阅读说明：本技术 一种光伏电站的工作状态监测方法及系统 (Method and system for monitoring working state of photovoltaic power station ) 是由 孙洪山 姚连彬 郭曙光 赵雅丽 雷超 陈雷 翟顾丽 王建祥 陈啸 刘永琛 任兴星 于 2019-10-16 设计创作，主要内容包括：本发明主要公开了一种光伏电站的工作状态监测方法及系统,解决了温度因素对光伏电站的工作状态监测的影响,降低了其工作状态的误判率。本发明的方法及系统通过电流变化率与温度变化率的比值进行初步判断,同时利用电压变化率与温度变化率的比值进行辅助判断,经过初步与辅助判断的融合,来确定与汇流箱输入端相连的太阳能电池串或上一级汇流箱的工作状态是否正常,并且,通过在太阳能电池板的背光侧增加相变材料,来自适应调节太阳能电池板的温度,有效的降低了温度因素对光伏电站的工作状态监测的影响,提高了监测准确率,同时提高了太阳能电池板的光电转换效率。(The invention mainly discloses a method and a system for monitoring the working state of a photovoltaic power station, which solve the problem that the working state of the photovoltaic power station is monitored by temperature factors and reduce the misjudgment rate of the working state of the photovoltaic power station. The method and the system of the invention carry out primary judgment through the ratio of the current change rate to the temperature change rate, simultaneously carry out auxiliary judgment through the ratio of the voltage change rate to the temperature change rate, determine whether the working state of the solar cell string connected with the input end of the combiner box or the previous-stage combiner box is normal through the fusion of the primary judgment and the auxiliary judgment, and adaptively adjust the temperature of the solar cell panel by adding the phase change material on the backlight side of the solar cell panel, thereby effectively reducing the influence of the temperature factor on the monitoring of the working state of the photovoltaic power station, improving the monitoring accuracy and simultaneously improving the photoelectric conversion efficiency of the solar cell panel.)

1. A method for monitoring the operating state of a photovoltaic power plant, said photovoltaic power plant comprising at least one photovoltaic cell array, said photovoltaic cell array comprising a plurality of strings of monocrystalline silicon solar cells, at least one combiner box, said strings of monocrystalline silicon solar cells comprising a plurality of monocrystalline silicon solar panels, the input of each combiner box being connected to one solar cell string or to the output of a preceding combiner box, the output of said combiner box being connected to one input of a following combiner box or to an inverter, said method comprising:

detecting the current value and the voltage value of each input end of the combiner box in real time, and respectively calculating the current change rate and the voltage change rate according to the current value and the voltage value;

detecting the ambient temperature of the photovoltaic cell array in real time, and calculating the temperature change rate according to the ambient temperature;

calculating the ratio of the current change rate to the environmental temperature change rate and recording the ratio as R_I/TAccording to R_I/TWhether the working state of each monocrystalline silicon solar cell string/previous-stage junction box connected with the input end of the junction box is within a preset threshold value interval or not is preliminarily judged, and if R is within the preset threshold value interval, the working state of each monocrystalline silicon solar cell string/previous-stage junction box connected with the input end of the junction box is judged_I/TWithin a preset threshold interval, judging that the working state of the solar cell string/the previous-stage combiner box is normal, or judging that the working state of the solar cell string/the previous-stage combiner box is abnormal;

calculating a ratio R of the voltage change rate to the ambient temperature change rate_U/TAccording to R_U/TWhether the voltage is within a preset threshold interval or not is assisted to judge the working state of each monocrystalline silicon solar cell string/previous-stage junction box connected with the input end of the junction box, and if R is within the preset threshold interval, the working state of each monocrystalline silicon solar cell string/previous-stage junction box is assisted to judge the working state of each monocrystalline silicon solar cell string/previous_U/TWithin a preset threshold interval, judging that the working state of the solar cell string/the previous-stage combiner box is normal, or judging that the working state of the solar cell string/the previous-stage combiner box is abnormal;

if the working state results of the solar cell string/the previous-stage combiner box are judged preliminarily and auxiliarily to be different, the working state of the solar cell string/the previous-stage combiner box is judged to be abnormal directly, if the working states of the solar cell string/the previous-stage combiner box are judged preliminarily and auxiliarily to be the same and normal, the working state of the solar cell string/the previous-stage combiner box is judged finally to be normal, and if the working states of the solar cell string are judged preliminarily and auxiliarily to be the same and abnormal, the working state of the solar cell string/the previous-stage combiner box is judged finally to be abnormal.

2. The method of claim 1 for monitoring the operating condition of a photovoltaic power plant, further comprising:

and determining the abnormal type of the working state of the solar cell string/the previous-stage combiner box according to the current value and the voltage value input by the input end of the combiner box, and sending a corresponding alarm signal according to the abnormal type.

3. The method for monitoring the working state of the photovoltaic power plant as claimed in claim 2, wherein the determining the abnormal category of the working state of the solar cell string/the previous-stage combiner box and sending out the corresponding alarm signal comprises:

respectively acquiring the current variation and the voltage variation input by the input end of the combiner box;

comparing the current variation with an upper current threshold and a lower current threshold, wherein the upper current threshold is larger than the lower current threshold;

if the current variation is larger than the current upper limit threshold, determining that the abnormal category of the working state is current overflow, and sending a current overflow alarm signal;

if the current variation is smaller than the current lower limit threshold, determining that the abnormal type of the working state is insufficient current;

comparing the voltage variation with an upper voltage threshold and a lower voltage threshold, wherein the upper voltage threshold is larger than the lower voltage threshold;

if the voltage variation is larger than the upper voltage limit threshold, determining that the abnormal category of the working state is voltage overflow, and sending a voltage overflow alarm signal;

and if the voltage variation is smaller than the lower voltage limit threshold, determining that the abnormal category of the working state is insufficient voltage.

4. An operating condition monitoring system of a photovoltaic power station, the photovoltaic power station includes at least one photovoltaic cell array, the photovoltaic cell array includes a plurality of monocrystalline silicon solar cell cluster, at least one collection flow box, monocrystalline silicon solar cell cluster includes a plurality of monocrystalline silicon solar cell panel, every the input of collection flow box links to each other with a solar cell cluster or the output of last level collection flow box, the output of collection flow box links to each other with an input or the dc-to-ac converter of next level collection flow box, its characterized in that, the system includes:

the current detection unit is used for detecting the current value input by the input end of each combiner box in real time;

the voltage detection unit is used for detecting the voltage value input by the input end of each combiner box in real time;

the temperature detection unit is used for detecting the temperature value of the environment where the photovoltaic cell array is located in real time;

the data processing unit is used for respectively calculating the current change rate, the voltage change rate and the temperature change rate of the photovoltaic cell array according to the current value and the voltage value input by the input end of each combiner box and the temperature value of the environment where the photovoltaic cell array is located;

and the state judgment unit is used for judging the working state of each solar cell string by using the processing result of the data processing unit.

5. The system for monitoring the working condition of the photovoltaic power station as claimed in claim 4, wherein the temperature adaptive adjusting unit is characterized in that at least one metal box is arranged on the backlight side of the solar panel, and phase change materials are filled in the metal box; the phase-change material is common solid paraffin with the melting point of 50 ℃.

6. The system of claim 4 further comprising:

the temperature self-adaptive adjusting unit is used for carrying out self-adaptive temperature adjustment on the monocrystalline silicon solar panel, reducing the temperature change rate of the monocrystalline silicon solar panel and enabling the monocrystalline silicon solar panel to be in a temperature interval of efficient photoelectric conversion.

7. The system of claim 4 further comprising:

and the warning unit is used for determining the abnormal type of the working state of the solar cell string or the upper-stage combiner box after the state judgment unit judges that the working state of the solar cell string or the upper-stage combiner box is abnormal, and sending a corresponding warning signal according to the abnormal type.

8. The system for monitoring the operating condition of a photovoltaic power plant of claim 7, wherein the alarm signal sent by the alarm unit comprises:

if the current variation is larger than the current upper limit threshold, determining that the abnormal category of the working state is current overflow, and sending a current overflow alarm signal;

if the current variation is smaller than the current lower limit threshold, determining that the abnormal category of the working state is insufficient current, and sending an insufficient current alarm signal;

if the voltage variation is larger than the upper voltage limit threshold, determining that the abnormal category of the working state is voltage overflow, and sending a voltage overflow alarm signal;

and if the voltage variation is smaller than the lower voltage limit threshold, determining that the abnormal category of the working state is insufficient voltage, and sending an insufficient voltage alarm signal.

Technical Field

The invention relates to the technical field of photovoltaic power generation, in particular to a method and a system for monitoring the working state of a photovoltaic power station.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

With the rapid development of the photovoltaic industry, the proportion of photovoltaic power generation capacity in a regional power grid is larger and larger, development opportunities are brought to a power system, and meanwhile, new challenges are brought to various aspects such as safe and stable operation, dispatching control and the like of the power system, and effective monitoring of the working state of a photovoltaic power station is the basis of safe and stable and reasonable dispatching control of the power system.

In northwest areas of China, solar energy resources are rich, radiation intensity is high, large-scale centralized photovoltaic power stations develop rapidly, at present, the photovoltaic power stations mainly use crystalline silicon solar panels, which are very sensitive to temperature changes, when the temperature rises by 1 ℃, the maximum output power of the crystalline silicon solar panels drops by 0.04%, open-circuit voltage drops by 0.04%, and short-circuit current rises by 0.04%, meanwhile, the photoelectric conversion efficiency of the crystalline silicon solar panels is lower than 20%, most of the rest light energy is converted into heat energy, meanwhile, the natural environment in the northwest areas is very bad, the early-wearing jacket noon-crossing yarns surround a furnace, watermelon eating is vividly reflected in temperature changes in different time periods in the northwest areas, and due to the influence of temperature factors, misjudgment is easily generated on the working state of the photovoltaic power stations, and further a series of unnecessary losses are caused.

Most of the existing methods only consider the influence of dust and sunlight intensity on the working state of the photovoltaic power station, and do not consider the misjudgment of the working state of the photovoltaic power station caused by temperature factors.

Disclosure of Invention

The utility model discloses in order to solve the above-mentioned problem, a photovoltaic power plant's operating condition monitoring method and system is proposed, this disclosure carries out preliminary judgement through the ratio of current change rate and temperature change rate, utilize the ratio of voltage change rate and temperature change rate to carry out the auxiliary judgement simultaneously, through the integration of preliminary and auxiliary judgement, confirm with the working condition of the solar cell cluster that converges that the flow box input links to each other or the last one-level flow box that converges whether normal, and, through increasing phase change material in solar cell panel's the side of being shaded, the temperature of self-adaptation regulation solar cell panel, the effectual influence that reduces the temperature factor to photovoltaic power plant's operating condition monitoring, the monitoring accuracy has been improved, solar cell panel's photoelectric conversion efficiency has been improved simultaneously.

According to some embodiments, the following technical scheme is adopted in the disclosure:

a method for monitoring the working state of a photovoltaic power station, wherein the photovoltaic power station comprises at least one photovoltaic cell array, the photovoltaic cell array comprises a plurality of monocrystalline silicon solar cell strings and at least one combiner box, the monocrystalline silicon solar cell strings comprise a plurality of monocrystalline silicon solar panels, the input end of each combiner box is connected with one solar cell string or the output end of the combiner box at the previous stage, the output end of the combiner box is connected with one input end of the combiner box at the next stage or an inverter, and the monitoring method comprises the following steps:

detecting the current value and the voltage value of each input end of the combiner box in real time, and respectively calculating the current change rate and the voltage change rate according to the current value and the voltage value;

detecting the ambient temperature of the photovoltaic cell array in real time, and calculating the temperature change rate according to the ambient temperature;

calculating the ratio of the current change rate to the environmental temperature change rate and recording the ratio as R_I/TAccording to R_I/TWhether the working state of each monocrystalline silicon solar cell string/previous-stage junction box connected with the input end of the junction box is within a preset threshold value interval or not is preliminarily judged, and if R is within the preset threshold value interval, the working state of each monocrystalline silicon solar cell string/previous-stage junction box connected with the input end of the junction box is judged_I/TWithin a preset threshold interval, judging that the working state of the solar cell string/the previous-stage combiner box is normal, or judging that the working state of the solar cell string/the previous-stage combiner box is abnormal;

calculating a ratio R of the voltage change rate to the ambient temperature change rate_U/TAccording to R_U/TWhether the voltage is within a preset threshold interval or not is assisted to judge the working state of each monocrystalline silicon solar cell string/previous-stage junction box connected with the input end of the junction box, and if R is within the preset threshold interval, the working state of each monocrystalline silicon solar cell string/previous-stage junction box is assisted to judge the working state of each monocrystalline silicon solar cell string/previous_U/TWithin a preset threshold interval, judging that the working state of the solar cell string/the previous-stage combiner box is normal, or judging that the working state of the solar cell string/the previous-stage combiner box is abnormal;

if the working state results of the solar cell string/the previous-stage combiner box are judged preliminarily and auxiliarily to be different, the working state of the solar cell string/the previous-stage combiner box is judged to be abnormal directly, if the working states of the solar cell string/the previous-stage combiner box are judged preliminarily and auxiliarily to be the same and normal, the working state of the solar cell string/the previous-stage combiner box is judged finally to be normal, and if the working states of the solar cell string are judged preliminarily and auxiliarily to be the same and abnormal, the working state of the solar cell string/the previous-stage combiner box is judged finally to be abnormal.

Preferably, after determining that the working state of the solar cell string connected to the combiner box or the previous-stage combiner box is abnormal, the method further includes: and determining the abnormal type of the working state according to the current value and the voltage value input by the input end of the combiner box, and sending a corresponding alarm signal according to the abnormal type.

Preferably, the determining the abnormal type of the operating state according to the current value and the voltage value input by the input end of the combiner box and sending out a corresponding alarm signal according to the abnormal type includes:

respectively acquiring the current variation and the voltage variation input by the input end of the combiner box;

comparing the current variation with an upper current threshold and a lower current threshold, wherein the upper current threshold is larger than the lower current threshold;

if the current variation is larger than the current upper limit threshold, determining that the abnormal category of the working state is current overflow, and sending a current overflow alarm signal;

if the current variation is smaller than the current lower limit threshold, determining that the abnormal type of the working state is insufficient current;

comparing the voltage variation with an upper voltage threshold and a lower voltage threshold, wherein the upper voltage threshold is larger than the lower voltage threshold;

if the voltage variation is larger than the upper voltage limit threshold, determining that the abnormal category of the working state is voltage overflow, and sending a voltage overflow alarm signal;

and if the voltage variation is smaller than the lower voltage limit threshold, determining that the abnormal category of the working state is insufficient voltage.

An operating condition monitoring system of a photovoltaic power station, the photovoltaic power station includes at least one photovoltaic cell array, the photovoltaic cell array includes a plurality of monocrystalline silicon solar cell strings, at least one collection flow box, the monocrystalline silicon solar cell string includes a plurality of monocrystalline silicon solar cell panels, every the input of collection flow box links to each other with a solar cell string or the output of last level collection flow box, the output of collection flow box links to each other with an input or the dc-to-ac converter of next level collection flow box, monitoring system includes:

the current detection unit is used for detecting the current value input by the input end of each combiner box in real time;

the voltage detection unit is used for detecting the voltage value input by the input end of each combiner box in real time;

the temperature detection unit is used for detecting the temperature value of the environment where the photovoltaic cell array is located in real time;

the data processing unit is used for respectively calculating the current change rate, the voltage change rate and the temperature change rate of the photovoltaic cell array according to the current value and the voltage value input by the input end of each combiner box and the temperature value of the environment where the photovoltaic cell array is located;

and the state judgment unit is used for judging the working state of each solar cell string by using the processing result of the data processing unit.

Preferably, the system further comprises:

the temperature self-adaptive adjusting unit is used for carrying out self-adaptive temperature adjustment on the monocrystalline silicon solar panel, reducing the temperature change rate of the monocrystalline silicon solar panel and enabling the monocrystalline silicon solar panel to be in a temperature interval of efficient photoelectric conversion.

Further, the temperature self-adaptive adjusting unit is provided with at least one metal box on the backlight side of the solar panel, the metal box is internally provided with a phase change material, the phase change material is liquefied and absorbs heat when the temperature is higher than the melting point of the phase change material, and is solidified and released heat when the temperature is lower than the melting point of the phase change material.

Further, the phase change material is common solid paraffin.

Preferably, the system further comprises:

and the warning unit is used for determining the abnormal type of the working state of the solar cell string or the upper-stage combiner box after the state judgment unit judges that the working state of the solar cell string or the upper-stage combiner box is abnormal, and sending a corresponding warning signal according to the abnormal type.

Compared with the prior art, the beneficial effect of this disclosure is:

(1) according to the photovoltaic power station working state monitoring system, the temperature factor is introduced into the working state monitoring process of the photovoltaic power station, misjudgment of the working state of the photovoltaic power station due to the temperature factor is effectively avoided, and a series of unnecessary losses are avoided.

(2) The method utilizes the ratio of the current change rate to the temperature change rate as a primary judgment, the ratio of the voltage change rate to the temperature change rate as an auxiliary judgment, and the accuracy of the working state judgment result of the photovoltaic power station is improved through the fusion of the primary judgment and the auxiliary judgment.

(3) The temperature of the crystalline silicon solar panel is regulated and controlled by utilizing the phase-change material in a self-adaptive mode, the variation range of the temperature of the panel can be effectively reduced, the accuracy of the working state judgment result of a photovoltaic power station is improved, and the photoelectric conversion efficiency of the crystalline silicon solar panel can be improved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the application and, together with the description, serve to explain the application and are not intended to limit the application.

FIG. 1 is a schematic view of a partial structure of a photovoltaic power plant of the present disclosure;

FIG. 2 is a schematic diagram of a single crystal silicon solar cell panel structure with phase change material installed according to the present disclosure;

FIG. 3 is a flow chart of a method of monitoring the operating condition of a photovoltaic power plant of the present disclosure;

FIG. 4 is a schematic structural diagram of an operating condition monitoring system of a photovoltaic power plant of the present disclosure;

Detailed Description

The present disclosure is further described with reference to the following drawings and examples.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

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 example 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 it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

In the present disclosure, terms such as "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "side", "bottom", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only relational terms determined for convenience in describing structural relationships of the parts or elements of the present disclosure, and do not refer to any parts or elements of the present disclosure, and are not to be construed as limiting the present disclosure.

In the present disclosure, terms such as "fixedly connected", "connected", and the like are to be understood in a broad sense, and mean either a fixed connection or an integrally connected or detachable connection; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present disclosure can be determined on a case-by-case basis by persons skilled in the relevant art or technicians, and are not to be construed as limitations of the present disclosure.

In order to make the technical field better understand the scheme of the embodiment of the invention, the embodiment of the invention is further described in detail below with reference to the drawings and the implementation mode.

As shown in fig. 1, the partial structure of a photovoltaic power plant provided by the present disclosure only shows a part of a photovoltaic array composed of two-stage confluence, and in practical applications, the photovoltaic array can increase the confluence level according to the requirement. The connection mode of the photovoltaic array in this embodiment is: the solar cell strings are formed by n (n is more than or equal to 1) solar cell panels, n-type convergence boxes are adopted, namely n solar cell strings are respectively connected with different input ends of the same primary convergence box, the output end of the primary convergence box is respectively connected with the input end of the same secondary convergence box, and finally the integrated current is output by the secondary convergence box.

The embodiment of the present disclosure provides an operating condition monitoring method of a photovoltaic power station as shown in fig. 1, where the photovoltaic power station includes at least one photovoltaic cell array, the photovoltaic cell array includes a plurality of monocrystalline silicon solar cell strings and at least one combiner box, the monocrystalline silicon solar cell string includes a plurality of monocrystalline silicon solar cell panels, an input end of each combiner box is connected to one solar cell string or an output end of a previous combiner box, an output end of the combiner box is connected to one input end of a next combiner box or an inverter, and the operating condition monitoring method of the photovoltaic power station as shown in fig. 3 includes the following steps:

detecting the current value and the voltage value of each input end of the combiner box in real time, and respectively calculating the current change rate and the voltage change rate according to the current value and the voltage value;

detecting the ambient temperature of the photovoltaic cell array in real time, and calculating the temperature change rate according to the ambient temperature;

the temperature of a solar cell panel in a photovoltaic cell array is adjusted in a self-adaptive mode by using a phase change material, so that the monocrystalline silicon solar cell string is in a temperature interval of high-efficiency photoelectric conversion;

calculating the ratio of the current change rate to the environmental temperature change rate and recording the ratio as R_I/TAccording to R_I/TWhether the working state of each monocrystalline silicon solar cell string/previous-stage junction box connected with the input end of the junction box is within a preset threshold value interval or not is preliminarily judged, and if R is within the preset threshold value interval, the working state of each monocrystalline silicon solar cell string/previous-stage junction box connected with the input end of the junction box is judged_I/TWithin a preset threshold interval, judging that the working state of the solar cell string/the previous-stage combiner box is normal, or judging that the working state of the solar cell string/the previous-stage combiner box is abnormal;

calculating a ratio R of the voltage change rate to the ambient temperature change rate_U/TAccording to R_U/TWhether the voltage is within a preset threshold interval or not is assisted to judge the working state of each monocrystalline silicon solar cell string/previous-stage junction box connected with the input end of the junction box, and if R is within the preset threshold interval, the working state of each monocrystalline silicon solar cell string/previous-stage junction box is assisted to judge_I/TWithin a preset threshold interval, judging that the working state of the solar cell string/the previous-stage combiner box is normal, or judging that the working state of the solar cell string/the previous-stage combiner box is abnormal;

if the working state results of the solar cell string/the previous-stage combiner box are judged preliminarily and auxiliarily to be different, the working state of the solar cell string/the previous-stage combiner box is judged to be abnormal directly, if the working states of the solar cell string/the previous-stage combiner box are judged preliminarily and auxiliarily to be the same and normal, the working state of the solar cell string/the previous-stage combiner box is finally judged to be normal, and if the working states of the solar cell string/the previous-stage combiner box are judged preliminarily and auxiliarily to be the same and abnormal, the working state of the solar cell string/the previous-stage combiner box is finally judged to be abnormal.

Further, the current/voltage change rate is the change degree of the current/voltage value with time in unit time period Δ t; the temperature change rate is the change degree of the temperature value of the environment where the photovoltaic cell array is located in unit time period delta t along with time, the temperature change rate can reflect the temperature change condition in a period of time, the environment data under the real condition can be collected through the temperature sensor with low price, historical meteorological data does not need to be referred to or special meteorological data does not need to be purchased, the purchasing cost can be effectively reduced, and the embodiment has stronger practicability.

Further, the temperature adaptive adjustment unit is provided with at least one metal box on the backlight side of the solar panel, as shown in fig. 2, the metal box is internally provided with a phase change material, the metal box is arranged on the backlight side of the solar panel in a sticking manner, and the installation position of the metal box is the central position of the backlight side of the solar panel.

Furthermore, the phase change material is common solid paraffin, the melting point of the common solid paraffin is generally 50-75 ℃, the normal working temperature of the monocrystalline silicon solar panel is 48 +/-2 ℃, the common solid paraffin with the melting point of 50 ℃ is adopted in the embodiment, and the cost of the common solid paraffin is lower and can be ignored relative to the cost of the monocrystalline silicon solar panel, so that the influence of temperature factors on the monitoring of the working state of the photovoltaic power station is reduced while the cost of the photovoltaic cell array is not increased, and the photoelectric conversion efficiency of the solar panel is improved.

Furthermore, the preset threshold interval is set according to historical data of monitoring of the working state of the photovoltaic power station, the setting range of the threshold interval is greatly influenced by different regions and different environments, and the current/voltage of the input end of the combiner box in an ideal state is changedThe ratio of the change rate to the temperature change rate should be 1, but in consideration of the performance stability of the solar cell string and the header box and the accuracy of data acquisition, the threshold interval is set to [0.9,1.2 ] in this embodiment for the actual conditions in the northwest region]If the ratio R is_I/TWithin a preset threshold interval of 0.9,1.2]If not, judging that the working state of each monocrystalline silicon solar cell string/previous-stage combiner box connected with the input end of the combiner box is normal, otherwise, judging that the working state of each solar cell string/previous-stage combiner box is abnormal; further judging the ratio R_U/TIf the ratio R is_U/TWithin a preset threshold interval of 0.9,1.2]If the working state of each monocrystalline silicon solar cell string/previous-stage combiner box connected with the input end of the combiner box is normal, the working state of each monocrystalline silicon solar cell string/previous-stage combiner box connected with the input end of the combiner box is judged to be abnormal; if the working state results of the solar cell string/the previous-stage combiner box are judged preliminarily and auxiliarily to be different, the working state of the solar cell string/the previous-stage combiner box is judged to be abnormal directly, if the working states of the solar cell string/the previous-stage combiner box are judged preliminarily and auxiliarily to be the same and normal, the working state of the solar cell string/the previous-stage combiner box is finally judged to be normal, and if the working states of the solar cell string/the previous-stage combiner box are judged preliminarily and auxiliarily to be the same and abnormal, the working state of the solar cell string/the previous-stage combiner box is finally judged to be abnormal.

Preferably, after determining that the working state of the solar cell string connected to the combiner box or the previous-stage combiner box is abnormal, the method further includes: and determining the abnormal type of the working state according to the current value and the voltage value input by the input end of the combiner box, and sending a corresponding alarm signal according to the abnormal type.

Preferably, the determining the abnormal type of the operating state according to the current value and the voltage value input by the input end of the combiner box and sending out a corresponding alarm signal according to the abnormal type includes:

respectively acquiring the current variation and the voltage variation input by the input end of the combiner box;

comparing the current variation with an upper current threshold and a lower current threshold, wherein the upper current threshold is larger than the lower current threshold;

if the current variation is larger than the current upper limit threshold, determining that the abnormal category of the working state is current overflow, and sending a current overflow alarm signal;

if the current variation is smaller than the current lower limit threshold, determining that the abnormal type of the working state is insufficient current;

comparing the voltage variation with an upper voltage threshold and a lower voltage threshold, wherein the upper voltage threshold is larger than the lower voltage threshold;

if the voltage variation is larger than the upper voltage limit threshold, determining that the abnormal category of the working state is voltage overflow, and sending a voltage overflow alarm signal;

and if the voltage variation is smaller than the lower voltage limit threshold, determining that the abnormal category of the working state is insufficient voltage.

Correspondingly, an embodiment of the present disclosure further provides an operating condition monitoring system of a photovoltaic power station, as shown in fig. 4, the photovoltaic power station includes at least one photovoltaic cell array, the photovoltaic cell array includes a plurality of monocrystalline silicon solar cell strings and at least one combiner box, the monocrystalline silicon solar cell string includes a plurality of monocrystalline silicon solar cell panels, an input end of each combiner box is connected to an output end of one solar cell string or the previous combiner box, an output end of each combiner box is connected to an input end of the next combiner box or an inverter, and the monitoring system includes:

the current detection unit is used for detecting the current value input by the input end of each combiner box in real time;

the voltage detection unit is used for detecting the voltage value input by the input end of each combiner box in real time;

the temperature detection unit is used for detecting the temperature value of the environment where the photovoltaic cell array is located in real time;

the temperature self-adaptive adjusting unit is used for carrying out self-adaptive temperature adjustment on the monocrystalline silicon solar panel, reducing the temperature change rate of the monocrystalline silicon solar panel and enabling the monocrystalline silicon solar panel to be in a temperature interval of efficient photoelectric conversion;

the data processing unit is used for respectively calculating the current change rate, the voltage change rate and the temperature change rate of the photovoltaic cell array according to the current value and the voltage value input by the input end of each combiner box and the temperature value of the environment where the photovoltaic cell array is located;

and the state judgment unit is used for judging the working state of each solar cell string by using the processing result of the data processing unit.

Further, the temperature self-adaptive adjusting unit is characterized in that at least one metal box is arranged on the backlight side of the solar cell panel, and a phase change material is filled in the metal box.

Further, the phase change material is common solid paraffin.

Preferably, the system further comprises:

and the warning unit is used for determining the abnormal type of the working state of the solar cell string or the upper-stage combiner box after the state judgment unit judges that the working state of the solar cell string or the upper-stage combiner box is abnormal, and sending a corresponding warning signal according to the abnormal type.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.