Low-voltage flexible direct-current interconnection system applied to centralized transformer area of power grid

Abstract

The invention discloses a low-voltage flexible direct-current interconnection system applied to a centralized transformer area of a power grid, which belongs to the technical field of flexible direct-current power transmission and comprises a centralized transformer area structure module, a transformer area flexible interconnection cabinet module and a communication module. The centralized transformer area structure module is used for pulling alternating-current lines in each transformer area to a container or a transformer area flexible interconnection cabinet in a power distribution station room through a standby interval; the transformer area flexible interconnection cabinet module is used for converging alternating current lines of all transformer areas to form a direct current bus and realizing intelligent scheduling of power and switching control of an operation state according to an instruction issued by a power distribution main station; and the communication module is used for realizing communication between the centralized transformer area structure module and the flexible interconnection cabinet module.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible direct current power transmission, and in particular to a low-voltage flexible direct current interconnection system applied to a centralized power grid area. Background Art

[0002] As an indispensable form of energy in modern society, electric energy plays a vital role in daily life and production. With the continuous growth of electricity demand, power equipment is becoming more and more numerous and complex. How to ensure the stability of power supply to user equipment and the efficient use of power resources has become an important challenge facing the power industry.

[0003] At present, the power supply system generally uses the substation as the basic power supply unit, and each substation operates relatively independently. However, this independent operation mode has significant problems: on the one hand, due to the significant differences in the load conditions of different substations, some substations may face insufficient power due to excessive load, resulting in overheating of the power supply line, voltage fluctuations and even frequent failures, seriously affecting the normal power consumption experience of users; on the other hand, some substations fail to fully utilize their power supply capacity due to small loads, resulting in a waste of power resources. Summary of the invention

[0004] The object of the present invention is to provide a low-voltage flexible DC interconnection system for use in a centralized grid area to solve the problems raised in the above-mentioned background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] A low-voltage flexible DC interconnection system for a centralized power grid area, the system comprising a centralized power grid area structure module, a power grid area flexible interconnection cabinet module, and a communication module;

[0007] The centralized substation structural module is used to pull AC lines from each substation through the spare interval to the substation flexible interconnection cabinet module in the container or the distribution station building;

[0008] The flexible interconnection cabinet module of the substation is used to aggregate the AC lines of each substation to form a DC bus and realize intelligent power scheduling and operation status conversion control according to the instructions issued by the power distribution master station;

[0009] The communication module is used to realize the communication between the centralized table area structure module and the flexible interconnection cabinet module.

[0010] Furthermore, the centralized substation structure module includes substation 1 unit and substation 2 unit; the substation 1 unit and substation 2 unit are respectively equipped with a side converter, a main transformer low-side switch, and a distribution transformer measurement and control device.

[0011] In the above technical solution, the physical connection between the substations is realized through the centralized substation structure module, so that power resources can be flexibly allocated between different substations, providing basic conditions for subsequent power dispatching and mutual assistance.

[0012] Furthermore, the communication module includes an optical fiber communication unit and an instruction issuing unit;

[0013] The optical fiber communication unit communicates through an optical fiber channel when the distance between the flexible interconnection cabinet in the substation exceeds 100 meters;

[0014] The instruction issuing unit is used to receive the remote adjustment instruction issued by the power distribution master station and transmit it to the energy management unit for execution.

[0015] In the above technical solution, when the distance between the flexible interconnection cabinet and the substation is far, the use of optical fiber communication can ensure the reliability and high speed of data transmission, reduce signal attenuation and interference, and improve the overall communication performance of the system; by receiving the remote adjustment instructions from the distribution master station in real time and transmitting them to the energy management unit for execution, remote intelligent control is realized, and the response speed and automation level of the system are improved.

[0016] Furthermore, the flexible interconnection cabinet module of the substation includes an AC / DC bidirectional converter unit, an AC side incoming line switch unit, a DC bus unit, a DC side reserved switch unit and an energy management unit;

[0017] The AC / DC bidirectional converter unit is used to perform bidirectional conversion from AC to DC to achieve bidirectional flow of power;

[0018] The AC side incoming line switch unit is used to control the connection and disconnection of the AC line;

[0019] The DC bus unit is used to collect the DC power converted by the area 1 unit and the area 2 unit;

[0020] The DC side reserved switch unit is used for centralized access to the DC source, load and energy storage unit;

[0021] The energy management unit collects information from the distribution transformer measurement and control device and the AC / DC bidirectional converter unit through communication, and realizes remote adjustment and mutual assistance functions and operation status conversion functions according to the remote control instructions issued by the distribution master station or the power failure detected locally.

[0022] The remote adjustment mutual assistance function receives the remote adjustment command issued by the distribution master station, and adjusts the exchange power between the two substations through the transmission direction of power between the substations. The specific adjustment plan is as follows:

[0023] When the power direction is positive, it means that the active power flows from the unit in area 1 to the unit in area 2, and the unit in area 1 is dispatched to the unit in area 2 according to the active target power issued by the dispatch instruction;

[0024] When the active power direction is negative, it means that the active power flows from the unit in area 2 to the unit in area 1, then the unit in area 2 is dispatched to the unit in area 1 according to the active target power issued by the dispatch instruction;

[0025] When the reactive power direction is positive, it means that the reactive power flows from the unit in area 1 to the unit in area 2, then the unit in area 1 is dispatched to the unit in area 2 according to the reactive target power issued by the dispatch instruction;

[0026] When the reactive power direction is negative, it means that the reactive power flows from the area 2 unit to the area 1 unit. Then the area 2 unit is dispatched to the area 1 unit according to the reactive target power issued by the dispatch instruction.

[0027] In the above technical solution, by receiving the remote control instructions from the main distribution station, the power transmission direction and size between the substations are adjusted in real time, achieving precise mutual assistance of power and effectively balancing the load of each substation.

[0028] Furthermore, the operation state conversion function includes interconnection disconnection state, power mutual aid state, and area power transfer state;

[0029] The interconnection disconnection state indicates that the AC / DC bidirectional converters of the two substations are both in the shutdown state;

[0030] The power mutual assistance state means that the substation 1 supplements part of the power for the substation 2, or the substation 2 supplements part of the power for the substation 1, and the power flow direction and size are dynamically adjusted according to the remote control command;

[0031] The substation area power transfer status means that when one substation area loses power, another substation area provides power to the lost substation area when the remaining capacity meets the power demand of the lost substation area.

[0032] In the above technical scheme, unnecessary energy loss and equipment wear can be reduced by setting the interconnection disconnection state; the utilization efficiency of power resources can be improved by setting the power mutual assistance state; and the reliability and continuity of power supply can be improved by setting the substation transfer state.

[0033] Furthermore, the operation state conversion function realizes the conversion between the three states by receiving the remote adjustment mutual assistance command from the power distribution master station;

[0034] Transition from the interconnection disconnection state to the power mutual aid state: after receiving the remote adjustment mutual aid command from the distribution master station, set the converter on the side of area 1 to the "constant DC voltage control" mode and start it up, and at the same time set the converter on the side of area 2 to the "grid-connected PQ source" mode, and set the active power and reactive power target values ​​of the converter on the side of area 2 and start it up;

[0035] The power mutual assistance state is changed to the interconnection disconnection state: when the remote regulation mutual assistance command of the distribution master station is received and the active power and reactive power in the command are both 0, the active power and reactive power of the side converter of area 2 are set to 0 and shut down, and the side converter of area 1 is shut down.

[0036] Interconnection disconnection state to area transfer state: when a power outage is detected in a certain area and the remaining capacity of another area can meet the power demand of the area with power outage or after receiving the instruction from the distribution master station, the side converter working mode of the two areas is adjusted to restore the power supply of the area with power outage and enter the corresponding area transfer state;

[0037] The substation transfer state is changed to the interconnection disconnection state: when the power supply to the lost station area is restored, the side converters of the two substations are turned off and the low-voltage side switch of the main transformer in the lost station area is closed by remote control to return the two substations to the interconnection disconnection state and wait for the next dispatch order.

[0038] In the above technical solution, automatic state conversion is achieved by receiving remote control mutual assistance commands from the power distribution master station, which reduces the possibility of manual intervention and erroneous operation and improves the intelligence level and operation efficiency of the system.

[0039] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0040] The present invention realizes DC interconnection and power mutual assistance between substations through the substation flexible interconnection cabinet module, and can dynamically adjust power distribution according to the actual load conditions of each substation, effectively avoiding power supply line failures caused by excessive load, and improving the stability and reliability of power supply;

[0041] The present invention has multiple operating state conversion functions, including interconnection disconnection state, power mutual aid state and area power transfer state. The system's working mode can be flexibly adjusted according to actual conditions to meet power supply requirements in different scenarios. At the same time, an optical fiber communication unit is used for long-distance communication to ensure the rapid transmission and execution of instructions, thereby improving the system's response speed and operating efficiency.

[0042] The present invention can collect the operating status information of each substation in real time through the energy management unit and the communication module, and perform intelligent scheduling and control according to the instructions issued by the power distribution master station, so as to realize remote monitoring and automatic management of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0044] Figure 1It is a system module diagram applied to the low-voltage flexible DC interconnection system of the centralized power grid area;

[0045] Figure 2 It is an operation status transition diagram applied to the low-voltage flexible DC interconnection system in the centralized substation of the power grid. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] See also Figure 1-Figure 2 , the present invention provides a technical solution:

[0048] A low-voltage flexible DC interconnection system for a centralized power grid area, the system comprising a centralized power grid area structure module, a power grid area flexible interconnection cabinet module, and a communication module;

[0049] The centralized substation structural module is used to pull AC lines from each substation through the spare interval to the substation flexible interconnection cabinet module in the container or the distribution station building;

[0050] The substation flexible interconnection cabinet module is used to converge the AC lines of each substation to form a DC bus and realize intelligent power scheduling and operation status conversion control according to the instructions issued by the distribution master station; the communication module is used to realize communication between the centralized substation structure module and the flexible interconnection cabinet module.

[0051] The centralized substation structure module includes substation 1 unit and substation 2 unit; the substation 1 unit and substation 2 unit are respectively equipped with side converters, main transformer low-side switches, and distribution transformer measurement and control devices.

[0052] In the above technical solution, the physical connection between the substations is realized through the centralized substation structure module, so that power resources can be flexibly allocated between different substations, providing basic conditions for subsequent power dispatching and mutual assistance.

[0053] The communication module includes an optical fiber communication unit and an instruction issuing unit; when the distance between the flexible interconnection cabinet and the substation exceeds 1()() meters, the optical fiber communication unit communicates through an optical fiber channel; the instruction issuing unit is used to receive remote adjustment instructions issued by the distribution master station and pass them to the energy management unit for execution.

[0054] In the above technical solution, when the distance between the flexible interconnection cabinet and the substation is far, the use of optical fiber communication can ensure the reliability and high speed of data transmission, reduce signal attenuation and interference, and improve the overall communication performance of the system; by receiving the remote adjustment instructions from the distribution master station in real time and transmitting them to the energy management unit for execution, remote intelligent control is realized, and the response speed and automation level of the system are improved.

[0055] Furthermore, the flexible interconnection cabinet module of the substation includes an AC / DC bidirectional converter unit, an AC side incoming line switch unit, a DC bus unit, a DC side reserved switch unit and an energy management unit;

[0056] The AC / DC bidirectional converter unit is used to perform bidirectional conversion from AC to DC to achieve bidirectional flow of power;

[0057] The AC side incoming line switch unit is used to control the connection and disconnection of the AC line;

[0058] The DC bus unit is used to collect the DC power converted by the area 1 unit and the area 2 unit;

[0059] The DC side reserved switch unit is used for centralized access to the DC source, load and energy storage unit;

[0060] The energy management unit collects information from the distribution transformer measurement and control device and the AC / DC bidirectional converter unit through communication, and realizes remote adjustment and mutual assistance functions and operation status conversion functions according to the remote control instructions issued by the distribution master station or the power failure detected locally.

[0061] The remote adjustment mutual assistance function receives the remote adjustment command issued by the distribution master station, and adjusts the exchange power between the two substations through the transmission direction of power between the substations. The specific adjustment plan is as follows:

[0062] When the power direction is positive, it means that the active power flows from the unit in area 1 to the unit in area 2, and the unit in area 1 is dispatched to the unit in area 2 according to the active target power issued by the dispatch instruction;

[0063] When the active power direction is negative, it means that the active power flows from the unit in area 2 to the unit in area 1, then the unit in area 2 is dispatched to the unit in area 1 according to the active target power issued by the dispatch instruction;

[0064] When the reactive power direction is positive, it means that the reactive power flows from the unit in area 1 to the unit in area 2, then the unit in area 1 is dispatched to the unit in area 2 according to the reactive target power issued by the dispatch instruction;

[0065] When the reactive power direction is negative, it means that the reactive power flows from the area 2 unit to the area 1 unit. Then the area 2 unit is dispatched to the area 1 unit according to the reactive target power issued by the dispatch instruction.

[0066] In the above technical solution, by receiving the remote control instructions from the main distribution station, the power transmission direction and size between the substations are adjusted in real time, achieving precise mutual assistance of power and effectively balancing the load of each substation.

[0067] The operation state conversion function includes interconnection disconnection state, power mutual aid state, and area power transfer state;

[0068] The interconnection disconnection state indicates that the AC / DC bidirectional converters of the two substations are both in the shutdown state;

[0069] The power mutual assistance state means that the substation 1 supplements part of the power for the substation 2, or the substation 2 supplements part of the power for the substation 1, and the power flow direction and size are dynamically adjusted according to the remote control command;

[0070] The power transfer status of the substation area means that when one substation area loses power, the remaining capacity of another substation area meets the power demand of the lost substation area and supplies power to the lost substation area; when the power supply to the lost substation area is restored, the interconnection disconnection state is restored;

[0071] In the above technical scheme, unnecessary energy loss and equipment wear can be reduced by setting the interconnection disconnection state; the utilization efficiency of power resources can be improved by setting the power mutual assistance state; and the reliability and continuity of power supply can be improved by setting the substation transfer state.

[0072] The operation state conversion function realizes the conversion between the three states by receiving the remote adjustment and mutual assistance command from the power distribution master station;

[0073] Transition from the interconnection disconnection state to the power mutual aid state: after receiving the remote adjustment mutual aid command from the distribution master station, set the converter on the side of area 1 to the "constant DC voltage control" mode and start it up, and at the same time set the converter on the side of area 2 to the "grid-connected PQ source" mode, and set the active power and reactive power target values ​​of the converter on the side of area 2 and start it up;

[0074] The power mutual assistance state is changed to the interconnection disconnection state: when the remote regulation mutual assistance command of the distribution master station is received and the active power and reactive power in the command are both 0, the active power and reactive power of the side converter of area 2 are set to 0 and shut down, and the side converter of area 1 is shut down.

[0075] Interconnection disconnection state to area transfer state: when a power outage is detected in a certain area and the remaining capacity of another area can meet the power demand of the area with power outage or after receiving the instruction from the distribution master station, the side converter working mode of the two areas is adjusted to restore the power supply of the area with power outage and enter the corresponding area transfer state;

[0076] The substation transfer state is changed to the interconnection disconnection state: when the power supply to the lost station area is restored, the side converters of the two substations are turned off and the low-voltage side switch of the main transformer in the lost station area is closed by remote control to return the two substations to the interconnection disconnection state and wait for the next dispatch order.

[0077] In the above technical solution, automatic state conversion is achieved by receiving remote control mutual assistance commands from the power distribution master station, which reduces the possibility of manual intervention and erroneous operation and improves the intelligence level and operation efficiency of the system.

[0078] In the embodiment of the present invention, the substation area 1 and the substation area 2 pull out AC lines through their respective spare intervals, and these lines are directly connected to the AC side incoming line switch unit of the substation area flexible interconnection cabinet module, which is responsible for the power flow between the control substation area and the flexible interconnection cabinet;

[0079] Since the distance between the substation and the flexible interconnection cabinet may be far (more than 100 meters), optical fiber communication is used. The optical fiber is connected from the substation to the communication module in the flexible interconnection cabinet to realize data exchange between the energy management unit and the distribution master station and distribution transformer measurement and control device;

[0080] In the flexible interconnection cabinet module of the substation, two sets of AC / DC bidirectional converters are connected to the AC side incoming line switch in the flexible interconnection cabinet respectively, converting AC power into DC power and converging it through the DC bus. Interfaces are reserved on the DC bus for future access to DC sources, loads, and storage units, and the reserved switches on the DC side are used to control the on and off of these interfaces. The bidirectional converter receives instructions from the energy management unit to switch the operating state and adjust the power.

[0081] The energy management unit realizes data exchange with the distribution transformer measurement and control device and the AC / DC bidirectional converter through the communication module. It receives the instructions from the distribution master station and intelligently dispatches power according to the real-time data. The energy management unit receives the remote adjustment instructions issued by the distribution master station through the communication module, and adjusts the working mode and output power of the AC / DC bidirectional converter according to the power direction and target power value in the instructions. For example, if the instruction requires substation 1 to transfer power to substation 2, the energy management unit sets the converter on the substation 1 side to the "constant DC voltage control" mode and adjusts its output power; at the same time, the converter on the substation 2 side is set to the "grid-connected PQ source" mode, and its output is set according to the power value in the instruction.

[0082] Interconnection disconnection state: Both bidirectional converters are in shutdown state, and no power flows in the DC bus. At this time, there is no mutual assistance function between the two sections, and each section operates independently;

[0083] Power mutual assistance state: After receiving the remote adjustment command, the energy management unit starts the converter to enter the power mutual assistance mode; for example, when the substation 1 supplements part of the power for the substation 2, the energy management unit sets the converter on the substation 1 side to the "constant DC voltage control" mode and starts it, and sets the converter on the substation 2 side to the "grid-connected PQ source" mode and starts it after setting the power value as needed;

[0084] Substation transfer status: When the energy management unit detects that substation 2 loses power and substation 1 has residual capacity, the converter on the substation 1 side is set to the "constant DC voltage control" mode and turned on, and the converter on the substation 2 side is set to the "off-grid VF source" mode and turned on to provide temporary power supply for substation 2;

[0085] Interconnection disconnection and power mutual assistance: After receiving the remote adjustment command, start the converters on the side of area 1 and area 2 in turn, and set the corresponding operating status and power value;

[0086] Power mutual assistance interconnection disconnection: After receiving the remote adjustment command (power value is 0), first reduce the transfer power to 0, and then shut down the two side converters in turn;

[0087] Substation area power supply transfer and interconnection disconnection: When it is detected that power supply to the lost station area is restored, the two side converters are turned off first, and then the low-voltage side switch of the main transformer in the lost station area is remotely controlled to close the switch to return the two substations to the interconnection disconnection state.

[0088] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low-voltage flexible DC interconnection system for a centralized power grid area, characterized in that: The system includes a centralized area structure module, an area flexible interconnection cabinet module, and a communication module; The centralized substation structural module is used to pull AC lines from each substation through the spare interval to the substation flexible interconnection cabinet module in the container or the distribution station building; The flexible interconnection cabinet module of the substation is used to aggregate the AC lines of each substation to form a DC bus and realize intelligent power scheduling and operation status conversion control according to the instructions issued by the power distribution master station; The communication module is used to realize the communication between the centralized table area structure module and the flexible interconnection cabinet module.

2. According to claim 1, a low-voltage flexible DC interconnection system applied to a centralized power grid area is characterized in that: The centralized substation structure module includes substation 1 unit and substation 2 unit; the substation 1 unit and substation 2 unit are respectively equipped with side converters, main transformer low-side switches, and distribution transformer measurement and control devices.

3. According to claim 1, a low-voltage flexible DC interconnection system applied to a centralized power grid area is characterized in that: The flexible interconnection cabinet module of the substation area includes an AC / DC bidirectional converter unit, an AC side incoming line switch unit, a DC bus unit, a DC side reserved switch unit and an energy management unit; The AC / DC bidirectional converter unit is used to perform bidirectional conversion from AC to DC to achieve bidirectional flow of power; The AC side incoming line switch unit is used to control the connection and disconnection of the AC line; The DC bus unit is used to collect the DC power converted by the area 1 unit and the area 2 unit; The DC side reserved switch unit is used for centralized access to the DC source, load and energy storage unit; The energy management unit collects information from the distribution transformer measurement and control device and the AC / DC bidirectional converter unit through communication, and realizes remote adjustment and mutual assistance functions and operation status conversion functions according to the remote control instructions issued by the distribution master station or the power failure detected locally.

4. According to claim 1, a low-voltage flexible DC interconnection system for a centralized power grid area is characterized in that: The communication module includes an optical fiber communication unit and an instruction issuing unit; The optical fiber communication unit communicates through an optical fiber channel when the distance between the flexible interconnection cabinet in the substation exceeds 100 meters; The instruction issuing unit is used to receive the remote adjustment instruction issued by the power distribution master station and transmit it to the energy management unit for execution.

5. According to claim 3, a low-voltage flexible DC interconnection system applied to a centralized power grid area is characterized in that: The remote adjustment mutual assistance function receives the remote adjustment command issued by the distribution master station, and adjusts the exchange power between the two substations through the transmission direction of power between the substations. The specific adjustment plan is as follows: When the power direction is positive, it means that the active power flows from the unit in area 1 to the unit in area 2, and the unit in area 1 is dispatched to the unit in area 2 according to the active target power issued by the dispatch instruction; When the active power direction is negative, it means that the active power flows from the unit in area 2 to the unit in area 1, then the unit in area 2 is dispatched to the unit in area 1 according to the active target power issued by the dispatch instruction; When the reactive power direction is positive, it means that the reactive power flows from the unit in area 1 to the unit in area 2, then the unit in area 1 is dispatched to the unit in area 2 according to the reactive target power issued by the dispatch instruction; When the reactive power direction is negative, it means that the reactive power flows from the area 2 unit to the area 1 unit. Then the area 2 unit is dispatched to the area 1 unit according to the reactive target power issued by the dispatch instruction.

6. The low-voltage flexible DC interconnection system for centralized power grid areas according to claim 3 is characterized in that: The operation state conversion function includes interconnection disconnection state, power mutual aid state, and area power transfer state; The interconnection disconnection state indicates that the AC / DC bidirectional converters of the two substations are both in the shutdown state; The power mutual assistance state means that the substation 1 supplements part of the power for the substation 2, or the substation 2 supplements part of the power for the substation 1, and the power flow direction and size are dynamically adjusted according to the remote control command; The substation area power transfer status means that when one substation area loses power, another substation area provides power to the lost substation area when the remaining capacity meets the power demand of the lost substation area.

7. The low-voltage flexible DC interconnection system for centralized power grid areas according to claim 6 is characterized in that: The operation state conversion function realizes the conversion between the three states by receiving the remote adjustment and mutual assistance command from the power distribution master station; Transition from the interconnection disconnection state to the power mutual assistance state: after receiving the remote adjustment mutual assistance command from the distribution master station, set the converter on the side of area 1 to the "constant DC voltage control" mode and start it up, and at the same time set the converter on the side of area 2 to the "grid-connected PQ source" mode, and set the active power and reactive power target values ​​of the converter on the side of area 2 and start it up; The power mutual assistance state is changed to the interconnection disconnection state: when the remote regulation mutual assistance command of the distribution master station is received and the active power and reactive power in the command are both 0, the active power and reactive power of the side converter of area 2 are set to 0 and shut down, and the side converter of area 1 is shut down.

8. The low-voltage flexible DC interconnection system for centralized power grid areas according to claim 6 is characterized in that: The mutual conversion between the interconnection disconnection state and the area supply transfer state in the operation state conversion function; Interconnection disconnection state to area transfer state: when a power outage is detected in a certain area and the remaining capacity of another area can meet the power demand of the area with power outage or after receiving the instruction from the distribution master station, the side converter working mode of the two areas is adjusted to restore the power supply of the area with power outage and enter the corresponding area transfer state; The substation transfer state is changed to the interconnection disconnection state: when the power supply to the lost station area is restored, the side converters of the two substations are turned off and the low-voltage side switch of the main transformer in the lost station area is closed by remote control to return the two substations to the interconnection disconnection state and wait for the next dispatch order.

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