Method and system for solving problem of alternating current side short circuit impact current in optical storage system

Abstract

The invention relates to the field of power system protection, and discloses a method for solving an alternating current side short circuit impact current in an optical storage system, and the method comprises the steps: analyzing a topological structure, an impedance characteristic and a current layout of an alternating current side element, so as to monitor the real-time electrical parameters of the alternating current side element in the optical storage system; extracting short-circuit current characteristics in the historical short-circuit event from the historical operation data of the AC-side component to analyze a historical short-circuit type; identifying abnormal current in the real-time electrical parameters, and analyzing the current short circuit type of the alternating current side element; analyzing the impact risk level of the current short-circuit impact current on the alternating-current side component to construct a fault detection mechanism and a short-circuit protection device of the alternating-current side component; and processing the current short-circuit impact current in combination with a fault detection mechanism and a short-circuit protection device to obtain a current short-circuit impact current processing result. According to the invention, the fault source position can be accurately positioned, the response speed is improved, and stable operation of the optical storage system is maintained.

Description

Technical Field

[0001] The present invention relates to the field of power system protection, and in particular to a method and system for solving short-circuit impact current on the AC side in a photovoltaic storage system. Background Art

[0002] The short-circuit impact current on the AC side refers to the current that is much greater than the normal operating current and that instantly passes through the system equipment when a short-circuit fault occurs in the AC power part. By reasonably controlling the short-circuit impact current, the transmission efficiency of the power system can be improved and the energy loss caused by the short circuit can be reduced. With the rapid development of renewable energy, photovoltaic storage systems combining energy storage systems with photovoltaic power generation are becoming more and more common. In order to improve the utilization efficiency of photovoltaic storage systems, it is necessary to solve the short-circuit faults on the AC side of the photovoltaic storage system to avoid the short-circuit impact current from causing serious damage to the equipment in the system and affecting the stable operation of the system and the power supply quality.

[0003] The existing method for solving the short-circuit impact current on the AC side of the photovoltaic storage system is mainly to detect the short-circuit events of the system through traditional relays or circuit breakers, and the protection mechanism promptly cuts off the faulty part to prevent the short-circuit impact current from damaging the system. However, this method relies on manual inspections or simple threshold alarm systems, lacks rapid data analysis capabilities and response speeds, resulting in inaccurate fault source positioning and damage to equipment in the system, thereby affecting the stable operation of the photovoltaic storage system. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method and system for solving the short-circuit impact current on the AC side in a photovoltaic storage system, which can accurately locate the fault source, improve the response speed, and maintain the stable operation of the photovoltaic storage system.

[0005] In a first aspect, the present invention provides a method for solving the short-circuit impact current on the AC side in a photovoltaic storage system, comprising:

[0006] Acquire an AC side element of a photovoltaic storage system, identify a topological structure of the AC side element, analyze an impedance characteristic and a current layout of the AC side element, and monitor real-time electrical parameters of the AC side element according to the topological structure, the impedance characteristic and the current layout;

[0007] Collecting historical operation data of the AC side element, setting a normal threshold value of the historical operation data, setting a normal fluctuation range of the real-time electrical parameter under the normal threshold value, identifying historical short-circuit events of the AC side element based on the normal fluctuation range, extracting short-circuit current characteristics under the historical short-circuit events, and analyzing the historical short-circuit type of the historical short-circuit event according to the short-circuit current characteristics;

[0008] Based on the historical short-circuit type, identifying the abnormal current in the real-time electrical parameters, analyzing the potential short-circuit risk of the AC side element under the influence of the abnormal current, tracking the position interval corresponding to the abnormal current, and analyzing the current short-circuit category of the AC side element under the influence of the abnormal current based on the position interval and the short-circuit risk;

[0009] Identify the current short-circuit current corresponding to the current short-circuit category on the AC side element, analyze the phase angle when the current short-circuit current occurs, identify the periodic component of the current short-circuit current, calculate the current short-circuit impact current on the AC side element based on the periodic component and the phase angle, analyze the impact risk level of the current short-circuit impact current on the AC side element, set a fault detection mechanism for the AC side element according to the impact risk level, and set a short-circuit protection device corresponding to the fault detection mechanism;

[0010] In combination with the fault detection mechanism and the short-circuit protection device, the current short-circuit impact current is processed to obtain a current short-circuit impact current processing result.

[0011] In a possible implementation manner of the first aspect, monitoring the real-time electrical parameters of the AC side element according to the topological structure, the impedance characteristic, and the current layout includes:

[0012] Locating the component monitoring end corresponding to the AC side component according to the topological structure, the impedance characteristic and the current layout;

[0013] Configuring the monitoring device required by the component monitoring end and setting the normal monitoring standard of the monitoring device;

[0014] Setting a data processing platform corresponding to the monitoring device;

[0015] Based on the normal monitoring standard and the data processing platform, the real-time electrical parameters of the AC side components are monitored.

[0016] In a possible implementation manner of the first aspect, setting a normal fluctuation range of the real-time electrical parameter below the normal threshold includes:

[0017] Calculating the matching degree between the real-time electrical parameter and the normal threshold value;

[0018] Analyzing the conditional factors that affect the matching degree;

[0019] The deviation coefficient of the real-time electrical parameter under the condition factor is calculated using the following formula:

[0020]

[0021] Where k represents the deviation coefficient of the real-time electrical parameter, n represents the total number of measured real-time electrical parameters, i represents the index of the real-time electrical parameter, and p i represents the measured value of the ith real-time electrical parameter, Q represents the approximate value of the condition factor of the real-time electrical parameter;

[0022] According to the deviation coefficient, a normal fluctuation range of the real-time electrical parameter under the normal threshold is set.

[0023] In a possible implementation manner of the first aspect, identifying a historical short circuit event of the AC side component based on the normal fluctuation range includes:

[0024] Extracting historical electrical parameter data corresponding to the AC side components;

[0025] Analyze the change trend of the historical electrical parameter data within the normal fluctuation range;

[0026] Identifying a load surge factor of the historical electrical parameter data in the change trend;

[0027] Based on the load surge factor, historical short circuit events of the AC side component are identified.

[0028] In a possible implementation manner of the first aspect, analyzing the historical short-circuit type of the historical short-circuit event according to the short-circuit current characteristic includes:

[0029] Extracting a current waveform from the short-circuit current characteristic and analyzing a degree of distortion of the current waveform;

[0030] Identifying time series data of current and voltage in the historical short circuit event;

[0031] Based on the time series data, analyzing the change pattern of the current and voltage; analyzing the phase relationship of the current waveform under the change pattern;

[0032] The historical short-circuit type of the historical short-circuit event is analyzed according to the distortion degree and the phase relationship.

[0033] In a possible implementation manner of the first aspect, the identifying, based on the historical short circuit type, an abnormal current in the real-time electrical parameter includes:

[0034] Identifying historical electrical data corresponding to the historical short circuit type;

[0035] Matching the historical electrical data with the data consistency of the real-time electrical parameters;

[0036] Based on the data consistency, identifying abnormal data in the real-time electrical parameters;

[0037] An abnormal current in the real-time electrical parameter is extracted from the abnormal data.

[0038] In a possible implementation manner of the first aspect, analyzing the phase angle when the current short-circuit current occurs includes:

[0039] Collecting current data and voltage data when the current short-circuit current occurs;

[0040] identifying synchronization timestamps of the current data and the voltage data;

[0041] Based on the synchronization timestamp, determining a time series data set of the current data and the voltage data;

[0042] Performing frequency domain conversion on the time series data set to obtain time series frequency domain data;

[0043] Based on the time series frequency domain data, a phase angle when the current short-circuit current occurs is identified.

[0044] In a possible implementation manner of the first aspect, analyzing the impact risk level of the current short-circuit impact current on the AC side component includes:

[0045] Analyzing material properties of the AC side components;

[0046] Analyzing the maximum withstand current corresponding to the AC side component according to the material properties; analyzing the sensitivity of the AC side component to the maximum withstand current;

[0047] Setting the component sensitivity level corresponding to the sensitivity level;

[0048] The following formula is used to calculate the corresponding index weight of the AC side element in the photovoltaic storage system:

[0049]

[0050] Among them, G represents the corresponding indicator weight of the AC side component in the photovoltaic storage system, g represents the total number of AC side components in the photovoltaic storage system, f represents the index of the AC side component, j represents the evaluation indicator index in the photovoltaic storage system, and z′ fj represents the standard value of the i-th AC side component on the j-th evaluation index of the solar energy storage system, represents the average value of the jth evaluation index, p represents the total number of evaluation indicators in the solar energy storage system, and R fj represents the correlation coefficient between the fth AC side component and the fth evaluation index;

[0051] According to the indicator weight and the component sensitivity classification, the impact risk level of the current short-circuit impact current on the AC side component is analyzed.

[0052] In a possible implementation manner of the first aspect, setting a fault detection mechanism for the AC side component according to the impact risk level includes:

[0053] According to the impact risk level, setting the fault degree classification of the AC side component;

[0054] Based on the fault severity classification, setting a fault detection sequence of the AC side components;

[0055] Setting a fault warning line of the AC side element;

[0056] A fault detection mechanism for the AC side element is set based on the fault warning line and the fault detection sequence.

[0057] In a second aspect, the present invention provides a system for solving the short-circuit impact current on the AC side in a photovoltaic storage system, characterized in that the system comprises:

[0058] A data monitoring module, used to obtain the AC side elements of the photovoltaic storage system, identify the topological structure of the AC side elements, analyze the impedance characteristics and current layout of the AC side elements, and monitor the real-time electrical parameters of the AC side elements according to the topological structure, the impedance characteristics and the current layout;

[0059] A historical data analysis module, used to collect historical operation data of the AC side element, set a normal threshold value of the historical operation data, set a normal fluctuation range of the real-time electrical parameter under the normal threshold value, identify historical short-circuit events of the AC side element based on the normal fluctuation range, extract short-circuit current characteristics under the historical short-circuit events, and analyze the historical short-circuit type of the historical short-circuit event according to the short-circuit current characteristics;

[0060] a short circuit category analysis module, configured to identify the abnormal current in the real-time electrical parameters based on the historical short circuit type, analyze the potential short circuit risk of the AC side element under the influence of the abnormal current, track the position interval corresponding to the abnormal current, and analyze the current short circuit category of the AC side element under the influence of the abnormal current based on the position interval and the short circuit risk;

[0061] A short-circuit protection module, used to identify the current short-circuit current corresponding to the current short-circuit category on the AC side element, analyze the phase angle when the current short-circuit current occurs, identify the periodic component of the current short-circuit current, calculate the current short-circuit impact current on the AC side element based on the periodic component and the phase angle, analyze the impact risk level of the current short-circuit impact current on the AC side element, set a fault detection mechanism for the AC side element according to the impact risk level, and set a short-circuit protection device corresponding to the fault detection mechanism;

[0062] The short-circuit processing module is used to process the current short-circuit impact current in combination with the fault detection mechanism and the short-circuit protection device to obtain a current short-circuit impact current processing result.

[0063] Compared with the prior art, the technical principle and beneficial effects of this solution are:

[0064] The embodiment of the present invention can accurately monitor the real-time electrical parameters of the AC side of the photovoltaic storage system by acquiring the AC side elements of the photovoltaic storage system, detect abnormal conditions in the system in advance, perform preventive maintenance, reduce the occurrence of sudden failures, and thus achieve effective monitoring and optimization of system performance; further, the embodiment of the present invention can automatically identify different types of short-circuit events by extracting the short-circuit current characteristics under the historical short-circuit events, take targeted protection measures, and reduce the possibility of misoperation, and can also predict the probability of short circuits that may occur in the future to reduce the impact of failures on the system; the embodiment of the present invention can accurately locate the location of the short circuit by analyzing the current short-circuit category of the AC side element under the influence of the abnormal current based on the position interval and the short-circuit risk, quickly eliminate the fault, and optimize the relay protection device based on the analysis results of the short-circuit category, so that it can work faster and more accurately when a short-circuit event occurs; further In the embodiment of the present invention, by calculating the current short-circuit impact current on the AC side element based on the periodic component and the phase angle, the long-term impact of the short-circuit impact current on the equipment can be clarified, thereby optimizing the equipment's ability to withstand the short-circuit impact current and improving the stability of the system; the embodiment of the present invention can quickly cut off the current by setting a short-circuit protection device corresponding to the fault detection mechanism, reduce the impact of the short-circuit impact current on the system, and maintain the stable operation of the system; further, the embodiment of the present invention processes the current short-circuit impact current by combining the fault detection mechanism and the short-circuit protection device to obtain the current short-circuit impact current processing result, which can automatically detect and process short-circuit faults, reduce the time of human intervention, and improve the response speed. At the same time, it can reduce the maintenance cost of the system and equipment, reduce the additional costs caused by faults, effectively improve the safety and reliability of the system, and ensure the stable operation of the power system. Therefore, the method for solving the AC side short-circuit impact current in the photovoltaic storage system proposed in the embodiment of the present invention can accurately locate the fault source, improve the response speed, and maintain the stable operation of the photovoltaic storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0066] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0067] Figure 1 A schematic flow chart of a method for solving short-circuit impact current on the AC side in a photovoltaic storage system provided by an embodiment of the present invention;

[0068] Figure 2 A schematic diagram of a module of a system for solving short-circuit impact current on the AC side in a photovoltaic storage system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0069] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0070] The embodiment of the present invention provides a method for solving the short-circuit impact current on the AC side in a photovoltaic storage system. The execution subject of the method for solving the short-circuit impact current on the AC side in a photovoltaic storage system includes but is not limited to at least one of the electronic devices such as a server and a terminal that can be configured to execute the method provided by the embodiment of the present invention. In other words, the method for solving the short-circuit impact current on the AC side in a photovoltaic storage system can be executed by software or hardware installed in a terminal device or a server device, and the software can be a blockchain platform. The server includes but is not limited to: a single server, a server cluster, a cloud server or a cloud server cluster, etc. The server can be an independent server, or it can be a cloud server that provides cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (Content Delivery Network, CDN), and basic cloud computing services such as big data and artificial intelligence platforms.

[0071] See also Figure 1 FIG. 1 is a flow chart of a method for solving short-circuit impact current on the AC side in a photovoltaic storage system provided by an embodiment of the present invention. Figure 1 The method described in the specification for solving the short-circuit impact current on the AC side in the photovoltaic storage system includes:

[0072] S1. Acquire the AC side components of the photovoltaic storage system, identify the topological structure of the AC side components, analyze the impedance characteristics and current layout of the AC side components, and monitor the real-time electrical parameters of the AC side components according to the topological structure, the impedance characteristics and the current layout.

[0073] The embodiments of the present invention can accurately monitor the real-time electrical parameters of the AC side of the photovoltaic storage system by acquiring the AC side elements of the photovoltaic storage system, thereby realizing effective monitoring and optimization of system performance. The photovoltaic storage system refers to a comprehensive energy system integrating photovoltaic power generation and energy storage systems, and the AC side elements refer to the system part that converts the DC power generated by the photovoltaic system into AC power suitable for use in the power grid, such as inverters, circuit breakers, filters, and electric energy meters.

[0074] Optionally, the AC side components of the photovoltaic storage system can be obtained according to the usage requirements of the photovoltaic storage system, such as configuring corresponding inverters, circuit breakers, surge protectors, filters and other components according to the grid access requirements of the photovoltaic storage system.

[0075] Furthermore, the embodiment of the present invention can clarify the connection method between the components and help analyze the possible paths of the short-circuit current by identifying the topological structure of the AC side components. The topological structure refers to the connection method and layout of the components in the photovoltaic storage system.

[0076] Optionally, the topological structure identification of the AC side elements may be achieved using a design drawing of the system.

[0077] By analyzing the impedance characteristics and current layout of the AC side elements, the embodiment of the present invention can identify which nodes or paths in the system may become the main flow paths of the current in the event of a short circuit. For example, if the impedance of a path is low, then this path is likely to become the main path of the short-circuit current. The impedance characteristics refer to the degree of resistance of the AC side elements to the current, and the current layout refers to the flow path, direction and magnitude of the current in various parts of the system.

[0078] Optionally, the impedance characteristic analysis of the AC side element can be obtained by an impedance analyzer, and the current layout analysis of the AC side element can be achieved by a power analyzer.

[0079] Furthermore, the embodiments of the present invention can detect abnormal conditions in the system in advance, perform preventive maintenance, and reduce the occurrence of sudden failures by monitoring the real-time electrical parameters of the AC side elements according to the topological structure, the impedance characteristics, and the current layout. The real-time electrical parameters refer to the electrical characteristic data that dynamically changes during the operation of the system, such as current, voltage, and power.

[0080] As an embodiment of the present invention, the real-time electrical parameters of the AC side elements are monitored according to the topological structure, the impedance characteristics and the current layout, including: locating the element monitoring end corresponding to the AC side element according to the topological structure, the impedance characteristics and the current layout; configuring the monitoring device required by the element monitoring end, and setting the normal monitoring standard of the monitoring device; setting a data processing platform corresponding to the monitoring device; and monitoring the real-time electrical parameters of the AC side elements based on the normal monitoring standard and the data processing platform.

[0081] Among them, the component monitoring end refers to a monitoring point set up in the system to monitor specific electrical parameters, such as the output end of the inverter; the monitoring device refers to a device used to measure and record electrical parameters, such as a current sensor; the normal detection standard refers to the standard that the electrical parameters should meet when determining the normal operation of the system; and the data processing platform refers to a system used to collect, store, analyze and process monitoring data.

[0082] Optionally, the monitoring device configuration required for the component monitoring end can be obtained through the properties of electrical parameters, such as voltage parameters can be obtained through voltage transformers. The normal monitoring standard setting of the monitoring device can be achieved by utilizing system design and equipment specifications to set the benchmark values ​​of each electrical parameter, such as the rated output current and voltage of the inverter.

[0083] S2. Collect historical operation data of the AC side element, set a normal threshold value of the historical operation data, set a normal fluctuation range of the real-time electrical parameter under the normal threshold value, identify historical short-circuit events of the AC side element based on the normal fluctuation range, extract short-circuit current characteristics under the historical short-circuit events, and analyze the historical short-circuit type of the historical short-circuit event based on the short-circuit current characteristics.

[0084] By collecting the historical operating data of the AC side elements, the embodiment of the present invention can provide rich training samples for subsequent model training, so that the model can learn a wider range of normal operating modes, thereby having better generalization capabilities when encountering short-circuit events. The historical operating data refers to the historical electrical parameter data of the photovoltaic storage system under normal operating conditions.

[0085] Optionally, the normal operating data of the AC side components may be acquired through a data acquisition system, such as a CompactDAQ system, and the normal operating data may be standardized by data cleaning and formatting.

[0086] Furthermore, the embodiment of the present invention can identify abnormal conditions occurring in AC side components during operation by setting a normal threshold of the historical operation data, thereby understanding the short-circuit characteristics of the system. The normal threshold refers to the electrical parameter value of the system components under normal operation.

[0087] Optionally, the normal threshold setting of the historical operation data can be obtained through the equipment operation manual corresponding to the AC side component, such as the equipment instruction manual.

[0088] The embodiment of the present invention sets the normal fluctuation range of the real-time electrical parameters under the normal threshold value, so as to quickly identify the abnormal conditions of the system components, find out the fault point where the short-circuit event occurs from the abnormal conditions, and improve the response speed after the short-circuit occurs. The normal fluctuation range refers to the threshold section in which the electrical data is regarded as normal during the real-time monitoring of the normal operation of the AC side components of the photovoltaic storage system.

[0089] As an embodiment of the present invention, setting the normal fluctuation range of the real-time electrical parameter under the normal threshold includes: calculating the degree of matching between the real-time electrical parameter and the normal threshold; analyzing the conditional factors affecting the matching degree; calculating the deviation coefficient of the real-time electrical parameter under the conditional factors; and setting the normal fluctuation range of the real-time electrical parameter under the normal threshold according to the deviation coefficient.

[0090] Among them, the matching degree refers to the degree of agreement between the real-time electrical parameters and the normal threshold values, the conditional factors refer to the conditional factors that affect the matching degree, and the deviation coefficient refers to the difference coefficient between the real-time electrical parameters and the normal electrical parameters under the influence of the conditional factors.

[0091] Optionally, the calculation of the matching degree between the real-time electrical parameter and the normal threshold value can be obtained through a consistency index formula, and the conditional factor analysis of the matching degree can be achieved by diagnosing the performance of the AC side components using a diagnostic tool.

[0092] In an optional embodiment of the present invention, the deviation coefficient of the real-time electrical parameter under the condition factor is calculated using the following formula:

[0093]

[0094] Where k represents the deviation coefficient of the real-time electrical parameter, n represents the total number of measured real-time electrical parameters, i represents the index of the real-time electrical parameter, and p i represents the measured value of the ith real-time electrical parameter, and Q represents the approximate value of the condition factor of the real-time electrical parameter.

[0095] Furthermore, the embodiment of the present invention can identify the historical short-circuit events of the AC side elements based on the normal fluctuation range, thereby identifying the abnormal conditions of the system components before the short-circuit event occurs and preventing the occurrence of the short-circuit event in advance. The historical short-circuit event refers to a short-circuit accident or event of the AC side elements in the photovoltaic storage system that occurred in the past.

[0096] As an embodiment of the present invention, the identifying of historical short-circuit events of the AC side element based on the normal fluctuation range includes: extracting historical electrical parameter data corresponding to the AC side element; analyzing the change trend of the historical electrical parameter data within the normal fluctuation range; identifying the load surge factor of the historical electrical parameter data in the change trend; and identifying the historical short-circuit events of the AC side element based on the load surge factor.

[0097] Among them, the historical electrical parameter data refers to the measurement data of the AC side elements of the photovoltaic storage system during operation in the past, the change trend refers to the pattern of change of the electrical parameter data over time, and the load surge factor refers to the factor that causes the sudden increase of the electrical parameter data.

[0098] Optionally, the change trend analysis of the historical electrical parameter data within the normal fluctuation range can be obtained through software with time series analysis function, such as Tableau software, and the identification of the load surge factor of the historical electrical parameter data in the change trend can be achieved using fault tree analysis.

[0099] By extracting the short-circuit current characteristics under the historical short-circuit events, the embodiments of the present invention can determine the specific type of short circuit, thereby optimizing the setting of the relay protection device so that it can respond more quickly when a short-circuit event occurs and reduce the impact of the fault on the system. The short-circuit current characteristics refer to the characteristics and behavior patterns exhibited by the current when a short-circuit fault occurs in the system, such as a sudden increase in current.

[0100] Optionally, the short-circuit current characteristic extraction under the historical short-circuit event can be implemented by using a convolutional neural network.

[0101] Furthermore, the embodiment of the present invention can locate the fault point more quickly and accurately when a short-circuit event occurs, thereby improving the reliability of the system by analyzing the historical short-circuit types of the historical short-circuit events according to the short-circuit current characteristics. The historical short-circuit types refer to different types of short-circuit faults that occurred in the past, such as three-phase short circuit and single-phase short circuit.

[0102] As an embodiment of the present invention, analyzing the historical short-circuit type of the historical short-circuit event based on the short-circuit current characteristics includes: extracting the current waveform in the short-circuit current characteristics, and analyzing the degree of distortion of the current waveform; identifying the time series data of the current and voltage in the historical short-circuit event; based on the time series data, analyzing the change pattern of the current and voltage; analyzing the phase relationship of the current waveform under the change pattern; and analyzing the historical short-circuit type of the historical short-circuit event based on the distortion degree and the phase relationship.

[0103] Among them, the current waveform refers to the graph of current changes over time, the distortion degree refers to the degree to which the current waveform deviates from the ideal sinusoidal waveform, the current and voltage refer to the charge state and potential difference flowing through the component when a short circuit fault occurs, the time series data refers to a set of data points of current and voltage arranged in time sequence, the change pattern refers to the pattern of current and voltage changes over time, and the phase relationship refers to the time misalignment relationship between different current waveforms.

[0104] Optionally, the distortion degree analysis of the current waveform can be obtained through harmonic analysis software, such as PowerLogic PM5000 series software, the time series data identification of current and voltage in historical short-circuit events can be achieved using a multi-function electrical parameter tester, and the phase relationship analysis of the current waveform in the change mode can be obtained through the phase difference between the current waveforms.

[0105] S3. Based on the historical short-circuit type, identify the abnormal current in the real-time electrical parameters, analyze the potential short-circuit risk of the AC side element under the influence of the abnormal current, track the position interval corresponding to the abnormal current, and analyze the current short-circuit category of the AC side element under the influence of the abnormal current based on the position interval and the short-circuit risk.

[0106] The embodiment of the present invention can avoid damage to the system or equipment caused by potential faults by identifying abnormal current in the real-time electrical parameters based on the historical short-circuit type. The abnormal current refers to the abnormal current that occurs during the operation of the AC side elements of the photovoltaic storage system compared with normal working conditions.

[0107] As an embodiment of the present invention, the identifying of abnormal current in the real-time electrical parameters based on the historical short circuit type includes: identifying historical electrical data corresponding to the historical short circuit type; matching the data consistency of the historical electrical data with the real-time electrical parameters; identifying abnormal data in the real-time electrical parameters based on the data consistency; and extracting abnormal current in the real-time electrical parameters from the abnormal data.

[0108] Among them, the historical electrical data refers to the electrical parameter data corresponding to different short circuit types that occurred in the past, the data consistency refers to the consistency between the historical electrical data and the real-time electrical parameters, and the abnormal data refers to the data that is consistent or similar between the historical electrical data and the real-time electrical parameters.

[0109] Optionally, the data consistency match between the historical electrical data and the real-time electrical parameters can be obtained through a mean square error formula.

[0110] Furthermore, the embodiment of the present invention can reduce the probability of equipment damage and extend the service life of equipment by analyzing the potential short-circuit risk of the AC side elements under the influence of the abnormal current. The short-circuit risk refers to the probability of a short-circuit failure and the degree of harm of the short circuit to the system and equipment.

[0111] Optionally, the potential short-circuit risk analysis of the AC-side components under the influence of the abnormal current may be implemented using a root cause analysis method, such as a fishbone diagram analysis.

[0112] The embodiment of the present invention can quickly locate the fault by tracking the position interval corresponding to the abnormal current, thereby reducing the response time of the short-circuit fault. The position interval refers to the area where the current on the AC side component is located when the short-circuit fault occurs.

[0113] Optionally, the position interval tracking corresponding to the abnormal current can be achieved by random forest.

[0114] Furthermore, the embodiment of the present invention can accurately locate the location where the short circuit occurs and quickly eliminate the fault by analyzing the current short circuit category of the AC side element under the influence of the abnormal current based on the position interval and the short circuit risk, and optimize the relay protection device according to the analysis results of the short circuit category so that it can work faster and more accurately when a short circuit event occurs. The current short circuit category refers to different types of short circuit faults caused by the current abnormality, such as a two-phase short circuit.

[0115] Optionally, the current short-circuit category analysis of the AC-side element under the influence of the abnormal current based on the position interval and the short-circuit risk can be obtained through historical short-circuit types of historical short-circuit events.

[0116] S4. Identify the current short-circuit current corresponding to the current short-circuit category on the AC side element, analyze the phase angle when the current short-circuit current occurs, identify the periodic component of the current short-circuit current, calculate the current short-circuit impact current on the AC side element based on the periodic component and the phase angle, analyze the impact risk level of the current short-circuit impact current on the AC side element, set a fault detection mechanism for the AC side element according to the impact risk level, and set a short-circuit protection device corresponding to the fault detection mechanism.

[0117] The embodiment of the present invention can ensure that the equipment can withstand the expected maximum short-circuit current by identifying the current short-circuit current corresponding to the current short-circuit category on the AC side element, thereby avoiding damage to the equipment in a short-circuit event. The current short-circuit current refers to the current generated due to abnormal connection between conductors when a short-circuit fault occurs in the system, such as direct contact between phases or between phases and ground.

[0118] Optionally, the identification of the current short-circuit current corresponding to the current short-circuit category on the AC-side element may be achieved using an ammeter.

[0119] Furthermore, the embodiment of the present invention can more accurately locate the position of the fault and optimize the setting value of the relay protection device by analyzing the phase angle when the current short-circuit current occurs, thereby ensuring that the protection device can operate quickly and accurately when a short-circuit event occurs. The phase angle refers to the leading or lagging angle of the current waveform relative to the voltage waveform.

[0120] As an embodiment of the present invention, the analysis of the phase angle when the current short-circuit current occurs includes: collecting current data and voltage data when the current short-circuit current occurs; identifying the synchronization timestamp of the current data and the voltage data; based on the synchronization timestamp, determining the time series data set of the current data and the voltage data; performing frequency domain conversion on the time series data set to obtain time series frequency domain data; based on the time series frequency domain data, identifying the phase angle when the current short-circuit current occurs.

[0121] Among them, the current data refers to the actual measurement data of the current recorded when a short circuit fault occurs on the AC side of the photovoltaic storage system, the voltage data refers to the actual measurement data of the voltage recorded when a short circuit fault occurs on the AC side of the photovoltaic storage system, the synchronization timestamp refers to the same time point or the same time interval when the current data and the voltage data are recorded, the time series data set refers to the measurement data of the current and voltage that change with time, and the time series frequency domain data refers to the time series data after frequency domain conversion.

[0122] Optionally, the synchronous timestamp identification of the current data and the voltage data can be obtained through an NTP server in a SCADA system, and the frequency domain conversion of the time series data set can be achieved using Fourier transform.

[0123] By identifying the periodic component of the current short-circuit current, the embodiment of the present invention can understand the peak value of the short-circuit impact current, thereby selecting a device that can withstand the expected maximum short-circuit impact current and reducing the risk of damage to the device due to the short-circuit impact current. The periodic component refers to the part of the current that remains stable after a period of transition after a short circuit occurs.

[0124] Optionally, the identification of the periodic component of the current short-circuit current may be achieved by using wavelet transform, such as using wavelet packet decomposition under wavelet transform to decompose the signal into sub-band signals of different frequency bands, and separating the non-periodic component from the sub-band signal.

[0125] Furthermore, the embodiment of the present invention calculates the current short-circuit impact current on the AC side element based on the periodic component and the phase angle, so as to clarify the long-term impact of the short-circuit impact current on the equipment, thereby optimizing the equipment's ability to withstand the short-circuit impact current and improving the stability of the system. The current short-circuit impact current refers to the maximum instantaneous current value in the first cycle after the short circuit occurs.

[0126] In an optional embodiment of the present invention, the current short-circuit impact current on the AC side element is calculated using the following formula:

[0127]

[0128] Among them, I t represents the current short-circuit impulse current at time point t, t represents the time point when the current short-circuit impulse current passes, T represents the periodic component of the current short-circuit impulse current, w represents the angular frequency of the current short-circuit impulse current, θ A Represents the phase angle of the non-periodic component of the current short-circuit impulse current, θ B It represents the phase angle of the periodic component of the current short-circuit current, sin represents the waveform of the current short-circuit impulse current changing with time, and dt represents the small change in the integral variable of the current short-circuit impulse current.

[0129] The embodiment of the present invention can identify the degree of harm of the short-circuit risk to the system and equipment by analyzing the impact risk level of the current short-circuit impact current on the AC side components, and take corresponding solutions to prioritize the short-circuit risks with high degrees of harm, thereby ensuring the stable operation of the power system. The impact risk level refers to the risk classification set according to the degree of influence of the short-circuit impact current on the AC side components in the system.

[0130] As an embodiment of the present invention, the analysis of the impact risk level of the current short-circuit impact current on the AC side element includes: analyzing the material properties of the AC side element; analyzing the maximum withstand current corresponding to the AC side element based on the material properties; analyzing the sensitivity of the AC side element to the maximum withstand current; setting the component sensitivity grade corresponding to the sensitivity; calculating the indicator weight corresponding to the AC side element in the photovoltaic storage system; and analyzing the impact risk level of the current short-circuit impact current on the AC side element based on the indicator weight and the component sensitivity grade.

[0131] Among them, the material properties refer to the material properties of the AC side components, such as heat dissipation properties and insulation properties, the maximum withstand current refers to the maximum current that an electrical component can withstand, the sensitivity refers to the sensitivity of the component to currents exceeding its maximum withstand current, the component sensitivity classification refers to the grouping set according to the sensitivity of the component to overcurrent, and the indicator weight refers to the weight of the impact of the AC side components on the normal operation of the photovoltaic storage system.

[0132] Optionally, the material property analysis of the AC side element may be obtained through metallographic analysis software.

[0133] In an optional embodiment of the present invention, the indicator weight corresponding to the AC side element in the photovoltaic storage system is calculated using the following formula:

[0134]

[0135] Among them, G represents the corresponding indicator weight of the AC side component in the photovoltaic storage system, g represents the total number of AC side components in the photovoltaic storage system, f represents the index of the AC side component, j represents the evaluation indicator index in the photovoltaic storage system, and z′ fj represents the standard value of the i-th AC side component on the j-th evaluation index of the solar energy storage system, represents the average value of the jth evaluation index, p represents the total number of evaluation indicators in the solar energy storage system, and R fj It represents the correlation coefficient between the f-th AC side component and the f-th evaluation index.

[0136] Furthermore, the embodiment of the present invention sets a fault detection mechanism for the AC side components according to the impact risk level, so that potential problems of sensitive components can be identified before or in the early stages of a fault, thereby taking preventive measures in advance to avoid failures of other components, reduce maintenance costs, and reduce additional costs caused by component failures. The fault detection mechanism refers to a detection mechanism designed to identify and diagnose possible faults in the AC side components of the photovoltaic storage system.

[0137] As an embodiment of the present invention, setting the fault detection mechanism of the AC side element according to the impact risk level includes: setting the fault degree classification of the AC side element according to the impact risk level; setting the fault detection order of the AC side element based on the fault degree classification; setting the fault warning line of the AC side element; and setting the fault detection mechanism of the AC side element based on the fault warning line and the fault detection order.

[0138] Among them, the fault severity classification refers to the risk level divided according to the degree of damage that the short-circuit impact current may cause to the AC side components, the fault warning line refers to the boundary used to monitor and identify potential faults or abnormal conditions, and the fault detection sequence refers to the detection sequence set according to the importance or sensitivity of the components when a system fault occurs.

[0139] Optionally, the fault warning line setting of the AC side component can be implemented by using the technical specification of the component.

[0140] The embodiment of the present invention can quickly cut off the current, reduce the impact of the short-circuit impact current on the system, and maintain the stable operation of the system by setting a short-circuit protection device corresponding to the fault detection mechanism. The short-circuit protection device refers to a device designed in the power system to prevent short-circuit events from causing damage to equipment and systems, such as a circuit breaker.

[0141] Optionally, the short-circuit protection device setting corresponding to the fault detection mechanism can be implemented using a short-circuit protection logic algorithm, such as quickly disconnecting the circuit breaker to isolate the faulty part when a short circuit occurs.

[0142] S5. In combination with the fault detection mechanism and the short-circuit protection device, the current short-circuit impact current is processed to obtain a current short-circuit impact current processing result.

[0143] The embodiment of the present invention processes the current short-circuit impact current by combining the fault detection mechanism and the short-circuit protection device to obtain the current short-circuit impact current processing result, which can automatically detect and process short-circuit faults, reduce the time of human intervention, and improve the response speed. At the same time, it can reduce the maintenance cost of the system and equipment, reduce the additional costs caused by faults, effectively improve the safety and reliability of the system, and ensure the stable operation of the power system. The current short-circuit impact current processing result refers to the final effect after the short-circuit impact current is processed through a series of protection measures and technical means when the current short-circuit impact current occurs.

[0144] It can be seen that the embodiment of the present invention can accurately monitor the real-time electrical parameters of the AC side of the photovoltaic storage system by acquiring the AC side elements of the photovoltaic storage system, detect abnormal conditions in the system in advance, perform preventive maintenance, reduce the occurrence of sudden failures, and thus achieve effective monitoring and optimization of system performance; further, the embodiment of the present invention can automatically identify different types of short-circuit events by extracting the short-circuit current characteristics under the current short-circuit event, take targeted protection measures, and reduce the possibility of misoperation, and can also predict the probability of short circuits that may occur in the future to reduce the impact of failures on the system; the embodiment of the present invention can accurately locate the location of the short circuit by analyzing the current short-circuit category of the AC side element under the influence of the abnormal current based on the position interval and the short-circuit risk, quickly eliminate the fault, and optimize the relay protection device according to the analysis results of the current short-circuit category, so that it can work faster and more accurately when a short-circuit event occurs; Furthermore, the embodiment of the present invention calculates the current short-circuit impact current on the AC side element based on the periodic component and the phase angle, and can clarify the long-term impact of the short-circuit impact current on the equipment, thereby optimizing the equipment's ability to withstand the short-circuit impact current and improving the stability of the system; the embodiment of the present invention sets a short-circuit protection device corresponding to the fault detection mechanism, and can quickly cut off the current, reduce the impact of the short-circuit impact current on the system, and maintain the stable operation of the system; further, the embodiment of the present invention processes the current short-circuit impact current by combining the fault detection mechanism and the short-circuit protection device to obtain the short-circuit impact current processing result, which can automatically detect and process short-circuit faults, reduce the time of human intervention, and improve the response speed. At the same time, it can reduce the maintenance cost of the system and equipment, reduce the additional costs caused by faults, effectively improve the safety and reliability of the system, and ensure the stable operation of the power system. Therefore, the method for solving the AC side short-circuit impact current in the photovoltaic storage system proposed in the embodiment of the present invention can accurately locate the fault source, improve the response speed, and maintain the stable operation of the photovoltaic storage system.

[0145] like Figure 2 As shown, it is a system functional module diagram of the present invention for solving the short-circuit impact current on the AC side in the photovoltaic storage system.

[0146] The system 200 for solving the short-circuit impact current on the AC side in the photovoltaic storage system of the present invention can be installed in an electronic device. According to the functions to be implemented, the system for solving the short-circuit impact current on the AC side in the photovoltaic storage system may include a data monitoring module 201, a historical data analysis module 202, a short-circuit category analysis module 203, a short-circuit protection module 204, and a short-circuit processing module 205. The module of the present invention can also be called a unit, which refers to a series of computer program segments that can be executed by a processor of an electronic device and can complete fixed functions, which are stored in the memory of the electronic device.

[0147] In the embodiment of the present invention, the functions of each module / unit are as follows:

[0148] The data monitoring module 201 is used to obtain the AC side components of the photovoltaic storage system, identify the topological structure of the AC side components, analyze the impedance characteristics and current layout of the AC side components, and monitor the real-time electrical parameters of the AC side components according to the topological structure, the impedance characteristics and the current layout;

[0149] A historical data analysis module 202 is used to collect historical operation data of the AC side element, set a normal threshold value of the historical operation data, set a normal fluctuation range of the real-time electrical parameter under the normal threshold value, identify historical short-circuit events of the AC side element based on the normal fluctuation range, extract short-circuit current characteristics under the historical short-circuit events, and analyze the historical short-circuit type of the historical short-circuit event according to the short-circuit current characteristics;

[0150] A short circuit category analysis module 203 is used to identify the abnormal current in the real-time electrical parameters based on the historical short circuit type, analyze the potential short circuit risk of the AC side element under the influence of the abnormal current, track the position interval corresponding to the abnormal current, and analyze the current short circuit category of the AC side element under the influence of the abnormal current based on the position interval and the short circuit risk;

[0151] The short-circuit protection module 204 is used to identify the current short-circuit current corresponding to the current short-circuit category on the AC side element, analyze the phase angle when the current short-circuit current occurs, identify the periodic component of the current short-circuit current, calculate the current short-circuit impact current on the AC side element based on the periodic component and the phase angle, analyze the impact risk level of the current short-circuit impact current on the AC side element, set a fault detection mechanism for the AC side element according to the impact risk level, and set a short-circuit protection device corresponding to the fault detection mechanism;

[0152] The short-circuit processing module 205 is used to process the current short-circuit impact current in combination with the fault detection mechanism and the short-circuit protection device to obtain a current short-circuit impact current processing result.

[0153] In detail, the modules in the system 200 for solving the short-circuit impact current on the AC side in the photovoltaic storage system according to the embodiment of the present invention are used in the same manner as described above. Figure 1 The same technical means as described in the method for solving the short-circuit impact current on the AC side in the photovoltaic storage system can produce the same technical effects, so they will not be repeated here.

[0154] In addition, each functional module in each embodiment of the present invention may be integrated into one processing unit, each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of hardware plus software functional modules.

[0155] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features invented herein.

Claims

1. A method for solving short-circuit impact current on the AC side in a photovoltaic storage system, characterized in that: The method comprises: Acquire an AC side element of a photovoltaic storage system, identify a topological structure of the AC side element, analyze an impedance characteristic and a current layout of the AC side element, and monitor real-time electrical parameters of the AC side element according to the topological structure, the impedance characteristic and the current layout; Collecting historical operation data of the AC side element, setting a normal threshold value of the historical operation data, setting a normal fluctuation range of the real-time electrical parameter under the normal threshold value, identifying historical short-circuit events of the AC side element based on the normal fluctuation range, extracting short-circuit current characteristics under the historical short-circuit events, and analyzing the historical short-circuit type of the historical short-circuit event according to the short-circuit current characteristics; Based on the historical short-circuit type, identifying the abnormal current in the real-time electrical parameters, analyzing the potential short-circuit risk of the AC side element under the influence of the abnormal current, tracking the position interval corresponding to the abnormal current, and analyzing the current short-circuit category of the AC side element under the influence of the abnormal current based on the position interval and the short-circuit risk; Identify the current short-circuit current corresponding to the current short-circuit category on the AC side element, identify the phase angle when the current short-circuit current occurs, analyze the periodic component of the current short-circuit current, calculate the current short-circuit impact current on the AC side element based on the periodic component and the phase angle, analyze the impact risk level of the current short-circuit impact current on the AC side element, set a fault detection mechanism for the AC side element according to the impact risk level, and set a short-circuit protection device corresponding to the fault detection mechanism; In combination with the fault detection mechanism and the short-circuit protection device, the current short-circuit impact current is processed to obtain a current short-circuit impact current processing result.

2. The method according to claim 1, characterized in that The monitoring of the real-time electrical parameters of the AC side components according to the topological structure, the impedance characteristics and the current layout includes: Locating the component monitoring end corresponding to the AC side component according to the topological structure, the impedance characteristics and the current layout; Configuring the monitoring device required by the component monitoring end and setting the normal monitoring standard of the monitoring device; Setting a data processing platform corresponding to the monitoring device; Based on the normal monitoring standard and the data processing platform, the real-time electrical parameters of the AC side components are monitored.

3. The method according to claim 1, characterized in that The step of setting a normal fluctuation range of the real-time electrical parameter under the normal threshold value includes: Calculating the matching degree between the real-time electrical parameter and the normal threshold value; Analyzing the conditional factors that affect the matching degree; The deviation coefficient of the real-time electrical parameter under the condition factor is calculated using the following formula: Where k represents the deviation coefficient of the real-time electrical parameter, n represents the total number of measured real-time electrical parameters, i represents the index of the real-time electrical parameter, and p i represents the measured value of the ith real-time electrical parameter, Q represents the approximate value of the condition factor of the real-time electrical parameter; According to the deviation coefficient, a normal fluctuation range of the real-time electrical parameter under the normal threshold is set.

4. The method according to claim 1, characterized in that: The identifying, based on the normal fluctuation range, a historical short circuit event of the AC side component includes: Extracting historical electrical parameter data corresponding to the AC side components; Analyze the change trend of the historical electrical parameter data within the normal fluctuation range; Identifying a load surge factor of the historical electrical parameter data in the change trend; Based on the load surge factor, historical short circuit events of the AC side component are identified.

5. The method according to claim 1, characterized in that The analyzing the historical short-circuit type of the historical short-circuit event according to the short-circuit current characteristics includes: Extracting a current waveform from the short-circuit current characteristic and analyzing a degree of distortion of the current waveform; Identifying time series data of current and voltage in the historical short circuit event; Based on the time series data, analyzing the change pattern of the current and voltage; analyzing the phase relationship of the current waveform under the change pattern; The historical short-circuit type of the historical short-circuit event is analyzed according to the distortion degree and the phase relationship.

6. The method according to claim 1, characterized in that The step of identifying abnormal current in the real-time electrical parameters based on the historical short circuit type includes: Identifying historical electrical data corresponding to the historical short circuit type; Matching the historical electrical data with the data consistency of the real-time electrical parameters; Based on the data consistency, identifying abnormal data in the real-time electrical parameters; An abnormal current in the real-time electrical parameter is extracted from the abnormal data.

7. The method according to claim 1, characterized in that The analyzing the phase angle when the current short-circuit current occurs includes: Collecting current data and voltage data when the current short-circuit current occurs; identifying synchronization timestamps of the current data and the voltage data; Based on the synchronization timestamp, determining a time series data set of the current data and the voltage data; Performing frequency domain conversion on the time series data set to obtain time series frequency domain data; Based on the time series frequency domain data, a phase angle when the current short-circuit current occurs is identified.

8. The method according to claim 1, characterized in that The analyzing the impact risk level of the current short-circuit impact current on the AC side component includes: Analyzing material properties of the AC side components; Analyzing the maximum withstand current corresponding to the AC side component according to the material properties; analyzing the sensitivity of the AC side component to the maximum withstand current; Setting the component sensitivity level corresponding to the sensitivity level; The following formula is used to calculate the corresponding index weight of the AC side element in the photovoltaic storage system: Among them, G represents the corresponding indicator weight of the AC side component in the photovoltaic storage system, g represents the total number of AC side components in the photovoltaic storage system, f represents the index of the AC side component, j represents the evaluation indicator index in the photovoltaic storage system, and z ′ fj represents the standard value of the i-th AC side component on the j-th evaluation index of the solar energy storage system, represents the average value of the jth evaluation index, p represents the total number of evaluation indicators in the solar energy storage system, and R fj represents the correlation coefficient between the fth AC side component and the fth evaluation index; According to the indicator weight and the component sensitivity classification, the impact risk level of the current short-circuit impact current on the AC side component is analyzed.

9. The method according to claim 1, characterized in that: The step of setting the fault detection mechanism of the AC side component according to the impact risk level includes: According to the impact risk level, setting the fault degree classification of the AC side component; Based on the fault severity classification, setting a fault detection sequence of the AC side components; Setting a fault warning line of the AC side element; A fault detection mechanism for the AC side element is set based on the fault warning line and the fault detection sequence.

10. A system for solving short-circuit impact current on the AC side in a photovoltaic storage system, characterized in that: The system comprises: A data monitoring module, used to obtain the AC side elements of the photovoltaic storage system, identify the topological structure of the AC side elements, analyze the impedance characteristics and current layout of the AC side elements, and monitor the real-time electrical parameters of the AC side elements according to the topological structure, the impedance characteristics and the current layout; A historical data analysis module, used to collect historical operation data of the AC side element, set a normal threshold value of the historical operation data, set a normal fluctuation range of the real-time electrical parameter under the normal threshold value, identify historical short-circuit events of the AC side element based on the normal fluctuation range, extract short-circuit current characteristics under the historical short-circuit events, and analyze the historical short-circuit type of the historical short-circuit event according to the short-circuit current characteristics; a short circuit category analysis module, configured to identify the abnormal current in the real-time electrical parameters based on the historical short circuit type, analyze the potential short circuit risk of the AC side element under the influence of the abnormal current, track the position interval corresponding to the abnormal current, and analyze the current short circuit category of the AC side element under the influence of the abnormal current based on the position interval and the short circuit risk; A short-circuit protection module, used to identify the current short-circuit current corresponding to the current short-circuit category on the AC side element, analyze the phase angle when the current short-circuit current occurs, identify the periodic component of the current short-circuit current, calculate the current short-circuit impact current on the AC side element based on the periodic component and the phase angle, analyze the impact risk level of the current short-circuit impact current on the AC side element, set a fault detection mechanism for the AC side element according to the impact risk level, and set a short-circuit protection device corresponding to the fault detection mechanism; The short-circuit processing module is used to process the current short-circuit impact current in combination with the fault detection mechanism and the short-circuit protection device to obtain a current short-circuit impact current processing result.

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