.

[0154] Figure 7a The waveforms of reactive power compensation and reactive power demand changing over time for different phase-shifting configuration combinations according to an embodiment of the present invention are shown.

[0155] like Figure 7a As shown in the figure, the horizontal axis represents the time corresponding to different stages (unit: s), and the vertical axis represents the reactive power (unit: pu).

[0156] Figure 7b The waveforms showing the change of slip over time for different phase regulator configuration combinations according to an embodiment of the present invention are shown.

[0157] like Figure 7b As shown in the figure, the horizontal axis represents the time corresponding to different stages (unit: s), and the vertical axis represents the slip (unit: pu).

[0158] By comparison, it can be seen that when the phase regulator is not connected, the reactive power demand is not compensated due to the failure of DC continuous commutation, resulting in a continuous increase in the slip of the dynamic load and system instability. After installing one phase regulator, the phase regulator relies on strong excitation to achieve a reactive power compensation of nearly 2.3 times, but still fails to meet the reactive power demand caused by the reactive power consumption of the converter, causing the bus voltage parameter to be lower than the critical stable voltage parameter of the dynamic load, resulting in system instability. After installing two phase regulators, the target total capacity of the converter station is increased, and the reactive power compensation of 3.9 times the strong excitation meets the reactive power demand caused by the reactive power consumption of the converter. After the fault is cleared, the slip gradually decreases to 0, and the system returns to the state before the fault. The simulation results are consistent with the above calculations. Therefore, the optimal phase regulator configuration combination obtained by the method for determining the converter station parameters in the embodiment of the present invention has certain reliability and accuracy under different dynamic load ratios.

[0159] According to an embodiment of the present invention, by coupling the bus voltage parameters at different stages, the target configuration parameters are dynamically constrained according to the bus voltage stability constraints and reactive compensation constraints, and the transient voltage stability and economic cost of the optimal configuration combination of the phase-shifting phase are collaboratively considered, thereby providing certain technical support for the planning and operation of the hybrid power grid and promoting the development and progress of the power system in the direction of reactive compensation and transient stability.

[0160] Figure 8 A block diagram of a device for determining converter station parameters for improving transient voltage stability according to an embodiment of the present invention is shown.

[0161] like Figure 8 As shown, the determination device 800 includes an obtaining module 810 , a function construction module 820 , a constraint construction module 830 and a solving module 840 .

[0162] The obtaining module 810 is used to obtain the critical stable voltage parameter of the dynamic load associated with the converter station according to the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state and the rotor motion equation for transition from the rated working condition to the critical stable state working condition.

[0163] Function construction module 820 is used to construct a stability sub-objective function for characterizing the transient voltage stability of the target system based on the bus voltage parameters when the converter station is in different stages and the critical stability voltage parameters of the associated dynamic load, and to construct an economic cost sub-objective function for the target system based on the respective installation locations and capacities of different phase regulators in multiple converter stations in the target system, wherein the different stages include the sub-transient stage, the transient stage, and the post-fault removal recovery stage.

[0164] The constraint construction module 830 is used to construct reactive power compensation constraints and bus voltage stability constraints of the target system according to the critical stable voltage parameters.

[0165] The solution module 840 is used to solve the optimal configuration combination of the phase regulator based on the stability sub-objective function, the economic cost sub-objective function, the reactive power compensation constraint and the bus voltage stability constraint, and output the target configuration of each of the multiple converter stations in the target system.

[0166] According to an embodiment of the present invention, the function building module 820 includes a first building submodule and a second building submodule.

[0167] The first construction submodule is used to construct a stability sub-objective function based on the integration of the differences between the bus voltage parameters and the critical stability voltage parameters of the multiple converter stations in the sub-transient stage, the transient stage and the recovery stage after fault removal.

[0168] The second construction submodule is used to construct an economic cost sub-objective function based on the respective installation locations and capacities of different phase regulators in multiple converter stations.

[0169] According to an embodiment of the present invention, the obtaining module 810 includes a construction submodule and a simultaneous submodule.

[0170] The construction submodule is used to construct the torque balance equation based on the mechanical torque and electromagnetic torque corresponding to the critical stable state.

[0171] The simultaneous submodule is used to simultaneously solve the torque balance equation and the rotor motion equation to obtain the critical stable voltage parameters.

[0172] According to an embodiment of the present invention, the constraint construction module 830 includes an acquisition submodule, a obtainment submodule and a first constraint construction submodule.

[0173] The acquisition submodule is used to obtain rated parameters of the converter and the static VAR compensator respectively.

[0174] The obtaining submodule is used to obtain the rated reactive output of the static VAR compensator and the reactive consumption threshold of the converter according to the rated parameters.

[0175] The first constraint construction submodule is used to construct reactive power compensation constraints of the target system according to the rated reactive power output and reactive power consumption threshold.

[0176] According to an embodiment of the present invention, the constraint construction submodule includes a first construction unit, a second construction unit, an acquisition unit and a third construction unit.

[0177] The first constructing unit is configured to construct reactive power compensation constraints for each of the plurality of converter stations according to the rated reactive power output and the reactive power consumption threshold.

[0178] The second constructing unit is configured to construct reactive power compensation constraints of the target system according to reactive power compensation constraints of the plurality of converter stations.

[0179] According to an embodiment of the present invention, the constraint construction module 830 further includes a second constraint construction submodule, an acquisition submodule, and a third constraint construction submodule.

[0180] The second constraint construction submodule is used to construct a first bus voltage constraint according to the critical stable voltage parameter, so that the bus voltage parameters at different stages are all greater than the critical stable voltage parameter.

[0181] The acquisition submodule is used to obtain the rated voltage parameters of the converter station before the fault.

[0182] The third constraint construction submodule is used to construct a second bus voltage constraint based on the rated voltage parameters of the converter station before the fault and multiple predetermined constraint multiples corresponding to multiple target moments, wherein the target moment is any moment within different stages.

[0183] According to an embodiment of the present invention, the solution module 840 includes a construction submodule, a determination submodule, and an output submodule.

[0184] The submodule is constructed to construct the target configuration function of the target system according to the Euclidean distance between the stability sub-objective function and the phase-shifting economic cost sub-objective function.

[0185] The determination submodule is used to determine multiple candidate phase-converter configuration combinations based on the target configuration function, reactive power compensation constraints and bus voltage stability constraints.

[0186] The output submodule is used to solve the optimal configuration combination of the phase regulator according to multiple candidate phase regulator configuration combinations, and output the target configuration parameters of each of the multiple converter stations in the target system.

[0187] According to an embodiment of the present invention, the output submodule includes an obtaining unit and a determining unit.

[0188] The obtaining unit is used to obtain the target total capacity of the target system according to the reactive compensation constraint of the converter station, the bus voltage stability constraint and the proportional parameter of the dynamic load.

[0189] The determining unit is configured to determine a plurality of target phase condenser configuration combinations from a plurality of candidate phase condenser configuration combinations based on the target total capacity.

[0190] Any number of the modules, submodules, units, and subunits according to embodiments of the present invention, or at least part of the functionality of any number of these units, can be implemented in a single module. Any one or more of the modules, submodules, units, and subunits according to embodiments of the present invention can be split into multiple modules for implementation. Any one or more of the modules, submodules, units, and subunits according to embodiments of the present invention can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application-specific integrated circuit (ASIC), or can be implemented in hardware or firmware using any other reasonable method of circuit integration or packaging, or can be implemented in any one of the three implementation methods of software, hardware, and firmware, or any appropriate combination of any of these. Alternatively, one or more of the modules, submodules, units, and subunits according to embodiments of the present invention can be at least partially implemented as a computer program module that, when executed, can perform the corresponding functionality.

[0191] For example, any number of the obtaining module 810, the function construction module 820, the constraint construction module 830, and the solving module 840 can be combined into a single module / unit / sub-unit, or any one of these modules / units / sub-units can be split into multiple modules / units / sub-units. Alternatively, at least part of the functionality of one or more of these modules / units / sub-units can be combined with at least part of the functionality of other modules / units / sub-units and implemented in a single module / unit / sub-unit. According to an embodiment of the present invention, at least one of the obtaining module 810, the function construction module 820, the constraint construction module 830, and the solving module 840 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or can be implemented in hardware or firmware by any other reasonable means of circuit integration or packaging, or can be implemented in any one of the three implementation methods of software, hardware, and firmware, or any appropriate combination of any of these. Alternatively, at least one of the obtaining module 810 , the function building module 820 , the constraint building module 830 and the solving module 840 may be at least partially implemented as a computer program module, which may perform corresponding functions when executed.

[0192] It should be noted that the device part for determining the converter station parameters for improving transient voltage stability in the embodiment of the present invention corresponds to the method part for determining the converter station parameters for improving transient voltage stability in the embodiment of the present invention. The description of the device part specifically refers to the method part and will not be repeated here.

[0193] Figure 9 A block diagram of an electronic device suitable for implementing a method for determining converter station parameters for improving transient voltage stability according to an embodiment of the present invention is shown.

[0194] Figure 9 The electronic device shown is only an example and should not limit the functions and scope of use of the embodiments of the present invention.

[0195] like Figure 9As shown, an electronic device 900 according to an embodiment of the present invention includes a processor 901, which can perform various appropriate actions and processes based on programs stored in a read-only memory (ROM) 902 or programs loaded from a storage unit 908 into a random access memory (RAM) 903. The processor 901 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or related chipsets and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 901 may also include onboard memory for caching purposes. The processor 901 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present invention.

[0196] The RAM 903 stores various programs and data required for the operation of the electronic device 900. The processor 901, ROM 902, and RAM 903 are connected to each other via a bus 904. The processor 901 executes the programs in the ROM 902 and / or RAM 903 to perform various operations according to the method flow of the embodiment of the present invention. It should be noted that the programs may also be stored in one or more memories other than the ROM 902 and RAM 903. The processor 901 may also execute the programs stored in the one or more memories to perform various operations according to the method flow of the embodiment of the present invention.

[0197] According to an embodiment of the present invention, electronic device 900 may further include an input / output (I / O) interface 905, which is also connected to bus 904. Electronic device 900 may also include one or more of the following components connected to I / O interface 905: an input section 906 including a keyboard, mouse, etc.; an output section 907 including devices such as a cathode ray tube (CRT), liquid crystal display (LCD), and speakers; a storage section 908 including a hard disk; and a communication section 909 including a network interface card such as a LAN card or modem. Communication section 909 performs communication processing via a network such as the Internet. A drive 910 is also connected to I / O interface 905 as needed. Removable media 911, such as a magnetic disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed in drive 910 as needed, so that computer programs read from the removable media can be installed into storage section 908 as needed.

[0198] According to an embodiment of the present invention, the method flow according to an embodiment of the present invention can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product, which includes a computer program carried on a computer-readable storage medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 909, and / or installed from the removable medium 911. When the computer program is executed by the processor 901, the above-mentioned functions defined in the system of the embodiment of the present invention are executed. According to an embodiment of the present invention, the system, equipment, device, module, unit, etc. described above can be implemented by a computer program module.

[0199] The present invention also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments, or may exist independently and not incorporated into the device / apparatus / system. The computer-readable storage medium carries one or more programs, which, when executed, implement the method according to the embodiments of the present invention.

[0200] According to embodiments of the present invention, a computer-readable storage medium may be a non-volatile computer-readable storage medium. Examples include, but are not limited to, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0201] For example, according to an embodiment of the present invention, the computer-readable storage medium may include the ROM 902 and / or the RAM 903 described above and / or one or more memories other than the ROM 902 and the RAM 903 .

[0202] An embodiment of the present invention also includes a computer program product, which includes a computer program, which contains program code for executing the method provided by the embodiment of the present invention. When the computer program product is run on an electronic device, the program code is used to enable the electronic device to implement the block diagram of the electronic device of the method for determining converter station parameters for improving transient voltage stability provided by the embodiment of the present invention.

[0203] When the computer program is executed by the processor 901, the above functions defined in the system / device of the embodiment of the present invention are performed. According to the embodiment of the present invention, the above-described systems, devices, modules, units, etc. can be implemented by computer program modules.

[0204] In one embodiment, the computer program may be stored on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may be transmitted and distributed in the form of a signal on a network medium, downloaded and installed via the communication portion 909, and / or installed from a removable medium 911. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to wireless, wired, or any suitable combination thereof.

[0205] According to an embodiment of the present invention, the program code for executing the computer program provided by the embodiment of the present invention can be written in any combination of one or more programming languages. Specifically, these computer programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, Python, "C" or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (for example, using an Internet service provider to connect via the Internet).

[0206] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of the systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each box in the flowchart or block diagram may represent a module, program segment, or portion of code, which contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the boxes may occur in an order different from that marked in the accompanying drawings. For example, two boxes shown in succession may actually be executed substantially in parallel, or they may sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, as well as the combination of boxes in the block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or may be implemented using a combination of dedicated hardware and computer instructions. It will be understood by those skilled in the art that the features described in the various embodiments of the present invention may be combined and / or coupled in various ways, even if such combinations or couplings are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention may be combined and / or coupled in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or combinations fall within the scope of the present invention.

[0207] The above describes embodiments of the present invention. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be advantageously used in combination. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A method for determining converter station parameters for improving transient voltage stability, characterized in that: The converter station includes a phase regulator, and the method includes: Obtaining a critical stable voltage parameter of the dynamic load associated with the converter station based on the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state and a rotor motion equation for transition from a rated operating condition to a critical stable state operating condition; A stability sub-objective function for characterizing the transient voltage stability of the target system is constructed based on bus voltage parameters and critical stability voltage parameters of associated dynamic loads when the converter station is in different stages, and an economic cost sub-objective function of the target system is constructed based on the respective installation locations and capacities of different phase regulators in the plurality of converter stations in the target system, wherein the different stages include a sub-transient stage, a transient stage, and a post-fault clearing recovery stage; constructing reactive power compensation constraints and bus voltage stability constraints of the target system according to the critical stable voltage parameters; Based on the stability sub-objective function, the economic cost sub-objective function, the reactive power compensation constraint and the bus voltage stability constraint, the optimal configuration combination of the phase regulator is solved, and the target configuration parameters of each of the multiple converter stations in the target system are output.

2. The method according to claim 1, characterized in that The method comprises: constructing a stability sub-objective function for characterizing the transient voltage stability of the target system according to the bus voltage parameters of the converter station at different stages and the critical stability voltage parameters of the associated dynamic loads; and constructing an economic cost sub-objective function of the target system according to the respective installation locations and capacities of the multiple converter stations in the target system of different phase regulators, including: constructing the stability sub-objective function according to the integral of the difference between the bus voltage parameter and the critical stability voltage parameter of each of the plurality of converter stations in the sub-transient stage, the transient stage, and the post-fault removal recovery stage; The economic cost sub-objective function is constructed based on the respective installation locations and capacities of the different phase regulators in the plurality of converter stations.

3. The method according to claim 1, characterized in that The method of obtaining the critical stable voltage parameter of the dynamic load associated with the converter station based on the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state and the rotor motion equation for transition from the rated operating condition to the critical stable state operating condition includes: constructing a torque balance equation based on the mechanical torque and electromagnetic torque corresponding to the critical stable state; The torque balance equation and the rotor motion equation are combined to obtain the critical stable voltage parameter.

4. The method according to claim 3, characterized in that The converter station further includes a converter and a static VAR compensator. The step of constructing the reactive compensation constraint and bus voltage stability constraint of the target system according to the critical stable voltage parameter includes: respectively obtaining rated parameters of the converter and the static VAR compensator; According to the rated parameters, respectively obtaining the rated reactive output of the static VAR compensator and the reactive consumption threshold of the converter; A reactive compensation constraint of the target system is constructed according to the rated reactive output and the reactive consumption threshold.

5. The method according to claim 4, characterized in that The constructing the reactive compensation constraint of the target system according to the rated reactive output and the reactive consumption threshold includes: constructing reactive power compensation constraints for each of the plurality of converter stations according to the rated reactive power output and the reactive power consumption threshold; The reactive power compensation constraints of the target system are constructed according to the reactive power compensation constraints of the plurality of converter stations.

6. The method according to claim 5, characterized in that The bus voltage stability constraint includes a first bus voltage constraint and a second bus voltage constraint. Constructing the reactive power compensation constraint and the bus voltage stability constraint of the target system according to the critical stable voltage parameter includes: constructing the first bus voltage constraint according to the critical stable voltage parameter, so that the bus voltage parameters at the different stages are all greater than the critical stable voltage parameter; Obtaining the rated voltage parameters of the converter station before the fault; The second bus voltage constraint is constructed according to the rated voltage parameter of the converter station before the fault and a plurality of predetermined constraint multiples corresponding to a plurality of target moments, wherein the target moment is any moment within the different stages.

7. The method according to claim 5, characterized in that Solving the optimal configuration combination of the phase regulator based on the stability sub-objective function, the economic cost sub-objective function, the reactive power compensation constraint, and the bus voltage stability constraint, and outputting target configuration parameters of the plurality of converter stations in the target system, includes: constructing a target configuration function of the target system according to the Euclidean distance between the stability sub-objective function and the economic cost sub-objective function; Determining a plurality of candidate phase-converter configuration combinations according to the target configuration function, the reactive power compensation constraint, and the bus voltage stability constraint; The optimal phase modulator configuration combination is solved based on the multiple candidate phase modulator configuration combinations, and the target configuration parameters of each of the multiple converter stations in the target system are output.

8. The method according to claim 7, characterized in that Solving the optimal phase regulator configuration combination according to the multiple candidate phase regulator configuration combinations and outputting the target configuration parameters of each of the multiple converter stations in the target system includes: Obtaining a target total capacity of the target system according to the converter station reactive compensation constraint, the bus voltage stability constraint, and a proportional parameter of the dynamic load; Based on the target total capacity, determining a plurality of target phase condenser configuration combinations from the plurality of candidate phase condenser configuration combinations; The target configuration function is solved, the optimal phase modulator configuration combination is determined from the multiple target phase modulator configuration combinations, and the target configuration parameters of each of the multiple converter stations in the target system are output.

9. The method according to claim 8, characterized in that Solving the target configuration function to determine the optimal phase condenser configuration combination from the multiple target phase condenser configuration combinations includes: Sorting the target configuration function values ​​corresponding to the plurality of target phase condenser configuration combinations to obtain a sorting result; Based on the ranking results, the optimal configuration combination of the phase modulators is determined.

10. A device for determining converter station parameters for improving transient voltage stability, characterized in that: include: an obtaining module, configured to obtain a critical stable voltage parameter of the dynamic load associated with the converter station based on the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state and a rotor motion equation for transition from a rated operating condition to a critical stable state operating condition; a function construction module, configured to construct a stability sub-objective function for characterizing the transient voltage stability of the target system based on bus voltage parameters and critical stability voltage parameters of associated dynamic loads when the converter station is in different stages, and to construct an economic cost sub-objective function for the target system based on the respective installation locations and capacities of different phase regulators in the plurality of converter stations in the target system, wherein the different stages include a sub-transient stage, a transient stage, and a post-fault clearing recovery stage; A constraint construction module, configured to construct reactive power compensation constraints and bus voltage stability constraints of the target system according to the critical stable voltage parameters; A solution module is used to solve the optimal configuration combination of the phase regulator based on the stability sub-objective function, the economic cost sub-objective function, the reactive power compensation constraint and the bus voltage stability constraint, and output the target configuration of each of the multiple converter stations in the target system.

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