CN116937810A - Anti-islanding grid-connected circuit breaker - Google Patents
Anti-islanding grid-connected circuit breaker Download PDFInfo
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00032—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for
- H02J13/00036—Systems characterised by the controlled or operated power network elements or equipment, the power network elements or equipment not otherwise provided for the elements or equipment being or involving switches, relays or circuit breakers
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00001—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by the display of information or by user interaction, e.g. supervisory control and data acquisition systems [SCADA] or graphical user interfaces [GUI]
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J13/00—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
- H02J13/00002—Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network characterised by monitoring
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
- H02J2300/22—The renewable source being solar energy
- H02J2300/24—The renewable source being solar energy of photovoltaic origin
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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 application provides an anti-islanding grid-connected circuit breaker, and belongs to the technical field of circuit breakers. The circuit breaker comprises a first circuit breaker, a second circuit breaker, a mode switching unit connected with the first circuit breaker and the second circuit breaker, and a controller connected with the mode switching unit, wherein the controller comprises a first edge controller and a second edge controller, the two edge controllers respectively perform data acquisition and edge calculation of different parameters, and control signals are generated after the edge calculation is performed for a plurality of times to control the on-off state of the first circuit breaker and/or the second circuit breaker. The technical scheme of the application can improve the accuracy and timeliness of the change of the action state of the circuit breaker, thereby accurately realizing the switching of the grid-connected mode or the off-grid mode.
Description
Technical Field
The application belongs to the technical field of circuit breakers, and particularly relates to an anti-islanding grid-connected circuit breaker.
The patent application is a grid-connected circuit breaker capable of preventing island and a control method thereof, and the patent application is divided into patent application number 2022106688895.
Background
Along with the continuous expansion of the grid-connected scale of the photovoltaic new energy, the traditional radiation type single-ended network is changed into a multi-end network, and by connecting a user with a power terminal, electric power does not flow from a transformer substation to a load unidirectionally, and an island phenomenon can exist, so that a reverse power transmission phenomenon is caused. According to the specification of the technical provision of the photovoltaic power station access power system, GB/T19964-2012, 12.3.3: the photovoltaic power station is provided with an independent anti-islanding protection device, and the action time is not more than 2s. "provision of photovoltaic Power station access Power System design Specification" GB/T50866-2013, clause 6.3.2: the photovoltaic power station needs to be provided with an independent anti-islanding protection device, so that the safety of power grid faults and overhauling is ensured. Thus, when an islanding effect occurs in a photovoltaic power plant, i.e. when the grid loses voltage due to some fault cause, it should be provided with the ability to rapidly monitor the islanding and immediately disconnect the connection to the grid.
In the prior art, whether the island effect is generated is generally judged according to the collected data, and the grid-connected inverter is enabled to work in a grid-connected mode or an off-grid mode by controlling the on-off of the contactor. In the off-grid working mode, the amplitude and the frequency of the output voltage are controlled to realize full-load uninterrupted power supply. In the grid-connected working mode, the grid-connected current is sampled, feedback control is carried out on the grid-connected current, the amplitude and the phase of the output current are directly controlled, the sine of the grid-connected current is realized, better dynamic performance is obtained, the sensitivity of the output current to parameter change can be reduced, and the robustness of the system is enhanced.
However, the inventor finds that, in the prior art, after the island effect is mostly judged by collecting data once (or periodically collecting single data), whether the island phenomenon exists is judged by a preset index threshold value based on a corresponding passive island detection method or an active island detection method. The single data acquisition or the single index static judgment mode is easy to have detection dead zones, the threshold value is difficult to determine, the on-off state of the circuit breaker cannot be accurately controlled, the grid-connected mode or the off-grid mode is difficult to switch in real time, and the damage is brought to the stability of the power grid.
How to improve the accuracy and timeliness of the change of the action state of the circuit breaker, so as to accurately realize the switching of the grid-connected mode or the off-grid mode, becomes a technical problem to be further solved in the field.
Disclosure of Invention
In order to solve the technical problems, the application provides an anti-islanding grid-connected circuit breaker and a control method thereof.
In a first aspect of the application, an anti-islanding grid-tie circuit breaker is presented, the circuit breaker comprising a first circuit breaker and a second circuit breaker.
The first circuit breaker is connected to a public power grid;
the second circuit breaker is connected with the photovoltaic micro-grid;
the first circuit breaker and the second circuit breaker are connected to a controller through a mode switching unit;
the controller acquires the electric energy state parameters of the public power grid and the photovoltaic micro-grid, generates a control signal and sends the control signal to the mode switching unit;
the mode switching unit changes the on-off state of the first circuit breaker and/or the second circuit breaker based on the control signal so as to realize the switching of the grid-connected mode or the off-grid mode.
It can be seen that as a first advantage of the present application, the circuit breaker of the present application comprises a first circuit breaker and a second circuit breaker, connected to the public grid and the photovoltaic micro-grid, respectively. Unlike available technology, which adopts one breaker, the present application adopts two breakers to detect island phenomenon and control on the public power network and the photovoltaic micro power network.
More specifically, as a further improvement, the controller includes a first edge controller;
the first edge controller performs current edge calculation after acquiring a first electric energy state parameter of the public power grid and the first circuit breaker connection end in a current acquisition period to obtain a first current edge calculation result;
generating a first control signal based on the first current edge calculation result and a first previous edge calculation result, wherein the first control signal is used for controlling the on-off of the first circuit breaker;
and the first previous edge result is obtained by performing edge calculation after the first edge controller acquires the second electric energy state parameters of the public power grid and the first circuit breaker connection end in the previous acquisition period of the current acquisition period.
As yet another refinement, the controller includes a second edge controller;
the second edge controller performs second edge calculation after acquiring a third electric energy state parameter of the connecting end of the photovoltaic micro-grid and the second circuit breaker in the current acquisition period to obtain a second current edge calculation result;
generating a second control signal based on the second current edge calculation result and a second previous edge calculation result, wherein the second control signal is used for controlling the on-off of the second circuit breaker;
and the second previous edge result is obtained by performing edge calculation after the second edge controller acquires a fourth electric energy state parameter of the connection end of the photovoltaic micro-grid and the second circuit breaker in the previous acquisition period of the current acquisition period.
Obviously, as a second advantage of the present application, each edge calculation of the present application is determined by combining the previous calculation result, rather than determining only according to a single data acquisition result or determining only a single index as in the prior art; meanwhile, the data types based on each calculation are different, so that the monitoring blind area can be avoided.
As another implementation manner of the foregoing first aspect, the first edge controller obtains an electrical energy state parameter a of a connection end of the public power grid and the first circuit breaker, and then performs first edge calculation to obtain a first edge calculation result;
the second edge controller obtains the electric energy state parameter B of the connection end of the photovoltaic micro-grid and the second circuit breaker and then executes second edge calculation to obtain a second edge calculation result;
the control signal is generated based on the first edge calculation result and the second edge calculation result.
In the above technical solution, the electrical energy state parameter a and the electrical energy state parameter B include one of a voltage/frequency trend value, a voltage phase jump value, and a voltage harmonic detection value;
the first edge controller acquires different electric energy state parameters A each time to execute the first edge calculation;
the second edge controller acquires different electric energy state parameters B each time to execute the second edge calculation;
the power state parameter A and the second power state parameter B are different.
Based on the setting of the acquisition period, the controller further comprises a timer; the timer is used for setting the acquisition period.
In a second aspect of the present application, a control method of an anti-islanding grid-connected circuit breaker is provided, the intelligent energy grid-connected circuit breaker includes a first circuit breaker and a second circuit breaker, the first circuit breaker and the second circuit breaker are connected to a controller through a mode switching unit, and the controller includes a first edge controller and a second edge controller.
Based on the above architecture, the method comprises the following steps:
s710: the first edge controller acquires a first electric energy state parameter of the public power grid and the first circuit breaker connection end in a current acquisition period, and then executes current edge calculation to obtain a first current edge calculation result;
s720: generating a first control signal based on the first current edge calculation result and a first previous edge calculation result, wherein the first control signal is used for controlling the on-off of the first circuit breaker;
the first previous edge result is obtained by performing edge calculation after the first edge controller acquires the electric energy state parameters of the public power grid and the first breaker connection end in the previous acquisition period of the current acquisition period;
s740: the second edge controller acquires a third electric energy state parameter of the connecting end of the photovoltaic micro-grid and the second circuit breaker in the current acquisition period, and then executes second edge calculation to obtain a second current edge calculation result;
s750: generating a second control signal based on the second current edge calculation result and a second previous edge calculation result, wherein the second control signal is used for controlling the on-off of the second circuit breaker;
the second previous edge result is obtained by performing edge calculation after the second edge controller acquires the electric energy state parameters of the photovoltaic micro-grid and the connection end of the second circuit breaker in the previous acquisition period of the current acquisition period.
S760: calculating the consistency of the first control signal and the second control signal in the current acquisition period;
if the consistency is greater than a preset value, the acquisition period is increased;
otherwise, reducing the acquisition period;
s770: returning to step S710.
In the further embodiment, the method of carrying out island phenomenon judgment by single static acquisition data in the prior art is further avoided, dynamic adjustment of the acquisition period is carried out, the method is more in line with actual conditions, the suitability of the adjustment period is improved, and the accuracy and timeliness of the change of the action state of the circuit breaker are improved.
In a third aspect of the present application, based on the intelligent energy grid-connected breaker of the first aspect, a control method of the intelligent energy grid-connected breaker is provided as follows:
s910: the first edge controller acquires the electric energy state parameter A of the public power grid and the first breaker connecting end, and then executes first edge calculation to obtain a first edge calculation result;
s920: the second edge controller acquires the electric energy state parameter B of the connection end of the photovoltaic micro-grid and the second circuit breaker, and then executes second edge calculation to obtain a second edge calculation result;
s930: generating a control signal based on the first edge calculation result and the second edge calculation result;
s940: and changing the on-off states of the first circuit breaker and the second circuit breaker based on the control signal so as to realize the switching of a grid-connected mode or an off-grid mode.
The first edge controller acquires the electric energy state parameter A in the current acquisition period to execute the first edge calculation, and acquires the electric energy state parameter C in the previous acquisition period to execute the first edge calculation;
the second edge controller acquires the electric energy state parameter B in the current acquisition period to execute the second edge calculation, and acquires the electric energy state parameter D in the previous acquisition period to execute the second edge calculation.
The A-B-C-D represents different electric energy state parameters, and shows that in the technical scheme of the application, not only are the electric energy state parameters collected by each edge controller calculated each time different, but also the electric energy state parameters collected by different edge controllers in the same collecting period are different, so that the blind area or the repeatability of the monitoring data is further avoided.
In general, the technical scheme of the application has at least the following beneficial effects:
(1) The circuit breaker comprises a first circuit breaker and a second circuit breaker which are respectively connected to a public power grid and a photovoltaic micro-grid. Different from the mode that one breaker is adopted in the prior art, the application adopts the mode of two breakers, and island phenomenon detection and on-off control can be respectively executed on the public power grid and the photovoltaic micro-grid side;
(2) Each edge calculation is determined by combining the previous calculation result, and is not determined according to a single data acquisition result or a single index as in the prior art; meanwhile, the data types based on each calculation are different, so that monitoring blind areas can be avoided;
(3) Not only are the electric energy state parameters collected by each edge controller calculated each time different, but also the electric energy state parameters collected by different edge controllers in the same collection period are also different, so that the blind area or the repeatability of the monitoring data is further avoided.
Further advantages of the application will be further elaborated in the description section of the embodiments in connection with the drawings.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic main structure of an anti-islanding grid-connected circuit breaker according to an embodiment of the application;
FIG. 2 is a schematic diagram of a further preferred embodiment of an anti-islanding grid tie breaker according to an embodiment of the present application;
FIG. 3 is a flow chart of an embodiment of a method of controlling an anti-islanding grid tie breaker in accordance with an embodiment of the present application;
fig. 4 is a flowchart of an embodiment of a method for controlling an anti-islanding grid-connected circuit breaker according to another embodiment of the application.
Detailed Description
The application will be further described with reference to the drawings and detailed description.
Fig. 1 is a schematic main structure of an anti-islanding grid-connected circuit breaker according to an embodiment of the application.
In fig. 1, the circuit breaker comprises a first circuit breaker and a second circuit breaker, the first circuit breaker being connected to a public power grid; the second circuit breaker is connected with the photovoltaic micro-grid; the first circuit breaker and the second circuit breaker are connected to a controller through a mode switching unit; the controller acquires the electric energy state parameters of the public power grid and the photovoltaic micro-grid, generates a control signal and sends the control signal to the mode switching unit; the mode switching unit changes the on-off state of the first circuit breaker and/or the second circuit breaker based on the control signal so as to realize the switching of the grid-connected mode or the off-grid mode.
As a more specific embodiment, the utility grid is a three-phase four-wire utility grid, and the first circuit breaker and the second circuit breaker may be air circuit breakers.
It will be appreciated that anti-islanding protection is an important protection for photovoltaic power plants as a general standard requirement. When the power grid has high voltage, low voltage, high frequency and low frequency faults, the photovoltaic grid-connected circuit breaker trips in time. And when the power grid is recovered to supply power and the voltage and the frequency reach the allowable values, the grid-connected circuit breaker is required to be automatically switched on.
Meanwhile, in general requirements (for example, a 0.4 kV-10 kV voltage class distributed photovoltaic power station), only the inverter is required to have the capability of rapidly monitoring an island and immediately disconnecting the island from a power grid. However, for photovoltaic power plants of voltage class 35kV and above, the above protection standard cannot be achieved by only the inverter, and at this time, an intelligent island protection device should be additionally configured. This is also one of the application scenarios proposed by the technical solution of the present application.
The relevant prior art can be found in the following documents, which are incorporated as part of the embodiments of the present application for an understanding of the relevant principles:
[1] xu Yanhua the anti-islanding protection is applied in photovoltaic power stations [ J ]. Shihe technology, 2021 (4): 2.
[2] Cheng Qiming, wang Yingfei, cheng Yinman, et al, review of island detection methods in distributed generation grid-tie systems [ J ]. Power System protection and control, 2011,39 (6): 8.
Based on the parameters, the controller collects the electric energy state parameters of the public power grid and the photovoltaic micro power grid, then performs edge calculation, generates a control signal and sends the control signal to the mode switching unit;
the control signal comprises opening or closing the first breaker or the second breaker;
the mode switching unit changes the on-off state of the first circuit breaker and/or the second circuit breaker based on the control signal so as to realize the switching of the grid-connected mode or the off-grid mode.
In particular, the controller collects the electric energy state parameters of the public power grid and the photovoltaic micro-grid, then performs edge calculation, judges whether island effect exists on the public power grid and/or the photovoltaic micro-grid side, thereby controlling the on-off state of the first circuit breaker and/or the second circuit breaker,
in this embodiment, the circuit breaker comprises a first circuit breaker and a second circuit breaker, connected to the public grid and the photovoltaic micro-grid, respectively. Unlike the prior art, which mostly adopts a circuit breaker, the embodiment adopts two circuit breakers, and can respectively execute island phenomenon detection and on-off control on the public power grid and the photovoltaic micro-grid side.
It will be appreciated that the islanding detection has a related maturation algorithm in the art, for example, see the cited documents, and in this embodiment, no further description is necessary.
The embodiment shown in fig. 1 adopts two circuit breakers, and can perform island phenomenon detection on the public power grid and the photovoltaic micro-grid side respectively, but cannot avoid the error caused by the monitoring blind area or the static monitoring index.
For this purpose, reference is continued to fig. 2. Fig. 2 is a schematic structural diagram of a further preferred embodiment of an anti-islanding grid-tie breaker according to an embodiment of the application.
In fig. 2, the controller includes a first edge controller and a second edge controller.
The first edge controller is connected to the public power grid and the first breaker connecting end and is used for acquiring electric energy state parameters of the public power grid and the first breaker connecting end;
and the second edge controller is connected to the connection end of the photovoltaic micro-grid and the second circuit breaker and is used for acquiring the electric energy state parameters of the connection end of the photovoltaic micro-grid and the second circuit breaker.
As a specific example, the electric energy state parameter includes one of a voltage/frequency trend value, a voltage phase jump value, and a voltage harmonic detection value.
It should be noted that in various embodiments of the present application, each acquisition of a power state parameter is performed continuously during a certain acquisition period, and thus is a continuous value and trend value analysis process.
Specifically, the voltage/frequency trend value, that is, the statistical value of the voltage or frequency in the acquisition period, includes one of average value, maximum value, minimum value and variance;
the voltage phase abrupt change value is obtained by collecting the change of the voltage transformation phase difference at the common point of the detection current and the common point, and when the change value is larger than a set threshold value, the voltage phase abrupt change value is considered to be detected;
the voltage harmonic detection value is the value of the Total Harmonic Distortion (THD) of the voltage monitored in the acquisition period.
Thus, as a specific example, the power state parameters collected by embodiments of the present application include at least 4 types: voltage trend value, frequency trend value, voltage phase jump value, voltage harmonic detection value.
Based on these power state parameters, it can be determined whether the island phenomenon exists, and the related principles or algorithms can be referred to in the prior art, which will not be described herein, because the improvement of the embodiments is not in improving the related principles or algorithms themselves.
The following further describes modifications of the various embodiments of the present application in conjunction with fig. 2.
In a first embodiment, the first edge controller performs current edge calculation after acquiring a first electric energy state parameter of a connection end of the public power grid and the first circuit breaker in a current acquisition period, so as to obtain a first current edge calculation result;
generating a first control signal based on the first current edge calculation result and a first previous edge calculation result, wherein the first control signal is used for controlling the on-off of the first circuit breaker;
and the first previous edge result is obtained by performing edge calculation after the first edge controller acquires the second electric energy state parameters of the public power grid and the first circuit breaker connection end in the previous acquisition period of the current acquisition period.
Correspondingly, the second edge controller performs second edge calculation after acquiring a third electric energy state parameter of the connecting end of the photovoltaic micro-grid and the second circuit breaker in the current acquisition period to obtain a second current edge calculation result;
generating a second control signal based on the second current edge calculation result and a second previous edge calculation result, wherein the second control signal is used for controlling the on-off of the second circuit breaker;
and the second previous edge result is obtained by performing edge calculation after the second edge controller acquires a fourth electric energy state parameter of the connection end of the photovoltaic micro-grid and the second circuit breaker in the previous acquisition period of the current acquisition period.
It can be understood that the first edge controller and the second edge controller are both controllers with local edge computing capability, and the edge computation specifically performed by the first edge controller and the second edge controller is to determine whether an island phenomenon exists based on the collected electric energy state parameters.
That is, the first edge controller and the second edge controller are respectively configured with related algorithms and models for judging whether the island phenomenon exists or not based on different electric energy state parameters, so that corresponding judgment can be locally executed without support of a cloud or a remote database.
Specifically, based on the first current edge calculation result and the first previous edge calculation result, a first control signal is generated, where the first control signal is used to control on-off of the first circuit breaker, and may be:
if the first current edge calculation result is the same as the first previous edge calculation result (for example, the judgment results are all island phenomenon or island phenomenon does not exist), executing the first current edge calculation result;
otherwise, the first current edge calculation result is not executed, and the acquisition period is reduced.
Specifically, based on the second current edge calculation result and the second previous edge calculation result, a second control signal is generated, where the second control signal is used to control on-off of the second circuit breaker, and may be:
if the second current edge calculation result is the same as the second previous edge calculation result (for example, the judgment results are all island phenomenon or island phenomenon does not exist), executing the second current edge calculation result;
otherwise, the second current edge calculation result is not executed, and the acquisition period is reduced.
It can be seen that each edge calculation in this embodiment is determined by combining the previous calculation result, rather than determining only according to a single data acquisition result or determining only a single index as in the prior art; meanwhile, the data types based on each calculation are different, so that the monitoring blind area can be avoided.
Correspondingly, the controller also comprises a timer; the timer is used for setting or updating the acquisition period.
In a second embodiment, the controller includes a first edge controller and a second edge controller; the first edge controller acquires the electric energy state parameter A of the connection end of the public power grid and the first circuit breaker and then executes first edge calculation to obtain a first edge calculation result; the second edge controller obtains the electric energy state parameter B of the connection end of the photovoltaic micro-grid and the second circuit breaker and then executes second edge calculation to obtain a second edge calculation result; the control signal is generated based on the first edge calculation result and the second edge calculation result.
Specifically, generating the control signal based on the first edge calculation result and the second edge calculation result includes:
if the first edge calculation result and the second edge calculation result are the same (for example, the judgment results are all island phenomena or no island phenomena), the generated control signal simultaneously opens the first circuit breaker and the second circuit breaker (if the judgment results are all island phenomena), or simultaneously closes the first circuit breaker and the second circuit breaker (if the judgment results are all island phenomena);
otherwise, the generated control signal turns off the first circuit breaker and the second circuit breaker successively.
The specific implementation mode of the disconnection is as follows:
(1) The first edge calculation result shows that island phenomenon exists, and the second edge calculation result shows that island phenomenon does not exist, and then the first circuit breaker is disconnected and then the second circuit breaker is disconnected;
(2) And if the island phenomenon exists in the first edge calculation result, the second edge calculation result shows that the island phenomenon exists, and then the second circuit breaker is disconnected firstly and then the first circuit breaker is disconnected.
In the above embodiment, the first edge controller performs the first edge calculation each time it acquires a different power state parameter a; the second edge controller acquires different electric energy state parameters B each time to execute the second edge calculation; the power state parameter A and the second power state parameter B are different.
It can be seen that in this embodiment, not only the electric energy state parameters collected by each edge controller during each calculation are different, but also the electric energy state parameters collected by different edge controllers during the same collection period are different, so that the blind area or repeatability of the monitored data is further avoided.
As a specific improvement example, if the power state parameter acquired by a certain controller at a time is a voltage trend value, specifically, a maximum voltage value Vmax and a minimum voltage value Vmin, the island detection may be performed in combination with a monitoring blind area analysis method, and a specific detection principle may be referred to as the following documents:
[3]Ye Z,Kolwalkar A,Zhang Y,et al.Evaluation of anti-islanding schemes based on nondetection zone concept[C]//IEEE Power Electronics Specialist Conference.IEEE,2004.
[4] wang Qi, shijie, su Zhidong, etc. distributed photovoltaic power plant grid-connected anti-reverse power transmission measures research [ J ]. Technological innovation and application, 2021,11 (27): 7.
How other types of power state parameters are specifically detected may be found in other prior art, and this is not described in the present disclosure.
See fig. 3-4 based on the structure of fig. 1-2.
Fig. 3 is a flowchart of an embodiment of a method for controlling an anti-islanding grid-connected circuit breaker according to an embodiment of the application.
In fig. 3, there is shown a control method of an anti-islanding grid-connected circuit breaker, the intelligent energy grid-connected circuit breaker including a first circuit breaker and a second circuit breaker, the first circuit breaker and the second circuit breaker being connected to a controller through a mode switching unit, the controller including a first edge controller and a second edge controller. The method comprises the following steps:
s710: the first edge controller acquires a first electric energy state parameter of the public power grid and the first circuit breaker connection end in a current acquisition period, and then executes current edge calculation to obtain a first current edge calculation result;
s720: generating a first control signal based on the first current edge calculation result and a first previous edge calculation result, wherein the first control signal is used for controlling the on-off of the first circuit breaker;
s740: the second edge controller acquires a third electric energy state parameter of the connecting end of the photovoltaic micro-grid and the second circuit breaker in the current acquisition period, and then executes second edge calculation to obtain a second current edge calculation result;
s750: generating a second control signal based on the second current edge calculation result and a second previous edge calculation result, wherein the second control signal is used for controlling the on-off of the second circuit breaker;
s760: calculating a consistency value R of the first control signal and the second control signal in the current acquisition period;
if the consistency value R is larger than a preset value, the acquisition period is increased;
otherwise, reducing the acquisition period;
s770: returning to step S710.
It can be seen that in the embodiment of fig. 3, the steps S710-S720 and steps S730-S740 are performed in parallel, i.e. in the same acquisition cycle;
thus, the step S770 may be actually: returning to step S710 and step S730.
It is clear that this embodiment has all the advantages of the embodiments described in the previous figures 1-2, in which the functions associated with the previous first and second embodiments are also present, and are not described in detail here.
At the same time, a further advantage of this embodiment is that the acquisition period is dynamically updated so that the data acquisition frequency more closely matches the actual operating conditions of the current grid.
In the method, the first previous edge result is obtained by performing edge calculation after the first edge controller acquires the electric energy state parameters of the public power grid and the first circuit breaker connection end in the previous acquisition period of the current acquisition period;
and the second previous edge result is obtained by performing edge calculation after the second edge controller acquires the electric energy state parameters of the photovoltaic micro-grid and the connection end of the second circuit breaker in the previous acquisition period of the current acquisition period.
Fig. 4 is a flowchart of an embodiment of a control method of an anti-islanding grid-connected circuit breaker according to another embodiment of the application, and fig. 4 is implemented based on the architecture described in fig. 2, the method including:
s910: the first edge controller acquires the electric energy state parameter A of the public power grid and the first breaker connecting end, and then executes first edge calculation to obtain a first edge calculation result;
s920: the second edge controller acquires the electric energy state parameter B of the connection end of the photovoltaic micro-grid and the second circuit breaker, and then executes second edge calculation to obtain a second edge calculation result;
s930: generating a control signal based on the first edge calculation result and the second edge calculation result;
s940: and changing the on-off states of the first circuit breaker and the second circuit breaker based on the control signal so as to realize the switching of a grid-connected mode or an off-grid mode.
The first edge controller acquires the electric energy state parameter A in the current acquisition period to execute the first edge calculation, and acquires the electric energy state parameter C in the previous acquisition period to execute the first edge calculation;
the second edge controller acquires the electric energy state parameter B in the current acquisition period to execute the second edge calculation, and acquires the electric energy state parameter D in the previous acquisition period to execute the second edge calculation.
The A-B-C-D represents different electric energy state parameters, and shows that in the technical scheme of the application, not only are the electric energy state parameters collected by each edge controller calculated each time different, but also the electric energy state parameters collected by different edge controllers in the same collecting period are different, so that the blind area or the repeatability of the monitoring data is further avoided.
In view of the above embodiments, it can be seen that the technical solution of the present application is based on different embodiments, and the technical effects thereof are gradually improved layer by layer:
a first layer: by adopting the two circuit breakers, island phenomenon detection and on-off control can be respectively carried out on the public power grid side and the photovoltaic micro-grid side;
a second layer: each edge calculation is determined by combining the previous calculation result, and is not determined according to the single data acquisition result or the single index as in the prior art; meanwhile, the data types based on each calculation are different, so that monitoring blind areas can be avoided;
third layer: not only are the electric energy state parameters acquired by each edge controller different in each calculation, but also the electric energy state parameters acquired by different edge controllers in the same acquisition period are also different, so that the blind area or the repeatability of monitoring data are further avoided;
fourth layer: and dynamically updating the acquisition period to enable the data acquisition frequency to be more in line with the actual running condition of the current power grid.
However, it should be noted that, the present application may solve a plurality of technical problems or achieve different levels of technical effects, but it is not required that each embodiment of the present application solves all technical problems or achieves all technical effects, and a certain embodiment that separately solves one or several technical problems and obtains one or more improved effects also constitutes a separate technical solution.
Furthermore, structures, or modules or units not specifically recited in the present application are consistent with the explanation of the prior art. References in the background of the application or in the detailed description section (e.g., the foregoing references [1] - [4 ]) are all considered to be part of the disclosure of this document.
Claims (4)
1. An anti-islanding grid-connected circuit breaker, the circuit breaker comprising a first circuit breaker and a second circuit breaker, characterized in that:
the device further comprises a mode switching unit connected with the first circuit breaker and the second circuit breaker and a controller connected with the mode switching unit; the controller comprises a first edge controller and a first edge controller; the controller inputs the collected electric energy state parameters of the public power grid and the photovoltaic micro-grid into a first edge controller and generates control signals after the first edge controller, and the control signals are sent to the mode switching unit; the mode switching unit changes the on-off state of the first circuit breaker and/or the second circuit breaker based on the control signal so as to realize the switching of a grid-connected mode or an off-grid mode; the first circuit breaker is connected to a public power grid; the second circuit breaker is connected with the photovoltaic micro-grid;
the first edge controller acquires a first electric energy state parameter of the connecting end of the public power grid and the first circuit breaker in a current acquisition period, and then executes first edge calculation to obtain a first current edge calculation result; generating a first control signal based on the first current edge calculation result and a first previous edge calculation result, wherein the first control signal is used for controlling the on-off of the first circuit breaker; the first previous edge calculation result is obtained by the first edge controller executing first edge calculation after acquiring the second electric energy state parameters of the public power grid and the first circuit breaker connection end in the previous acquisition period of the current acquisition period;
the second edge controller performs second edge calculation after acquiring a third electric energy state parameter of the connecting end of the photovoltaic micro-grid and the second circuit breaker in the current acquisition period to obtain a second current edge calculation result; generating a second control signal based on the second current edge calculation result and a second previous edge calculation result, wherein the second control signal is used for controlling the on-off of the second circuit breaker; the second previous edge calculation result is obtained by the second edge controller performing a second edge calculation after acquiring a fourth electric energy state parameter of the connection end of the photovoltaic micro-grid and the second circuit breaker in a previous acquisition period of the current acquisition period;
calculating the consistency of the first control signal and the second control signal in the current acquisition period; if the consistency is greater than a preset value, the acquisition period is increased; otherwise, reducing the acquisition period;
if the first current edge calculation result is the same as the first previous edge calculation result, executing the first current edge calculation result; otherwise, the first current edge calculation result is not executed, and the acquisition period is reduced; if the second current edge calculation result is the same as the second previous edge calculation result, executing the second current edge calculation result; otherwise, the second current edge calculation result is not executed, and the acquisition period is reduced; the first electric energy state parameter, the second electric energy state parameter, the third electric energy state parameter and the fourth electric energy state parameter are one of a voltage average value, a frequency average value, a voltage phase jump value and a voltage harmonic detection value, and the first electric energy state parameter, the second electric energy state parameter, the third electric energy state parameter and the fourth electric energy state parameter are different; the first edge controller acquires different electric energy state parameters each time to execute first edge calculation; the second edge controller acquires different electric energy state parameters each time to execute second edge calculation; the first edge controller and the second edge controller are different in electric energy state parameters acquired by each calculation, and the first edge controller and the second edge controller are different in electric energy state parameters acquired in the same acquisition period.
2. The anti-islanding grid tie breaker of claim 1, wherein:
the controller also includes a timer; the timer is used for setting the acquisition period.
3. The anti-islanding grid tie breaker of claim 1, wherein:
the first edge controller acquires a first electric energy state parameter of the public power grid and the first breaker connecting end, and then executes first edge calculation to obtain a first edge calculation result;
a second edge controller obtains a second electric energy state parameter of the connection end of the photovoltaic micro-grid and the second circuit breaker, and then performs second edge calculation to obtain a second edge calculation result;
and generating a control signal based on the first edge calculation result and the second edge calculation result.
4. An anti-islanding grid tie breaker as claimed in claim 3, wherein:
the first edge controller acquires a first electric energy state parameter in a current acquisition period to execute the first edge calculation, and acquires a third electric energy state parameter in a previous acquisition period to execute the first edge calculation; the second edge controller acquires a second electric energy state parameter in the current acquisition period to execute the second edge calculation, and acquires a fourth electric energy state parameter in the previous acquisition period to execute the second edge calculation.
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| CN202310914613.5A CN116937810A (en) | 2022-06-14 | 2022-06-14 | Anti-islanding grid-connected circuit breaker |
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| CN103066621B (en) * | 2012-12-25 | 2014-10-08 | 合肥工业大学 | Static switch and control method applied to connection of microgrid and public supply network |
| CN103245865B (en) * | 2013-05-27 | 2015-06-03 | 武汉大学 | Random sequence-dependent photovoltaic island state detection method and device |
| CN109245161A (en) * | 2018-10-18 | 2019-01-18 | 北京凯华网联新能源技术有限公司 | Photovoltaic for base station is from grid-connected integrated inverter power supply control system and method |
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| CN114069717B (en) * | 2022-01-18 | 2022-04-08 | 国网上海能源互联网研究院有限公司 | Method and device for anti-islanding control of transformer area integrated with distributed photovoltaic |
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