CN115441407A - Short circuit perception protection system is prevented to photovoltaic cluster - Google Patents
Short circuit perception protection system is prevented to photovoltaic cluster Download PDFInfo
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- CN115441407A CN115441407A CN202211195301.5A CN202211195301A CN115441407A CN 115441407 A CN115441407 A CN 115441407A CN 202211195301 A CN202211195301 A CN 202211195301A CN 115441407 A CN115441407 A CN 115441407A
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- 230000002159 abnormal effect Effects 0.000 claims abstract description 29
- YHXISWVBGDMDLQ-UHFFFAOYSA-N moclobemide Chemical compound C1=CC(Cl)=CC=C1C(=O)NCCN1CCOCC1 YHXISWVBGDMDLQ-UHFFFAOYSA-N 0.000 claims abstract description 29
- 230000002265 prevention Effects 0.000 claims abstract description 21
- 230000005540 biological transmission Effects 0.000 claims abstract description 12
- 238000001514 detection method Methods 0.000 claims abstract description 12
- 238000006243 chemical reaction Methods 0.000 claims abstract description 10
- 238000012544 monitoring process Methods 0.000 claims abstract description 7
- 238000012545 processing Methods 0.000 claims description 16
- 238000005070 sampling Methods 0.000 claims description 8
- 238000005259 measurement Methods 0.000 claims description 5
- 230000005611 electricity Effects 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 13
- 238000010248 power generation Methods 0.000 abstract description 6
- 238000004458 analytical method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
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- 238000003491 array Methods 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
- H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02S—GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
- H02S50/00—Monitoring or testing of PV systems, e.g. load balancing or fault identification
- H02S50/10—Testing of PV devices, e.g. of PV modules or single PV cells
Abstract
A photovoltaic string short-circuit prevention perception protection system belongs to the technical field of photovoltaic power generation. The method is characterized in that: the intelligent switch is used for inputting the acquired bus temperature into a preset ARIMA model to predict future bus temperature change; collecting bus electrical item data, fitting the bus electrical item data and the predicted bus temperature, and reporting to a controller when the fitted data is abnormal; the temperature acquisition module is used for monitoring the bus temperature and sending the bus temperature to the intelligent switch, and the controller is used for controlling switching-on and switching-off tripping in the photovoltaic network according to the acquired abnormal data or carrying out secondary detection on the abnormal data; the interface conversion device is connected with the photovoltaic string, the interface conversion device is connected with the photovoltaic direct current transmission protection unit, and the photovoltaic direct current transmission protection unit is connected with the inverter. The invention solves the problems of detection blind area and unreliable short circuit protection in the traditional detection method, and greatly improves the safety of a photovoltaic string circuit system.
Description
Technical Field
A photovoltaic string short-circuit prevention perception protection system belongs to the technical field of photovoltaic power generation.
Background
Photovoltaic power generation has the characteristics of cleanness, renewability and the like, and is one of main forms of new energy. If the solar photovoltaic is not properly protected, a fault in the photovoltaic array can damage the photovoltaic modules and/or cables and cause a dc arc hazard and even a fire hazard. In recent years, photovoltaic power generation technology is rapidly developed, the characteristics of small capacity, dense points and dispersion are presented, and how to ensure the stable operation of the small photovoltaic power generation systems becomes a prominent problem. The complexity of the operation of the power grid is further increased, and the phenomenon of uncontrollable is easy to occur. Therefore, the method has important significance for improving the safety stability and efficiency of the photovoltaic power generation system by effectively detecting the faults in the photovoltaic array and designing a corresponding protection action scheme. In general, overcurrent protection is adopted for protecting a photovoltaic array in a mode of matching overcurrent protection with additional fuse to protect a photovoltaic module from overcurrent. When ground protected, the resulting large current activates the over-current protection device and breaks the fault circuit.
At present, there are some researches on line-to-line fault detection and protection in photovoltaic arrays, and mainly applicable methods include an energy loss method, a voltage-current waveform method, and the like. For example, the voltage-current waveform method is a relatively direct method, and utilizes the characteristics embodied by the voltage-current waveform to perform fault analysis, and is not influenced by environmental parameters; however, the waveform analysis of the fault by using the voltage and the current needs to be clear about the waveform characteristics of different faults in the photovoltaic array. However, the existing methods are complicated and they fail to distinguish the severity of the inter-lane fault.
Therefore, a simple and effective photovoltaic string short-circuit prevention sensing protection system is still needed in the current photovoltaic engineering.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the defects of the prior art are overcome, and a simple and effective photovoltaic string short-circuit prevention perception protection system is provided.
The technical scheme adopted by the invention for solving the technical problems is as follows: this short-circuit perception protection system is prevented to photovoltaic cluster, pass direct current protection unit and dc-to-ac converter, its characterized in that including intelligence switch, temperature acquisition module, controller, photovoltaic:
the intelligent switch is used for inputting the acquired bus temperature into a preset ARIMA model to predict the future bus temperature change; collecting bus electrical item data, fitting the bus electrical item data and the predicted bus temperature, and reporting to a controller when the fitted data is abnormal; the temperature acquisition module is used for monitoring the bus temperature and sending the bus temperature to the intelligent switch, and the controller is used for controlling switching-on and switching-off tripping in the photovoltaic network according to the acquired abnormal data or carrying out secondary detection on the abnormal data; the interface conversion device is connected with the photovoltaic string, the interface conversion device is connected with the photovoltaic direct current transmission protection unit, and the photovoltaic direct current transmission protection unit is connected with the inverter.
Preferably, the bus electric item data includes bus-side three-phase current, bus-side three-phase voltage, instantaneous reactive power, instantaneous active power, total power, three-phase voltage waveform distortion degree and three-phase current waveform distortion degree.
According to the preferable photovoltaic string short-circuit prevention perception protection system, before the intelligent switch inputs the acquired bus temperature to the ARIMA model, a bus temperature autocorrelation graph and a partial correlation graph are drawn; and then input into an ARIMA model.
According to the preferable photovoltaic string short-circuit prevention perception protection system, the ARIMA model judges whether the bus temperature is balanced according to the bus temperature autocorrelation graph and the partial correlation graph; and when in balance, determining the order of the ARIMA model according to the order of the autoregressive model and the order of the moving average model, and then predicting the future bus temperature change through the ARIMA model after the order is determined.
Preferably, the bus electrical item data further includes output voltage of the photovoltaic string, the output voltage of the photovoltaic string takes 1ms as a moving window, and a steady-state output voltage difference of the photovoltaic array before and after a fault is calculated for 10 sampling points within 1 ms.
Preferably, the photovoltaic string short-circuit prevention perception protection system comprises a photovoltaic direct current protection unit and a control unit, wherein the photovoltaic direct current protection unit comprises a hall sensor, a contactor and the control unit; each photovoltaic string is connected with a Hall sensor in series for current measurement, and the series contactor is used for disconnecting the photovoltaic string and finally feeding the photovoltaic string into an MPPT branch of the inverter; the control unit is used for the implementation of the protection logic.
Preferably, the photovoltaic string short-circuit prevention sensing protection system comprises a controller, a compensation and AD sampling circuit, a Digital Signal Processor (DSP), and a control loop.
Preferably, the photovoltaic string short-circuit prevention perception protection system comprises an intelligent switch and a control module, wherein the intelligent switch comprises a data acquisition module, a processing module and a switching-on/off module; the data acquisition module acquires bus electrical item data and sends the bus electrical item data to the processing module; the processing module predicts future bus temperature change through a preset ARIMA model; fitting the bus electrical item data and the predicted bus temperature, and reporting the data to a controller when the fitted data is abnormal; the switching-on and switching-off module is used for executing corresponding switching-on and switching-off operations after the controller sends a switching-on and switching-off instruction; and the controller sends the switching-on and switching-off command and then forwards the switching-on and switching-off command to the switching-on and switching-off module through the processing module.
Preferably, in the photovoltaic string short-circuit prevention perception protection system, the controller uses electrical quantity data as a main criterion and non-electrical quantity data as an auxiliary criterion, and when the main criterion and the auxiliary criterion are both abnormal, the controller controls the switching-on/off module in the photovoltaic network to trip; when the main criterion and the auxiliary criterion are different and abnormal, the controller controls the intelligent switch to continue monitoring. The controller is used for controlling the tripping of a switching-on/off module in the photovoltaic network or carrying out secondary detection on abnormal data according to the acquired abnormal data.
Compared with the prior art, the photovoltaic string short-circuit prevention perception protection system has the beneficial effects that: the invention provides a photovoltaic string short-circuit protection system based on low-voltage photovoltaic temperature sensing, wherein each photovoltaic string is connected with a Hall sensor in series for current measurement, and a contactor is connected in series for disconnecting the photovoltaic string and finally feeding the photovoltaic string into an MPPT branch of an inverter; the control unit is used for the implementation of the protection logic. The control unit comprises a compensation and AD sampling circuit of direct current, a digital operation processor DSP and a control loop. According to the short-circuit protection method based on the data sensed by the low-voltage photovoltaic temperature, the problems that a traditional detection method has a detection blind area and the short-circuit protection is unreliable are solved by combining remote detection with local data and combining main criteria with auxiliary criteria, and the safety of a photovoltaic string circuit system is greatly improved.
Detailed Description
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, and furthermore, the terms "comprises" and "having", and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.
The invention is further illustrated by the following specific examples, of which example 1 is the best mode of practice.
Example 1
The invention discloses a photovoltaic string short-circuit prevention perception protection system, which comprises an intelligent switch, a temperature acquisition module, a controller, a photovoltaic direct current transmission protection unit and an inverter, wherein the intelligent switch is connected with the temperature acquisition module; the intelligent switch is used for inputting the acquired bus temperature into a preset ARIMA model to predict future bus temperature change; the intelligent switch comprises a data acquisition module, a processing module and a switching-on/off module; the data acquisition module acquires bus electrical item data and sends the bus electrical item data to the processing module; the processing module predicts future bus temperature change through a preset ARIMA model; fitting the bus electrical item data and the predicted bus temperature, and reporting the data to a controller when the fitted data is abnormal; the switching-on and switching-off module is used for executing corresponding switching-on and switching-off operations after the controller sends a switching-on and switching-off instruction; and the controller sends the switching-on and switching-off command and then forwards the switching-on and switching-off command to the switching-on and switching-off module through the processing module. Before the intelligent switch inputs the acquired bus temperature to the ARIMA model, firstly, drawing a bus temperature autocorrelation graph and a partial correlation graph; and then input into an ARIMA model.
Acquiring bus electrical item data, fitting the bus electrical item data and the predicted bus temperature, and reporting to a controller when the fitted data is abnormal; the bus electric item data comprises bus side three-phase current, bus side three-phase voltage, instantaneous reactive power, instantaneous active power, total power, three-phase voltage waveform distortion degree and three-phase current waveform distortion degree. The bus electrical item data further comprises the output voltage of the photovoltaic string, the output voltage of the photovoltaic string takes 1ms as a moving window, and the steady-state output voltage difference value of the photovoltaic array before and after the fault is calculated for 10 sampling points within 1 ms.
The controller is used for controlling switching-on and switching-off tripping in the photovoltaic network according to the acquired abnormal data or carrying out secondary detection on the abnormal data; the interface conversion device is connected with the photovoltaic string, the interface conversion device is connected with the photovoltaic direct current transmission protection unit, and the photovoltaic direct current transmission protection unit is connected with the inverter.
The controller comprises a compensation and AD sampling circuit of direct current, a digital operation processor DSP and a control loop. The controller takes the electrical quantity data as a main criterion and takes the non-electrical quantity data as an auxiliary criterion, and when the main criterion and the auxiliary criterion are both abnormal, the controller controls the switching-on/off module in the photovoltaic network to trip; when the main criterion and the auxiliary criterion are different and abnormal, the controller controls the intelligent switch to continue monitoring.
The ARIMA model judges whether the bus temperature is balanced according to the bus temperature autocorrelation graph and the partial correlation graph; and when in balance, determining the order of the ARIMA model according to the order of the autoregressive model and the order of the moving average model, and then predicting the future bus temperature change through the ARIMA model after the order is determined. The photovoltaic direct-current protection unit comprises a Hall sensor, a contactor and a control unit; each photovoltaic string is connected with a Hall sensor in series for current measurement, and the series contactor is used for disconnecting the photovoltaic string and finally feeding the photovoltaic string into an MPPT branch of the inverter; the control unit is used for the implementation of the protection logic.
Example 2
The invention discloses a photovoltaic string short-circuit prevention perception protection system, which comprises an intelligent switch, a temperature acquisition module, a controller, a photovoltaic direct current transmission protection unit and an inverter, wherein the intelligent switch is connected with the temperature acquisition module; the intelligent switch is used for inputting the acquired bus temperature into a preset ARIMA model to predict future bus temperature change; the intelligent switch comprises a data acquisition module, a processing module and a switching-on/off module; the data acquisition module acquires bus electrical item data and sends the bus electrical item data to the processing module; the processing module predicts future bus temperature change through a preset ARIMA model; fitting the bus electrical item data and the predicted bus temperature, and reporting the data to a controller when the fitted data is abnormal; the switching-on and switching-off module is used for executing corresponding switching-on and switching-off operations after the controller sends a switching-on and switching-off instruction; and the controller sends the switching-on and switching-off command and then forwards the switching-on and switching-off command to the switching-on and switching-off module through the processing module. Before the intelligent switch inputs the acquired bus temperature to the ARIMA model, firstly, a bus temperature autocorrelation graph and a partial correlation graph are drawn; and then input into an ARIMA model.
Acquiring bus electrical item data, fitting the bus electrical item data and the predicted bus temperature, and reporting to a controller when the fitted data is abnormal; the bus electric item data comprises bus side three-phase current, bus side three-phase voltage, instantaneous reactive power, instantaneous active power, total power, three-phase voltage waveform distortion degree and three-phase current waveform distortion degree.
The controller is used for controlling switching-on and switching-off tripping in the photovoltaic network according to the acquired abnormal data or carrying out secondary detection on the abnormal data; the interface conversion device is connected with the photovoltaic string, the interface conversion device is connected with the photovoltaic direct current transmission protection unit, and the photovoltaic direct current transmission protection unit is connected with the inverter.
The controller comprises a compensation and AD sampling circuit of direct current, a digital operation processor DSP and a control loop. The controller takes the electrical quantity data as a main criterion and takes the non-electrical quantity data as an auxiliary criterion, and when the main criterion and the auxiliary criterion are both abnormal, the controller controls the switching-on/off module in the photovoltaic network to trip; when the main criterion and the auxiliary criterion are different and abnormal, the controller controls the intelligent switch to continue monitoring.
The ARIMA model judges whether the bus temperature is balanced according to the bus temperature autocorrelation graph and the partial correlation graph; and when in balance, determining the order of the ARIMA model according to the order of the autoregressive model and the order of the moving average model, and then predicting the future bus temperature change through the ARIMA model after the order is determined. The photovoltaic direct-current protection unit comprises a Hall sensor, a contactor and a control unit; each photovoltaic string is connected with a Hall sensor in series for current measurement, and the series contactor is used for disconnecting the photovoltaic string and finally feeding the photovoltaic string into an MPPT branch of the inverter; the control unit is used for the implementation of the protection logic.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. However, any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present invention will still fall within the protection scope of the technical solution of the present invention.
Claims (9)
1. The utility model provides a short-circuit perception protection system is prevented to photovoltaic cluster, passes direct current protection unit and dc-to-ac converter, its characterized in that including intelligence switch, temperature acquisition module, controller, photovoltaic:
the intelligent switch is used for inputting the acquired bus temperature into a preset ARIMA model to predict future bus temperature change; acquiring bus electrical item data, fitting the bus electrical item data and the predicted bus temperature, and reporting to a controller when the fitted data is abnormal; the temperature acquisition module is used for monitoring the bus temperature and sending the bus temperature to the intelligent switch, and the controller is used for controlling switching-on and switching-off tripping in the photovoltaic network according to the acquired abnormal data or carrying out secondary detection on the abnormal data; the interface conversion device is connected with the photovoltaic string, the interface conversion device is connected with the photovoltaic direct current transmission protection unit, and the photovoltaic direct current transmission protection unit is connected with the inverter.
2. The photovoltaic string short-circuit prevention perception protection system of claim 1, characterized in that:
the bus electric item data comprise bus side three-phase current, bus side three-phase voltage, instantaneous reactive power, instantaneous active power, total power, three-phase voltage waveform distortion degree and three-phase current waveform distortion degree.
3. The photovoltaic string short-circuit prevention perception protection system of claim 1, characterized in that:
before the intelligent switch inputs the acquired bus temperature to an ARIMA model, firstly, drawing a bus temperature autocorrelation graph and a partial correlation graph; and then input into an ARIMA model.
4. The photovoltaic string short-circuit prevention perception protection system of claim 3, characterized in that:
the ARIMA model judges whether the bus temperature is balanced according to the bus temperature autocorrelation graph and the partial correlation graph; and when in balance, determining the order of the ARIMA model according to the order of the autoregressive model and the order of the moving average model, and then predicting the future bus temperature change through the ARIMA model after the order is determined.
5. The photovoltaic string short-circuit prevention perception protection system of claim 1, characterized in that:
the bus electricity item data further comprises the output voltage of the photovoltaic string, the output voltage of the photovoltaic string takes 1ms as a moving window, and the steady-state output voltage difference value of the photovoltaic array before and after the fault is calculated for 10 sampling points within 1 ms.
6. The photovoltaic string short-circuit prevention perception protection system of claim 1, characterized in that:
the photovoltaic direct current protection unit comprises a Hall sensor, a contactor and a control unit; each photovoltaic string is connected with a Hall sensor in series for current measurement, and a series contactor is used for disconnecting the photovoltaic string and finally feeding the photovoltaic string into an MPPT branch of the inverter; the control unit is used for the implementation of the protection logic.
7. The photovoltaic string short-circuit prevention perception protection system of claim 7, characterized in that:
the controller comprises a direct current compensation and AD sampling circuit, a digital operation processor (DSP) and a control loop.
8. The photovoltaic string short-circuit prevention perception protection system of claim 1, characterized in that:
the intelligent switch comprises a data acquisition module, a processing module and a switching-on/off module;
the data acquisition module acquires bus electrical item data and sends the bus electrical item data to the processing module;
the processing module predicts future bus temperature change through a preset ARIMA model; fitting the bus electrical item data and the predicted bus temperature, and reporting the data to a controller when the fitted data is abnormal;
the switching-on and switching-off module is used for executing corresponding switching-on and switching-off operations after the controller sends a switching-on and switching-off instruction; and the controller sends the switching-on and switching-off command and then forwards the switching-on and switching-off command to the switching-on and switching-off module through the processing module.
9. The photovoltaic string short-circuit prevention perception protection system of claim 1, characterized in that:
the controller takes the electrical quantity data as a main criterion and takes the non-electrical quantity data as an auxiliary criterion, and when the main criterion and the auxiliary criterion are both abnormal, the controller controls the switching-on/off module in the photovoltaic network to trip; when the main criterion and the auxiliary criterion are different and abnormal, the controller controls the intelligent switch to continue monitoring.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211195301.5A CN115441407A (en) | 2022-09-28 | 2022-09-28 | Short circuit perception protection system is prevented to photovoltaic cluster |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202211195301.5A CN115441407A (en) | 2022-09-28 | 2022-09-28 | Short circuit perception protection system is prevented to photovoltaic cluster |
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