A high altitude power equipment condition monitoring system and method

Abstract

The application discloses a kind of high-altitude electric power equipment condition monitoring system and method, it is related to data analysis field, main scheme is: according to photovoltaic power generation-energy storage system cooperation efficiency index WA, transmission line stability index WB, photovoltaic power generation-inversion cooperation index WC, photovoltaic power generation system index WD and energy storage system state index WE calculate electric power equipment operating state index X, according to electric power equipment operating state index X and operating state threshold set determine electric power equipment operating state, solved the traditional monitoring system often only pay attention to the operating state of single equipment, neglect the cooperative working relationship between different equipment and each system, leading to unable comprehensive evaluation the operating condition of entire light storage project, difficult and timely discover systemic potential problem problem.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data analysis, in particular to a high-altitude power equipment condition monitoring system and method. BACKGROUND

[0002] In the super-high altitude area, the environmental conditions are harsh, such as low temperature, low air pressure, strong ultraviolet light and other factors have a greater impact on the light storage equipment. By using the high-altitude power equipment condition monitoring method to monitor the super-high altitude light storage project, the running data of the equipment can be obtained in real time, which is beneficial to find potential faults in advance, enhance the safety of the system, and reduce the operation and maintenance cost and difficulty.

[0003] The traditional monitoring of the condition of high-altitude power equipment is mainly through the installation of sensors on the power equipment to collect the running parameters of the equipment, such as temperature, voltage, current, etc. The system pre-sets the normal working threshold range of each parameter, and when the collected parameter exceeds this range, an alarm will be triggered.

[0004] The existing technology still has the following shortcomings: the traditional monitoring system often only focuses on the running state of a single device, ignores the cooperative working relationship between different devices and various systems, and leads to the inability to comprehensively evaluate the running condition of the entire light storage project, and the difficulty in discovering potential problems in a timely manner. SUMMARY

[0005] (I) Technical problems solved

[0006] In view of the deficiencies of the prior art, the present application provides a high-altitude power equipment condition monitoring system and method, which calculates the power equipment running state index X according to the photovoltaic power generation-energy storage system synergy efficiency index WA, the power transmission line stability index WB, the photovoltaic power generation-inverter synergy index WC, the photovoltaic power generation system index WD and the energy storage system state index WE, and judges the power equipment running state according to the power equipment running state index X and the running state threshold set, which solves the problem that the traditional monitoring system often only focuses on the running state of a single device, ignores the cooperative working relationship between different devices and various systems, and leads to the inability to comprehensively evaluate the running condition of the entire light storage project, and the difficulty in discovering potential problems in a timely manner.

[0007] (II) Technical solutions

[0008] In order to achieve the above purpose, the present application is realized by the following technical solutions: a high-altitude power equipment condition monitoring method, comprising the following steps:

[0009] Collecting photovoltaic power generation system data, energy storage system data, overall data, inverter and grid-connected system data and power transmission line data of the light storage project;

[0010] The photovoltaic power generation-energy storage system coordination efficiency index WA is calculated based on photovoltaic power generation system data, energy storage system data and overall data; the power transmission line stability index WB is calculated based on inverter and grid connection system data and power transmission line data; the power transmission consistency index QA is calculated based on inverter and grid connection system data, and the photovoltaic power generation-inverter coordination index WC is calculated according to the power transmission consistency index QA, photovoltaic power generation system data and inverter and grid connection system data; the photovoltaic power generation system index WD is calculated based on photovoltaic power generation system data; the energy storage system state index WE is calculated based on energy storage system data; and the power equipment operation state index X is calculated according to the photovoltaic power generation-energy storage system coordination efficiency index WA, the power transmission line stability index WB, the photovoltaic power generation-inverter coordination index WC, the photovoltaic power generation system index WD and the energy storage system state index WE;

[0011] A set of preset operation state thresholds is set; the power equipment operation state is determined according to the power equipment operation state index X and the set of operation state thresholds, and a pre-warning method is selected according to the power equipment operation state.

[0012] In the preferred scheme of the high-altitude power equipment condition monitoring method, the method for calculating the photovoltaic power generation-energy storage system coordination efficiency index WA is as follows:

[0013] The photovoltaic power generation system data includes photovoltaic module output power AA a and photovoltaic module power change start time AE;

[0014] The energy storage system data includes energy storage system charging and discharging power AB a and energy storage system start response time AF;

[0015] The overall data includes useful power AC a that meets the load demand.

[0016] The photovoltaic power generation-energy storage system coordination efficiency index WA is calculated according to the photovoltaic power generation system data, the energy storage system data and the overall data, and the formula is as follows:

[0017]

[0018] Wherein, AA a is the output power of the photovoltaic module at the a-th sampling time point, a is the serial number corresponding to different sampling time points, and the value is [1, b]; b is the total number of sampling time points, and the value is a positive integer; AB a is the charging or discharging power of the energy storage system at the a-th sampling time point; and AC a is the useful power that meets the load demand at the a-th sampling time point.

[0019] In the preferred scheme of the high-altitude power equipment condition monitoring method: the method for calculating the power transmission consistency index QA is:

[0020] The inverter and grid-connected system data includes the effective value of the harmonic current BA of the inverter d , the effective value of the fundamental wave current BB, and the rated effective value of the output current BD.

[0021] The power transmission line data includes the power transmission line resistance CA and the power transmission line reactance CB.

[0022] The power transmission line stability index WB is calculated according to the inverter and grid-connected system data and the power transmission line data, and the formula is:

[0023]

[0024] Among them, BA d is the effective value of the dth harmonic harmonic current, d is the serial number corresponding to different harmonic waves, and the value is [1, f]; f is the total number of harmonics, and the value is a positive integer.

[0025] In the preferred scheme of the high-altitude power equipment condition monitoring method: the method for calculating the power transmission consistency index QA is:

[0026] The inverter and grid-connected system data further includes the inverter input power DA a and the inverter output power DB a .

[0027] The power transmission consistency index QA is calculated according to the inverter input power DA a and the inverter output power DB a , and the formula is:

[0028]

[0029] Among them, DA a is the input power of the inverter at the ath sampling time point; DB a is the output power of the inverter at the ath sampling time point.

[0030] In the preferred scheme of the high-altitude power equipment condition monitoring method: the method for calculating the light-photovoltaic power generation-inversion coordination index WC is:

[0031] The photovoltaic power generation system data further includes the output voltage frequency EA.

[0032] The inverter and grid-connected system data further includes the grid frequency EB, the grid rated frequency EC, the inverter conversion efficiency ED, and the inverter conversion efficiency average EE.

[0033] The photovoltaic power generation-inverter coordination index WC is calculated according to the power transmission consistency index QA, the output voltage frequency EA, the grid frequency EB, the grid rated frequency EC, the inverter conversion efficiency ED and the inverter conversion efficiency average EE, and the formula is:

[0034]

[0035] Wherein, ɑ1 is the weight coefficient of the power transmission consistency index QA, and the value is 0.3-0.5; ɑ2 is the weight coefficient of , and the value is 0.2-0.5; ɑ3 is the weight coefficient of , and the value is 0.2-0.5; and ɑ1+ɑ2+ɑ3=1.

[0036] In the preferred scheme of the above-mentioned high-altitude power equipment condition monitoring method: the method for calculating the photovoltaic power generation system index WD is:

[0037] The photovoltaic power generation system data further includes the DC cabinet branch output voltage FA i , the branch output voltage average FB, the branch output current FC i , the branch output current average FD and the photovoltaic module rated power FE.

[0038] The photovoltaic power generation system index WD is calculated according to the DC cabinet branch output voltage FA i , the branch output voltage average FB, the branch output current FC i , the branch output current average FD, the photovoltaic module output power AA a and the photovoltaic module rated power FE, and the formula is:

[0039]

[0040] Wherein, FA i is the output voltage of the i-th branch in the DC cabinet, i is the serial number corresponding to different branches, and the value is [1, m]; m is the total number of branches in the DC cabinet, and the value is a positive integer; FC i is the output current of the i-th branch in the DC cabinet.

[0041] In the preferred scheme of the above-mentioned high-altitude power equipment condition monitoring method: the method for calculating the energy storage system state index WE is:

[0042] The energy storage system data further includes the initial state of charge GA, the battery pack rated capacity GB, the battery pack charge and discharge current GC(t), the battery pack initial internal resistance GD and the battery pack current internal resistance GE.

[0043] The energy storage system state index WE is calculated according to the initial charge state GA, the battery pack rated capacity GB, the battery pack charging and discharging current GC(t), the battery pack initial internal resistance GD and the battery pack current internal resistance GE, and the formula is:

[0044]

[0045] Wherein, GC(t) is the battery pack charging and discharging current at time point t, t is the serial number corresponding to different time points, t1 is the time length of the detection period.

[0046] In the preferred scheme of the high-altitude power equipment condition monitoring method, the method for calculating the power equipment operation state index X is:

[0047] The power equipment operation state index X is calculated according to the photovoltaic power generation-energy storage system collaborative efficiency index WA, the power transmission line stability index WB, the photovoltaic power generation-inverter collaborative index WC, the photovoltaic power generation system index WD and the energy storage system state index WE,

[0048] The formula is:

[0049]

[0050] In the preferred scheme of the high-altitude power equipment condition monitoring method, the method for judging the power equipment operation state is:

[0051] The operation state threshold set includes a normal operation state threshold YC, a medium risk threshold YZ and a high risk threshold YG;

[0052] The power equipment operation state is judged according to the power equipment operation state index X and the operation state threshold set, and the standard is:

[0053]

[0054] When it is the normal operation state, the first warning mode is selected;

[0055] When it is the low-risk operation state, the second warning mode is selected;

[0056] When it is the medium-risk operation state, the third warning mode is selected;

[0057] When it is the high-risk operation state, the fourth warning mode is selected.

[0058] The application further discloses a high-altitude power equipment condition monitoring system, which comprises:

[0059] The data acquisition module is used for acquiring photovoltaic power generation system data, energy storage system data, overall data, inverter and grid-connected system data and power transmission line data of the light and storage project.

[0060] The index calculation module is capable of calculating a photovoltaic power generation-energy storage system coordination efficiency index WA based on photovoltaic power generation system data, energy storage system data and overall data; calculating a power transmission line stability index WB based on inverter and grid-connected system data and power transmission line data; calculating a power transmission consistency index QA based on inverter and grid-connected system data; calculating a photovoltaic power generation-inverter coordination index WC according to the power transmission consistency index QA, photovoltaic power generation system data and inverter and grid-connected system data; calculating a photovoltaic power generation system index WD based on photovoltaic power generation system data; calculating an energy storage system state index WE based on energy storage system data; and calculating a power equipment operation state index X according to the photovoltaic power generation-energy storage system coordination efficiency index WA, the power transmission line stability index WB, the photovoltaic power generation-inverter coordination index WC, the photovoltaic power generation system index WD and the energy storage system state index WE;

[0061] The judgment module is capable of presetting a set of operation state threshold values; judging the operation state of the power equipment according to the power equipment operation state index X and the set of operation state threshold values; and selecting a warning method according to the operation state of the power equipment.

[0062] (Three) beneficial effects

[0063] The application provides a high-altitude power equipment condition monitoring system and method, which has the following beneficial effects:

[0064] (1) By collecting photovoltaic power generation system data, energy storage system data, overall data, inverter and grid-connected system data and power transmission line data of the light storage project, the operation state of the light storage project can be evaluated from multiple dimensions, and the accuracy of the evaluation can be improved.

[0065] (2) The photovoltaic power generation-energy storage system coordination efficiency index WA is calculated based on photovoltaic power generation system data, energy storage system data and overall data, which can accurately measure the coordination of the photovoltaic power generation system and the energy storage system in actual operation, help to determine the optimal configuration ratio of the photovoltaic power generation system and the energy storage system, the power transmission line stability index WB is calculated based on inverter and grid-connected system data and power transmission line data, which not only reflects the condition of the power transmission line itself, but also reflects the influence of the inverter and grid-connected system on the stability of power transmission, comprehensively grasps various factors in the power transmission process, helps to find potential weak links of the system, the photovoltaic power generation-inverter coordination index WC is calculated based on photovoltaic power generation system data and inverter and grid-connected system data, which comprehensively considers the data of the two key links of photovoltaic power generation and inverter grid connection, can comprehensively evaluate the efficiency of the entire power generation and grid connection process, and intuitively show whether the two can work efficiently under different working conditions, providing a key reference for evaluating the overall performance of the system, the photovoltaic power generation system index WD is calculated based on photovoltaic power generation system data, which can reflect the running state of the photovoltaic power generation system in real time, understand the power generation level of the system under different light conditions, and evaluate whether it meets the design requirements and expected goals, the energy storage system state index WE is calculated based on energy storage system data, which can understand the energy storage level of the energy storage system and the loss in the energy conversion process, and provide a reference for optimizing system operation, the power equipment running state index X is calculated according to the photovoltaic power generation-energy storage system coordination efficiency index WA, the power transmission line stability index WB, the photovoltaic power generation-inverter coordination index WC, the photovoltaic power generation system index WD and the energy storage system state index WE, which is conducive to the comprehensive analysis of the overall running state of the equipment, avoids the misjudgment or omission caused by single index judgment, solves the problem that the traditional monitoring system often only pays attention to the running state of a single device, ignores the cooperative working relationship between different devices and systems, and cannot comprehensively evaluate the running state of the entire photovoltaic storage project, and cannot find potential problems in the system in time.

[0066] (3) The power equipment running state is judged according to the power equipment running state index X and the running state threshold set, which can reflect the equipment condition in real time and provide accurate equipment running information for the operation and maintenance personnel, and the warning method is selected according to the power equipment running state, which is conducive to finding potential problems and hidden troubles of the equipment in advance, avoiding the occurrence of equipment failure, and ensuring the stable operation of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 It is a working step schematic diagram of the high-altitude power equipment condition monitoring method. DETAILED DESCRIPTION

[0068] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work are within the protection scope of the present application.

[0069] Please refer to Figure 1 The present application provides a high-altitude power equipment condition monitoring method, comprising the following steps:

[0070] Step 1: Collecting photovoltaic power generation system data, energy storage system data, overall data, inverter and grid-connected system data and power transmission line data of the light storage project.

[0071] In combination with the content of step 1:

[0072] By collecting photovoltaic power generation system data, energy storage system data, overall data, inverter and grid-connected system data and power transmission line data of the light storage project, the running state of the light storage project can be evaluated from multiple dimensions, which is conducive to improving the accuracy of evaluation.

[0073] Step 2: Calculating photovoltaic power generation-energy storage system coordination efficiency index WA based on photovoltaic power generation system data, energy storage system data and overall data; calculating power transmission line stability index WB based on inverter and grid-connected system data and power transmission line data; calculating power transmission consistency index QA based on inverter and grid-connected system data; calculating photovoltaic power generation-inverter coordination index WC according to power transmission consistency index QA, photovoltaic power generation system data and inverter and grid-connected system data; calculating photovoltaic power generation system index WD based on photovoltaic power generation system data; calculating energy storage system state index WE based on energy storage system data; and calculating power equipment running state index X according to photovoltaic power generation-energy storage system coordination efficiency index WA, power transmission line stability index WB, photovoltaic power generation-inverter coordination index WC, photovoltaic power generation system index WD and energy storage system state index WE.

[0074] Step 2 comprises the following steps:

[0075] Step 201: The method for calculating photovoltaic power generation-energy storage system coordination efficiency index WA is:

[0076] The photovoltaic power generation system data comprises photovoltaic module output power AA a and photovoltaic module power change start time AE.

[0077] It should be noted that when monitoring and analyzing the photovoltaic power generation system, the output power data of the photovoltaic module needs to be collected at multiple sampling time points, which can be equally spaced time points, for example, power data is collected every 1 minute, 5 minutes or 10 minutes. The output power AA a of the photovoltaic module refers to the size of the electric power converted from solar energy to electric energy and output by the photovoltaic module at a certain sampling time point, which reflects the power generation capacity under the comprehensive action of factors such as light intensity, temperature, module performance at that time, and the unit is watt. It is measured and obtained by installing a high-precision power sensor at the output end of the photovoltaic module. The power change start time AE of the photovoltaic module refers to the time point at which the output power of the photovoltaic module begins to change significantly. The acquisition method is to calculate the difference value of power between adjacent two sampling time points. When the difference value is greater than 5% of the rated power of the photovoltaic module, it is considered that the power begins to change significantly. The time point corresponding to the latter sampling time point in the difference calculation is the power change start time AE of the photovoltaic module.

[0078] The energy storage system data includes the energy storage system charge and discharge power AB a and the energy storage system start response time AF.

[0079] It should be noted that the energy storage system charge and discharge power AB a refers to the power size of the energy storage system releasing electric energy to the outside or absorbing electric energy from the outside at a certain time. When discharging, the power value is positive, indicating that the energy storage system supplies power to the outside as a power supply. When charging, the power value is negative, indicating that the energy storage system obtains electric energy from the outside as a load. It is a key indicator for measuring the working state and energy throughput capacity of the energy storage system. The unit is watt, which is measured and obtained by installing a power sensor at the input and output end of the energy storage system. The energy storage system start response time AF refers to the time point at which the energy storage system begins to adjust its charge and discharge power to respond when the output power of the photovoltaic power generation system changes. The acquisition method is to set a signal trigger detection mechanism in the control signal line or power regulation device of the energy storage system. When a signal is received that needs to change the charge and discharge power due to the change of the output power of the photovoltaic module, the receiving time of this signal is recorded as the energy storage system start response time AF.

[0080] The overall data includes the useful power AC a that meets the load demand.

[0081] It should be noted that the useful power AC aAC power refers to the power jointly provided by the photovoltaic power generation system and the energy storage system to the load, which can be effectively utilized by the load to complete its expected function. The unit is watts. It is obtained by installing power sensors at the input ports of each load and accumulating the power values ​​measured at the same sampling time point as the usable power (AC) to meet the load demand. a .

[0082] The photovoltaic power generation-energy storage system synergistic efficiency index WA is calculated based on photovoltaic power generation system data, energy storage system data, and overall data. The formula used is as follows:

[0083]

[0084] Among them, AA a Let AB represent the output power of the photovoltaic module at the a-th sampling time point, where a is the sequence number corresponding to different sampling time points, taking the value [1, b]; b is the total number of sampling time points, taking the value as a positive integer; a The charging or discharging power of the energy storage system at the a-th sampling time point; AC a This represents the useful power required to meet the load demand at the a-th sampling time point.

[0085] It should be noted that the operating principle of this formula is as follows: This represents the cumulative effective power actually provided by the system to the load at various times, reflecting the portion of the system's output power that is truly utilized by the load. The sum of the absolute values ​​of the power generated by the photovoltaic module and the charging and discharging power of the energy storage system represents the system's potential energy supply capacity. The proportion of power that is effectively utilized relative to the total input power reflects the system's efficiency in energy supply utilization. A higher proportion indicates that the system can more effectively convert its potential energy supply into actual power useful to the load, demonstrating better performance in energy utilization and coordination. The response speed of the energy storage system to changes in the power of photovoltaic modules is measured by calculating the time interval between power changes and the response of the energy storage system. The shorter the time interval, the faster the response speed and the better the synergistic effect. This formula obtains the photovoltaic power generation-energy storage system synergistic efficiency index WA by multiplying the two indicators and taking into account the influence of the two indicators.

[0086] Step 202: The method for calculating the transmission line stability index WB is as follows:

[0087] Inverter and grid-connected system data includes the RMS value of the inverter's harmonic current (BA). d The fundamental current RMS value BB and the rated RMS value of the output current BD.

[0088] It should be noted that the effective value of harmonic current BA dis the effective value of the current of the frequency component other than the fundamental frequency in the inverter output current, the effective value of the fundamental current BB is the effective value of the sinusoidal current with the same frequency as the grid frequency in the inverter output current, which is the main component of the inverter output current and determines the size of the active power provided by the inverter to the load, the effective value of the harmonic current BA d and the effective value of the fundamental current BB are measured using a power quality analyzer, with the unit being amperes, and the rated effective value of the output current BD is the effective value of the current that the inverter can stably output under the condition of rated input voltage and rated power, which can be obtained by checking the inverter nameplate or technical specifications, with the unit being amperes.

[0089] The transmission line data includes the transmission line resistance CA and the transmission line reactance CB.

[0090] It should be noted that the transmission line resistance CA refers to the characteristic of hindering the flow of current due to the resistivity of the material of the line conductor, as well as the cross-sectional area and length of the conductor, which causes the conversion of electrical energy into heat energy, with the unit being ohms, and the method of obtaining is to measure the resistance at different positions on the transmission line using a multimeter, and then accumulate the measured resistance data and divide by the number of data to obtain the transmission line resistance CA. The transmission line reactance CB is the hindering effect of the current on the current due to the magnetic field generated by the current around the transmission line, as well as the self-induction and mutual induction effects of alternating current in the conductor, with the unit being ohms, and the method of obtaining is to measure the reactance at different positions on the transmission line using an impedance analyzer, and then accumulate the measured reactance data and divide by the number of data to obtain the transmission line reactance CB.

[0091] The transmission line stability index WB is calculated according to the inverter and grid-connected system data and the transmission line data, and the formula used is:

[0092]

[0093] where BA d is the effective value of the dth harmonic current, d is the serial number corresponding to different harmonics, and the value is [1, f]; f is the total number of harmonics, and the value is a positive integer.

[0094] It should be noted that the running principle of the formula is: is a constant related to the characteristics of three-phase circuits, which is used to consider the phase relationship and power transmission characteristics of three-phase systems, For the impedance of the transmission line, the greater the impedance, the stronger the hindering effect on the current, and the greater the impact on the stability of the transmission line. The output current rated effective value BD represents the maximum current capacity that the inverter can output. The greater this value, the greater the current that the inverter can provide, the greater the voltage drop and power loss on the transmission line, and the greater the impact on the stability of the transmission line. is the ratio of harmonic current to fundamental current, which can reflect the harmonic distortion degree of the inverter output current. The higher the harmonic distortion degree, the greater the impact on the stability of the transmission line. The formula quantitatively evaluates the stability of the transmission line by comprehensively considering the inverter and grid-connected system data and the transmission line data, and obtains the transmission line stability index WB.

[0095] Step 203: The method for calculating the power transmission consistency index QA is:

[0096] The inverter and grid-connected system data also includes the inverter input power DA a and the inverter output power DB a .

[0097] It should be noted that the inverter input power DA a is the power provided to the inverter, which is the energy source for the operation of the inverter. The size of the input power determines the upper limit of the AC power that the inverter can output, and also reflects the power supply capacity of the DC power supply. The inverter output power DB a is the power output by the inverter after converting the input DC power into AC power, which is the actual power provided by the inverter to the AC load. The size and stability of the output power directly affect the normal operation of the load. The inverter input power DA a and the inverter output power DB a are measured and obtained by connecting a power sensor in series between the DC power supply and the input terminal of the inverter, with the unit being watts.

[0098] The power transmission consistency index QA is calculated according to the inverter input power DA a and the inverter output power DB a , and the formula is:

[0099]

[0100] where DA a is the input power of the inverter at the a-th sampling time point; and DB a is the output power of the inverter at the a-th sampling time point.

[0101] It should be noted that the operation principle of the formula is that the numerator part is the sum of the input power and the output power at each sampling time point, which is a measure of the degree of association between the input power and the output power at each sampling time. If the input power and the output power are both large at a certain sampling time point, their product is also large, and the contribution to the numerator is large. Conversely, if one of them is small, the product is small, and the contribution to the numerator is also small. By summing the products of all sampling time points, the total sum of the degree of association between the input power and the output power in the entire sampling time period is obtained. The denominator part is the normalization processing of the overall scale of the input power and the output power. The formula evaluates the cooperative relationship between the energy storage system state of charge and the inverter output power by calculating the correlation between them. The stronger the correlation, the higher the degree of association between the input power and the output power of the inverter at each sampling time point, the better the consistency of power transmission, and the higher the power transmission consistency index QA.

[0102] Step 204: The method for calculating the photovoltaic power generation-inverter cooperation index WC is:

[0103] The photovoltaic power generation system data further includes an output voltage frequency EA.

[0104] It should be noted that the output voltage frequency EA refers to the number of times the output alternating voltage periodically changes per second after the inverter converts the direct current generated by the solar panel into alternating current, with the unit being hertz, which is measured and obtained using a frequency meter.

[0105] The inverter and grid-connected system data further includes a grid frequency EB, a grid rated frequency EC, an inverter conversion efficiency ED, and an inverter conversion efficiency average EE.

[0106] It should be noted that the grid frequency EB refers to the frequency of alternating current in the grid, which is one of the important indicators for measuring power quality, with a unit of hertz, measured by using a frequency meter, specifically: connecting the voltage input end of the frequency meter to the AC bus of the grid, the frequency meter will automatically detect and display the grid frequency value, which is the grid frequency EB, the grid rated frequency EC refers to the standard frequency value according to which the grid is designed and operated, in China, the grid rated frequency is 50Hz, the inverter conversion efficiency ED refers to the efficiency of the inverter in converting input DC power into output AC power, which is one of the important indicators for measuring the performance of the inverter, the method for obtaining is: using a power analyzer to measure the input DC power and output AC power of the inverter respectively, and calculating the inverter conversion efficiency ED according to the formula (inverter output power / inverter input power) x 100%, the average value EE of the inverter conversion efficiency refers to the average value of the inverter conversion efficiency in a period of time, which is a comprehensive evaluation of the conversion efficiency of the inverter under different working conditions, the method for obtaining is: using a power analyzer to measure the input DC power and output AC power of the inverter multiple times in a unit of time, such as a day, a week, a month, and calculating the inverter conversion efficiency according to the formula (inverter output power / inverter input power) x 100%, then adding all the measured conversion efficiency values in the unit of time, and dividing by the number of measurements, to obtain the average value EE of the inverter conversion efficiency.

[0107] According to the power transmission consistency index QA, the output voltage frequency EA, the grid frequency EB, the grid rated frequency EC, the inverter conversion efficiency ED and the average value EE of the inverter conversion efficiency, the photovoltaic power generation-inverter coordination index WC is calculated, and the formula is:

[0108]

[0109] Wherein, ɑ1 is the weight coefficient of the power transmission consistency index QA, the value is 0.3-0.5, which is determined according to the importance of the power transmission consistency index QA to the photovoltaic power generation-inverter coordination index WC; ɑ2 is the weight coefficient of , the value is 0.2-0.5, which is determined according to the importance of to the photovoltaic power generation-inverter coordination index WC; ɑ3 is the weight coefficient of , the value is 0.2-0.5, which is determined according to the importance of to the photovoltaic power generation-inverter coordination index WC; and ɑ1+ɑ2+ɑ3=1.

[0110] It should be noted that the operating principle of the formula is: when operating in parallel, the AC frequency output by the photovoltaic power generation system needs to be synchronized with the grid frequency, is the absolute value of the difference between the output voltage frequency and the grid frequency and the relative proportion of the grid rated frequency, represents the relative ratio, which is inversely proportional to the final index, The smaller, the higher the output voltage frequency and grid matching, The greater, the higher the output voltage and grid frequency matching, the greater the contribution to the final index, represents the ratio of the current inverter conversion efficiency to the average conversion efficiency, the greater the ratio, the higher the stability of the efficiency conversion, which means that the photovoltaic power generation system and the inverter and grid-connected system are more stable in the process of electric energy conversion. This formula obtains the photovoltaic power generation-inverter coordination index WC by weighting and summing the power transmission consistency, frequency synchronization coordination and inverter conversion efficiency.

[0111] Step 205: The method for calculating the photovoltaic power generation system index WD is:

[0112] The photovoltaic power generation system data also includes the DC cabinet branch output voltage FA i , branch output voltage average FB, branch output current FC i , branch output current average FD and photovoltaic module rated power FE.

[0113] It should be noted that the DC cabinet branch output voltage FA i is the DC voltage value measured from the output end of each branch of the DC cabinet, with the unit of volt. These voltage values reflect the potential difference of the DC electric energy output by the photovoltaic modules or photovoltaic arrays in each branch, which is one of the important parameters for evaluating the photovoltaic system power generation performance and electric energy transmission state. It is measured and obtained using a DC voltmeter. The DC cabinet is a device used for collecting and distributing DC electric energy in the photovoltaic power generation system. The branch output voltage average FB is the arithmetic average of the output voltages of all branches of the DC cabinet, with the unit of volt. It can reflect the average level of the overall output voltage of the DC cabinet and is used for macroscopic evaluation of the DC cabinet output voltage state. The method for obtaining it is as follows: use a DC voltmeter to obtain the output voltage values of each branch of the DC cabinet at the same time, add these voltage values and divide by the number of branches to obtain the branch output voltage average FB. The branch output current FC iThe direct current refers to the actual direct current flowing in each branch of the direct current cabinet, and the unit is ampere. It reflects the ability of photovoltaic modules or photovoltaic arrays in each branch to output power to the direct current cabinet. The direct current is measured and obtained by using a direct current ammeter. The branch output current average FD is the arithmetic average of the output currents of all branches of the direct current cabinet, and the unit is ampere. The method for obtaining is as follows: the output current values of each branch of the direct current cabinet at the same time are obtained by using a direct current ammeter, and the current values are added and divided by the number of branches to obtain the branch output current average FD. The rated power FE of the photovoltaic module refers to the maximum power that the photovoltaic module can output under standard test conditions, and the unit is watt. It is used to represent the power generation capacity of the module. It is obtained by checking the module nameplate or technical specification. The standard test conditions are usually as follows: the light intensity is 1000 W / m 2 , the module temperature is 25℃, and the atmospheric mass is AM1.5.

[0114] The photovoltaic power generation system index WD is calculated according to the branch output voltage FA i , the branch output voltage average FB, the branch output current FC i , the branch output current average FD, the photovoltaic module output power AA a and the rated power FE of the photovoltaic module. The formula is as follows:

[0115]

[0116] Wherein, FA i is the output voltage of the i-th branch in the direct current cabinet, i is the serial number corresponding to different branches, and the value is [1, m]; m is the total number of branches in the direct current cabinet, and the value is a positive integer; FC i is the output current of the i-th branch in the direct current cabinet.

[0117] It should be noted that the operation principle of the formula is as follows: is the average value of the absolute value sum of the difference between the output power of each photovoltaic module and the rated power. It reflects the deviation degree of the actual output power of the photovoltaic module and the rated power. If the deviation degree is small, it means that the module runs in a relatively ideal state and can approach its designed power generation capacity. It has a positive contribution to the system performance, and the photovoltaic power generation system index WD will be higher, is the proportion of the absolute value sum of the difference between the branch output voltage and the branch output voltage average and the product of the branch number and the branch output voltage average. It is used to measure the size of the dispersion degree of the branch output voltage of the direct current cabinet relative to the branch output voltage average, is the ratio of the sum of the absolute values of the differences between the branch output currents and the average value of the branch output currents and the product of the number of branches and the average value of the branch output currents, which reflects the size of the dispersion degree of the output currents of each branch of the DC cabinet relative to the average value of the branch output currents. The smaller the dispersion degree of the output voltage and current of each branch of the DC cabinet, the more uniform the power transmission and distribution of each branch, the higher the stability and reliability of the system, and the higher the photovoltaic power generation system index WD. Conversely, if the dispersion degree is large, there may be branch faults, line impedance imbalance and other problems, which will affect the overall performance of the system, and the photovoltaic power generation system index WD will be lower. The formula uses the negative exponential form of the exponential function to comprehensively evaluate the state of the photovoltaic power generation system from three aspects: the deviation degree of the output power of the photovoltaic module from the rated power, the dispersion degree of the output voltage of each branch of the DC cabinet, and the dispersion degree of the output current of each branch of the DC cabinet, to obtain the photovoltaic power generation system index WD. Wherein, e is the base of the natural logarithm in the exponential function.

[0118] Step 206: The method for calculating the energy storage system state index WE is:

[0119] The energy storage system data further includes an initial state of charge GA, a battery pack rated capacity GB, a battery pack charge and discharge current GC(t), a battery pack initial internal resistance GD, and a battery pack current internal resistance GE.

[0120] It should be noted that the initial state of charge GA refers to the ratio of the amount of charge stored by the energy storage battery to the rated capacity of the battery pack, usually expressed in percentage, which reflects the amount of electricity when the battery is not operated or just started to be used, and is one of the important parameters for the operation management and control of the energy storage system, which is obtained by checking the initial setting of the battery management system or the state of charge recorded at the last shutdown. The rated capacity GB of the battery pack refers to the amount of electricity that the battery pack can discharge under specified discharge conditions, usually in ampere-hours, which is an important performance indicator of the battery pack and represents the ability of the battery pack to store electrical energy. It is obtained by checking the product specification or nameplate of the battery pack. The battery pack charging and discharging current GC(t) refers to the size of the current flowing through the battery pack during charging and discharging, which is a quantity that changes with time, and the unit is ampere. When GC(t) is positive, it means that the battery pack is charging, and the current flows into the battery pack. When GC(t) is negative, it means that the battery pack is discharging, and the current flows out of the battery pack. It is obtained by real-time measurement using current sensors such as Hall current sensors and shunts. The initial internal resistance GD of the battery pack refers to the internal resistance of the battery pack when it is not operated or just started to be charged and discharged, and the unit is ohm. It is measured using professional internal resistance testers such as UT677A+ battery internal resistance tester and RTBT-9000 intelligent storage battery internal resistance tester when the battery pack is not operated. The current internal resistance GE of the battery pack refers to the actual internal resistance of the battery pack at the current time, and the unit is ohm, which reflects the change of the internal resistance of the battery under the current working condition. It is measured using professional internal resistance testers such as UT677A+ battery internal resistance tester and RTBT-9000 intelligent storage battery internal resistance tester.

[0121] The energy storage system state index WE is calculated according to the initial state of charge GA, the rated capacity GB of the battery pack, the battery pack charging and discharging current GC(t), the initial internal resistance GD of the battery pack and the current internal resistance GE of the battery pack. The formula is:

[0122]

[0123] Wherein, GC(t) is the battery pack charging and discharging current at time point t, t is the serial number corresponding to different time points, and t1 is the length of the detection period.

[0124] It should be noted that the running principle of the formula is: is to convert the integral of current with respect to time into a dimension comparable to the initial state of charge, is the amount of charge charged or discharged by the battery pack from the initial time to the current time, is used to measure the degree of change of the initial state caused by the charging and discharging amount of the battery in this period, The lower the value, the higher the aging degree, and the worse the energy storage effect. The formula obtains the state index WE of the energy storage system by squaring and opening the root of the two indicators, comprehensively considering the influence of the above two aspects.

[0125] Step 207: The method for calculating the power equipment operation state index X is:

[0126] The power equipment operation state index X is calculated according to the photovoltaic power generation-energy storage system coordination efficiency index WA, the power transmission line stability index WB, the photovoltaic power generation-inverter coordination index WC, the photovoltaic power generation system index WD and the energy storage system state index WE, and the formula is:

[0127]

[0128] It should be noted that the formula is based on the concept of geometric mean, and comprehensively considers the influence of the photovoltaic power generation-energy storage system coordination efficiency index WA, the power transmission line stability index WB, the photovoltaic power generation-inverter coordination index WC, the photovoltaic power generation system index WD and the energy storage system state index WE, emphasizes the balance and coordination relationship between each index, and finally obtains the power equipment operation state index X.

[0129] Combining the contents of steps 201 to 207:

[0130] The photovoltaic power generation-energy storage system coordination efficiency index WA is calculated based on photovoltaic power generation system data, energy storage system data and overall data, which can accurately measure the coordination of the photovoltaic power generation system and the energy storage system in actual operation, and help to determine the optimal configuration ratio of the photovoltaic power generation system and the energy storage system. The power transmission line stability index WB is calculated based on inverter and grid-connected system data and power transmission line data, which not only reflects the condition of the power transmission line itself, but also reflects the influence of the inverter and grid-connected system on the stability of power transmission, comprehensively grasps various factors in the power transmission process, and helps to find potential weak links in the system. The photovoltaic power generation-inverter coordination index WC is calculated based on photovoltaic power generation system data and inverter and grid-connected system data, which comprehensively considers the data of the two key links of photovoltaic power generation and inverter grid connection, can comprehensively evaluate the efficiency of the entire power generation and grid connection process, and intuitively show whether the two can work efficiently under different working conditions, providing a key reference for evaluating the overall performance of the system. The photovoltaic power generation system index WD is calculated based on photovoltaic power generation system data, which can reflect the running state of the photovoltaic power generation system in real time, understand the power generation level of the system under different light conditions, and evaluate whether it meets the design requirements and expected goals. The energy storage system state index WE is calculated based on energy storage system data, which can understand the energy storage level of the energy storage system and the loss in the energy conversion process, and provide a reference for optimizing system operation. The power equipment running state index X is calculated based on the photovoltaic power generation-energy storage system coordination efficiency index WA, the power transmission line stability index WB, the photovoltaic power generation-inverter coordination index WC, the photovoltaic power generation system index WD and the energy storage system state index WE, which is conducive to the comprehensive analysis of the overall running state of the equipment, avoids misjudgment or omission caused by single index judgment, and solves the problem that the traditional monitoring system often only pays attention to the running state of a single device, ignores the cooperative working relationship between different devices and systems, and cannot comprehensively evaluate the running state of the entire photovoltaic storage project, and cannot find potential problems in the system in time.

[0131] Step 3: preset a set of running state thresholds; determine the running state of the power equipment according to the power equipment running state index X and the set of running state thresholds, and select a warning method according to the running state of the power equipment.

[0132] Step 3 includes the following steps:

[0133] Step 301: the method for determining the running state of the power equipment is:

[0134] The set of running state thresholds includes a normal running state threshold YC, a medium risk threshold YZ and a high risk threshold YG.

[0135] It should be noted that the determination method of the normal operation state threshold YC, the medium risk threshold YZ and the high risk threshold YG is: collecting data of the light storage project in different periods under the normal operation state, calculating the power equipment operation state index data in different periods according to the above method, further calculating the average value and the standard deviation of the power equipment operation state index data, calculating the value of the average value minus one times the standard deviation as the reference value of the normal operation state threshold YC, calculating the value of the average value plus one times the standard deviation as the reference value of the medium risk threshold YZ, and calculating the value of the average value plus two times the standard deviation as the reference value of the high risk threshold YG.

[0136] According to the power equipment operation state index X and the operation state threshold set, the power equipment operation state is judged, and the standard is:

[0137]

[0138] When it is the normal operation state, the early warning mode one is selected, specifically: in the control center or the equipment panel of the light storage project, different color indicator lights are set to represent the system state, when the system normally operates, the indicator light is green, at the same time, the sensors and the intelligent monitoring system continuously collect various operation parameters of the power equipment, and regularly send emails to the operation and maintenance personnel and the relevant person in charge to report the operation state of the system, when the system appears some conditions that need to be concerned although they do not affect the normal operation, such as the increase of the loss rate of a certain equipment, the operation and maintenance personnel and the relevant person in charge are immediately notified by sending emails.

[0139] When it is the low risk operation state, the early warning mode two is selected, specifically: when it is the low risk operation state, the indicator light is yellow, at the same time, the monitoring system automatically sends a short message to the mobile phone of the operation and maintenance personnel, informing that the system is in the low risk operation state and the related parameters and specific problems leading to the risk.

[0140] When it is the medium risk operation state, the early warning mode three is selected, specifically: when it is the medium risk operation state, the indicator light is red, the key parameters of the equipment or system appearing the medium risk are real-time concerned, at the same time, a short message and an email are sent to the operation and maintenance personnel and the relevant person in charge, informing the detailed information of the medium risk, in addition to the risk description and parameter data, the email and the short message should also be attached with the processing experience and the reference scheme of the historical similar cases, providing decision support for the operation and maintenance personnel.

[0141] When the running state is high risk, the fourth early warning mode is selected, specifically: once the monitoring system detects that the running state is high risk, the sound alarm is triggered immediately, the indicator light turns orange, and the emergency notification is sent to the relevant person in charge through various communication channels such as SMS, telephone, email or special application, and at the same time the monitoring frequency of the key indicators is increased to ensure that the development trend of abnormal conditions can be captured more frequently, and the running is stopped when the abnormal conditions continue to develop.

[0142] In combination with the content of step 301:

[0143] According to the power equipment running state index X and the running state threshold set, the running state of the power equipment is judged, which can reflect the equipment condition in real time and provide accurate equipment running information for the operation and maintenance personnel, and according to the power equipment running state, the early warning method is selected, which is beneficial to find the potential problems and fault hidden dangers of the equipment in advance, avoid the occurrence of equipment failure, and ensure the stable operation of the equipment.

[0144] On the other hand, the application also discloses a high-altitude power equipment condition monitoring system for realizing the high-altitude power equipment condition monitoring method, comprising:

[0145] The data acquisition module is used for acquiring photovoltaic power generation system data, energy storage system data, overall data, inverter and grid connection system data and power transmission line data of the photovoltaic storage project.

[0146] The index calculation module can calculate the photovoltaic power generation-energy storage system cooperation efficiency index WA based on the photovoltaic power generation system data, the energy storage system data and the overall data, calculate the power transmission line stability index WB based on the inverter and grid connection system data and the power transmission line data, calculate the power transmission consistency index QA based on the inverter and grid connection system data, calculate the photovoltaic power generation-inverter cooperation index WC according to the power transmission consistency index QA, the photovoltaic power generation system data and the inverter and grid connection system data, calculate the photovoltaic power generation system index WD based on the photovoltaic power generation system data, calculate the energy storage system state index WE based on the energy storage system data, and calculate the power equipment running state index X according to the photovoltaic power generation-energy storage system cooperation efficiency index WA, the power transmission line stability index WB, the photovoltaic power generation-inverter cooperation index WC, the photovoltaic power generation system index WD and the energy storage system state index WE.

[0147] The judgment module can preset a running state threshold set, judge the running state of the power equipment according to the power equipment running state index X and the running state threshold set, and select the early warning method according to the power equipment running state.

[0148] The above-described embodiments can be implemented in whole or in part by software, hardware, firmware, or any combination thereof. When implemented by software, the above-described embodiments can be implemented in whole or in part in the form of a computer program product. A person of ordinary skill in the art can be aware that units and algorithm steps of the examples described in connection with the embodiments disclosed herein can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on the specific application and design constraints of the technical solutions.

[0149] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, i.e., can be located in one place or can be distributed on multiple network units. Part or all of the units can be selected to achieve the purpose of the embodiments according to actual needs.

[0150] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for monitoring the condition of high-altitude power equipment, characterized in that: Includes the following steps: Collect data on photovoltaic power generation systems, energy storage systems, overall data, inverter and grid-connected systems, and transmission lines for photovoltaic-storage projects; The photovoltaic (PV) power generation and energy storage system synergy efficiency index WA is calculated based on PV power generation system data, energy storage system data, and overall data. The transmission line stability index WB is calculated based on inverter and grid-connected system data and transmission line data. The power transmission consistency index QA is calculated based on inverter and grid-connected system data. The PV power generation and inverter synergy index WC is calculated based on the power transmission consistency index QA, PV power generation system data, and inverter and grid-connected system data. The PV power generation system index WD is calculated based on PV power generation system data. The energy storage system status index WE is calculated based on energy storage system data. The power equipment operating status index X is calculated based on the PV power generation and energy storage system synergy efficiency index WA, transmission line stability index WB, PV power generation and inverter synergy index WC, PV power generation system index WD, and energy storage system status index WE. Preset a set of operating status thresholds; determine the operating status of power equipment based on the power equipment operating status index X and the set of operating status thresholds, and select an early warning method based on the operating status of power equipment; The starting time for the change in photovoltaic module power is AE; The energy storage system begins its response at AF. ； Among them, AA a Let AB represent the output power of the photovoltaic module at the a-th sampling time point, where a is the sequence number corresponding to different sampling time points, taking the value [1, b]; b is the total number of sampling time points, taking the value as a positive integer; a The charging or discharging power of the energy storage system at the a-th sampling time point; AC a The useful power that meets the load demand at the a-th sampling time point; The fundamental current RMS value is BB, and the rated output current RMS value is BD; The resistance of the transmission line is CA, and the reactance of the transmission line is CB; ； Among them, BA d Let f be the effective value of the harmonic current of the d-th harmonic, where d is the index of the different harmonics and takes the value [1, f]; f is the total number of harmonics and takes the value of a positive integer. ； Among them, DA a Let DB be the input power of the inverter at the a-th sampling time point; a Let the output power of the inverter be the output power at the a-th sampling time point; The output voltage frequency is EA; The grid frequency is EB, the grid rated frequency is EC, the inverter conversion efficiency is ED, and the average inverter conversion efficiency is EE. ； Where α1 is the weighting coefficient of the power transmission consistency index (QA), with a value ranging from 0.3 to 0.5; α2 is... The weighting coefficients range from 0.2 to 0.5; α3 is... The weighting coefficients are 0.2 to 0.5; and α1 + α2 + α3 = 1. The average branch output voltage is FB, the average branch output current is FD, and the rated power of the photovoltaic module is FE; ； Among them, FA i FC represents the output voltage of the i-th branch in the DC cabinet, where i is the index of the different branches, taking the value [1, m]; m is the total number of branches in the DC cabinet, taking the value as a positive integer; i Let be the output current of the i-th branch in the DC cabinet; The initial state of charge is GA, the rated capacity of the battery pack is GB, the initial internal resistance of the battery pack is GD, and the current internal resistance of the battery pack is GE. ； Where GC(t) is the battery pack charging and discharging current at time point t, t is the sequence number corresponding to different time points, and t1 is the duration of the detection cycle.

2. The method for monitoring the condition of high-altitude power equipment according to claim 1, characterized in that: The method for calculating the operating status index X of power equipment is as follows: The operating status index X of power equipment is calculated based on the synergistic efficiency index WA of photovoltaic power generation-energy storage system, the stability index WB of transmission line, the synergistic index WC of photovoltaic power generation-inverter, the photovoltaic power generation system index WD, and the state index WE of energy storage system. The formula used is as follows: 。 3. The method for monitoring the condition of high-altitude power equipment according to claim 2, characterized in that: The method for determining the operating status of power equipment is as follows: The set of operating status thresholds includes the normal operating status threshold YC, the medium risk threshold YZ, and the high risk threshold YG; The operating status of power equipment is determined based on the operating status index X and the set of operating status thresholds. The standard used is as follows: ； When the system is in normal operating condition, select warning mode one; When the operation is in a low-risk state, select early warning method two; When the operation is in a medium-risk state, select early warning mode three; When the system is in a high-risk operating state, select warning method four.

4. A system for monitoring the condition of high-altitude power equipment according to claim 1, characterized in that: The system includes: The data acquisition module is used to collect data from the photovoltaic power generation system, energy storage system, overall data, inverter and grid connection system, and transmission line data of the photovoltaic-storage project. The index calculation module can calculate the photovoltaic-energy storage system synergy efficiency index WA based on photovoltaic power generation system data, energy storage system data, and overall data; calculate the transmission line stability index WB based on inverter and grid-connected system data and transmission line data; calculate the power transmission consistency index QA based on inverter and grid-connected system data; calculate the photovoltaic-inverter synergy index WC based on the power transmission consistency index QA, photovoltaic power generation system data, and inverter and grid-connected system data; calculate the photovoltaic power generation system index WD based on photovoltaic power generation system data; calculate the energy storage system status index WE based on energy storage system data; and calculate the power equipment operating status index X based on the photovoltaic-energy storage system synergy efficiency index WA, transmission line stability index WB, photovoltaic-inverter synergy index WC, photovoltaic power generation system index WD, and energy storage system status index WE. The judgment module can preset a set of operating status thresholds; judge the operating status of the power equipment based on the power equipment operating status index X and the set of operating status thresholds; and select an early warning method based on the operating status of the power equipment.

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