CN110380446A - A kind of power grid disconnection detection method of photovoltaic combining inverter - Google Patents
A kind of power grid disconnection detection method of photovoltaic combining inverter Download PDFInfo
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- CN110380446A CN110380446A CN201910629231.1A CN201910629231A CN110380446A CN 110380446 A CN110380446 A CN 110380446A CN 201910629231 A CN201910629231 A CN 201910629231A CN 110380446 A CN110380446 A CN 110380446A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/50—Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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Abstract
The invention discloses a kind of power grid disconnection detection methods of photovoltaic combining inverter, can effectively be responded when outlet side voltage is lost suddenly, protection equipment and personnel safety.The power grid disconnection detection method includes the following steps: to obtain BUS voltage, network voltage, output electric current and given reference current；The virtual value in 1/4 period and the virtual value of 1/2 period output electric current are calculated according to output electric current and given reference current；Judge whether network voltage is greater than the difference of BUS voltage and an allowance, when result, which is, is, if the virtual value in 1/4 period is greater than first boundary value and the virtual value of 1/2 period output electric current is less than the second boundary value, Cnt+=2；If the virtual value in 1/4 period is less than first boundary value, Cnt++；Judge whether Cnt is greater than Num3, when result, which is, is, then illustrates that power grid is abnormal.
Description
Technical field
The invention belongs to photovoltaic combining inverter fields, are related to a kind of power grid disconnection detection side of photovoltaic combining inverter
Method, especially a kind of photovoltaic combining inverter with extraneous transformer quickly detect the software approach of power grid disconnection.
Background technique
Photovoltaic inverter system is mainly the process of an energy conversion transmitting, that is, physical quantity is converted into electricity
Process.When equipment is normally grid-connected, it is transmitted energy on power grid, and steady-state operation is substantially belonged between transmitting.If
In environment operational process with voltage transformer system, certain situations occur causes power grid to be lost suddenly, and it is rapid to will lead to BUS voltage
So lifting, when next bat export electric current will suddenly abruptly increase and cause trigger overcurrent protection so that there is magnetic in transformer
Saturated phenomenon, energy flow backward to input side, may directly result in inverter and be smashed.
Just because of above-mentioned reason, need by certain methods can fast and accurately responsive electricity grid it is abnormal suddenly, thus
Protecting equipment is not in problem.
Summary of the invention
In order to solve the above-mentioned technical problem, mesh of the invention is to provide a kind of power grid disconnection detection of photovoltaic combining inverter
Method can effectively be responded when outlet side voltage is lost suddenly, protection equipment and personnel safety.
In order to achieve the above objectives, the technical solution adopted by the present invention are as follows:
A kind of power grid disconnection detection method of photovoltaic combining inverter, the power grid disconnection detection method include following step
It is rapid:
Obtain BUS voltage, network voltage, output electric current and given reference current；
The virtual value in 1/4 period and having for 1/2 period output electric current are calculated according to output electric current and given reference current
Valid value；
Judge whether network voltage is greater than the difference of BUS voltage and an allowance, when result, which is, is,
If the virtual value in 1/4 period is greater than first boundary value and the virtual value of 1/2 period output electric current is less than
The second boundary value, then Cnt+=2；If the virtual value in 1/4 period is less than first boundary value, Cnt++；
Judge whether Cnt is greater than Num3, when result, which is, is, then illustrates that power grid is abnormal；
Wherein, Cnt indicates that counting is cumulative, and final to add up and compare with Num3, Num3 is the value depending on the response time.
In a preferred embodiment, the power grid disconnection detection method in turn includes the following steps:
S1, BUS voltage, network voltage and output electric current are obtained；
S2, given reference current is obtained；
S3, the virtual value and 1/2 period output electric current for calculating for 1/4 period by the reference current and the output electric current
Virtual value；
S4, judge whether network voltage is greater than the difference of BUS voltage and an allowance；
If result be it is yes, then follow the steps S5-1, step S5-2；
If S5-1, judging that the virtual value in 1/4 period is greater than first boundary value, and 1/2 period exports electric current
Virtual value is less than the second boundary value, then Cnt+=2；
If S5-2, judging that the virtual value in 1/4 period is less than first boundary value, Cnt++；
Whether the Cnt after S5-3, judgment step S5-1 or step S5-2 is greater than Num3, if result be it is yes, illustrate power grid
It is abnormal.
It is highly preferred that if the determination result is YES, then Cnt=0, power grid disconnect, trigger protection, knot in the step S5-3
Beam detection.
It is highly preferred that in the step S4, if judging result be it is no, then follow the steps S6: judging whether Cnt is greater than 0, if
As a result it is yes, then Cnt--, terminates detection.
Preferably, if network voltage is less than the difference of BUS voltage and the allowance, Cnt-- terminates detection.
Preferably, the allowance is 10~20V.
Specifically, the first boundary value and the second boundary value are the boundary value obtained by FUZZY ALGORITHMS FOR CONTROL.
Specifically, the Num3 and response time are directly proportional.
Specifically, the given reference current is by PI control ringIt is calculated,
Wherein, t indicates integration time constant, and u (t) indicates output quantity, and Kp indicates that proportionality coefficient, e (t) indicate input quantity.
Specifically, the BUS voltage, network voltage and output electric current are calculated with peripheral sample circuit.
The present invention uses above scheme, has the advantages that compared with prior art
It is transported when the outlet side voltage of photovoltaic combining inverter is lost suddenly, such as in the environment with voltage transformer system
Occur certain situations during row power grid caused to be lost suddenly, can fast and accurately responsive electricity grid it is abnormal suddenly, to protect
Equipment is not in problem, protection staff safety.
Detailed description of the invention
It, below will be to attached drawing needed in embodiment description in order to illustrate more clearly of technical solution of the present invention
It is briefly described, it should be apparent that, drawings in the following description are only some embodiments of the invention, general for this field
For logical technical staff, without creative efforts, it is also possible to obtain other drawings based on these drawings.
Fig. 1 is a kind of flow chart of power grid disconnection detection method of embodiment.
Specific embodiment
The preferred embodiments of the present invention will be described in detail with reference to the accompanying drawing, so that advantages and features of the invention energy
It is easier to be understood by the person skilled in the art.It should be noted that the explanation for these embodiments is used to help
Understand the present invention, but and does not constitute a limitation of the invention.In addition, involved in the various embodiments of the present invention described below
And to technical characteristic can be combined with each other as long as they do not conflict with each other.
The present embodiment provides a kind of power grid disconnection detection method of photovoltaic combining inverter, the photovoltaics of especially external transformation
Inverter system.The power grid disconnection detection method includes following detecting step:
1, BUS voltage, network voltage V are calculated by the periphery MCU sample circuitgrid, export electric current I.
2, pass through PI control ringCalculate given reference current Iref。
3, pass through Iref, the virtual value I in I 1/4 period of calculatingref-rmsWith the virtual value I of 1/2 period output electric current Irms.Have
Valid value calculation formula isIt is exactly I that wherein N, which took for 1/4 period,ref-rms, taking for 1/2 period is exactly Irms。
4, judgment method 1: if Vgrid> BUS voltage-Vdelta(VdeltaIt is an allowance, generally takes 10-20V), 1/4 week
The virtual value I of phaseref-rmsThe virtual value I of > Num1 and 1/2 period output electric current Irms< Num2, Cnt+=2.
5, judgment method 2: if Vgrid> BUS voltage-Vdelta(VdeltaIt is an allowance, generally takes 10-20V) and 1/4 week
The virtual value I of phaseref-rms< Num1, Cnt++.
If 6, Vgrid< BUS voltage-Vdelta, Cnt--.
If 7, Cnt > Num3, illustrate that power grid is abnormal, trigger protection.
Wherein, the boundary value that Num1 and Num2 is obtained by FUZZY ALGORITHMS FOR CONTROL, Num3 depend primarily on the response time,
Num3 is smaller, accordingly faster.
As shown in Figure 1, above-mentioned power grid disconnection detection method specifically comprises the following steps:
S1, acquisition BUS voltage, network voltage V are calculated by the periphery MCU sample circuitgridAnd output electric current I；
S2, the reference current I for obtaining and giving is calculated by PI control ringref；
S3, pass through the reference current IrefThe virtual value I in 1/4 period is calculated with the output electric current Iref-rmsWith 1/2 week
The virtual value I of phase output electric currentrms
S4, judge network voltage VgridWhether BUS voltage-V is greater thandelta；
If result be it is yes, execute following judgements；
If S5-1, the virtual value I for judging 1/4 periodref-rms> Num1, and 1/2 period output electric current is effective
Value Irms< Num2, then Cnt+=2；
If S5-2, the virtual value I for judging 1/4 periodref-rms< Num1, then Cnt++；
Whether the Cnt after S5-3, judgment step S5-1 or step S5-2 is greater than Num3, if result be it is yes, illustrate power grid
It is abnormal, power grid disconnects, trigger protection, terminates detection.
In the step S4, if judging result be it is no, then follow the steps S6: judging whether Cnt is greater than 0, if result be it is yes,
Then Cnt-- terminates detection.In judgment step S5-1, S5-2, S5-3 and S6, if meeting Rule of judgment, will add up Cnt, finally
Cnt can and Num3 compare, if judging result be it is no, that is, be unsatisfactory for judgement adjusting, would not act, Cnt does not add up.
The above embodiments merely illustrate the technical concept and features of the present invention, is a kind of preferred embodiment, and purpose exists
It cans understand the content of the present invention and implement it accordingly in person skilled in the art, protection of the invention can not be limited with this
Range.Equivalent transformation or modification made by all Spirit Essences according to the present invention, should all cover protection scope of the present invention it
It is interior.
Claims (10)
1. a kind of power grid disconnection detection method of photovoltaic combining inverter, which is characterized in that the power grid disconnection detection method packet
Include following steps:
Obtain BUS voltage, network voltage, output electric current and given reference current；
The virtual value in 1/4 period and the virtual value of 1/2 period output electric current are calculated according to output electric current and given reference current；
Judge whether network voltage is greater than the difference of BUS voltage and an allowance, when result, which is, is,
If the virtual value in 1/4 period is greater than first boundary value and 1/2 period exports the virtual value of electric current less than second
Boundary value, then Cnt+=2；If the virtual value in 1/4 period is less than first boundary value, Cnt++；
Judge whether Cnt is greater than Num3, when result, which is, is, then illustrates that power grid is abnormal；
Wherein, Cnt indicates to count cumulative, and Num3 is the value depending on the response time.
2. power grid disconnection detection method according to claim 1, which is characterized in that the power grid disconnection detection method is successively
Include the following steps:
S1, BUS voltage, network voltage and output electric current are obtained；
S2, given reference current is obtained；
S3, the virtual value in 1/4 period and having for 1/2 period output electric current are calculated by the reference current and the output electric current
Valid value；
S4, judge whether network voltage is greater than the difference of BUS voltage and an allowance；
If result be it is yes, execute following judgements；
If S5-1, judging that the virtual value in 1/4 period is greater than first boundary value, and 1/2 period output electric current is effective
Value is less than the second boundary value, then Cnt+=2；
If S5-2, judging that the virtual value in 1/4 period is less than first boundary value, Cnt++；
Whether the Cnt after S5-3, judgment step S5-1 or step S5-2 is greater than Num3, if result be it is yes, illustrate power grid
It is abnormal.
3. power grid disconnection detection method according to claim 2, which is characterized in that in the step S5-3, if judgement knot
Fruit is yes, then Cnt=0, and power grid disconnects, and trigger protection terminates detection.
4. power grid disconnection detection method according to claim 2, which is characterized in that in the step S4, if judging result
Be it is no, then follow the steps S6: judging whether Cnt is greater than 0, if result is yes, Cnt--, terminate detection.
5. power grid disconnection detection method according to claim 1, which is characterized in that if network voltage be less than BUS voltage and
The difference of the allowance, then Cnt--, terminates detection.
6. power grid disconnection detection method according to claim 1 or 2, which is characterized in that the allowance is 10~20V.
7. power grid disconnection detection method according to claim 1 or 2, which is characterized in that the first boundary value and described
The second boundary value is the boundary value obtained by FUZZY ALGORITHMS FOR CONTROL.
8. power grid disconnection detection method according to claim 1 or 2, which is characterized in that the Num3 and response time at
Direct ratio.
9. power grid disconnection detection method according to claim 1 or 2, which is characterized in that the given reference current by
PI control ringIt is calculated, wherein t indicates integration time constant, and u (t) indicates defeated
Output, Kp indicate that proportionality coefficient, e (t) indicate input quantity.
10. power grid disconnection detection method according to claim 1 or 2, which is characterized in that the BUS voltage, network voltage
And output electric current is calculated with peripheral sample circuit.
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Cited By (1)
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