CN107395120B - Fault detection method of safety device and photovoltaic power generation system - Google Patents

Fault detection method of safety device and photovoltaic power generation system Download PDF

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CN107395120B
CN107395120B CN201710796624.2A CN201710796624A CN107395120B CN 107395120 B CN107395120 B CN 107395120B CN 201710796624 A CN201710796624 A CN 201710796624A CN 107395120 B CN107395120 B CN 107395120B
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safety device
voltage
output end
input end
meet
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CN107395120A (en
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杨宗军
邹云飞
俞雁飞
詹亮
倪华
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Sungrow Power Supply Co Ltd
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02SGENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES
    • H02S50/00Monitoring or testing of PV systems, e.g. load balancing or fault identification
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy

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  • Photovoltaic Devices (AREA)
  • Inverter Devices (AREA)
  • Emergency Alarm Devices (AREA)

Abstract

The invention provides a fault detection method of a safety device and a photovoltaic power generation system. If so, controlling the safety device to be in a turn-off state, judging whether the voltage of the input end and the voltage of the output end of the safety device meet a second preset condition, and if so, determining that the safety device is in a non-fault state. The safety device in the scheme can be self-checked, and when a fault occurs, alarm information is sent out to warn a user, so that the safety performance of the photovoltaic inverter system is improved.

Description

Fault detection method of safety device and photovoltaic power generation system
Technical Field
The invention relates to the field of photovoltaic power generation, in particular to a fault detection method of a safety device and a photovoltaic power generation system.
Background
The global photovoltaic industry and solar market is growing rapidly under the background of increasing global energy demand, high traditional energy prices, and increasing environmental concern.
Photovoltaic power generation has become a part of national energy structures, and the proportion of the photovoltaic power generation is gradually increased, but with the continuous expansion of the photovoltaic industry, the probability of accidents is also continuously increased.
Specifically, the photovoltaic arrays connected in series have very high voltage, and in order to improve the safety of the photovoltaic system, safety devices (SD, Safe device) need to be arranged in the photovoltaic power generation system, such as a fast turn-off device, a power optimizer and the like, so that the photovoltaic power generation system is turned off fast when the voltage or current exceeds the limit, the voltage between the components and the bus are reduced, and the voltage between the live conductors in a certain range is ensured not to exceed a defined safety value.
However, the inventor found that if the shutdown function fails, the component cannot be shut down, and further the safety of the human body is damaged, so that the method for detecting the failure of the safety device is provided to ensure that the safety device gives an alarm when the safety device fails, which is a great technical problem to be solved by those skilled in the art.
Disclosure of Invention
In view of this, the invention provides a method for detecting a fault of a safety device in a photovoltaic power generation system, which sends an alarm when the safety device has a fault, so as to improve the safety of the photovoltaic inverter system.
In view of this, the invention provides
A fault detection method of a safety device is applied to a photovoltaic power generation system and comprises the following steps:
acquiring a trigger instruction of self-checking of the safety device, and controlling the safety device to be in a working state;
judging whether the voltage of the input end and the voltage of the output end of the safety device meet a first preset condition, and if not, sending alarm information;
if not, controlling the safety device to be in a turn-off state, judging whether the voltage of the input end of the safety device and the voltage of the output end of the safety device meet a second preset condition, and if so, determining that the safety device is in a non-failure state.
Optionally, the method further includes:
when the input end voltage and the output end voltage of the safety device do not meet a second preset condition, controlling the safety device to start a power consumption module;
after the preset time is up, judging whether the input end voltage and the output end voltage of the safety device meet a second preset condition, if so, determining that the safety device is in a non-fault state, if not, determining that the safety device is in a fault state, and sending alarm information.
Optionally, the determining whether the voltage at the input end and the voltage at the output end of the safety device satisfy a first preset condition includes:
acquiring the voltage of an input end and the voltage of an output end of the safety device;
and judging whether the absolute value of the difference value between the voltage at the input end and the voltage at the output end is smaller than a first preset voltage value or not.
Optionally, the determining whether the voltage at the input end and the voltage at the output end of the safety device satisfy a second preset condition includes:
acquiring the voltage of an input end and the voltage of an output end of the safety device;
and judging whether the absolute value of the difference value between the voltage at the input end and the voltage at the output end is larger than a second preset voltage value or not.
Optionally, the controlling the security device to turn on the power consumption module includes:
and starting the power consumption module according to a preset frequency so as to reduce the voltage of the input end of the safety device.
A photovoltaic power generation system, comprising:
a photovoltaic module;
the input end of the safety device is connected with the output end of the photovoltaic assembly, the safety device comprises a fault detection module, the fault detection module detects the input end voltage and the output end voltage of the safety device, and when the input end voltage and the output end voltage do not meet a first preset condition, alarm information is sent;
and the inverter is connected between the output end of the safety device and a power grid.
Optionally, the method further includes:
and the communication module is connected between the fault detection module and a preset client and sends the alarm information to the client.
Optionally, the safety device is further configured to:
when the voltage of the input end and the voltage of the output end of the safety device meet a first preset condition, controlling the safety device to be in a turn-off state;
and judging whether the input end voltage and the output end voltage of the safety device meet a second preset condition, if so, determining that the safety device is in a non-fault state.
Optionally, the safety device is further configured to:
when the input end voltage and the output end voltage of the safety device do not meet a second preset condition, controlling the safety device to start a power consumption module;
after the preset time is up, judging whether the input end voltage and the output end voltage of the safety device meet a second preset condition, if so, determining that the safety device is in a non-fault state, if not, determining that the safety device is in a fault state, and sending alarm information.
According to the scheme, the invention provides the fault detection method of the safety device, which is applied to the photovoltaic power generation system. If so, controlling the safety device to be in a turn-off state, judging whether the voltage of the input end and the voltage of the output end of the safety device meet a second preset condition, and if so, determining that the safety device is in a non-fault state. The safety device in the scheme can be self-checked, and when a fault occurs, alarm information is sent out to warn a user, so that the safety performance of the photovoltaic inverter system is improved.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic flow chart of a fault detection method for a safety device according to the present invention;
FIG. 2 is a schematic flow chart of a fault detection method for a safety device according to the present invention;
FIG. 3 is a schematic flow chart of a fault detection method for a safety device according to the present invention;
FIG. 4 is a schematic flow chart illustrating a method for detecting a failure of a safety device according to the present invention;
FIG. 5 is a schematic diagram of an implementation of periodic power consumption operations according to the present invention;
fig. 6 is a schematic structural diagram of a photovoltaic power generation system provided by the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, fig. 1 is a schematic flow chart of a fault detection method for a safety device according to an embodiment of the present invention, where the fault detection method is applied to a photovoltaic power generation system, and includes the following steps:
and S11, acquiring a trigger instruction of the self-checking of the safety device, and controlling the safety device to be in a working state.
The triggering instruction of the security device may be embodied in various ways, for example, when the security device is powered on and started, the starting instruction may represent a triggering instruction of the security device for self-checking. In addition, the triggering instruction may also be triggered based on an operation of a user, for example, when the photovoltaic power generation system is in operation, a detection person manually triggers a triggering instruction of a safety device to control the safety device to perform self-detection.
In the schematic view of the above, the first embodiment of the invention,
scene one: when the safety device is powered on every time, the safety device firstly enters a self-checking mode to judge whether hardware faults exist, and at the moment, an external instruction is not needed, and the safety device is automatically executed after power is obtained.
Scene two: before the inverter starts grid connection, a self-checking instruction can be issued, the self-checking function of the safety device is started in sequence, the situation is suitable for re-grid connection of the inverter after maintenance or shutdown for other reasons, at the moment, the safety device is not powered off and restarted, but a self-checking mode can be started, and the reliability of the safety device before grid connection is ensured each time.
Generally, the security device includes two states, one is to turn off the RSD function, i.e. the security device is in normal operation, and the other is to turn on the RSD function, i.e. the security device is in off state.
S12, judging whether the voltage of the input end and the voltage of the output end of the safety device meet a first preset condition, and if not, sending alarm information.
Specifically, this embodiment provides a specific implementation step of determining whether the voltage at the input end and the voltage at the output end of the safety device satisfy a first preset condition, as shown in fig. 2, including the steps of:
s21, acquiring the voltage of the input end and the voltage of the output end of the safety device;
and S22, judging whether the absolute value of the difference value of the input end voltage and the output end voltage is smaller than a first preset voltage value.
Illustratively, after the safety device enters the self-test mode, the RSD function is first turned off, and the current output voltage Vo1 and the current input voltage Vin1 are detected to determine whether the voltage difference is less than the predetermined voltage Vth 1. Theoretically, after the RSD function is closed, the safety device is in a working state or a fixed chopping mode, the voltage difference between two sides is a known value, if the condition is not met, the device is indicated to have a fault, and warning is given.
And S13, if not, controlling the safety device to be in a turn-off state.
And S14, judging whether the input end voltage and the output end voltage of the safety device meet a second preset condition, and if so, determining that the safety device is in a non-fault state.
In this embodiment, a specific implementation step of determining whether the voltage at the input end and the voltage at the output end of the safety device satisfy a second preset condition is provided, as shown in fig. 3, including the steps of:
s31, acquiring the voltage of the input end and the voltage of the output end of the safety device;
and S32, judging whether the absolute value of the difference value of the input end voltage and the output end voltage is larger than a second preset voltage value.
Illustratively, if step S12 is satisfied, further, the safety device is controlled to enter an off state, and after a period of time delay, the output voltage Vo2 and the input voltage Vin2 are detected, and whether the difference between the two voltages is greater than Vth2 is determined; if this is the case, the hardware of the safety device is considered normal, if the condition is not met, the device cannot be considered to be faulty completely, because if the external circuit in the system clamps the output voltage of the device to a value that is just close to the input, the condition will not be met, but this does not mean that the device must be faulty.
Therefore, when the above condition is not satisfied, the power consumption of the safety device is further increased, such as opening the loop pulse, enabling the MCU and operating the peripheral, enabling the communication module, etc., and the voltage of the input-side PV module is pulled down by the load, and then it is determined whether the input-output voltage satisfies the condition, and if so, it is determined that the safety device is normal, and if not, it is determined that the safety device is faulty.
That is, on the basis of step S14, as shown in fig. 4, the method further includes the steps of:
s15, when the input end voltage and the output end voltage of the safety device do not meet a second preset condition, controlling the safety device to start a power consumption module;
and S16, after the preset time is reached, judging whether the voltage of the input end and the voltage of the output end of the safety device meet a second preset condition, if so, determining that the safety device is in a non-fault state, and if not, determining that the safety device is in a fault state, and sending alarm information.
The module for controlling the safety device to start power consumption may specifically be: and starting the power consumption module according to a preset frequency so as to reduce the voltage of the input end of the safety device.
Schematically, the present embodiment provides an implementation of a periodic power consumption operation, as shown in fig. 5, where the solid line represents the input voltage of the safety device and the dashed line represents the output voltage. The periodic change of the input voltage indicates that the device is normal if the output voltage is also periodically changed, and indicates that the device has a fault if the voltage is basically fixed.
It should be noted that the determined device fault may be a damage of a main circuit device, or a fault of a sampling circuit, or a fault of a peripheral device, a communication device, or the like, and in any case, any hardware fault may reflect that the device has a fault and there is a potential safety hazard.
To sum up, safety device in this scheme can carry out the self-checking, when breaking down, sends alarm information, gives the user in order to warn, has improved photovoltaic inverter system's security performance.
On the basis of the above embodiments, the present embodiment further provides a photovoltaic power generation system, as shown in fig. 6, including: photovoltaic module 601, safety device 602, and inverter 603.
The input end of the safety device 602 is connected to the output end of the photovoltaic module 601, the safety device includes a fault detection module (not shown in the figure), the fault detection module detects the input end voltage and the output end voltage of the safety device, and when the input end voltage and the output end voltage do not meet a first preset condition, alarm information is sent;
an inverter 603 is connected between the output of the safety device 602 and the grid 604.
Schematically, the input of safety device is connected to photovoltaic module, forms the photovoltaic group cluster after the safety device output is established ties, and the input of a plurality of group cluster parallel connection converge and insert the dc-to-ac converter. The device adopts a PLC communication mode, before the inverter is connected to the grid, a system issues a self-checking instruction, after a safety device receives the self-checking instruction, the safety device firstly closes the RSD function, at the moment, the safety device is in a working state, the input and output voltages of the safety device are detected, the voltage magnitude is compared, if the voltage difference value is out of the threshold value range, the fault of the safety device is judged, and warning is given.
If the voltage difference is within the threshold range, there may be some coincidence at this time, and further determination is required. Enabling the RSD function to enable the safety device to enter a turn-off state, detecting the difference value of the input and output voltages after a period of time delay, and judging that the safety device is normal if the voltage difference value is larger than a preset threshold value; and if the voltage difference value is smaller than the preset threshold value, controlling the safety device to increase the power consumption, such as opening a ring pulse, enabling the MCU to operate the peripheral equipment, enabling the communication module and the like. And if the voltage difference value is smaller than the preset threshold value, judging that the safety device is in a fault state and giving a warning.
In addition, the photovoltaic power generation system provided by the present embodiment further includes: and the communication module is connected between the fault detection module and a preset client and sends the alarm information to the client.
Optionally, the safety device is further configured to:
when the voltage of the input end and the voltage of the output end of the safety device meet a first preset condition, controlling the safety device to be in an opening state;
and judging whether the input end voltage and the output end voltage of the safety device meet a second preset condition, if so, determining that the safety device is in a non-fault state.
In addition to the above embodiments, the present embodiment provides a security device further configured to:
when the input end voltage and the output end voltage of the safety device do not meet a second preset condition, controlling the safety device to start a power consumption module;
after the preset time is up, judging whether the input end voltage and the output end voltage of the safety device meet a second preset condition, if so, determining that the safety device is in a non-fault state, if not, determining that the safety device is in a fault state, and sending alarm information.
In summary, the following steps: the invention provides a fault detection method of a safety device and a photovoltaic power generation system, wherein the fault detection method is applied to the photovoltaic power generation system, firstly, a trigger instruction of self-detection of the safety device is obtained to control the safety device to be in a closed state, then, whether the voltage of an input end and the voltage of an output end of the safety device meet a first preset condition is judged, and if not, alarm information is sent. If so, controlling the safety device to be in a turn-off state, judging whether the voltage of the input end and the voltage of the output end of the safety device meet a second preset condition, and if so, determining that the safety device is in a non-fault state. The safety device in the scheme can be self-checked, and when a fault occurs, alarm information is sent out to warn a user, so that the safety performance of the photovoltaic inverter system is improved.
The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (4)

1. A fault detection method of a safety device is applied to a photovoltaic power generation system and is characterized by comprising the following steps:
acquiring a trigger instruction of self-checking of the safety device, and controlling the safety device to be in a working state;
judging whether the voltage of the input end and the voltage of the output end of the safety device meet a first preset condition, and if not, sending alarm information;
if so, controlling the safety device to be in a turn-off state, judging whether the voltage of the input end of the safety device and the voltage of the output end of the safety device meet a second preset condition, and if so, determining that the safety device is in a non-fault state;
when the input end voltage and the output end voltage of the safety device do not meet the second preset condition, controlling the safety device to start a power consumption module;
after the preset time is up, judging whether the voltage of the input end of the safety device and the voltage of the output end meet a second preset condition, if so, determining that the safety device is in a non-fault state, if not, determining that the safety device is in a fault state, and sending alarm information;
wherein, the judging whether the input end voltage and the output end voltage of the safety device meet a first preset condition comprises:
acquiring the voltage of an input end and the voltage of an output end of the safety device;
judging whether the absolute value of the difference value between the voltage at the input end and the voltage at the output end is smaller than a first preset voltage value or not;
the judging whether the input end voltage and the output end voltage of the safety device meet a second preset condition comprises the following steps:
acquiring the voltage of an input end and the voltage of an output end of the safety device;
and judging whether the absolute value of the difference value between the voltage at the input end and the voltage at the output end is larger than a second preset voltage value or not.
2. The fault detection method of claim 1, wherein the controlling the safety device to turn on a power consumption module comprises:
and starting the power consumption module according to a preset frequency so as to reduce the voltage of the input end of the safety device.
3. A photovoltaic power generation system, comprising:
a photovoltaic module;
the input end of the safety device is connected with the output end of the photovoltaic assembly, the safety device comprises a fault detection module, the fault detection module detects the input end voltage and the output end voltage of the safety device, when the input end voltage and the output end voltage of the safety device meet a first preset condition, the safety device is controlled to be in a turn-off state, whether the input end voltage and the output end voltage of the safety device meet a second preset condition is judged, and if yes, the safety device is determined to be in a non-fault state; when the input end voltage and the output end voltage of the safety device do not meet a second preset condition, controlling the safety device to start a power consumption module, judging whether the input end voltage and the output end voltage of the safety device meet the second preset condition or not after preset time is up, if so, determining that the safety device is in a non-fault state, and if not, determining that the safety device is in a fault state, and sending alarm information; when the input end voltage and the output end voltage do not meet a first preset condition, sending alarm information;
and the inverter is connected between the output end of the safety device and a power grid.
4. The photovoltaic power generation system of claim 3, further comprising:
and the communication module is connected between the fault detection module and a preset client and sends the alarm information to the client.
CN201710796624.2A 2017-09-06 2017-09-06 Fault detection method of safety device and photovoltaic power generation system Active CN107395120B (en)

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CN103630832A (en) * 2012-08-27 2014-03-12 特变电工新疆新能源股份有限公司 Power-on self-detection method and device of switch piece in electric power electronic device

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Publication number Priority date Publication date Assignee Title
CN103630832A (en) * 2012-08-27 2014-03-12 特变电工新疆新能源股份有限公司 Power-on self-detection method and device of switch piece in electric power electronic device

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