CN216216776U - Photovoltaic system, fault detection circuit thereof and photovoltaic equipment - Google Patents
Photovoltaic system, fault detection circuit thereof and photovoltaic equipment Download PDFInfo
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Abstract
The utility model relates to a photovoltaic system and fault detection circuit, photovoltaic equipment thereof divides the photovoltaic system into subassembly level, group cascade and load level, at the photovoltaic system operation in-process, gathers the subassembly level electrical parameter that the subassembly level corresponds, the group cascade electrical parameter that the group cascade corresponds and the load level electrical parameter that the load level corresponds respectively, later carries out analysis each electrical parameter and preset parameter threshold value, to the signal processing circuit output subassembly level signal, group cascade level signal and load level signal of photovoltaic system. Finally, whether the photovoltaic system fails or not and the specific position of the photovoltaic system are obtained by combining a first fault detection signal output by the signal processing circuit under the component level signal, a second fault detection signal output under the group string level signal and a third fault detection signal output under the load level signal, so that the working reliability of the photovoltaic system is effectively improved.
Description
Technical Field
The application relates to the technical field of photovoltaics, in particular to a photovoltaic system and a fault detection circuit and photovoltaic equipment thereof.
Background
With the development of the photovoltaic industry, photovoltaic inverters and photovoltaic air conditioners are greatly popularized. The photovoltaic inverter can be used for converting variable direct-current voltage generated by the photovoltaic solar panel into alternating current with commercial power frequency, and the alternating current is fed back to a commercial power transmission system or is supplied to an off-grid power grid.
With the improvement of the efficiency and the capacity of the photovoltaic inverter, the number of accessible groups of a photovoltaic system is continuously increased, and is increased from one to two strings to four to eight strings. When any one photovoltaic module in a string of the photovoltaic system fails, the normal operation of the whole photovoltaic system is affected; for a photovoltaic system with a parallel operation condition, a photovoltaic module breaks down, and the photovoltaic system is easily subjected to great loss. Therefore, the conventional photovoltaic system has poor operational reliability.
SUMMERY OF THE UTILITY MODEL
Therefore, it is necessary to provide a photovoltaic system, a fault detection circuit thereof and a photovoltaic device, aiming at the problem of poor working reliability of the conventional photovoltaic system.
A fault detection circuit for a photovoltaic system, comprising: the photovoltaic module comprises a module level parameter acquisition device, a photovoltaic module control device and a control device, wherein the module level parameter acquisition device is connected to the output end of a photovoltaic module of a photovoltaic system and is used for acquiring module level electrical parameters of the photovoltaic module; the group cascade parameter acquisition device is connected to the output end of a photovoltaic string of the photovoltaic system and is used for acquiring group cascade electrical parameters of the photovoltaic string; the load level parameter acquisition device is connected to the output end of a load of the photovoltaic system and is used for acquiring load level electrical parameters of the load; a signal processing circuit; the processing device is connected with the input end of the signal processing circuit, and the output end of the signal processing circuit is connected with the processing device; the processing device is used for outputting a component level signal, a group cascade level signal and a load level signal to the signal processing circuit according to the component level electrical parameter, the group cascade electrical parameter, the load level electrical parameter and a preset parameter threshold; and fault positioning is carried out on the photovoltaic system according to a first fault detection signal output by the signal processing circuit under the component level signal, a second fault detection signal output by the group of cascade level signals and a third fault detection signal output by the load level signal.
In one embodiment, the signal processing circuit includes a component-level signal processing circuit, a group serial-level signal processing circuit, and a load-level signal processing circuit, the component-level parameter collecting device is connected to an input terminal of the component-level signal processing circuit through the processing device, the group serial-level parameter collecting device is connected to an input terminal of the group serial-level signal processing circuit through the processing device, the load-level parameter collecting device is connected to an input terminal of the load-level signal processing circuit through the processing device, and an output terminal of the component-level signal processing circuit, an output terminal of the group serial-level signal processing circuit, and an input terminal of the load-level signal processing circuit are all connected to the processing device.
In one embodiment, the output terminal of the component-level signal processing circuit, the output terminal of the group of serial-level signal processing circuits, and the output terminal of the load-level signal processing circuit are connected to the processing device by multiplexing the same signal line;
and/or the component level parameter acquisition device, the group of serial level parameter acquisition devices and the load level parameter acquisition device are connected with the processing device by multiplexing the same signal line.
In one embodiment, the module-level signal processing circuit includes a first comparator, a first switch device and a first optical coupler device, a first input end of the first comparator serves as an input end of the module-level signal processing circuit, a second input end of the first comparator is connected with a power supply, an output end of the first comparator is connected with a control end of the first switch device, a first end of the first switch device is connected with the power supply, a second end of the first switch device is connected with a first end of a light emitter of the first optical coupler device, a second end of the light emitter of the first optical coupler device is grounded, a first end of a light receiver of the first optical coupler device is connected with the first power supply, and a second end of the light receiver of the first optical coupler serves as an output end of the module-level signal processing circuit.
In one embodiment, the group cascade signal processing circuit includes a second comparator, a second switch device and a second optical coupler device, a first input end of the second comparator serves as an input end of the group cascade signal processing circuit, a second input end of the second comparator is connected to a power supply, an output end of the second comparator is connected to a control end of the second switch device, a first end of the second switch device is connected to the power supply, a second end of the second switch device is connected to a first end of a light emitter of the second optical coupler device, a second end of the light emitter of the second optical coupler device is grounded, a first end of a light receiver of the second optical coupler device is connected to the second power supply, and a second end of the light receiver of the second optical coupler serves as an output end of the group cascade signal processing circuit.
In one embodiment, the load-level signal processing circuit includes a third comparator, a third switching device and a third optical coupling device, a first input end of the third comparator is used as an input end of the load-level signal processing circuit, a second input end of the third comparator is connected with a power supply, an output end of the third comparator is connected with a control end of the third switching device, a first end of the third switching device is connected with the power supply, a second end of the third switching device is connected with a first end of a light emitter of the third optical coupling device, a second end of the light emitter of the third optical coupling device is grounded, a first end of a light receiver of the third optical coupling device is connected with the third power supply, and a second end of the light receiver of the third optical coupling device is used as an output end of the load-level signal processing circuit; the voltage values of the first power supply, the second power supply, and the third power supply are different from each other.
In one embodiment, the voltage value of the third power supply is greater than the voltage value of the second power supply, which is greater than the voltage value of the first power supply.
In one embodiment, the component level parameter acquisition device, the group string level parameter acquisition device, and the load level parameter acquisition device are all leakage current sensors.
A photovoltaic system comprises the fault detection circuit.
A photovoltaic device comprises the photovoltaic system.
According to the photovoltaic system, the fault detection circuit and the photovoltaic equipment, the photovoltaic system is divided into a component level, a group string level and a load level, in the operation process of the photovoltaic system, component level electrical parameters corresponding to the component level, group string level electrical parameters corresponding to the group string level and load level electrical parameters corresponding to the load level are respectively collected, then the component level electrical parameters, the group string level electrical parameters, the load level electrical parameters and preset parameter thresholds are analyzed, and component level signals, group string level signals and load level signals are output to a signal processing circuit of the photovoltaic system. And finally, combining a first fault detection signal output by the signal processing circuit under the component level signal, a second fault detection signal output under the group string level signal and a third fault detection signal output under the load level signal to obtain whether the photovoltaic system has a fault and the specific position of the fault. Through the scheme, the fault detection of the photovoltaic system can be realized, the fault location can be carried out when the fault occurs, operation and maintenance personnel can conveniently and timely overhaul, and the working reliability of the photovoltaic system is effectively improved.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram of a fault detection circuit of a photovoltaic system according to an embodiment;
FIG. 2 is a schematic diagram of fault detection for a photovoltaic system in one embodiment;
FIG. 3 is a schematic diagram of a signal processing circuit according to an embodiment;
FIG. 4 is a flow chart illustrating a filtering process according to an embodiment.
Detailed Description
To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are illustrated in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Referring to fig. 1, a fault detection circuit of a photovoltaic system includes: the module-level parameter acquisition device 10 is connected to the output end of a photovoltaic module of the photovoltaic system and is used for acquiring module-level electrical parameters of the photovoltaic module; the group cascade parameter acquisition device 20 is connected to the output end of the photovoltaic string of the photovoltaic system and is used for acquiring group cascade electrical parameters of the photovoltaic string; the load level parameter acquisition device 30 is connected to the output end of the load of the photovoltaic system and is used for acquiring the load level electrical parameters of the load; a signal processing circuit 40; the processing device 50 is connected with the component-level parameter acquisition device 10, the group serial-level parameter acquisition device 20 and the load-level parameter acquisition device 30, the processing device 50 is connected with the input end of the signal processing circuit 40, and the output end of the signal processing circuit 40 is connected with the processing device 50; the processing device 50 is configured to output a component level signal, a group string level signal, and a load level signal to the signal processing circuit 40 according to the component level electrical parameter, the group string level electrical parameter, the load level electrical parameter, and a preset parameter threshold; and fault location is performed on the photovoltaic system according to a first fault detection signal output by the signal processing circuit 40 under the component level signal, a second fault detection signal output under the group string level signal and a third fault detection signal output under the load level signal.
Specifically, referring to fig. 2, a photovoltaic system includes a load and a plurality of photovoltaic strings, each of the photovoltaic strings is connected to the load to supply power to the load, and each of the photovoltaic strings includes a plurality of photovoltaic modules connected to each other to form a photovoltaic string. According to different actual failure positions, the failure level of the photovoltaic system can be divided into a component level, a group cascade level and a load level, wherein the component level is that the photovoltaic component of the photovoltaic system fails, the group cascade level is that the photovoltaic group string of the photovoltaic system fails, and the load level is that the load of the photovoltaic system fails. Therefore, in the actual detection process, corresponding electrical parameters need to be acquired for detection and analysis according to different fault levels. The module-level electrical parameter is an electrical parameter at a photovoltaic module of the photovoltaic system, the string-level electrical parameter is an electrical parameter at a photovoltaic string of the photovoltaic system, and the load-level electrical parameter is an electrical parameter at a load of the photovoltaic system.
The photovoltaic system is characterized in that a component-level parameter acquisition device 10 is arranged at a photovoltaic component, a group string-level parameter acquisition device 20 is arranged at a photovoltaic string, a load-level parameter acquisition device 30 is arranged at a load, and component-level electrical parameters, group string-level electrical parameters and load-level electrical parameters of the photovoltaic system are acquired in real time through the parameter acquisition devices and are sent to a processing device 50.
It is understood that the specific types of the component-level electrical parameters, the group string-level electrical parameters, and the load-level electrical parameters are not unique, and the corresponding component-level electrical parameters, group string-level electrical parameters, and load-level electrical parameters may be different according to the actual type of the detected fault. For example, in one embodiment, the leakage current fault detection is implemented by the fault detection method, and the corresponding component-level electrical parameter, the group string-level electrical parameter, and the load-level electrical parameter are the leakage current parameter at the photovoltaic component, the leakage current parameter at the photovoltaic group string, and the leakage current parameter at the load, respectively. In other embodiments, detection of an insulation resistance fault, a ground fault, or a short-circuit fault may also be implemented, and at this time, fault analysis needs to be implemented by detecting a resistance to ground, and the corresponding electrical parameters are a drain voltage parameter at the photovoltaic module, a voltage parameter at the photovoltaic string, and a voltage parameter at the load.
The processing device 50 pre-stores a preset parameter threshold, and after obtaining the component-level electrical parameter, the group string-level electrical parameter, and the load-level electrical parameter, the processing device 50 performs comparison analysis by combining the component-level electrical parameter, the group string-level electrical parameter, the load-level electrical parameter, and the preset parameter threshold, and finally outputs a component-level signal, a group string-level signal, and a load-level signal to the signal processing circuit 40 of the photovoltaic system, so that the signal processing circuit 40 performs fault analysis.
It should be noted that the specific type of the preset parameter threshold is not unique, and the preset parameter may be different according to the type of the fault detection to be implemented. In order to facilitate understanding of the technical solution of the present application, a specific fault detection type is explained as an example of leakage current detection. Correspondingly, in an embodiment, the preset parameter threshold may be a single current threshold, for example, 300mA, and in the scheme of this embodiment, the component-level electrical parameter, the group-string-level electrical parameter, and the load-level electrical parameter are leakage current values actually acquired by each parameter acquisition device, and at this time, only the actually acquired leakage current needs to be compared and analyzed with the preset parameter threshold.
In another embodiment, the preset parameter threshold may also be a sudden change threshold of the leakage current, and at this time, the preset parameter threshold may be set to 30mA, 60mA, 150mA, or the like, and the corresponding component-level electrical parameter, the group-string-level electrical parameter, and the load-level electrical parameter acquired by the processing device 50 at this time should be a change value of each electrical parameter from the last acquired value. In the solution of this embodiment, after the actually collected leakage current value is different from the leakage current collected last time, the leakage current variation value is compared and analyzed with the preset parameter threshold.
After the processing device 50 outputs the component level signal, the group string level signal and the load level signal to the signal processing circuit 40, the signal processing circuit 40 outputs a first failure detection signal to the processing device 50 by the component level signal, and the failure state of the component level is reflected by the first failure detection signal. Under the action of the group cascade level signal, the signal processing circuit 40 outputs a second fault detection signal to the processing device 50, and the fault state of the group cascade can be reflected through the second fault detection signal. Under the action of the load level signal, the signal processing circuit 40 outputs a third fault detection signal to the processing device 50, and the fault state of the load level can be reflected by the third fault detection signal. Finally, the processing device 50 obtains whether the current photovoltaic system fails and the specific location of the current photovoltaic system by combining the specific condition analysis of the first fault detection signal, the second fault detection signal and the third fault detection signal, so as to realize fault location.
When analyzing according to the acquired electrical parameters, the processing device 50 specifically compares and analyzes the component-level electrical parameters, the group serial-level electrical parameters, and the load-level electrical parameters with preset parameter thresholds, and outputs a component-level signal to the signal processing circuit 40 according to the comparison and analysis results of the component-level electrical parameters and the preset parameter thresholds; combining the comparison and analysis result of the group cascade electrical parameter and the preset parameter threshold value, and outputting a group cascade level signal to the signal processing circuit 40; and outputting a load level signal to the signal processing circuit 40 according to the comparison and analysis result of the load level electrical parameter and the preset parameter threshold. The signal processing circuit 40 has three signal input ports, three level signals act on the signal processing circuit 40 at the same time, and finally the signal processing circuit 40 outputs different fault detection signal combinations to the processing device 50 according to the difference of each level signal so as to realize fault positioning.
Referring to fig. 3, in an embodiment, the signal processing circuit 40 includes a component-level signal processing circuit 41, a group serial-level signal processing circuit 42, and a load-level signal processing circuit 43, the component-level parameter collecting device 10 connects an input terminal (not shown) of the component-level signal processing circuit 41 through the processing device 50, the group serial-level parameter collecting device 20 connects an input terminal (not shown) of the group serial-level signal processing circuit 42 through the processing device 50, the load-level parameter collecting device 30 connects an input terminal (not shown) of the load-level signal processing circuit 43 through the processing device 50, and an output terminal of the component-level signal processing circuit 41, an output terminal of the group serial-level signal processing circuit 42, and an input terminal of the load-level signal processing circuit 43 are all connected to the processing device 50.
Specifically, the component-level signal processing circuit 41 is configured to output a corresponding component-level fault detection result (i.e., a first fault detection signal) to the processing device 50 according to the received component-level signal, the group-string-level signal processing circuit 42 is configured to output a corresponding group-string-level fault detection result (i.e., a second fault detection signal) to the processing device 50 according to the received group-string-level signal, and the load-level signal processing circuit 43 is configured to output a corresponding load-level fault detection result (i.e., a third fault detection signal) to the processing device 50 according to the received load-level signal.
More specifically, in one embodiment, the processing device 50 outputs a first component level signal to the component-level signal processing circuit 40 when the component-level electrical parameter is greater than or equal to a preset parameter threshold; outputting a second component level signal to the component-level signal processing circuit 40 when the component-level electrical parameter is less than the preset parameter threshold;
and/or, when the string-level electrical parameter is greater than or equal to the preset parameter threshold, the processing device 50 outputs a first string-level signal to the string-level signal processing circuit 40; when the string level electrical parameter is less than the preset parameter threshold, outputting a second string level signal to the string level signal processing circuit 40;
and/or, when the load level electrical parameter is greater than or equal to the preset parameter threshold, the processing device 50 outputs a first load level signal to the load level signal processing circuit 40; when the load stage electrical parameter is less than the preset parameter threshold, a second load level signal is output to the load stage signal processing circuit 40.
In this embodiment, when comparing and analyzing the component-level electrical parameter, the group-string-level electrical parameter, and the load-level electrical parameter with the preset parameter threshold, different types of level signals are correspondingly output according to different magnitude relationships between the three and the preset parameter threshold, so that each signal processing circuit 40 enters different working states, and different results can be output to the processing device 50.
Further, in one embodiment, each signal processing circuit 40 multiplexes one signal output line to be connected to the processing device 50, and accordingly, the first fault detection signal, the second fault detection signal, and the third fault detection signal have different priorities. The priority of the third fault detection signal is the highest priority of the fault type signal, the priority of the second fault detection signal is lower than the priority of the third fault detection signal, and the priority of the first fault detection signal is lower than the priority of the second fault detection signal.
When the third fault detection signal indicates that a fault exists, the signal will cover the second fault detection signal and the first fault detection signal, and the processing device 50 determines according to the received third fault detection signal, and finally locates the fault position to obtain a load level, so as to obtain a detection result that the load level has a fault. And when the second fault detection signal indicates that a fault exists and the third fault detection signal indicates that no fault exists, the processing device 50 will locate the fault position to obtain a string level, and obtain a detection result that the string level has a fault. When only the third fault detection signal indicates that a fault exists, and the rest of the signals indicate that no fault exists, the processing device 50 will locate the fault position to obtain the component level, and obtain the detection result of the component level that a fault occurs.
In one embodiment, the processing device 50 performs filtering processing on the component-level electrical parameter, the group string-level electrical parameter, and the load-level electrical parameter, respectively, to obtain a filtered component-level electrical parameter, a filtered group string-level electrical parameter, and a filtered load-level electrical parameter. And respectively outputting a component level signal, a group string level signal and a load level signal to a signal processing circuit 40 of the photovoltaic system according to the filtered component level electrical parameter, the filtered group string level electrical parameter, the filtered load level electrical parameter and a preset parameter threshold value.
Specifically, in the scheme of this embodiment, before the obtained component-level electrical parameters, group-serial electrical parameters, and load-level electrical parameters are analyzed in combination with the preset parameter threshold, the component-level electrical parameters, group-serial electrical parameters, and load-level electrical parameters are further filtered, and the problem of inaccurate detection is effectively avoided by filtering out accidental pulse interference from the collected electrical parameters.
For ease of understanding, the following explanation will be made with the electrical parameter as the leakage current parameter and the fault detection implemented as the leakage current detection. Referring to fig. 4, in the scheme of this example, filtering and hysteresis processing are performed on the acquired device-level electrical parameters, the group-string-level electrical parameters, and the load-level electrical parameters by using a necessary filtering algorithm, so as to avoid error protection and error actions caused by voltage value fluctuation. The filtering is implemented by acquiring leakage current data of N (different settings may be specifically performed in combination with actual requirements) cycles by the processing device 50 to form an array T, removing the maximum value and the minimum value in the array T by logical comparison, and performing an averaging operation on the remaining data. The filtering mode is suitable for systems which are easy to have abnormal values, and can effectively filter accidental pulse interference. The problem of inaccurate detection can be effectively avoided by processing the actual leakage current.
In one embodiment, with continued reference to fig. 3, the module-level signal processing circuit 41 includes a first comparator U1, a first switching device Q1 and a first optical coupler Q4, a first input terminal of the first comparator U1 serves as an input terminal of the module-level signal processing circuit 41, a second input terminal of the first comparator U1 is connected to the power supply, an output terminal of the first comparator U1 is connected to a control terminal of the first switching device Q1, a first terminal of the first switching device Q1 is connected to the power supply, a second terminal of the first switching device Q1 is connected to the first terminal of the light emitter of the first optical coupler Q4, a second terminal of the light emitter of the first optical coupler Q4 is grounded, a first terminal of the light receiver of the first optical coupler Q4 is connected to the first power supply S1, and a second terminal of the light receiver of the first optical coupler Q4 serves as an output terminal of the module-level signal processing circuit 41.
And/or the group serial signal processing circuit 42 comprises a second comparator U2, a second switching device Q2 and a second optical coupler Q5, a first input end of the second comparator U2 serves as an input end of the group serial signal processing circuit 42, a second input end of the second comparator U2 is connected with a power supply, an output end of the second comparator U2 is connected with a control end of the second switching device Q2, a first end of the second switching device Q2 is connected with the power supply, a second end of the second switching device Q2 is connected with a first end of a light emitter of the second optical coupler Q5, a second end of the light emitter of the second optical coupler Q5 is grounded, a first end of a light receiver of the second optical coupler Q5 is connected with the second power supply S2, and a second end of the light receiver of the second optical coupler Q5 serves as an output end of the group serial signal processing circuit 42.
And/or the load-level signal processing circuit 43 comprises a third comparator U3, a third switching device Q3 and a third optical coupler Q6, a first input end of the third comparator U3 serves as an input end of the load-level signal processing circuit 43, a second input end of the third comparator U3 is connected with a power supply, an output end of the third comparator U3 is connected with a control end of the third switching device Q3, a first end of the third switching device Q3 is connected with the power supply, a second end of the third switching device Q3 is connected with a first end of a light emitter of the third optical coupler Q6, a second end of the light emitter of the third optical coupler Q6 is grounded, a first end of a light receiver of the third optical coupler Q6 is connected with the third power supply S3, and a second end of the light receiver of the third optical coupler Q6 serves as an output end of the load-level signal processing circuit 43; the voltage values of the first power source S1, the second power source S2, and the third power source S3 are different from each other.
Accordingly, in a more detailed embodiment, the first component level signal is a high level signal, the second component level signal is a low level signal, the first string level signal is a high level signal, the second string level signal is a low level signal, the first load level signal is a high level signal, and the first load level signal is a low level signal. Taking a component level as an example, when the component level parameter acquiring device 10 acquires a component level electrical parameter and sends the component level electrical parameter to the processing device 50, and when the processing device 50 analyzes that the component level electrical parameter is greater than or equal to a preset parameter threshold, the output of the processing device 50 is set to a high level from a low level (i.e., a first component level signal is output), the high level is sent to the first comparator U1 for signal judgment, the first comparator U1 outputs a high level after the operational amplifier judgment, the high level signal enables the first switching device Q1 to be conducted, the first switching device Q1 is conducted to enable the first optical coupler Q4 to be conducted, finally, a voltage signal (i.e., a first fault detection signal) of the external first power source S1 is output to the processing device 50, and the processing device 50 receives the voltage signal for fault judgment and judges that a component level fault occurs. The operation of the group cascade stage and the load stage is the same as that of the component stage, and will not be described herein.
It can be understood that the output terminal of the component-level signal processing circuit 41, the output terminal of the group-serial-level signal processing circuit 42, and the output terminal of the load-level signal processing circuit 43 may be respectively connected to the processing device 50 by using one signal line, or may be connected to the processing device 50 by multiplexing the same signal line, and may specifically perform different selections according to actual requirements. Accordingly, in order to easily distinguish between the failures of the component stage, the group string stage, and the load stage, the voltage values of the first power supply S1, the second power supply S2, and the third power supply S3 are set to be different from each other.
Further, in one embodiment, the voltage value of the third power source S3 is greater than the voltage value of the second power source S2, and the voltage value of the second power source S2 is greater than the voltage value of the first power source S1.
Specifically, in the scheme of this embodiment, the voltage value of the third power supply S3 is greater than the voltage value of the second power supply S2, and the voltage value of the second power supply S2 is greater than the voltage value of the first power supply S1, so that the load-level fault detection priority is higher than the group-level serial fault detection priority, which is higher than the component-level fault detection priority. For example, in a more detailed embodiment, the voltage value of the third power supply S3 may be set to 5V, the voltage value of the second power supply S2 may be set to 3V, and the voltage value of the first power supply S1 may be set to 1V.
When the third fault detection signal indicates that there is a fault, that is, the load level signal processing circuit 43 outputs a voltage value corresponding to the magnitude of the third power source S3, the voltage value will cover the second fault detection signal and the first fault detection signal, the processing device 50 determines according to the received third fault detection signal, and finally locates the fault position to obtain a load level, so as to obtain a detection result of the fault occurring in the load level. The second fault detection signal represents that a fault exists, and the third fault detection signal indicates that no fault occurs, that is, the processing device 50 receives the voltage value corresponding to the second power source S2 and does not receive the voltage value corresponding to the third power source S3, the voltage value will cover the voltage value corresponding to the first power source S1, and the processing device 50 will locate the fault position to obtain a group cascade, so as to obtain a detection result that the group cascade has a fault. Only the third fault detection signal indicates that a fault exists, and the rest of the third fault detection signals indicate that no fault exists, that is, the processing device 50 only receives the voltage value corresponding to the first power supply S1, the processing device 50 will locate the fault position to obtain a component level, and obtain a detection result that the component level has a fault.
It should be noted that in one embodiment, the output of the component-level signal processing circuit 41, the output of the group-string-level signal processing circuit 42, and the output of the load-level signal processing circuit 43 are connected to the processing device 50 by multiplexing the same signal line;
and/or the component-level parameter acquisition device 10, the group-level serial parameter acquisition device 20 and the load-level parameter acquisition device 30 multiplex the same signal line connection processing device 50.
Specifically, because the number of photovoltaic modules and photovoltaic string accesses of the photovoltaic system is large nowadays, the processing resource of the processing device 50 is limited, all levels of fault output signals are collected into one path and output to the processing device 50 (specifically, an MCU and the like), for different fault levels, the judgment is performed through different voltage levels, the highest level fault can be set to be the highest voltage level, the voltage level of the next level fault is sequentially decreased, the highest level fault directly covers the lower level fault voltage signal, so that the equipment performs timely, rapid and thorough fault protection processing, damage to all levels of system equipment is prevented, the processing device 50 uses the detected different voltage levels as the judgment threshold values of different levels of faults, and multifunctional fault judgment multiplexing can be realized.
Therefore, the processing device 50 is connected with each parameter acquisition device by multiplexing signal lines, or the output end of each signal processing circuit 40 is connected to the processing device 50 by one multiplexing signal line, so that the control interface resources can be effectively saved, and the external signal detection and judgment of a complex photovoltaic system can be conveniently realized, so as to adapt to the application scene of a large photovoltaic equipment system.
It is to be understood that the specific types of the component-level parameter collecting means 10, the group-string-level parameter collecting means 20 and the load-level parameter collecting means 30 are not exclusive, and may be different according to the fault detection type. For example, in one embodiment, the component-level parameter collection device 10, the group-level parameter collection device 20, and the load-level parameter collection device 30 are all leakage current sensors, and thus leakage current type fault detection can be achieved. In other embodiments, the component-level parameter collecting device 10, the group-level serial-level parameter collecting device 20, and the load-level parameter collecting device 30 may also be voltage detectors, in which case the detection of an insulation resistance fault, a ground fault, or a short-circuit fault may be implemented.
According to the fault detection circuit of the photovoltaic system, the photovoltaic system is divided into a component level, a group string level and a load level, in the operation process of the photovoltaic system, component level electrical parameters corresponding to the component level, group string level electrical parameters corresponding to the group string level and load level electrical parameters corresponding to the load level are respectively collected, then the component level electrical parameters, the group string level electrical parameters, the load level electrical parameters and preset parameter thresholds are analyzed, and component level signals, group string level signals and load level signals are output to a signal processing circuit of the photovoltaic system. And finally, combining a first fault detection signal output by the signal processing circuit under the component level signal, a second fault detection signal output under the group string level signal and a third fault detection signal output under the load level signal to obtain whether the photovoltaic system has a fault and the specific position of the fault. Through the scheme, the fault detection of the photovoltaic system can be realized, the fault location can be carried out when the fault occurs, operation and maintenance personnel can conveniently and timely overhaul, and the working reliability of the photovoltaic system is effectively improved.
A photovoltaic system comprises the fault detection circuit.
Specifically, as shown in the above embodiments and the drawings, in the actual fault detection, the processing device 50 first obtains the component-level electrical parameter, the group-string-level electrical parameter, and the load-level electrical parameter. The module-level electrical parameters, the group string-level electrical parameters and the load-level electrical parameters of the photovoltaic system are acquired in real time through the parameter acquisition devices and are sent to the processing device 50, namely, the representation processing device 50 acquires the module-level electrical parameters, the group string-level electrical parameters and the load-level electrical parameters.
The processing device 50 pre-stores a preset parameter threshold, and after obtaining the component-level electrical parameter, the group string-level electrical parameter, and the load-level electrical parameter, the processing device 50 performs comparison analysis by combining the component-level electrical parameter, the group string-level electrical parameter, the load-level electrical parameter, and the preset parameter threshold, and finally outputs a component-level signal, a group string-level signal, and a load-level signal to the signal processing circuit 40 of the photovoltaic system, so that the signal processing circuit 40 performs fault analysis.
After the processing device 50 outputs the component level signal, the group string level signal and the load level signal to the signal processing circuit 40, the signal processing circuit 40 outputs a first failure detection signal to the processing device 50 by the component level signal, and the failure state of the component level is reflected by the first failure detection signal. Under the action of the group cascade level signal, the signal processing circuit 40 outputs a second fault detection signal to the processing device 50, and the fault state of the group cascade can be reflected through the second fault detection signal. Under the action of the load level signal, the signal processing circuit 40 outputs a third fault detection signal to the processing device 50, and the fault state of the load level can be reflected by the third fault detection signal. Finally, the processing device 50 obtains whether the current photovoltaic system fails and the specific location of the current photovoltaic system by combining the specific condition analysis of the first fault detection signal, the second fault detection signal and the third fault detection signal, so as to realize fault location.
The photovoltaic system is divided into a component level, a group string level and a load level, in the operation process of the photovoltaic system, component level electrical parameters corresponding to the component level, group string level electrical parameters corresponding to the group string level and load level electrical parameters corresponding to the load level are respectively collected, then the component level electrical parameters, the group string level electrical parameters, the load level electrical parameters and preset parameter thresholds are analyzed, and component level signals, group string level signals and load level signals are output to a signal processing circuit 40 of the photovoltaic system. Finally, the first fault detection signal output by the signal processing circuit 40 under the component level signal, the second fault detection signal output under the group string level signal, and the third fault detection signal output under the load level signal are combined to obtain whether the photovoltaic system is in fault or not and the specific position of the fault. Through the scheme, the fault detection of the photovoltaic system can be realized, the fault location can be carried out when the fault occurs, operation and maintenance personnel can conveniently and timely overhaul, and the working reliability of the photovoltaic system is effectively improved.
A photovoltaic device comprises the photovoltaic system.
Specifically, as shown in the above embodiments and the accompanying drawings, the photovoltaic system and the fault detection circuit are not unique in the specific type of the photovoltaic device, and may be a photovoltaic air conditioner or the like, and the corresponding load is an electrical device such as a compressor in the photovoltaic air conditioner. In actual fault detection, the processing device 50 first performs acquisition of the component-level electrical parameters, the group-string-level electrical parameters, and the load-level electrical parameters. The module-level electrical parameters, the group string-level electrical parameters and the load-level electrical parameters of the photovoltaic system are acquired in real time through the parameter acquisition devices and are sent to the processing device 50, namely, the representation processing device 50 acquires the module-level electrical parameters, the group string-level electrical parameters and the load-level electrical parameters.
The processing device 50 pre-stores a preset parameter threshold, and after obtaining the component-level electrical parameter, the group string-level electrical parameter, and the load-level electrical parameter, the processing device 50 performs comparison analysis by combining the component-level electrical parameter, the group string-level electrical parameter, the load-level electrical parameter, and the preset parameter threshold, and finally outputs a component-level signal, a group string-level signal, and a load-level signal to the signal processing circuit 40 of the photovoltaic system, so that the signal processing circuit 40 performs fault analysis.
After the processing device 50 outputs the component level signal, the group string level signal and the load level signal to the signal processing circuit 40, the signal processing circuit 40 outputs a first failure detection signal to the processing device 50 by the component level signal, and the failure state of the component level is reflected by the first failure detection signal. Under the action of the group cascade level signal, the signal processing circuit 40 outputs a second fault detection signal to the processing device 50, and the fault state of the group cascade can be reflected through the second fault detection signal. Under the action of the load level signal, the signal processing circuit 40 outputs a third fault detection signal to the processing device 50, and the fault state of the load level can be reflected by the third fault detection signal. Finally, the processing device 50 obtains whether the current photovoltaic system fails and the specific location of the current photovoltaic system by combining the specific condition analysis of the first fault detection signal, the second fault detection signal and the third fault detection signal, so as to realize fault location.
According to the photovoltaic equipment, a photovoltaic system is divided into a component level, a group string level and a load level, in the operation process of the photovoltaic system, component level electrical parameters corresponding to the component level, group string level electrical parameters corresponding to the group string level and load level electrical parameters corresponding to the load level are respectively collected, then the component level electrical parameters, the group string level electrical parameters, the load level electrical parameters and preset parameter thresholds are analyzed, and component level signals, group string level signals and load level signals are output to a signal processing circuit 40 of the photovoltaic system. Finally, the first fault detection signal output by the signal processing circuit 40 under the component level signal, the second fault detection signal output under the group string level signal, and the third fault detection signal output under the load level signal are combined to obtain whether the photovoltaic system is in fault or not and the specific position of the fault. Through the scheme, the fault detection of the photovoltaic system can be realized, the fault location can be carried out when the fault occurs, operation and maintenance personnel can conveniently and timely overhaul, and the working reliability of the photovoltaic equipment is effectively improved.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A fault detection circuit for a photovoltaic system, comprising:
the photovoltaic module comprises a module level parameter acquisition device, a photovoltaic module control device and a control device, wherein the module level parameter acquisition device is connected to the output end of a photovoltaic module of a photovoltaic system and is used for acquiring module level electrical parameters of the photovoltaic module;
the group cascade parameter acquisition device is connected to the output end of a photovoltaic string of the photovoltaic system and is used for acquiring group cascade electrical parameters of the photovoltaic string;
the load level parameter acquisition device is connected to the output end of a load of the photovoltaic system and is used for acquiring load level electrical parameters of the load;
a signal processing circuit;
the processing device is connected with the input end of the signal processing circuit, and the output end of the signal processing circuit is connected with the processing device;
the processing device is used for outputting a component level signal, a group cascade level signal and a load level signal to the signal processing circuit according to the component level electrical parameter, the group cascade electrical parameter, the load level electrical parameter and a preset parameter threshold; and fault positioning is carried out on the photovoltaic system according to a first fault detection signal output by the signal processing circuit under the component level signal, a second fault detection signal output by the group of cascade level signals and a third fault detection signal output by the load level signal.
2. The fault detection circuit of claim 1, wherein the signal processing circuit comprises a component-level signal processing circuit, a group serial-level signal processing circuit, and a load-level signal processing circuit, the component-level parameter acquisition device is connected to an input of the component-level signal processing circuit through the processing device, the group serial-level parameter acquisition device is connected to an input of the group serial-level signal processing circuit through the processing device, the load-level parameter acquisition device is connected to an input of the load-level signal processing circuit through the processing device, and an output of the component-level signal processing circuit, an output of the group serial-level signal processing circuit, and an input of the load-level signal processing circuit are all connected to the processing device.
3. The fault detection circuit of claim 2, wherein the output of the component-level signal processing circuit, the output of the group of serial-level signal processing circuits, and the output of the load-level signal processing circuit are connected to the processing device by multiplexing the same signal line;
and/or the component level parameter acquisition device, the group of serial level parameter acquisition devices and the load level parameter acquisition device are connected with the processing device by multiplexing the same signal line.
4. The fault detection circuit of claim 2, wherein the component-level signal processing circuit comprises a first comparator, a first switching device, and a first optocoupler device, a first input terminal of the first comparator serves as an input terminal of the component-level signal processing circuit, the second input end of the first comparator is connected with a power supply, the output end of the first comparator is connected with the control end of the first switching device, a first end of the first switching device is connected with a power supply, a second end of the first switching device is connected with a first end of a light emitter of the first optical coupler device, the second end of the light emitter of the first optical coupler is grounded, the first end of the light receiver of the first optical coupler is connected with a first power supply, and the second end of the light receiver of the first optical coupler device is used as the output end of the component level signal processing circuit.
5. The fault detection circuit of claim 4, wherein the set of cascode signal processing circuits includes a second comparator, a second switching device, and a second optocoupler device, a first input terminal of the second comparator serves as an input terminal of the set of cascaded signal processing circuits, a second input end of the second comparator is connected with a power supply, an output end of the second comparator is connected with a control end of the second switching device, a first end of the second switching device is connected with a power supply, a second end of the second switching device is connected with a first end of a light emitter of the second optocoupler device, the second end of the light emitter of the second optical coupler is grounded, the first end of the light receiver of the second optical coupler is connected with a second power supply, and the second end of the light receiver of the second optical coupler device is used as the output end of the group of serial-stage signal processing circuits.
6. The fault detection circuit of claim 5, wherein the load stage signal processing circuit comprises a third comparator, a third switching device, and a third optocoupler device, a first input terminal of the third comparator serves as an input terminal of the load stage signal processing circuit, a second input end of the third comparator is connected with a power supply, an output end of the third comparator is connected with a control end of the third switching device, a first end of the third switching device is connected with a power supply, a second end of the third switching device is connected with a first end of a light emitter of the third optical coupler device, the second end of the light emitter of the third optical coupler is grounded, the first end of the light receiver of the third optical coupler is connected with a third power supply, a second end of a light receiver of the third optical coupler device is used as an output end of the load-level signal processing circuit; the voltage values of the first power supply, the second power supply, and the third power supply are different from each other.
7. The fault detection circuit of claim 6, wherein the voltage value of the third power supply is greater than the voltage value of the second power supply, and wherein the voltage value of the second power supply is greater than the voltage value of the first power supply.
8. The fault detection circuit of any of claims 1-7, wherein the component level parameter acquisition device, the group string level parameter acquisition device, and the load level parameter acquisition device are leakage current sensors.
9. A photovoltaic system comprising a fault detection circuit as claimed in any one of claims 1 to 8.
10. A photovoltaic device comprising the photovoltaic system of claim 9.
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| CN115021324A (en) * | 2022-08-09 | 2022-09-06 | 阳光电源股份有限公司 | Confluence device, photovoltaic system and fault detection method |
| CN115021324B (en) * | 2022-08-09 | 2022-11-15 | 阳光电源股份有限公司 | Confluence device, photovoltaic system and fault detection method |
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