Direct-current bus connection state monitoring system of solar photovoltaic module

Abstract

The invention belongs to the technical field of electric power supervision, and particularly relates to a direct current bus connection state monitoring system of a solar photovoltaic module, which comprises a monitoring platform, a connection part exclusive analysis module, a point division type monitoring module, a direct current bus state evaluation module and a background terminal, according to the invention, analysis is carried out through the connection part exclusive analysis module so as to determine an abnormal connection part and give a corresponding connection judgment symbol, and the point-division monitoring module carries out point-division monitoring analysis on the DC bus so as to give a corresponding bus judgment symbol. The direct current bus state evaluation module comprehensively analyzes and accurately judges the direct current bus connection state and the operation risk of the solar photovoltaic module based on the connection judgment symbol and the bus judgment symbol, and reminds a manager to take improvement treatment measures when a direct current bus state difference signal is generated, so that the intelligent degree is high; and safe and stable operation of the DC bus is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of power supervision, and in particular to a DC bus connection state monitoring system for a solar photovoltaic assembly. Background Art

[0002] Solar photovoltaic modules are composed of high-efficiency crystalline silicon solar cells, back panels and frames, and are mainly used for photovoltaic power generation. Photovoltaic power generation does not emit noise or pollutants, and the application technology is mature, safe and reliable. Solar energy is the cleanest, safest and most reliable energy in the future. The photovoltaic industry is increasingly becoming another explosively developing industry after the IT and microelectronics industries.

[0003] In photovoltaic power generation systems, the connection status of the DC bus directly affects its safety and stability. At present, it is difficult to reasonably analyze and comprehensively evaluate the operation and connection status of the DC bus of solar photovoltaic modules, and it is impossible to accurately feedback the surface hidden dangers of the DC bus, and it is impossible to timely warn of the safety hazards of the DC bus, which is not conducive to ensuring the safe and stable operation of the DC bus, and the degree of intelligence is low;

[0004] In view of the above technical defects, a solution is now proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a DC bus connection status monitoring system for a solar photovoltaic module, which solves the problems that the prior art is difficult to reasonably analyze and comprehensively evaluate the operating connection status of the DC bus of the solar photovoltaic module, cannot accurately feedback the surface hidden danger status of the DC bus, cannot provide timely warning of the safety hazards of the DC bus, and has a low level of intelligence.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The DC bus connection status monitoring system of solar photovoltaic modules includes a monitoring platform, a connection abnormality analysis module, a point-by-point monitoring module, a DC bus status assessment module and a background terminal;

[0008] The connection abnormality analysis module obtains all bus connections existing on the DC bus of the solar photovoltaic module, marks the corresponding bus connection as the target connection i, where i is a natural number greater than 1; determines the abnormal connection through analysis and assigns a connection judgment symbol LP-1 or LP-2, and sends the connection judgment symbol LP-1 or LP-2 to the DC bus state assessment module;

[0009] The point-by-point monitoring module performs point-by-point monitoring and analysis on the DC bus, assigns a bus judgment symbol GP-1 or GP-2 through analysis, and sends the bus judgment symbol GP-1 or GP-2 to the DC bus state evaluation module;

[0010] The DC bus state assessment module performs intersection analysis on the connection judgment symbol and the bus judgment symbol. If LP-2∩GP-2 is obtained, a DC bus state qualified signal is generated. In other cases, a DC bus state abnormal signal is generated, and the DC bus state qualified signal or the DC bus state abnormal signal is sent to the background terminal via the monitoring platform. The background terminal issues an early warning when receiving the DC bus state abnormal signal.

[0011] Furthermore, the specific operation process of the connection analysis module includes:

[0012] The fastening force applied by the connector at the target connection i to the DC bus is obtained and marked as the connection force measurement value, and the deviation value of the connection force measurement value compared to the standard connection force measurement value is marked as the connection force deviation value; and the real-time busbar joint contact resistance at the target connection i is collected and marked as the contact resistance actual measurement value, and the contact resistance trend value of the target connection i is obtained through contact resistance trend analysis;

[0013] The connection anomaly value is obtained by numerically calculating the connection force deviation, the measured contact resistance value and the contact resistance trend value. The connection anomaly value is numerically compared with the preset connection anomaly threshold. If the connection anomaly value exceeds the preset connection anomaly threshold, the target connection i is marked as an abnormal connection; if there is an abnormal connection, the connection judgment symbol LP-1 is assigned; if there is no abnormal connection, the connection judgment symbol LP-2 is assigned.

[0014] Furthermore, the specific analysis process of contact resistance trend analysis is as follows:

[0015] A rectangular coordinate system located in the first quadrant is established with time as the X-axis and the busbar joint contact resistance as the Y-axis, and a contact resistance curve is drawn in the rectangular coordinate system based on the contact resistance of all busbar joints at the target connection i per unit time; a number of coordinate points are marked on the contact resistance curve and defined as verification points, and the X-direction distances between two adjacent verification points are the same;

[0016] And in the rectangular coordinate system, a ray parallel to the X-axis and with its endpoint on the Y-axis is drawn and marked as the resistance verification ray, and the number of verification points located above the resistance verification ray in the rectangular coordinate system is counted and marked as verification number outliers;

[0017] The verification point located above the resistance verification ray is marked as an abnormal verification point, a line segment perpendicular to the resistance verification ray is made with the corresponding abnormal verification point as the endpoint and marked as a core distance line segment, the length of the core distance line segment is marked as the core distance value, and the core distance values ​​of all abnormal verification points are averaged to obtain the verification excess value, and the X-direction length and value involved in the rising part of the contact resistance curve are obtained and marked as the contact resistance increase time value; the contact resistance trend value is obtained by numerically calculating the verification number abnormal value, the verification excess value and the contact resistance increase time value.

[0018] Furthermore, the specific operation process of the point-by-point monitoring module includes:

[0019] A number of monitoring points are set on the DC bus of the solar photovoltaic module, and the real-time voltage and real-time current of all monitoring points are collected. The variance of the real-time voltage of all monitoring points is calculated to obtain the bus voltage value, and the variance of the real-time current of all monitoring points is calculated to obtain the bus current value. The bus voltage value and the bus current value are numerically compared with the preset bus voltage threshold and the preset bus current threshold, respectively. If the bus voltage value or the bus current value exceeds the corresponding preset threshold, the bus judgment symbol GP-1 is assigned.

[0020] Further, if the bus voltage value and the bus current value do not exceed the corresponding preset threshold value, the bus point condition value of the corresponding monitoring point is obtained by analysis, the bus point condition values ​​of all monitoring points are averaged to obtain the bus point measurement value, and the bus point condition value is numerically compared with the preset bus point condition threshold value, and the number of bus point condition values ​​exceeding the preset bus point condition threshold value is marked as bus outlier value, and the bus point condition value with the largest value is marked as bus point amplitude;

[0021] The bus abnormal value is obtained by numerically calculating the bus point measurement value, the bus abnormal point value and the bus point amplitude, and the bus abnormal value is numerically compared with the preset bus abnormal threshold. If the bus abnormal value exceeds the preset bus abnormal threshold, the bus judgment symbol GP-1 is assigned; if the bus abnormal value does not exceed the preset bus abnormal threshold, the bus judgment symbol GP-2 is assigned.

[0022] Furthermore, the specific analysis process of obtaining the busbar point condition value of the corresponding monitoring point through analysis is as follows:

[0023] The deviation value of the real-time voltage of the corresponding monitoring point compared to the median of the preset suitable voltage range is marked as the bus point voltage value, the deviation value of the real-time current of the corresponding monitoring point compared to the median of the preset suitable current range is marked as the bus point current value, and the real-time temperature of the corresponding monitoring point is collected and marked as the bus point temperature value; the bus point condition value is obtained by numerically calculating the bus point voltage value, the bus point current value and the bus point temperature value.

[0024] Furthermore, the monitoring platform is communicatively connected to the DC bus scanning decision module, and the monitoring platform sends a DC bus status qualified signal to the DC bus scanning decision module. When the DC bus scanning decision module receives the DC bus status qualified signal, it collects the surface image of the DC bus, analyzes the surface quality condition of the DC bus based on the surface image, generates a DC bus scanning qualified signal or a DC bus scanning abnormal signal through analysis, and sends the DC bus scanning qualified signal or the DC bus scanning abnormal signal to the background terminal via the monitoring platform. When the background terminal receives the DC bus scanning abnormal signal, it issues an early warning.

[0025] Furthermore, the specific analysis process of the DC bus scanning decision module is as follows:

[0026] Based on the scanning image of the DC bus, whether the surface of the DC bus is damaged is judged, and if the surface of the DC bus is damaged, a DC bus scanning abnormality signal is generated;

[0027] If there is no damage on the surface of the DC bus, the deviation value of the real-time distance value at the corresponding two positions on the DC bus compared to the corresponding initial distance value is collected and marked as the spacing deviation value, the average of all spacing deviation values ​​on the DC bus is marked as the spacing deviation table value, and the number of spacing deviation values ​​exceeding the preset spacing deviation threshold is marked as the spacing deviation value, the spacing deviation table value and the spacing deviation value are numerically compared with the preset spacing deviation table threshold and the preset spacing deviation threshold, respectively; if the spacing deviation table value or the spacing deviation value exceeds the corresponding preset threshold, a DC bus scanning abnormality signal is generated.

[0028] Furthermore, if both the spacing deviation table value and the spacing deviation value do not exceed the corresponding preset threshold value, the scanned image of the DC bus is gray-processed, and the real-time gray-scale values ​​of all positions on the DC bus are collected. A number of areas are set on the DC bus, and the total area of ​​the corresponding area whose actual gray-scale value exceeds the preset gray-scale threshold value is marked as a non-clean surface measurement value, and all the real-time gray-scale values ​​of the corresponding area are averaged to obtain a gray-scale inspection value, and the non-clean surface measurement value and the gray-scale inspection value are numerically compared with the preset non-clean surface measurement threshold value and the preset gray-scale inspection threshold value. If the non-clean surface measurement value or the gray-scale inspection value exceeds the corresponding preset threshold value, the corresponding area is marked as a non-clean area;

[0029] If there is a non-clean area on the DC bus, a DC bus scanning abnormal signal is generated; if there is no non-clean area on the DC bus, the non-clean surface measurement values ​​of all areas on the DC bus are summed up to obtain the non-clean surface analysis value, the grayscale inspection values ​​of all areas are averaged to obtain the grayscale inspection value, the bus cleanliness value is obtained by numerically calculating the non-clean surface analysis value and the grayscale inspection value, the bus cleanliness value is numerically compared with the preset bus cleanliness threshold, if the bus cleanliness value exceeds the preset bus cleanliness threshold, a DC bus scanning abnormal signal is generated; if the bus cleanliness value does not exceed the preset bus cleanliness threshold, a DC bus scanning qualified signal is generated.

[0030] Furthermore, each or multiple solar photovoltaic modules are connected to an SMP Unit to form a photovoltaic module group; several photovoltaic module groups are connected in parallel to a DC bus, and then connected to the energy device through the DC bus.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. In the present invention, the abnormal connection is determined by analyzing the connection abnormality analysis module and assigning corresponding connection judgment symbols. The point-by-point monitoring module performs point-by-point monitoring and analysis on the DC bus to assign corresponding bus judgment symbols. The DC bus state assessment module comprehensively analyzes and accurately judges the DC bus connection state and operation risk of the solar photovoltaic module based on the connection judgment symbols and bus judgment symbols. The module has a high degree of intelligence and is conducive to ensuring the safe and stable operation of the DC bus.

[0033] 2. In the present invention, the DC bus status qualified signal is sent to the DC bus scanning decision module through the monitoring platform. The DC bus scanning decision module collects the surface image of the DC bus, analyzes its surface quality condition based on the surface image of the DC bus, and enables the background terminal to issue an early warning when the DC bus scanning abnormal signal is generated. It can reasonably analyze and accurately judge the surface abnormality of the DC bus, and promptly remind the management personnel to take corresponding improvement measures, thereby further reducing the use risk of the DC bus. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to facilitate understanding by those skilled in the art, the present invention is further described below in conjunction with the accompanying drawings;

[0035] Figure 1 This is a system block diagram of Embodiment 1 of the present invention;

[0036] Figure 2 This is a system block diagram of Embodiment 2 of the present invention;

[0037] Figure 3 This is a structural block diagram of Embodiment 3 of the present invention;

[0038] Figure 4 for Figure 3 A magnified view of part A;

[0039] Figure 5 for Figure 3 Enlarged view of part B. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Embodiment 1: Figure 1 As shown, the DC bus connection status monitoring system of the solar photovoltaic module proposed in the present invention includes a monitoring platform, a connection abnormality analysis module, a point-by-point monitoring module, a DC bus status evaluation module and a background terminal;

[0042] Among them, the connection analysis module obtains all bus connections existing on the DC bus of the solar photovoltaic module. It should be noted that the bus connection is an important part of the DC bus connecting different mother devices or cables. The bus connection is usually composed of a bus body, connectors, etc.; the corresponding bus connection is marked as the target connection i, and i is a natural number greater than 1;

[0043] By analyzing to determine the abnormal connection and assigning the connection judgment symbol LP-1 or LP-2, and sending the connection judgment symbol LP-1 or LP-2 to the DC bus state assessment module, not only can the safety risk status of each bus connection be reasonably assessed to remind the management personnel to take corresponding treatment measures, but also information support can be provided for the analysis process of the DC bus state assessment module to ensure the accuracy of its analysis results; the specific operation process of the connection abnormality analysis module is as follows:

[0044] The tightening force applied by the connector at the target connection i to the DC bus is obtained and marked as the connection force measurement value, and the deviation of the connection force measurement value from the standard connection force measurement value is marked as the connection force deviation value; wherein, the tightening force of the connector needs to be moderate, too tight may easily cause deformation or damage of the bus, and too loose may easily cause poor contact or looseness;

[0045] The real-time busbar joint contact resistance of the target connection i is collected and marked as the contact resistance measured value; wherein the busbar joint contact resistance refers to the resistance generated at the busbar connection due to poor contact between the conductor and the connected conductor. The larger the value of the busbar joint contact resistance, the greater the safety risk of the corresponding busbar connection;

[0046] And obtaining the contact resistance trend value of the target connection i through contact resistance trend analysis, specifically: establishing a rectangular coordinate system located in the first quadrant with time as the X-axis and the busbar joint contact resistance as the Y-axis, and drawing a contact resistance curve in the rectangular coordinate system based on all busbar joint contact resistances of the target connection i per unit time; marking a number of coordinate points on the contact resistance curve and defining them as verification points, and the X-direction distances between two adjacent verification points are the same;

[0047] And in the rectangular coordinate system, a ray parallel to the X-axis and with its endpoint on the Y-axis is made and marked as a resistance verification ray. It should be noted that the value of the Y-axis coordinate corresponding to the resistance verification ray is the preset busbar joint contact resistance threshold, and the value of the preset busbar joint contact resistance threshold is greater than zero; the number of verification points located above the resistance verification ray in the rectangular coordinate system is counted and marked as verification number outliers;

[0048] The verification point located above the resistance verification ray is marked as an abnormal verification point, a line segment perpendicular to the resistance verification ray is made with the corresponding abnormal verification point as the endpoint and marked as a core distance line segment, the length of the core distance line segment is marked as the core distance value, and the core distance values ​​of all abnormal verification points are averaged to obtain the verification excess value, and the X-direction length and value involved in the rising part of the contact resistance curve are obtained and marked as the contact resistance increase time value;

[0049] The contact resistance trend value TXi is obtained by numerically calculating the verification numerical abnormal value TPi, the verification over-inspection value TYi and the contact resistance increase time value TWi through the formula TXi=nk1*TPi+(nk2*TYi+nk3*TWi) / nk1; wherein nk1, nk2 and nk3 are preset proportional coefficients with values ​​greater than zero, and the larger the value of the contact resistance trend value TXi is, the more abnormal the performance of the busbar joint contact resistance at the target connection i in unit time is, and the greater the safety risk is;

[0050] By formula The connection force deviation QLi, the measured contact resistance value QYi and the contact resistance trend value TXi are numerically calculated to obtain the connection anomaly value QKi; wherein rp1, rp2 and rp3 are preset proportional coefficients, and the values ​​of rp1, rp2 and rp3 are all positive numbers; and the larger the value of the connection anomaly value QKi is, the greater the safety risk of the target connection i is in general;

[0051] The connection abnormality value QKi is numerically compared with the preset connection abnormality threshold. If the connection abnormality value QKi exceeds the preset connection abnormality threshold, it indicates that the safety risk of the target connection i is relatively large, and the target connection i is marked as an abnormal connection; if there is an abnormal connection, it indicates that there is a safety hazard at the connection of the DC bus, and a connection judgment symbol LP-1 is assigned; if there is no abnormal connection, it indicates that there is no safety hazard at the connection of the DC bus, and a connection judgment symbol LP-2 is assigned.

[0052] The point-by-point monitoring module performs point-by-point monitoring and analysis on the DC bus, assigns the bus judgment symbol GP-1 or GP-2 through analysis, and sends the bus judgment symbol GP-1 or GP-2 to the DC bus status assessment module, which can not only reasonably judge the operating risk status of the DC bus itself, but also provide information support for the analysis process of the DC bus status assessment module, further ensuring the accuracy of its analysis results; the specific operation process of the point-by-point monitoring module is as follows:

[0053] A number of monitoring points are set on the DC bus of the solar photovoltaic module, and the real-time voltage and real-time current of all monitoring points are collected. The variance of the real-time voltage of all monitoring points is calculated to obtain the bus voltage value, and the variance of the real-time current of all monitoring points is calculated to obtain the bus current value. Among them, the larger the bus voltage value and the bus current value are, the more unstable the voltage and current on the DC bus are; the bus voltage value and the bus current value are numerically compared with the preset bus voltage threshold and the preset bus current threshold respectively. If the bus voltage value or the bus current value exceeds the corresponding preset threshold, it indicates that the self-operation risk of the DC bus is relatively large, and the bus judgment symbol GP-1 is assigned.

[0054] Furthermore, if the bus voltage value and the bus current value do not exceed the corresponding preset threshold value, the bus point condition value of the corresponding monitoring point is obtained by analysis, specifically: the deviation value of the real-time voltage of the corresponding monitoring point compared to the median of the preset suitable voltage range is marked as the bus point voltage value, the deviation value of the real-time current of the corresponding monitoring point compared to the median of the preset suitable current range is marked as the bus point current value, and the real-time temperature of the corresponding monitoring point is collected and marked as the bus point temperature value;

[0055] The bus point condition value PN is obtained by numerically calculating the bus point voltage value PY, the bus point current value PL and the bus point temperature value PW through the formula PN=(fu1*PY+fu2*PL+fu3*PW) / 3; wherein fu1, fu2 and fu3 are preset proportional coefficients with values ​​greater than zero, and the larger the value of the bus point condition value PN is, the greater the operating risk of the corresponding monitoring point on the DC bus;

[0056] The bus point condition values ​​of all monitoring points are averaged to obtain the bus point measurement value, and the bus point condition value is numerically compared with the preset bus point condition threshold, and the number of bus point condition values ​​exceeding the preset bus point condition threshold is marked as bus outlier value, and the bus point condition value with the largest value is marked as bus point amplitude;

[0057] The bus point measurement value WF, the bus point value WS and the bus point amplitude value WK are numerically calculated by the formula WY=hy2*WS+(hy1*WF+hy3*WK) / 2 to obtain the bus abnormal value WY; wherein hy1, hy2 and hy3 are preset proportional coefficients, hy2>hy1>hy3>0; and the larger the value of the bus abnormal value WY, the worse the state of the DC bus and the greater the operation risk;

[0058] The bus abnormal meter value WY is numerically compared with the preset bus abnormal meter threshold. If the bus abnormal meter value WY exceeds the preset bus abnormal meter threshold, it indicates that the overall operation risk of the DC bus is large, and the bus judgment symbol GP-1 is assigned; if the bus abnormal meter value WY does not exceed the preset bus abnormal meter threshold, it indicates that the overall operation risk of the DC bus itself is small, and the bus judgment symbol GP-2 is assigned.

[0059] The DC bus state evaluation module performs intersection analysis on the connection judgment symbol and the bus judgment symbol. If LP-2∩GP-2 is obtained, it indicates that the operation connection state of the DC bus is good, and a DC bus state qualified signal is generated. The rest of the cases (including LP-1∩GP-1, LP-1∩GP-2 and LP-2∩GP-1) indicate that the operation connection state of the DC bus is poor, and a DC bus state abnormal signal is generated.

[0060] The DC bus status qualified signal or DC bus status abnormal signal is sent to the background terminal through the monitoring platform. When the background terminal receives the DC bus status abnormal signal, it will issue an early warning. It can comprehensively analyze and accurately judge the DC bus connection status and operation risk of the solar photovoltaic module. It has a high degree of intelligence, which is conducive to the management personnel to make improvement measures in time to ensure the safe and stable operation of the DC bus.

[0061] Embodiment 2: Figure 2 As shown, the difference between this embodiment and embodiment 1 is that the monitoring platform is communicatively connected to the DC bus scanning decision module, the monitoring platform sends a DC bus state qualified signal to the DC bus scanning decision module, and the DC bus scanning decision module collects the surface image of the DC bus when receiving the DC bus state qualified signal, analyzes the surface quality of the DC bus based on the surface image of the DC bus, and generates a DC bus scanning qualified signal or a DC bus scanning abnormal signal through analysis;

[0062] The DC bus scan qualified signal or DC bus scan abnormal signal is sent to the background terminal through the monitoring platform. When the background terminal receives the DC bus scan abnormal signal, it issues an early warning, which can reasonably analyze and accurately judge the surface abnormality of the DC bus, and promptly remind the management personnel to take corresponding improvement measures, thereby ensuring the safe operation of the DC bus and reducing the use risk. The specific analysis process of the DC bus scan decision module is as follows:

[0063] Based on the scanning image of the DC bus, it is judged whether there is damage on its surface. If there is damage on the surface of the DC bus, it indicates that the use risk of the DC bus is relatively high, and a DC bus scanning abnormality signal is generated;

[0064] If there is no damage on the surface of the DC bus, the deviation value of the real-time distance value at the corresponding two positions on the DC bus compared to the corresponding initial distance value is collected and marked as the spacing deviation value, wherein the larger the value of the spacing deviation value is, the greater the probability of deformation between the corresponding two positions is; the average value of all spacing deviation values ​​on the DC bus is marked as the spacing deviation value, and the number of spacing deviation values ​​exceeding the preset spacing deviation threshold is marked as the spacing deviation value;

[0065] The spacing deviation table value and the spacing deviation value are numerically compared with the preset spacing deviation table threshold and the preset spacing deviation threshold respectively. If the spacing deviation table value or the spacing deviation value exceeds the corresponding preset threshold, it indicates that the deformation condition of the DC bus is abnormal and the use risk of the DC bus is relatively high, then a DC bus scanning abnormality signal is generated.

[0066] Furthermore, if both the spacing deviation table value and the spacing deviation value do not exceed the corresponding preset threshold value, indicating that the deformation condition of the DC bus is relatively normal, the scanned image of the DC bus is gray-scale processed, and the real-time gray-scale values ​​of all positions on the DC bus are collected. Several areas are set on the DC bus, and the total area of ​​the corresponding area whose actual gray-scale value exceeds the preset gray-scale threshold value is marked as a non-clean surface measurement value, and all the real-time gray-scale values ​​of the corresponding area are averaged to obtain the gray-scale inspection value;

[0067] Compare the non-clean surface measurement value and grayscale inspection value with the preset non-clean surface measurement threshold and the preset grayscale inspection threshold. If the non-clean surface measurement value or grayscale inspection value exceeds the corresponding preset threshold, indicating that the pollution condition of the corresponding area is serious, the corresponding area is marked as a non-clean area.

[0068] If there is a non-clean area on the DC bus, it indicates that the use risk of the DC bus is relatively high, and a DC bus scanning abnormal signal is generated; if there is no non-clean area on the DC bus, the non-clean surface measurement values ​​of all areas on the DC bus are summed up to obtain a non-clean surface analysis value, and the grayscale inspection values ​​of all areas are averaged to obtain a grayscale inspection value;

[0069] The bus cleanliness value MX is obtained by numerically calculating the unclean surface analysis value MS and the grayscale analysis value MK through the formula MX=a1*MS+a2*MK, wherein a1 and a2 are preset proportional coefficients with values ​​greater than zero, and the larger the value of the bus cleanliness value MX, the more serious the surface pollution of the DC bus, the greater the use risk of the DC bus, and the more timely inspection and treatment are needed;

[0070] The bus cleanliness value MX is numerically compared with the preset bus cleanliness threshold. If the bus cleanliness value MX exceeds the preset bus cleanliness threshold, it indicates that the surface contamination of the DC bus is serious and the use risk of the DC bus is relatively high, and timely inspection and processing are required, then a DC bus scan abnormal signal is generated; if the bus cleanliness value MX does not exceed the preset bus cleanliness threshold, then a DC bus scan qualified signal is generated.

[0071] Preferably, the monitoring platform is communicatively connected to the execution module, and when a DC bus scanning abnormality signal is generated, the execution module directly performs a shutdown operation to turn off the voltage output of the panel, thereby ensuring the safety of the bus, avoiding accidents, and protecting asset safety. In addition, the execution module also has the function of directly shutting down the output remotely.

[0072] Embodiment 3: Figure 3-5 As shown, the difference between this embodiment and embodiment 1 and embodiment 2 is that the present invention also proposes a connection structure of solar photovoltaic components, including: each or multiple photovoltaic components are connected to an SMP Unit {function: including but not limited to Shutdown, MPPT, communication (one or more of WIFI / BLE / PLC, etc.) and DC-DC conversion) to form a photovoltaic component group;

[0073] Several photovoltaic module groups are connected in parallel to the DC bus; they are then connected to energy devices (including but not limited to energy storage devices, hybrid inverter devices, grid-connected inverter devices, etc.) through the DC bus; it should be noted that the SMP is based on RapidShutDown, MPPT, PLC and DC-DC DC bus converter; the DC-DC specifications and PLC of all SMPs are the same; the specifications of photovoltaic modules can be the same or different.

[0074] The present invention connects a single or several photovoltaic modules in series and then connects SMPs in series to form a photovoltaic module group, which is then connected in parallel to a DC bus. Each photovoltaic module or a photovoltaic string composed of multiple photovoltaic modules is connected to an SMP, and all SMPs are then connected in parallel. This can completely solve the barrel effect of conventional string connections, while solving the power optimization of each independent photovoltaic module and string, transmitting energy and data in a DC bus manner, and has the advantages of reliable performance and strong scalability.

[0075] The working principle of the present invention: when in use, all bus connections existing on the DC bus of the solar photovoltaic module are obtained through the connection anomaly analysis module, and the abnormal connection is determined by analysis and the corresponding connection judgment symbol is assigned, so that the safety risk status of each bus connection can be reasonably evaluated. The point-by-point monitoring module performs point-by-point monitoring and analysis on the DC bus, and the corresponding bus judgment symbol is assigned by analysis, so that the operation risk status of the DC bus can be reasonably judged. The DC bus status assessment module comprehensively analyzes and accurately judges the DC bus connection status and operation risk of the solar photovoltaic module based on the connection judgment symbol and the bus judgment symbol, and reminds the management personnel to take improvement measures when the DC bus status abnormality signal is generated. It has a high degree of intelligence and is conducive to ensuring the safe and stable operation of the DC bus.

[0076] The above formulas are all dimensionless and numerical calculations. The formula is a formula obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters in the formula are set by technicians in this field according to actual conditions. The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the contents of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that technicians in the relevant technical field can understand and use the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A DC bus connection status monitoring system for solar photovoltaic modules, characterized in that: It includes monitoring platform, connection abnormality analysis module, point-to-point monitoring module, DC bus status assessment module and background terminal; The connection abnormality analysis module obtains all bus connections existing on the DC bus of the solar photovoltaic module, marks the corresponding bus connection as the target connection i, where i is a natural number greater than 1; determines the abnormal connection through analysis and assigns a connection judgment symbol LP-1 or LP-2, and sends the connection judgment symbol LP-1 or LP-2 to the DC bus state assessment module; The point-by-point monitoring module performs point-by-point monitoring and analysis on the DC bus, assigns a bus judgment symbol GP-1 or GP-2 through analysis, and sends the bus judgment symbol GP-1 or GP-2 to the DC bus state evaluation module; The DC bus state assessment module performs intersection analysis on the connection judgment symbol and the bus judgment symbol. If LP-2∩GP-2 is obtained, a DC bus state qualified signal is generated. In other cases, a DC bus state abnormal signal is generated, and the DC bus state qualified signal or the DC bus state abnormal signal is sent to the background terminal via the monitoring platform. The background terminal issues an early warning when receiving the DC bus state abnormal signal.

2. The DC bus connection status monitoring system of a solar photovoltaic module according to claim 1, characterized in that: The specific operation process of the connection analysis module includes: The connection force deviation value of the target connection i is obtained, and the real-time busbar joint contact resistance of the target connection i is collected and marked as the contact resistance measured value, and the contact resistance trend value of the target connection i is obtained through contact resistance trend analysis; The connection anomaly value is obtained by numerically calculating the connection force deviation, the measured contact resistance value and the contact resistance trend value. If the connection anomaly value exceeds the preset connection anomaly threshold, the target connection i is marked as an abnormal connection; if there is an abnormal connection, the connection judgment symbol LP-1 is assigned; if there is no abnormal connection, the connection judgment symbol LP-2 is assigned.

3. The DC bus connection status monitoring system of a solar photovoltaic module according to claim 2, characterized in that: The specific analysis process of contact resistance trend analysis is as follows: A rectangular coordinate system located in the first quadrant is established with time as the X-axis and the busbar joint contact resistance as the Y-axis, and a contact resistance curve is drawn in the rectangular coordinate system based on the contact resistance of all busbar joints at the target connection i per unit time; a number of coordinate points are marked on the contact resistance curve and defined as verification points, and the X-direction distances between two adjacent verification points are the same; And in the rectangular coordinate system, a ray parallel to the X-axis and with its endpoint on the Y-axis is drawn and marked as the resistance verification ray, and the number of verification points located above the resistance verification ray in the rectangular coordinate system is counted and marked as verification number outliers; The verification point located above the resistance verification ray is marked as an abnormal verification point, a line segment perpendicular to the resistance verification ray is made with the corresponding abnormal verification point as the endpoint and marked as a core distance line segment, the length of the core distance line segment is marked as the core distance value, and the core distance values ​​of all abnormal verification points are averaged to obtain the verification excess value, and the X-direction length and value involved in the rising part of the contact resistance curve are obtained and marked as the contact resistance increase time value; The contact resistance trend value is obtained by numerically calculating the verification value of deviation, verification value of excess and contact resistance increase time.

4. The DC bus connection status monitoring system of a solar photovoltaic module according to claim 1, characterized in that: The specific operation process of the point-by-point monitoring module includes: Several monitoring points are set on the DC bus of the solar photovoltaic module, and the real-time voltage and real-time current of all monitoring points are collected. The variance of the real-time voltage of all monitoring points is calculated to obtain the bus voltage value, and the variance of the real-time current of all monitoring points is calculated to obtain the bus current value. If the bus voltage value or the bus current value exceeds the corresponding preset threshold value, the bus judgment symbol GP-1 is assigned.

5. The DC bus connection status monitoring system of a solar photovoltaic assembly according to claim 4, characterized in that: If the bus voltage value and the bus current value do not exceed the corresponding preset threshold value, the bus point condition value of the corresponding monitoring point is obtained through analysis, and the bus abnormal value is obtained by numerically calculating the bus point measurement value, the bus abnormal point value and the bus point amplitude. If the bus abnormal value exceeds the preset bus abnormal threshold value, the bus judgment symbol GP-1 is assigned; if the bus abnormal value does not exceed the preset bus abnormal threshold value, the bus judgment symbol GP-2 is assigned.

6. The DC bus connection status monitoring system of a solar photovoltaic assembly according to claim 5, characterized in that: The specific analysis process of obtaining the busbar point condition value of the corresponding monitoring point through analysis is as follows: The deviation value of the real-time voltage of the corresponding monitoring point compared to the median of the preset suitable voltage range is marked as the bus point voltage value, the deviation value of the real-time current of the corresponding monitoring point compared to the median of the preset suitable current range is marked as the bus point current value, and the real-time temperature of the corresponding monitoring point is collected and marked as the bus point temperature value; the bus point condition value is obtained by numerically calculating the bus point voltage value, the bus point current value and the bus point temperature value.

7. The DC bus connection status monitoring system of a solar photovoltaic assembly according to claim 1, characterized in that: The monitoring platform is communicatively connected to the DC bus scanning decision module. The monitoring platform sends a DC bus status qualified signal to the DC bus scanning decision module. When the DC bus scanning decision module receives the DC bus status qualified signal, it collects the surface image of the DC bus, analyzes the surface quality condition of the DC bus based on the surface image, generates a DC bus scanning qualified signal or a DC bus scanning abnormal signal through analysis, and sends the DC bus scanning qualified signal or the DC bus scanning abnormal signal to the background terminal via the monitoring platform. When the background terminal receives the DC bus scanning abnormal signal, it issues an early warning.

8. The DC bus connection status monitoring system of a solar photovoltaic assembly according to claim 7, characterized in that: The specific analysis process of the DC bus scanning decision module is as follows: Based on the scanning image of the DC bus, whether the surface of the DC bus is damaged is judged, and if the surface of the DC bus is damaged, a DC bus scanning abnormality signal is generated; If there is no damage on the surface of the DC bus, the deviation value of the real-time distance value at the corresponding two positions on the DC bus compared to the corresponding initial distance value is collected and marked as the spacing deviation value, the average of all spacing deviation values ​​on the DC bus is marked as the spacing deviation value, and the number of spacing deviation values ​​exceeding the preset spacing deviation threshold is marked as the spacing deviation value. If the spacing deviation value or the spacing deviation value exceeds the corresponding preset threshold, a DC bus scanning abnormality signal is generated.

9. The DC bus connection status monitoring system of a solar photovoltaic assembly according to claim 8, characterized in that: If the spacing deviation table value and the spacing deviation value do not exceed the corresponding preset threshold, the scanned image of the DC bus is gray-processed, and the real-time gray-scale values ​​of all positions on the DC bus are collected. Several areas are set on the DC bus. If the non-clean surface measurement value or the gray-scale inspection value exceeds the corresponding preset threshold, the corresponding area is marked as a non-clean area; If there is a non-clean area on the DC bus, a DC bus scanning abnormal signal is generated; if there is no non-clean area on the DC bus, the bus cleanliness value is obtained by numerically calculating the non-clean surface analysis value and the grayscale analysis value. If the bus cleanliness value exceeds the preset bus cleanliness threshold, a DC bus scanning abnormal signal is generated; if the bus cleanliness value does not exceed the preset bus cleanliness threshold, a DC bus scanning qualified signal is generated.

10. The DC bus connection status monitoring system of a solar photovoltaic assembly according to claim 1, characterized in that: Each or multiple solar photovoltaic modules are connected to an SMP Unit to form a photovoltaic module group; several photovoltaic module groups are connected in parallel to the DC bus and then connected to the energy device through the DC bus.

Images