Power system inertia monitoring method and device, electronic equipment and storage medium

Abstract

The application provides a power system inertia monitoring method and device, electronic equipment and a storage medium, wherein the power system inertia monitoring method is applied to a multi-machine power system, and the power system inertia monitoring method comprises the following steps: performing electromechanical oscillation mode identification on the multi-machine power system to obtain a plurality of identified oscillation modes; determining a target oscillation mode based on the identified oscillation modes; dividing the multi-machine power system into a first system area and a second system area based on the target oscillation mode, wherein the multi-machine power system is equivalent to a two-machine interconnected system based on the first system area and the second system area; determining the transmission power and the power angle difference of the two-machine interconnected system based on the first system area and the second system area; determining the equivalent system inertia of the two-machine interconnected system based on the transmission power and the power angle difference; and determining the system inertia of the multi-machine power system based on the equivalent system inertia. The system inertia of the power system can be monitored in real time through the application.

Description

Technical Field

[0001] The present invention relates to the field of inertia monitoring technology, and in particular to a method, device, electronic equipment and storage medium for monitoring inertia of a power system. Background Art

[0002] New energy sources such as wind power and photovoltaics that use power electronic interfaces do not have the rotational inertia and primary frequency regulation capabilities of traditional synchronous machines. Large-scale access and replacement of synchronous machines will lead to a decrease in system inertia and primary frequency regulation capabilities, and a decrease in the system's ability to resist power disturbances and stability characteristics, posing a huge challenge to system frequency security.

[0003] In power systems with a high proportion of renewable energy, the random fluctuations of renewable energy sources complicate system operation. The number of synchronous generators connected to the grid can fluctuate significantly, and the time-varying nature of system inertia becomes more pronounced. Therefore, accurately and real-time understanding of the system's true inertia at every moment is crucial for assessing system frequency security and preventing frequency incidents.

[0004] Currently, finding a method to monitor the system inertia of power systems has become a research hotspot. Summary of the Invention

[0005] The present invention provides a power system inertia monitoring method, device, electronic equipment and storage medium, which can realize real-time monitoring of the system inertia of the power system, providing a basis for accurately evaluating the system frequency safety and preventing frequency accidents.

[0006] The present invention provides a power system inertia monitoring method, which is applied to a multi-machine power system. The power system inertia monitoring method comprises: performing electromechanical oscillation mode identification on the multi-machine power system to obtain multiple identified oscillation modes; determining a target oscillation mode based on the identified oscillation modes; dividing the multi-machine power system into a first system area and a second system area based on the target oscillation mode, wherein the multi-machine power system is equivalent to a two-machine interconnected system based on the first system area and the second system area; determining a transmission power and a power angle difference of the two-machine interconnected system based on the first system area and the second system area; determining an equivalent system inertia of the two-machine interconnected system based on the transmission power and the power angle difference; and determining the system inertia of the multi-machine power system based on the equivalent system inertia.

[0007] According to a power system inertia monitoring method provided by the present invention, determining the target oscillation mode based on the identified oscillation mode specifically includes: calculating the clustering value of each of the identified oscillation modes based on a clustering algorithm, and determining the identified oscillation mode corresponding to the maximum clustering value as the target oscillation mode.

[0008] According to a power system inertia monitoring method provided by the present invention, determining the transmission power of the two-machine interconnected system based on the first system area and the second system area specifically includes: determining an inter-regional tie line bus based on the first system area and the second system area; determining an inter-regional tie line corresponding to the inter-regional tie line bus based on the inter-regional tie line bus; and determining the transmission power of the two-machine interconnected system based on the sum of the transmission powers on all the inter-regional tie lines.

[0009] According to a method for monitoring inertia of a power system provided by the present invention, the inter-regional interconnection line includes a first inter-regional interconnection line in the first system area and a second inter-regional interconnection line in the second system area; the inter-regional interconnection line bus includes a first inter-regional interconnection line bus in the first system area and a second inter-regional interconnection line bus in the second system area; the determining of the power angle difference of the two-machine interconnection system based on the first system area and the second system area specifically includes: when the number of units in the first system area is less than the number of units in the second system area, using the export bus of the units in the first system area as the first inter-regional interconnection line bus; determining the second inter-regional interconnection line bus based on the first inter-regional interconnection line bus; determining the first inter-regional interconnection line based on the first inter-regional interconnection line bus; determining the output angle difference of the two-machine interconnection system based on the second inter-regional interconnection line bus. The second inter-regional interconnection line; respectively determine the first voltage average of the first inter-regional interconnection line bus of the first system area at the current moment and the previous moment, and the second voltage average of the second inter-regional interconnection line bus of the second system area at the current moment and the previous moment; respectively determine the sum of the first outflow current of the first inter-regional interconnection line of the first system area at the current moment and the previous moment, and the sum of the second outflow current of the second inter-regional interconnection line of the second system area at the current moment and the previous moment; determine the first Thevenin equivalent parameter of the first system area based on the first voltage average and the sum of the first outflow current; determine the second Thevenin equivalent parameter of the second system area based on the sum of the second voltage average and the second outflow current; determine the power angle difference of the two-machine interconnection system based on the first Thevenin equivalent parameter and the second Thevenin equivalent parameter.

[0010] According to a power system inertia monitoring method provided by the present invention, the first Thevenin equivalent parameter includes one of the first Thevenin equivalent parameters and a second of the first Thevenin equivalent parameters; and determining the first Thevenin equivalent parameter of the first system area based on the sum of the first voltage average and the first outflow current is implemented using the following formula:

[0011] E1，re，k =V 1，re，k -I 1，im，k x 1，k ;

[0012] E 1，imm，k =V 1，im，k -I 1，re，k x 1，k ;

[0013] E 1，re，k-1 =V 1，re，k-1 -I 1，im，k-1 x 1，k-1 ;

[0014] E 1，im，k-1 =V 1，im，k-1 -I 1，re，k-1 x 1，k-1 ;

[0015]

[0016]

[0017] Among them, E 1，re，k represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k; E 1，im，k represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k; x 1，k represents the second first Thevenin equivalent parameter of the first system region at time k; E 1，re，k-1 represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k-1; E 1，im，k-1 represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k-1; x 1，k-1 represents the second first Thevenin equivalent parameter of the first system region at time k-1; V 1，re，k represents the real part of the first voltage mean value at time k; V 1，im，k represents the imaginary part of the first voltage mean value at time k; I 1，re，k represents the real part of the sum of the first outflow currents at time k; I 1，im，k represents the imaginary part of the sum of the first outflow currents at time k; I 1，re，k-1 represents the real part of the sum of the first outflow currents at time k-1; I 1，im，k-1 represents the imaginary part of the sum of the first outflow currents at time k-1.

[0018] According to a power system inertia monitoring method provided by the present invention, the second Thevenin equivalent parameter includes one of the second Thevenin equivalent parameters and a second of the second Thevenin equivalent parameters; and determining the second Thevenin equivalent parameter of the second system area based on the sum of the second voltage average and the second outflow current is implemented using the following formula:

[0019] E 2，re，k =V 2，re，k -I 2，im，k x 2，k ;

[0020] E 2，im，k =V 2，im，k -I 2，re，k x 2，k ;

[0021] E 2，re，k-1 =V 2，re，k-1 -I 2，im，k-1 x 2，k-1 ;

[0022] E 2，im，k-1 =V 2，im，k-1 -I 2，re，k-1 x 2，k-1 ;

[0023]

[0024]

[0025] Among them, E 2，re，k represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k; E 2，im，k represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k; x 2，k represents the second Thevenin equivalent parameter 2 of the second system region at time k; E 2，re，k-1 represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k-1; E 2，im，k-1 represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k-1; x 2，k-1 V represents the second Thevenin equivalent parameter of the second system region at time k-1; 2，re，k represents the real part of the second voltage mean value at time k; V 2，im，k represents the imaginary part of the second voltage mean value at time k; I 2，re，k represents the real part of the sum of the second outflow currents at time k; I 2，im，k represents the imaginary part of the sum of the second outflow currents at time k; I 2，re，k-1represents the real part of the sum of the second outflow currents at time k-1; I 2，im，k-1 represents the imaginary part of the sum of the second outflow currents at time k-1.

[0026] According to a power system inertia monitoring method provided by the present invention, the first Thevenin equivalent parameter includes one of the first Thevenin equivalent parameters, and the second Thevenin equivalent parameter includes one of the second Thevenin equivalent parameters; and the power angle difference of the two-machine interconnected system is determined based on the first Thevenin equivalent parameter and the second Thevenin equivalent parameter, and is implemented by the following formula:

[0027]

[0028] Wherein, δ0 represents the power angle difference; E 1，im，k represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k; E 1，re，k represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k; E 2，im，k represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k; E 2，re，k represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k.

[0029] According to a power system inertia monitoring method provided by the present invention, determining the equivalent system inertia of the two-machine interconnected system based on the transmission power and the power angle difference specifically includes: determining the rated angular velocity of the rotor of the multi-machine power system; determining a target eigenvalue corresponding to the target oscillation mode; and determining the equivalent system inertia of the two-machine interconnected system based on the target eigenvalue, the rated angular velocity, the transmission power, and the power angle difference.

[0030] According to a power system inertia monitoring method provided by the present invention, determining the system inertia of the multi-machine power system based on the equivalent system inertia specifically includes: determining a first right eigenvector mean, wherein the first right eigenvector mean is the average value of the right eigenvectors corresponding to the respective units in the first system area; determining a second right eigenvector mean, wherein the second right eigenvector mean is the average value of the right eigenvectors corresponding to the respective units in the second system area; determining a first inertia of the first system area and a second inertia of the second system area based on the first right eigenvector mean, the second right eigenvector mean, the target eigenvalue, and the equivalent system inertia; and determining the system inertia of the multi-machine power system based on the sum of the first inertia and the second inertia.

[0031] The present invention also provides an electric power system inertia monitoring device, which is applied to a multi-machine electric power system. The electric power system inertia monitoring device includes: a first module for performing electromechanical oscillation mode identification on the multi-machine electric power system to obtain multiple identified oscillation modes; a second module for determining a target oscillation mode based on the identified oscillation mode; a third module for dividing the multi-machine electric power system into a first system area and a second system area based on the target oscillation mode, wherein the multi-machine electric power system is equivalent to a two-machine interconnected system based on the first system area and the second system area; a fourth module for determining the transmission power and power angle difference of the two-machine interconnected system based on the first system area and the second system area; a fifth module for determining the equivalent system inertia of the two-machine interconnected system based on the transmission power and the power angle difference; and a sixth module for determining the system inertia of the multi-machine electric power system based on the equivalent system inertia.

[0032] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the power system inertia monitoring method as described above is implemented.

[0033] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for monitoring inertia of a power system as described above is implemented.

[0034] The present invention also provides a computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the computer program implements any one of the above-described methods for monitoring inertia of a power system.

[0035] The power system inertia monitoring method, device, electronic device and storage medium provided by the present invention are applied to a multi-machine power system. By identifying the electromechanical oscillation mode of the multi-machine power system, a plurality of identified oscillation modes are obtained, and then a target oscillation mode is determined based on the identified oscillation mode; based on the target oscillation mode, the multi-machine power system is divided into a first system area and a second system area, and the multi-machine power system is equivalent to a two-machine interconnected system. The equivalent system inertia of the two-machine interconnected system is calculated, and then the system inertia of the multi-machine power system is determined based on the equivalent system inertia. The present invention provides a complete identification process, which can monitor the system inertia of the new energy power system in real time based on the measurement data during the operation of the multi-machine power system, providing a basis for accurately evaluating the system frequency safety and preventing frequency accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 1 is a flow chart of the method for monitoring inertia of a power system provided by the present invention;

[0038] Figure 2 It is a structural diagram of the system area provided by the present invention;

[0039] Figure 3 This is a flow chart of determining the transmission power of a two-machine interconnection system based on a first system area and a second system area provided by the present invention;

[0040] Figure 4 1 is a flow chart of determining a power angle difference between two interconnected systems based on a first system area and a second system area, as provided by the present invention;

[0041] Figure 5 This is a flow chart of determining the equivalent system inertia of a two-machine interconnection system based on transmission power and power angle difference, as provided by the present invention;

[0042] Figure 6 It is a schematic diagram of a flow chart for determining the system inertia of a multi-machine power system based on equivalent system inertia provided by the present invention;

[0043] Figure 7 It is a wiring diagram of the IEEE39 node system provided by the present invention;

[0044] Figure 8 It is a structural diagram of the power system inertia monitoring device provided by the present invention;

[0045] Figure 9 It is a structural schematic diagram of the electronic device provided by the present invention.

[0046] Reference numerals:

[0047] 100: system area; 10: unit;

[0048] 20: Inter-regional interconnection line busbar; 30: Inter-regional interconnection line. DETAILED DESCRIPTION

[0049] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0050] The power system inertia monitoring method provided by the present invention is applicable to a multi-machine power system. A multi-machine power system refers to a power system with multiple generator sets (power sources). In another embodiment, the generator sets in the multi-machine power system may also include new energy generator sets.

[0051] The power system inertia monitoring method provided by the present invention can not only get rid of the dependence on models and parameters, but also overcome the limitation that continuous online monitoring cannot be achieved based on data after power disturbance, and realize online estimation of the inertia of the entire network based on measurement.

[0052] For multi-machine power systems, multiple electromechanical oscillation modes in the system are identified based on noise-like data, and a suitable interval oscillation mode is selected for inertia identification; the system is divided into two areas (corresponding to the first system area and the second system area) according to the selected interval oscillation mode, and the system is equivalent to a two-machine interconnected system. The Thevenin equivalent parameters of the two areas are calculated; the equivalent system inertia and the inertia of the two areas are calculated, and the sum of the inertia of the two areas is the system inertia. In response to the problem of inertia identification of actual complex multi-machine systems, the present invention proposes a complete identification process, which can accurately identify the system inertia based on the noise-like data measured during normal operation, providing a basis for accurately evaluating the system frequency safety and preventing frequency accidents.

[0053] In order to further introduce the power system inertia monitoring method provided by the present invention, the following will be combined with Figure 1 Provide explanation.

[0054] Figure 1 It is a flow chart of the power system inertia monitoring method provided by the present invention.

[0055] In an exemplary embodiment of the present invention, Figure 1 It can be seen that the power system inertia monitoring method may include steps 110 to 160 , and each step will be described below.

[0056] In step 110 , electromechanical oscillation mode identification is performed on the multi-machine power system to obtain a plurality of identified oscillation modes.

[0057] In one embodiment, for a multi-machine power system, electromechanical oscillation pattern identification may be performed based on noise-like data to obtain multiple identified oscillation patterns (corresponding to identified oscillation patterns).

[0058] In step 120 , a target oscillation pattern is determined based on the identified oscillation pattern.

[0059] In one embodiment, an interval oscillation pattern of obvious relative oscillation between two regional machine groups may be selected from the identified oscillation patterns as the target oscillation pattern.

[0060] In another exemplary embodiment of the present invention, based on the identified oscillation mode, determining the target oscillation mode can also be achieved in the following manner:

[0061] Based on the clustering algorithm, the clustering values ​​of the identified oscillation modes are calculated respectively, and the identified oscillation mode corresponding to the maximum clustering value is determined as the target oscillation mode.

[0062] In step 130 , the multi-machine power system is divided into a first system area and a second system area based on the target oscillation mode, wherein the multi-machine power system is equivalent to a two-machine interconnected system based on the first system area and the second system area.

[0063] In one embodiment, the multi-machine power system can be divided into two regions according to the target oscillation mode, namely a first system region and a second system region. It should be noted that based on the first system region and the second system region, the multi-machine power system can be equivalent to a two-machine interconnected system.

[0064] Figure 2 It is a structural diagram of the system area provided by the present invention.

[0065] in, Figure 2 The system area 100 shown can represent the first system area or the second system area. The system area 100 can include multiple units 10. In one example, each system area can be determined based on the first system area and the second system area (which can be used to Figure 2 The system area 100 in FIG. 1 corresponds to the inter-regional busbar 20 and the inter-regional tie line 30. The specific determination process will be described below.

[0066] It should be noted that Figure 2 P in e It can represent the transmission power transmitted on the inter-regional tie line 30.

[0067] In step 140, based on the first system area and the second system area, the transmission power and power angle difference of the two-machine interconnection system are determined.

[0068] In step 150 , the equivalent system inertia of the two-machine interconnected system is determined based on the transmission power and the power angle difference.

[0069] In step 160 , the system inertia of the multi-machine power system is determined based on the equivalent system inertia.

[0070] In one embodiment, the transmission power and power angle difference of the two-machine interconnected system can be determined based on the first and second system areas. The equivalent system inertia of the two-machine interconnected system can then be determined based on the transmission power and power angle difference. Furthermore, the system inertia of the multi-machine power system can be determined based on the equivalent system inertia. In this embodiment, the system inertia of the new energy power system can be determined in real time based on the equivalent system inertia of the two-machine interconnected system, providing a basis for accurately assessing system frequency security and preventing frequency accidents.

[0071] In order to further introduce the power system inertia monitoring method provided by the present invention, the following will be combined with Figure 3 Provide explanation.

[0072] Figure 3 It is a flow chart of determining the transmission power of a two-machine interconnection system based on a first system area and a second system area provided by the present invention.

[0073] In an exemplary embodiment of the present invention, Figure 3 It can be seen that determining the transmission power of the two-machine interconnection system based on the first system area and the second system area may include steps 310 to 330, and each step will be described below.

[0074] In step 310, an inter-region tie line bus is determined based on the first system area and the second system area.

[0075] In one embodiment, an inter-regional tie line busbar may be determined based on the first system area and the second system area, wherein the inter-regional tie line busbar may include a first inter-regional tie line busbar of the first system area and a second inter-regional tie line busbar of the second system area.

[0076] In step 320, based on the inter-regional tie line bus, an inter-regional tie line corresponding to the inter-regional tie line bus is determined.

[0077] In one embodiment, the inter-regional tie line may include a first inter-regional tie line in a first system area and a second inter-regional tie line in a second system area. In one example, the first inter-regional tie line in the first system area and the second inter-regional tie line in the second system area may be determined based on a first inter-regional tie line busbar in the first system area and a second inter-regional tie line busbar in the second system area, respectively.

[0078] In step 330, the transmission power of the two-machine interconnection system is determined based on the sum of the transmission powers on all inter-area tie lines.

[0079] In one embodiment, the transmission power of the two-machine interconnection system may be determined by the sum of the transmission powers on all inter-regional tie lines (including the first inter-regional tie line and the second inter-regional tie line).

[0080] In order to further introduce the power system inertia monitoring method provided by the present invention, the following will be combined with Figure 4 Provide explanation.

[0081] Figure 4 It is a flow chart of determining the power angle difference of a two-machine interconnected system based on a first system area and a second system area provided by the present invention.

[0082] In an exemplary embodiment of the present invention, Figure 4 It can be seen that determining the power angle difference of the two-machine interconnected system based on the first system area and the second system area may include steps 410 to 490, and each step will be described below.

[0083] In step 410, when the number of units in the first system area is less than the number of units in the second system area, the export busbars of the units in the first system area are used as the first inter-area tie line busbar.

[0084] It should be noted that, in this embodiment, the first system area and the second system area are not specifically limited. The first system area may be the second system area, and the second system area may also be the first system area.

[0085] As a variation, if the number of units in the second system area is smaller than that in the first system area, the outlet busbars of the units in the second system area can be used as the second inter-area tie busbars. Furthermore, the first inter-area tie busbars can be determined based on the second inter-area tie busbars.

[0086] In step 420 , a second inter-regional tie-line busbar is determined based on the first inter-regional tie-line busbar.

[0087] In one embodiment, the first system area and the second system area are connected in parallel, so the second inter-area tie-line busbar can be determined based on the first inter-area tie-line busbar.

[0088] In step 430 , a first inter-regional tie line is determined based on the first inter-regional tie line bus.

[0089] In step 440 , a second inter-regional tie line is determined based on the second inter-regional tie line bus.

[0090] In one embodiment, a first inter-regional tie line corresponding to the first inter-regional tie line busbar may be determined based on the first inter-regional tie line busbar, and a second inter-regional tie line corresponding to the second inter-regional tie line busbar may be determined based on the second inter-regional tie line busbar.

[0091] In step 450, a first average voltage value of a first inter-region tie line busbar in the first system area at the current moment and the previous moment, and a second average voltage value of a second inter-region tie line busbar in the second system area at the current moment and the previous moment are determined respectively.

[0092] In one embodiment, the first system area may include a plurality of first inter-area tie-line buses. In one example, the first voltage average of the first inter-area tie-line buses may be determined based on an average of voltage values ​​of the first inter-area tie-line buses.

[0093] In one example, the first voltage mean value of the first inter-region tie line busbar may also be determined using the following formula (1):

[0094]

[0095] in, represents the first voltage average value of the first inter-region tie line busbar. It should be noted that, is in vector form, represents the voltage value of the nth first inter-region tie-line busbar in the first system area; m represents the number of first inter-region tie-line busbars.

[0096] In another embodiment, the second system area may include multiple second inter-area tie-line buses. In one example, the second voltage average of the second inter-area tie-line buses may be determined based on an average of voltage values ​​of the second inter-area tie-line buses.

[0097] In one example, the second voltage mean value of the second inter-regional tie line busbar may also be determined using the following formula (2):

[0098]

[0099] in, represents the second voltage mean value of the second inter-regional tie line busbar. It should be noted that, is in vector form, represents the voltage value of the nth second inter-region tie-line busbar in the second system area; m represents the number of second inter-region tie-line busbars.

[0100] It should be noted that, at the first voltage average and the second voltage mean The subscripts k and k-1 indicate the first voltage mean at the current moment (i.e., moment k). and the second voltage mean And the first voltage mean value at the previous moment (i.e., moment k-1) and the second voltage mean

[0101] In step 460 , the sum of the first outflow current of the first inter-region tie line of the first system area at the current moment and the previous moment, and the sum of the second outflow current of the second inter-region tie line of the second system area at the current moment and the previous moment are determined respectively.

[0102] In one embodiment, the first system area may include a plurality of first inter-area tie lines. In one example, the sum of the first outflow currents of the first inter-area tie lines may be determined based on the sum of the outflow currents of the respective first inter-area tie lines.

[0103] In one example, the sum of the first outflow currents of the first inter-regional tie lines may also be determined using the following formula (3):

[0104]

[0105] in, represents the sum of the first outflow currents of the first inter-regional tie line. It should be noted that, is in vector form, represents the outflow current of the nth first inter-region tie line in the first system area; l represents the number of first inter-region tie lines.

[0106] In one embodiment, the second system area may include a plurality of second inter-area tie lines. In one example, the sum of the second outflow currents of the second inter-area tie lines may be determined based on the sum of the outflow currents of the respective second inter-area tie lines.

[0107] In one example, the sum of the second outflow currents of the second inter-regional tie line can also be determined using the following formula (4):

[0108]

[0109] in, represents the sum of the second outflow current of the second inter-regional tie line. It should be noted that, is in vector form, represents the outflow current of the nth second inter-region tie line in the second system area; l represents the number of second inter-region tie lines.

[0110] It should be noted that the sum of the first outflow current and the sum of the second outflow current The subscripts k and k-1 respectively represent the sum of the first outflow current at the current moment (i.e., moment k). and the sum of the second outflow current and the sum of the first outflow current at the previous moment (i.e., moment k-1) and the sum of the second outflow current

[0111] In step 470 , a first Thevenin equivalent parameter of the first system region is determined based on the sum of the first voltage average value and the first outflow current.

[0112] In one embodiment, the first Thevenin equivalent parameter may include one of the first Thevenin equivalent parameters Among them, one of the first Thevenin equivalent parameters is in vector form, And the second first Thevenin equivalent parameter x1.

[0113] It should be noted that one of the first Thevenin equivalent parameters The subscripts k and k-1 are marked on the first Thevenin equivalent parameter x1, which represent one of the first Thevenin equivalent parameters at the current time (i.e., time k). and the second of the first Thevenin equivalent parameters x1; and one of the first Thevenin equivalent parameters at the previous moment (i.e., moment k-1) And the second first Thevenin equivalent parameter x1.

[0114] In one embodiment, the first Thevenin equivalent parameter of the first system region is determined based on the sum of the first voltage average value and the first outflow current, which can be implemented using the following formulas (5)-(10):

[0115] E 1，re，k =V 1，re，k -I 1，im，k x 1，k (5)

[0116] E 1，im，k =V 1，im，k -I 1，re，k x 1，k (6)

[0117] E 1，re，k-1 =V 1，re，k-1 -I 1，im，k-1 x 1，k-1 (7)

[0118] E 1，im，k-1 =V 1，im，k-1 -I 1，re，k-1 x 1，k-1 (8)

[0119]

[0120]

[0121] Among them, E 1，re，k represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k; E 1，im，k represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k; x 1，k The second first Thevenin equivalent parameter of the first system region at time k; E 1，re，k-1 represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k-1; E 1，im，k-1 represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k-1; x 1，k-1 V represents the second first Thevenin equivalent parameter of the first system region at time k-1; 1，re，k represents the real part of the first voltage mean at time k; V 1，im，k represents the imaginary part of the first voltage mean value at time k; I 1，re，k represents the real part of the sum of the first outflow currents at time k; I 1，im，k represents the imaginary part of the sum of the first outflow currents at time k; I 1，re，k-1 represents the real part of the sum of the first outflow currents at time k-1; I 1，im，k-1 represents the imaginary part of the sum of the first outflow currents at time k-1.

[0122] In step 480 , a second Thevenin equivalent parameter of the second system region is determined based on the sum of the second voltage average and the second outflow current.

[0123] In one embodiment, the second Thevenin equivalent parameter may include one of the second Thevenin equivalent parameters Among them, one of the second Thevenin equivalent parameters is in vector form, And the second Thevenin equivalent parameter x2.

[0124] It should be noted that one of the second Thevenin equivalent parameters The second Thevenin equivalent parameter x2 is marked with subscripts k and k-1, which respectively represent one of the second Thevenin equivalent parameters at the current time (i.e., time k). and the second Thevenin equivalent parameter x2; and one of the second Thevenin equivalent parameters at the previous moment (i.e., moment k-1) And the second Thevenin equivalent parameter x2.

[0125] In one embodiment, the second Thevenin equivalent parameter of the second system region is determined based on the sum of the second voltage average and the second outflow current, which can be implemented using the following formulas (11)-(16):

[0126] E 2，re，k =V 2，re，k -I 2，im，k x 2，k (11)

[0127] E 2，im，k =V 2，im，k -I 2，re，k x 2，k (12)

[0128] E 2，re，k-1 =V 2，re，k-1 -I 2，im，k-1 x 2，k-1 (13)

[0129] E 2，im，k-1 =V 2，im，k-1 -I 2，re，k-1 x 2，k-1 (14)

[0130]

[0131]

[0132] Among them, E 2，re，k represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k; E 2，im，k represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k; x 2，k represents the second Thevenin equivalent parameter 2 of the second system region at time k; E 2，re，k-1 represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k-1; E 2，im，k-1 represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k-1; x 2，k-1 V represents the second Thevenin equivalent parameter of the second system region at time k-1; 2，re，k represents the real part of the second voltage mean at time k; V 2，im，k represents the imaginary part of the second voltage mean value at time k; I 2，re，k represents the real part of the sum of the second outflow current at time k; I 2，im，k represents the imaginary part of the sum of the second outflow current at time k; I 2,re,k-1 represents the real part of the sum of the second outflow current at time k-1; I 2,im,k-1 represents the imaginary part of the sum of the second outflow currents at time k-1.

[0133] In step 490 , a power angle difference of the two-machine interconnected system is determined based on the first Thevenin equivalent parameter and the second Thevenin equivalent parameter.

[0134] In one embodiment, based on the first Thevenin equivalent parameter and the second Thevenin equivalent parameter, the power angle difference of the two-machine interconnected system is determined, which can be achieved by using the following formula (17):

[0135]

[0136] Among them, δ0 represents the power angle difference; E 1,im,k represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k; E 1,re,k represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k; E 2,im,k represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k; E 2,re,k represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k.

[0137] Through the above-mentioned embodiments, based on the measurement data during the operation of the multi-machine power system, the power angle difference and transmission power of the two-machine interconnected system can be determined respectively, so as to further monitor the system inertia of the new energy power system in real time based on the power angle difference and transmission power, and thus provide a basis for accurately evaluating the system frequency safety and preventing frequency accidents.

[0138] Figure 5 The present invention provides a flow chart of determining the equivalent system inertia of a two-machine interconnection system based on transmission power and power angle difference.

[0139] The following will be combined Figure 5 The process of determining the equivalent system inertia of a two-machine interconnected system based on the transmitted power and power angle difference is described.

[0140] In an exemplary embodiment of the present invention, Figure 5 It can be seen that determining the equivalent system inertia of the two-machine interconnected system based on the transmission power and the power angle difference may include steps 510 to 530, and each step will be described below.

[0141] In step 510 , the rated angular speed of the rotor of the multi-machine power system is determined.

[0142] In one embodiment, the rated angular velocity ω of the rotor of the multi-machine power system can be determined n The rated angular speed of the rotor can be determined based on the rotor's factory setting data.

[0143] In step 520 , a target eigenvalue corresponding to the target oscillation mode is determined.

[0144] In one embodiment, a target characteristic value corresponding to the target oscillation mode may also be determined, and the target characteristic value is expressed as s i =a±jω d .

[0145] In step 530 , the equivalent system inertia of the two-machine interconnected system is determined based on the target characteristic value, the rated angular velocity, the transmission power, and the power angle difference.

[0146] In one embodiment, the equivalent system inertia of the two-machine interconnected system is determined based on the target characteristic value, rated angular velocity, transmission power, and power angle difference, which can be achieved using formula (18):

[0147]

[0148] Where H represents the equivalent system inertia of the two-machine interconnected system; ω n Indicates the rated angular speed of the rotor of the multi-machine power system; P e0 represents the transmission power; δ0 represents the power angle difference; a represents the real part of the target eigenvalue; ω d Represents the imaginary part of the target eigenvalue.

[0149] Figure 6 The present invention provides a flow chart of determining the system inertia of a multi-machine power system based on the equivalent system inertia.

[0150] The following will be combined Figure 6 The process of determining the system inertia of a multi-machine power system based on equivalent system inertia is described.

[0151] In an exemplary embodiment of the present invention, Figure 6 It can be seen that determining the system inertia of the multi-machine power system based on the equivalent system inertia may include steps 610 to 640 , and each step will be described below.

[0152] In step 610 , a first right eigenvector mean is determined, wherein the first right eigenvector mean is an average value of right eigenvectors corresponding to each unit in the first system area.

[0153] In step 620 , a second right eigenvector mean is determined, wherein the second right eigenvector mean is an average value of the right eigenvectors corresponding to the units in the second system area.

[0154] In one embodiment, the average value of the right eigenvectors corresponding to the units in the first system area can be determined respectively, and the average value is used as the first right eigenvector mean, which is recorded as

[0155] In another embodiment, the average value of the right eigenvector corresponding to each unit in the second system area can be determined respectively, and the average value is used as the second right eigenvector mean, which is recorded as

[0156] In step 630 , a first inertia of the first system region and a second inertia of the second system region are determined based on the first right eigenvector mean, the second right eigenvector mean, the target eigenvalue, and the equivalent system inertia.

[0157] In one embodiment, based on the first right eigenvector mean, the second right eigenvector mean, the target eigenvalue, and the equivalent system inertia, the first inertia of the first system region and the second inertia of the second system region are determined, which can be determined using the following formulas (19)-(20):

[0158]

[0159]

[0160] Where H represents the equivalent system inertia of the two-machine interconnected system; H1 represents the first inertia of the first system area; H2 represents the second inertia of the second system area; s i represents the target feature value; represents the mean of the first right eigenvector; represents the mean of the second right eigenvector.

[0161] Based on the above formulas (19)-(20), the first inertia and the second inertia can be calculated.

[0162] In step 640 , the system inertia of the multi-machine power system is determined based on the sum of the first inertia and the second inertia.

[0163] In one embodiment, the system inertia of the multi-machine power system may be determined by summing the first inertia and the second inertia, that is, the system inertia of the multi-machine power system is H1+H2.

[0164] In order to further introduce the power system inertia monitoring method provided by the present invention, the following will be described in conjunction with the IEEE39 node system.

[0165] Figure 7 This is a wiring diagram of the IEEE39 node system provided by the present invention.

[0166] Combine Figure 7 It can be seen that numbers 1 to 35 represent the numbers of the units in the IEEE 39 bus system, and G1 to G9 represent the numbers of the buses in the IEEE 39 bus system.

[0167] During the application process, electromechanical oscillation mode identification can be performed on the IEEE39 node system to identify multiple oscillation modes, and the identification can be performed according to the modes shown in Table 1.

[0168] Table 1 Inter-zone oscillation modal parameters

[0169]

[0170] Furthermore, the target oscillation mode can be determined based on the identified oscillation mode, and based on this target oscillation mode, the multi-machine power system can be divided into a first system region and a second system region. In the IEEE 39-bus system, for the selected mode, the oscillation mode is that units 1, 8, and 9 oscillate with other units in the system. Branches 26-27, 25-2, and 30-2 serve as tie lines, and the exchange power on the tie lines is P = 10.7849 pu.

[0171] Furthermore, the Thevenin equivalents of the two regions (corresponding to the first system region and the second system region) are calculated based on formulas (5) and (16), and the results are shown in Table 2.

[0172] Table 2 Equivalent system parameters

[0173]

[0174] Furthermore, the equivalent system inertia of the IEEE 39-bus system is calculated based on formula (18) to be 52.503s. The ratio of the two regional inertias (first inertia and second inertia) is then calculated based on formulas (19)-(20), HG1 / HG2 = 0.8, resulting in the inertias of the two regions: HG1 = 94.5s; HG2 = 118.125s. The sum of the two regional inertias gives the inertia of the entire system: H = 212.625s.

[0175] According to the above description, the power system inertia monitoring method provided by the present invention is applied to a multi-machine power system. By identifying the electromechanical oscillation mode of the multi-machine power system, a plurality of identified oscillation modes are obtained, and then the target oscillation mode is determined based on the identified oscillation mode; based on the target oscillation mode, the multi-machine power system is divided into a first system area and a second system area, and the multi-machine power system is equivalent to a two-machine interconnected system. The equivalent system inertia of the two-machine interconnected system is calculated, and then the system inertia of the multi-machine power system is determined based on the equivalent system inertia. The present invention provides a complete identification process, which can monitor the system inertia of the new energy power system in real time based on the measurement data during the operation of the multi-machine power system, providing a basis for accurately evaluating the system frequency safety and preventing frequency accidents.

[0176] Based on the same concept, the present invention also provides a power system inertia monitoring device.

[0177] The power system inertia monitoring device provided by the present invention is described below. The power system inertia monitoring device described below and the power system inertia monitoring method described above can be referenced to each other.

[0178] Figure 8 It is a structural schematic diagram of the power system inertia monitoring device provided by the present invention.

[0179] The following will be combined Figure 8 The power system inertia monitoring device is described.

[0180] In an exemplary embodiment of the present invention, the power system inertia monitoring device can also be applied to a multi-machine power system.

[0181] Combine Figure 8 It can be seen that the power system inertia monitoring device can include a first module 810 to a sixth module 860 , and each module will be introduced below.

[0182] The first module 810 may be configured to perform electromechanical oscillation mode identification on a multi-machine power system to obtain a plurality of identified oscillation modes;

[0183] The second module 820 may be configured to determine a target oscillation pattern based on the identified oscillation pattern;

[0184] The third module 830 may be configured to divide the multi-machine power system into a first system region and a second system region based on the target oscillation mode, wherein the multi-machine power system is equivalent to a two-machine interconnected system based on the first system region and the second system region;

[0185] The fourth module 840 may be configured to determine the transmission power and power angle difference of the two-machine interconnected system based on the first system area and the second system area;

[0186] The fifth module 850 may be configured to determine an equivalent system inertia of the interconnected system of the two machines based on the transmission power and the power angle difference;

[0187] The sixth module 860 may be configured to determine the system inertia of the multi-machine power system based on the equivalent system inertia.

[0188] In an exemplary embodiment of the present invention, the second module 820 may determine the target oscillation mode based on the identified oscillation mode in the following manner:

[0189] Based on the clustering algorithm, the clustering values ​​of the identified oscillation modes are calculated respectively, and the identified oscillation mode corresponding to the maximum clustering value is determined as the target oscillation mode.

[0190] In an exemplary embodiment of the present invention, the fourth module 840 may determine the transmission power of the two-machine interconnection system based on the first system area and the second system area in the following manner:

[0191] Determine the inter-region tie line bus based on the first system area and the second system area;

[0192] Based on the inter-regional tie line bus, determine the inter-regional tie line corresponding to the inter-regional tie line bus;

[0193] The transmission power of the two-machine interconnection system is determined based on the sum of the transmission powers on all inter-regional tie lines.

[0194] In an exemplary embodiment of the present invention, the inter-regional tie line may include a first inter-regional tie line of a first system area and a second inter-regional tie line of a second system area; the inter-regional tie line bus may include a first inter-regional tie line bus of the first system area and a second inter-regional tie line bus of the second system area;

[0195] The fourth module 840 may determine the power angle difference of the two-machine interconnected system based on the first system area and the second system area in the following manner:

[0196] When the number of units in the first system area is less than that in the second system area, the export busbars of the units in the first system area are used as the first inter-area tie line busbars;

[0197] Determining a second inter-regional tie line bus based on the first inter-regional tie line bus;

[0198] Determining the first inter-regional tie line based on the first inter-regional tie line bus;

[0199] Determining the second inter-regional tie line based on the second inter-regional tie line bus;

[0200] Determine respectively a first voltage average of a first inter-region tie line busbar in the first system area at a current moment and a previous moment, and a second voltage average of a second inter-region tie line busbar in the second system area at a current moment and a previous moment;

[0201] respectively determining a sum of a first outflow current of a first inter-regional tie line of a first system area at a current moment and a previous moment, and a sum of a second outflow current of a second inter-regional tie line of a second system area at a current moment and a previous moment;

[0202] determining a first Thevenin equivalent parameter of the first system region based on a sum of the first voltage average and the first outflow current;

[0203] determining a second Thevenin equivalent parameter of the second system region based on the second voltage mean value and the sum of the second outflow current;

[0204] Based on the first Thevenin equivalent parameter and the second Thevenin equivalent parameter, the power angle difference of the two-machine interconnection system is determined.

[0205] In an exemplary embodiment of the present invention, the first Thevenin equivalent parameter may include one of the first Thevenin equivalent parameters and two of the first Thevenin equivalent parameters;

[0206] The fourth module 840 can use the following formulas (21)-(26) to determine the first Thevenin equivalent parameter of the first system area based on the sum of the first voltage average and the first outflow current:

[0207] E 1，re，k =V 1，re，k -I 1，im，k x 1，k (twenty one)

[0208] E 1，im，k =V 1，im，k -I 1，re，k x 1，kk (twenty two)

[0209] E 1，re，k-1 =V 1，re，k-1 -I 1，im，k-1 x 1，k-1 (twenty three)

[0210] E 1，im，k-1 =V 1，im，k-1 -I 1，re，k-1 x 1，k-1 (twenty four)

[0211]

[0212]

[0213] Among them, E 1，re，k represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k; E 1，im，k represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k; x 1，k The second first Thevenin equivalent parameter of the first system region at time k; E 1，re，k-1 represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k-1; E 1，im，k-1 represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k-1; x 1，k-1 V represents the second first Thevenin equivalent parameter of the first system region at time k-1; 1，re，k represents the real part of the first voltage mean at time k; V 1，im，krepresents the imaginary part of the first voltage mean value at time k; I 1，re，k represents the real part of the sum of the first outflow currents at time k; I 1，im，k represents the imaginary part of the sum of the first outflow currents at time k; I 1，re，k-1 represents the real part of the sum of the first outflow currents at time k-1; I 1，im，k-1 represents the imaginary part of the sum of the first outflow currents at time k-1.

[0214] In an exemplary embodiment of the present invention, the second Thevenin equivalent parameter may include one of the second Thevenin equivalent parameters and two of the second Thevenin equivalent parameters;

[0215] The fourth module 840 can use the following formulas (27)-(31) to determine the second Thevenin equivalent parameter of the second system area based on the sum of the second voltage mean and the second outflow current:

[0216] E 2，re，k =V 2，re，k -I 2，im，k x 2，k (27)

[0217] E 2，im，k =V 2，im，k -I 2，re，k x 2，k (28)

[0218] E 2，re，k-1 =V 2，re，k-1 -I 2，im，k-1 x 2，k-1 (28)

[0219] E 2，im，k-1 =V 2，im，k-1 -I 2，re，k-1 x 2，k-1 (29)

[0220]

[0221]

[0222] Among them, E 2，re，k represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k; E 2，im，k represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k; x 2，k The second Thevenin equivalent parameter of the second system region at time k; E 2，re，k-1 represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k-1; E 2，im，k-1 represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k-1; x2，k-1 V represents the second Thevenin equivalent parameter of the second system region at time k-1; 2，re，k represents the real part of the second voltage mean at time k; V 2，im，k represents the imaginary part of the second voltage mean value at time k; I 2，re，k represents the real part of the sum of the second outflow current at time k; I 2，im，k represents the imaginary part of the sum of the second outflow current at time k; I 2，re，k-1 represents the real part of the sum of the second outflow current at time k-1; I 2，im，k-1 represents the imaginary part of the sum of the second outflow currents at time k-1.

[0223] In an exemplary embodiment of the present invention, the first Thevenin equivalent parameter may include one of the first Thevenin equivalent parameters, and the second Thevenin equivalent parameter may include one of the second Thevenin equivalent parameters;

[0224] The fourth module 840 can use the following formula (32) to determine the power angle difference of the two-machine interconnection system based on the first Thevenin equivalent parameter and the second Thevenin equivalent parameter:

[0225]

[0226] Among them, δ0 represents the power angle difference; E 1,im,k represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k; E 1,re,k represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k; E 2,im,k represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k; E 2,re,k represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k.

[0227] In an exemplary embodiment of the present invention, the fifth module 850 may determine the equivalent system inertia of the two-machine interconnected system based on the transmission power and the power angle difference in the following manner:

[0228] Determine the rated angular speed of the rotor of a multi-machine power system;

[0229] determining a target eigenvalue corresponding to a target oscillation mode;

[0230] Based on the target eigenvalue, rated angular velocity, transmitted power and power angle difference, the equivalent system inertia of the two-machine interconnected system is determined.

[0231] In an exemplary embodiment of the present invention, the sixth module 860 may determine the system inertia of the multi-machine power system based on the equivalent system inertia in the following manner:

[0232] Determine a first right eigenvector mean, wherein the first right eigenvector mean is an average value of right eigenvectors corresponding to each unit in the first system area;

[0233] Determining a second right eigenvector mean, wherein the second right eigenvector mean is an average value of right eigenvectors corresponding to each unit in the second system area;

[0234] determining a first inertia of the first system region and a second inertia of the second system region based on the first right eigenvector mean, the second right eigenvector mean, the target eigenvalue, and the equivalent system inertia;

[0235] The system inertia of the multi-machine power system is determined based on the sum of the first inertia and the second inertia.

[0236] Figure 9 An example of a physical structure diagram of an electronic device is shown below. Figure 9 As shown, the electronic device may include: a processor (processor) 910, a communication interface (Communications Interface) 920, a memory (memory) 930 and a communication bus 940, wherein the processor 910, the communication interface 920, and the memory 930 communicate with each other through the communication bus 940. The processor 910 can call the logic instructions in the memory 930 to execute the power system inertia monitoring method, which is applied to a multi-machine power system. The power system inertia monitoring method includes: performing electromechanical oscillation mode identification on the multi-machine power system to obtain multiple identified oscillation modes; determining a target oscillation mode based on the identified oscillation mode; dividing the multi-machine power system into a first system area and a second system area based on the target oscillation mode, wherein the multi-machine power system is equivalent to a two-machine interconnected system based on the first system area and the second system area; determining the transmission power and power angle difference of the two-machine interconnected system based on the first system area and the second system area; determining the equivalent system inertia of the two-machine interconnected system based on the transmission power and the power angle difference; and determining the system inertia of the multi-machine power system based on the equivalent system inertia.

[0237] In addition, the logic instructions in the above-mentioned memory 930 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0238] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the power system inertia monitoring method provided by the above-mentioned methods. The power system inertia monitoring method is applied to a multi-machine power system. The power system inertia monitoring method includes: identifying electromechanical oscillation modes of the multi-machine power system to obtain multiple identified oscillation modes; determining a target oscillation mode based on the identified oscillation modes; dividing the multi-machine power system into a first system area and a second system area based on the target oscillation mode, wherein the multi-machine power system is equivalent to a two-machine interconnected system based on the first system area and the second system area; determining the transmission power and power angle difference of the two-machine interconnected system based on the first system area and the second system area; determining the equivalent system inertia of the two-machine interconnected system based on the transmission power and the power angle difference; and determining the system inertia of the multi-machine power system based on the equivalent system inertia.

[0239] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, is implemented to execute the power system inertia monitoring method provided by the above-mentioned methods, wherein the power system inertia monitoring method is applied to a multi-machine power system, and the power system inertia monitoring method includes: identifying electromechanical oscillation modes of the multi-machine power system to obtain multiple identified oscillation modes; determining a target oscillation mode based on the identified oscillation modes; dividing the multi-machine power system into a first system area and a second system area based on the target oscillation mode, wherein the multi-machine power system is equivalent to a two-machine interconnected system based on the first system area and the second system area; determining the transmission power and power angle difference of the two-machine interconnected system based on the first system area and the second system area; determining the equivalent system inertia of the two-machine interconnected system based on the transmission power and the power angle difference; and determining the system inertia of the multi-machine power system based on the equivalent system inertia.

[0240] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0241] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

[0242] It should be further understood that, although operations are described in a particular order in the accompanying drawings in the embodiments of the present invention, this should not be construed as requiring that the operations be performed in the particular order shown or in a serial order, or that all of the operations shown be performed to obtain the desired results. In certain circumstances, multitasking and parallel processing may be advantageous.

[0243] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for monitoring inertia of a power system, characterized in that: The power system inertia monitoring method is applied to a multi-machine power system, and the power system inertia monitoring method includes: performing electromechanical oscillation mode identification on the multi-machine power system to obtain a plurality of identified oscillation modes; determining a target oscillation pattern based on the identified oscillation pattern; Based on the target oscillation mode, the multi-machine power system is divided into a first system area and a second system area, wherein the multi-machine power system is equivalent to a two-machine interconnected system based on the first system area and the second system area; Determining, based on the first system area and the second system area, a transmission power and a power angle difference of the two-machine interconnection system; determining an equivalent system inertia of the two-machine interconnection system based on the transmission power and the power angle difference; Determining the system inertia of the multi-machine power system based on the equivalent system inertia, wherein determining the transmission power of the two-machine interconnected system based on the first system area and the second system area specifically includes: Determining an inter-region tie line bus based on the first system area and the second system area; Based on the inter-regional tie line bus, determining the inter-regional tie line corresponding to the inter-regional tie line bus; The transmission power of the two-machine interconnection system is determined based on the sum of the transmission powers on all the inter-regional tie lines, wherein: The inter-regional tie lines include a first inter-regional tie line in the first system area and a second inter-regional tie line in the second system area; the inter-regional tie line busbars include a first inter-regional tie line busbar in the first system area and a second inter-regional tie line busbar in the second system area; The determining, based on the first system area and the second system area, a power angle difference of the two-machine interconnected system specifically includes: When the number of units in the first system area is less than the number of units in the second system area, the outlet busbars of the units in the first system area are used as the first inter-area tie line busbars; Determining the second inter-regional tie line bus based on the first inter-regional tie line bus; Determining the first inter-regional tie line based on the first inter-regional tie line bus; Determining the second inter-regional tie line based on the second inter-regional tie line bus; respectively determining a first voltage average of the first inter-region tie line busbar in the first system area at a current moment and a previous moment, and a second voltage average of the second inter-region tie line busbar in the second system area at a current moment and a previous moment; respectively determining a sum of a first outflow current of the first inter-region tie line of the first system area at a current moment and a previous moment, and a sum of a second outflow current of the second inter-region tie line of the second system area at a current moment and a previous moment; determining a first Thevenin equivalent parameter of the first system area based on the sum of the first voltage average and the first outflow current; determining a second Thevenin equivalent parameter of the second system area based on the sum of the second voltage average and the second outflow current; Based on the first Thevenin equivalent parameter and the second Thevenin equivalent parameter, a power angle difference of the two-machine interconnection system is determined.

2. The power system inertia monitoring method according to claim 1, characterized in that: The determining of a target oscillation mode based on the identified oscillation mode specifically includes: Based on a clustering algorithm, clustering values ​​of the identified oscillation patterns are calculated respectively, and the identified oscillation pattern corresponding to the maximum clustering value is determined as the target oscillation pattern.

3. The power system inertia monitoring method according to claim 1, characterized in that: The first Thevenin equivalent parameter includes one of the first Thevenin equivalent parameters and a second of the first Thevenin equivalent parameters; The determining of the first Thevenin equivalent parameter of the first system region based on the sum of the first voltage average and the first outflow current is implemented by using the following formula: E 1,re,k =V 1,re,k -I 1,im,k x 1,k ; E 1,im,k =V 1,im,k -I 1,re,k x 1,k ; E 1,re,k-1 =V 1,re,k-1 -I 1,im,k-1 x 1,k-1 ; E 1,im,k-1 =V 1,im,k-1 -I 1,re,k-1 x 1,k-1 ; Among them, E 1,re,k represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k; E 1,im,k represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k; x 1,k represents the second first Thevenin equivalent parameter of the first system region at time k; E 1,re,k-1 represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k-1; E 1,im,k-1 represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k-1; x 1,k-1 represents the second first Thevenin equivalent parameter of the first system region at time k-1; V 1,re,k represents the real part of the first voltage mean value at time k; V 1,im,k represents the imaginary part of the first voltage mean value at time k; I 1,re,k represents the real part of the sum of the first outflow currents at time k; I 1,im,k represents the imaginary part of the sum of the first outflow currents at time k; I 1,re,k-1 represents the real part of the sum of the first outflow currents at time k-1; I 1,im,k-1 represents the imaginary part of the sum of the first outflow currents at time k-1.

4. The power system inertia monitoring method according to claim 1, characterized in that: The second Thevenin equivalent parameter includes one of the second Thevenin equivalent parameters and two of the second Thevenin equivalent parameters; The second Thevenin equivalent parameter of the second system region is determined based on the sum of the second voltage average value and the second outflow current, and is implemented by using the following formula: E 2,re,k =V 2,re,k -I 2,im,k x 2,k ; E 2,im,k =V 2,im,k -I 2,re,k x 2,k ; E 2,re,k-1 =V 2,re,k-1 -I 2,im,k-1 x 2,k-1 ; E 2,im,k-1 =V 2,im,k-1 -I 2,re,k-1 x 2,k-1 ; Among them, E 2,re,k represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k; E 2,im,k represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k; x 2,k represents the second Thevenin equivalent parameter 2 of the second system region at time k; E 2,re,k-1 represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k-1; E 2,im,k-1 represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k-1; x 2,k-1 V represents the second Thevenin equivalent parameter of the second system region at time k-1; 2,re,k represents the real part of the second voltage mean value at time k; V 2,im,k represents the imaginary part of the second voltage mean value at time k; I 2,re,k represents the real part of the sum of the second outflow currents at time k; I 2,im,k represents the imaginary part of the sum of the second outflow currents at time k; I 2,re,k-1 represents the real part of the sum of the second outflow currents at time k-1; I 2,im,k-1 represents the imaginary part of the sum of the second outflow currents at time k-1.

5. The power system inertia monitoring method according to claim 1, characterized in that: The first Thevenin equivalent parameter includes one of the first Thevenin equivalent parameters, and the second Thevenin equivalent parameter includes one of the second Thevenin equivalent parameters; The power angle difference of the two-machine interconnection system is determined based on the first Thevenin equivalent parameter and the second Thevenin equivalent parameter, and is implemented by using the following formula: Wherein, δ0 represents the power angle difference; E 1,im,k represents the imaginary part of one of the first Thevenin equivalent parameters of the first system region at time k; E 1,re,k represents the real part of one of the first Thevenin equivalent parameters of the first system region at time k; E 2,im,k represents the imaginary part of one of the second Thevenin equivalent parameters of the second system region at time k; E 2,re,k represents the real part of one of the second Thevenin equivalent parameters of the second system region at time k.

6. The method for monitoring inertia of a power system according to claim 1, wherein: The determining, based on the transmission power and the power angle difference, the equivalent system inertia of the two-machine interconnection system specifically includes: determining a rated angular speed of a rotor of the multi-machine power system; determining a target eigenvalue corresponding to the target oscillation mode; An equivalent system inertia of the two-machine interconnection system is determined based on the target characteristic value, the rated angular velocity, the transmission power, and the power angle difference.

7. The method for monitoring inertia of a power system according to claim 6, wherein: Determining the system inertia of the multi-machine power system based on the equivalent system inertia specifically includes: Determine a first right eigenvector mean, wherein the first right eigenvector mean is an average value of right eigenvectors corresponding to each unit in the first system area; Determine a second right eigenvector mean, wherein the second right eigenvector mean is an average value of right eigenvectors corresponding to each unit in the second system area; determining a first inertia of the first system region and a second inertia of the second system region based on the first right eigenvector mean, the second right eigenvector mean, the target eigenvalue, and the equivalent system inertia; A system inertia of the multi-machine power system is determined based on the sum of the first inertia and the second inertia.

8. A power system inertia monitoring device, characterized in that: The power system inertia monitoring device is applied to a multi-machine power system, and is used to implement the power system inertia monitoring method according to any one of claims 1 to 7, and the device includes: The first module is configured to identify an electromechanical oscillation mode of the multi-machine power system to obtain a plurality of identified oscillation modes; A second module is configured to determine a target oscillation pattern based on the identified oscillation pattern; a third module, configured to divide the multi-machine power system into a first system area and a second system area based on the target oscillation mode, wherein the multi-machine power system is equivalent to a two-machine interconnected system based on the first system area and the second system area; A fourth module is configured to determine a transmission power and a power angle difference of the two-machine interconnection system based on the first system area and the second system area; A fifth module is configured to determine an equivalent system inertia of the two-machine interconnection system based on the transmission power and the power angle difference; A sixth module is configured to determine the system inertia of the multi-machine power system based on the equivalent system inertia.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the power system inertia monitoring method according to any one of claims 1 to 7 is implemented.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the power system inertia monitoring method according to any one of claims 1 to 7 is implemented.

11. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the power system inertia monitoring method according to any one of claims 1 to 7 is implemented.

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