Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
In order to explain the technical means of the present invention, the following description will be given by way of specific examples.
Fig. 1 shows a schematic structural diagram of a distributed power supply island state identification system provided by an embodiment of the present invention. Referring to fig. 1, the distributed power supply island state identification system provided in this embodiment is deployed in a station area including a distributed power supply, and the system may include a convergence terminal 110, a station area main switch 121, and an intelligent device.
Specifically, the distributed power source includes photovoltaics 141 to 144, and the smart device includes 130 to 139. Optionally, the smart device 130, the smart device 131, the smart device 134, and the smart device 135 are photovoltaic inverter switches, and the smart device 132, the smart device 133, the smart device 136, the smart device 137, the smart device 138, and the smart device 139 are load meters.
The converged terminal 110 is configured to execute the distributed power supply island operation state identification method provided by the embodiment of the present invention.
In some embodiments, the bay master switch 121 is used to send a switch trip type to the convergence terminal.
In some embodiments, each intelligent device is used for sending device power failure information to the convergence terminal when power fails.
Referring to fig. 1, the distributed power supply island state identification system provided by the embodiment of the invention may further include a branch switch. Specifically, the branch switches include 122 to 129, and the branch switches are switches in the zone distribution box and the branch box except for the zone main switch.
In some embodiments, each branch switch is used to send switch outage information to the convergence terminal 110 upon a power outage.
In some embodiments, the main zone switch 121, the branch switches, and the smart devices in the zone are all communicatively connected to the convergence terminal 110.
Optionally, the station area is divided into a distribution box 161, a first branch box 162, a second branch box 163, a first island operation area 164, a second island operation area 165, and a common operation area 166.
The distribution box comprises a main distribution room switch 121, a branch switch 122 and a branch switch 123. The first branch box 162 includes a branch switch 124, a branch switch 125, and a branch switch 126. The second branch box 163 includes a branch switch 127, a branch switch 128, and a branch switch 129.
The first islanding zone 164 is an islanding zone downstream of the branch switch 122, the branch switch 124, and the branch switch 125; the second islanding zone 165 is an islanding zone downstream of the branch switch 123, the branch switch 127 and the branch switch 128.
Since the normal operation area 166 does not include any distributed power supply, the normal operation area 166 is not an island operation area, and the normal operation area 166 does not need to be determined in the island operation state identification.
It should be noted that fig. 1 only shows a structure directly related to the distributed power supply island operation state identification system in the platform area, and other structures are omitted.
Fig. 2 shows a schematic implementation flow diagram of a distributed power supply island operation state identification method provided by an embodiment of the present invention. The method is described by way of example, but not by way of limitation, as applied to a convergence terminal. Referring to fig. 2, the method may include steps S101 to S102.
S101: and receiving the switch tripping type sent by the main zone switch of the zone.
S102: and if the switch tripping type is short-circuit fault protection tripping, determining that the island operation exists in the transformer area when the first preset condition is not met.
The first preset condition is that within a first preset time after the tripping of the main switch of the transformer area, the equipment power failure information of at least one intelligent device of each island operation area in the transformer area is received. The platform area comprises at least one island operation area. The island operation area is an operation area which contains distributed power supplies under the same branch switch in the transformer area.
In some embodiments, the method further comprises step 103.
103: and when the first preset condition is established, determining that the island operation does not exist in the platform area.
Referring to fig. 1, in some embodiments, a fault occurs at F2 inside the bay, where both the external main power supply and the photovoltaic generate short circuit current at the point of fault. At this time, the main zone switch 121 short-circuit protection trips and transmits the switch trip type to the convergence terminal 110.
After receiving the switch trip type of the short-circuit protection trip, the convergence terminal 110 determines whether a first preset condition is satisfied, and if the first preset condition is not satisfied, it is determined that island operation exists in the distribution room. And if the first preset condition is satisfied, determining that no island operation exists in the transformer area.
In this embodiment, the first preset condition is that, within a first preset duration after the block main switch 121 is tripped, the equipment outage information of the at least one intelligent device in the first island operation zone 164 is received, and the equipment outage information of the at least one intelligent device in the second island operation zone 165 is received.
In some embodiments, the first preset time period is longer than the offline action time of the downstream photovoltaic inverter, and the first preset time period is longer than the action setting time of an anti-islanding protection switch connected with the photovoltaic inverter.
Taking the first island operation zone 164 as an example, under the condition that the anti-island protection switch in the first operation zone 164 works normally, if the main switch 121 of the transformer substation is tripped through short-circuit protection, the anti-island protection switch in the island operation zone 164 operates within a first preset time period. If the anti-islanding protection switch is operated, at least one of the intelligent devices 130 to 133 will have a power failure, and send device power failure information to the convergence terminal 110. The second island operation zone 165 operates in the same manner as the first island operation zone.
If the integration terminal 110 receives the equipment power failure information of at least one piece of intelligent equipment in the first island operation zone 164 and receives the equipment power failure information of at least one piece of intelligent equipment in the second island operation zone 165 within the first preset time after the short-circuit protection tripping of the main switch 121 of the transformer substation occurs, it indicates that the anti-island protection switches in the two island operation zones are both in normal operation, and the transformer substation does not have the island operation condition.
If the integration terminal 110 does not receive the equipment power failure information of any intelligent equipment in a certain island operation area within the first preset time after the short-circuit protection tripping of the main switch 121 of the transformer area, it indicates that the anti-island protection switch in the island operation area is not in normal operation, that is, is in an island operation state.
In some embodiments, the block master switch 121 communicates with the convergence terminal 110 via an RS485 connection line. The smart device communicates with the zone convergence terminal 110 through a broadband power line carrier (HPLC).
In some embodiments, the intelligent switch in the intelligent device has a coupling transmission function, that is, after the switch is opened, the HPLC signal can be transmitted through the coupling branch of the circuit breaker.
In an embodiment of the present invention, after S101, the method further includes: steps S104 to S105.
S104: and if the switch tripping type is reverse island protection tripping, determining that island operation exists in the transformer area when a second preset condition is met.
S105: and if the switch tripping type is anti-islanding protection tripping, determining that islanding operation does not exist in the transformer area when the second preset condition is not met.
The second preset condition is that the inlet voltage before the tripping of the platform main switch is greater than a preset voltage threshold.
Referring to fig. 1, when a fault occurs at F1 outside the platform, the main platform switch 121 detects a sudden change in the voltage frequency, and performs an anti-islanding protection trip after detecting a third preset time after the sudden change. The main transformer substation switch 121 sends the switch trip type of the anti-islanding protection trip to the convergence terminal 110.
After receiving the switch trip type of anti-islanding protection trip, the convergence terminal 110 determines whether a second preset condition is satisfied, thereby determining whether islanding operation exists in the transformer area.
In this embodiment, the third preset time period is longer than the offline operation time of the downstream photovoltaic inverter, and the first preset time period is longer than the operation setting time of the anti-islanding protection switch connected to the photovoltaic inverter.
Specifically, under the condition that the anti-islanding protection switches in the first islanding operation zone 164 and the second islanding operation zone 165 can work normally, the anti-islanding protection device stops outputting the distributed power supply in the islanding operation zone within a third preset time period when a fault occurs at F1, that is, before the tripping of the anti-islanding protection is performed on the main switch 121 in the transformer substation zone, the inlet voltage of the anti-islanding protection device is reduced to be below a preset voltage threshold, and no islanding operation exists in the transformer substation zone.
On the contrary, if the anti-islanding protection switches in the first islanding operation zone 164 and the second islanding operation zone 165 have a fault, and the distributed power supply cannot stop outputting after the fault occurs at F1, before the station main switch 121 performs the anti-islanding protection trip, the distributed power supply still outputs outwards, the inlet voltage of the station main switch 121 is greater than the preset voltage threshold, and the station has an islanding operation.
In one embodiment of the present invention, the determining the second preset condition may include one or two of two ways.
The first method is as follows: receiving an inlet voltage state identifier sent by a main switch of a transformer substation, wherein the inlet voltage state identifier comprises a first state value and a second state value, the first state value represents that the inlet voltage of the main switch of the transformer substation before tripping is greater than the preset voltage threshold, and the second state value represents that the inlet voltage of the main switch of the transformer substation before tripping is less than or equal to the preset voltage threshold. And when the received inlet voltage state identifier is a first state value, determining that the second preset condition is satisfied.
The second method comprises the following steps: and receiving the inlet voltage of the main transformer area switch before tripping, which is sent by the main transformer area switch after tripping. And comparing the inlet voltage with the preset voltage threshold value. And when the inlet voltage is greater than the preset voltage threshold, determining that the second preset condition is satisfied.
Optionally, the preset voltage is preset to be eighty percent of the rated voltage.
In an embodiment of the present invention, the method further includes: and step S106.
S106: under the condition that the switch tripping type sent by the main switch of the transformer area is not received, if the switch power failure information of at least one branch switch is received, when a third preset condition is not met, determining that island operation exists in the transformer area; and when the third preset condition is met, determining that no island operation exists in the platform area.
And the third preset condition is that within a second preset time after the switch power failure information is received, for each branch switch which sends the switch power failure information, equipment power failure information of at least one intelligent device is received in an island operation area at the downstream of the branch switch.
In this embodiment, the second preset time period is longer than the offline operation time of the downstream photovoltaic inverter, and the first preset time period is longer than the operation setting time of the anti-islanding protection switch connected to the photovoltaic inverter.
Referring to fig. 1, the islanding zone downstream of the branch switch 122, the branch switch 124, and the branch switch 125 is a first islanding zone 164; the island operation zone downstream of the branch switch 123, the branch switch 127 and the branch switch 128 is a second island operation zone 165. The no-operation zone downstream of branch switch 126 and the operation zone downstream of branch switch 129 is the normal operation zone 166.
When there is a fault inside the block, the block main switch 121 is not tripped, that is, the convergence terminal 110 does not receive the switch trip type sent by the block main switch 121, if the branch switch 127 is tripped, the branch switch 127 sends switch power failure information to the convergence terminal 110.
If the anti-islanding protection switch in the second islanding operation zone 165 is normal, the anti-islanding protection switch is activated within a second preset time period after the branch switch 127 is tripped. When the anti-islanding protection switch is operated, at least one of the intelligent devices 134 to 137 will have a power failure, and the powered-off intelligent device will send device power failure information to the convergence terminal 110. At the moment, the third preset condition is met, and island operation does not exist in the transformer area.
If the anti-islanding protection switch in the second islanding operation zone 165 is abnormal, the anti-islanding protection switch cannot normally operate within the second preset duration after the adjustment of the branch switch 127, and none of the intelligent devices 134 to 137 sends the device power failure information to the convergence terminal 110. At this time, the third preset condition is not established, and island operation exists in the transformer area.
On the other hand, since the distributed power supply is not included in the normal operation area 166, it is not necessary to determine the operation state of the smart device in the normal operation area 166.
The distributed power supply island operation state identification method provided by the embodiment of the invention can be used for identifying the distributed power supply island operation state on the basis of broadband power line carrier communication, power distribution internet of things communication technology and a power failure reporting mechanism on the premise of long and wide distribution lines of a low-voltage distribution network, accords with the actual operation condition of a transformer area, and is easy to implement. Because the switch trip type, the switch power failure information and the equipment power failure information can be acquired in real time, the method provided by the embodiment of the invention can quickly and effectively judge whether the island operation state of the distributed power supply exists in the transformer area when the transformer area has internal and external faults on the premise of not adding a special acquisition terminal, and uploads the island operation state of the transformer area to the main station through the fusion terminal, thereby providing guarantee for the management and safe operation of the distributed power supply.
Fig. 3 shows a flowchart of another implementation of a distributed power supply island operation state identification method provided by an embodiment of the present invention. Referring to fig. 3, in a specific embodiment, an anti-islanding protection trip state G is defined, where when the main switch of the station area is an anti-islanding protection trip, G is equal to 1, and otherwise G is equal to 0. And defining the voltage state before the tripping of the platform area main switch as Y, wherein when the voltage before the tripping of the platform area main switch is more than eighty percent of the rated voltage, Y is 1, and otherwise, Y is 0. And defining a station main switch short-circuit protection state D, and when the station main switch short-circuit protection trips, setting D to 1, otherwise, setting D to 0.
When the outside of the transformer area is in fault, the transformer area main switch detects that the voltage and the frequency are suddenly changed, after the time delay of a second preset time length, the transformer area main switch trips, and the anti-islanding protection tripping state G of the fusion terminal and the voltage state Y before the transformer area main switch trips are conducted. And if G is equal to 1 and Y is equal to 1, judging that island operation exists in the transformer area. And if G is 1 and Y is 0, judging that no island operation exists in the transformer area.
When a fault occurs inside the transformer area, the short-circuit protection of the main switch of the transformer area is tripped, and D is equal to 1. And if each island operation area reports power failure to the fusion terminal within a first preset time after the short-circuit protection tripping of the main switch of the transformer area, judging that no island operation exists in the transformer area. And if the island operation area without power failure reported to the fusion terminal exists within the first preset time after the short-circuit protection tripping of the main switch of the transformer area, judging that the island operation exists in the transformer area.
When a fault occurs in the transformer area, the main switch of the transformer area is not tripped, but the fusion terminal receives the switch power failure information reported by a branch switch. And in a third preset time after the power failure of the branch switch, if the power failure is reported by an island operation area at the downstream of the branch switch, judging that no island operation exists in the transformer area. And if the island operation zone at the downstream of the branch switch does not report power failure within a third preset time after the power failure of the branch switch, judging that island operation exists in the station zone.
It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
Fig. 4 is a schematic structural diagram of a distributed power supply island operation state identification device according to an embodiment of the present invention, and referring to fig. 4, the distributed power supply island operation state identification device 40 may include a switch trip type receiving module 410 and a first island operation determining module 420.
In some embodiments, the switch trip type reception module 410 is configured to receive a switch trip type transmitted by a main zone switch of a zone.
In some embodiments, the first islanding operation determining module 420 is configured to determine that islanding operation exists in the platform area when the first preset condition is not met if the switch trip type is a short-circuit fault protection trip.
The first preset condition is as follows: and receiving equipment power failure information of at least one intelligent device in each island operation area in the transformer area within a first preset time after the transformer area main switch is tripped. The transformer area comprises at least one island operation area, and the island operation area is an operation area containing distributed power supplies under the same branch switch.
The distributed power supply island operation state recognition device provided by the embodiment of the invention can accurately and efficiently determine whether the island operation exists in the transformer area or not, and ensure the safe operation of the transformer area where the distributed power supply is located.
In some embodiments, the first preset time period is longer than the offline action time of the downstream photovoltaic inverter and longer than the action setting time of an anti-islanding protection switch connected with the photovoltaic inverter.
In some embodiments, the device 40 for identifying an islanding operation state of a distributed generation apparatus may further include a second islanding operation determining module, configured to determine that islanding operation does not exist in the platform area when the first preset condition is met.
In some embodiments, the device for identifying an island operation state of a distributed power supply 40 may further include a third island operation determination module, configured to determine that island operation exists in the platform area when a second preset condition is met if the switch trip type is an anti-island protection trip.
The second preset condition is that the inlet voltage before the tripping of the platform main switch is greater than a preset voltage threshold.
In some embodiments, the device 40 for identifying an island operation state of a distributed power supply may further include a fourth island operation determination module, configured to determine that island operation does not exist in the transformer area when the second preset condition is not met if the switch trip type is an anti-island protection trip.
In some embodiments, the third island operation determination module is specifically configured to: and receiving an inlet voltage state identification mark sent by the main switch of the transformer area, wherein the inlet voltage state identification mark comprises a first state value and a second state value, the first state value indicates that the inlet voltage of the main switch of the transformer area before tripping is greater than a preset voltage threshold, and the second state value indicates that the inlet voltage of the main switch of the transformer area before tripping is less than or equal to the preset voltage threshold. And when the received inlet voltage state identifier is the first state value, determining that a second preset condition is satisfied.
In some embodiments, the third island operation determination module is specifically configured to: and receiving the inlet voltage of the main transformer area switch before tripping, which is sent by the main transformer area switch after tripping. And comparing the inlet voltage with a preset voltage threshold value. And when the inlet voltage is greater than the preset voltage threshold, determining that a second preset condition is satisfied.
The first preset condition is that within a first preset duration after the tripping of the main switch of the transformer area, equipment power failure information of at least one intelligent device of each island operation area in the transformer area is received. The transformer area comprises at least one island operation area, and the island operation area is an operation area for protecting the distributed power supply under the same branch switch in the transformer area.
In some embodiments, the distributed power supply island operation state identification apparatus 40 may further include a fifth island operation determination module, configured to determine that island operation exists in the platform area when a third preset condition is not met if switch power failure information of at least one branch switch is received under the condition that a switch trip type sent by the platform area main switch is not received; and when a third preset condition is met, determining that no island operation exists in the platform area.
The third preset condition is as follows: and within a second preset duration of receiving the switch power failure information, for each branch switch sending the switch power failure information, receiving equipment power failure information of at least one intelligent device in an island operation area at the downstream of the branch switch.
Fig. 5 is a schematic diagram of a convergence terminal according to an embodiment of the present invention. As shown in fig. 5, the convergence terminal 50 of this embodiment includes: a processor 500, a memory 510, and a computer program 520, such as a distributed power island operation state identification program, stored in the memory 510 and operable on the processor 500. The processor 50 executes the computer program 520 to implement the steps in each of the above embodiments of the distributed island operation state identification method, such as the steps S101 to S102 shown in fig. 2. Alternatively, the processor 500 executes the computer program 520 to implement the functions of the modules/units in the device embodiments, such as the modules 410 to 420 shown in fig. 4.
Illustratively, the computer program 520 may be partitioned into one or more modules/units that are stored in the memory 510 and executed by the processor 500 to implement the present invention. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, which are used to describe the execution process of the computer program 520 in the convergence terminal 50. For example, the computer program 520 may be divided into a switch trip type receiving module and a first island operation judging module (module in a virtual device).
The convergence terminal 50 may be a desktop computer, a notebook, a palm computer, a cloud server, or other computing devices. The convergence terminal may include, but is not limited to, a processor 500, a memory 510. Those skilled in the art will appreciate that fig. 5 is merely an example of the convergence terminal 50 and does not constitute a limitation on the convergence terminal 50 and may include more or less components than those shown, or combine certain components, or different components, for example, the convergence terminal may further include input-output devices, network access devices, buses, etc.
The Processor 500 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic, discrete hardware components, etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The storage 510 may be an internal storage unit of the convergence terminal 50, such as a hard disk or a memory of the convergence terminal 50. The memory 510 may also be an external storage device of the convergence terminal 50, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like, which are equipped on the convergence terminal 50. Further, the memory 510 may also include both an internal storage unit and an external storage device of the convergence terminal 50. The memory 510 is used for storing the computer program and other programs and data required by the convergence terminal. The memory 510 may also be used to temporarily store data that has been output or is to be output.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus/convergence terminal and method can be implemented in other ways. For example, the above-described embodiments of the apparatus/convergence terminal are merely illustrative, and for example, the division of the modules or units is only one logical function division, and there may be other division manners in actual implementation, for example, a plurality of units or components may be combined or may be integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated modules/units, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium. Based on such understanding, all or part of the flow of the method according to the embodiments of the present invention may also be implemented by a computer program, which may be stored in a computer-readable storage medium, and when the computer program is executed by a processor, the steps of the method embodiments may be implemented. . Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.