Alternating-current micro-grid system based on multi-port alternating-current transformer substation

Abstract

The invention relates to the technical field of power management, in particular to an alternating-current micro-grid system based on a multi-port alternating-current transformer substation, which comprises a port current fluctuation detection module, a dynamic partition module, a load adjustment module, a harmonic characteristic detection module and a phase synchronization module. According to the invention, the amplitude, the phase and the frequency of the current are monitored in real time, the current abnormity is found in time, the real-time performance can quickly respond to the system change, reduce the potential power loss and fault diffusion, intelligently screen the abnormal current and quickly isolate the fault port, and the fault influence range can be effectively reduced. By optimizing power compensation distribution, it is ensured that the system can still maintain enough operation load and increase the elasticity of a power grid even under the condition that part of ports are isolated, and by means of accurate analysis and matching of harmonic data and optimization of selection of reconnection ports, the overall operation efficiency of the power system is improved. And the power grid is more economical and efficient.

Description

Technical Field

[0001] The present invention relates to the technical field of power management, and in particular to an AC microgrid system based on a multi-port AC substation. Background Art

[0002] The field of power management technology includes methods and technologies for optimizing the control of generation, transmission, distribution and consumption in power systems. The core content is to improve the efficiency and reliability of power systems while ensuring the stability and economy of energy supply. Power management involves demand response, load management, fault detection and response, and real-time monitoring of the power grid to ensure that the power grid can maintain balance and efficient operation under various operating conditions, including automatic adjustment of power distribution during high demand periods and storage of excess energy when there is oversupply.

[0003] Among them, the AC microgrid system of the multi-port AC substation is used to integrate multiple power sources and loads into a unified power management system. The technical matters targeted by the patent subject cover connecting and managing various power sources, including renewable energy and traditional energy, and different power loads through multi-port substations. Specific methods include making the parallel connection and configuration of each power source more flexible through multi-port configuration, optimizing the distribution and use of electricity through an intelligent management system, and ensuring the continuity of power supply and the stability of the system.

[0004] While existing technologies have improved the efficiency and reliability of power systems, they still have some operational deficiencies. For example, in power systems, existing power management technologies are not flexible enough in responding to current anomalies, resulting in a slow response when detecting and isolating fault points, which will cause the impact of the fault to expand and increase the instability and safety risks of the system. Deficiencies in load management result in the inability to make effective power adjustments in a timely manner when a fault occurs, affecting the continuous power supply capacity of the power grid. Traditional technologies are also relatively limited in their capabilities in harmonic processing and phase synchronization, which will affect the overall energy efficiency and power supply quality of the power grid, especially in large-scale or complex power grids, which are not sufficient to handle the dynamic changes of multiple sources and multiple loads. In actual operations, the deficiencies lead to unstable power supply and increased operating costs, and are particularly evident during high-demand periods or under extreme conditions, affecting users' power experience and the economy of the system. Summary of the invention

[0005] In order to solve the problems that the existing technology is not flexible enough in responding to current anomalies, the response speed is slow when detecting and isolating the fault point, which will cause the impact of the fault to expand and increase the instability and safety risks of the system. Deficiencies in load management result in the inability to make effective power adjustments in time when a fault occurs, affecting the continuous power supply capacity of the power grid. The capabilities of traditional technologies in harmonic processing and phase synchronization are also relatively limited, which will affect the overall energy efficiency and power supply quality of the power grid, especially in large-scale or complex power grids, which are not enough to handle the dynamic changes of multiple sources and multiple loads. The shortcomings lead to unstable power supply and increased operating costs in actual operations, and are particularly evident in high-demand periods or extreme conditions, affecting the user's power experience and the economy of the system. The technical problem, an embodiment of the present invention provides an AC microgrid system based on a multi-port AC substation. The technical solution is as follows:

[0006] On the one hand, an AC microgrid system based on a multi-port AC substation is provided, the system comprising:

[0007] The port current fluctuation detection module collects the amplitude, phase and frequency data of the port current signal, determines whether the current is abnormal, analyzes the current amplitude, phase and frequency fluctuations by setting thresholds, screens abnormal ports, and obtains abnormal port identification data;

[0008] The dynamic partitioning module screens the current data of adjacent ports based on the abnormal port identification data, identifies the load capacity of multiple ports, evaluates the impact range of the fault point according to the power flow distribution, performs partition isolation, selects the load port as the isolation boundary, and generates the optimal partition isolation boundary;

[0009] The load adjustment module records the power loss of the isolated port of the AC microgrid through the optimal partition isolation boundary, calculates the power margin of the port that is still in operation, determines whether the power margin is sufficient to compensate for the load loss of the isolated port, selects the port whose load is close to the fault point for power compensation, and obtains the power compensation allocation result;

[0010] The harmonic feature detection module uses the power compensation allocation result to identify the amplitude and phase distribution of the harmonics, evaluate the harmonic matching degree between the reconnection port and the breakpoint, select the ports close to the breakpoint harmonics for reconnection, and generate the harmonic matching reconnection port.

[0011] As a further solution of the present invention, the abnormal port identification data includes abnormal current amplitude identification information, abnormal phase deviation record, and frequency mutation data; the optimal partition isolation boundary includes load capacity assessment data, fault point impact range assessment results, and partition isolation information; the power compensation allocation result includes power loss data, power margin, and power compensation allocation record; the harmonic matching reconnection port includes the identified harmonic amplitude, phase distribution data, reconnection port harmonic matching assessment results, and the selected harmonic matching reconnection port identification.

[0012] As a further solution of the present invention, the port current fluctuation detection module includes:

[0013] The current signal acquisition submodule collects the amplitude, phase and frequency data of the port current signal, calculates the current amplitude change, phase change and frequency change during continuous time, arranges them in time series, and obtains current change sequence data;

[0014] The amplitude-phase analysis submodule calculates the amplitude change rate, phase offset and frequency fluctuation rate through the current change sequence data, compares the amplitude change rate with the amplitude threshold, the phase offset with the phase threshold, filters out the signals exceeding the threshold, identifies the fluctuation degree in combination with the frequency fluctuation rate, and obtains the current fluctuation characteristic parameters;

[0015] The abnormal port screening submodule uses the current fluctuation characteristic parameters and refers to the port fluctuation degree to compare the normal port with the abnormal port, identifies the deviation degree, records the abnormal port number, and obtains abnormal port identification data.

[0016] As a further solution of the present invention, the dynamic partitioning module includes:

[0017] The adjacent port screening submodule uses the abnormal port identification data to screen the port current data adjacent to the abnormal port, calculates the current difference between the adjacent ports, records the adjacent port numbers, and obtains the adjacent port current data;

[0018] The load capacity identification submodule calculates the load capacity values ​​of multiple ports based on the adjacent port current data, analyzes the ratio of the port current carrying capacity to the port rated load value, analyzes the influence of the abnormal port on the adjacent port according to the power flow distribution, and obtains the fault impact range identification result;

[0019] The partition isolation submodule uses the fault impact range identification result to calculate the load capacity value of the port, and prioritizes it, uses the prioritized port as the isolation boundary, isolates the power supply channel of the fault point, determines the optimal partition position, and obtains the optimal partition isolation boundary.

[0020] As a further solution of the present invention, the formula for calculating the load capacity value of the port is:

[0021]

[0022] Among them, P b Represents the load capacity value, L i Represents the power demand of the i-th load device, W i Represents the load weight of the i-th load device, I j Represents the real-time current of the jth power supply channel, I avg Represents the average current of the power supply channel, V k represents the voltage at the kth isolation boundary, V ref represents the reference voltage, n represents the total number of load devices, m represents the total number of power supply channels, and p represents the total number of isolation boundary locations.

[0023] As a further solution of the present invention, the load adjustment module includes:

[0024] The power loss calculation submodule adopts the optimal partition isolation boundary, records the power loss information of the isolated port, analyzes the power gap of the isolated port, and obtains the power loss record of the isolated port;

[0025] The power margin judgment submodule calculates the power margin value of the port that is still in operation based on the power loss record of the isolated port, compares the power margin value with the power loss value, determines whether the power margin meets the compensation requirement, screens the ports whose power margin exceeds the compensation requirement, and obtains the compensation power port set;

[0026] The allocation ratio adjustment submodule uses the compensation power port set to screen ports whose loads are close to the fault point, calculate the compensation power, adjust the compensation allocation ratio, and obtain the power compensation allocation result.

[0027] As a further solution of the present invention, the formula for calculating the compensation power is:

[0028]

[0029] Among them, Z c,o represents the compensation power at port o, Z d,a Represents the required power of load port a, Z f,a Represents the mismatch power of port a at the fault point, W a,o represents the weight coefficient between port a and port o, and N represents the total number of load ports.

[0030] As a further solution of the present invention, the harmonic feature detection module includes:

[0031] The harmonic amplitude and phase extraction submodule uses the power compensation allocation result to extract the harmonic current signals of multiple ports in the AC microgrid, extracts the amplitude information from the harmonic current signals, records the amplitude and phase distribution corresponding to the multiple ports, and obtains the port harmonic amplitude and phase data;

[0032] The harmonic matching comparison submodule identifies the harmonic amplitude and phase of the breakpoint port based on the port harmonic amplitude and phase data, compares the harmonic amplitude and phase data of the port with the harmonic amplitude and phase data of the breakpoint port, selects ports with similar amplitudes, and obtains the port harmonic matching result;

[0033] The priority screening submodule screens the ports with priority matching through the port harmonic matching results, combines the harmonic data of the matching ports with the breakpoint port data, performs iterative verification, selects the ports with priority matching as the reconnection ports, and obtains the harmonic matching reconnection ports.

[0034] As a further solution of the present invention, the system further includes a phase synchronization module:

[0035] The phase synchronization module reconnects the port based on the harmonic matching, records the voltage of the target port, adjusts the voltage amplitude, matches it with the fault point, determines the consistency of the phase of the newly connected port with the phase of the fault point, and generates the AC microgrid phase control result by adjusting the phase of the new port to synchronize with the fault point;

[0036] The AC microgrid phase control result includes adjusted voltage amplitude data, a phase matching evaluation result between a new access port and a fault point, and phase control information.

[0037] As a further solution of the present invention, the phase synchronization module includes:

[0038] The target port voltage adjustment submodule records the voltage and voltage amplitude of the target port based on the harmonic matching reconnection port, adjusts the voltage amplitude of the target port to a set range, and matches it with the voltage amplitude of the fault point to obtain a target port voltage matching record;

[0039] The phase consistency judgment submodule uses the target port voltage matching record to extract the phase information of the target port, compares the phase information of the target port with the phase data of the fault point, identifies the range of the phase deviation, and obtains the target port phase deviation identification result;

[0040] The phase synchronization control submodule uses the target port phase deviation identification result to adjust the phase of the target port, evaluate the consistency with the fault point phase, record the phase adjusted state of the AC microgrid target port, and obtain the AC microgrid phase control result.

[0041] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0042] By real-time monitoring of the current amplitude, phase and frequency, current anomalies can be detected in time. This real-time performance can quickly respond to system changes and reduce potential power losses and fault propagation. Intelligent screening of abnormal currents and rapid isolation of faulty ports can effectively reduce the scope of fault impact and enhance the safety and stability of the system. Load adjustment measures optimize power compensation distribution to ensure that the system can maintain sufficient operating load even when some ports are isolated, thereby increasing the resilience of the power grid. Through precise analysis and matching of harmonic data, the system can optimize the selection of reconnection ports while ensuring the quality of the power grid. This not only improves the overall operating efficiency of the power system, but also optimizes the use of energy, making the power grid more economical and efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 is a schematic diagram of an AC microgrid system based on a multi-port AC substation provided by an embodiment of the present invention;

[0045] Figure 2 It is a schematic diagram of the system framework of the present invention;

[0046] Figure 3 This is a flow chart of the port current fluctuation detection module of the present invention;

[0047] Figure 4 This is a flow chart of the dynamic partitioning module of the present invention;

[0048] Figure 5 This is a flow chart of the load adjustment module of the present invention;

[0049] Figure 6 This is a flow chart of the harmonic feature detection module of the present invention;

[0050] Figure 7 This is a flow chart of the phase synchronization module of the present invention. DETAILED DESCRIPTION

[0051] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0052] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0053] In the embodiments of the present invention, "image" and "picture" can sometimes be used interchangeably. It should be noted that when the difference between them is not emphasized, the meanings they intend to express are the same. "of", "corresponding, relevant" and "corresponding" can sometimes be used interchangeably. It should be noted that when the difference between them is not emphasized, the meanings they intend to express are the same.

[0054] In the embodiments of the present invention, sometimes the subscripts such as W 1 It may be written in non-subscript form such as W1. When the difference is not emphasized, the meaning is the same.

[0055] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0056] The embodiment of the present invention provides an AC microgrid system based on a multi-port AC substation, such as Figure 1-2 The schematic diagram of an AC microgrid system based on a multi-port AC substation is shown, and the system includes:

[0057] The port current fluctuation detection module collects the amplitude, phase and frequency data of the port current signal, determines whether the current is abnormal, analyzes the current amplitude, phase and frequency fluctuations by setting thresholds, detects amplitude changes, phase deviations and frequency mutations, screens abnormal signal fluctuation characteristics, screens abnormal ports, and obtains abnormal port identification data;

[0058] The dynamic partitioning module screens the current data of adjacent ports based on abnormal port identification data, identifies the load capacity of multiple ports, evaluates the impact range of the fault point according to the power flow distribution, performs partition isolation, selects the load port as the isolation boundary, isolates the power supply channel of the fault point, and generates the optimal partition isolation boundary;

[0059] The load adjustment module records the power loss of the isolated port of the AC microgrid through the optimal partition isolation boundary, calculates the power margin of the port that is still in operation, determines whether the power margin is sufficient to compensate for the load loss of the isolated port, selects the port whose load is close to the fault point for power compensation, and obtains the power compensation allocation result;

[0060] The harmonic feature detection module uses the power compensation allocation results to identify the amplitude and phase distribution of harmonics, extract the harmonic data of the reconnection port in the AC microgrid, evaluate the harmonic matching degree between the reconnection port and the breakpoint, select the ports close to the breakpoint harmonics for reconnection, and generate harmonically matched reconnection ports;

[0061] The phase synchronization module reconnects the port based on harmonic matching, records the voltage of the target port, adjusts the voltage amplitude, and matches it with the fault point, determines the consistency of the phase of the newly connected port with the phase of the fault point, and generates the AC microgrid phase control result by adjusting the phase of the new port to synchronize with the fault point;

[0062] The abnormal port identification data includes abnormal current amplitude identification information, abnormal phase deviation records, and frequency mutation data. The optimal partition isolation boundary includes load capacity assessment data, fault point impact range assessment results, and partition isolation information. The power compensation allocation results include power loss data, power margin, and power compensation allocation records. The harmonic matching reconnection port includes the identified harmonic amplitude, phase distribution data, reconnection port harmonic matching assessment results, and selected harmonic matching reconnection port identification. The AC microgrid phase control results include adjusted voltage amplitude data, phase matching assessment results between the new access port and the fault point, and phase control information.

[0063] Specifically, if Figure 2 , 3 As shown, the port current fluctuation detection module includes:

[0064] The current signal acquisition submodule collects the amplitude, phase and frequency data of the port current signal, calculates the current amplitude change, phase change and frequency change during continuous time, arranges them in time series, and obtains current change sequence data;

[0065] Real-time data of the port current signal is obtained through a high-precision sensor, including amplitude, current phase and frequency information. During the sampling process, a high-speed analog-to-digital converter (ADC) is used to digitize the analog signal to ensure the accuracy of data acquisition. The data is stored in the buffer area and sorted by timestamp to ensure data continuity. By comparing the current amplitude, phase and frequency values ​​of adjacent sampling points, the corresponding changes are calculated, namely the amplitude change ΔA, phase change Δφ and frequency change Δf. The calculation formula is as follows:

[0066] ΔA=A n -A n-1 ;

[0067] Δφ=φ n -φ n-1 ;

[0068] Δf=f n -fn-1 ;

[0069] Among them, A n ,φ n and f n Respectively represent the current amplitude, phase and frequency at the nth time point;

[0070] All the change data are arranged in chronological order to form the current change sequence data. At a certain port, if the current amplitudes at the previous and next moments are 10A and 10.5A respectively, the amplitude change is:

[0071] ΔA = 10.5-10 = 0.5;

[0072] If the phase angle changes from 45° to 50°, then:

[0073] Δφ=50-45=5°;

[0074] If the frequency changes from 50Hz to 49.8Hz, then:

[0075] Δf = 49.8-50 = -0.2 Hz;

[0076] All changes are stored and arranged according to timestamps to form current change sequence data.

[0077] The amplitude-phase analysis submodule calculates the amplitude change rate, phase offset and frequency fluctuation rate through the current change sequence data, compares the amplitude change rate with the amplitude threshold, and the phase offset with the phase threshold, filters out the signals exceeding the threshold, identifies the fluctuation degree in combination with the frequency fluctuation rate, and obtains the current fluctuation characteristic parameters;

[0078] Process the current change sequence data and calculate the amplitude change rate R A , phase shift Δφ and frequency fluctuation rate R f , the calculation formula is as follows:

[0079]

[0080] Amplitude change rate R A Represents the relative size of the current amplitude change. If the amplitude change of a port at adjacent moments is 0.5A, and the current amplitude at the previous moment is 10A, then the amplitude change rate is:

[0081]

[0082] The phase offset is directly calculated using Δφ. If the phase angle changes from 45° to 50° at a certain moment, then Δφ = 5°;

[0083] Frequency volatility R fTo measure the degree of frequency change, if the frequency change at a certain moment is -0.2Hz, and the frequency at the previous moment is 50Hz, then the frequency fluctuation rate is:

[0084]

[0085] Amplitude change rate and set threshold T A For comparison, if R A >T A The change data is filtered out, and the phase offset and phase threshold T φ For comparison, if Δφ>T φ Then filter out the signal and set the amplitude change threshold to 4%. If the amplitude change rate R is calculated A =5%, then filter out the data, and set the phase threshold to 4°. If Δφ=5°, filter out the data in the same way. The filtered data is combined with the frequency fluctuation rate R f Evaluate the degree of fluctuation and extract characteristic parameters of current fluctuation.

[0086] The abnormal port screening submodule uses the current fluctuation characteristic parameters and refers to the port fluctuation degree to compare the normal port with the abnormal port, identify the deviation degree, record the abnormal port number, and obtain the abnormal port identification data;

[0087] Calculate the fluctuation degree of each port and analyze it with reference to the overall port data to determine the benchmark fluctuation value B and calculate the average fluctuation rate of the port. The formula is as follows:

[0088]

[0089] Where N is the total number of ports, represents the amplitude change rate of the i-th port;

[0090] If the system has 5 ports, and their amplitude change rates are 2%, 3%, 5%, 8%, and 10% respectively, then:

[0091]

[0092] Calculate the deviation degree D of a single port i , the formula is as follows:

[0093]

[0094] If the amplitude change rate of port 3 The degree of deviation D 3 =8-5.6=2.4%, set the abnormal threshold T D , if D i >T D or D i <-T D, then the port is marked as an abnormal port. If the abnormal threshold T is set D =2%, then port 3 exceeds 2% and is marked as abnormal, and abnormal port identification data is obtained.

[0095] Specifically, if Figure 2 , 4 As shown, the dynamic partitioning module includes:

[0096] The adjacent port screening submodule uses abnormal port identification data to screen the port current data adjacent to the abnormal port, calculates the current difference between adjacent ports, records the adjacent port numbers, and obtains the adjacent port current data;

[0097] Determine the adjacent ports of the abnormal port and obtain the current data of the adjacent ports. Through the port topology relationship table, filter out the ports directly connected to the abnormal port, extract and store their current data, and calculate the current difference ΔI between the adjacent port and the abnormal port. The calculation formula is as follows:

[0098] ΔI=I adj -I anom ;

[0099] Among them, I adj Represents the current value of the adjacent port, I anom Represents the current value of the abnormal port;

[0100] If the current value of the abnormal port is 12A and the current value of the adjacent port is 14A, then:

[0101] ΔI = 14-12 = 2A;

[0102] If the difference exceeds the set threshold T I , then the adjacent port is recorded and marked as the affected port, and the current difference threshold T is set I =1.5A, if the calculated difference is 2A, which is greater than 1.5A, the adjacent port is recorded, the marked adjacent port information is stored, and the adjacent port current data is obtained.

[0103] The load capacity identification submodule calculates the load capacity values ​​of multiple ports based on the adjacent port current data, analyzes the ratio of the port current carrying capacity to the port rated load value, analyzes the impact of the abnormal port on the adjacent port according to the power flow distribution, and obtains the fault impact range identification result;

[0104] Calculate the load capacity value of each port. The load capacity value is defined as the ratio of the port current carrying capacity to the port rated load value. The calculation formula is as follows:

[0105]

[0106] Among them, I iis the actual current value of the port, I rated is the rated load value of the port;

[0107] If the actual current value of a port is 18A and the rated load value is 20A, then the load capacity value of the port is:

[0108]

[0109] Analyze the power flow distribution and calculate the impact of abnormal ports on adjacent ports. i Calculated by power distribution ratio:

[0110]

[0111] Among them, P adj is the power of the adjacent port, P total is the total power of the abnormal port and adjacent ports;

[0112] If the power of the abnormal port is 5kW and the power of the adjacent port is 8kW, the impact is:

[0113]

[0114] Set the impact threshold T F , if F i >T F , then the port is greatly affected by the abnormal port, and the impact threshold is set to 0.6. If the calculated F i =0.615, it indicates that the adjacent ports are greatly affected by the abnormal port, the affected port information is stored, and the fault impact range identification result is obtained.

[0115] The partition isolation submodule uses the fault impact range identification result to calculate the load capacity value of the port and sort the priorities. The priority ones are used as the isolation boundaries to isolate the power supply channel of the fault point, determine the optimal partition position, and obtain the optimal partition isolation boundary.

[0116] The formula for calculating the load capacity value of a port is:

[0117]

[0118] Among them, P b Represents the load capacity value, L i Represents the power demand of the i-th load device, W i Represents the load weight of the i-th load device, I j Represents the real-time current of the jth power supply channel, I avg Represents the average current of the power supply channel, V k represents the voltage at the kth isolation boundary, V refrepresents the reference voltage, n represents the total number of load devices, m represents the total number of power supply channels, and p represents the total number of isolation boundary locations;

[0119] Parameter meaning and calculation process:

[0120] Power demand of load equipment L i The power demand is measured in real time by power monitoring equipment. The power demand is calculated based on the operating power of the load equipment. The power demand of 5 devices in a certain area is measured respectively:

[0121] L 1 =4.5kW, L 2 =3.8kW, L 3 =5.2kW, L 4 =4.1kW, L 5 =3.9kW;

[0122] Load weight W of the load device i According to the operation priority setting of the equipment, the higher the priority, the greater the weight. Based on the actual load scheduling strategy, the settings are as follows:

[0123] W 1 =1.2,W 2 =1.0,W 3 =1.5,W 4 =1.1,W 5 =1.0;

[0124] Calculate the numerator part:

[0125]

[0126] The actual current I of the power supply channel j The current transformer was used to measure the four power supply channels, and the data obtained are as follows:

[0127] I 1 =32A, I 2 =30A, I 3 =28A, I 4 =35A;

[0128] Calculate the average current I of the power supply channel avg :

[0129]

[0130] Calculate the first term in the denominator:

[0131]

[0132] The voltage at the isolation boundary V kThe voltage data of the three isolation boundary points were measured by voltage monitoring equipment as follows:

[0133] V 1 =220V, V 2 =215V, V 3 =225V;

[0134] Reference voltage V ref Set to 218V;

[0135] Calculate the second term in the denominator:

[0136]

[0137] Calculate the sum of the denominators:

[0138] 5.17+12=17.17;

[0139] Calculate the load capacity value P b :

[0140]

[0141] The result shows that the load capacity value is 1.48, which reflects the trade-off between the power demand of the load device under the current power supply channel current deviation and the isolation boundary voltage deviation. This value is used to isolate the power supply channel at the fault point and determine the optimal partition location.

[0142] Specifically, if Figure 2 , 5 As shown, the load adjustment module includes:

[0143] The power loss calculation submodule uses the optimal partition isolation boundary, records the power loss information of the isolated port, analyzes the power gap of the isolated port, and obtains the power loss record of the isolated port;

[0144] Record the power loss information of the isolated port and determine the power output P of the isolated port iso , and calculate the power loss P loss , the calculation formula is as follows:

[0145] P loss =P iso -P backup ;

[0146] Among them, P backup Represents the power provided by the backup power source or multiple paths after isolation;

[0147] The original power of an isolated port is 10 kW. After isolation, the backup path provides 3 kW. The power loss is:

[0148] Ploss =10-3=7;

[0149] The power losses of all isolated ports are calculated in sequence to form an isolated port power loss record.

[0150] The power margin judgment submodule calculates the power margin value of the port that is still in operation based on the power loss record of the isolated port, compares the power margin value with the power loss value, determines whether the power margin meets the compensation requirement, screens the ports whose power margin exceeds the compensation requirement, and obtains the compensation power port set;

[0151] Calculate the power headroom value P of the ports that are still in operation avail , the calculation formula is as follows:

[0152] P avail =P rated -P used ;

[0153] Among them, P rated is the rated power of the port, P used is the current operating power;

[0154] If the rated power of a port is 20kW and the current operating power is 12kW, then its power margin is:

[0155] P avail =20-12=8;

[0156] Compare the power margin and power loss. If P avail ≥P loss , then the port can provide compensation. If the power loss of an isolated port is 7kW and the power margin of a port is 8kW, then the port meets the compensation conditions, and the ports that meet the conditions form a compensation power port set.

[0157] The allocation ratio adjustment submodule uses the compensation power port set to screen the ports whose loads are close to the fault point, calculates the compensation power, adjusts the compensation allocation ratio, and obtains the power compensation allocation result;

[0158] The formula for calculating the compensation power is:

[0159]

[0160] Among them, Z c,o represents the compensation power at port o, Z d,a Represents the required power of load port a, Z f,a Represents the mismatch power of port a at the fault point, W a,o represents the weight coefficient between port a and port o, and N represents the total number of load ports;

[0161] Parameter meaning and formula calculation process:

[0162] Determine the required power Z of the load port d,a :By monitoring the actual power demand of each load port, Z d,a The value of , there are three load ports, and their required power is Z d,1 =50kW, Z d,2 =60kW, Z d,3 =55kW;

[0163] Determine the mismatch power Z at the fault point f,a :By detecting the actual output power of each port at the fault point, we can obtain Z f,a The corresponding mismatch power is set to Z f,1 =45kW, Z f,2 =65kW, Z f,3 =50kW;

[0164] Calculate the absolute value of the difference between the required power and the mismatch power:

[0165] For port 1: |Z d,1 -Z f,1 |=|50-45|=5kW;

[0166] For port 2: |Z d,2 -Z f,2 |=|60-65|=5kW;

[0167] For port 3: |Z d,3 -Z f,3 |=|55-50|=5kW;

[0168] Determine the weight coefficient W a,o : Set the weight coefficient according to factors such as the physical distance between ports and transmission efficiency. The weight coefficient is set based on:

[0169] Physical distance: The closer the distance, the greater the weight;

[0170] Transmission efficiency: The higher the transmission efficiency, the greater the weight;

[0171] Equipment capacity: The larger the equipment capacity, the greater the weight;

[0172] Set the weight coefficients as follows:

[0173] W 1,o =0.9,W 2,o =0.8,W 3,o =0.85;

[0174] Calculate the numerator part:

[0175]

[0176] Calculate the denominator:

[0177]

[0178] Calculate the compensation power Z c,o :

[0179]

[0180] The result shows that the compensation power of port o should be 5 to balance the difference between the demand power and the mismatch power at the fault point. The calculation result can be used to further adjust the power dispatch of the power grid or equipment to maintain the stability of power distribution.

[0181] Specifically, if Figure 2 , 6 As shown, the harmonic feature detection module includes:

[0182] The harmonic amplitude and phase extraction submodule uses the power compensation allocation results to extract the harmonic current signals of multiple ports in the AC microgrid, extracts the amplitude information from the harmonic current signals, records the amplitude and phase distribution corresponding to the multiple ports, and obtains the port harmonic amplitude and phase data;

[0183] Extract the harmonic current signals of multiple ports in the AC microgrid, perform spectrum analysis on the port current through a high-precision harmonic analyzer or Fourier transform (FFT) algorithm, and extract the amplitude and phase of each harmonic component. The harmonic current signal can be expressed as:

[0184]

[0185] Among them, I 0 is the fundamental current, I n is the amplitude of the nth harmonic component, ω is the fundamental angular frequency, φ n is the phase of the corresponding harmonic;

[0186] The system collects the harmonic amplitude and phase data of each port. If the harmonic analysis result of a port is: fundamental wave 50Hz amplitude 10A, phase 0°, 3rd harmonic (150Hz) amplitude 2A, phase 30°, 5th harmonic (250Hz) amplitude 1.5A, phase 45°;

[0187] The harmonic amplitude and phase data of the port are stored as:

[0188] I 3 =2A,φ 3 =30°;

[0189] I 5 =1.5A,φ 5 =45°;

[0190] All port data are recorded and organized into port harmonic amplitude and phase data.

[0191] The harmonic matching comparison submodule identifies the harmonic amplitude and phase of the breakpoint port based on the port harmonic amplitude and phase data, compares the harmonic amplitude and phase data of the port with the harmonic amplitude and phase data of the breakpoint port, selects ports with similar amplitudes, and obtains the port harmonic matching results;

[0192] Identify the harmonic characteristics of the breakpoint port, obtain its harmonic amplitude and phase information, compare the data of all ports, filter out ports with similar amplitudes, and calculate the harmonic amplitude matching degree M:

[0193]

[0194] Among them, I ref is the harmonic amplitude of the breakpoint port, I test is the harmonic amplitude of the port to be matched;

[0195] If the 3rd harmonic amplitude of the breakpoint port is 2A and the 3rd harmonic amplitude of a certain port is 1.9A, the matching degree is calculated as follows:

[0196]

[0197] Set the matching threshold T M , if M>T M , then filter the port as a candidate matching port and set T M =0.9, if the calculated matching degree of a port is 0.95, the port is selected to obtain the port harmonic matching result.

[0198] The priority screening submodule screens the ports with priority matching through the port harmonic matching results, combines the harmonic data of the matching ports with the breakpoint port data, performs iterative verification, selects the ports with priority matching as the reconnection ports, and obtains the harmonic matching reconnection ports;

[0199] Filter the ports with the highest matching degree and calculate the comprehensive matching score S of the matching ports:

[0200] S=w 1 M+w 2 |φ ref -φ test |;

[0201] Among them, w 1 and w 2 is the matching weight, φ ref and φ test is the phase between the breakpoint port and the matching port;

[0202] If the weight w1 =0.7, w 2 =0.3, the matching degree of a port M = 0.95, the phase difference |φ ref -φ test |=5°, then:

[0203] S=0.7×0.95+0.3×5=1.015;

[0204] The port with the highest score is selected as the priority reconnection port, and combined with iterative verification, the changes in the harmonic data of the new matching port and the breakpoint port data are compared. If the matching degree of the new matching port still meets the threshold requirement, the port is selected as the harmonic matching reconnection port to obtain the harmonic matching reconnection port.

[0205] Specifically, if Figure 2 , 7 As shown, the phase synchronization module includes:

[0206] The target port voltage adjustment submodule reconnects the port based on harmonic matching, records the voltage and voltage amplitude of the target port, adjusts the voltage amplitude of the target port to a set range, and matches it with the voltage amplitude of the fault point to obtain a target port voltage matching record;

[0207] Record the voltage and voltage amplitude of the target port, and use the voltage monitoring device to obtain the real-time voltage amplitude U of the target port. target and compare it with the set range. If the voltage exceeds the set range, it will be adjusted to set the target voltage range to [U min ,U max ], the adjustment formula is as follows:

[0208] U adj =U target +K v (U ref -U target );

[0209] Among them, K v is the voltage regulation factor, U ref To set the target voltage value;

[0210] If the current voltage amplitude of the target port is 218V, set the target voltage to 220V, and adjust the coefficient K v =0.5, then the adjusted voltage amplitude is calculated as follows:

[0211] U adj =218+0.5×(220-218)=219;

[0212] After the calculation is completed, the port voltage is adjusted. If the adjusted voltage still does not reach the set range, it is further adjusted until it meets the requirements and matches the voltage amplitude of the fault point to obtain the target port voltage matching record.

[0213] The phase consistency judgment submodule uses the target port voltage matching record to extract the phase information of the target port, compares the phase information of the target port with the phase data of the fault point, identifies the range of the phase deviation, and obtains the target port phase deviation identification result;

[0214] Extract the phase information φ of the target port target , and the phase data φ of the fault point fault For comparison, calculate the phase deviation Δφ:

[0215] Δφ=|φ target -φ fault |;

[0216] If the target port phase is 30° and the fault point phase is 25°, the phase deviation is calculated as follows:

[0217] Δφ=|30-25|=5°;

[0218] Set the phase deviation threshold T φ , if Δφ>T φ , then the target port needs to be adjusted, and the phase deviation threshold is set to 3°. If the calculated deviation is 5°, the port phase deviation is marked as exceeding the standard, and the target port phase deviation identification result is obtained.

[0219] The phase synchronization control submodule uses the target port phase deviation identification result to adjust the phase of the target port, evaluate the consistency with the fault point phase, record the phase adjustment state of the AC microgrid target port, and obtain the AC microgrid phase control result;

[0220] Adjust the phase of the target port to keep it consistent with the phase of the fault point. The adjustment adopts phase compensation. The adjustment formula is as follows:

[0221] φ adj =φ target +K φ (φ fault -φ target );

[0222] Among them, K φ is the phase adjustment coefficient. If the target port phase is 30° and the fault point phase is 25°, the adjustment coefficient K φ =0.6, then the phase adjustment is calculated as follows:

[0223] φ adj =30+0.6×(25-30)=27°;

[0224] After adjustment, the phase of the target port is remeasured. If the deviation still exceeds the set threshold, the adjustment is continued until the synchronization requirement is met. The state of the target port phase after adjustment is recorded, and the AC microgrid phase control result is output.

[0225] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An AC microgrid system based on a multi-port AC substation, characterized in that: The system comprises: The port current fluctuation detection module collects the amplitude, phase and frequency data of the port current signal, determines whether the current is abnormal, analyzes the current amplitude, phase and frequency fluctuations by setting thresholds, screens abnormal ports, and obtains abnormal port identification data; The dynamic partitioning module screens the current data of adjacent ports based on the abnormal port identification data, identifies the load capacity of multiple ports, evaluates the impact range of the fault point according to the power flow distribution, performs partition isolation, selects the load port as the isolation boundary, and generates the optimal partition isolation boundary; The load adjustment module records the power loss of the isolated port of the AC microgrid through the optimal partition isolation boundary, calculates the power margin of the port that is still in operation, determines whether the power margin is sufficient to compensate for the load loss of the isolated port, selects the port whose load is close to the fault point for power compensation, and obtains the power compensation allocation result; The harmonic feature detection module uses the power compensation allocation result to identify the amplitude and phase distribution of the harmonics, evaluate the harmonic matching degree between the reconnection port and the breakpoint, select the ports close to the breakpoint harmonics for reconnection, and generate the harmonic matching reconnection port.

2. The AC microgrid system based on a multi-port AC substation according to claim 1, characterized in that: The abnormal port identification data includes abnormal current amplitude identification information, abnormal phase deviation record, and frequency mutation data; the optimal partition isolation boundary includes load capacity assessment data, fault point impact range assessment results, and partition isolation information; the power compensation allocation result includes power loss data, power margin, and power compensation allocation record; the harmonic matching reconnection port includes the identified harmonic amplitude, phase distribution data, reconnection port harmonic matching assessment results, and the selected harmonic matching reconnection port identification.

3. The AC microgrid system based on a multi-port AC substation according to claim 1, characterized in that: The port current fluctuation detection module comprises: The current signal acquisition submodule collects the amplitude, phase and frequency data of the port current signal, calculates the current amplitude change, phase change and frequency change during continuous time, arranges them in time series, and obtains current change sequence data; The amplitude-phase analysis submodule calculates the amplitude change rate, phase offset and frequency fluctuation rate through the current change sequence data, compares the amplitude change rate with the amplitude threshold, the phase offset with the phase threshold, filters out the signals exceeding the threshold, identifies the fluctuation degree in combination with the frequency fluctuation rate, and obtains the current fluctuation characteristic parameters; The abnormal port screening submodule uses the current fluctuation characteristic parameters and refers to the port fluctuation degree to compare the normal port with the abnormal port, identifies the deviation degree, records the abnormal port number, and obtains abnormal port identification data.

4. The AC microgrid system based on a multi-port AC substation according to claim 1, characterized in that: The dynamic partitioning module comprises: The adjacent port screening submodule uses the abnormal port identification data to screen the port current data adjacent to the abnormal port, calculates the current difference between the adjacent ports, records the adjacent port numbers, and obtains the adjacent port current data; The load capacity identification submodule calculates the load capacity values ​​of multiple ports based on the adjacent port current data, analyzes the ratio of the port current carrying capacity to the port rated load value, analyzes the influence of the abnormal port on the adjacent port according to the power flow distribution, and obtains the fault impact range identification result; The partition isolation submodule uses the fault impact range identification result to calculate the load capacity value of the port, and prioritizes it, uses the prioritized port as the isolation boundary, isolates the power supply channel of the fault point, determines the optimal partition position, and obtains the optimal partition isolation boundary.

5. The AC microgrid system based on a multi-port AC substation according to claim 4, characterized in that: The formula for calculating the load capacity value of the port is: Among them, P b Represents the load capacity value, L i Represents the power demand of the i-th load device, W i Represents the load weight of the i-th load device, I j Represents the real-time current of the jth power supply channel, I avg Represents the average current of the power supply channel, V k represents the voltage at the kth isolation boundary, V ref represents the reference voltage, n represents the total number of load devices, m represents the total number of power supply channels, and p represents the total number of isolation boundary locations.

6. The AC microgrid system based on a multi-port AC substation according to claim 1, characterized in that: The load adjustment module comprises: The power loss calculation submodule adopts the optimal partition isolation boundary, records the power loss information of the isolated port, analyzes the power gap of the isolated port, and obtains the power loss record of the isolated port; The power margin judgment submodule calculates the power margin value of the port that is still in operation based on the power loss record of the isolated port, compares the power margin value with the power loss value, determines whether the power margin meets the compensation requirement, screens the ports whose power margin exceeds the compensation requirement, and obtains the compensation power port set; The allocation ratio adjustment submodule uses the compensation power port set to screen ports whose loads are close to the fault point, calculate the compensation power, adjust the compensation allocation ratio, and obtain the power compensation allocation result.

7. The AC microgrid system based on a multi-port AC substation according to claim 6, characterized in that: The formula for calculating the compensation power is: Among them, Z c,o represents the compensation power at port o, Z d,a Represents the required power of load port a, Z f,a Represents the mismatch power of port a at the fault point, W a,o represents the weight coefficient between port a and port o, and N represents the total number of load ports.

8. The AC microgrid system based on a multi-port AC substation according to claim 1, characterized in that: The harmonic feature detection module comprises: The harmonic amplitude and phase extraction submodule uses the power compensation allocation result to extract the harmonic current signals of multiple ports in the AC microgrid, extracts the amplitude information from the harmonic current signals, records the amplitude and phase distribution corresponding to the multiple ports, and obtains the port harmonic amplitude and phase data; The harmonic matching comparison submodule identifies the harmonic amplitude and phase of the breakpoint port based on the port harmonic amplitude and phase data, compares the harmonic amplitude and phase data of the port with the harmonic amplitude and phase data of the breakpoint port, selects ports with similar amplitudes, and obtains the port harmonic matching result; The priority screening submodule screens the ports with priority matching through the port harmonic matching results, combines the harmonic data of the matching ports with the breakpoint port data, performs iterative verification, selects the ports with priority matching as the reconnection ports, and obtains the harmonic matching reconnection ports.

9. The AC microgrid system based on a multi-port AC substation according to claim 1, characterized in that: The system also includes a phase synchronization module: The phase synchronization module reconnects the port based on the harmonic matching, records the voltage of the target port, adjusts the voltage amplitude, matches it with the fault point, determines the consistency of the phase of the newly connected port with the phase of the fault point, and generates the AC microgrid phase control result by adjusting the phase of the new port to synchronize with the fault point; The AC microgrid phase control result includes adjusted voltage amplitude data, a phase matching evaluation result between a new access port and a fault point, and phase control information.

10. The AC microgrid system based on a multi-port AC substation according to claim 9, characterized in that: The phase synchronization module comprises: The target port voltage adjustment submodule records the voltage and voltage amplitude of the target port based on the harmonic matching reconnection port, adjusts the voltage amplitude of the target port to a set range, and matches it with the voltage amplitude of the fault point to obtain a target port voltage matching record; The phase consistency judgment submodule uses the target port voltage matching record to extract the phase information of the target port, compares the phase information of the target port with the phase data of the fault point, identifies the range of the phase deviation, and obtains the target port phase deviation identification result; The phase synchronization control submodule uses the target port phase deviation identification result to adjust the phase of the target port, evaluate the consistency with the fault point phase, record the phase adjusted state of the AC microgrid target port, and obtain the AC microgrid phase control result.

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