A method, device, terminal equipment and storage medium for evaluating transient stability of power system based on phase area

Abstract

The present invention discloses a method, apparatus, terminal device, and storage medium for evaluating transient stability of a power system based on phase area. The method comprises: first initializing a standard phasor area diagram of the power system, a fault-clearing data set, a fault-free data set, and a system-recovery data set; then obtaining the voltage phasors of the phasor measurement units until the voltage phasors at two adjacent moments converge, and obtaining the first voltage parameters of the phasor measurement units during the fault-clearing period; updating each data set based on the initialized data sets and all first voltage parameters; then calculating the absolute value of the difference between the system phase area at the current moment and the system phase area at the previous moment based on each updated data set; and when the absolute value is not greater than a preset second convergence threshold, determining whether the power system has recovered transient stability based on the sampling frequency, sampling time, and the number of sampling times of the generator. By implementing the present invention, the accuracy of the transient stability evaluation results of the power system can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power system stability assessment, and in particular to a method, device, equipment and storage medium for evaluating power system transient stability based on phase area. Background Art

[0002] Currently, the increased use of converter-based resources due to the expansion of renewable energy is leading to dynamic grid instability, weakening the system's inertial response, which in turn reduces the overall transient stability margin of the power system and makes it more susceptible to transient instability due to system faults. This can lead to decreased productivity, equipment damage, increased emergency response costs, and even significant financial impacts.

[0003] Most existing technologies use the rotor angle measured synchronously by a phasor measurement unit to assess transient stability. The rotor angle assessment requires linear estimation by constructing a swing equation based on the measured current and voltage at the generator terminal. However, during transient response, the power system may become unstable in a single generator after being subjected to a large disturbance, resulting in incorrect calculation of the rotor angle, which in turn reduces the accuracy of the transient stability assessment results of the power system. Summary of the Invention

[0004] The present invention provides a method, device, terminal equipment and storage medium for evaluating transient stability of an electric power system based on phase area, which can improve the accuracy of transient stability evaluation results of an electric power system.

[0005] An embodiment of the present invention provides a method for evaluating transient stability of a power system based on phase area, comprising:

[0006] Initializing the phasor area standard diagram of the power system, and obtaining an initialized fault clearing data set, a fault-free data set, and a system recovery data set based on the initialized phasor area standard diagram; wherein the initialized data sets are all 0;

[0007] Acquire a voltage phasor of a phasor measurement unit in the power system in real time, until the difference between the absolute value of the voltage phasor at the previous moment and the absolute value of the voltage phasor at the current moment is greater than a preset first convergence threshold, clear the fault in the power system, and acquire a first voltage parameter of the phasor measurement unit at a moment before the fault is cleared, a moment when the fault is cleared, and each moment between the moment before the fault is cleared and the moment when the fault is cleared: wherein the first voltage parameter includes: a first voltage phasor, and a first voltage phase angle corresponding to the first voltage phasor;

[0008] Calculating an updated fault-clearing dataset, an updated fault-free dataset, and an updated system-recovery dataset based on the initialized fault-clearing dataset, the initialized fault-free dataset, the initialized system-recovery dataset, and the first voltage phasors and first voltage phase angles at all times;

[0009] Calculating a system phase area based on the updated fault-cleared data set, the updated fault-free data set, and the updated system recovery data set; determining whether the power system can be restored to stability based on the system phase area; and calculating an absolute value of a difference between the system phase area at a current moment and the system phase area at a previous moment if the power system can be restored to stability;

[0010] When the absolute value is not greater than a preset second convergence threshold, the sampling frequency and sampling time of the phasor measurement unit are obtained, and it is determined whether the power system has restored transient stability based on the sampling frequency, sampling time and the number of sampling times of the generator.

[0011] Furthermore, the above calculation of the updated fault-clearing dataset, the updated fault-free dataset, and the updated system recovery dataset based on the initialized fault-clearing dataset, the initialized fault-free dataset, the initialized system recovery dataset, and the first voltage phasor and the first voltage phase angle at all times includes:

[0012] Repeat the fault clearing judgment operation until the difference between the absolute value of the first voltage phasor at the next moment and the absolute value of the first voltage phasor at the current moment is greater than a preset third convergence threshold;

[0013] updating the current first fault-clearing dataset, the current first fault-free dataset, and the initialized system recovery dataset according to the current voltage phasor corresponding to the current fault-clearing completion moment, to obtain the updated fault-clearing dataset, the updated fault-free dataset, and the updated system recovery dataset;

[0014] The above-mentioned fault clearing judgment operation includes:

[0015] After the current fault is cleared, obtaining a current second voltage parameter of the phasor measurement unit at the current fault clearing completion moment and at each moment between the current fault clearing completion moment and the first fault clearing completion moment; wherein the current second voltage parameter includes: a current second voltage phasor and a current second voltage phase angle, and an initial second voltage parameter is 0;

[0016] Calculating a phase area of ​​a current fault-clearing interval according to a current first fault-clearing data set, a current first fault-free data set, a current second voltage phasor, and the first voltage phasor;

[0017] Calculating a fault phase area limit range based on the first voltage phase angle corresponding to the moment before the fault is cleared in the first voltage phase angle, and obtaining the first voltage phasor of the phasor measurement unit at the current moment and the next moment when the phase area of ​​the current fault clearing interval is within the fault phase area limit range;

[0018] If the difference between the absolute value of the first voltage phasor at the next moment and the absolute value of the first voltage phasor at the current moment is not greater than the preset third convergence threshold, the fault of the power system is cleared again.

[0019] Furthermore, the calculation of the current fault-clearing interval phase area based on the current first fault-clearing data set, the current first fault-free data set, the current second voltage phasor, and the first voltage phasor includes:

[0020] Calculating a union of a current first fault-clearing data set, the first voltage phasor, and the current second voltage phasor to obtain a current updated first fault-clearing data set; wherein the initial first fault-clearing data set is the initialized fault-clearing data set;

[0021] Calculating the union of the current first fault-free data set, the first voltage phasor, and the current second voltage phasor to obtain the current updated first fault-free data set; wherein the initial first fault-free data set is the initialized fault-free data set;

[0022] The phase area of ​​the current fault-clearing interval is calculated based on the currently updated first fault-clearing data set, the currently updated first fault-free data set, the first voltage phase angles corresponding to all first voltage phasors in the currently updated first fault-clearing data set, the second voltage phase angles corresponding to all second voltage phasors, the first voltage phase angles corresponding to all first voltage phasors in the currently updated first fault-free data set, and the second voltage phase angles corresponding to all second voltage phasors.

[0023] Furthermore, the current first fault-clearing dataset, the current first fault-free dataset, and the initialized system recovery dataset are updated according to the current voltage phasor corresponding to the current fault-clearing completion moment to obtain the updated fault-clearing dataset, the updated fault-free dataset, and the updated system recovery dataset, including:

[0024] Calculating a union of the current first fault-clearing dataset and the Cartesian coordinates of the current voltage phasor to obtain the updated fault-clearing dataset;

[0025] Calculating a union of the current first fault-free data set and the Cartesian coordinates of the current voltage phasor to obtain the updated fault-free data set;

[0026] The union of the initialized system recovery data set and the Cartesian coordinates of the current voltage phasor is calculated to obtain the updated system recovery data set.

[0027] Furthermore, the system phase area is calculated based on the updated fault-cleared data set, the updated fault-free data set, and the updated system recovery data set, and judging whether the power system can be restored to stability based on the system phase area includes:

[0028] Obtaining the recovery voltage phasor and recovery voltage phase angle at the time of system recovery;

[0029] Calculating a union of the restored voltage phasor and the updated system restored data set to obtain an updated first system restored data set;

[0030] Calculating the system recovery phase area based on the first system recovery data set and the recovery voltage phase angle;

[0031] Calculating the phase area of ​​the fault-cleared interval based on the updated fault-cleared data set, the updated fault-free data set, the voltage phase angles corresponding to all voltage phasors in the updated fault-cleared data set, and the voltage phase angles corresponding to all voltage phasors in the updated fault-free data set;

[0032] Calculate the sum of the system recovery phase area and the fault clearing interval phase area to obtain the system phase area;

[0033] Comparing the system phase area with the fault phase area limit range;

[0034] If the system phase area is not within the fault phase area limit range, determining that the power system cannot be restored to stability;

[0035] When the system phase area is within the fault phase area limit range, it is determined that the power system can recover stability.

[0036] Furthermore, the fault-clearing interval phase area is calculated based on the updated fault-clearing data set, the updated fault-free data set, the voltage phase angles corresponding to all voltage phasors in the updated fault-clearing data set, and the voltage phase angles corresponding to all voltage phasors in the updated fault-free data set, including:

[0037] Calculating the fault-cleared phase area based on the updated fault-cleared data set and the voltage phase angles corresponding to all voltage phasors in the updated fault-cleared data set;

[0038] Calculate the fault-free phase area based on the updated fault-free data set and the voltage phase angles corresponding to all voltage phasors in the updated fault-free data set;

[0039] The fault-clearing interval phase area is calculated based on the difference between the fault-clearing phase area and the non-fault phase area.

[0040] Furthermore, when the absolute value is not greater than a preset second convergence threshold, obtaining the sampling frequency and sampling time of the phasor measurement unit, and determining whether the power system has restored transient stability based on the sampling frequency, sampling time, and the number of sampling times of the generator include:

[0041] Calculating the sampling times of the phasor measurement unit according to the product of the sampling time and the sampling frequency;

[0042] Add 1 to the sampling times of the above generator to get the upper limit sampling times of the generator;

[0043] If the upper limit sampling number of the generator is greater than the sampling number of the phasor measurement unit, it is determined that the power system has recovered transient stability;

[0044] If the upper limit sampling number of the generator is not greater than the sampling number of the phasor measurement unit, it is determined that the power system has not recovered transient stability.

[0045] Based on the above method embodiment, the present invention provides a corresponding device embodiment;

[0046] The present invention provides a power system transient stability assessment device based on phase area, comprising:

[0047] Data set initialization module, voltage parameter acquisition module, data set update module, absolute value calculation module and transient stability assessment module;

[0048] The data set initialization module is used to initialize the phasor area standard diagram of the power system, and obtain the initialized fault clearing data set, fault-free data set and system recovery data set based on the initialized phasor area standard diagram; wherein the initialized data sets are all 0;

[0049] The voltage parameter acquisition module is used to acquire the voltage phasor of the phasor measurement unit in the power system in real time until the difference between the absolute value of the voltage phasor at the previous moment and the absolute value of the voltage phasor at the current moment is greater than a preset first convergence threshold, clear the fault in the power system, and acquire the first voltage parameter of the phasor measurement unit at the moment before the fault is cleared, the moment when the fault is cleared, and each moment between the moment before the fault is cleared and the moment when the fault is cleared: wherein the first voltage parameter includes: a first voltage phasor, and a first voltage phase angle corresponding to the first voltage phasor;

[0050] The dataset updating module is configured to calculate an updated fault-clearing dataset, an updated fault-free dataset, and an updated system-recovery dataset based on the initialized fault-clearing dataset, the initialized fault-free dataset, the initialized system-recovery dataset, and the first voltage phasors and first voltage phase angles at all times;

[0051] The absolute value calculation module is configured to calculate a system phase area based on the updated fault-cleared data set, the updated fault-free data set, and the updated system recovery data set, determine whether the power system can be restored to stability based on the system phase area, and, if the power system can be restored to stability, calculate the absolute value of the difference between the system phase area at a current moment and the system phase area at a previous moment;

[0052] The transient stability assessment module is configured to obtain the sampling frequency and sampling time of the phasor measurement unit when the absolute value is not greater than a preset second convergence threshold, and determine whether the power system has restored transient stability based on the sampling frequency, sampling time, and the number of sampling times of the generator.

[0053] Based on the above method embodiment, the present invention provides a corresponding terminal device embodiment;

[0054] The present invention provides a terminal device, including a processor, a memory, and a computer program stored in the above-mentioned memory and configured to be executed by the above-mentioned processor. When the above-mentioned processor executes the above-mentioned computer program, it implements the above-mentioned phase area-based power system transient stability assessment method of any embodiment of the present invention.

[0055] Based on the above method embodiment, the present invention provides a storage medium embodiment;

[0056] The present invention provides a storage medium comprising a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the method for transient stability assessment of a power system based on phase area according to any embodiment of the present invention is implemented.

[0057] The embodiments of the present invention have the following beneficial effects:

[0058] The present invention provides a method, apparatus, terminal device and storage medium for transient stability assessment of power system based on phase area. The above method first initializes the phasor area standard diagram of the power system, and obtains the initialized fault clearing data set, fault-free data set and system recovery data set based on the initialized phasor area standard diagram; wherein, the initialized data sets are all 0; then the voltage phasor of the phasor measurement unit in the power system is obtained in real time, until the difference between the absolute value of the above voltage phasor at the previous moment and the absolute value of the above voltage phasor at the current moment is greater than the preset first convergence threshold, the fault in the above power system is cleared, and the first voltage parameter of the above phasor measurement unit at the moment before the fault is cleared, the moment when the fault is cleared and each moment between the moment before the fault is cleared and the moment when the fault is cleared is obtained: wherein, the above first voltage parameter includes: the first voltage phasor, and the first voltage phase angle corresponding to the above first voltage phasor; then, according to the initialized fault clearing data set, the initial The present invention quantifies the transient stability state of the power system based on the phasor area standard diagram and each data set in the phasor area standard diagram. In the entire quantization and evaluation process, the invention does not need to construct a swing equation to estimate the rotor angle of the generator, thereby avoiding the problem of incorrect rotor angle calculation caused by generator instability, thereby reducing the accuracy of transient stability evaluation, and making the evaluation result more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 The present invention provides a flow chart of a method for evaluating transient stability of a power system based on phase area according to an embodiment of the present invention.

[0060] Figure 2 This is a phasor area standard diagram provided by one embodiment of the present invention.

[0061] Figure 3 This is an equivalent time series diagram of the generator G1 provided in one embodiment of the present invention.

[0062] Figure 4 The present invention is a schematic structural diagram of a power system transient stability assessment device based on phase area according to an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0064] like Figure 1 As shown, an embodiment of the present invention provides a method for evaluating transient stability of a power system based on phase area, comprising:

[0065] Step S101: Initializing a phasor area standard diagram of the power system, and obtaining an initialized fault clearing data set, a fault-free data set, and a system recovery data set based on the initialized phasor area standard diagram; wherein the initialized data sets are all 0;

[0066] Specifically, the standard diagram of phasor area is as follows Figure 2 As shown in the figure, based on the phasor area standard diagram, the positive sequence voltage phasor in the phasor measurement unit is converted into the fault time t∈(t o ,t cl ] is the rectangular coordinate phasor to obtain the fault clearance data set S represented by polygon (oado) oado , a fault-free data set represented by a polygon (obco), and a system recovery data set represented by a polygon (odeo). The fault clearing data set contains the origin o=(0,0), the voltage phasor within the fault clearing time and the voltage phasor at the moment when the fault is cleared Therefore, the fault clearance dataset is represented as: The voltage phasor within the polygon (obco) corresponding to the fault-free dataset, including the origin, during the fault clearing time. and the voltage phasor at the moment the fault is cleared in the fault-free data set Therefore, the fault-free dataset is represented as: The system recovery data set contains the voltage phasor at the origin and the moment when the fault is cleared. After the fault is cleared, the time (t cl <t<t m) in the voltage phasor Therefore, the system recovery data set is represented as:

[0067]

[0068] Preferably, when establishing the above-mentioned data sets, the existence of dense channels in the power system is taken into account, and the stability of the power system is evaluated based on the phasor area standard diagram, which has low computational cost and does not require state estimation of the rotor angle.

[0069] Step S102: obtaining a voltage phasor of a phasor measurement unit in the power system in real time until the difference between the absolute value of the voltage phasor at the previous moment and the absolute value of the voltage phasor at the current moment is greater than a preset first convergence threshold, clearing the fault in the power system, and obtaining a first voltage parameter of the phasor measurement unit at a moment before the fault is cleared, a moment when the fault is cleared, and each moment between the moment before the fault is cleared and the moment when the fault is cleared: wherein the first voltage parameter includes: a first voltage phasor, and a first voltage phase angle corresponding to the first voltage phasor;

[0070] Specifically, after the voltage phasors of the phasor measurement units in the power system are acquired in real time, a phasor data concentrator is first used to perform time alignment processing on the synchronous time measurement units of all the phasor measurement units.

[0071] Specifically, it is determined whether the difference between the absolute value of the voltage phasor at the previous moment and the absolute value of the voltage phasor at the current moment is greater than a preset first convergence threshold according to the following formula:

[0072]

[0073] Where, represents the voltage phasor of the kth phasor measurement unit at the previous moment, represents the current voltage phasor of the kth phasor measurement unit, ε TH1 Indicates the preset first convergence threshold.

[0074] Step S103: Calculating an updated fault-clearing dataset, an updated fault-free dataset, and an updated system-recovery dataset based on the initialized fault-clearing dataset, the initialized fault-free dataset, the initialized system-recovery dataset, and the first voltage phasors and first voltage phase angles at all times;

[0075] In a preferred embodiment, the calculation of the updated fault-clearing dataset, the updated fault-free dataset, and the updated system-recovery dataset based on the initialized fault-clearing dataset, the initialized fault-free dataset, the initialized system-recovery dataset, and the first voltage phasors and first voltage phase angles at all times includes:

[0076] Repeat the fault clearing judgment operation until the difference between the absolute value of the first voltage phasor at the next moment and the absolute value of the first voltage phasor at the current moment is greater than a preset third convergence threshold;

[0077] updating the current first fault-clearing dataset, the current first fault-free dataset, and the initialized system recovery dataset according to the current voltage phasor corresponding to the current fault-clearing completion moment, to obtain the updated fault-clearing dataset, the updated fault-free dataset, and the updated system recovery dataset;

[0078] The above-mentioned fault clearing judgment operation includes:

[0079] After the current fault is cleared, obtaining a current second voltage parameter of the phasor measurement unit at the current fault clearing completion moment and at each moment between the current fault clearing completion moment and the first fault clearing completion moment; wherein the current second voltage parameter includes: a current second voltage phasor and a current second voltage phase angle, and an initial second voltage parameter is 0;

[0080] Calculating a phase area of ​​a current fault-clearing interval according to a current first fault-clearing data set, a current first fault-free data set, a current second voltage phasor, and the first voltage phasor;

[0081] Calculating a fault phase area limit range based on the first voltage phase angle corresponding to the moment before the fault is cleared in the first voltage phase angle, and obtaining the first voltage phasor of the phasor measurement unit at the current moment and the next moment when the phase area of ​​the current fault clearing interval is within the fault phase area limit range;

[0082] Specifically, if the phase area of ​​the current fault clearing interval is not within the fault phase area limit range, it indicates that the current power system cannot be maintained stable and an alarm is issued.

[0083] Specifically, the fault phase area limit range is calculated according to the following formula:

[0084]

[0085] θ max =π-θ o

[0086]

[0087] Where A MM Indicates the fault phase area limit range, SAL indicates the total area of ​​the phasor area standard diagram, θ max Indicates the maximum voltage phase angle, θ oIndicates the first voltage phase angle corresponding to the moment before the fault is cleared, as well as is the value range of the maximum voltage phase angle, as well as The first voltage phase angle θ corresponding to the moment before the fault is cleared o The value range of .

[0088] Specifically, according to the above formula, the minimum value of the fault phase area limit range can be calculated as:

[0089]

[0090] The maximum value is:

[0091]

[0092] If the difference between the absolute value of the first voltage phasor at the next moment and the absolute value of the first voltage phasor at the current moment is not greater than the preset third convergence threshold, the fault of the power system is cleared again.

[0093] Specifically, it is determined whether the difference between the absolute value of the first voltage phasor at the next moment and the absolute value of the first voltage phasor at the current moment is greater than a preset third convergence threshold according to the following formula:

[0094]

[0095] Where, ε TH2 Indicates the preset third convergence threshold.

[0096] Preferably, the fault phase area limit range is %A MM It is a monotonically increasing parameter. Using this monotonically increasing parameter to quantify the stability of the power system can avoid the influence of false triggering caused by multiple crossings of the threshold.

[0097] In this preferred embodiment, the fault-clearing judgment operation is repeatedly performed until the difference between the absolute value of the first voltage phasor at the next moment and the absolute value of the first voltage phasor at the current moment is greater than a preset third convergence threshold. Then, the current first fault-clearing dataset, the current first fault-free dataset, and the initialized system recovery dataset are updated according to the current voltage phasor corresponding to the current fault-clearing completion moment to obtain an updated fault-clearing dataset, an updated fault-free dataset, and an updated system recovery dataset.

[0098] In another preferred embodiment, the calculating of the current fault-clearing interval phase area based on the current first fault-clearing data set, the current first fault-free data set, the current second voltage phasor, and the first voltage phasor includes:

[0099] Calculating a union of a current first fault-clearing data set, the first voltage phasor, and the current second voltage phasor to obtain a current updated first fault-clearing data set; wherein the initial first fault-clearing data set is the initialized fault-clearing data set;

[0100] Specifically, the time when the fault is cleared is recorded as t cl , the moment before the fault is cleared is recorded as t0, and the moment of fault clearing is recorded as t0+1, so for the fault clearing time period (t0 <t<t cl ), add and The Cartesian coordinates of , therefore, the updated first fault clearance data set is calculated according to the following formula:

[0101]

[0102] Where, represents the updated first fault clearing dataset at time t, represents the first fault-clearing dataset at time t before the update, represents the total voltage phasor of the first voltage phasor and the second voltage phasor corresponding to the first fault data set at time t.

[0103] Calculating the union of the current first fault-free data set, the first voltage phasor, and the current second voltage phasor to obtain the current updated first fault-free data set; wherein the initial first fault-free data set is the initialized fault-free data set;

[0104] Specifically, the updated first fault-free data set is calculated according to the following formula:

[0105]

[0106] Where, represents the first fault-free data set at time t after update, represents the first fault-free data set at time t before the update, represents the total voltage phasor of the first voltage phasor and the second voltage phasor corresponding to the first fault-free data set at time t.

[0107] The phase area of ​​the current fault-clearing interval is calculated based on the currently updated first fault-clearing data set, the currently updated first fault-free data set, the first voltage phase angles corresponding to all first voltage phasors in the currently updated first fault-clearing data set, the second voltage phase angles corresponding to all second voltage phasors, the first voltage phase angles corresponding to all first voltage phasors in the currently updated first fault-free data set, and the second voltage phase angles corresponding to all second voltage phasors.

[0108] Specifically, the phase area of ​​the fault clearing interval is calculated according to the following formula:

[0109]

[0110] Where, dA=dVdθ, f(A1) represents the phase area of ​​the fault clearing interval, that is, Figure 2 A1 area in θ cl The second voltage phase angle when the fault is cleared is θ mm It represents the first voltage phase angle of the first fault-free data set after the current update, the second voltage phase angle of the first fault-free data set after the current update, and the voltage phase angle corresponding to the voltage phasor in the first system recovery data set.

[0111] Schematically, θ mm That is Figure 2 Medium voltage phasor The corresponding voltage phase angle.

[0112] In this preferred embodiment, the current fault-clearing interval phase area is calculated based on the current first fault-clearing data set, the current first fault-free data set, the current second voltage phasor, and the first voltage phasor.

[0113] In another preferred embodiment, the updating of the current first fault-clearing dataset, the current first fault-free dataset, and the initialized system recovery dataset according to the current voltage phasor corresponding to the current fault-clearing completion moment to obtain the updated fault-clearing dataset, the updated fault-free dataset, and the updated system recovery dataset includes:

[0114] Calculating a union of the current first fault-clearing dataset and the Cartesian coordinates of the current voltage phasor to obtain the updated fault-clearing dataset;

[0115] Specifically, the updated fault clearance data set is obtained according to the following formula:

[0116]

[0117] Where, Represents the updated t clThe fault clearance dataset at time t, Indicates t before update cl The fault clearance dataset at time t, Indicates t cl The current voltage phasor corresponding to the moment, t cl The time indicates the time when the fault is cleared.

[0118] Calculating a union of the current first fault-free data set and the Cartesian coordinates of the current voltage phasor to obtain the updated fault-free data set;

[0119] Specifically, the updated fault-free data set is obtained according to the following formula:

[0120]

[0121] Where, Represents the updated t cl The fault-free dataset at time t, Indicates t before update cl Fault-free dataset at time.

[0122] The union of the initialized system recovery data set and the Cartesian coordinates of the current voltage phasor is calculated to obtain the updated system recovery data set.

[0123] Specifically, the updated system recovery data set is calculated according to the following formula:

[0124]

[0125] Where, Represents the updated t cl The system recovery data set at the moment, Indicates t before update cl System recovery data set at the moment.

[0126] In this preferred embodiment, the current first fault-clearing dataset, the current first fault-free dataset, and the initialized system recovery dataset are updated according to the current voltage phasor corresponding to the current fault-clearing completion moment, thereby obtaining the updated fault-clearing dataset, the updated fault-free dataset, and the updated system recovery dataset.

[0127] Step S104: Calculating a system phase area based on the updated fault-cleared data set, the updated fault-free data set, and the updated system-recovered data set. Determining whether the power system can be restored to stability based on the system phase area. If the power system can be restored to stability, calculating the absolute value of the difference between the system phase area at the current moment and the system phase area at the previous moment.

[0128] In a preferred embodiment, the system phase area is calculated based on the updated fault-cleared data set, the updated fault-free data set, and the updated system recovery data set, and determining whether the power system can be restored to stability based on the system phase area includes:

[0129] Obtaining the recovery voltage phasor and recovery voltage phase angle at the time of system recovery;

[0130] Calculating a union of the restored voltage phasor and the updated system restored data set to obtain an updated first system restored data set;

[0131] Calculating the system recovery phase area based on the first system recovery data set and the recovery voltage phase angle;

[0132] Specifically, the system recovery phase area is calculated according to the following formula:

[0133]

[0134] Where f(A2) represents the system recovery phase area, θ m Indicates the recovery voltage phase angle.

[0135] Calculating the phase area of ​​the fault-cleared interval based on the updated fault-cleared data set, the updated fault-free data set, the voltage phase angles corresponding to all voltage phasors in the updated fault-cleared data set, and the voltage phase angles corresponding to all voltage phasors in the updated fault-free data set;

[0136] Calculate the sum of the system recovery phase area and the fault clearing interval phase area to obtain the system phase area;

[0137] Specifically, the system phase area is calculated according to the following formula:

[0138] A GZ =f(A1)+f(A2)

[0139] Where A GZ represents the phase area of ​​the above system.

[0140] Comparing the system phase area with the fault phase area limit range;

[0141] If the system phase area is not within the fault phase area limit range, determining that the power system cannot be restored to stability;

[0142] Specifically, when it is determined that the power system cannot be restored to stability, an alarm is issued.

[0143] When the system phase area is within the fault phase area limit range, it is determined that the power system can recover stability.

[0144] In this preferred embodiment, the system phase area is calculated based on the updated fault-cleared data set, the updated fault-free data set, and the updated system recovery data set, and whether the power system can be restored to stability is determined based on the system phase area.

[0145] In another preferred embodiment, the fault-clearing interval phase area is calculated based on the updated fault-clearing dataset, the updated fault-free dataset, the voltage phase angles corresponding to all voltage phasors in the updated fault-clearing dataset, and the voltage phase angles corresponding to all voltage phasors in the updated fault-free dataset, including:

[0146] Calculating the fault-cleared phase area based on the updated fault-cleared data set and the voltage phase angles corresponding to all voltage phasors in the updated fault-cleared data set;

[0147] Calculate the fault-free phase area based on the updated fault-free data set and the voltage phase angles corresponding to all voltage phasors in the updated fault-free data set;

[0148] The fault-clearing interval phase area is calculated based on the difference between the fault-clearing phase area and the non-fault phase area.

[0149] Specifically, from Figure 2 From the perspective of fault clearing phase area, Figure 2 In the polygonal (oado) area, the fault-free phase area is Figure 2 The polygon (obco) part in the fault clearance interval is Figure 2 The phase area of ​​the fault clearing interval can be obtained by integral calculation.

[0150] In this preferred embodiment, the fault-clearing interval phase area is calculated based on the updated fault-clearing data set, the updated fault-free data set, the voltage phase angles corresponding to all voltage phasors in the updated fault-clearing data set, and the voltage phase angles corresponding to all voltage phasors in the updated fault-free data set.

[0151] Step S105: When the absolute value is not greater than the preset second convergence threshold, the sampling frequency and sampling time of the phasor measurement unit are obtained, and whether the power system recovers transient stability is determined based on the sampling frequency, sampling time and the number of sampling times of the generator.

[0152] Specifically, whether the absolute value is not greater than the preset second convergence threshold is determined according to the following formula:

[0153] |A GZ (t)-A GZ (t-1)|≤ε conv

[0154] Where A GZ (t) represents the system phase area at time t, A GZ (t-1) represents the system phase area at time t-1, ε conv Indicates the preset second convergence threshold.

[0155] Specifically, if the absolute value is greater than the preset second convergence threshold, the generator's Count parameter is set to 0, the next moment is used as the system recovery moment, the voltage phasor and voltage phase angle at the next moment are used as the updated system recovery voltage phasor and system recovery voltage phase angle, and the system recovery data set is updated. The calculation is then repeated according to the contents of step S104 to obtain a new absolute value, and the absolute value is re-compared with the preset second convergence threshold. The system recovery data set is updated according to the following formula:

[0156]

[0157] Where, represents the updated system recovery dataset at time t, represents the system recovery dataset at time t before the update, It represents the system restored voltage phasor after the above update.

[0158] In a preferred embodiment, when the absolute value is not greater than a preset second convergence threshold, obtaining the sampling frequency and sampling time of the phasor measurement unit, and determining whether the power system has restored transient stability based on the sampling frequency, sampling time, and the number of sampling times of the generator include:

[0159] Calculating the sampling times of the phasor measurement unit according to the product of the sampling time and the sampling frequency;

[0160] Specifically, the sampling times of the phasor measurement unit are calculated according to the following formula:

[0161] C th =T×f

[0162] Where C th represents the sampling times of the phasor measurement unit, T represents the continuous sampling time of the phasor measurement unit, and f represents the sampling frequency of the phasor measurement unit.

[0163] Add 1 to the sampling times of the above generator to get the upper limit sampling times of the generator;

[0164] If the upper limit sampling number of the generator is greater than the sampling number of the phasor measurement unit, it is determined that the power system has recovered transient stability;

[0165] If the upper limit sampling number of the generator is not greater than the sampling number of the phasor measurement unit, it is determined that the power system has not recovered transient stability.

[0166] Specifically, if it is determined that the power system has not restored transient stability, the next moment is used as the system recovery moment, the voltage phasor and voltage phase angle at the next moment are used as the updated system recovery voltage phasor and system recovery voltage phase angle, and the system recovery data set is updated. The new absolute value is calculated again according to the content of step S104, and the absolute value is re-compared with the preset second convergence threshold.

[0167] In this preferred embodiment, whether the power system recovers transient stability is determined based on the sampling frequency, the sampling time, and the number of sampling times of the generator.

[0168] In another preferred embodiment, the power system consists of four generators, G1 and G2 generators are located in the first area, and G3 and G4 generators are located in the second area. TH1 =0.15, preset the third convergence threshold ε TH2 =0.2, preset the third convergence threshold ε conv =0.001, duration is 3s. Apply t cl = 0.5s and t cl =0.125s three-phase fault, the fault resistance is 2Ω. After executing the power system transient stability assessment method based on phase area provided by the present invention, the equivalent time series diagram of generator G1 is obtained when the fault clearing time is 0.5s and 0.125s respectively. Figure 3 As shown, it can be seen that t cl = 0.5s, the system becomes unstable during the period from 6.5s to 7.26s because %A GZ Exceeds the fault phase area limit range %A MM The upper limit of t cl = 0.125s, the convergence criterion is met within the continuous time of T = 3S, the system remains stable, and after the fault is cleared %A GZ Maintain a constant value.

[0169] Based on the above method embodiments, the present invention provides corresponding device embodiments.

[0170] like Figure 4 As shown, an embodiment of the present invention provides a power system transient stability assessment device based on phase area, comprising:

[0171] Data set initialization module, voltage parameter acquisition module, data set update module, absolute value calculation module and transient stability assessment module;

[0172] The data set initialization module is used to initialize the phasor area standard diagram of the power system, and obtain the initialized fault clearing data set, fault-free data set and system recovery data set based on the initialized phasor area standard diagram; wherein the initialized data sets are all 0;

[0173] The voltage parameter acquisition module is used to acquire the voltage phasor of the phasor measurement unit in the power system in real time until the difference between the absolute value of the voltage phasor at the previous moment and the absolute value of the voltage phasor at the current moment is greater than a preset first convergence threshold, clear the fault in the power system, and acquire the first voltage parameter of the phasor measurement unit at the moment before the fault is cleared, the moment when the fault is cleared, and each moment between the moment before the fault is cleared and the moment when the fault is cleared: wherein the first voltage parameter includes: a first voltage phasor, and a first voltage phase angle corresponding to the first voltage phasor;

[0174] The dataset updating module is configured to calculate an updated fault-clearing dataset, an updated fault-free dataset, and an updated system-recovery dataset based on the initialized fault-clearing dataset, the initialized fault-free dataset, the initialized system-recovery dataset, and the first voltage phasors and first voltage phase angles at all times;

[0175] The absolute value calculation module is configured to calculate a system phase area based on the updated fault-cleared data set, the updated fault-free data set, and the updated system recovery data set, determine whether the power system can be restored to stability based on the system phase area, and, if the power system can be restored to stability, calculate the absolute value of the difference between the system phase area at a current moment and the system phase area at a previous moment;

[0176] The transient stability assessment module is configured to obtain the sampling frequency and sampling time of the phasor measurement unit when the absolute value is not greater than a preset second convergence threshold, and determine whether the power system has restored transient stability based on the sampling frequency, sampling time, and the number of sampling times of the generator.

[0177] It should be noted that the device embodiments described above are merely schematic, wherein the modules described above as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical modules, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between the modules indicates that there is a communication connection between them, which can be specifically implemented as one or more communication buses or signal lines. A person of ordinary skill in the art can understand and implement it without making any creative effort. The above schematic diagram is merely an example of a power system transient stability assessment device based on phase area, and does not constitute a limitation on a power system transient stability assessment device based on phase area, and may include more or fewer components than shown in the figure, or a combination of certain components, or different components.

[0178] Based on the above method embodiment, the present invention provides a corresponding terminal device embodiment.

[0179] Another embodiment of the present invention provides a terminal device, including a processor, a memory, and a computer program stored in the above-mentioned memory and configured to be executed by the above-mentioned processor. When the above-mentioned processor executes the above-mentioned computer program, it implements the above-mentioned phase area-based power system transient stability assessment method in any embodiment of the present invention.

[0180] For example, in this embodiment, the computer program may be divided into one or more modules, which are stored in the memory and executed by the processor to implement the present invention. The one or more modules may be a series of computer program instruction segments capable of performing specific functions, which are used to describe the execution process of the computer program in the device.

[0181] The terminal device may be a computing device such as a desktop computer, a notebook computer, a PDA, or a cloud server. The device may include, but is not limited to, a processor and a memory;

[0182] The processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor. The processor is the control center of the device, connecting the various parts of the device using various interfaces and lines.

[0183] The above-mentioned memory can be used to store the above-mentioned computer programs and / or modules. The above-mentioned processor realizes various functions of the above-mentioned device by running or executing the computer programs and / or modules stored in the above-mentioned memory, and calling the data stored in the memory. The above-mentioned memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required for a function, etc.; in addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage device.

[0184] Based on the above method embodiment, the present invention provides a corresponding storage medium embodiment.

[0185] Another embodiment of the present invention provides a storage medium, which includes a stored computer program, wherein when the computer program is running, the device where the storage medium is located is controlled to execute the phase area-based power system transient stability assessment method described in any embodiment of the present invention.

[0186] In this embodiment, the storage medium is a computer-readable storage medium, and the computer program includes computer program code, which may be in source code form, object code form, an executable file, or some intermediate form. The computer-readable medium may include any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunications signal, and a software distribution medium.

[0187] Compared with the prior art, by implementing the above-mentioned embodiments of the present invention, the accuracy of the transient stability assessment results of the power system can be improved.

[0188] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for evaluating transient stability of a power system based on phase area, characterized in that: include: Initializing the phasor area standard diagram of the power system, and obtaining an initialized fault clearing data set, a fault-free data set, and a system recovery data set based on the initialized phasor area standard diagram; wherein the initialized data sets are all 0; Acquire a voltage phasor of a phasor measurement unit in a power system in real time, until the difference between the absolute value of the voltage phasor at a previous moment and the absolute value of the voltage phasor at a current moment is greater than a preset first convergence threshold, clear the fault in the power system, and acquire a first voltage parameter of the phasor measurement unit at a moment before the fault is cleared, a moment when the fault is cleared, and each moment between the moment before the fault is cleared and the moment when the fault is cleared: wherein the first voltage parameter includes: a first voltage phasor, and a first voltage phase angle corresponding to the first voltage phasor; Repeating the fault clearing determination operation until the difference between the absolute value of the first voltage phasor at the next moment and the absolute value of the first voltage phasor at the current moment is greater than a preset third convergence threshold; updating the current first fault clearing dataset, the current first fault-free dataset, and the initialized system recovery dataset according to the current voltage phasor corresponding to the current fault clearing completion moment to obtain an updated fault clearing dataset, an updated fault-free dataset, and an updated system recovery dataset; The fault clearing judgment operation includes: After the current fault is cleared, the current second voltage parameter of the phasor measurement unit is obtained at the current fault clearing completion moment and each moment between the current fault clearing completion moment and the first fault clearing completion moment; wherein, the current second voltage parameter includes: the current second voltage phasor and the current second voltage phase angle, and the initial second voltage parameter is 0; the current fault clearing interval phase area is calculated based on the current first fault clearing data set, the current first fault-free data set, the current second voltage phasor and the first voltage phasor; the fault phase area limit range is calculated based on the first voltage phase angle corresponding to the moment before the fault clearing in the first voltage phase angle, and when the current fault clearing interval phase area is within the fault phase area limit range, the first voltage phasor of the phasor measurement unit at the current moment and the next moment is obtained; if the difference between the absolute value of the first voltage phasor at the next moment and the absolute value of the first voltage phasor at the current moment is not greater than the preset third convergence threshold, the power system is fault cleared again; calculating a system phase area based on the updated fault-cleared data set, the updated fault-free data set, and the updated system recovery data set, determining whether the power system can be restored to stability based on the system phase area, and if the power system can be restored to stability, calculating an absolute value of a difference between the system phase area at a current moment and the system phase area at a previous moment; When the absolute value of the difference between the system phase area at the current moment and the system phase area at the previous moment is not greater than a preset second convergence threshold, the sampling frequency and sampling time of the phasor measurement unit are obtained, and it is determined whether the power system has restored transient stability based on the sampling frequency, sampling time and the number of sampling times of the generator.

2. A method for evaluating power system transient stability based on phase area according to claim 1, characterized in that: The calculating the phase area of ​​the current fault-clearing interval according to the current first fault-clearing data set, the current first fault-free data set, the current second voltage phasor, and the first voltage phasor includes: Calculating a union of a current first fault-clearing data set, the first voltage phasor, and the current second voltage phasor to obtain a current updated first fault-clearing data set; wherein the initial first fault-clearing data set is the initialized fault-clearing data set; Calculating a union of a current first fault-free data set, the first voltage phasor, and the current second voltage phasor to obtain a current updated first fault-free data set; wherein the initial first fault-free data set is the initialized fault-free data set; The phase area of ​​the current fault-clearing interval is calculated based on the currently updated first fault-clearing data set, the currently updated first fault-free data set, the first voltage phase angles corresponding to all first voltage phasors in the currently updated first fault-clearing data set, the second voltage phase angles corresponding to all second voltage phasors, the first voltage phase angles corresponding to all first voltage phasors in the currently updated first fault-free data set, and the second voltage phase angles corresponding to all second voltage phasors.

3. The method for evaluating power system transient stability based on phase area according to claim 2, characterized in that: The updating of the current first fault-clearing data set, the current first fault-free data set, and the initialized system recovery data set according to the current voltage phasor corresponding to the current fault-clearing completion moment to obtain an updated fault-clearing data set, an updated fault-free data set, and an updated system recovery data set includes: Calculating a union of the current first fault-clearing data set and the Cartesian coordinates of the current voltage phasor to obtain the updated fault-clearing data set; Calculating a union of the current first fault-free data set and the Cartesian coordinates of the current voltage phasor to obtain the updated fault-free data set; A union of the initialized system recovery data set and the Cartesian coordinates of the current voltage phasor is calculated to obtain the updated system recovery data set.

4. The method for evaluating power system transient stability based on phase area according to claim 3, characterized in that: The calculating of the system phase area based on the updated fault-cleared data set, the updated fault-free data set, and the updated system recovery data set, and determining whether the power system can be restored to stability based on the system phase area, includes: Obtaining the recovery voltage phasor and recovery voltage phase angle at the time of system recovery; calculating a union of the restored voltage phasor and the updated system restored data set to obtain an updated first system restored data set; Calculating a system recovery phase area according to the first system recovery data set and the recovery voltage phase angle; Calculating a fault-clearing interval phase area based on the updated fault-clearing data set, the updated fault-free data set, the voltage phase angles corresponding to all voltage phasors in the updated fault-clearing data set, and the voltage phase angles corresponding to all voltage phasors in the updated fault-free data set; Calculating the sum of the system recovery phase area and the fault clearing interval phase area to obtain the system phase area; Comparing the system phase area with the fault phase area limit range; If the system phase area is not within the fault phase area limit range, determining that the power system cannot be restored to stability; When the system phase area is within the fault phase area limit range, it is determined that the power system can be restored to stability.

5. The method for evaluating power system transient stability based on phase area according to claim 4, characterized in that: The calculating the fault-clearing interval phase area according to the updated fault-clearing data set, the updated fault-free data set, the voltage phase angles corresponding to all voltage phasors in the updated fault-clearing data set, and the voltage phase angles corresponding to all voltage phasors in the updated fault-free data set includes: Calculating a fault-cleared phase area based on the updated fault-cleared data set and voltage phase angles corresponding to all voltage phasors in the updated fault-cleared data set; Calculating a non-fault phase area based on the updated non-fault data set and the voltage phase angles corresponding to all voltage phasors in the updated non-fault data set; The fault-clearing interval phase area is calculated based on the difference between the fault-clearing phase area and the fault-free phase area.

6. A method for evaluating power system transient stability based on phase area according to claim 5, characterized in that: When the absolute value of the difference between the system phase area at the current moment and the system phase area at the previous moment is not greater than a preset second convergence threshold, obtaining the sampling frequency and sampling time of the phasor measurement unit, and determining whether the power system has restored transient stability based on the sampling frequency, sampling time, and the number of sampling times of the generator, including: Calculating the sampling times of the phasor measurement unit according to the product of the sampling time and the sampling frequency; Add 1 to the sampling times of the generator to obtain the upper limit sampling times of the generator; If the upper limit sampling number of the generator is greater than the sampling number of the phasor measurement unit, it is determined that the power system has recovered transient stability; If the upper limit sampling number of the generator is not greater than the sampling number of the phasor measurement unit, it is determined that the power system has not recovered transient stability.

7. A power system transient stability assessment device based on phase area, characterized in that: include: Data set initialization module, voltage parameter acquisition module, data set update module, absolute value calculation module and transient stability assessment module; The data set initialization module is used to initialize the phasor area standard diagram of the power system, and obtain the initialized fault clearing data set, fault-free data set and system recovery data set based on the initialized phasor area standard diagram; wherein the initialized data sets are all 0; The voltage parameter acquisition module is used to acquire the voltage phasor of the phasor measurement unit in the power system in real time, until the difference between the absolute value of the voltage phasor at the previous moment and the absolute value of the voltage phasor at the current moment is greater than a preset first convergence threshold, clear the fault in the power system, and acquire the first voltage parameter of the phasor measurement unit at the moment before the fault is cleared, the moment when the fault is cleared, and each moment between the moment before the fault is cleared and the moment when the fault is cleared: wherein the first voltage parameter includes: a first voltage phasor, and a first voltage phase angle corresponding to the first voltage phasor; The data set updating module is configured to repeatedly perform a fault clearing determination operation until a difference between an absolute value of a first voltage phasor at a next moment and an absolute value of the first voltage phasor at a current moment is greater than a preset third convergence threshold; and to update a current first fault clearing data set, a current first fault-free data set, and an initialized system recovery data set based on a current voltage phasor corresponding to a current fault clearing completion moment, to obtain an updated fault clearing data set, an updated fault-free data set, and an updated system recovery data set; The fault clearing judgment operation includes: After the current fault is cleared, the current second voltage parameter of the phasor measurement unit is obtained at the current fault clearing completion moment and each moment between the current fault clearing completion moment and the first fault clearing completion moment; wherein, the current second voltage parameter includes: the current second voltage phasor and the current second voltage phase angle, and the initial second voltage parameter is 0; the current fault clearing interval phase area is calculated based on the current first fault clearing data set, the current first fault-free data set, the current second voltage phasor and the first voltage phasor; the fault phase area limit range is calculated based on the first voltage phase angle corresponding to the moment before the fault clearing in the first voltage phase angle, and when the current fault clearing interval phase area is within the fault phase area limit range, the first voltage phasor of the phasor measurement unit at the current moment and the next moment is obtained; if the difference between the absolute value of the first voltage phasor at the next moment and the absolute value of the first voltage phasor at the current moment is not greater than the preset third convergence threshold, the power system is fault cleared again; The absolute value calculation module is configured to calculate a system phase area based on the updated fault-cleared data set, the updated fault-free data set, and the updated system recovery data set, determine whether the power system can be restored to stability based on the system phase area, and, if the power system can be restored to stability, calculate the absolute value of the difference between the system phase area at a current moment and the system phase area at a previous moment; The transient stability assessment module is configured to obtain a sampling frequency and a sampling time of the phasor measurement unit when the absolute value of the difference between the system phase area at a current moment and the system phase area at a previous moment is not greater than a preset second convergence threshold, and determine whether the power system has restored transient stability based on the sampling frequency, the sampling time, and the number of sampling times of the generator.

8. A terminal device, characterized in that: The method comprises a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein when the processor executes the computer program, the method for transient stability assessment of a power system based on phase area according to any one of claims 1 to 6 is implemented.

9. A storage medium, characterized in that: The storage medium includes a stored computer program, wherein when the computer program is running, the device where the storage medium is located is controlled to execute the power system transient stability assessment method based on phase area according to any one of claims 1 to 6.

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