CN104779912A

CN104779912A - Method and system for monitoring working state of solar photovoltaic power station

Info

Publication number: CN104779912A
Application number: CN201510209484.5A
Authority: CN
Inventors: 杨盛楠
Original assignee: Beijing Hanergy Solar Power Investment Co Ltd
Current assignee: Dongjun new energy Co.,Ltd.
Priority date: 2015-04-28
Filing date: 2015-04-28
Publication date: 2015-07-15
Anticipated expiration: 2035-04-28
Also published as: CN104779912B

Abstract

The invention discloses a method and system for monitoring the working state of a solar photovoltaic power station and belongs to the technical field of solar photovoltaic power generation. According to the method and system, whether the working state of a solar cell string connected with an input end or the working state of a superior combiner box is abnormal or not is determined by verifying the ratio of the current change rate to the sunlight intensity change rate, verifying the current values of adjacent or close input ends, verifying the following coefficients of the current change rates of the adjacent or close input ends and verifying the number of the current change rates, not followed, of the adjacent or close input ends, and the monitoring accuracy is high.

Description

A kind of work state monitoring method of solar photovoltaic power plant and system

Technical field

The present invention relates to solar photovoltaic technology field, particularly a kind of work state monitoring method of solar photovoltaic power plant and system.

Background technology

Solar-energy photo-voltaic cell array in solar photovoltaic power plant and the line between inverter is various, line loss is large, and the solar panel used in the industry is of a great variety, component parameter aspect differs greatly, for different designs scheme, also multi-form inverter can be adopted, thus making in actual applications according to the difference of project, the arrangement mode of photovoltaic array is varied.Differ greatly based on group string operating characteristic each in photovoltaic array, therefore very difficult single foundation component characteristic or arrangement mode delimited to the operating state of solar cell string (or being called group string) and determined number range, and this just brings huge difficulty to the Real-Time Monitoring of photovoltaic array and failure diagnosis.Due to the basic comprising unit that group string is solar-energy photo-voltaic cell array, and whether group string normally works the gross generation of the safety and photovoltaic plant that directly have influence on photovoltaic plant, therefore, the real-time current of each group of string to be monitored and failure diagnosis just seems particularly important.

In prior art, conventional monitoring system mainly realizes the remote monitoring of the electric quantity signal to solar photovoltaic power plant, specifically, just the different pieces of information of electric quantity signal is shown at the same window, and directly can not form comparing result; Also part monitoring system is had can to monitor according to the working condition of current changing rate to photovoltaic plant in group string, but when there is interference in the external world in this kind of monitoring system, such as solar cell string is subject to object and blocks or under the cloud of sailing the situation such as to block, easily cause monitoring result to occur mistake.

Summary of the invention

Embodiments provide a kind of work state monitoring method and system of solar photovoltaic power plant, effectively improve monitoring accuracy.

The technical scheme that the embodiment of the present invention provides is as follows:

On the one hand, provide a kind of work state monitoring method of solar photovoltaic power plant, described solar photovoltaic power plant comprises at least one solar-energy photo-voltaic cell array, described solar-energy photo-voltaic cell array comprises multiple solar cell string and has the header box of multiple input and an output, the input of each described header box is connected with the output of a solar cell string or upper level header box, and described method comprises:

The current value of each input of real-time detection, and according to described current value calculating current rate of change;

The intensity of sunshine of each input of real-time detection, and calculate intensity of sunshine rate of change according to described intensity of sunshine;

Calculate the ratio of described current changing rate and described intensity of sunshine rate of change;

Judge described ratio whether in predetermined threshold value interval, if not, then determine that the operating state of solar cell string or the upper level header box be connected with described input is abnormal, otherwise carry out next step and judge;

Judge whether that the current value of all adjacent or close input of described header box is all less than the first preset value, if, then determine that the operating state of solar cell string or the upper level header box be connected with described input is normal, otherwise enter next step judgement;

The current value judging whether to exist certain input is less than or equal to the second preset value and the current value of adjacent or close other inputs one or more is more than or equal to the first preset value, wherein said first preset value is greater than described second preset value, if, then determine that the solar cell string that this input connects or upper level header box are in abnormal operation, otherwise calculate the ratio of the current changing rate of described input and the current changing rate of the input adjacent or close with described input and enter next step and judge;

Judge whether the ratio of the current changing rate of described input and the current changing rate of the input adjacent or close with described input is greater than default current following variation coefficient, if, then determine the solar cell string that is connected with described input or upper level header box operating state abnormal, otherwise current following variation coefficient is greater than the input quantity of described default current following variation coefficient in adding up the input adjacent or close with described input, if described input quantity is less than the 3rd preset value, then determine that the operating state of solar cell string or the upper level header box be connected with described input is abnormal.

Preferably, if the input quantity that in the input adjacent or close with described input, current following variation coefficient is greater than described default current following variation coefficient is not less than the 3rd preset value, then determine that the operating state of solar cell string or the upper level header box be connected with described input is normal.

Preferably, after determining that the operating state of solar cell string or the upper level header box be connected with described input is abnormal, described method also comprises: send corresponding alarm signal according to abnormal class.

Preferably, corresponding alarm signal is sent according to abnormal class, comprise: compared with null value alarm threshold, lower current limit threshold value and upper current limit threshold value respectively by the current value of described input, described lower current limit threshold value is greater than described null value alarm threshold and is less than described upper current limit threshold value;

If the current value of described input is less than described null value alarm threshold, then determines that the abnormal class of described operating state is that null value is reported to the police, and send null value alarm signal;

If the current value of described input is greater than described null value alarm threshold and be less than described lower current limit threshold value, then determine that the abnormal class of described operating state is that electric current low value is out-of-limit, and send electric current low value off-limit alarm signal;

If the current value of described input is greater than described upper current limit threshold value, then determine that the abnormal class of described operating state is that electric current high level is out-of-limit, and send electric current high level off-limit alarm signal.

Preferably, if the ratio of described current changing rate and described intensity of sunshine rate of change is positive number, then judge whether the ratio of described current changing rate and described intensity of sunshine rate of change is less than the first predetermined threshold value, if so, then judge that the ratio of described current changing rate and described intensity of sunshine rate of change is in predetermined threshold value interval; If the ratio of described current changing rate and described intensity of sunshine rate of change is negative, then judge whether the ratio of described current changing rate and described intensity of sunshine rate of change is greater than the second predetermined threshold value, if so, then judge that the ratio of described current changing rate and described intensity of sunshine rate of change is in predetermined threshold value interval; Wherein said first predetermined threshold value is positive number, and described second predetermined threshold value is negative.

On the other hand, provide a kind of working state monitoring system of solar photovoltaic power plant, described solar photovoltaic power plant comprises at least one solar-energy photo-voltaic cell array, described solar-energy photo-voltaic cell array comprises multiple solar cell string and has the header box of multiple input and an output, the input of each described header box is connected with the output of a solar cell string or upper level header box, and described system comprises:

Current detection module, for detecting the current value of each input in real time;

First computing module, for according to described current value calculating current rate of change;

Intensity of sunshine detection module, for detecting the intensity of sunshine of each input in real time;

Second computing module, for calculating intensity of sunshine rate of change according to described intensity of sunshine;

3rd computing module, for calculating the ratio of described current changing rate and described intensity of sunshine rate of change;

Comparison module, for respectively the ratio of described current changing rate with described intensity of sunshine rate of change being compared with predetermined threshold value interval, or the current value of described input is compared with the first preset value or the second preset value, or the ratio of the current changing rate of the current changing rate of described input and the input adjacent or close with described input is compared with the current following variation coefficient preset, or the input quantity that current following variation coefficient in the input adjacent or close with described input is greater than described default current following variation coefficient is compared with the 3rd preset value, wherein said first preset value is greater than described second preset value,

First judge module, for judging that the ratio of described current changing rate and described intensity of sunshine rate of change is whether in predetermined threshold value interval;

Second judge module, for when described first judge module judged result is for being, judges whether that the current value of all adjacent or close inputs is all less than the first preset value further;

3rd judge module, for when described second judge module judged result is no, the current value that the current value judging whether to exist certain input is further less than or equal to the simultaneously adjacent or close input of the second preset value is more than or equal to the first preset value;

4th computing module, for when described 3rd judge module judged result is no, calculates the ratio of the current changing rate of described input and the current changing rate of the input adjacent or close with described input;

4th judge module, for when described 3rd judge module judged result is no, judge whether the ratio of the current changing rate of described input and the current changing rate of the input adjacent or close with described input is greater than default current following variation coefficient further;

Statistical module, adds up current following variation coefficient in the input adjacent or close with described input and is greater than the input quantity of default current following variation coefficient;

5th judge module, for judging whether the described input quantity that described statistical module counts obtains is less than the 3rd preset value;

Determination module, whether abnormal for determining the operating state of solar cell string or the upper level header box be connected with described input according to described first judge module, described second judge module, described 3rd judge module and the judged result of described 4th judge module, described 5th judge module.

Preferably, said system also comprises classification alarm module, for after determining that the operating state of solar cell string or the upper level header box be connected with described input is abnormal, sends corresponding alarm signal according to described abnormal class.

Preferably, described classification alarm module comprises:

Comparing unit, for being compared with null value alarm threshold, lower current limit threshold value and upper current limit threshold value respectively by the current value of described input, described lower current limit threshold value is greater than described null value alarm threshold and is less than described upper current limit threshold value;

Classification alarm unit, for when the current value of described input is less than described null value alarm threshold, determines that the abnormal class of described operating state is that null value is reported to the police, and sends null value alarm signal; When the current value of described input is greater than described null value alarm threshold and is less than described lower current limit threshold value, determine that the abnormal class of described operating state is that electric current low value is out-of-limit, and send electric current low value off-limit alarm signal; When the current value of described input is greater than described upper current limit threshold value, determine that the abnormal class of described operating state is that electric current high level is out-of-limit, and send electric current high level off-limit alarm signal.

Preferably, described first judge module comprises:

First judging unit, for judging whether the ratio of described current changing rate and described intensity of sunshine rate of change is positive number;

Second judging unit, after judging that the ratio of described current changing rate and described intensity of sunshine rate of change is positive number at described first judging unit, judge whether the ratio of described current changing rate and described intensity of sunshine rate of change is less than the first predetermined threshold value, if so, then judge that the ratio of described current changing rate and described intensity of sunshine rate of change is in predetermined threshold value interval;

Described second judging unit, also for after judging that the ratio of described current changing rate and described intensity of sunshine rate of change is not as positive number at described first judging unit, judge whether the ratio of described current changing rate and described intensity of sunshine rate of change is greater than the second predetermined threshold value, if so, then judge that the ratio of described current changing rate and described intensity of sunshine rate of change is in predetermined threshold value interval; Described first predetermined threshold value is positive number, and described second predetermined threshold value is negative.

The work state monitoring method of the solar photovoltaic power plant that the embodiment of the present invention provides and system, first the operating state of solar cell string or the upper level header box be connected with this input is determined according to current changing rate and the ratio of intensity of sunshine rate of change, if the ratio of current changing rate and intensity of sunshine rate of change exceedes predetermined threshold value interval, the power generation level then proving the solar cell string that connects of input or upper level header box does not synchronously change with environmental condition, but not the curent change that causes of environmental factor must cause for the short circuit of solar cell string or upper level header box itself or open circuit, thus detected the abnormal operation such as open circuit or short circuit, and under the condition synchronously changed at electric current and the intensity of sunshine of input, if the current value of all adjacent or close inputs is identified as shade when being all less than the first preset value and blocks, still judge that operating state is normal, if and the current value of certain input be in the current value of the simultaneously adjacent or close input of low-level high-level more than one time, although all there is synchronous change with intensity of sunshine in the electric current of these inputs, but because power generation level gap is excessive, and the solar cell string that the input determining to be in reduced levels connects or upper level header box break down, if the current value of input is all in high-level state, or part is in high-level state, part is in the low-level state of " can accept ", then further by current following variation coefficient, the electric current of input is checked whether to follow the curent change of adjacent or close input, if do not follow change, then determine that the solar cell string that input connects or upper level header box break down, if follow change, then determine verification basis, what utilize adjacent or close input follows the operating state that quantity (namely not following the input quantity of change) that variation coefficient exceeds preset value judges solar cell string or the upper level header box be connected with this input.Like this by the generation current data detected in real time with can reflect that the intensity of sunshine data of ambient conditions combine and monitor, and utilize the mutual verification of current changing rate of the mutual verification of the current value of adjacent or close input, adjacent or close input, the erroneous judgement that dependence and the external interference of historical data are caused can be reduced, thus effectively improve monitoring accuracy.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment below, apparently, the accompanying drawing that the following describes is only some embodiments recorded in the present invention, for those of ordinary skill in the art, other accompanying drawing can also be obtained according to these accompanying drawings.

Fig. 1 is the structural representation of a kind of solar photovoltaic power plant that the embodiment of the present invention provides;

Fig. 2 is the flow chart of the work state monitoring method of a kind of solar photovoltaic power plant that the embodiment of the present invention provides;

Fig. 3 is the structural representation of the working state monitoring system of a kind of solar photovoltaic power plant that the embodiment of the present invention provides.

Embodiment

In order to the scheme making those skilled in the art person understand the embodiment of the present invention better, below in conjunction with drawings and embodiments, the embodiment of the present invention is described in further detail.

As shown in Figure 1, be a part for a kind of solar photo-voltaic power generation station that the embodiment of the present invention provides, namely illustrate only two-stage and to conflux the part of photovoltaic array of composition, in actual applications, this photovoltaic array can continue increase and to conflux rank.In the present embodiment, in photovoltaic array, assembly connecting mode is: x (x >=1) solar panel forms a solar cell string, the one-level adopting n to enter 1 is confluxed, input 1 to the input n ganging up same one-level header box by n solar cell confluxes, the secondary simultaneously adopting m to enter 1 again confluxes, the electric current exported by the output of m one-level header box is confluxed by input 1 to the input m of same secondary header box, and finally unification is exported by the output of secondary header box.I represents the current value of each input input of header box.I represents the output current value of header box output.N represents the maximum solar cell string quantity that one-level header box can access, as being 8 enter 1 one-level header box for model, there are at most 8 inputs, accessible at most 8 solar cell strings, it is different that the one-level header box different when reality uses actually may access solar cell string quantity when exact arrangement, connect solar cell string as Z1-H1 header box reality is only connected to 7 inputs, Z1-H2 header box is actual is connected with 6 input solar cell strings.M represent secondary header box connect the maximum branch road quantity that can access, as being 10 enter 1 secondary header box for model, having at most 10 inputs, the output of 10 one-level header boxs can be connected at most.If one-level header box is 8 models entering, so this 10 electric current entering each input of secondary header box of 1 output that will be an one-level header box, be 8 solar cell crosstalk streams and, the output current of whole secondary header box be at most 80 solar cell crosstalk streams and.The solar cell string quantity difference that the secondary header box different when reality uses may actually access when exact arrangement, as Z1 header box reality is only connected to 9 one-level header boxs, the input 1 of Z1 header box connects the output of Z1-H1 header box, the input 2 of Z1 header box connects the output of Z1-H2 header box, the like.Or except being connected with one-level header box, also there is the input directly connecting solar cell string in Z1 header box.That is, for one-level header box Z1-H1 to Z1-Hm, in n input of one-level header box, multiple or whole input and solar cell are contacted and are connect, and allow one-level header box to there is vacant input; And for secondary header box Z1, have at least an input to be connected other input with the output of one-level header box to contact with solar cell and connect, or as shown in Figure 1 secondary header box all with input 1 to input m be connected with one-level header box Z1-H1 to Z1-Hm respectively, and allow to there is vacant input.The header box of higher level the like until N level (N is integer and N >=2).

In the photovoltaic array that in the present embodiment, solar power station adopts, each subcircuits of header box at different levels has following relation:

1, for one-level header box: for Z1-H1 header box, the electric current of its output and the current value of input have following relation: I _zI-H1=i ₁₁+ i ₁₂+ ... + i _1n.Z1-H1 header box has n input, and each input only connects a string solar cell string, so the current value of its each input be exactly separately connect the electric current of solar cell string, that is: i _{input 1}=i ₁₁.

2, for secondary header box: for Z1 header box, the current value of its output and the current value of input have following relation: I _zI=i ₁+ i ₂+ ... + i _m.Wherein, i ₁for the input current value of the input 1 of secondary header box Z1, this current value equals the output current value I of the output of one-level header box Z1-H1 _zI-H1, i ₂to i _mthe like.Z1 header box has m input, each input connects an one-level header box, so the current value of each input of secondary header box Z1 is exactly the current value of the output of the one-level header box connected separately, be actually n solar cell crosstalk flow valuve and, that is: the i of secondary header box _{input 1}=i ₁=I _zI-H1=i ₁₁+ i ₁₂+ ... + i _1n, i _{input m}=i _m=I _zI-Hm=i _m1+ i _m2+ ... + i _mn.And if both there is the input directly connecting solar cell string in Z1 header box, also there is the input connecting one-level header box, then the current value of the output of Z1 header box equals the current value sum of the current value of the solar cell string be directly connected with it and the output of each one-level header box.

For the header box of the higher level of N > 2, account form the like, no longer describe in detail herein.The electric current of the output of N level header box, through the access grid-connected point of inverter, enters power supply grid.

When header box normally works, easily detect the current value of each input of header box, because the output of each input with a solar cell string or higher level's header box is connected, therefore, the current value reality of each input is also the current value flowing through solar cell string or the higher level's header box be connected with this header box.

Due to the basic comprising unit that solar cell is solar photovoltaic power plant, a solar cell string is formed by after multiple solar cell series connection, for different solar photovoltaic power plants, the arrangement mode of photovoltaic array may have relatively big difference, because the quantity of solar-energy photo-voltaic cell string is more, one or more header box can be adopted to be confluxed by the energy output of solar cell string, therefore, ensureing that each solar cell string and header box can normally work is the prerequisite ensureing that solar photovoltaic power plant normally works.

In embodiments of the present invention, the input of " adjacent or close " refers to the solar cell string of connection or the adjacent or close input of upper level header box physical location, such as Z1-H1 header box in FIG, many the inputs although be separated by between the input 1 of this header box and input n, if but the solar cell string physical location that the solar cell string that input 1 connects is connected with input n is adjacent or close, then represent that input 1 is adjacent with input n or close.The solar cell string that physical location is adjacent or close or header box experience the change of identical illumination condition substantially, and the shade that the shade such as simultaneously experiencing building blocks process or successively experience same building thing blocks.

Embodiments provide a kind of work state monitoring method of solar photovoltaic power plant as shown in Figure 1, wherein, solar photovoltaic power plant comprises at least one solar-energy photo-voltaic cell array, solar-energy photo-voltaic cell array comprises multiple solar cell string and has the header box of multiple input and an output, the input of each header box is connected with the output of a solar cell string or upper level header box, the work state monitoring method of this solar photovoltaic power plant as shown in Figure 2, comprises the following steps:

Step 101: the current value detecting each input in real time, and according to current value calculating current rate of change.Wherein, current changing rate is the abbreviation of current value rate over time, and after detecting the current value in two moment respectively, those skilled in the art easily calculate current changing rate.

Step 102: the intensity of sunshine detecting each input in real time, and calculate intensity of sunshine rate of change according to intensity of sunshine.

Above-mentioned intensity of sunshine is also referred to as amplitude at sunshine, for certain solar cell string, from t ₀moment is to the intensity of sunshine rate of change=(intensity of sunshine of t _(t)-intensity of sunshine _(t0))/intensity of sunshine _(t0).Rate of change can reflect the situation of change at sunshine in a period of time.By the intensity of sunshine data of each input of Real-Time Monitoring, more real environmental data can not only be gathered, also do not need with reference to history gas phase data or buy special gas phase data, effectively reducing purchase cost, and make present embodiment have stronger exploitativeness.

Step 103: the ratio of calculating current rate of change and intensity of sunshine rate of change.Step 201 and subsequent step is entered after the ratio obtaining current changing rate, intensity of sunshine rate of change, current changing rate and intensity of sunshine rate of change.

Step 201: judge that the ratio of current changing rate and intensity of sunshine rate of change is whether in predetermined threshold value interval, if not, then illustrate that generating state and the intensity of sunshine of the solar cell string that this input connects or upper level header box change asynchronous, enter step 206: determine that the operating state of solar cell string or the upper level header box be connected with input is abnormal.That is, if the ratio of current changing rate and intensity of sunshine rate of change exceedes predetermined threshold value (comprising forward to exceed with negative sense more than two kinds of situations), prove that the generating state of above-mentioned solar cell string is not along with the intensity of illumination of environment synchronously changes, and under normal circumstances, what affect the power generation level change of solar cell string only has environmental factor, now can judge the solar cell string that input connects or upper level header box fault.Such as, at solar cell string, under the trouble-free state of header box, ideally the current changing rate of input and the ratio of intensity of sunshine rate of change should be 1, consider the stability of solar cell string and header box, this ratio should close in a threshold interval of 1, if in section, intensity of sunshine rate of change is 1.2 (namely illumination condition improves gradually) sometime, and the current changing rate of certain input reaches 1.5, significantly more than the hoisting velocity of intensity of sunshine, now can determine the fault that there is short circuit, and the current changing rate of certain input is only 1.02, be starkly lower than the hoisting velocity of intensity of sunshine, now can determine the fault that there is open circuit.

Wherein, judge whether the ratio of current changing rate and intensity of sunshine rate of change specifically comprises in predetermined threshold value interval:

Judge whether ratio is positive number, if so, then when ratio is less than the first predetermined threshold value, judge that ratio is in predetermined threshold value interval; Otherwise, when ratio is greater than the second predetermined threshold value, judge that ratio is in predetermined threshold value interval; Wherein, the first predetermined threshold value is positive number, and the second predetermined threshold value is negative.

If the judged result of step 201 is yes, then illustrate that the current value of input and intensity of sunshine are that basic synchronization changes, such as, to block or in darkness process at generation building effects, because intensity of sunshine reduces, then the electric current of input also reduces gradually.But, the synchronous change of this electric current and intensity of sunshine does not also mean that to there is fault scarcely, such as in midnight's time-division, the energy output of all solar cell strings remains zero all substantially, the single solar panels in solar cell string or solar cell string are now had to there occurs open circuit, along with the arrival in early morning, illumination condition improves gradually, and the solar cell string that this breaks down or the curent change of header box still change synchronous with intensity of sunshine.Therefore, in order to detect fault further, when the judged result of step 201 is for being, also need to enter step 202 and subsequent step detects further.

Step 202: judge whether that the current value of all adjacent or close input of header box is all less than the first preset value.First preset value is greater than the second hereinafter described preset value.

If the judged result of step 202 is yes, then illustrate and now do not have the current value of input to reach or the level higher more than (the first predetermined value), now the solar cell string that connects of all inputs or header box be all in one lower, even close to zero generating state.Due to all adjacent or close solar cell strings, the probability that open circuit fault occurs header box is simultaneously minimum, now can think and cause all solar cell strings normal power generation reason to be not that the solar cell string that these adjacent or close inputs connect all is blocked by shade, or be all in the sun set after dark state, therefore enter step 207: determine that the solar cell string that the input of this header box connects or upper level header box are in normal operating conditions, but not malfunction, the mutual verification of the current value of adjacent or close input is so just utilized to eliminate fault misdescription.

If the judged result of step 202 is no, then enters step 203 and judge further: the current value judging whether to exist certain input is less than or equal to the second preset value and the current value of adjacent or close other inputs one or more is more than or equal to the first preset value.

If the judged result of step 203 is yes, then in adjacent or close input, the current value of some inputs reaches or more than the first preset value, illustrate that the environmental condition in this moment certain limit can meet good power generation requirements, and now there is the current value of input lower than the second preset value, then think that the current value of this input is very low even close to zero.There is low-level generating state when environmental condition is good, then can judge that the solar cell string that this input connects or upper level header box are in abnormal operation.That is, in step 203, utilize the mutual verification of the current value of adjacent or close input, have identified good environmental condition and detected the input occurring exception, thus correctly inspection is out of order.

When the judged result of step 203 is no, there are two kinds of situations:

The first situation: the current value of all inputs reaches a high level, namely more than the first predetermined value;

The second situation: the current value of the input had is in the low-level state of " can accept ", is namely between the first predetermined value and the second predetermined value, and the current value of other input reaches a high level.

The operating state that above-mentioned two situations might not represent solar cell string or header box is normal, such as in the first case, likely occurred the short circuit of the single part (such as between two solar panels) in solar cell string, but short circuit among a small circle is also not enough to cause the curent change of the input of header box and intensity of sunshine to change obviously there is deviation; And in the second situation, likely occurred that open circuit appears in the single part in solar cell string, but this open circuit is also not enough to cause the curent change of the input of header box and intensity of sunshine to change there is obvious deviation.Therefore, when the judged result of step 203 is no, step 204 and subsequent step judgement is proceeded.

Step 204: the ratio calculating the current changing rate of input and the current changing rate of the input adjacent or close with input, is called current following variation coefficient at this by this ratio.

Such as in step 204, if all inputs of one-level header box Z1-H1 are all adjacent or close, then the current following variation coefficient of input 1 is i ₁₁/ i ₁₂, or i ₁₁/ i ₁₃deng.

Step 205: judge the ratio of the current changing rate of input and the current changing rate of the input adjacent or close with input (namely, current following variation coefficient) whether be greater than default current following variation coefficient, if so, then step 206 is entered: determine that the operating state of solar cell string or the upper level header box be connected with input is abnormal; If not, then enter step 207: determine that the operating state of solar cell string or the upper level header box be connected with input is normal, or adopt other detection method of the prior art to detect further.

When the ratio of the current changing rate of an input and the current changing rate of the input adjacent or close with this input is greater than default current following variation coefficient, although illustrate that the curent change of this input changes synchronous with intensity of sunshine, and current value and adjacent or close input are also no abnormal after checking, but adjacent or close input of comparing, the curent change of this input is more violent, now just can determine that the solar cell string that the input with more violent current changing rate connects or upper level header box there occurs the failure exception such as open circuit or short circuit.Such as, one-level header box Z1-H1 has 10 inputs and each connection solar cell string, the solar cell string only having input 1 to connect there occurs short circuit, but the solar cell of this fault was ganged up after one-level header box Z1-H1 is connected to the input 1 of secondary header box Z1, this input 1 of secondary header box Z1 is owing to being also connected to 9 normal solar cell strings, now the curent change of this input 1 of secondary header box Z1 remains and to change synchronous (synchronously improve or reduce) with intensity of sunshine, but now this input 1 of secondary header box Z1 " does not follow " adjacent or close input 2, input 3 changes, therefore by the verification of the current changing rate of adjacent or close input, the operating state of the one-level header box Z1-H1 that the input 1 having detected secondary header box Z1 connects is abnormal.If the electric current of input both synchronously changed with intensity of sunshine, followed again the curent change of other adjacent or close input well, then illustrated that operating state is normal.

When the judged result of step 205 is no, illustrate that creating good curent change as the input and adjacent or close input that judge object follows.Now using this input as a benchmark, step 301 and subsequent treatment can be carried out to the curent change of the input adjacent or close with this input further.

Step 301: add up current following variation coefficient in the input adjacent or close with described input (namely in step 205 as the input judging object, this input is as a benchmark) and be greater than the input quantity of default current following variation coefficient.Such as, through the judgement of step 205, the current changing rate of the input 4 of one-level header box Z1-H1 and the ratio of intensity of sunshine rate of change normal, input 4 and adjacent or close input 5, the current value difference of input 6 is normal, the current changing rate of input 4 and adjacent or close input 5, the ratio (i.e. current following variation coefficient) of the current changing rate of input 6 is normal, then using input 4 as a benchmark, calculate the input 1 adjacent or close with input 4, input 5, current following variation coefficient (the i.e. ratio of the current changing rate of input 5 and the current changing rate of input 4 of input 6 grade, the ratio etc. of input 6 and the current changing rate of input 4) in be greater than the quantity of default current following variation coefficient, input 5, input 6, the current following variation coefficient of input 7 is all greater than the words of default current following variation coefficient, the input quantity then counted in step 301 is 3.Visible, in step 301, " described input " refers to as the input judging object in step 204, and as the input of objects of statistics in step 301, be with as judging the input that the input of object is adjacent or close.

After acquisition input quantity, enter step 302: judge whether input quantity is less than the 3rd preset value.If described input quantity is less than the 3rd preset value, then enter step 206: determine that the operating state of solar cell string or the upper level header box be connected with these inputs is abnormal.Such as, 3rd preset value is 4, and only have the current following variation coefficient of input 5, input 6 and input 7 to exceed default current following variation coefficient, between the input that one-level header box Z1-H1 is described, major part is in good following state, and the solar cell string that the not good input of sub-fraction following state connects can be confirmed as exception.If input quantity is greater than the 3rd preset value, such as input 5, input 6 is until all there is not well following of curent change in input 15, input quantity is more than 4, now think that this situation of well not following on a large scale is that environmental factor causes, such as thinner cloud is sailed, all solar cell strings are all in good generating state in the process, but other solar cell string can not be followed well by the solar cell string that cloud is inswept and realize curent change, now enter step 207: determine that the solar cell string that these inputs connect is in normal operating conditions.

In embodiments of the present invention, after the operating state of the solar cell string determining to be connected with input or upper level header box is abnormal, the work state monitoring method of above-mentioned solar photovoltaic power plant also comprises alarming step 401: the abnormal class determining operating state, and sends corresponding alarm signal according to abnormal class.It is abnormal etc. that the current changing rate judged in the abnormal or step 302 of the curent change followability that the current value gap of the adjacent or close input that Exception Type comprises the current changing rate judged in step 201 and intensity of sunshine rate of change synchronism is abnormal, judge in step 203 is abnormal, judge in step 205 does not follow quantity.

The abnormal class of the above-mentioned current value determination operating state according to input, and send corresponding alarm signal according to abnormal class, except current value verifies exception, current following variation coefficient verification exception etc. mutually, also comprise:

Step S1: obtain the current value of input at predetermined time and current time respectively, calculate the current change quantity of input;

Step S2: current change quantity is compared with upper current limit threshold value, lower current limit threshold value respectively, upper current limit threshold value is greater than lower current limit threshold value;

If current change quantity is greater than upper current limit threshold value, and be greater than h times of predetermined time current value, h is greater than 0 and is less than 1, then perform step S3: determine that the abnormal class of operating state is that electric current high level is out-of-limit, and send electric current high level off-limit alarm signal;

If current change quantity is less than lower current limit threshold value, and be less than l times of predetermined time current value, l is greater than 0 and is less than 1, then perform step S4: determine that the abnormal class of operating state is that electric current low value is out-of-limit, and send electric current low value off-limit alarm signal.

In one embodiment of the invention, according to the abnormal class of the current value determination operating state of input, and send corresponding alarm signal according to abnormal class, also comprise:

Step S11: the current value of current time is compared with null value alarm threshold, null value alarm threshold is less than lower current limit threshold value;

If the current value of the current time of input is less than null value alarm threshold, then perform step S12: determine that the abnormal class of operating state is that null value is reported to the police, and send null value alarm signal.

In order to be described in detail to the embodiment of the present invention, first provide the definition of several base quantity below, and in conjunction with base quantity further to a preferred embodiment of the present invention will be described in detail.

(1) input electric current: the actual current value referring to each input of header box;

(2) warning remote signalling amount: carry out internal calculation according to gathered analog signals, exports digital remote signalling amount (0 or 1), and different digital remote signalling amounts represents different implications;

(3) whether null value is reported to the police: be zero according to input electric current, determine whether to send alarm signal, " 0 " represents this input institute connected components and does not work, 1 to represent this input institute connected components in running order, wherein, assembly mainly comprises the solar cell string be made up of multiple solar cell;

(4) electric current low value is out-of-limit: represent that input electric current is in the minimizing by a relatively large margin of current time generation current value, " 0 " represents this input institute connected components electric current and almost do not change, and is in normal operating conditions; " 1 " represents this input institute connected components electric current and occurs to change by a relatively large margin, is in abnormal working position;

(5) electric current high level is out-of-limit: represent that input electric current is in the increase by a relatively large margin of current time generation current value, " 0 " represents this input institute connected components electric current and almost do not change, and is in normal operating conditions; " 1 " represents this input institute connected components electric current and occurs to change by a relatively large margin, is in abnormal working position;

Below respectively null value is reported to the police, electric current high level is out-of-limit and electric current low value is out-of-limit is described in detail:

(3) null value is reported to the police:

In embodiments of the present invention, by judging whether input current value is 0, can judge whether input normally works.If in same header box institute connected components, any one input is stable exports generation current, and the some input current values be under this header box are 0, then this current value be 0 input send " null value warning ", thus remind this input end to there is fault.Because some input of same header box normally works; illustrate that weather condition possesses power generation conditions at that time; and now the input electric current of certain input is " 0 "; the all solar cell strings connect under this input is described all do not generate electricity, and belong to abnormal conditions, its reason is varied certainly; protection fuse as organized string series connection damages or in group string, certain assembly damages; or this group is serially connected with problem etc., concrete fault be discharged, need to detect assembly further.

Specifically can according to actual needs, arrange the condition that null value is reported to the police, such as, can arrange when input electric current meets the following conditions, the condition sending " null value warning " signal (i.e. remote signalling amount set) is:

1, arrange an adjustable null value warning initiation value effective value q, when in same header box, a branch current is greater than q arbitrarily, null value warning function just comes into operation;

2, arrange an adjustable null value to report to the police effective thresholding g, when the electric current of any one group string input is less than g, being considered as this branch current is 0, sends " null value warning ".

In embodiments of the present invention, due under normal circumstances, photovoltaic module exports relatively stable, do not have fixing operating current, output current changes with the change of irradiation (intensity of sunshine), under normal circumstances, the irradiation of sunlight is steady and continuous change, and affects by diffusion etc., and transition can not occur, therefore, under normal circumstances, group crosstalk stream is relatively stable, can not suddenly change, when having fault or damaging, will there is significant change in its output current.Therefore, can judge whether group string normally works by test set string real-time current variable quantity.

Out-of-limit for (4) electric current low value:

Judge whether that input electric current is undergone mutation exceeded normal limit by comparing the variable quantity of current value within the time arranged, judged whether group string normally works.If when having multichannel that the larger transition of electric current occurs in same header box simultaneously, now think that exception does not appear in the solar cell string that is connected with input or header box, and may be have object to block or cloud is sailed and caused, now, do not send abnormal alarm signal.

When input electric current meets the following conditions, send " electric current low value is out-of-limit " and report to the police, namely electric current low value out-of-limit remote signalling amount set (putting 1) condition is:

1, arrange sunshine amplitude to follow variation coefficient R1 and calculate changes in amplitude rate at current sunshine, if sunshine, changes in amplitude rate was negative value, and sunshine changes in amplitude rate and the absolute value of ratio of input current changing rate exceed set amplitude at sunshine and follow variation coefficient, so the out-of-limit coefficient of electric current high level puts 1; Known in conjunction with the changes in amplitude coefficient at sunshine in (4) and (5), when ratio is not in predetermined threshold value interval, then determine that the operating state of solar cell string or the upper level header box be connected with input is abnormal, according to sunshine amplitude change rate positive and negatively can determine that low value is out-of-limit or high level is out-of-limit.

2, genetic coefficient S (integer is simultaneously set, represent input comparison range around), arrange and compare input and follow variation coefficient B1, calculate the ratio of other input current changing rates around this input, when this ratio exceed set input follow variation coefficient time, the out-of-limit coefficient of electric current high level puts 1.

The out-of-limit coefficient l of electric current low value (also becoming lower current limit threshold value) 3, is set: namely during the l times of input current change quantity lower than electric current, sends " electric current low value is out-of-limit " and report to the police.

As (i _{n (0)}-i _{n (t)}) <I _min=li _{n (0)}, the off-limit alarm of output current low value; Wherein, l is electric current low value limit coefficient, l ∈ (0,1), this variable is by background maintenance software design patterns, and with monitoring backstage real time communication, n is integer, represent certain loop in header box, n is fan-in to the maximum, and t is certain loop, timer periods, this variable is by background maintenance software design patterns, and adjustable range is carried out difference according to disparity items and arranged.

Out-of-limit for (5) electric current high level:

Judging whether that input electric current is undergone mutation by comparing the variable quantity of current value within the time arranged, having exceeded normal limit, judged whether group string normally works.

When input electric current meets the following conditions, send " electric current high level is out-of-limit " and report to the police, namely the out-of-limit remote signalling amount of the electric current high level condition of 1 of putting is:

1, calculate changes in amplitude rate at current sunshine, if sunshine changes in amplitude rate be on the occasion of, and sunshine changes in amplitude rate and the absolute value of ratio of input current changing rate exceed set amplitude at sunshine and follow variation coefficient R2, so the out-of-limit coefficient of electric current high level puts 1;

2, arrange and compare input and follow variation coefficient B2, calculate the ratio of other input current changing rates around this input, when this ratio exceed set input follow variation coefficient time, the out-of-limit coefficient of electric current low value puts 1.

The out-of-limit coefficient h of electric current high level (also referred to as upper current limit threshold value) 3, is set: namely during the h times of input current change quantity higher than electric current, outputting alarm remote signalling.

As (i _{n (t)}-i _{n (0)}) >I _max=hi _{n (0)}, output current high level Threshold Crossing Alert remote signalling, wherein, h is electric current high level limit coefficient, h ∈ (0,1), this variable, by background maintenance software design patterns, has read-write window, can be directly downloaded in equipment by 485 order wires, and not needing programming program again, n is integer, represents certain loop in header box, n is actual circuitry number to the maximum, and t is certain loop, timer periods, this variable is by background maintenance software design patterns, and adjustable range is carried out difference according to disparity items and arranged.

The work state monitoring method of the solar photovoltaic power plant that the embodiment of the present invention provides, first the operating state of solar cell string or the upper level header box be connected with this input is determined according to current changing rate and the ratio of intensity of sunshine rate of change, if the ratio of current changing rate and intensity of sunshine rate of change exceedes predetermined threshold value interval, the power generation level then proving the solar cell string that connects of input or upper level header box does not synchronously change with environmental condition, but not the curent change that causes of environmental factor must cause for the short circuit of solar cell string or upper level header box itself or open circuit, thus detected the abnormal operation such as open circuit or short circuit, and under the condition synchronously changed at electric current and the intensity of sunshine of input, if the current value of all adjacent or close inputs is identified as shade when being all less than the first preset value and blocks, still judge that operating state is normal, if and the current value of certain input be in the current value of the simultaneously adjacent or close input of low-level high-level more than one time, although all there is synchronous change with intensity of sunshine in the electric current of these inputs, but because power generation level gap is excessive, and the solar cell string that the input determining to be in reduced levels connects or upper level header box break down, if the current value of input is all in high-level state, or part is in high-level state, part is in the low-level state of " can accept ", then further by current following variation coefficient, the electric current of input is checked whether to follow the curent change of adjacent or close input, if do not follow change, then determine that the solar cell string that input connects or upper level header box break down, if follow change, using the normal input of current following variation coefficient as benchmark, the quantity of adjacent or close input generation current following variation coefficient exception is compared, if only well do not followed on a small quantity, then directly determine exception, if a large amount of input is not all well followed, then judge that this phenomenon producing cause is such environmental effects, determine normal.Such as the solar cell string that cloud shade is inswept, portion's packet chain is left shade and to be blocked and portion's packet chain is not left shade and blocked, then relative to the group string not leaving shade and block, the solar cell string blocked that leaves having some " does not follow " curent change not leaving the solar cell string blocked well, but these group strings remain normal.Due to by the generation current detected in real time data with can reflect that the intensity of sunshine data of ambient conditions combine and monitor, and utilize the multiple mutual verification of adjacent close input, the erroneous judgement that dependence and the external interference of historical data are caused can be reduced, thus effectively improve monitoring accuracy.

Correspondingly, the embodiment of the present invention additionally provides a kind of working state monitoring system of solar photovoltaic power plant, as shown in Figure 3, solar photovoltaic power plant comprises at least one solar-energy photo-voltaic cell array, solar-energy photo-voltaic cell array comprises multiple solar cell string and has the header box of multiple input and an output, the input of each header box is connected with the output of a solar cell string or upper level header box, and described system comprises:

Current detection module 501, for detecting the current value of each input in real time;

First computing module 502, for the current value calculating current rate of change obtained according to current detection module 501;

Intensity of sunshine detection module 503, for detecting the intensity of sunshine of each input in real time;

Second computing module 504, calculates intensity of sunshine rate of change for the intensity of sunshine obtained according to intensity of sunshine detection module 503;

3rd computing module 505, the ratio of the intensity of sunshine rate of change that current changing rate and the second computing module 504 for calculating the first computing module 502 acquisition obtain;

Comparison module 506, current changing rate for being obtained by the 3rd computing module 505 respectively compares with predetermined threshold value interval with the ratio of intensity of sunshine rate of change, or the current value of the input obtained by current detection module 501 compares with the first preset value or the second preset value, or the ratio of the current changing rate of the input obtained by the 4th computing module 510 and the current changing rate of the input adjacent or close with this input compares with the current following variation coefficient preset, or the input quantity that in the input adjacent or close with this input obtained by statistical module 512, current following variation coefficient is greater than default current following variation coefficient compares with the 3rd preset value, wherein the first preset value is greater than the second preset value,

First judge module 507, for judging that the ratio of the current changing rate that the 3rd computing module 505 obtains and intensity of sunshine rate of change is whether in predetermined threshold value interval;

Second judge module 508, for when the first judge module 507 judged result is for being, judges whether that the current value of all adjacent or close input that current detection module 501 obtains all is less than the first preset value further;

3rd judge module 509, for when the second judge module 508 judged result is no, the current value that the current value judging whether to exist certain input is further less than or equal to the simultaneously adjacent or close input of the second preset value is more than or equal to the first preset value;

4th computing module 510, for when the 3rd judge module 509 judged result is no, calculate the ratio (that is, current following variation coefficient) of the current changing rate of described input and the current changing rate of the input adjacent or close with described input;

4th judge module 511, for when the 3rd judge module 509 judged result is no, and after the 4th computing module 510 obtains ratio, whether the ratio (that is, current following variation coefficient) of the current changing rate of the described input of further judgement and the current changing rate of the input adjacent or close with described input is greater than default current following variation coefficient;

Statistical module 512, when the 4th judge module judged result is no, adds up current following variation coefficient in the input adjacent or close with described input and is greater than the input quantity of default current following variation coefficient;

5th judge module 513, for judging whether the input quantity that described statistical module 512 statistics obtains is less than the 3rd preset value;

Determination module 514, whether abnormal for determining the operating state of solar cell string or the upper level header box be connected with described input according to described first judge module 507, described second judge module 508, described 3rd judge module 509 and the judged result of described 4th judge module 511, the 5th judge module 513.

As preferred embodiment, said system also comprises classification alarm module 515, after determining that at determination module 514 operating state of solar cell string or the upper level header box be connected with described input is abnormal, sends corresponding alarm signal according to abnormal class.

Classification alarm module 515 comprises:

Comparing unit 516, for being compared with null value alarm threshold, lower current limit threshold value and upper current limit threshold value respectively by the current value of described input, described lower current limit threshold value is greater than described null value alarm threshold and is less than described upper current limit threshold value;

Classification alarm unit 517, for when the current value of described input is less than described null value alarm threshold, determines that the abnormal class of described operating state is that null value is reported to the police, and sends null value alarm signal; When the current value of described input is greater than described null value alarm threshold and is less than described lower current limit threshold value, determine that the abnormal class of described operating state is that electric current low value is out-of-limit, and send electric current low value off-limit alarm signal; When the current value of described input is greater than described upper current limit threshold value, determine that the abnormal class of described operating state is that electric current high level is out-of-limit, and send electric current high level off-limit alarm signal.

As preferred embodiment, the first judge module 507 comprises:

The working state monitoring system of the solar photovoltaic power plant that the embodiment of the present invention provides, can reduce due to the method achieved in Fig. 2 the erroneous judgement caused dependence and the external interference of historical data, thus effectively improve monitoring accuracy.

Each embodiment in this specification all adopts the mode of going forward one by one to describe, between each embodiment identical similar part mutually see, what each embodiment stressed is the difference with other embodiments.Especially, for system embodiment, because it is substantially similar to embodiment of the method, so describe fairly simple, relevant part illustrates see the part of embodiment of the method.System embodiment described above is only schematic, the wherein said module that illustrates as separating component or unit or can may not be and physically separate, parts as unit display can be or may not be physical location, namely can be positioned at a place, or also can be distributed on multiple unit.Some or all of module wherein can be selected according to the actual needs to realize the object of the present embodiment scheme.Those of ordinary skill in the art, when not paying creative work, are namely appreciated that and implement.

The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1. the work state monitoring method of a solar photovoltaic power plant, described solar photovoltaic power plant comprises at least one solar-energy photo-voltaic cell array, described solar-energy photo-voltaic cell array comprises multiple solar cell string and has the header box of multiple input and an output, the input of each described header box is connected with the output of a solar cell string or upper level header box, it is characterized in that, described method comprises:

2. the work state monitoring method of solar photovoltaic power plant according to claim 1, it is characterized in that, if the input quantity that in the input adjacent or close with described input, current following variation coefficient is greater than described default current following variation coefficient is not less than the 3rd preset value, then determine that the operating state of solar cell string or the upper level header box be connected with described input is normal.

3. the work state monitoring method of solar photovoltaic power plant according to claim 1, it is characterized in that, after determining that the operating state of solar cell string or the upper level header box be connected with described input is abnormal, described method also comprises: send corresponding alarm signal according to abnormal class.

4. the work state monitoring method of solar photovoltaic power plant according to claim 3, it is characterized in that, corresponding alarm signal is sent according to abnormal class, comprise: compared with null value alarm threshold, lower current limit threshold value and upper current limit threshold value respectively by the current value of described input, described lower current limit threshold value is greater than described null value alarm threshold and is less than described upper current limit threshold value;

5. the work state monitoring method of solar photovoltaic power plant according to claim 1, it is characterized in that, if the ratio of described current changing rate and described intensity of sunshine rate of change is positive number, then judge whether the ratio of described current changing rate and described intensity of sunshine rate of change is less than the first predetermined threshold value, if so, then judge that the ratio of described current changing rate and described intensity of sunshine rate of change is in predetermined threshold value interval; If the ratio of described current changing rate and described intensity of sunshine rate of change is negative, then judge whether the ratio of described current changing rate and described intensity of sunshine rate of change is greater than the second predetermined threshold value, if so, then judge that the ratio of described current changing rate and described intensity of sunshine rate of change is in predetermined threshold value interval; Wherein said first predetermined threshold value is positive number, and described second predetermined threshold value is negative.

6. the working state monitoring system of a solar photovoltaic power plant, described solar photovoltaic power plant comprises at least one solar-energy photo-voltaic cell array, described solar-energy photo-voltaic cell array comprises multiple solar cell string and has the header box of multiple input and an output, the input of each described header box is connected with the output of a solar cell string or upper level header box, it is characterized in that, described system comprises:

7. the working state monitoring system of solar photovoltaic power plant according to claim 6, it is characterized in that, also comprise classification alarm module, for after determining that the operating state of solar cell string or the upper level header box be connected with described input is abnormal, send corresponding alarm signal according to described abnormal class.

8. the working state monitoring system of solar photovoltaic power plant according to claim 7, is characterized in that, described classification alarm module comprises:

9. the working state monitoring system of solar photovoltaic power plant according to claim 1, is characterized in that, described first judge module comprises: