Generator stator corona degradation monitoring method and system based on partial discharge

Abstract

The invention provides a generator stator corona degradation monitoring method and system based on partial discharge, and the method comprises the steps: obtaining a multi-fault superposition global PRPD atlas of a generator stator at each moment in a preset time period, and marking a plurality of corona discharge local atlas regions in the multi-fault superposition global PRPD atlas; obtaining each pulse amplitude and the discharge quantity under each pulse phase in the positive polarity partial discharge pulse and each pulse amplitude and the discharge quantity under each pulse phase of the negative polarity partial discharge pulse of the generator stator at each moment in the preset time period; determining a discharge pulse duty ratio, a discharge pulse number and a discharge pulse amplitude in each corona discharge local map area at each moment in the preset time period; and determining whether the corona performance of the generator stator is degraded or not according to the discharge pulse duty ratio, the discharge pulse number and the discharge pulse amplitude. According to the technical scheme provided by the invention, the corona state of the insulation partial discharge of the original generator can be accurately and effectively monitored.

Description

Technical Field

[0001] The present application relates to the technical field of insulation status monitoring of generators in smart power plants, and in particular to a method and system for monitoring corona degradation of generator stators based on partial discharge. Background Art

[0002] Large generators are the core components of power generation in power plants. According to literature statistics, more than 40% of shutdown events are caused by stator insulation failure. In order to predict the insulation status in advance and avoid unplanned shutdown events, an insulation partial discharge monitoring system is installed on the stator winding of the generator. The insulation status is judged by continuously detecting the changes in the partial discharge amplitude characteristics, and planned maintenance and repair are carried out according to the insulation status to restore the insulation performance. However, in engineering applications, the stator insulation of large generators is a distributed system, and multiple types of faults with different risks are superimposed in the system. For the overall partial discharge detection of the phase winding, its mode diagram is an overall global mode, and its discharge amplitude only represents the discharge fault with the largest discharge amount, which may be external interference, metal tip discharge, and is not a high-risk fault discharge for the insulation system. The higher-risk insulation internal discharge, corona discharge, and slot discharge are often reflected only in the local part of the mode diagram due to propagation attenuation and the amplitude is small. Therefore, the comprehensive amplitude characteristics of the existing monitoring system for insulation partial discharge cannot effectively monitor the development of insulation degradation, and even insulation fault shutdown occurs without abnormal reflection of the monitoring system, and online monitoring fails. The stator corona problem of large air-cooled generators and the degradation of insulation anti-corona performance are relatively prominent stator insulation problems in large hydro-turbine generators in recent years. It is necessary to study the local discharge characteristics of the corona problem and carry out targeted continuous monitoring. Summary of the invention

[0003] The present application provides a method and system for monitoring the corona degradation of a generator stator based on partial discharge, so as to at least solve the technical problem that the prior art cannot effectively monitor the development of insulation corona degradation.

[0004] The first embodiment of the present application proposes a method for monitoring the corona degradation of a generator stator based on partial discharge, the method comprising:

[0005] Obtaining a multi-fault superimposed global PRPD spectrum of the generator stator at each moment within a preset time period, and marking a plurality of corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum;

[0006] Based on the multi-fault superposition global PRPD spectrum of the generator stator at each moment in a preset time period, the number of discharges at each pulse amplitude and each pulse phase in the positive polarity partial discharge pulse of the generator stator and the number of discharges at each pulse amplitude and each pulse phase in the negative polarity partial discharge pulse are obtained;

[0007] Determine the discharge pulse duty ratio, discharge pulse number, and discharge pulse amplitude in each corona discharge local spectrum region at each moment in the preset time period according to each pulse amplitude and the discharge number at each pulse phase in the positive polarity local discharge pulse, and each pulse amplitude and the discharge number at each pulse phase in the negative polarity local discharge pulse;

[0008] Whether the corona performance of the generator stator is deteriorated is determined according to the discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period.

[0009] Preferably, the marking of multiple corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum includes:

[0010] Obtain the phase angle ranges when the generator stator discharges;

[0011] Based on the phase angle ranges, a plurality of corona discharge local spectrum regions are marked in the multi-fault superposition global PRPD spectrum at each moment within the preset time period.

[0012] Further, the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period are determined according to each pulse amplitude in the positive polarity local discharge pulse and the number of discharges at each pulse phase, and each pulse amplitude in the negative polarity local discharge pulse and the number of discharges at each pulse phase, including:

[0013] Constructing a three-dimensional array at each moment in the preset time period according to each pulse amplitude and the number of discharges at each pulse phase in the positive polarity partial discharge pulse, and each pulse amplitude and the number of discharges at each pulse phase in the negative polarity partial discharge pulse;

[0014] The discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period are determined respectively according to the three-dimensional array at each moment in the preset time period.

[0015] Furthermore, the three-dimensional array at each moment in the preset time period is constructed according to each pulse amplitude and the discharge quantity at each pulse phase in the positive polarity partial discharge pulse at each moment in the preset time period, and each pulse amplitude and the discharge quantity at each pulse phase in the negative polarity partial discharge pulse, including:

[0016] Number the pulse amplitudes of the negative polarity partial discharge pulse at the i-th moment to the pulse amplitudes of the positive polarity partial discharge pulse in sequence from zero, and use the pulse amplitude numbers as the y coordinates;

[0017] Numbering each pulse phase in the positive polarity partial discharge pulse and each pulse phase in the negative polarity partial discharge pulse at the i-th moment in sequence from zero, and using each pulse phase as an x-coordinate;

[0018] The pulse amplitudes and discharge numbers under each pulse phase in the positive polarity partial discharge pulse at the i-th moment, and the pulse amplitudes and discharge numbers under each pulse phase in the negative polarity partial discharge pulse are respectively used as the z coordinates under the corresponding pulse amplitudes and pulse phases;

[0019] Constructing a three-dimensional array at the i-th moment based on the y-coordinate, x-coordinate and z-coordinate at the i-th moment;

[0020] Where i belongs to I, and I is the total number of moments in the preset time period.

[0021] Furthermore, the three-dimensional array at each moment in the preset time period is used to determine the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period, including:

[0022] Determine the abscissa and ordinate of the lower left corner and the abscissa and ordinate of the upper right corner of each corona discharge local spectrum region at each moment in the preset time period based on the three-dimensional array at each moment in the preset time period;

[0023] Determine the first coordinate of the lower left corner and the first coordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period according to the abscissa and ordinate of the lower left corner and the abscissa and ordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period;

[0024] Obtaining the number of discharges in each corona discharge local spectrum area at each moment in the preset time period;

[0025] Determine the discharge pulse duty ratio and the discharge pulse quantity in the corona discharge local spectrum region according to the discharge quantity in the corona discharge local spectrum region, the first coordinate of the lower left corner and the first coordinate of the upper right corner of the corona discharge local spectrum region;

[0026] The discharge pulse amplitude in the corona discharge local spectrum region is determined according to the first coordinate of the lower left corner and the first coordinate of the upper right corner of the corona discharge local spectrum region.

[0027] Further, the method of determining the first coordinates of the lower left corner and the first coordinates of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period according to the abscissa and the ordinate of the lower left corner and the abscissa and the ordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period includes:

[0028] Divide the abscissa of the lower left corner by the preset granularity to obtain the abscissa of the first coordinate of the lower left corner, and use the ordinate of the lower left corner as the ordinate of the first coordinate of the lower left corner;

[0029] The horizontal coordinate of the upper right corner is divided by a preset granularity to obtain the horizontal coordinate of the first coordinate of the upper right corner, and the vertical coordinate of the upper right corner is used as the vertical coordinate of the first coordinate of the upper right corner.

[0030] Furthermore, the calculation formula of the discharge pulse duty cycle in the local spectrum area of ​​the corona discharge is as follows:

[0031] K s =H / ((x2-x1+1)*(y2-y1+1))

[0032] In the formula, K s is the discharge pulse duty ratio in the sth corona discharge local spectrum area, H is the discharge quantity in the sth corona discharge local spectrum area, x1 is the abscissa of the first coordinate in the lower left corner, y1 is the ordinate of the first coordinate in the lower left corner, x2 is the abscissa of the first coordinate in the upper right corner, and y2 is the ordinate of the first coordinate in the upper right corner;

[0033] The calculation formula for the number of discharge pulses in the local spectrum area of ​​the corona discharge is as follows:

[0034]

[0035] Where NQN s is the number of discharge pulses in the sth corona discharge local spectrum area, NQNX s is, z is the number of discharges;

[0036] The calculation formula of the discharge pulse amplitude in the local spectrum area of ​​the corona discharge is as follows:

[0037]

[0038] In the formula, QM s is the discharge pulse amplitude in the sth corona discharge local spectrum area, R is the upper limit of the range, and F is the number of panes of the amplitude.

[0039] Further, the method of determining whether the corona performance of the generator stator is deteriorated according to the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period includes:

[0040] The continuous sample feature series of the preset time period is constructed according to the discharge pulse duty ratio, discharge pulse number and discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period.

[0041] A trend curve is drawn based on the continuous sample feature series of the preset time period, and whether the corona performance of the generator stator is deteriorated is determined based on the trend curve.

[0042] The second embodiment of the present application provides a generator stator corona degradation monitoring system based on partial discharge, comprising:

[0043] A first acquisition module is used to acquire a multi-fault superimposed global PRPD spectrum of the generator stator at each moment within a preset time period, and mark multiple corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum;

[0044] The second acquisition module is used to acquire the number of discharges at each pulse amplitude and each pulse phase in the positive polarity partial discharge pulse of the generator stator at each moment in the preset time period, and the number of discharges at each pulse amplitude and each pulse phase in the negative polarity partial discharge pulse at each moment in the preset time period based on the multi-fault superposition global PRPD spectrum of the generator stator at each moment in the preset time period;

[0045] The first determination module is used to determine the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period according to each pulse amplitude and the discharge number under each pulse phase in the positive polarity local discharge pulse at each moment in the preset time period, and each pulse amplitude and the discharge number under each pulse phase of the negative polarity local discharge pulse;

[0046] The second determination module is used to determine whether the corona performance of the generator stator is deteriorated according to the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period.

[0047] A third aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect of the present application.

[0048] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0049] The present application proposes a method and system for monitoring corona degradation of a generator stator based on partial discharge, wherein the method comprises: obtaining a multi-fault superimposed global PRPD spectrum of the generator stator at each moment in a preset time period, and marking a plurality of corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum; obtaining the discharge number of each pulse amplitude and each pulse phase in the positive polarity local discharge pulse of the generator stator at each moment in the preset time period, and the discharge number of each pulse of the negative polarity local discharge pulse at each moment in the preset time period based on the multi-fault superimposed global PRPD spectrum of the generator stator at each moment in the preset time period. The discharge pulse duty ratio, discharge pulse number, and discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period are determined according to the pulse amplitude and discharge number under each pulse phase in the positive polarity local discharge pulse at each moment in the preset time period, and the pulse amplitude and discharge number under each pulse phase in the negative polarity local discharge pulse; the corona performance of the generator stator is determined according to the discharge pulse duty ratio, discharge pulse number, and discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period. The technical solution proposed in this application can accurately and effectively monitor the corona state of the original generator insulation local discharge.

[0050] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0052] Figure 1 A flowchart of a method for monitoring corona degradation of a generator stator based on partial discharge according to an embodiment of the present application;

[0053] Figure 2 A multi-fault superimposed global PRPD map provided according to an embodiment of the present application;

[0054] Figure 3 A first schematic diagram of a local spectrum region of corona discharge provided according to an embodiment of the present application;

[0055] Figure 4 A second schematic diagram of a local spectrum region of corona discharge provided according to an embodiment of the present application;

[0056] Figure 5 A B2-QM trend diagram provided according to an embodiment of the present application;

[0057] Figure 6A B2-K trend diagram provided according to an embodiment of the present application;

[0058] Figure 7 The present invention is a structural diagram of a generator stator corona degradation monitoring system based on partial discharge according to an embodiment of the present application. DETAILED DESCRIPTION

[0059] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0060] The present application proposes a method and system for monitoring corona degradation of a generator stator based on partial discharge, wherein the method comprises: obtaining a multi-fault superimposed global PRPD spectrum of the generator stator at each moment in a preset time period, and marking a plurality of corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum; obtaining the pulse amplitudes and the number of discharges under each pulse phase in the positive polarity local discharge pulse of the generator stator at each moment in the preset time period, and the pulses of each negative polarity local discharge pulse at each moment in the preset time period based on the multi-fault superimposed global PRPD spectrum of the generator stator at each moment in the preset time period. The discharge pulse duty ratio, discharge pulse number, and discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period are determined according to the pulse amplitude and discharge number under each pulse phase in the positive polarity local discharge pulse at each moment in the preset time period, and the pulse amplitude and discharge number under each pulse phase in the negative polarity local discharge pulse; the corona performance of the generator stator is determined according to the discharge pulse duty ratio, discharge pulse number, and discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period. The technical solution proposed in this application can accurately and effectively monitor the corona state of the original generator insulation local discharge.

[0061] A method and system for monitoring corona degradation of a generator stator based on partial discharge according to an embodiment of the present application will be described below with reference to the accompanying drawings.

[0062] Embodiment 1

[0063] Figure 1 Flow chart of a method for monitoring stator corona degradation of a generator based on partial discharge according to an embodiment of the present application, as shown in FIG. Figure 1 As shown, the method includes:

[0064] Step 1: Obtain a multi-fault superimposed global PRPD map of the generator stator at each moment in a preset time period, and mark a plurality of corona discharge local map areas in the multi-fault superimposed global PRPD map.

[0065] It should be noted that the multi-fault superposition global PRPD map at a time can be as follows: Figure 2 shown.

[0066] The original data records corresponding to the multi-fault superimposed global PRPD spectrum are shown in Table 1 and Table 2;

[0067] Table 1 Positive polarity partial discharge pulse count

[0068]

[0069] Table 2 Negative polarity partial discharge pulse count

[0070]

[0071]

[0072] It should be noted that the original data Data_d of the multi-fault superimposed global PRPD spectrum is structured and processed, and the pulse recording data corresponding to the spectrum is extracted from the x lsx data table to generate a 32*100*3 3D list data Data;

[0073] 1) The data tables storing pulse records are as follows: Table 1 for positive partial discharge pulse counts, Table 2 for negative partial discharge pulse counts, column indexes 1 to 16 in the table are pulse amplitude windows, the larger the value, the larger the discharge amplitude corresponding to the data in the corresponding column, row indexes 1 to 100 are pulse phases, the larger the value, the larger the discharge phase corresponding to the data in the corresponding row, and the data in the table represent the number of discharges occurring at the current phase and amplitude, i.e., the number of discharges.

[0074] 2) From the negative polarity maximum pane to 0 and then to the positive polarity maximum pane, it is represented by the y coordinate y=[0,1,2......15,16,17......30,31], the phase from 1 to 100 is represented by the x coordinate, x=[0,1,2,3,......97,98,99], and the table data discharge pulse count is represented by z; 269 at the 33rd row and 1st column position in Table 2 can be represented as [32,15,269], 22 at the 100th row and 1st column position in Table 1 can be represented as [99,16,22], 0 at the 80th row and 16th column position in Table 1 can be represented as [79,31,0], and so on, all discharge pulse counts can be represented in the form of [x,y,z] coordinates plus values;

[0075] 3) According to the above 2) method, Data is a 100*32*3 three-dimensional array Data:

[0076] Data=[[[x 00 ,y 00 ,z 00 ],[x 01 ,y 00 ,z 01 ],[x 02 ,y 00 ,z 02 ]......[x 98 ,y 00 ,z 02 ],[x 99 ,y

[0077] 00 ,z 99 ]] .

[0079] [[x 00 ,y 15 ,z 1500 ],[x 01 ,y 15 ,z 1501 ],[x 02 ,y 15 ,z 1502 ]......[x 98 ,y 15 ,z 198 ],[x 99 ,y 15 ,z 1599 ]] .

[0081] [[x 00 ,y 31 ,z 3100 ],[x 01 ,y 31 ,z 3101 ],[x 02 ,y 31 ,z 3102 ]......[x 98 ,y 31 ,z 3198 ],[x 99 ,y 31 ,z 3199 ]]]

[0082] In the embodiment of the present disclosure, the marking of multiple corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum includes:

[0083] Obtain the phase angle ranges when the generator stator discharges;

[0084] Based on the phase angle ranges, a plurality of corona discharge local spectrum regions are marked in the multi-fault superposition global PRPD spectrum at each moment within the preset time period.

[0085] It should be noted that, based on the global spectrum structuring, the corona discharge local spectrum area is determined, such as Figure 3 Middle areas A1, A2, B1, B2. Phase angle θ in area A1 x1 =0,θ x2 =64, phase angle θ in region A2 x1 =324,θ x2 =360, phase angle θ in region B1 x1 =144,θ x2 =180, phase angle θ in region B2 x1 =180,θ x2 =244; the rest of the areas are other types of faults, which have no impact on the development trend analysis of the corona problem. Among them, corona fault is a known typical fault of generator insulation. Through test data statistics, it is found that when a corona fault occurs, the number and position of the dots in the above four selected areas have a strong corresponding relationship, and other areas are weakly correlated or irrelevant. The above areas are determined by the start and end of the phase, and the above areas are represented by three-dimensional data. Figure 3 In the figure, the vertical scale represents the number of panes. The lower half has 16 panes, which are numbered 0-15, and the upper half has 16 panes, which are numbered 16-31, for a total of 32 panes. Corresponding to 32 in the three-dimensional array Data, the array row numbers are 0-31, that is, the panes correspond to the array rows.

[0086] In actual testing, different range units mv will be selected to represent the amplitude of the discharge, that is, the height of the dots in the figure. Different range selections will represent different discharge sizes in each pane, and the dots in the figure will represent different discharge amplitudes. For example, if the range R is selected as: 10-170 [mV], then R = 170, then the lower half 0-15 panes correspond to negative 170-0mv, and the upper half 16-31 correspond to 0-positive 170mv. If the range is increased to 20-340, then the lower half 0-15 panes correspond to negative 340-0mv, and the upper half 16-31 correspond to 0-positive 340mv. That is, the number of panes remains unchanged, and the amplitude represented will change with the range selection, so it can meet the needs of partial discharge tables for faults of different severity on site.

[0087] Step 2: Based on the multi-fault superposition global PRPD map of the generator stator at each moment in a preset time period, the discharge quantity at each pulse amplitude and each pulse phase in the positive polarity partial discharge pulse of the generator stator and the discharge quantity at each pulse amplitude and each pulse phase of the negative polarity partial discharge pulse are obtained at each moment in the preset time period.

[0088] It should be noted that the discharge quantity is the data in Table 1 and Table 2.

[0089] Step 3: Determine the discharge pulse duty ratio, discharge pulse number, and discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period based on the pulse amplitudes of the positive polarity local discharge pulses and the discharge quantity at each pulse phase, and the pulse amplitudes of the negative polarity local discharge pulses and the discharge quantity at each pulse phase.

[0090] In the embodiment of the present disclosure, step 3 specifically includes:

[0091] 3.1 constructing a three-dimensional array at each moment in the preset time period according to each pulse amplitude and the number of discharges at each pulse phase in the positive polarity partial discharge pulse, and each pulse amplitude and the number of discharges at each pulse phase in the negative polarity partial discharge pulse;

[0092] The 3.1 includes:

[0093] Number the pulse amplitudes of the negative polarity partial discharge pulse at the i-th moment to the pulse amplitudes of the positive polarity partial discharge pulse in sequence from zero, and use the pulse amplitude numbers as the y coordinates;

[0094] Numbering each pulse phase in the positive polarity partial discharge pulse and each pulse phase in the negative polarity partial discharge pulse at the i-th moment in sequence from zero, and using each pulse phase as an x-coordinate;

[0095] The pulse amplitudes and discharge numbers under each pulse phase in the positive polarity partial discharge pulse at the i-th moment, and the pulse amplitudes and discharge numbers under each pulse phase in the negative polarity partial discharge pulse are respectively used as the z coordinates under the corresponding pulse amplitudes and pulse phases;

[0096] Constructing a three-dimensional array at the i-th moment based on the y-coordinate, x-coordinate and z-coordinate at the i-th moment;

[0097] Where i belongs to I, and I is the total number of moments in the preset time period.

[0098] For example, the three-dimensional array may be the 100*32*3 three-dimensional array Data constructed in 1) above.

[0099] 3.2 According to the three-dimensional array at each moment in the preset time period, the discharge pulse duty ratio, the discharge pulse number and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period are determined respectively.

[0100] The 3.2 includes:

[0101] 3.2.1 Determine the abscissa and ordinate of the lower left corner and the abscissa and ordinate of the upper right corner of each corona discharge local spectrum region at each moment in the preset time period based on the three-dimensional array at each moment in the preset time period;

[0102] 3.2.2 Determine the first coordinate of the lower left corner and the first coordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period according to the abscissa and ordinate of the lower left corner and the abscissa and ordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period;

[0103] Among them, the above 3.2.2 includes:

[0104] Divide the abscissa of the lower left corner by the preset granularity to obtain the abscissa of the first coordinate of the lower left corner, and use the ordinate of the lower left corner as the ordinate of the first coordinate of the lower left corner;

[0105] The horizontal coordinate of the upper right corner is divided by a preset granularity to obtain the horizontal coordinate of the first coordinate of the upper right corner, and the vertical coordinate of the upper right corner is used as the vertical coordinate of the first coordinate of the upper right corner.

[0106] Among them, in the 100*32*3 three-dimensional array Data, the granularity is equal to

[0107] For example,

[0108] A1: x1=0 / (360 / 100)=0, y1=0; x2=64 / (360 / 100)=18, y2=15;

[0109] A2: x1=324 / (360 / 100)=90, y1=0; x2=360 / (360 / 100)=100, y2=15;

[0110] B1: x1=144 / (360 / 100)=40, y1=16; x2=180 / (360 / 100)=50, y2=31;

[0111] B1: x1=180 / (360 / 100)=50, y1=16; x2=244 / (360 / 100)=68, y2=31;

[0112] Among them, 360 means the phase of a sine wave is 360 degrees. The partial discharge pulse phase analysis PRPD diagram is carried out under a sine wave phase. 100 is 100 in the 100*32*3 three-dimensional array Data, which represents the granularity of the detection record, that is, 360 / 100=3.6 degrees, that is, data is recorded once every 3.6 degrees of phase.

[0113] y1 is the y00 in the 100*32*3 three-dimensional array Data that represents the ordinate value of the lower left corner of the A1 area, that is, the ordinate 0 of the lower left corner of the red frame A1. (The ordinate value 0-31 corresponds to Figure 3 Middle from bottom to top 0-15 16-31 lower half 0-15 upper half 16-31);

[0114] y2 uses y15 in the 100*32*3 three-dimensional array Data to represent the vertical coordinate value of the upper right corner point of the A1 area, that is, the vertical coordinate 15 of the upper right corner of the red frame A1.

[0115] In this way, Figure 3 The starting and ending coordinates of regions A1, A2, B1, B2,4 are recorded in the dictionary regions; taking region A1 as an example, the value corresponding to the A1 key [0,0] represents the coordinates of the lower left corner of region A1, and [18,15] represents the coordinates of the upper right corner of region A1.

[0116] 3.2.3 Obtaining the number of discharges in each corona discharge local spectrum area at each moment within the preset time period;

[0117] 3.2.4 Determine the discharge pulse duty ratio and the number of discharge pulses in the local corona discharge spectrum region according to the number of discharges in the local corona discharge spectrum region, the first coordinate of the lower left corner and the first coordinate of the upper right corner of the local corona discharge spectrum region;

[0118] The calculation formula of the discharge pulse duty ratio in the local spectrum area of ​​the corona discharge is as follows:

[0119] K s =H / ((x2-x1+1)*(y2-y1+1))

[0120] In the formula, K s is the discharge pulse duty ratio in the sth corona discharge local spectrum area, H is the discharge quantity in the sth corona discharge local spectrum area, x1 is the abscissa of the first coordinate in the lower left corner, y1 is the ordinate of the first coordinate in the lower left corner, x2 is the abscissa of the first coordinate in the upper right corner, and y2 is the ordinate of the first coordinate in the upper right corner;

[0121] The calculation formula for the number of discharge pulses in the local spectrum area of ​​the corona discharge is as follows:

[0122]

[0123] Where NQN s is the number of discharge pulses in the sth corona discharge local spectrum area, NQNX s is, z is the number of discharges;

[0124] 3.2.5 Determine the discharge pulse amplitude within the corona discharge local spectrum region according to the first coordinate of the lower left corner and the first coordinate of the upper right corner of the corona discharge local spectrum region.

[0125] The calculation formula of the discharge pulse amplitude in the local spectrum area of ​​the corona discharge is as follows:

[0126]

[0127] In the formula, QM s is the discharge pulse amplitude in the sth corona discharge local spectrum area, R is the upper limit of the range, F is the number of panes of the amplitude, Figure 3 Where F is equal to 32. It should be noted that the upper limit of the R sample test range, such as R: 10-170 [mV], then R = 170.

[0128] Step 4: Determine whether the corona performance of the generator stator is degraded according to the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period.

[0129] In the embodiment of the present disclosure, step 4 specifically includes:

[0130] 4.1: Constructing a continuous sample feature series of the preset time period according to the discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period;

[0131] It should be noted that the continuous sample feature series of the preset time period is X=[X1, X2, .....X n-1 ,X n ], where n is the total number of durations within the preset time period, and the number of samples X at time t within the preset duration n The calculation formula is as follows:

[0132] X n =[[K A1,n , NQN A1,n , QM A1,n ],

[0133] [K A2,n , NQN A2,n , QM A2,n ],

[0134] [K B1,n , NQN B1,n , QM B1,n ],

[0135] [K B2,n , NQN B2,n , QM B2,n ]]

[0136] In the formula, K A1,n NQN is the number of discharge pulses in the local spectrum area of ​​A1 corona discharge at time n, A1,n is the number of discharge pulses in the local spectrum area of ​​A1 corona discharge at time n, QM A1,n is the discharge pulse amplitude in the local spectrum area of ​​A1 corona discharge at time n.

[0137] 4.2: Drawing a trend curve based on the continuous sample feature series of the preset time period, and judging whether the corona performance of the generator stator is deteriorated based on the trend curve.

[0138] It should be noted that, by selecting sample time from the continuous sample feature series X, plotting trend curves for the areas and features to be monitored, a trend graph is obtained. From the trend graph, it can be seen that during many years of continuous operation, the insulation anti-corona performance has been continuously deteriorating.

[0139] In the disclosed embodiment, the A1, A2, B1, and B2 partitions can adjust the size and position of the regions through the coordinate parameters of the corresponding key values ​​in the dictionary regions to meet the monitoring needs of different faults. i =[Ki, NQNi, QMi], i=A1, A2, B1, B2. During trend monitoring, one feature can be monitored, or three can be monitored simultaneously.

[0140] The generator stator corona degradation monitoring method based on partial discharge provided above is described in detail below with reference to an example:

[0141] 1. Obtain the original data of partial discharge samples, as shown in Table 3;

[0142] Table 3

[0143]

[0144] The data in Table 3 is a 100*32*3 three-dimensional list data Data. The sample 7569.xl sx is taken as an example and processed as follows. The other samples are processed in the same way.

[0145] Data=

[0146] [[[0,0,0],[1,0,0],......[98,0,0],[99,0,0]],

[0147] [[0,1,0],[1,1,0],......[98,1,0],[99,1,0]],

[0148] [[0,2,1],[1,2,0],......[98,2,1],[99,2,0]], ......

[0150] [[0,3,0],[1,3,0],......[98,3,0],[99,3,0]],

[0151] [[0,30,0],[1,30,0],.......[98,30,0],[99,30,0]],

[0152] [[0,31,0],[1,31,0],........[98,31,0],[99,31,0]]]

[0153] 2. In the global spectrum structured data, determine the local spectrum area of ​​corona discharge, such as Figure 4 Middle areas A1, A2, B1, B2. Phase angle θ in area A1 x1 =0,θ x2 =64, phase angle θ in region A2 x1 =324,θ x2 =360, phase angle θ in region B1 x1 =144,θ x2 =180, phase angle θ in region B2 x1 =180,θ x2 =244, area selection is as follows Figure 4 As shown in the figure frame.

[0154] 3. Determine the dictionary regions representing the coordinates of the regions A1, A2, B1, and B2 in the atlas, that is, the dictionary regions consisting of the first coordinates;

[0155] 4. Calculate the discharge pulse duty ratios KA1, KA2, KB1, KB2, the number of pulses NQNA1, NQNA2, NQNB1, NQNB2, and the pulse amplitudes QMA1, QMA2, QMB1, QMB2 in the A1, A2, B1, B2 regions. Take ID7569 as an example to calculate the feature quantity, expressed as a three-dimensional array of feature matrix X7569; the feature quantity calculation results are as follows: Figure 4 As shown in the figure frames A1, A2, B1, and B2.

[0156] X7569 =[[11.3,74,42.5],

[0157] [3.1,1,21.2],

[0158] [2.1,1,85],

[0159] [18.8,124,85]]

[0160] According to the above process, the calculation of all samples in Table 3 is completed to obtain the continuous sample data feature series X;

[0161] 5. Select the sample time from the continuous sample feature series X, the area to be monitored, and the feature to draw a trend curve, such as Figure 5 The B2-QM trend graph, Figure 6 The B2-K trend graph shows that the insulation anti-corona performance has been continuously deteriorating during many years of continuous operation.

[0162] The generator stator corona degradation monitoring method based on partial discharge provided in this embodiment mainly relies on online monitoring of partial discharge of insulation. The partial discharge monitoring is for the overall insulation state of the stator winding, including internal insulation defect discharge, internal gap discharge during load cycle, corona discharge, end phase-to-phase gap discharge, metal tip discharge at the conductor connection part, etc. More than one fault occurs at the same time. Therefore, the current online monitoring of partial discharge represents the overall state of multiple faults superimposed, which cannot reflect the specific fault trend. Based on the overall state data of partial discharge, the present invention determines the corona discharge area data, recalculates and extracts features, and monitors the corona discharge through data feature quantities. Solve the problem that the online monitoring of partial discharge of the original generator insulation is not targeted and the corona state monitoring fails. In addition to the corona problem, the insulation defect problem that needs attention can also be detected by adjusting the regional coordinates.

[0163] In summary, the method for monitoring the corona degradation of a generator stator based on partial discharge proposed in this embodiment can accurately and effectively monitor the corona state of the partial discharge of the insulation of the original generator. . . . .

[0164] Embodiment 2

[0165] Figure 7 FIG. 1 is a structural diagram of a generator stator corona degradation monitoring system based on partial discharge according to an embodiment of the present application, such as Figure 7 As shown, the system comprises:

[0166] The first acquisition module 100 is used to acquire a multi-fault superimposed global PRPD spectrum of the generator stator at each moment in a preset time period, and mark multiple corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum;

[0167] Wherein, the marking of multiple corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum includes:

[0168] Obtain the phase angle ranges when the generator stator discharges;

[0169] Based on the phase angle ranges, a plurality of corona discharge local spectrum regions are marked in the multi-fault superposition global PRPD spectrum at each moment within the preset time period.

[0170] The second acquisition module 200 is used to acquire the number of discharges at each pulse amplitude and each pulse phase in the positive polarity partial discharge pulse of the generator stator at each moment in the preset time period, and the number of discharges at each pulse amplitude and each pulse phase in the negative polarity partial discharge pulse at each moment in the preset time period based on the multi-fault superposition global PRPD spectrum of the generator stator at each moment in the preset time period;

[0171] The first determination module 300 is used to determine the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period according to each pulse amplitude and the discharge number under each pulse phase in the positive polarity local discharge pulse, and each pulse amplitude and the discharge number under each pulse phase in the negative polarity local discharge pulse;

[0172] The second determination module 400 is used to determine whether the corona performance of the generator stator is deteriorated according to the discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period.

[0173] In the embodiment of the present disclosure, the first determining module 300 is further configured to:

[0174] Constructing a three-dimensional array at each moment in the preset time period according to each pulse amplitude and the number of discharges at each pulse phase in the positive polarity partial discharge pulse, and each pulse amplitude and the number of discharges at each pulse phase in the negative polarity partial discharge pulse;

[0175] The three-dimensional array at each moment in the preset time period is constructed according to each pulse amplitude and the discharge quantity at each pulse phase in the positive polarity partial discharge pulse at each moment in the preset time period, and each pulse amplitude and the discharge quantity at each pulse phase in the negative polarity partial discharge pulse, including:

[0176] Number the pulse amplitudes of the negative polarity partial discharge pulse at the i-th moment to the pulse amplitudes of the positive polarity partial discharge pulse in sequence from zero, and use the pulse amplitude numbers as the y coordinates;

[0177] Numbering each pulse phase in the positive polarity partial discharge pulse and each pulse phase in the negative polarity partial discharge pulse at the i-th moment in sequence from zero, and using each pulse phase as an x-coordinate;

[0178] The pulse amplitudes and discharge numbers under each pulse phase in the positive polarity partial discharge pulse at the i-th moment, and the pulse amplitudes and discharge numbers under each pulse phase in the negative polarity partial discharge pulse are respectively used as the z coordinates under the corresponding pulse amplitudes and pulse phases;

[0179] Constructing a three-dimensional array at the i-th moment based on the y-coordinate, x-coordinate and z-coordinate at the i-th moment;

[0180] Where i belongs to I, and I is the total number of moments in the preset time period.

[0181] The discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period are determined respectively according to the three-dimensional array at each moment in the preset time period.

[0182] The method of determining the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period according to the three-dimensional array at each moment in the preset time period comprises:

[0183] Determine the abscissa and ordinate of the lower left corner and the abscissa and ordinate of the upper right corner of each corona discharge local spectrum region at each moment in the preset time period based on the three-dimensional array at each moment in the preset time period;

[0184] Determine the first coordinate of the lower left corner and the first coordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period according to the abscissa and ordinate of the lower left corner and the abscissa and ordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period;

[0185] The method of determining the first coordinates of the lower left corner and the first coordinates of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period according to the abscissa and the ordinate of the lower left corner and the abscissa and the ordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period comprises:

[0186] Divide the abscissa of the lower left corner by the preset granularity to obtain the abscissa of the first coordinate of the lower left corner, and use the ordinate of the lower left corner as the ordinate of the first coordinate of the lower left corner;

[0187] The horizontal coordinate of the upper right corner is divided by a preset granularity to obtain the horizontal coordinate of the first coordinate of the upper right corner, and the vertical coordinate of the upper right corner is used as the vertical coordinate of the first coordinate of the upper right corner.

[0188] Obtaining the number of discharges in each corona discharge local spectrum area at each moment in the preset time period;

[0189] Determine the discharge pulse duty ratio and the discharge pulse quantity in the corona discharge local spectrum region according to the discharge quantity in the corona discharge local spectrum region, the first coordinate of the lower left corner and the first coordinate of the upper right corner of the corona discharge local spectrum region;

[0190] The discharge pulse amplitude in the corona discharge local spectrum region is determined according to the first coordinate of the lower left corner and the first coordinate of the upper right corner of the corona discharge local spectrum region.

[0191] The calculation formula of the discharge pulse duty ratio in the local spectrum area of ​​the corona discharge is as follows:

[0192] K s =H / ((x2-x1+1)*(y2-y1+1))

[0193] In the formula, K s is the discharge pulse duty ratio in the sth corona discharge local spectrum area, H is the discharge quantity in the sth corona discharge local spectrum area, x1 is the abscissa of the first coordinate in the lower left corner, y1 is the ordinate of the first coordinate in the lower left corner, x2 is the abscissa of the first coordinate in the upper right corner, and y2 is the ordinate of the first coordinate in the upper right corner;

[0194] The calculation formula for the number of discharge pulses in the local spectrum area of ​​the corona discharge is as follows:

[0195]

[0196] Where NQN s is the number of discharge pulses in the sth corona discharge local spectrum area, NQNX s is, z is the number of discharges;

[0197] The calculation formula of the discharge pulse amplitude in the local spectrum area of ​​the corona discharge is as follows:

[0198]

[0199] In the formula, QM s is the discharge pulse amplitude in the sth corona discharge local spectrum area, R is the upper limit of the range, and F is the number of panes of the amplitude.

[0200] In the embodiment of the present disclosure, the second determining module 400 is further configured to:

[0201] The continuous sample feature series of the preset time period is constructed according to the discharge pulse duty ratio, discharge pulse number and discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period.

[0202] A trend curve is drawn based on the continuous sample feature series of the preset time period, and whether the corona performance of the generator stator is deteriorated is determined based on the trend curve.

[0203] In summary, the generator stator corona degradation monitoring system based on partial discharge proposed in this embodiment can accurately and effectively monitor the corona state of partial discharge of the original generator insulation.

[0204] Embodiment 3

[0205] In order to implement the above embodiments, the present disclosure further proposes a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method described in the first embodiment is implemented.

[0206] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0207] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0208] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for monitoring the corona degradation of a generator stator based on partial discharge, characterized in that: The method comprises: Obtaining a multi-fault superimposed global PRPD spectrum of the generator stator at each moment within a preset time period, and marking a plurality of corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum; Based on the multi-fault superposition global PRPD spectrum of the generator stator at each moment in a preset time period, the number of discharges at each pulse amplitude and each pulse phase in the positive polarity partial discharge pulse of the generator stator and the number of discharges at each pulse amplitude and each pulse phase in the negative polarity partial discharge pulse are obtained; Determine the discharge pulse duty ratio, discharge pulse number, and discharge pulse amplitude in each corona discharge local spectrum region at each moment in the preset time period according to each pulse amplitude and the discharge number at each pulse phase in the positive polarity local discharge pulse, and each pulse amplitude and the discharge number at each pulse phase in the negative polarity local discharge pulse; Whether the corona performance of the generator stator is deteriorated is determined according to the discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period.

2. The method according to claim 1, characterized in that The method of marking a plurality of corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum includes: Obtain the phase angle ranges when the generator stator discharges; Based on the phase angle ranges, a plurality of corona discharge local spectrum regions are marked in the multi-fault superposition global PRPD spectrum at each moment within the preset time period.

3. The method according to claim 2, characterized in that The method of determining the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period according to each pulse amplitude and the discharge number at each pulse phase in the positive polarity local discharge pulse and the discharge number at each pulse phase in the negative polarity local discharge pulse at each moment in the preset time period comprises: Constructing a three-dimensional array at each moment in the preset time period according to each pulse amplitude and the number of discharges at each pulse phase in the positive polarity partial discharge pulse, and each pulse amplitude and the number of discharges at each pulse phase in the negative polarity partial discharge pulse; The discharge pulse duty ratio, the number of discharge pulses and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period are determined respectively according to the three-dimensional array at each moment in the preset time period.

4. The method according to claim 3, characterized in that The three-dimensional array at each moment in the preset time period is constructed according to each pulse amplitude and the discharge quantity at each pulse phase in the positive polarity partial discharge pulse at each moment in the preset time period, and each pulse amplitude and the discharge quantity at each pulse phase in the negative polarity partial discharge pulse, including: Number the pulse amplitudes of the negative polarity partial discharge pulse at the i-th moment to the pulse amplitudes of the positive polarity partial discharge pulse in sequence from zero, and use the pulse amplitude numbers as the y coordinates; Numbering each pulse phase in the positive polarity partial discharge pulse and each pulse phase in the negative polarity partial discharge pulse at the i-th moment in sequence from zero, and using each pulse phase as an x-coordinate; The pulse amplitudes and discharge numbers under each pulse phase in the positive polarity partial discharge pulse at the i-th moment, and the pulse amplitudes and discharge numbers under each pulse phase in the negative polarity partial discharge pulse are respectively used as the z coordinates under the corresponding pulse amplitudes and pulse phases; Constructing a three-dimensional array at the i-th moment based on the y-coordinate, x-coordinate and z-coordinate at the i-th moment; Where i belongs to I, and I is the total number of moments in the preset time period.

5. The method according to claim 4, characterized in that The method of determining the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period according to the three-dimensional array at each moment in the preset time period comprises: Determine the abscissa and ordinate of the lower left corner and the abscissa and ordinate of the upper right corner of each corona discharge local spectrum region at each moment in the preset time period based on the three-dimensional array at each moment in the preset time period; Determine the first coordinate of the lower left corner and the first coordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period according to the abscissa and ordinate of the lower left corner and the abscissa and ordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period; Obtaining the number of discharges in each corona discharge local spectrum area at each moment in the preset time period; Determine the discharge pulse duty ratio and the discharge pulse quantity in the corona discharge local spectrum region according to the discharge quantity in the corona discharge local spectrum region, the first coordinate of the lower left corner and the first coordinate of the upper right corner of the corona discharge local spectrum region; The discharge pulse amplitude in the corona discharge local spectrum area is determined according to the first coordinate of the lower left corner and the first coordinate of the upper right corner of the corona discharge local spectrum area.

6. The method according to claim 5, characterized in that The method of determining the first coordinates of the lower left corner and the first coordinates of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period according to the abscissa and the ordinate of the lower left corner and the abscissa and the ordinate of the upper right corner of each corona discharge local spectrum area at each moment in the preset time period comprises: Divide the abscissa of the lower left corner by the preset granularity to obtain the abscissa of the first coordinate of the lower left corner, and use the ordinate of the lower left corner as the ordinate of the first coordinate of the lower left corner; The horizontal coordinate of the upper right corner is divided by a preset granularity to obtain the horizontal coordinate of the first coordinate of the upper right corner, and the vertical coordinate of the upper right corner is used as the vertical coordinate of the first coordinate of the upper right corner.

7. The method according to claim 5, characterized in that The calculation formula of the discharge pulse duty ratio in the local spectrum area of ​​the corona discharge is as follows: K s =H / ((x2-x1+1)*(y2-y1+1)) In the formula, K s is the discharge pulse duty ratio in the sth corona discharge local spectrum area, H is the discharge quantity in the sth corona discharge local spectrum area, x1 is the abscissa of the first coordinate in the lower left corner, y1 is the ordinate of the first coordinate in the lower left corner, x2 is the abscissa of the first coordinate in the upper right corner, and y2 is the ordinate of the first coordinate in the upper right corner; The calculation formula for the number of discharge pulses in the local spectrum area of ​​the corona discharge is as follows: Where NQN s is the number of discharge pulses in the sth corona discharge local spectrum area, NQNX s is, z is the number of discharges; The calculation formula of the discharge pulse amplitude in the local spectrum area of ​​the corona discharge is as follows: In the formula, QM s is the discharge pulse amplitude in the sth corona discharge local spectrum area, R is the upper limit of the range, and F is the number of panes of the amplitude.

8. The method according to claim 7, characterized in that The method of determining whether the corona performance of the generator stator is deteriorated according to the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period includes: The continuous sample feature series of the preset time period is constructed according to the discharge pulse duty ratio, discharge pulse number and discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period. A trend curve is drawn based on the continuous sample feature series of the preset time period, and whether the corona performance of the generator stator is deteriorated is determined based on the trend curve.

9. A generator stator corona degradation monitoring system based on partial discharge, characterized in that: The system comprises: A first acquisition module is used to acquire a multi-fault superimposed global PRPD spectrum of the generator stator at each moment within a preset time period, and mark multiple corona discharge local spectrum areas in the multi-fault superimposed global PRPD spectrum; The second acquisition module is used to acquire the number of discharges at each pulse amplitude and each pulse phase in the positive polarity partial discharge pulse of the generator stator at each moment in the preset time period, and the number of discharges at each pulse amplitude and each pulse phase in the negative polarity partial discharge pulse at each moment in the preset time period based on the multi-fault superposition global PRPD spectrum of the generator stator at each moment in the preset time period; The first determination module is used to determine the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period according to each pulse amplitude and the discharge number under each pulse phase in the positive polarity local discharge pulse at each moment in the preset time period, and each pulse amplitude and the discharge number under each pulse phase of the negative polarity local discharge pulse; The second determination module is used to determine whether the corona performance of the generator stator is deteriorated according to the discharge pulse duty ratio, the number of discharge pulses, and the discharge pulse amplitude in each corona discharge local spectrum area at each moment in the preset time period.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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