Method for monitoring power oscillation of alternating current network caused by detuning of multi-voltage-source controlled unit

Abstract

The invention discloses a monitoring method for alternating current network power oscillation caused by detuning of a multi-voltage source type controlled unit, and belongs to the field of power oscillation suppression of a power system. The suppression method comprises the following steps: S1, calculating cross-section power flow characteristic variation degree information of a weak control type node or a voltage source type controlled unit grid connection point; s2, judging whether detuning type oscillation event alarm information is sent or not, and if not, returning to S1; if the alarm is given, entering S3; s3, judging a detuning type; s4, aiming at different detuning types, implementing detuning type power oscillation suppression measures; s5, judging whether the detuning disappears or not, if so, releasing the alarm and returning to S1; otherwise, entering S6; s6, coordinating the two-end or single-end voltage source type controlled unit of which the line power flow still exceeds the threshold value to perform phase compensation or power compensation control; s7, judging whether the detuning disappears or not, if so, releasing the alarm and returning to S1; otherwise, entering S8; and S8, for the voltage source type controlled unit which cannot meet the detuning suppression instruction requirement, the voltage source type controlled unit temporarily quits the fixed-frequency output mode.

Description

Technical Field

[0001] The present invention belongs to the field of power oscillation suppression in power systems, and particularly relates to a monitoring method for power oscillation in an AC network caused by the detuning of multi-voltage-source controlled units. Background Art

[0002] Grid-forming (GFM) converters have the advantages of providing voltage support and frequency support for the power grid, and will become important components required for new energy power sources, energy storage, etc. to access the new power system. The GFM converters at the ports make the output characteristics of new energy and energy storage devices exhibit the characteristics of a controlled voltage source. According to this feature, such units can be collectively referred to as voltage source controlled units (VSCUs). The access of VSCUs to the new power system will cause new stability problems in the following two aspects.

[0003] On the one hand, some traditional synchronous motors are gradually replaced by new energy power sources, and the large-scale access of power electronic devices weakens the inertia of the power grid and reduces the phase synchronization ability of the power grid. On the other hand, there are differences in the GFM control accuracy and frequency measurement accuracy of VSCUs at different nodes. Under the distributed GFM mode, VSCUs lack a frequency synchronization mechanism, and the frequency synchronization ability of VSCUs is weak. Under the action of weak phase synchronization ability and weak frequency synchronization ability, it is easy to occur the detuning phenomenon that the output frequencies of multiple VSCUs are inconsistent for a long time under steady-state conditions. This detuning phenomenon is externally manifested as a long-period detuning oscillation on the AC line, and this detuning oscillation threatens the safe and stable operation of the power grid.

[0004] Therefore, a monitoring method for power oscillation in an AC network caused by the detuning of multi-voltage-source controlled units is proposed. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a monitoring method for power oscillation in an AC network caused by the detuning of multi-voltage-source controlled units, and solve the problems in the prior art.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A monitoring method for power oscillation in an AC network caused by the detuning of multi-voltage-source controlled units, comprising the following steps:

[0008] S1, collecting information of voltage source controlled units, and calculating the information of the degree of change in the power flow characteristics of the section at the connection point of the weakly controlled node or the voltage source controlled unit;

[0009] S2, based on the information of the degree of change in the power flow characteristics, determining whether to issue an alarm message for a detuning oscillation event. If not, return to S1; if alarmed, enter S3;

[0010] S3, judging the detuning type based on the electrical connection relationship between the detuned voltage source type controlled unit, the weak control type node with abnormal power flow characteristics and the AC line;

[0011] S4, implement detuned power oscillation suppression measures for different detuning types;

[0012] S5, determine whether the detuning has disappeared. If so, clear the alarm and return to S1; if not, enter S6;

[0013] S6, coordinate the two-end or single-end voltage source type controlled units whose line power flow still exceeds the threshold value to perform phase compensation or power compensation control;

[0014] S7, determine whether the detuning has disappeared. If so, clear the alarm and return to S1; if not, enter S8;

[0015] S8, for the voltage source type controlled unit that cannot meet the detuning suppression instruction requirements, let it temporarily exit the fixed frequency output mode.

[0016] Furthermore, the calculation formula of the tidal current characteristic abnormality degree information is:

[0017]

[0018] In the formula, κ swe-p is the index of power variation degree of equivalent load at weak control node, K ppl P is the index of the abnormal change degree of active power of line l; Lmax is the maximum active power of the load at the weak control node; is the load active power under the corresponding harmonic working condition; P lmax is the maximum active power of line l; P l [har] is the active power of line l in the same harmonic condition.

[0019] Furthermore, the conditions for determining whether to issue a detuned oscillation event alarm are:

[0020] When the equivalent load power at the weak control node satisfies: Or the output power of any voltage source controlled unit satisfies: When the detuning type oscillation event alarm information is issued; otherwise, no detuning type oscillation event alarm information is issued; where P L (t) is the equivalent load power at the weak control node,

[0021] P l (t) is the active power of line l, and Threshold values set respectively for the equivalent load power variation degree at the weakly controlled node and the active power variation degree of line l.

[0022] Furthermore, the steps for judging the detuning type are as follows:

[0023] S401. After the power grid topology transformation, if a system is formed where two voltage-source controlled units are connected by an equivalent branch impedance, the detuning problem of the two voltage-source controlled units in this system belongs to the double voltage-source controlled unit detuning type;

[0024] S402. After the power grid topology transformation, if a star system is formed where multiple voltage-source controlled units are connected to a weakly controlled node through multiple equivalent branch impedances, the detuning problem of the multiple voltage-source controlled units in this system belongs to the multi-voltage-source controlled unit detuning type.

[0025] Furthermore, the condition for judging whether the detuning disappears is as follows:

[0026] When the output powers of all voltage-source controlled units satisfy: it is judged that the detuning disappears; otherwise, the detuning problem is not solved; where, is the average output power of the i-th voltage-source controlled unit; P i-up and P i-low are respectively the upper and lower limits of the average output power of the i-th voltage-source controlled unit set.

[0027] Furthermore, the phase compensation control is: adjusting the output voltage phase of the voltage-source controlled unit according to the power grid control requirements;

[0028] The power compensation control is: adjusting the output power of the voltage-source controlled unit according to the power grid control requirements;

[0029] A monitoring system for power oscillation in an AC network caused by detuning of multi-voltage-source controlled units includes:

[0030] Detuning type power oscillation monitoring module: collecting information of voltage-source controlled units;

[0031] Variation degree calculation module: calculating the variation degree information of the section power flow characteristics of the weakly controlled node or the connection point of the voltage-source controlled unit;

[0032] Detuning type power oscillation alarm module: based on the variation degree information of the power flow characteristics, judging whether to send an alarm message for the detuning type oscillation event. If not alarmed, it returns to the detuning type power oscillation monitoring module; if alarmed, it enters the detuning type judgment module;

[0033] Detuning type judgment module: based on the electrical connection relationship between the detuned voltage-source controlled units, the weakly controlled nodes with power flow characteristic variation, and the AC lines, judging the detuning type;

[0034] Oscillation suppression module: implements detuned power oscillation suppression measures for different detuning types;

[0035] Detuning disappearance first judgment module: judge whether the detuning disappears. If so, cancel the alarm and return to the detuning power oscillation monitoring module; if not, enter the compensation control module;

[0036] Compensation control module: coordinates the two-end or single-end voltage source controlled units whose line power flow still exceeds the threshold value to jointly perform phase compensation or power compensation control;

[0037] Detuning disappearance second judgment module: judge whether the detuning disappears. If so, cancel the alarm and return to the detuning power oscillation monitoring module; if not, enter the mode exit module;

[0038] And, the mode exit module: for the voltage source type controlled unit that cannot meet the detuning suppression instruction requirements, let it temporarily exit the fixed frequency output mode.

[0039] A computer storage medium stores a readable program, which can execute the above-mentioned method for monitoring AC network power oscillation caused by detuning of multiple voltage source type controlled units when the program is running.

[0040] An electronic device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus;

[0041] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the above-mentioned monitoring method for AC network power oscillation caused by detuning of multiple voltage source type controlled units.

[0042] A computer program product includes computer instructions, wherein the computer instructions instruct a computing device to execute operations corresponding to the above-mentioned method for monitoring power oscillation of an AC network caused by detuning of a multi-voltage source type controlled unit.

[0043] Beneficial effects of the present invention:

[0044] For a detuned AC network with multiple voltage source controlled units, the present invention can monitor and eliminate the detuned power oscillation problem occurring in the network, filling the gap in the research on detuned oscillation monitoring of multiple VSCUs, and is beneficial to the safe and stable operation of voltage source controlled units and power grids. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0046] Figure 1 is the flowchart of the monitoring method for power oscillation of the AC network caused by the detuning of the multi-voltage-source controlled unit;

[0047] Figure 2 is the structural schematic diagram of the present invention, the equivalent model diagram of the detuned network of the multi-voltage-source controlled unit. Specific embodiments

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0049] Embodiment 1

[0050] The monitoring method for power oscillation of the AC network caused by the detuning of the multi-voltage-source controlled unit includes the following steps:

[0051] S1. Collect information of the voltage-source controlled unit and calculate the degree of variation information of the cross-section power flow characteristics of the weakly controlled node or the connection point of the voltage-source controlled unit.

[0052] Calculate the degree of variation information of the load power flow and the line power flow at the weakly controlled node according to formulas (1) and (2) respectively.

[0053]

[0054] In the formula: κ swe-p is the index of the degree of variation of the equivalent load power at the weakly controlled node, K ppl is the index of the degree of variation of the active power of line l; P Lmax is the maximum value of the load active power at the weakly controlled node; is the load active power under the corresponding same-harmonic condition; P lmax is the maximum value of the active power of line l; P l [har] is the active power of line l under the same-harmonic condition.

[0055] S2. Based on the information of the degree of variation of power flow characteristics, determine whether to send an alarm message for the out-of-resonance oscillation event. When the equivalent load power at the weakly controlled node satisfies Equation (3) or the output power of any voltage source type controlled unit satisfies Equation (4), send an alarm message for the out-of-resonance oscillation event and execute S3. Otherwise, do not send an alarm message for the out-of-resonance oscillation event and return to S1.

[0056]

[0057] In the formula, P L (t) is the equivalent load power at the weakly controlled node, and P l (t) is the active power of line l. and are the threshold values set for the degree of variation of the equivalent load power at the weakly controlled node and the degree of variation of the active power of line l, respectively.

[0058] S3. Based on the electrical connection relationship between the out-of-resonance voltage source type controlled unit, the weakly controlled node with power flow characteristic variation, and the AC line, determine the out-of-resonance type;

[0059] The steps to determine the out-of-resonance type are as follows:

[0060] S301. After the power grid topology transformation, if a system is formed where two voltage source type controlled units are connected by an equivalent branch impedance, the out-of-resonance problem of the two voltage source type controlled units in this system belongs to the double voltage source type controlled unit out-of-resonance type.

[0061] S302. After the power grid topology transformation, if a star system is formed where multiple voltage source type controlled units are connected to a weakly controlled node through multiple equivalent branch impedances, the out-of-resonance problem of the multiple voltage source type controlled units in this system belongs to the multi-voltage source type controlled unit out-of-resonance type.

[0062] S4. For different out-of-resonance types, implement out-of-resonance power oscillation suppression measures;

[0063] The steps to implement out-of-resonance power oscillation suppression measures include:

[0064] S401. If only the multi-voltage source type controlled unit is out of resonance, according to the requirements of the power grid, the multi-voltage source type controlled unit adjusts its output frequency;

[0065] S402. If only the double voltage source type controlled unit is out of resonance, according to the requirements of the power grid, the two voltage source type controlled units adjust their output frequencies;

[0066] S403. If both the double voltage source type controlled unit and the multi-voltage source type controlled unit are out of resonance, but there is no direct electrical connection between the former system and the latter system, then according to the requirements of the power grid, execute the control instructions for adjusting the output frequency respectively;

[0067] S404, if detuning of the dual voltage source type controlled units and detuning of the multi-voltage source type controlled units occur simultaneously, and there is a direct electrical connection between the former system and the different voltage source type controlled units in the latter system, then according to the requirements of the power grid, the output frequencies of the different multi-voltage source type controlled units in the two systems need to be adjusted simultaneously.

[0068] S5, determine whether the detuning disappears. If so, cancel the alarm and return to S1 to continue. If not, it means that the detuning factor has not been completely eliminated or the detuning index has not been reduced to below the threshold value, indicating that there is still a certain residual control amount, and it is necessary to continue to execute S6;

[0069] The condition for judging whether the detuning disappears is: when the output power of all voltage source controlled units satisfies equation (5), the detuning disappears. Otherwise, the detuning problem is not solved.

[0070]

[0071] Where P i (t) is the average output power of the ith voltage source controlled unit; P i-up , P i-low are the upper and lower limits of the mean output power of the i-th voltage source controlled unit.

[0072] S6, coordinating the two-end or single-end voltage source type controlled units whose line power flow still exceeds the threshold value to jointly perform phase compensation or power compensation control;

[0073] Phase compensation control is to adjust the output voltage phase of the voltage source type controlled unit according to the system control requirements.

[0074] Power compensation control is: adjusting the output power of the voltage source type controlled unit according to the control requirements.

[0075] S7, determine whether the detuning has disappeared. If so, cancel the alarm and return to S1; if not, execute S8;

[0076] The condition for judging whether the detuning disappears is: when the output power of all voltage source controlled units satisfies equation (5), the detuning disappears. Otherwise, the detuning problem is not solved.

[0077] S8: For voltage source controlled units that cannot meet the requirements of the detuning suppression command, they are allowed to temporarily exit the fixed frequency output mode, but it is necessary to ensure that they can still accurately control the voltage amplitude and initial phase, or active / reactive power.

[0078] Based on similar inventive concepts, an embodiment of the present invention further provides a computer storage medium storing a readable program, which, when executed, can execute the above-mentioned method for monitoring AC network power oscillation caused by detuning of multiple voltage source type controlled units.

[0079] Based on similar inventive concepts, an embodiment of the present invention provides an electronic device, comprising: a processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other through the communication bus;

[0080] The memory is used to store at least one executable instruction, and the executable instruction enables the processor to execute operations corresponding to the above-mentioned monitoring method for AC network power oscillation caused by detuning of multiple voltage source type controlled units.

[0081] Based on similar inventive concepts, an embodiment of the present invention further provides a computer program product, including computer instructions, which instruct a computing device to execute operations corresponding to the above-mentioned method for monitoring AC network power oscillation caused by detuning of multiple voltage source type controlled units.

[0082] Example 2

[0083] Based on the monitoring method for AC network power oscillation caused by detuning of multiple voltage source type controlled units proposed in Example 1, this embodiment proposes a monitoring system for AC network power oscillation caused by detuning of multiple voltage source type controlled units, including:

[0084] Detuned power oscillation monitoring module: collects information of voltage source controlled units;

[0085] Abnormal variation degree calculation module: calculates abnormal variation degree information of power flow characteristics of the section of the grid connection point of the weak control node or voltage source controlled unit;

[0086] Detuned power oscillation alarm module: Based on the abnormal degree of power flow characteristics, it determines whether to issue a detuned oscillation event alarm. If no alarm is issued, it returns to the detuned power oscillation monitoring module; if an alarm is issued, it enters the detuned type judgment module;

[0087] Detuning type judgment module: Detuning type is judged based on the electrical connection relationship between the detuned voltage source controlled unit, the weak control node with abnormal power flow characteristics and the AC line;

[0088] Oscillation suppression module: implements detuned power oscillation suppression measures for different detuning types;

[0089] Detuning disappearance first judgment module: judge whether the detuning disappears. If so, cancel the alarm and return to the detuning power oscillation monitoring module; if not, enter the compensation control module;

[0090] Compensation control module: coordinate the two ends of the line where the power flow still exceeds the threshold value or the voltage source type controlled units at both ends to jointly perform phase compensation or power compensation control;

[0091] Detuning disappearance second judgment module: judge whether the detuning disappears. If so, cancel the alarm and return to the detuning power oscillation monitoring module; if not, enter the mode exit module;

[0092] And, the mode exit module: for the voltage source type controlled unit that cannot meet the detuning suppression instruction requirements, let it temporarily exit the fixed frequency output mode.

[0093] Example 3

[0094] In this embodiment, the effect of the monitoring method of the AC network power oscillation caused by detuning of multiple voltage source type controlled units of the present invention is verified through simulation.

[0095] like Figure 2 As shown, the detuned network equivalent model of the multi-voltage source controlled unit is taken as the basic model, the three-phase line voltage reference value is selected as 500kV, and n=5 is set.

[0096] The simulation system was detuned at 0s, and the five VSCU output frequencies f1, f2, f3, f4, and f5 were 50.005Hz, 50.004Hz, 50.003Hz, 50.002Hz, and 49.999Hz, respectively. At around 21.6s, it was detected that the power drop exceeded the threshold value, and at around 1.5s, around 1.6s, around 21.4s, around 1s, and around 0.1s, the power signals of lines 1-0, 2-0, 3-0, 4-0, and 5-0 exceeded the threshold value. At around 0.1s, adjustments were made according to the method described in the present invention. The changes in characteristic indicators before and after the adjustment are shown in Table 1. The power characteristic indicators of the equivalent weak-controlled load node 0 and the line power characteristic indicators are restored to the level of the same harmonic condition.

[0097] Table 1 Changes in characteristic indicators before and after adjustment

[0098]

[0099] It can be seen from Table 1 that the method of the present invention can suppress detuned power oscillation and ensure the safety of power grid operation.

[0100] The method of the present invention can be implemented in hardware, firmware, or be implemented as software or computer code that can be stored in a recording medium (such as a CDROM, RAM, floppy disk, hard disk, or magneto-optical disk), or be implemented as computer code originally stored in a remote recording medium or a non-transitory machine-readable medium and to be downloaded through a network and stored in a local recording medium, so that the method described herein can be stored on such a software process on a recording medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware (such as an ASIC or FPGA). It can be understood that a computer, a processor, a microprocessor controller, or programmable hardware includes a storage component (such as a RAM, ROM, flash memory, etc.) that can store or receive software or computer code, and when the software or computer code is accessed and executed by the computer, the processor, or the hardware, the method described herein is implemented. In addition, when a general-purpose computer accesses the code for implementing the method shown herein, the execution of the code converts the general-purpose computer into a dedicated computer for executing the method shown herein.

[0101] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and what is described in the above embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A monitoring method for power oscillation of an AC network caused by detuning of a multi-voltage-source type controlled unit, characterized in that, The following steps are involved: S1, collect information of voltage source controlled units, calculate the abnormal degree of power flow characteristics of weak control nodes or voltage source controlled units connected to the grid; S2, based on the information on the degree of abnormal change of the power flow characteristics, determine whether to issue a detuning oscillation event alarm. If no alarm is issued, return to S1; if an alarm is issued, enter S3; S3, judging the detuning type based on the electrical connection relationship between the detuned voltage source type controlled unit, the weak control type node with abnormal power flow characteristics and the AC line; S4, implement detuned power oscillation suppression measures for different detuning types; S5, determine whether the detuning has disappeared. If so, clear the alarm and return to S1; if not, enter S6; S6, coordinate the two-end or single-end voltage source type controlled units whose line power flow still exceeds the threshold value to perform phase compensation or power compensation control; S7, determine whether the detuning disappears, if so, cancel the alarm and return to S1; If it does not disappear, go to S8; S8, for the voltage source type controlled unit that cannot meet the detuning suppression instruction requirements, let it temporarily exit the fixed frequency output mode.

2. The monitoring method for power oscillation of an AC network caused by detuning of a multi-voltage-source type controlled unit according to claim 1, characterized in that, The calculation formula of the abnormal change degree information of the tidal current characteristics is: where κ swe-p is the equivalent load power variation degree index at the weakly controlled node, and K ppl is the active power variation degree index of line l; P Lmax is the maximum active power of the load at the weakly controlled node; is the active power of the load under the corresponding harmonic condition; P lmax is the maximum active power of line l; is the active power of line l under the harmonic condition.

3. The monitoring method for power oscillation of an AC network caused by detuning of a multi-voltage-source type controlled unit according to claim 1, wherein The conditions for issuing a detuning oscillation event alarm are: When the equivalent load power at the weakly controlled node satisfies: Or when the output power of any voltage source type controlled unit satisfies: An alarm message for the detuned oscillation event is sent. Otherwise, no detuning oscillation event warning information is issued; where P L (t) is the equivalent load power at the weakly controlled node, P l (t) is the active power of line l, and are the threshold values set for the degree of change in the equivalent load power at the weakly controlled node and the degree of change in the active power of line l, respectively.

4. The monitoring method for power oscillation of an AC network caused by detuning of a multi-voltage-source type controlled unit according to claim 1, characterized in that The steps to determine the detuning type are: S401, after the grid topology is transformed, if a system is formed in which two voltage source type controlled units are connected via equivalent branch impedances, then the detuning problem of the two voltage source type controlled units in the system belongs to the detuning type of dual voltage source type controlled units; S402, after the grid topology transformation, if a star system is formed in which multiple voltage source type controlled units are connected to weak control type nodes via multiple equivalent branch impedances, then the detuning problem of multiple voltage source type controlled units in the system belongs to the detuning type of multiple voltage source type controlled units.

5. The monitoring method for power oscillation of an AC network caused by detuning of a multi-voltage-source type controlled unit according to claim 1, characterized in that, The condition for judging whether the detuning disappears is: When the output powers of all voltage-source controlled units satisfy: it is determined that the detuning disappears; otherwise, the detuning problem remains unsolved. Among them, is the average output power of the i-th voltage-source controlled unit; P i-up , P i-low are respectively the upper and lower limits of the average output power of the i-th voltage-source controlled unit set.

6. The monitoring method for power oscillation of an AC network caused by detuning of a multi-voltage-source type controlled unit according to claim 1, wherein The phase compensation control is: adjusting the output voltage phase of the voltage source type controlled unit according to the grid control requirements; The power compensation control is to adjust the output power of the voltage source type controlled unit according to the power grid control requirements.

7. Monitoring system for power oscillation of AC network caused by detuning of multi-voltage-source controlled unit, characterized in that include: Detuned power oscillation monitoring module: collects information of voltage source controlled units; Abnormal variation degree calculation module: calculates abnormal variation degree information of power flow characteristics of the section of the grid connection point of the weak control node or voltage source controlled unit; Detuned power oscillation alarm module: Based on the abnormal degree of power flow characteristics, it determines whether to issue a detuned oscillation event alarm. If no alarm is issued, it returns to the detuned power oscillation monitoring module; if an alarm is issued, it enters the detuned type judgment module; Detuning type judgment module: Detuning type is judged based on the electrical connection relationship between the detuned voltage source controlled unit, the weak control node with abnormal power flow characteristics and the AC line; Oscillation suppression module: implements detuned power oscillation suppression measures for different detuning types; Detuning disappearance first judgment module: judge whether the detuning disappears. If so, cancel the alarm and return to the detuning power oscillation monitoring module; If it does not disappear, then enter the compensation control module; Compensation control module: coordinates the two-end or single-end voltage source controlled units whose line power flow still exceeds the threshold value to jointly perform phase compensation or power compensation control; Detuning disappearance second judgment module: judges whether the detuning disappears. If so, the alarm is cleared and returns to the detuning power oscillation monitoring module; If it does not disappear, enter the mode exit module; And, the mode exit module: for the voltage source type controlled unit that cannot meet the detuning suppression instruction requirements, let it temporarily exit the fixed frequency output mode.

8. A computer storage medium stores a readable program, characterized in that, When the program is running, the method for monitoring AC network power oscillation caused by detuning of multiple voltage source type controlled units as described in any one of claims 1 to 6 can be executed.

9. An electronic device, characterized in that, include: A processor, a memory, a communication interface and a communication bus, wherein the processor, the memory and the communication interface communicate with each other via the communication bus; The memory is used to store at least one executable instruction, and the executable instruction enables the processor to perform operations corresponding to the method for monitoring AC network power oscillation caused by detuning of a multi-voltage source type controlled unit according to any one of claims 1-6.

10. A computer program product comprising computer instructions, characterized in that, The computer instructions instruct the computing device to execute operations corresponding to the method for monitoring AC network power oscillation caused by detuning of multiple voltage source type controlled units as described in any one of claims 1-6.

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