Method and device for determining converter station parameters for improving transient voltage stability

Abstract

The application provides a determination method and device for converter station parameters for improving transient voltage stability, which can be applied to the technical field of automatic configuration of hybrid power grids. The method comprises the following steps: obtaining critical stability voltage parameters of dynamic loads associated with the converter station according to the mechanical torque and electromagnetic torque of dynamic charges corresponding to the critical stability state and the rotor motion equation; constructing a stability sub-objective function for characterizing the transient voltage stability of the target system according to the bus voltage parameters and the critical stability voltage parameters of the associated dynamic loads when the converter station is in different stages, and constructing an economic cost sub-objective function of the target system according to the installation positions and capacities of different phase-modulating machines in the multiple converter stations in the target system; constructing the reactive power compensation constraint and the bus voltage stability constraint of the target system according to the critical stability voltage parameters; solving the optimal configuration combination of the phase-modulating machine and outputting the target configuration parameters of the multiple converter stations.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automatic configuration of hybrid power grids, and more particularly to a method and device for determining parameters of converter stations for improving transient voltage stability. BACKGROUND

[0002] With the rapid development of ultra-high voltage direct current transmission systems, the receiving end power grid presents a multi-infeed direct current hybrid characteristic. Therefore, the receiving end power grid simultaneously carries a large amount of reactive power (hereinafter referred to as reactive power) load and new energy, and faces the risk of low inertia operation and commutation failure, thereby causing the system to be prone to transient voltage instability when disturbed.

[0003] In the process of implementing the present application concept, it is found through research that the reactive power supplement method in the related art cannot meet the large-scale transient support demand, resulting in low transient voltage stability of the system. SUMMARY

[0004] Therefore, the present application provides a method and device for determining parameters of converter stations for improving transient voltage stability.

[0005] One aspect of the present application provides a method for determining parameters of converter stations for improving transient voltage stability, the converter station comprising a phase modifier, the method comprising:

[0006] According to the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state, and the rotor motion equation from the rated operating condition to the critical stable state operating condition, the critical stable voltage parameter of the dynamic load associated with the converter station is obtained; according to the bus voltage parameter and the critical stable voltage parameter of the associated dynamic load when the converter station is in different stages, a stability sub-objective function for characterizing the transient voltage stability of the target system is constructed, and an economic cost sub-objective function of the target system is constructed according to the respective installation positions and capacities of different phase modifiers in the plurality of 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; according to the critical stable voltage parameter, the reactive power compensation constraint and the bus voltage stability constraint of the target system are constructed; 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 modifier is solved, and the target configuration parameters of the plurality of converter stations in the target system are output.

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

[0008] The module obtains the critical stable 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 stable state, as well as the rotor motion equations for the transition from rated operating conditions to critical stable state operating conditions.

[0009] The function construction module is used to construct a stability sub-objective function to characterize the transient voltage stability of the target system based on the bus voltage parameters and the critical stable voltage parameters of the associated dynamic loads when the converter station is in different stages. It also constructs an economic cost sub-objective function of the target system based on the installation location and capacity of different synchronous condensers in multiple converter stations in the target system. The different stages include the subtransient stage, the transient stage, and the recovery stage after fault clearing.

[0010] The constraint construction module is used to construct reactive power compensation constraints and bus voltage stability constraints for the target system based on the critical stability voltage parameters.

[0011] The solution module is used to solve for the optimal configuration combination of synchronous condensers 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 outputs the target configuration of each of the 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] Memory, used to store 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 described above.

[0016] According to the bus voltage parameters and the critical stability voltage parameters of the converter station in the sub-transient stage, the transient stage and the post-fault recovery stage, the stability sub-objective function is constructed, and the economic cost sub-objective function of the phase modifier is constructed, and the target configuration parameters are determined according to the critical stability voltage parameters of the dynamic load, the reactive power compensation constraint of the target system and the bus voltage stability constraint, compared with the traditional reactive power support mode which only considers the single case of commutation failure, the different time scales corresponding to the three stages of the transient process are coupled, and the bus voltage changes in each stage of the transient process are fully considered. At the same time, the optimal configuration model of the phase modifier is solved by combining the critical stability voltage parameters of the dynamic load, the reactive power compensation constraint of the target system, the bus voltage stability constraint and the economic cost sub-objective function of the phase modifier, so that the target configuration parameters obtained realize the reactive power compensation which meets the reactive power demand while having certain reliability and economy. Therefore, the phase modifier configuration of the converter station according to the target configuration parameters is beneficial to realizing the maximum utilization efficiency of the phase modifier while improving the transient voltage stability of the system. BRIEF DESCRIPTION OF DRAWINGS

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

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

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

[0020] Figure 3 A topology structure diagram of the power grid is shown. Figure 1 A topology structure diagram of the power grid is shown.

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

[0022] Figure 5a A bus voltage waveform 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 application is shown.

[0023] Figure 5b A bus voltage waveform 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 application is shown.

[0024] Figure 5c A bus voltage waveform 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 application is shown.

[0025] Figure 5d Fig. 8 shows the bus voltage variation over time of the DF converter station after a three-phase short-circuit fault at the fault point B according to an embodiment of the present application.

[0026] Figure 6a Fig. 9 shows the target system node voltage variation over time under the rated power conversion operation mode according to an embodiment of the present application.

[0027] Figure 6b Fig. 10 shows the target system node voltage variation over time under the DC filter switching operation mode according to an embodiment of the present application.

[0028] Figure 6c Fig. 11 shows the target system node voltage variation over time under the commutation failure operation mode according to an embodiment of the present application.

[0029] Figure 6d Fig. 12 shows the target system node voltage variation over time under the short-circuit fault operation mode according to an embodiment of the present application.

[0030] Figure 7a Fig. 13 shows the reactive power compensation and demand variation over time of different phase modifier configuration combinations according to an embodiment of the present application.

[0031] Figure 7b Fig. 14 shows the slip variation over time of different phase modifier configuration combinations according to an embodiment of the present application.

[0032] Figure 8 Fig. 15 shows a block diagram of a determination device for converter station parameters for improving transient voltage stability according to an embodiment of the present application.

[0033] Figure 9 Fig. 16 shows a block diagram of an electronic device suitable for implementing a determination method for converter station parameters for improving transient voltage stability according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. It is to be understood, however, that the description is merely exemplary and is not intended to limit the scope of the present application. In the following detailed description of the embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the present application. However, it would be apparent to those skilled in the art that the embodiments of the present application can be practiced without these specific details. In other instances, well-known structures and functions have not been described in detail in order to avoid obscuring the concepts of the present application.

[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the terms "comprises", "comprising", "includes", "including" and the like are specifically intended to be open-ended terms meaning that other elements can be added.

[0036] All terms used herein including technical and scientific terms have the meanings commonly understood by one of ordinary skill in the art unless otherwise specified. It should be noted that the use of any terms herein should not be interpreted to limit the scope of the present disclosure to only those embodiments described herein. Rather, the terms should be interpreted broadly to include any embodiment that falls within the scope of the present disclosure.

[0037] In the case of using expressions similar to "at least one of A, B, and C, etc.", it is generally intended to include any of the A, B, and C, etc. individually and also to include two or more of A, B, and C, etc. in combination. For example, "a system having at least one of A, B, and C" is intended to include a system having A alone, a system having B alone, a system having C alone, a system having A and B together, a system having A and C together, a system having B and C together, and also a system having A, B, and C together, etc.

[0038] In the process of implementing the inventive concept of the present application, it is found through research that, as an important device in an AC-DC hybrid power grid, a converter needs to consume a large amount of reactive power in the process of commutation, and therefore, some reactive power compensation devices, such as a static var compensator (SVC), are usually equipped in a converter station. In a normal operation state of a multi-infeed DC system, the reactive power compensation provided by the reactive power compensation devices is approximately equal to the reactive power consumption of the converter, but in a fault condition, whether the commutation fails or succeeds, a large amount of reactive power needs to be absorbed in the process of the system transition from a transient state to a steady state, and the reactive power will continue to be absorbed for a long period of time after the fault is removed.

[0039] However, the reactive power compensation provided by the reactive power compensation devices in the related art converter station is proportional to the square of the bus voltage, and therefore, in the case of an AC fault, the decrease of the bus voltage will cause the reactive power compensation output by the reactive power compensation devices, such as the SVC, to also decrease substantially, and the reactive power compensation required by the system in the transient process is higher than that in the normal operation, and therefore, it is difficult to meet the transient reactive power demand of the system by relying only on the existing reactive power compensation devices, and thus it is difficult for the system to quickly restore the transient stable voltage after the fault condition.

[0040] Therefore, embodiments of the present application provide a determination method of converter station parameters for improving transient voltage stability, comprising: obtaining a critical stability voltage parameter of a dynamic load associated with a converter station according to a mechanical torque and an electromagnetic torque of the dynamic load corresponding to a critical stability state, and a rotor motion equation from a rated operating condition to the critical stability state operating condition; constructing a stability sub-objective function for characterizing transient voltage stability of a target system according to bus voltage parameters of the converter station at different stages and the critical stability voltage parameter of the associated dynamic load, and constructing an economic cost sub-objective function of the target system according to respective installation positions and capacities of different phase-modulating machines in multiple converter stations in the target system, wherein the different stages include a sub-transient stage, a transient stage, and a post-fault removal recovery stage; constructing a reactive power compensation constraint and a bus voltage stability constraint of the target system according to the critical stability voltage parameter; and solving an optimal configuration combination of the phase-modulating machine 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 respective target configuration parameters of the multiple converter stations in the target system.

[0041] According to embodiments of the present application, the converter station comprises a phase-modulating machine and a converter, and the phase-modulating machine is configured to provide reactive power compensation for the system on the basis of a conventional reactive power compensation device. In order to better understand the application scenarios to which the determination method of embodiments of the present application is applicable, the overall architecture of a multi-infeed DC system will be described below. Figure 1

[0042] Figure 1 A structure diagram of a multi-infeed DC system receiving-end power grid according to embodiments of the present application is shown.

[0043] As shown in Figure 1 , the multi-infeed DC system receiving-end power grid comprises multiple substations (MM substation, CH substation, ZJ substation, PC substation, and SZ substation) and multiple UHV converter stations (CX converter station, LM converter station, BA converter station, and DF converter station) connected through AC lines. UHV DC lines (NC DC line, LL DC line, JZ DC line, and XD DC line) are respectively connected to the multiple UHV converter stations for DC power transmission, and the multiple UHV converter stations convert DC voltage into AC voltage and transmit the AC voltage to the multiple substations through the AC lines for power distribution, so as to supply multiple power consumption devices including dynamic loads such as induction motors, and the reactive power demand or active power demand of the dynamic loads and other power consumption devices will change the bus voltage of the converter station, thereby affecting the transient voltage stability of the converter station.

[0044] Figure 2 A flowchart of a determination method of converter station parameters for improving transient voltage stability according to embodiments of the present application is shown.

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

[0046] At operation S210, a critical stability voltage parameter of a dynamic load associated with a converter station is obtained according to a mechanical torque and an electromagnetic torque of the dynamic load corresponding to a critical stability state, and a rotor motion equation of a transition from a rated operating condition to the critical stability state operating condition.

[0047] According to an embodiment of the present application, the critical stability voltage parameter of the dynamic load characterizes a minimum voltage threshold for maintaining stable operation of the dynamic load. The bus voltage parameter of the converter station at any time after a fault is greater than the critical stability voltage parameter of the dynamic load, that is, the critical stability voltage parameter of the dynamic load is the minimum threshold of the bus voltage parameter.

[0048] According to an embodiment of the present application, taking a dynamic load as an induction motor for example, a mechanical torque drives the rotor to rotate, promotes the relative motion of the magnetic field, and causes the electromagnetic induction to generate a potential difference. An electromagnetic torque promotes the rotor to continue to rotate through the relative motion of the magnetic field, and the two together maintain the stable operation of the induction motor and ensure the continuous output of electric energy.

[0049] According to an embodiment of the present application, under the critical stability state, the electromagnetic torque and the mechanical torque are balanced, that is, the electromagnetic power and the mechanical power are equal.

[0050] At operation S220, a stability sub-objective function for characterizing transient voltage stability of a target system is constructed according to bus voltage parameters and the critical stability voltage parameters of the dynamic load associated with the converter station at different stages, and an economic cost sub-objective function of the target system is constructed according to installation positions and capacities of different phase-modulating machines in multiple converter stations in the target system.

[0051] According to an embodiment of the present application, different stages include a sub-transient stage, a transient stage, and a post-fault recovery stage in sequence. The sub-transient stage of the phase-modulating machine is mainly to damp the winding, and after the dynamic attenuation of the damping winding, the phase-modulating machine enters the transient stage mainly to the field winding and the field regulator. The process of breaking through the limitation of the transient time constant through strong excitation after the fault is removed, continuously and efficiently providing reactive power support, is the post-fault recovery stage, which accelerates voltage recovery.

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

[0053] According to an embodiment of the present application, according to the UHV AC / DC hybrid power grid topology of the receiving end of the multi-infeed DC system, the converter station data, the candidate type parameters and economic parameters of the phase modifier, the dynamic load access ratio and its parameters, and other data and parameters related to economic planning, the following formula (1) is constructed .

[0054] (1);

[0055] wherein the economic cost sub-target function of the phase modifier represents the function relationship between the economic cost of the plurality of converter stations and the total capacity of the phase modifier in each converter station, and therefore the function value of is taken as the target for configuring the phase modifier. n is the total number of converter stations in the target system, represents the initial cost of the i th converter station, and the initial cost includes the land acquisition cost, the transportation, construction and installation cost, and the equipment purchase cost. The purchase cost and the operation and maintenance cost of the same equipment are roughly the same, but the land acquisition cost and the transportation cost are slightly different in different places, and the cost will have slight differences. represents the operation and maintenance cost of the unit capacity phase modifier in the whole life cycle, represents the total capacity of the phase modifier installed in the i th converter station. The purchase cost and the operation and maintenance cost of the same equipment are roughly the same, but the land acquisition cost and the transportation cost are slightly different in different places, and the cost will have slight differences.

[0056] According to an embodiment of the present application, the single converter station includes a plurality of installation points of the phase modifier, for example, the CX converter station includes 4 installation points. For the phase modifier with fixed capacity, the number of installations is different, the function value is different.

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

[0058] According to an embodiment of the present application, the reactive power compensation constraint represents the minimum reactive power compensation required by the converter station, which is used as a constraint condition in subsequent determination of the target configuration parameter, to ensure that the target configuration parameter obtained can meet the economic demand and can have the reactive power compensation required by the converter station after the fault.

[0059] According to an embodiment of the present application, the bus voltage stability constraint can be constructed according to the specification adopted in the actual demand.

[0060] In operation S240, the optimal configuration combination of the phase modifier is solved 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 target configuration parameters of the multiple converter stations in the target system are output.

[0061] According to an embodiment of the present application, the optimal configuration model of the phase modifier can be constructed with the highest function value of the stability sub-objective function and the lowest function value of the economic cost sub-objective function of the target system as the target, and the optimal configuration combination of the phase modifier can be solved based on the reactive power compensation constraint and the bus voltage stability constraint by using the particle swarm optimization algorithm to output the target configuration parameters of the converter station.

[0062] According to an embodiment of the present application, the stability sub-objective function is constructed according to the bus voltage parameters and the critical stability voltage parameters of the dynamic load of the converter station in the sub-transient stage, the transient stage and the post-fault recovery stage, and the economic cost sub-objective function of the phase modifier is constructed, and the target configuration parameters are determined according to the critical stability voltage parameters of the dynamic load, the reactive power compensation constraint and the bus voltage stability constraint of the target system. Compared with the traditional reactive power support mode which only considers the single case of commutation failure, the different time scales corresponding to the three stages of the transient process are coupled, and the bus voltage changes in each stage of the transient process are fully considered. At the same time, the optimal configuration model of the phase modifier is solved in combination with the critical stability voltage parameters of the dynamic load, the reactive power compensation constraint and the bus voltage stability constraint of the target system and the economic cost sub-objective function of the phase modifier, so as to ensure that the reactive power compensation realized by the target configuration parameters has certain reliability and economy while meeting the reactive power demand. Therefore, the configuration of the phase modifier of the converter station according to the target configuration parameters is conducive to realizing the maximum utilization efficiency of the phase modifier while improving the transient voltage stability of the system.

[0063] According to an embodiment of the present application, the stability sub-objective function for representing the transient voltage stability of the target system is constructed according to the bus voltage parameters of the converter station in different stages and the critical stability voltage parameters of the associated dynamic load, and the economic cost sub-objective function of the target system is constructed according to the installation positions and capacities of different phase modifiers in the multiple converter stations, including: constructing the stability sub-objective function according to the integrals 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 post-fault recovery stage, respectively; and constructing the economic cost sub-objective function based on the installation positions and capacities of different phase modifiers in the multiple converter stations.

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

[0065] (2)

[0066] in, This represents the transient voltage stability margin of the i-th converter station. Let represent the bus voltage parameter of the i-th converter station at time t. Let t0 represent the critical stable voltage parameter of the bus of the i-th converter station, t1 represent the start time of the subtransient stage, t2 represent the end time of the subtransient stage and the start time of the transient stage, t3 represent the end time of the transient stage and the start time of the recovery stage after fault clearing, and t3 represent the end time of the recovery stage after fault clearing.

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

[0068] Figure 3 It shows Figure 1 The diagram shows the topology of the power grid.

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

[0070] The converter 310, connected to the input power supply, consumes a large amount of reactive power during faults, making it prone to commutation failure and causing a sharp drop in bus voltage. The reactive power compensation provided by the SVC320 is proportional to the square of the bus voltage; therefore, the reactive power compensation provided during faults is insufficient to meet the demand. Thus, reactive power compensation can be provided by appropriately configuring the capacity and number of synchronous condensers 330 to support transient voltage. During a fault, the 500kV bus voltage drop will be conducted to the 10kV bus through the transformer 350 and equivalent impedance 340. The dynamic load 360 is sensitive to voltage fluctuations, and its motors are 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, the critical stable voltage parameters of the dynamic load associated with the converter station are obtained based on the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state, and the rotor motion equations for the transition from rated operating condition to critical stable state operating condition. This includes: constructing a torque balance equation based on the mechanical torque and electromagnetic torque corresponding to the critical stable state; and simultaneously solving the torque balance equation and the rotor motion equations to obtain the critical stable voltage parameters of the dynamic load associated with the converter station.

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

[0073] (3) ;

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

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

[0076] (4) ;

[0077] wherein P e represents the mechanical power, S M represents the dynamic load capacity, S ac represents the short-circuit capacity of the alternating current system, X w represents the stator reactance of the dynamic load, X r represents the rotor reactance of the dynamic load, and R r represents the rotor resistance of the dynamic load.

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

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

[0080] (5) ;

[0081] wherein T r represents the rotor inertia time constant, t cr represents the time of fault removal, s1 represents the slip of the rated operating condition, and s3 represents the slip of the critical stable state operating condition.

[0082] According to an embodiment of the present application, the converter station further comprises a static reactive compensator and a converter. According to the critical stable voltage parameter, the reactive power compensation constraint and the bus voltage stability constraint of the target system are constructed, comprising: acquiring the rated parameters of the converter and the static reactive compensator respectively; according to the rated parameters, obtaining the rated reactive power output of the static reactive compensator and the reactive power consumption threshold of the converter respectively; and according to the rated reactive power output and the reactive power consumption threshold, constructing the reactive power compensation constraint of the target system.

[0083] According to an embodiment of the present application, the reactive power compensation constraint of the target system is constructed according to the rated reactive power output and the reactive power consumption threshold value, which comprises: constructing the reactive power compensation constraint of each of the plurality of converter stations according to the rated reactive power output and the reactive power consumption threshold value; and constructing the reactive power compensation constraint of the target system according to the reactive power compensation constraint of each of the plurality of converter stations.

[0084] According to an embodiment of the present application, the phase modifier is free of active load, the power angle δ≈0, and the phase modifier is mostly of a hidden pole structure, so the active power P SC and the reactive power Q SC may be respectively represented by the following formulas (6) and (7).

[0085] (6) ;

[0086] (7) ;

[0087] wherein 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 represents the d-axis reactance, U bus represents the equivalent bus voltage, and the q-axis voltage drop value of the phase modifier after a system fault without considering the excitation regulation is , u q0 represents the pre-fault q-axis voltage, the d-axis voltage drop value is , and u d0 represents the pre-fault d-axis voltage. Therefore, the d-axis flux linkage and the q-axis flux linkage may be respectively represented by the following formulas (8) and (9).

[0088] (8) ;

[0089] (9) ;

[0090] wherein r represents the stator resistance, and p is a complex variable of Laplace transform. By combining formula (8) and formula (6), the time-domain expression of may be obtained by performing Laplace inverse transform on the d-axis current variation and superimposing the steady-state component, as shown in the following formula (10).

[0091] (10) ;

[0092] wherein may represent the d-axis sub-transient reactance, may represent the d-axis sub-transient short-circuit time constant; represents the d-axis transient reactance, represents the d-axis sub-transient short-circuit time constant, T a represents the stator non-periodic component time constant, represents the bus voltage drop value.

[0093] According to an embodiment of the present application, the reactive power compensation of the phase modifier in the sub-transient stage may be represented as the following formula (11).

[0094] (11);

[0095] wherein, U s0 represents the voltage before the disturbance, U s1 represents the voltage after the disturbance. It can be seen that the output of the phase modifier in the sub-transient stage includes an alternating current component decaying with as a constant, a steady-state component, a sub-transient component caused by the damping winding decaying with as a constant, and a transient component caused by the excitation winding decaying with as a constant. Therefore, the reactive power compensation of the phase modifier in the sub-transient stage is proportional to the bus voltage drop value, which is different from the reactive power compensation of the SVC being proportional to the square of the bus voltage. Therefore, the greater the bus voltage drop value, the more reactive power compensation provided by the phase modifier in the sub-transient stage, which can effectively avoid the DC commutation failure.

[0096] According to an embodiment of the present application, the q-axis transient potential of the phase modifier in the transient stage may be represented as the following formula (12).

[0097] (12).

[0098] According to an embodiment of the present application, the relationship between the imaginary no-load potential change amount and may be represented as the following formula (13).

[0099] (13).

[0100] According to an embodiment of the present application, the reactive power compensation of the phase modifier in the transient stage may be represented as the following formula (14).

[0101] (14);

[0102] wherein, The strong field multiple of the excitation system is known, and thus the strong field control of the excitation system can increase the reactive power compensation of the phase modifier. The strong field of the excitation system reaches the maximum multiple in about 0.06 s. Therefore, the period from the fault occurrence to 0.06 s corresponds to the sub-transient stage. Subsequently, the system enters the transient stage mainly controlled by the excitation control. Under the action of the strong field, the reactive power compensation can continuously provide support for the bus voltage.

[0103] Based on this, the reactive power compensation of the SVC and the reactive power compensation of the phase modifier of the i-th converter station in the sub-transient stage need to exceed the threshold of the reactive power consumption 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] wherein, represents the reactive power exchange of the i-th converter station, represents the rated reactive power output of the SVC installed in the i-th converter station, m i represents the number of phase modifiers installed in the i-th converter station, n i represents the number of converters installed in the i-th converter station.

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

[0107] (16).

[0108] According to the embodiment of the present application, the reactive power compensation constraint and the bus voltage stability constraint of the target system are constructed according to the critical stability voltage parameter, including: constructing the first bus voltage constraint according to the critical stability voltage parameter, so that the bus voltage parameter in different stages is greater than the critical stability voltage parameter; obtaining the rated voltage parameter of the converter station before the fault; and constructing the second bus voltage constraint according to the rated voltage parameter of the converter station before the fault and the plurality of predetermined constraint multiples corresponding to the plurality of target time points, wherein the target time point is any time point in different stages.

[0109] According to the embodiment of the present application, the bus voltage stability constraint includes the first bus voltage constraint and the second bus voltage constraint. In order to prevent the system voltage from collapsing due to insufficient dynamic electromagnetic torque and large amount of stall when the UHV AC / DC hybrid system fails, it is necessary to ensure that the bus voltage parameter of each converter station in different stages after the fault is greater than the critical stability voltage parameter, and thus the first bus voltage constraint can be constructed.

[0110] According to the embodiment of the present application, the predetermined constraint multiple can be set according to the requirements in the technical specification followed in actual application.

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

[0112] (17) ;

[0113] Wherein, the plurality of target time moments are t0+1, t0+10 and t0+60 respectively, and the predetermined constraint multiples corresponding to the plurality of target time moments are 0.75, 0.8 and 0.9 respectively. t0 represents the fault occurrence time moment, represents the bus voltage of the i th converter station before the fault, represents the second bus voltage constraint corresponding to the target time moment (t0+1), represents the second bus voltage constraint corresponding to the target time moment (t0+10), represents the second bus voltage constraint corresponding to the target time moment (t0+60).

[0114] Therefore, for the i th converter station, the bus voltage parameter at the t0+1 time moment needs to be greater than 0.75 times of the bus voltage parameter at the t0+10 time moment needs to be greater than 0.8 times of the bus voltage parameter at the t0+60 time moment needs to be greater than 0.9 times of .

[0115] According to the embodiment of the present application, the rated parameters of the converter and the static var compensator are integrated, and the reactive power compensation constraint is constructed, which is beneficial to improve the accuracy of transient reactive power balance. The bus voltage stability constraint and the reactive power compensation constraint both adopt the hierarchical construction mode of constructing the constraint condition of a single converter station first and then summarizing the constraint of the system level, which avoids the cascading failure caused by local insufficient reactive power compensation and lays a certain foundation for the transient voltage stability of the ultra-high voltage power grid.

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

[0117] According to an embodiment of the present application, by using the Euclidean distance of the two sub-objective functions, the target sub-objective functions can be normalized into a single target configuration function, so that the subsequent solving can realize the optimization of the two sub-objective functions at the same time. The target configuration function F can be expressed as formula (18) as follows.

[0118] (18) ;

[0119] Wherein, M represents all candidate STATCOM configuration combinations, x represents any candidate STATCOM combination in M, represents the solution set in M that can realize the minimum function value of the economic cost sub-objective function in formula (1) above, represents the solution set in M that can realize the maximum function value of the stability sub-objective function in formula (2) above.

[0120] According to an embodiment of the present application, based on the rated parameters and the like obtained above, the target system can be simulated to obtain a simulation model, and the particle swarm optimization algorithm is used to solve the target configuration function to obtain the optimal STATCOM configuration combination.

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

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

[0123] As Figure 4 shown, the horizontal coordinate represents the transient voltage stability margin, with the unit of p.u.·s (per unit second), and the vertical coordinate represents the economic cost corresponding to the economic cost sub-objective function (with the unit of 100 million yuan). It can be seen that at least 4 STATCOMs are required to meet the transient stability requirement of the AC-DC hybrid power grid of the target system. With the increase of the STATCOM capacity, the economic cost also increases linearly, but the increase amplitude of the transient voltage stability margin gradually slows down. Therefore, it is not reasonable to blindly pay a large redundant economic cost in order to improve the transient voltage stability margin.

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

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

[0126] Table 1

[0127]

[0128] The installation positions of the phase modifier represent the positions of the predetermined number of phase modifier installations, which are DF converter station, CX converter station, BA converter station and LM converter station. Therefore, the target total capacity can be determined as 1500 MVar.

[0129] Based on the above table 1, it can be known that the DF converter station requires the largest number of phase modifiers because the AC power grid in the area where the DF converter station is located is weak in strength and a large number of dynamic loads are connected, resulting in poor transient voltage stability. In addition, the distance between the DF converter station and the BA converter station is close, and the interaction factor is large, so the transient voltage fluctuation of the DF converter station has a great influence on the BA converter station. Therefore, after the phase modifier installed in the DF converter station reaches the upper limit, the BA converter station should be considered first.

[0130] Therefore, combination 2, combination 3 and combination 4 are the target phase modifier configuration combinations selected according to the target total capacity.

[0131] According to the embodiments of the present application, the target configuration function is solved, and the optimal phase modifier configuration combination is determined from the plurality of target phase modifier configuration combinations, which comprises: sorting the target configuration function values corresponding to the plurality of target phase modifier configuration combinations respectively to obtain a sorting result; and determining the optimal phase modifier configuration combination based on the sorting result.

[0132] According to the embodiments of the present application, the target configuration function values corresponding to combination 2, combination 3 and combination 4 in the above table 1 are 0.355, 0.358 and 0.361 respectively, and according to the sorting result, it can be determined that combination 2 is the optimal phase modifier configuration combination.

[0133] In order to verify the accuracy of the determination method of the converter station parameters of the present application, the following will be verified by Figure 5a to 5d The optimal phase modifier configuration combination obtained above is verified, and the first control combination-combination 3 and the second control combination-combination 6 are added.

[0134] Figure 5a The bus voltage waveform of the BA converter station over time after the three-phase short-circuit fault at the fault point A according to the embodiments of the present application is shown.

[0135] Figure 5b The bus voltage waveform of the DF converter station over time after the three-phase short-circuit fault at the fault point A according to the embodiments of the present application is shown.

[0136] Figure 5c Fig. 4 shows the bus voltage variation waveform of the BA converter station after the three-phase short-circuit fault at the fault point B according to an embodiment of the present application.

[0137] Figure 5d Fig. 5 shows the bus voltage variation waveform of the DF converter station after the three-phase short-circuit fault at the fault point B according to an embodiment of the present application.

[0138] As shown in Fig. 4, the abscissa represents the time (in seconds) corresponding to different stages after the fault occurs, and the ordinate represents the bus voltage of the converter station, in per unit (p.u.), reflecting the transient voltage drop and recovery process. The fault point A is located at 40% of the line between the CH substation and the ZJ substation, and the fault point B is located at 5% of the line between the SZ substation and the PC substation. Figure 5a to 5d As shown in Fig. 5, the abscissa represents the time (in seconds) corresponding to different stages after the fault occurs, and the ordinate represents the bus voltage of the converter station, in per unit (p.u.), reflecting the transient voltage drop and recovery process. The fault point A is located at 40% of the line between the CH substation and the ZJ substation, and the fault point B is located at 5% of the line between the SZ substation and the PC substation.

[0139] Figure 5a As can be seen from Fig. 4, the waveform of combination 2 is obviously better than the waveforms of combination 3 and combination 6 in terms of the bus voltage drop and recovery speed. The waveform of combination 6 shows that there is a large reactive power shortage in the sub-transient stage and the transient stage after the DC system fault, i.e., the reactive power compensation cannot keep up with the reactive power consumption, and the reactive power is continuously consumed in the recovery stage after the fault is removed. Combination 3 is to install a 300 MVar capacity phase modifier in the LM converter station, but the waveform is only slightly better than that of combination 6, and the transient voltage stability is obviously insufficient compared with combination 2.

[0140] As can be seen from Fig. 5, the waveforms of combination 2 and combination 3 are both better than the waveform of combination 6. Figure 5b As can be seen from Fig. 5, the waveforms of combination 2 and combination 3 are both better than the waveform of combination 6.

[0141] Figure 5c As can be seen from Fig. 5, the waveforms of combination 2 and combination 3 are relatively close, and both can recover to the bus voltage level before the fault. At the same time, Figure 5d In combination 6, continuous commutation failure occurs, the voltage fluctuates greatly and drops below the critical stable voltage of the dynamic load, thereby causing the slip of the induction motor in the dynamic load to increase, leading to motor stall and causing transient voltage instability. Figure 5d In addition, a comparison between combination 2 and combination 3 shows that combination 2 is to install a phase modifier in the BA converter station, and combination 3 is to install a phase modifier in the LM converter station. Therefore, combination 2 is better than combination 3 in terms of the bus voltage drop and recovery speed of the BA converter station, and vice versa, combination 3 is better than combination 2 in terms of the bus voltage drop and recovery speed of the LM converter station.

[0142]

[0143] ​​​In order to verify the universality of the determination method of the converter station parameters of the embodiment of the application for different working conditions, the following will analyze and compare the transient voltage variation under four working conditions of the rated power conversion operation mode, the switching of the DC filter, the commutation failure and the short circuit fault respectively. Figure 6a to 6d The variation waveform of the target system node voltage with time under the rated power conversion operation mode working condition according to the embodiment of the application is shown.

[0144] Figure 6a The variation waveform of the target system node voltage with time under the rated power conversion operation mode working condition according to the embodiment of the application is shown.

[0145] Figure 6b The variation waveform of the target system node voltage with time under the rated power conversion operation mode working condition according to the embodiment of the application is shown.

[0146] Figure 6c The variation waveform of the target system node voltage with time under the rated power conversion operation mode working condition according to the embodiment of the application is shown.

[0147] Figure 6d The variation waveform of the target system node voltage with time under the rated power conversion operation mode working condition according to the embodiment of the application is shown.

[0148] As shown in Figure 6a to 6d , the abscissa is the time corresponding to different stages (unit: s), and the ordinate represents the node voltage (unit: p.u.), which is used to reflect the process of the node voltage drop and recovery with time. It can be known by comparison that, Figure 6a and Figure 6b , the installation position of the phase modifier in the converter station does not affect the transient voltage stability, that is, different phase modifier configuration combinations only affect the recovery speed of the node voltage. And Figure 6c and Figure 6d , the transient voltage instability occurs in the phase modifier configuration combination 6 without the phase modifier, the transient voltage stability of the phase modifier configuration combination 3 can just meet the transient voltage stability, but the transient voltage stability safety redundancy is less, and the transient voltage stability safety redundancy of the combination 2 is more, that is, the transient voltage stability margin is higher, so the transient voltage support strength is the highest.

[0149] According to the embodiment of the application, taking the constant UHVDC transmission power as 5000MW and the AC short circuit ratio as 2.4 as an example, the access proportion of the dynamic load (hereinafter referred to as the dynamic load proportion) can be 60% to 65%. For each converter station, as the dynamic load access proportion increases, the critical stable voltage parameter also increases, so in order to meet the demand for reactive power compensation to ensure the transient voltage stability of the system, a higher target total capacity is required, and for the case that the capacity of a single phase modifier is fixed, more phase modifiers need to be installed.

[0150] According to the embodiment of the present application, the correspondence between the installation capacity of the phase modifier and the dynamic load access ratio can be shown in Table 2 as follows.

[0151] Table 2

[0152]

[0153] The following takes the dynamic load ratio of 60% as an example, simulates the same converter station according to different phase modifier configuration combinations, and explains the simulation results through Figure 7a and Figure 7b .

[0154] Figure 7a Fig. 6 shows the reactive power compensation and reactive power demand of different phase modifier configuration combinations according to the embodiment of the present application over time.

[0155] As shown in Figure 7a , the abscissa represents the time corresponding to different stages (unit: s), and the ordinate represents the reactive power (unit: p.u.).

[0156] Figure 7b Fig. 7 shows the slip of different phase modifier configuration combinations according to the embodiment of the present application over time.

[0157] As shown in Figure 7b , the abscissa represents the time corresponding to different stages (unit: s), and the ordinate represents the slip (unit: p.u.).

[0158] It can be seen from the comparison that, when no phase modifier is accessed, the reactive power demand is not compensated due to continuous commutation failure of the DC, resulting in continuous increase of the slip of the dynamic load, causing system instability. After installing one phase modifier, the phase modifier reaches nearly 2.3 times of reactive power compensation by strong excitation, but still cannot meet the reactive power demand caused by the reactive power consumption of the converter, so that the bus voltage parameter is lower than the critical stability voltage parameter of the dynamic load, causing system instability. After installing two phase modifiers, the target total capacity of the converter station is improved, and the strong excitation reaches 3.9 times of reactive power compensation to meet the reactive power demand caused by the reactive power consumption of the converter. After the fault is removed, the slip gradually decreases to 0, and the system returns to the state before the fault. The simulation results are consistent with the above calculation, so the optimal phase modifier configuration combination obtained by the determination method of the converter station parameters of the embodiment of the present application has certain reliability and accuracy under different dynamic load ratios.

[0159] According to the embodiment of the present application, by coupling bus voltage parameters in different stages, dynamically constraining target configuration parameters according to bus voltage stability constraints and reactive power compensation constraints, and considering transient voltage stability and economic cost of optimal configuration combination of the phase modifier, certain technical support is provided for planning and operation of the hybrid power grid, and development and progress of the power system in the direction of reactive power compensation and transient stability are promoted.

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

[0161] As shown in Figure 8 The determination device 800 includes a obtaining module 810, a function constructing module 820, a constraint constructing module 830 and a solving module 840.

[0162] The obtaining module 810 is configured to obtain a critical stability voltage parameter of a dynamic load associated with the converter station according to a mechanical torque and an electromagnetic torque of the dynamic load corresponding to a critical stability state, and a rotor motion equation from a rated operating condition to a critical stability state operating condition.

[0163] The function constructing module 820 is configured to construct a stability sub-objective function for characterizing transient voltage stability of a target system according to bus voltage parameters and the critical stability voltage parameters of the dynamic load associated with the converter station in different stages, and construct an economic cost sub-objective function of the target system according to respective installation positions and capacities of different phase modifiers in multiple converter stations in the target system, wherein the different stages include a sub-transient stage, a transient stage and a post-fault removal stage.

[0164] The constraint constructing module 830 is configured to construct a reactive power compensation constraint and a bus voltage stability constraint of the target system according to the critical stability voltage parameter.

[0165] The solving module 840 is configured to solve an optimal configuration combination of the phase modifier 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 respective target configurations of the multiple converter stations in the target system.

[0166] According to the embodiment of the present application, the function constructing module 820 includes a first constructing sub-module and a second constructing sub-module.

[0167] The first constructing sub-module is configured to construct the stability sub-objective function according to integrals of 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 post-fault removal stage, respectively.

[0168] The second constructing submodule is configured to construct an economic cost sub-objective function based on respective installation positions and capacities of different phase-modulating machines in the plurality of converter stations.

[0169] According to an embodiment of the present application, the obtaining module 810 comprises a constructing submodule and a simultaneous solving submodule.

[0170] The constructing submodule is configured to construct a torque balance equation according to the mechanical torque and the electromagnetic torque corresponding to the critical stable state.

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

[0172] According to an embodiment of the present application, the constraint constructing module 830 comprises an obtaining submodule, an obtaining submodule and a first constraint constructing submodule.

[0173] The obtaining submodule is configured to respectively obtain rated parameters of the converter and the static reactive compensator.

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

[0175] The first constraint constructing submodule is configured to construct a reactive compensation constraint of the target system according to the rated reactive output and the reactive consumption threshold.

[0176] According to an embodiment of the present application, the constraint constructing module comprises a first constructing unit, a second constructing unit, an obtaining unit and a third constructing unit.

[0177] The first constructing unit is configured to construct a respective reactive compensation constraint of the plurality of converter stations according to the rated reactive output and the reactive consumption threshold.

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

[0179] According to an embodiment of the present application, the constraint constructing module 830 further comprises a second constraint constructing submodule, an obtaining submodule and a third constraint constructing submodule.

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

[0181] The obtaining submodule is configured to obtain a rated voltage parameter of the converter before the fault.

[0182] The third constraint construction submodule is configured to construct a second bus voltage constraint 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 time points, wherein the target time points are any time points in different stages.

[0183] According to an embodiment of the present application, the solving module 840 comprises a construction submodule, a determination submodule and an output submodule.

[0184] The construction submodule is configured to construct 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 of the SVC.

[0185] The determination submodule is configured to determine a plurality of candidate SVC configuration combinations according to the target configuration function, the reactive power compensation constraint and the bus voltage stability constraint.

[0186] The output submodule is configured to solve the optimal configuration combination of the SVC according to the plurality of candidate SVC configuration combinations, and output the respective target configuration parameters of the plurality of converter stations in the target system.

[0187] According to an embodiment of the present application, the output submodule comprises a obtaining unit and a determination unit.

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

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

[0190] Any one or more of the modules, submodules, units and subunits according to the embodiments of the present application, or at least part of the functions of any one or more of them, can be implemented in one module. Any one or more of the modules, submodules, units and subunits according to the embodiments of the present application can be split into multiple modules for implementation. Any one or more of the modules, submodules, units and subunits according to the embodiments of the present application 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 chip, a system on board, a system on package, an application specific integrated circuit (ASIC), or any other reasonable hardware or firmware that can be integrated or packaged with a circuit, or implemented in any one of software, hardware and firmware or in an appropriate combination of any one or more of them. Alternatively, one or more of the modules, submodules, units and subunits according to the embodiments of the present application can be at least partially implemented as computer program modules that can perform corresponding functions when executed.

[0191] For example, any of the obtaining module 810, the function building module 820, the constraint building module 830 and the solving module 840 can be combined in one module / unit / sub-unit, or any of the modules / units / sub-units can be split into multiple modules / units / sub-units. Alternatively, at least part of the function of one or more of the modules / units / sub-units can be combined with at least part of the function of other modules / units / sub-units, and implemented in one module / unit / sub-unit. According to an embodiment of the present application, at least one of the obtaining module 810, the function building module 820, the constraint building 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 chip, a system on board, a system in package, an application specific integrated circuit (ASIC), or any other reasonable way of integrating or packaging a circuit, etc. in hardware or firmware, or in any one of the three implementation ways of software, hardware and firmware, or in a proper combination of any of the several ways. Alternatively, at least one of the obtaining module 810, the function building module 820, the constraint building module 830 and the solving module 840 can be at least partially implemented as a computer program module which, when executed, can perform the corresponding function.

[0192] It should be noted that the determination device for the converter station parameter for improving transient voltage stability in the embodiments of the present application corresponds to the determination method for the converter station parameter for improving transient voltage stability in the embodiments of the present application, and the description of the device part is specifically referred to the method part, which will not be repeated here.

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

[0194] Figure 9 The electronic device shown is only an example, and should not bring any limitation to the function and use range of the embodiments of the present application.

[0195] As Figure 9As shown, the electronic device 900 according to an embodiment of the present application includes a processor 901 which can perform various appropriate actions and processes in accordance with a program stored in a read only memory (ROM) 902 or a program loaded from a storage section 908 into a random access memory (RAM) 903. The processor 901 can include, for example, a general purpose microprocessor (e.g., a CPU), an instruction set processor, and / or a related chip set, and / or a special purpose microprocessor (e.g., an application specific integrated circuit (ASIC)), and so on. The processor 901 can also include an on-board memory for cache use. The processor 901 can include a single processing unit or multiple processing units to perform the various actions of the method processes according to embodiments of the present application.

[0196] In the RAM 903, various programs and data required for the operation of the electronic device 900 are stored. The processor 901, the ROM 902, and the RAM 903 are connected to each other via a bus 904. The processor 901 performs various operations of the method processes according to embodiments of the present application by executing the programs in the ROM 902 and / or the RAM 903. Note that the programs can also be stored in one or more memories other than the ROM 902 and the RAM 903. The processor 901 can also perform various operations of the method processes according to embodiments of the present application by executing the programs stored in the one or more memories.

[0197] According to an embodiment of the present application, the electronic device 900 can also include an input / output (I / O) interface 905 which is also connected to the bus 904. The electronic device 900 can also include one or more of the following components connected to the input / output (I / O) interface 905: an input section 906 including a keyboard, a mouse, etc.; an output section 907 including a display such as a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 908 including a hard disk, etc.; and a communication section 909 including a network interface card such as a LAN card, a modem, etc. The communication section 909 performs communication processing via a network such as the Internet. A drive 910 is also connected to the input / output (I / O) interface 905 as necessary. A removable recording medium 911 such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc. is attached to the drive 910 as necessary, so that a computer program read out therefrom is installed in the storage section 908 as necessary.

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

[0199] The present application also provides a computer-readable storage medium, which can be included in the device / apparatus / system described in the above embodiments, or exist separately without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, which, when executed, implement the method according to the embodiments of the present application.

[0200] According to an embodiment of the present application, the computer-readable storage medium can be a non-volatile computer-readable storage medium. For example, it can include but is not limited to a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any appropriate combination thereof. In the present application, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus, or device.

[0201] For example, according to an embodiment of the present application, the computer-readable storage medium can include one or more memories of 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] The embodiments of the present application also include a computer program product comprising a computer program containing program code for executing the method provided by the embodiments of the present application, which, when the computer program product is run on an electronic device, is used to make the electronic device implement the block diagram of the electronic device for determining the converter station parameter for improving transient voltage stability provided by the embodiments of the present application.

[0203] When the computer program is executed by the processor 901, the above-described functions defined in the system / apparatus of the embodiments of the present application are performed. According to the embodiments of the present application, the system, apparatus, module, unit, etc. described above can be implemented by using the computer program module.

[0204] In one embodiment, the computer program can be stored in a tangible storage medium, such as a compact disc, a memory stick, etc. In another embodiment, the computer program can also be transmitted in a signal form, over a network medium, and be downloaded and installed by the communication part 909, and / or be installed from the detachable medium 911. The program code contained in the computer program can be transmitted by using any appropriate network medium, including but not limited to wireless, wire, etc., or any appropriate combination of the above.

[0205] According to the embodiments of the present application, the program code for performing the computer program provided by the embodiments of the present application can be written in any combination of one or more programming languages, and specifically, these computer programs can be implemented by using a high-level procedural and / or object-oriented programming language, and / or an assembly / machine language. The programming language includes but is not limited to, for example, Java, C++, python, “C” language, or similar programming languages. The program code can be executed completely on the user computing device, partially on the user device, partially on a remote computing device, or completely on a remote computing device or server. In the case involving a remote computing device, the remote computing device can be connected to the user computing device through any kind 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, connected to the Internet by using an Internet service provider).

[0206] The computer program product of the present application can be a computer program product that comprises a computer-readable medium having stored thereon instructions that can be executed by a processor of a computer to cause the processor to perform steps of any of the above-described methods of the present application. Those of skill would further appreciate that the various illustrative logical blocks, modules, processors, means, circuits, and algorithm steps described in connection with the implementations disclosed herein can be implemented as electronic hardware, computer software, or combinations of both. The

[0207] The above-described embodiments of the application have been described in connection with what are presently considered to be the most practical and preferred implementations. However, the application should not be construed as limited to the descriptions set forth herein. To the contrary, the present description is intended to cover various and numerous modifications as can be prompted by a consideration of this disclosure, and the practice of the application. For example, the various embodiments described above can be combined in any combination. Accordingly, it is expressly intended that all such modifications, enhancements, permutations, and combinations that do not depart from the spirit and scope of the present application be included within its scope, which is assessed by the appended claims.

Claims

1. A method for determining converter station parameters to improve transient voltage stability, characterized in that, The converter station includes a synchronous condenser, and the method includes: Based on the mechanical torque and electromagnetic torque of the dynamic load corresponding to the critical stable state, and the rotor motion equations for the transition from rated operating conditions to the critical stable state, the critical stable voltage parameters of the dynamic load associated with the converter station are obtained. Based on the bus voltage parameters of the converter station at 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. Based on the installation location and capacity of different synchronous condensers in the multiple converter stations of the target system, an economic cost sub-objective function of the target system is constructed. The different stages include the sub-transient stage, the transient stage, and the recovery stage after fault clearing. Based on the critical stability voltage parameters, the reactive power compensation constraints and bus voltage stability constraints of the target system are constructed. 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 synchronous condensers 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 process involves constructing a stability sub-objective function to characterize the transient voltage stability of the target system based on the bus voltage parameters of the converter stations at different stages and the critical stable voltage parameters of the associated dynamic loads. It also involves constructing an economic cost sub-objective function for the target system based on the installation location and capacity of different synchronous condensers in the multiple converter stations within the target system. This includes: The stability sub-objective function is constructed based on the integrals of the differences between the bus voltage parameters and the critical stable voltage parameters of each of the multiple converter stations during the sub-transient phase, the transient phase, and the recovery phase after fault clearing. Based on the installation location and capacity of the different synchronous condensers in the multiple converter stations, the economic cost sub-objective function is constructed.

3. The method according to claim 1, characterized in that, The critical stability voltage parameters of the dynamic load associated with the converter station are obtained based on the mechanical and electromagnetic torques of the dynamic load corresponding to the critical stability state, and the rotor motion equations for the transition from rated operating conditions to the critical stability state. This includes: Based on the mechanical torque and electromagnetic torque corresponding to the critical steady state, construct the torque balance equation; By combining the torque balance equation and the rotor motion equation, the critical stable voltage parameter is obtained.

4. The method according to claim 3, characterized in that, The converter station also includes converters and static var compensators (SVCs). The process of constructing reactive power compensation constraints and bus voltage stability constraints for the target system based on the critical stability voltage parameters includes: Obtain the rated parameters of the converter and the static var compensator respectively; Based on the rated parameters, the rated reactive power output of the static var compensator and the reactive power consumption threshold of the converter are obtained respectively. Based on the rated reactive power output and the reactive power consumption threshold, the reactive power compensation constraints of the target system are constructed.

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

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 bus voltage stability constraint of the target system based on the critical stability voltage parameter includes: Based on the critical stability voltage parameter, a first bus voltage constraint is constructed so that the bus voltage parameter at each of the different stages is greater than the critical stability voltage parameter. Obtain the rated voltage parameters of the converter station before the fault; The second bus voltage constraint is constructed based on the rated voltage parameters of the converter station before the fault and multiple predetermined constraint multiples corresponding to multiple target times, wherein the target time is any time within the different stages.

7. The method according to claim 5, characterized in that, The optimal configuration combination of synchronous condensers is solved 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 the target configuration parameters of multiple converter stations in the target system are output, including: Based on the Euclidean distance between the stability sub-objective function and the economic cost sub-objective function, construct the objective allocation function of the target system; Based on the target configuration function, the reactive power compensation constraint, and the bus voltage stability constraint, multiple candidate synchronous condenser configuration combinations are determined; Based on the multiple candidate synchronous condenser configuration combinations, the optimal configuration combination of the synchronous condensers is solved, 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, The step of solving for the optimal configuration combination of the synchronous condensers based on the multiple candidate synchronous condenser configuration combinations, and outputting the target configuration parameters of each of the multiple converter stations in the target system, includes: The target total capacity of the target system is obtained based on the reactive power compensation constraints of the converter station, the bus voltage stability constraints, and the proportional parameters of the dynamic load. Based on the target total capacity, a plurality of target camera configuration combinations are determined from the plurality of candidate camera configuration combinations; The target configuration function is solved to determine the optimal configuration combination of the synchronous condensers from the plurality of target synchronous condenser configuration combinations, and the target configuration parameters of each of the plurality of 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 camera convergence configuration combination from the plurality of target camera convergence configuration combinations includes: The target configuration function values ​​corresponding to each of the multiple target camera configuration combinations are sorted to obtain the sorting result; Based on the sorting results, the optimal configuration combination of the camera shifters is determined.

10. A device for determining converter station parameters to improve transient voltage stability, characterized in that, include: The module is used to obtain the critical stable 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 stable state, and the rotor motion equations for the transition from rated operating conditions to critical stable state operating conditions. The function construction module is used to construct a stability sub-objective function to characterize the transient voltage stability of the target system based on the bus voltage parameters and the critical stable voltage parameters of the associated dynamic load when the converter station is in different stages, and to construct an economic cost sub-objective function of the target system based on the installation location and capacity of different synchronous condensers in the multiple converter stations in the target system. The different stages include the sub-transient stage, the transient stage, and the recovery stage after fault clearing. The constraint construction module is used to construct the reactive power compensation constraint and bus voltage stability constraint of the target system based on the critical stability voltage parameters. The solution module is used to solve for the optimal configuration combination of synchronous condensers 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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