Transformer area islanding protection method under planned power failure, medium and terminal

Abstract

The invention is suitable for the technical field of power distribution, and relates to a transformer area island protection method under planned power outage, a medium and a terminal, and the method comprises the steps: S10, additionally installing a passive island protection device at a photovoltaic user grid-connected point, carrying out the communication with a communication gateway through a carrier wave, and achieving the conventional protection through the overvoltage / undervoltage and overvoltage / underfrequency action principles; s20, an anti-islanding protection device is installed at a low-voltage bus of the distribution transformer on the transformer area side, and the anti-islanding protection device is used for reading the turn-off state of a low-voltage main switch, has an operation locking function and communicates with the communication gateway through RS485; s30, a communication gateway is installed on the transformer area side, and communication with the power distribution information system master station is established for uploading information of the protection devices on the local side and the transformer area side; and the main station is also used for sending commands issued by the main station to realize remote control of the main station. The method is simple in process and convenient to operate, detection blind areas can be effectively eliminated, and the recognition accuracy is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electric power distribution, and in particular relates to a method, medium and terminal for protecting an island in a substation under a planned power outage. Background Art

[0002] The island state under planned power outage means that after the distributed photovoltaic power source is normally connected to the grid, when the power grid is artificially cut off, if the output of the distributed photovoltaic power source is just in a balanced state with the local load, that is, the voltage and frequency at the grid connection point do not change much, then the photovoltaic power source will continue to supply power to the surrounding loads, forming a self-sufficient independent power supply system that neither the grid company nor the photovoltaic power source can control. This phenomenon is called the island state.

[0003] At present, anti-islanding protection in distribution network substations at home and abroad mainly adopts protection that reflects voltage / frequency changes. The protection function is built into the monitoring terminal of the distributed photovoltaic power generation inverter (local side) or the grid-connected point switch (substation side). Existing anti-islanding protection measures include passive protection, active protection, disturbance impedance method and remote trip technology. When the output power of the photovoltaic system is balanced with the local load power, the passive detection method will lose the ability to detect the islanding effect and there will be a large detection blind spot. The active protection has high detection accuracy and small blind spot, but the control is more complicated and reduces the quality of the inverter output power. The disturbance impedance method requires the installation of an anti-islanding device with high reliability requirements. When the main switch is detected in the open position and the busbar has voltage, it is considered that the power grid is in an islanding state, that is, the disturbance impedance is put into operation. Mis-investment will cause a short circuit fault. The investment of this solution is large. In the future, in complex distribution substation scenarios such as low-voltage generator access, substation interconnection, flexible direct current, wind and solar storage, etc., the use of anti-islanding devices has certain limitations, there is a possibility of false operation, and the scalability is not strong. The remote trip technology requires the purchase of special signal sending and receiving equipment, which is cumbersome to install, very complicated to operate, and has a high investment cost. The signal generator installed on the grid side will interfere with other equipment installed on the power line, requiring certification and permission from relevant departments, and the approval is relatively complicated. As can be seen from the above, the existing anti-islanding protection measures have certain drawbacks. The patent with announcement number CN117317982B provides a wide-area anti-islanding protection system, which includes an anti-islanding protection host installed on the substation side, an anti-islanding protection sub-machine installed on the distributed power station side, and an anti-islanding protection communication system; the anti-islanding protection host is networked according to the voltage level, and the anti-islanding protection sub-machine communicates with the anti-islanding protection host of the upper-level substation based on a wireless network; the anti-islanding protection host of the high-voltage substation transmits an islanding remote trip signal to the anti-islanding protection host of the lower-voltage substation, and the anti-islanding protection hosts of the substations with the same voltage level do not transmit islanding remote trip signals; the anti-islanding protection sub-machine on the distributed power station side receives the islanding remote trip signal from the anti-islanding protection host of the upper-level substation. The above patent uses remote trip technology to achieve anti-islanding protection, which has the same drawbacks as the prior art.

[0004] Therefore, how to provide a method for island protection of substations under planned power outages to solve the drawbacks of existing anti-island protection measures, effectively eliminate detection blind spots, and improve recognition accuracy is an urgent problem to be solved by personnel in this technical field. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for island protection of a substation under planned power outages, so as to solve the problems of detection blind spots and low recognition accuracy in the prior art anti-island protection methods; in addition, the present invention also provides a medium and terminal for island protection of a substation under planned power outages.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for island protection in a planned power outage, comprising the following steps:

[0008] S10. Install a passive island protection device at the photovoltaic user grid connection point, communicate with the communication gateway through a carrier, and use the over / under voltage and over / under frequency action principle to achieve conventional protection;

[0009] S20. Install an anti-islanding protection device at the low-voltage busbar of the distribution transformer on the substation side. The anti-islanding protection device is used to read the off state of the low-voltage main switch, has an operation locking function, and communicates with the communication gateway through RS485;

[0010] S30, installing a communication gateway on the substation side, establishing communication with the main station of the power distribution information system, for sending information of the protection devices on the local side and the substation side; and for sending commands issued by the main station to realize remote control of the main station;

[0011] In the method:

[0012] In normal operation, planned power outage at the master station, or planned low-voltage power outage:

[0013] The local passive island protection switch, the area-side anti-island protection device, and the communication gateway are all operating normally;

[0014] When a high voltage power outage occurs:

[0015] Power outage preparation stage: the master station sends a remote blocking signal;

[0016] During the maintenance operation implementation phase: if the power supply in the substation area does not need to be guaranteed, the substation area will remain locked; if the power supply in the substation area needs to be guaranteed, the main switch of the substation area will be disconnected;

[0017] After the maintenance work is completed, the power supply is restored: the grid power is sent back to the main switch power supply side of the substation, and the distribution information system master station sends a command to the anti-islanding protection device to release the remote locking signal.

[0018] Furthermore, under normal operating conditions, the remote blocking signal and the local blocking signal of the anti-islanding protection device on the substation side and the passive islanding protection device on the local side are both 0.

[0019] Furthermore, during the preparation stage for power outage, the remote lockout signal of the anti-island protection device on the substation side is 1, and the local lockout signal is 0. When the lockout signal exists, even if the anti-island protection device identifies the island state, the disturbance impedance will not be activated; the remote lockout signal of the passive island protection device on the local side is 1, and the local lockout signal is 0. When the lockout signal exists, it will actively trip to isolate the photovoltaic power supply and disable the automatic reclosing function.

[0020] Furthermore, during the implementation phase of maintenance work, when the substation needs power supply protection measures, if the substation is connected to the power supply during a power outage, the communication gateway is powered on again after the connection. If it is identified that the main switch is in the open state, the conditions for the formation of the local locking signal are met; if the substation is connected to the power supply during a power outage, the gateway remains powered on at all times. After the main switch is disconnected, the gateway identifies that the main switch is in the open state, which also meets the conditions for the formation of the local locking signal.

[0021] Furthermore, the gateway sends the signal back to the main station, and the main station sends a local locking signal. After receiving the local locking signal, the protection device changes the remote locking signal to a local locking signal. The remote locking signal of the anti-island protection device on the substation side is 0, and the local locking signal is 1. When there is a locking signal, the disturbance impedance will not be activated even if the island state is identified; the remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 1. When there is a locking signal, it will actively trip to isolate the photovoltaic power supply and continue to disable the automatic reclosing.

[0022] Furthermore, when the maintenance work is completed and the power supply is restored, if there are no power supply guarantee measures: the remote locking signal of the anti-island protection device on the substation side is 1, and the local locking signal is 0, the remote locking signal of the passive island protection device on the local side is 1, and the local locking signal is 0, it is changed to the remote locking signal of the anti-island protection device on the substation side is 0, and the local locking signal is 0, the remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 0.

[0023] Furthermore, if there are power supply guarantee measures: the remote locking signal of the anti-island protection device on the substation side is 0, the local locking signal is 1, the remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 1, it is changed to the remote locking signal of the anti-island protection device on the substation side is 0, the local locking signal is 1, the remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 1.

[0024] Furthermore, when the power supply is exited, the anti-island protection device sends information to the main station, and the main station sends a command to the protection device to release the local locking signal. The remote locking signal of the anti-island protection device on the substation side is 0, and the local locking signal is 0. The remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 0.

[0025] In a second aspect, the present invention further provides a computer-readable storage medium, wherein the storage medium stores a computer program, and the computer program implements the above method when executed by a processor.

[0026] In a third aspect, the present invention further provides an electronic terminal, comprising: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes the method as described above.

[0027] Compared with the prior art, the island protection method, medium and terminal for a planned power outage provided by the present invention have at least the following beneficial effects:

[0028] At present, there are detection blind spots in the anti-islanding protection methods in the distribution network substations at home and abroad, and the recognition accuracy is not high. The process of the present invention is simple and easy to operate. The passive protection switch on the local side adopts the HPLC power carrier communication method to realize the function of communicating with the automation master station; the conventional anti-islanding device does not have the function of communicating with the automation master station, and can usually only play a role in the case of substation failure. The anti-islanding device on the grid side used by the present invention realizes communication with the automation master station through RS485 communication, and the possibility of misoperation can be avoided by coordinating the locking signal; the gateway is installed on the substation side to establish communication with the distribution information system master station, on the one hand, the information of the local side and substation side protection devices can be sent up, and on the other hand, the command issued by the master station can be sent down to realize remote control of the master station, and unified coordinated action is realized; the islanding protection method of the present invention realizes comprehensive protection under various planned power outages without blind spots and omissions; the present invention realizes complex access scenarios, such as power generation vehicle access, other interconnected power supply access and other power supply scenarios. The islanding protection configuration scheme. The present invention eliminates the management blind spot of low-voltage photovoltaic distributed power access and improves the recognition accuracy, which is of great significance for achieving orderly grid connection of distributed power sources and improving power supply safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the scheme of the present invention, a brief introduction is given below to the figures required for use in the description of the embodiments. Obviously, the figures described below are some embodiments of the present invention. For ordinary technicians in this field, other figures can be obtained based on these figures without paying any creative work.

[0030] Figure 1 A flow chart of a method for protecting an island in a substation under a planned power outage provided by an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of the configuration of a method for island protection in a substation under a planned power outage provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0034] The present invention provides a method for island protection of a distribution network distribution area under a planned power outage, which is applied to the anti-island protection process of a distribution network distribution area. The method for island protection of a distribution network distribution area under a planned power outage comprises the following steps:

[0035] S10. Install a passive island protection device at the photovoltaic user grid connection point, communicate with the communication gateway through a carrier, and use the over / under voltage and over / under frequency action principles to achieve conventional protection;

[0036] S20. Install an anti-islanding protection device at the low-voltage busbar of the distribution transformer on the substation side. The anti-islanding protection device is used to read the off state of the low-voltage main switch, has an operation locking function, and communicates with the communication gateway through RS485;

[0037] S30. Install a communication gateway on the substation side to establish communication with the power distribution information system master station to upload information about protection devices on the local and substation sides; and also to send commands issued by the master station to achieve remote control of the master station.

[0038] The invention has a simple process and is easy to operate, can effectively eliminate detection blind spots, and improves recognition accuracy.

[0039] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0040] The present invention provides a method for island protection of a distribution network under planned power outage, which is applied to the anti-island protection process of a distribution network distribution network. Figure 1 and Figure 2 In this embodiment, the island protection method for the station area under the planned power outage includes the following steps:

[0041] S10. Install a passive island protection device at the photovoltaic user's grid connection point, communicate with the communication gateway through a carrier (HPLC), and use the over / under voltage and over / under frequency action principle to achieve conventional protection. There is no need to change the photovoltaic inverter grid-connected switch invested by the user. After installing a passive island protection device with communication, the power supply company has the possibility to directly control the photovoltaic user's switch on and off, without relying on the user's inverter grid-connected switch;

[0042] S20. An anti-islanding protection device is installed at the low-voltage busbar of the distribution transformer on the substation side. The anti-islanding protection device is used to read the off state of the low-voltage main switch and has an operation locking function. It communicates with the communication gateway through RS485. The operating principle is that when the main switch is detected in the open position and the busbar has voltage, it is considered that the power grid is in an islanding state, and the disturbance impedance is input to break the power balance under the islanding state, so that the local side passive islanding protection device will trip when it detects voltage or frequency deviation, realizing the distributed photovoltaic grid disconnection;

[0043] S30. Install a communication gateway on the substation side to establish communication with the main station of the power distribution information system to send up information about the protection devices on the local and substation sides; it is also used to send down commands issued by the main station to achieve remote control of the main station, eliminating the current situation in which passive protection and anti-islanding devices work independently under traditional protection methods, and achieving unified coordinated action.

[0044] First, let's explain the terms. Remote blocking signal: The anti-islanding device on the substation side and the passive islanding protection device on the local side both have signal interfaces. Remote means the signal directly sent by the master station after recording the planned power outage status through the distribution network information system. After receiving the blocking signal, the anti-islanding device will not put into disturbance impedance even if it detects the islanding state; the passive islanding protection switch will trip and disable the reclosing function. Even if it detects that it meets the grid-connected state, it will not close.

[0045] Local blocking signal: a special state recognized by the anti-islanding device. When the anti-islanding device has a remote blocking signal and detects that the main switch is in the open position, the signal is sent to the master station through the gateway, and then the local blocking signal is sent to the anti-islanding device on the return area side and the passive islanding protection switch on the local side through the master station. After receiving the blocking signal, the anti-islanding device will not input the disturbance impedance even if it detects the islanding state; the passive islanding protection switch will trip and disable the reclosing function. Even if it detects that it meets the grid-connected state, it will not close.

[0046] Furthermore, in this embodiment, the protection device operates as follows during a planned power outage:

[0047] Normal operating status: The anti-islanding protection device on the substation side is operating normally, the remote locking signal is 0, and the local locking signal is 0; the passive islanding protection device on the local side is operating normally, the remote locking signal is 0, and the local locking signal is 0; the communication gateway is operating normally.

[0048] Main grid planned power outage, low voltage planned power outage: maintain normal operation.

[0049] High-voltage planned power outage: 1. During the power outage preparation stage, on the day of the planned power outage, before the power outage operation and the access to the power supply guarantee, the power distribution information system reads that the substation containing photovoltaic distributed power is not included in the 10kV power supply network transfer power supply plan to restore power supply. The master station sends a remote blocking signal. Since the power outage is not executed, the gateway is still operating normally. The remote blocking signal of the anti-islanding protection device on the grid side is 1, and the local blocking signal is 0. When there is a blocking signal, even if the anti-islanding protection device recognizes the island state, it will not put into disturbance impedance. The remote blocking signal of the passive islanding protection device on the local side is 1, and the local blocking signal is 0. When there is a blocking signal, it will actively trip, isolate the photovoltaic power supply, and disable the automatic reclosing function.

[0050] 2. During the maintenance operation implementation phase, if the substation does not need power supply protection measures, maintain the above locking state; if the substation needs power supply protection measures, such as low-voltage mobile generators, whether it is power outage access or loop access, the power supply company will disconnect the substation main switch to prevent the power supply from being sent back to the planned power outage area in the 10kV network. If the substation is connected to the power supply during a power outage, the gateway will be powered on again after access. If it is recognized that the main switch is in the open state, the conditions for the formation of the local locking signal are met; if the substation is connected to the power supply without power outage, the gateway will always remain powered on. After the main switch is disconnected (loop released), the gateway will recognize that the main switch is in the open state, which also meets the conditions for the formation of the local locking signal. The gateway sends the signal back to the master station, and the master station sends the local locking signal. After receiving the local locking signal, the protection device changes the remote locking signal to the local locking signal. The remote blocking signal of the anti-islanding protection device on the substation side is 0, and the local blocking signal is 1. When the blocking signal exists, even if the islanding state is identified, the disturbance impedance will not be put into use; the remote blocking signal of the passive islanding protection device on the local side is 0, and the local blocking signal is 1. When the blocking signal exists, it will actively trip, isolate the photovoltaic power supply, and continue to disable the automatic reclosing. (Since it has already tripped when the remote blocking signal is 1 before, it is an empty trip at this time and does not affect the result). If there are some unconventional power supply protection measures and the main switch of the substation is not disconnected, the remote blocking signal of the protection device will continue to work and will not cause the anti-islanding protection device on the grid side to malfunction.

[0051] 3. The maintenance work is completed and the power supply is restored: the 10kV power supply is restored, and the grid power is sent back to the main switch power supply side of the substation. The main station of the distribution information system sends a command to the protection device to release the remote locking signal. After the above analysis, the protection device has two different locking states.

[0052] Specifically, firstly, when there are no power supply guarantee measures, the remote lockout signal of the anti-island protection device on the substation side is 1, and the local lockout signal is 0, and the remote lockout signal of the passive island protection device on the local side is 1, and the local lockout signal is 0. It is changed to the remote lockout signal of the anti-island protection device on the substation side is 0, and the local lockout signal is 0, and the remote lockout signal of the passive island protection device on the local side is 0, and the local lockout signal is 0. This state represents that there are no local power supply guarantee measures. After the maintenance work is completed, electricity can be directly sent back to the substation by the feeder, and the protection device resumes normal operation.

[0053] Secondly, when there are power supply guarantee measures, the remote locking signal of the anti-island protection device on the substation side is 0, and the local locking signal is 1, and the remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 1. It is changed to the remote locking signal of the anti-island protection device on the grid side is 0, and the local locking signal is 1, and the remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 0. This state represents that the substation has power supply guarantee measures, the main switch is not closed, the master station sends a command to the protection device to set the remote locking signal to 0, and does not change the local locking signal. The anti-island protection device on the grid side and the passive island protection device on the local side are still in the locked state. Assuming that there is no locking signal, since the anti-island device detects the existence of bus low voltage (the voltage is provided by the guaranteed power supply) and the main switch is opened, it meets the islanding criterion of the anti-island protection device and will mistakenly input the disturbance impedance, causing network failure. The local locking signal can avoid misjudgment.

[0054] Furthermore, in this embodiment, when the guaranteed power supply is exited, the anti-island device considers that the power supply of the substation has returned to normal, and sends information to the main station. The main station sends a command to the protection device to release the local locking signal. The remote locking signal of the anti-island protection device on the substation side is 0, and the local locking signal is 0. The remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 0. This state represents that the substation has resumed normal power supply mode, and the protection device has resumed normal operation, waiting for the next abnormal event to occur.

[0055] An embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, any one of the methods in the present embodiment is implemented.

[0056] An embodiment of the present invention further provides an electronic terminal, comprising: a processor and a memory; the memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes any one of the methods in this embodiment.

[0057] The computer-readable storage medium in this embodiment can be understood by ordinary technicians in this field: all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to the computer program. The aforementioned computer program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other media that can store program codes.

[0058] The electronic terminal provided in this embodiment includes a processor, a memory, a transceiver and a communication interface. The memory and the communication interface are connected to the processor and the transceiver and complete communication with each other. The memory is used to store computer programs, the communication interface is used to communicate, and the processor and the transceiver are used to run computer programs so that the electronic terminal executes each step of the above method.

[0059] The island protection method, medium and terminal of the substation under planned power outage described in the above embodiment, compared with the prior art, there are detection blind spots in the anti-island protection method in the distribution network substation at home and abroad, and the recognition accuracy is not high. The process of the present invention is simple and easy to operate. The passive protection switch on the local side adopts the HPLC power carrier communication method to realize the function of communicating with the automation master station; the conventional anti-island device does not have the function of communicating with the automation master station, and can usually only play a role in the case of substation failure. The anti-island device on the grid side used by the present invention realizes communication with the automation master station through RS485 communication, and the possibility of misoperation can be avoided by the cooperation of the locking signal; the gateway is installed on the substation side to establish communication with the distribution information system master station, on the one hand, the information of the local side and substation side protection devices can be sent up, and on the other hand, the command issued by the master station can be sent down to realize remote control of the master station, and unified coordinated action is realized; the island protection method of the present invention realizes comprehensive protection under various planned power outages without blind spots and omissions; the present invention realizes complex access scenarios, such as power generation vehicle access, other interconnected power supply access and other power supply scenarios. The island protection configuration scheme. The present invention eliminates the management blind spot of low-voltage photovoltaic distributed power access and improves the recognition accuracy, which is of great significance for achieving orderly grid connection of distributed power sources and improving power supply safety.

[0060] Obviously, the embodiments described above are only preferred embodiments of the present invention, rather than all embodiments. The preferred embodiments of the present invention are shown in the accompanying drawings, but they do not limit the patent scope of the present invention. The present invention can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. Although the present invention has been described in detail with reference to the aforementioned embodiments, for those skilled in the art, it is still possible to modify the technical solutions recorded in the aforementioned specific embodiments, or to perform equivalent replacements for some of the technical features therein. Any equivalent structure made using the contents of the specification and drawings of the present invention, directly or indirectly used in other related technical fields, is also within the scope of patent protection of the present invention.

Claims

1. A method for protecting an island in a power distribution area under a planned power outage, characterized in that: The following steps are involved: S10. Install a passive island protection device at the photovoltaic user grid connection point, communicate with the communication gateway through a carrier, and use the over / under voltage and over / under frequency action principles to achieve conventional protection; S20. Install an anti-islanding protection device at the low-voltage busbar of the distribution transformer on the substation side. The anti-islanding protection device is used to read the off state of the low-voltage main switch, has an operation locking function, and communicates with the communication gateway through RS485; S30, installing a communication gateway on the substation side, establishing communication with the main station of the power distribution information system, for sending information of the protection devices on the local side and the substation side; and for sending commands issued by the main station to realize remote control of the main station; In the method: In normal operation, planned power outage at the master station, or planned low-voltage power outage: The local passive island protection switch, the area-side anti-island protection device, and the communication gateway are all operating normally; When a high voltage power outage occurs: Power outage preparation stage: the master station sends a remote blocking signal; During the maintenance operation implementation phase: if the power supply in the substation area does not need to be guaranteed, the substation area will remain locked; if the power supply in the substation area needs to be guaranteed, the main switch of the substation area will be disconnected; After the maintenance work is completed, the power supply is restored: the grid power is sent back to the main switch power supply side of the substation, and the distribution information system master station sends a command to the anti-islanding protection device to release the remote locking signal.

2. The method for protecting an isolated island in a planned power outage according to claim 1, characterized in that: Under normal operating conditions, the remote blocking signal and local blocking signal of the anti-islanding protection device on the substation side and the passive islanding protection device on the local side are both 0.

3. The method for protecting an isolated island in a planned power outage according to claim 2, characterized in that: In the power outage preparation stage, the remote blocking signal of the anti-islanding protection device at the substation side is 1, and the local blocking signal is 0. When the blocking signal exists, even if the anti-islanding protection device recognizes the islanding state, the disturbance impedance will not be activated; The remote blocking signal of the passive island protection device on the local side is 1, and the local blocking signal is 0. When a blocking signal exists, it will actively trip, isolate the photovoltaic power supply, and disable the automatic reclosing function.

4. The method for protecting an isolated island in a planned power outage according to claim 3, characterized in that: During the maintenance operation implementation phase, when the substation needs to take measures to ensure power supply, if the substation is powered off and connected to the power supply, the communication gateway will be powered on again after the connection. If it is identified that the main switch is in the open state, the conditions for the formation of the local locking signal are met; If the substation is connected to the guaranteed power supply without power outage, the gateway will always remain powered on. After the main switch is disconnected, the gateway will recognize that the main switch is in the open state, which also meets the conditions for the formation of the local locking signal.

5. The method for protecting an isolated island in a planned power outage according to claim 4, characterized in that: The gateway sends the signal back to the master station, which sends the local blocking signal. After receiving the local blocking signal, the protection device changes the remote blocking signal to the local blocking signal. The remote blocking signal of the anti-islanding protection device on the substation side is 0, and the local blocking signal is 1. When the blocking signal exists, even if the islanding state is identified, the disturbance impedance is not input; The remote blocking signal of the passive island protection device on the local side is 0, and the local blocking signal is 1. When the blocking signal exists, it will actively trip to isolate the photovoltaic power supply and continue to disable the automatic reclosing.

6. The method for protecting an island in a planned power outage according to claim 5, characterized in that: At the end of the maintenance work and the power supply restoration stage, if there are no power supply guarantee measures: the remote locking signal of the anti-island protection device on the substation side is 1, and the local locking signal is 0, the remote locking signal of the passive island protection device on the local side is 1, and the local locking signal is 0, it is changed to the remote locking signal of the anti-island protection device on the substation side is 0, and the local locking signal is 0, the remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 0.

7. The method for protecting an island in a planned power outage according to claim 6, characterized in that: If there are power supply guarantee measures: the remote locking signal of the anti-island protection device on the substation side is 0, the local locking signal is 1, the remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 1, it is changed to the remote locking signal of the anti-island protection device on the substation side is 0, the local locking signal is 1, the remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 1.

8. The method for protecting an island in a planned power outage according to claim 7, characterized in that: When the power supply is exited, the anti-island protection device sends information to the master station, and the master station sends a command to the protection device to release the local locking signal. The remote locking signal of the anti-island protection device on the substation side is 0, and the local locking signal is 0. The remote locking signal of the passive island protection device on the local side is 0, and the local locking signal is 0.

9. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

10. An electronic terminal, characterized in that: include: Processor and memory; The memory is used to store a computer program, and the processor is used to execute the computer program stored in the memory, so that the terminal executes the method according to any one of claims 1 to 8.

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