Power grid fault monitoring and positioning and self-healing power restoration control method

Abstract

The invention relates to the technical field of power grid fault monitoring and automatic processing, in particular to a power grid fault monitoring and positioning and self-healing power restoration control method. A condition triggering type mechanism is adopted, three discharging types are set to achieve intelligent charging and discharging management, and the real-time performance and effectiveness of the charging and discharging work of the standby power supply are ensured through dual verification of the normal operation line and the standby line state. According to the method, the power grid fault is accurately judged by integrating multiple dimensions of switch tripping, no-current detection and total accident signals, meanwhile, a 5MW active power threshold value is set as an auxiliary criterion, misjudgment is prevented through an 8-second delay confirmation mechanism, and the fault recognition and positioning accuracy is effectively improved. According to the method, power recovery strategy generation, overload judgment and unit intertripping range function partition design are adopted, layered modeling, multi-condition collaborative judgment and sequential control strategies are combined, differentiated unit tripping and power recovery control strategies are developed, a complete safety protection mechanism is set to prevent misoperation, and intelligent self-recovery of power grid faults is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid fault monitoring and automatic processing, and in particular to a power grid fault monitoring, positioning, and self-healing and power restoration control method. Background Art

[0002] my country's existing 220kV transmission lines do exist in various forms, including single-circuit, double-circuit, and multi-circuit. These different transmission line types have distinct design and application characteristics, adapting to varying power demands and geographical environments. A single-circuit transmission line consists of a single transmission line installed on a single tower. This type of transmission line offers a simple structure and relatively low investment costs, making it suitable for areas with low power demand or relatively simple geographical conditions. A double-circuit transmission line consists of two transmission lines installed on a single tower. This type of transmission line increases transmission capacity and reduces line corridor occupancy, making it suitable for areas with high power demand or limited land resources. A multi-circuit transmission line consists of multiple transmission lines installed on a single tower. This type of transmission line further increases transmission capacity and reduces line corridor occupancy, making it suitable for areas with extremely high power demand or limited land resources. The design of double-circuit and multi-circuit transmission lines requires consideration of the interactions between lines to ensure safe and stable operation. In order to improve the fault emergency response capability, it is necessary to build a 220kV self-healing system function for single-circuit, double-circuit, and multi-circuit parallel power supply areas. When complex faults occur in single-circuit, double-circuit, and multi-circuit lines, the generator sets within the voltage loss range will be automatically cut off, and power supply to the voltage loss site will be restored through the backup power supply.

[0003] Chinese patent document CN117977578A discloses a "distribution network fault self-healing method based on intelligent distributed feeder automation." When a distribution network fault occurs, the fault type is first determined and classified into two types: single-fault point fault and multiple-fault point fault. Different self-healing strategies are then used to achieve self-healing of the distribution network fault. This solution does not consider the prerequisites for charging and discharging the backup power supply of the self-healing system, nor does it distinguish between instantaneous discharge and delayed discharge based on the actual situation of the grid fault area. Existing 220kV substations have complex wiring methods such as single-circuit, double-circuit, and multiple-circuit lines in parallel, and multiple ring networks between plants and substations. Therefore, a universal, reliable, and easy-to-maintain grid fault monitoring, location, and self-healing power restoration control method must be redesigned to solve the above problems. Summary of the Invention

[0004] Technical purpose: In order to overcome the deficiencies in the prior art, the present invention provides a power grid fault monitoring and positioning and self-healing power restoration control method to solve the problems raised in the background technology.

[0005] Technical Solution: To achieve the above objectives, the present invention discloses a method for monitoring and locating power grid faults and controlling self-healing power restoration. Based on a self-healing system model, a self-healing system instance is created to monitor and locate power grid faults in the self-healing system instance area, automatically disconnect generator sets in the faulty area, remotely close open-loop circuit breakers, and restore power through a backup power source. The method is characterized by comprising:

[0006] [S1] Charge and discharge processing: If the backup power supply of the self-healing system instance does not meet the charging conditions, it will remain in the discharge state. If the charging conditions are met, the charging will be successful after a delay. If the charging conditions are not met during the charging process, the charging will be stopped. After the charging is completed and the discharge conditions are met, the system will discharge instantly or with a delay, depending on the conditions.

[0007] [S2] Fault monitoring and location: adopts "switch tripping + switch no current + accident total signal" multi-condition comprehensive judgment;

[0008] [S2.1] When the backup power supply of the self-healing system instance is in the charging state, continuously monitor the lines in the fault monitoring area that are in normal operation. If conditions 1 and 2 are simultaneously met, a fault is determined to have occurred.

[0009] Condition 1: The switches on both sides of each circuit in all normally operating lines in the fault monitoring area are tripped, and the tripped switches have no current and the active power of the switches is lower than the commissioning set value;

[0010] Condition 2: Any circuit breaker in all normally operating lines in the fault monitoring area feeds back a total fault signal;

[0011] [S2.2] If the fault persists and lasts longer than the threshold time T T =8s, fault location is successful; record the time when the fault is first discovered T0;

[0012] [S3] Removal of units within the undervoltage range: To prevent damage to generator sets caused by asynchronous closing, the self-healing system instance removes units within the undervoltage range after the fault is successfully located. The removal queue is generated based on the monitoring points in the power plant monitoring area of ​​the self-healing system instance. The removal principle is to issue remote control commands based on the logic of serial control within the same substation and concurrent control across different substations. Whether the unit removal is successful does not affect the continued operation of the self-healing system instance.

[0013] [S4] Monitor the power restoration conditions and continuously monitor whether the power restoration conditions are met; within 300 seconds from the time T0 when the fault is first discovered in step [S2.2], if the power restoration conditions are detected to be met, execute the power restoration strategy and close the open-loop point circuit breaker; if the power restoration conditions are not detected, if the voltage in the fault area meets the conditions within 2 hours from the time T0 when the fault is first discovered in step [S2.2], close the open-loop point circuit breaker; the power restoration condition refers to the loss of voltage on all buses in the fault area;

[0014] [S5] Remote control closing open loop point circuit breaker:

[0015] If the remote control of single-circuit backup power supply or dual-circuit backup power supply is successful, then I = Detect whether the bus voltage at the fault location is restored within 100s; if any bus voltage is restored, it is determined that the self-healing power restoration is successful; otherwise, it is determined that the self-healing power restoration has failed;

[0016] A) If the remote control of the single-circuit backup power supply fails, the self-healing power restoration is deemed to have failed;

[0017] B) If the remote control of the dual-circuit backup power supply fails, the following measures shall be taken depending on the working conditions of the 1# and 2# circuits of the dual-circuit backup power supply:

[0018] B1) When the remote closing of the backup switch of circuit 1# fails, based on the power flow calculation results obtained by the advanced power system application software PAS, a remote closing command is issued if circuit 2# is not overloaded; if circuit 2# is overloaded, the self-healing system instance is discharged;

[0019] B2) When the remote closing of the 1# loop standby switch is successful and the remote closing of the 2# loop standby switch fails, determine whether the 1# loop is overloaded based on the real-time value; if it is overloaded, send a remote control command to trip the 1# loop standby switch and send an alarm signal at the same time; if the remote control tripping of the 1# loop standby switch fails, an alarm signal needs to be sent, and the dispatcher will perform subsequent operations and processing.

[0020] Furthermore, the self-healing system model includes three levels: self-healing system instance, monitoring area, and monitoring point; each self-healing system instance contains one or more monitoring areas, and each monitoring area contains one or more monitoring points; the self-healing system instance refers to a general modeling method, which is used to create one or more groups of independently modeled, non-interfering self-healing system instances, which are suitable for the operation mode of fixed faults and fixed standby lines in the power grid; the monitoring area includes a fault monitoring area, a transfer monitoring area, an overload monitoring area, and a power plant monitoring area; the fault monitoring area records the fault monitoring equipment, which is responsible for fault identification; the transfer monitoring area records the transfer monitoring equipment, which is responsible for generating power restoration strategies; the overload monitoring area records the overload monitoring equipment, which is responsible for determining overload discharge; the power plant monitoring area records the power plant monitoring equipment, which is responsible for determining the unit interlocking range; the monitoring points can add or delete monitoring equipment according to needs; the monitoring equipment includes busbars, lines, such as line switches and main transformer high-voltage switches.

[0021] Furthermore, the charging condition in step [S1] refers to simultaneously satisfying conditions 3 and 4:

[0022] Condition 3: At least one line in the fault monitoring area is operating normally;

[0023] Condition 4: At least one line in the transfer monitoring area is in standby state and has only one open-loop point. Furthermore, the discharge conditions in step [S1] include global discharge conditions and pre-fault discharge conditions;

[0024] The global discharge condition is applicable to the entire process of power grid operation and is executed when any one of conditions 5 to 11 is met. The implementation method is instantaneous discharge.

[0025] Condition 5: The self-healing system model exits, that is, the operator manually exits the self-healing system model;

[0026] Condition 6: The self-healing system instance exits, that is, the operator manually exits the self-healing system instance;

[0027] Condition 7: The lockout signal associated with the self-healing system instance is activated. Lockout signals are divided into temporary lockout and permanent lockout. After the permanent lockout signal is activated and reset, recharging is not possible even if the recharging conditions are met, and manual reset is required. After the temporary lockout signal is activated and reset, recharging is possible if the charging conditions are met.

[0028] Condition 8: Any switch or knife switch in the self-healing system instance is abnormal, and a switch or knife switch in an intermediate position appears;

[0029] Condition 9: The self-healing system instance processing times out;

[0030] Condition 10: Failed to obtain any monitoring area of ​​the self-healing system instance;

[0031] Condition 11: Self-healing system instance parameter modification: The operator modifies the parameters of a self-healing system instance through the interface;

[0032] The pre-fault discharge conditions are applicable to the case where no fault occurs. If a fault occurs, this judgment is not performed. They include:

[0033] Pre-fault discharge ①: Executed when any one of conditions 12 to 17 is met, with instantaneous discharge as the implementation method;

[0034] Condition 12: The self-healing system instance topology is abnormal;

[0035] Condition 13: The self-healing system instance has no open loop points or has multiple open loop points;

[0036] Condition 14: No line in the fault monitoring area of ​​the self-healing system instance is in normal operation;

[0037] Condition 15: The data collected from switches, circuit breakers, and busbars within the self-healing system instance modeling range is abnormal;

[0038] Condition 16: The self-healing system instance overload calculation is based on simulated power flow values ​​and the power flow diverges;

[0039] Condition 17: The self-healing system instance periodically calculates that the line power flow in the overload monitoring area exceeds the limit after power is restored;

[0040] Pre-fault discharge ②: Executed when any one of conditions 18 to 19 is met and the duration TD1 = 20s is exceeded. The implementation method is delayed discharge.

[0041] Condition 18: The self-healing system instance has no backup line;

[0042] Condition 19: The self-healing system instance operates normally and the line manual trip signal action delays discharge;

[0043] Pre-fault discharge ③: executed when condition 20 is met and the duration TD2 = 30s is exceeded, and the implementation method is delayed discharge;

[0044] Condition 20: The switch of the normally operating line in the fault monitoring area of ​​the self-healing system instance changes from the closed position to the open position for a timeout.

[0045] Furthermore, the busbar data collection anomalies described in condition 15 include: point inactivity, manual setting, invalid point value, poor communication status, exceeding reasonable limits, dead data, and collection failure.

[0046] Furthermore, the commissioning value described in condition 1 in step [S2.1] = 5MW.

[0047] Furthermore, the substations in step [S3] include: power plant substations, transmission substations, distribution substations, and converter stations.

[0048] The beneficial effects of the present invention are:

[0049] 1. The present invention provides a method for monitoring and locating power grid faults and controlling self-healing power restoration. This method uses a conditional trigger mechanism and sets three types of discharge to achieve intelligent charge and discharge management. By dual-verifying the status of normal operating lines and backup lines, it can ensure the real-time and effectiveness of the backup power supply charging and discharging work of the self-healing system instance.

[0050] 2. The present invention provides a method for monitoring and locating power grid faults and controlling self-healing power restoration. It integrates multiple dimensions, including switch tripping, no-current detection, and total accident signal, to accurately determine power grid faults. A 5MW active power threshold is set as an auxiliary criterion, and an 8-second delay confirmation mechanism is used to prevent misjudgment, effectively improving the accuracy of fault identification and location.

[0051] 3. The present invention provides a method for monitoring, locating and self-healing power restoration control of power grid faults, which adopts power restoration strategy generation, overload judgment, and functional zoning design of unit joint cutting range. By combining hierarchical modeling, multi-condition collaborative judgment, and timing control strategy, it develops differentiated unit cutting and power restoration control strategies, sets up a complete safety protection mechanism to prevent false operation, and can accurately realize intelligent self-healing of power grid faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a flow chart of a method for monitoring and locating faults in a power grid and for controlling self-healing and power restoration;

[0053] Figure 2 It is a logic sequence diagram of a power grid fault monitoring and positioning and self-healing power restoration control method;

[0054] Figure 3 The present invention is a line plant operation mode diagram of an embodiment of a power grid fault monitoring and positioning and self-healing power restoration control method. DETAILED DESCRIPTION

[0055] The following is combined with Figure 1 To the attached Figure 3 The principles and features of the present invention are described, and the examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0056] First, the terminology of the power system involved in this invention is explained as follows:

[0057] Charging state and discharging state: two operating states of the power grid, which determine the operating mode; when in the charging state, closing the switch can supply power to the grid; when in the discharging state, closing the switch cannot supply power to the grid;

[0058] Switching active power: refers to the role of the switch in controlling active power (i.e., actual power consumed); active power is the part of the power in the power system that actually does work;

[0059] Switching reactive power: refers to the role of switches in controlling reactive power (i.e., power that does not do work but participates in energy exchange). Reactive power is very important for maintaining voltage stability and improving power factor in power systems.

[0060] Commissioning value: refers to the set value of the active power compensation equipment when it is put into operation;

[0061] Switch status: divided into three states: operation, hot standby, and illegal; operation: the switch and the knife switches on both sides are in the closed position; hot standby: the switch is in the open position, and the knife switches on both sides are in the closed position; illegal: all states except operation and hot standby; the statistical table is shown in Table 1:

[0062] Table 1: Switch status statistics

[0063] state Switch position Knife switch position 1 Knife switch position 2 run combine combine combine Hot Standby point combine combine illegal point point point illegal combine point combine illegal combine combine point illegal point combine point illegal point point combine

[0064] Line status: divided into three states: normal operation, standby, and abnormal operation; normal operation: both switches on both sides are in operation; standby: one switch is in operation, the other switch is in hot standby, and the standby bus is pressurized; abnormal operation: all states except normal operation and standby; the statistical table is shown in Table 2:

[0065] Table 2: Line status statistics

[0066] state Switch 1 Switch 2 Standby bus voltage Normal operation run run -- Spare run Hot Standby Pressure Spare Hot Standby run Pressure illegal run Hot Standby No pressure illegal Hot Standby run No pressure illegal run illegal -- illegal illegal run -- illegal Hot Standby illegal -- illegal illegal Hot Standby -- illegal illegal illegal

[0067] Overload calculation: Based on the fault monitoring equipment, the inter-connected power plant, and the power transfer monitoring equipment in the model, two overload calculation methods are provided: SCADA real-time value calculation and simulated power flow calculation. The calculation results are compared with the line limit as the condition for the self-healing system's charging and discharging processing.

[0068] Simulated power flow calculation: By setting the switch position, the system simulates the power flow calculation results of three-circuit simultaneous tripping of the power grid, the complete loss of power plants within the voltage loss range, and the closing of single-circuit or double-circuit backup supply lines; the power flow under expected fault conditions is automatically calculated every minute, the results are saved, and the line is judged to be overloaded.

[0069] SCADA real-time value calculation: By calculating all current values ​​at the fault monitoring point before the fault, the expected load value of the backup line and overload monitoring area after the fault is roughly calculated, the results are saved, and the line is judged to be overloaded.

[0070] Example Fault Background and Objectives: Figure 3 As shown in the figure, the 220kV AB and AC A / B four-circuit transmission line on a single tower is a critical transmission line in Area A. According to the grid structure planned for the end of 2023 in the AD section, the 500kV AD station supplies power to the 220kV E, B, F, and C stations via the 220kV AB single-circuit and AC A / B three-circuit transmission lines on a single tower. When the 220kV AB single-circuit and AC A / B three-circuit lines trip simultaneously, the four 220kV substations lose voltage. To improve fault response capabilities, a 220kV self-healing system has been implemented in this power supply area. This system automatically disconnects generators within the voltage loss range in the event of a fault on the 220kV AB and AC A / B three-circuit transmission lines on a single tower, restoring power to the affected stations via the GH A / B lines.

[0071] Example 1 is a method for monitoring and locating power grid faults and controlling self-healing power restoration disclosed by the present invention. Figure 1 、 Figure 2 As shown, based on the self-healing system model, create AB and AC line A and B self-healing system instances;

[0072] [S1] Charge and discharge processing: If the backup power supply of the self-healing system instance does not meet the charging conditions, it will remain in the discharge state. If the charging conditions are met, the charging will be successful after a delay. If the charging conditions are not met during the charging process, the charging will be stopped. After the charging is completed and the discharge conditions are met, the system will discharge instantly or with a delay, depending on the conditions.

[0073] The AB and AC line A and B self-healing system examples simultaneously meet condition 3 (at least one line in the fault monitoring area is in normal operation) and condition 4 (at least one line in the transfer monitoring area is in standby status and has only one open-loop point), thus meeting the charging conditions and completing charging.

[0074] [S2] Fault monitoring and location: adopts "switch tripping + switch no current + accident total signal" multi-condition comprehensive judgment;

[0075] [S2.1] In the self-healing system example for lines AB and AC, the backup power supply is in the fully charged state. The fault monitoring area is continuously detecting lines in normal operation. If conditions 1 and 2 are simultaneously met, a fault is determined to have occurred, as shown in Table 3:

[0076] Table 3: Summary of fault judgment conditions;

[0077]

[0078] [S2.2] The current fault persists and lasts longer than the threshold time of 8 seconds, so the fault is located successfully; the time when the fault was first discovered, T0, is recorded;

[0079] [S3] Remove units within the undervoltage range: To prevent asynchronous closing from damaging the generator sets, the AB and AC lines A and B self-healing system instances remove units within the undervoltage range after successfully locating the fault. The removal queue is generated based on the monitoring points in the power plant monitoring area of ​​the self-healing system instance. The removal principle follows the logic of serial control within the same substation and concurrent control across different substations, issuing remote control commands. Whether the unit removal is successful does not affect the continued operation of the self-healing system instance.

[0080] The current operation mode and removal queue are as follows:

[0081] Group 1: IF line A, IF line B;

[0082] Group 2: JB Line B;

[0083] Group 3: H power plant units;

[0084] [S4] Monitor the power restoration conditions and continuously monitor whether the power restoration conditions are met; within 300 seconds from the time T0 when the fault is first discovered in step [S2.2], if the power restoration conditions are detected to be met, execute the power restoration strategy and close the open-loop point circuit breaker; if the power restoration conditions are not detected, if the voltage in the fault area meets the conditions within 2 hours from the time T0 when the fault is first discovered in step [S2.2], close the open-loop point circuit breaker; the power restoration condition refers to the loss of voltage on all buses in the fault area;

[0085] Specifically, if all busbars with a voltage level of 220kV in stations E, F, C, and B are without voltage, the power restoration strategy will be executed and the spare switches in the GH A and B double-circuit lines will be closed; otherwise, the system will wait until all busbars with a voltage level of 220kV in stations E, F, C, and B are without voltage before closing the spare switches in the GH A and B double-circuit lines.

[0086] [S5] Remote control closing open loop point circuit breaker:

[0087] If the remote control of single-circuit backup power supply or dual-circuit backup power supply is successful, then I = Detect whether the bus voltage at the fault location is restored within 100s; if any bus voltage is restored, it is determined that the self-healing power restoration is successful; otherwise, it is determined that the self-healing power restoration has failed;

[0088] A) If the remote control of the single-circuit backup power supply fails, the self-healing power restoration is deemed to have failed;

[0089] B) If the remote control of the dual-circuit backup power supply fails, the following measures shall be taken depending on the working conditions of the 1# and 2# circuits of the dual-circuit backup power supply:

[0090] B1) When the remote closing of the backup switch of circuit 1# fails, based on the power flow calculation results obtained by the advanced power system application software PAS, a remote closing command is issued if circuit 2# is not overloaded; if circuit 2# is overloaded, the self-healing system instance is discharged;

[0091] B2) When the remote closing of the 1# loop standby switch is successful and the remote closing of the 2# loop standby switch fails, determine whether the 1# loop is overloaded based on the real-time value; if it is overloaded, send a remote control command to trip the 1# loop standby switch and send an alarm signal at the same time; if the remote control tripping of the 1# loop standby switch fails, an alarm signal needs to be sent, and the dispatcher will perform subsequent operations and processing.

[0092] Specifically, if the number of spare lines in the GH A and B double-circuit lines is one, then a single-circuit spare is used; if the number is two, then a double-circuit spare is used. The first operating switch is the GH A line switch, and the second operating switch is the GH B line switch.

[0093] After the remote control of the spare line in the GH A and B double-circuit lines is successful, (T I) time to check whether the 220kV bus voltage of E, F, C, and B stations is restored.

[0094] If any bus voltage is restored, the self-healing power restoration is considered successful; otherwise, the self-healing power restoration is considered a failure.

[0095] If single-circuit backup is used and remote control fails, it is determined that self-healing power restoration has failed;

[0096] If the remote control fails in the case of double backup, it is divided into:

[0097] ① When the GH line A switch fails to close remotely, based on the PAS power flow calculation results, the standby GH line B switch will issue a remote closing command if the line is not overloaded; if the line is overloaded, the self-healing system will discharge;

[0098] ② When the GH line A switch is remotely closed successfully and the GH line B switch is remotely closed failed, determine whether the GH line A is overloaded based on the real-time collected active value.

[0099] If overloaded, a remote control command will be sent to trip the GH A line switch and send an alarm signal at the same time.

[0100] If the remote control to trip the GH line A switch fails, an alarm signal must be sent (subsequent operation and processing by the dispatcher).

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for monitoring and locating power grid faults and self-healing power restoration control, which creates a self-healing system instance based on a self-healing system model, implements regional power grid fault monitoring and locating, automatically disconnects generator sets in the faulty area, remotely closes open-loop circuit breakers, and restores power through a backup power source; characterized in that: include: [S1] Charge and discharge processing: If the backup power supply of the self-healing system instance does not meet the charging conditions, it will remain in the discharge state. If the charging conditions are met, it will be successfully charged after a delay; If the charging conditions are not met during the charging process, the charging will stop; after the charging is completed and the discharge conditions are met, the discharge will be instantaneous or delayed depending on the conditions. [S2] Fault monitoring and location: adopts "switch tripping + switch no current + total accident signal" multi-condition comprehensive judgment; [S2.1] When the backup power supply of the self-healing system instance is in the charging state, continuously monitor the lines in the fault monitoring area that are in normal operation. If conditions 1 and 2 are simultaneously met, a fault is determined to have occurred. Condition 1: The switches on both sides of each circuit in all normally operating lines in the fault monitoring area are tripped, and the tripped switches have no current and the active power of the switches is lower than the commissioning set value; Condition 2: Any circuit breaker in all normally operating lines in the fault monitoring area feeds back a total fault signal; [S2.2] If the fault persists and lasts longer than the threshold time T T =8s, fault location is successful; record the time when the fault is first discovered T0; [S3] Removal of units within the undervoltage range: To prevent damage to generator sets caused by asynchronous closing, the self-healing system instance removes units within the undervoltage range after the fault is successfully located. The removal queue is generated based on the monitoring points in the power plant monitoring area of ​​the self-healing system instance. The removal principle is to issue remote control commands based on the logic of serial control within the same substation and concurrent control between different substations. Whether the unit removal is successful does not affect the continued operation of the self-healing system instance. [S4] Monitoring power restoration conditions, and continuously monitoring whether the power restoration conditions are met; If, within 300 seconds from the time T0 when the fault is first discovered in step [S2.2], the power restoration condition is detected, the power restoration strategy is executed and the open-loop point circuit breaker is closed; If the power restoration condition is not met, and the voltage in the fault area meets the condition within 2 hours from the time T0 when the fault was first discovered in step [S2.2], the open-loop circuit breaker is closed; the power restoration condition refers to the loss of voltage on all buses in the fault area; [S5] Remote control closing open loop point circuit breaker: If the remote control of single-circuit backup power supply or dual-circuit backup power supply is successful, then I = Detect whether the bus voltage at the fault location is restored within 100s; if any bus voltage is restored, it is determined that the self-healing power restoration is successful; otherwise, it is determined that the self-healing power restoration has failed; A) If the remote control of the single-circuit backup power supply fails, the self-healing power restoration is deemed to have failed; B) If the remote control of the dual-circuit backup power supply fails, the following measures shall be taken depending on the working conditions of the 1# and 2# circuits of the dual-circuit backup power supply: B1) When the remote closing of the backup switch of circuit 1# fails, based on the power flow calculation results obtained by the advanced power system application software PAS, a remote closing command is issued if circuit 2# is not overloaded; if circuit 2# is overloaded, the self-healing system instance is discharged; B2) When the remote closing of the 1# loop standby switch is successful and the remote closing of the 2# loop standby switch fails, determine whether the 1# loop is overloaded based on the real-time value; if it is overloaded, send a remote control command to trip the 1# loop standby switch and send an alarm signal at the same time; if the remote control tripping of the 1# loop standby switch fails, an alarm signal needs to be sent, and the dispatcher will perform subsequent operations and processing.

2. A method for monitoring and locating power grid faults and controlling self-healing and power restoration according to claim 1, characterized in that: The self-healing system model includes three levels: self-healing system instance, monitoring area, and monitoring point; each self-healing system instance includes one or more monitoring areas, and each monitoring area includes one or more monitoring points; The self-healing system instance refers to a general modeling method that creates one or more groups of independently modeled, non-interfering self-healing system instances, which are applicable to the operation mode of fixed power grid faults and fixed backup lines; The monitoring areas include a fault monitoring area, a transfer monitoring area, an overload monitoring area, and a power plant monitoring area; the fault monitoring area records the fault monitoring equipment and is responsible for fault identification; the transfer monitoring area records the transfer monitoring equipment and is responsible for generating a power restoration strategy; the overload monitoring area records the overload monitoring equipment and is responsible for determining overload discharge; the power plant monitoring area records the power plant monitoring equipment and is responsible for determining the unit disconnection range; The monitoring points can add or delete monitoring equipment according to needs; the monitoring equipment includes busbars, lines, such as line switches and main transformer high-voltage switches.

3. A method for monitoring and locating power grid faults and controlling self-healing and power restoration according to claim 2, characterized in that: The charging condition in step [S1] refers to simultaneously satisfying conditions 3 and 4: Condition 3: At least one line in the fault monitoring area is operating normally; Condition 4: There is at least one line in the transfer monitoring area that is in standby status and has only one open-loop point.

4. A method for monitoring and locating power grid faults and controlling self-healing and power restoration according to claim 3, characterized in that: The discharge conditions in step [S1] include global discharge conditions and pre-fault discharge conditions; The global discharge condition is applicable to the entire process of power grid operation and is executed when any one of conditions 5 to 11 is met. The implementation method is instantaneous discharge. Condition 5: The self-healing system model exits, that is, the operator manually exits the self-healing system model; Condition 6: The self-healing system instance exits, that is, the operator manually exits the self-healing system instance; Condition 7: The lockout signal associated with the self-healing system instance is activated. Lockout signals are divided into temporary lockout and permanent lockout. After the permanent lockout signal is activated and reset, recharging is not possible even if the recharging conditions are met, and manual reset is required. After the temporary lockout signal is activated and reset, recharging is possible if the charging conditions are met. Condition 8: Any switch or knife switch in the self-healing system instance is abnormal, and a switch or knife switch in an intermediate position appears; Condition 9: The self-healing system instance processing times out; Condition 10: Failed to obtain any monitoring area of ​​the self-healing system instance; Condition 11: Self-healing system instance parameter modification: The operator modifies the parameters of a self-healing system instance through the interface; The pre-fault discharge conditions are applicable to the case where no fault occurs. If a fault occurs, this judgment is not performed. They include: Pre-fault discharge ①: Executed when any one of conditions 12 to 17 is met, with instantaneous discharge as the implementation method; Condition 12: The self-healing system instance topology is abnormal; Condition 13: The self-healing system instance has no open loop points or has multiple open loop points; Condition 14: No line in the fault monitoring area of ​​the self-healing system instance is in normal operation; Condition 15: The data collected from switches, circuit breakers, and busbars within the self-healing system instance modeling range is abnormal; Condition 16: The self-healing system instance overload calculation is based on simulated power flow values ​​and the power flow diverges; Condition 17: The self-healing system instance periodically calculates that the line power flow in the overload monitoring area exceeds the limit after power is restored; Pre-fault discharge ②: Executed when any one of conditions 18 to 19 is met and the duration TD1 = 20s is exceeded. The implementation method is delayed discharge. Condition 18: The self-healing system instance has no backup line; Condition 19: The self-healing system instance operates normally and the line manual trip signal action delays discharge; Pre-fault discharge ③: executed when condition 20 is met and the duration TD2 = 30s is exceeded, and the implementation method is delayed discharge; Condition 20: The switch of the normally operating line in the fault monitoring area of ​​the self-healing system instance changes from the closed position to the open position for a timeout.

5. A method for monitoring, locating, and controlling power grid faults according to claim 4, characterized in that: The busbar data collection anomalies described in condition 15 include: point inactivity, manual setting, invalid point value, poor communication status, exceeding reasonable limits, dead data, and collection failure.

6. A method for monitoring and locating power grid faults and controlling self-healing and power restoration according to claim 5, characterized in that: The commissioning value described in condition 1 in step [S2.1] = 5MW.

7. A method for monitoring and locating power grid faults and controlling self-healing and power restoration according to claim 6, characterized in that: The substations described in step [S3] include: power plant substations, transmission substations, distribution substations, and converter stations.

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