10kV urban power distribution network loop closing operation method and system

Abstract

The invention provides a 10kV urban power distribution network loop closing operation method and system, and belongs to the technical field of power distribution network loop closing operation. The method comprises the steps that a power grid topological graph is established, and two lines i and j needing loop closing are selected; loop closing simulation calculation of the loop closing impact current and the loop closing steady-state current is carried out; judging according to an auxiliary judgment condition; when the judgment result is that the loop closing operation can be carried out, executing the loop closing operation, and generating a path information graph after loop closing; and at the moments t1, t2 and t3 after the loop closing operation of the lines i and j is executed, the steady-state currents It1, It2 and It3 on the line i are checked based on a fixed value III of a first-stage switch protection II section of the line for judgment, and if the current value is not higher than 80% III for three times, the line operation mode is adjusted to reduce the risk of overload tripping.

Description

Technical Field

[0001] The present invention relates to the technical field of closed-loop operation of distribution networks, and in particular to a closed-loop operation method and system for a 10kV urban distribution network. Background Art

[0002] The closed loop of distribution network means that two distribution lines are respectively carried by the low-voltage busbars of two substations, and a contact switch and knife switch are set between the feeders. In normal operation, the low-voltage busbars of the two substations each carry the corresponding distribution lines, and the contact switch is in the disconnected state. When the whole or part of one of the feeders has a power outage, the contact switch and knife switch are closed first, and then the outgoing line switch or section switch is opened, and the power load of the whole or part of the line is carried by another feeder, thereby ensuring uninterrupted power supply.

[0003] Before the closing operation, it is necessary to confirm whether the conditions for closing the loop are met on both sides of the closing point. It is usually considered that the voltage difference between the two substation feeders is within 20%, which means the conditions for closing the loop are met. However, after the closing, the 10KV line transfers a large amount of high-voltage system load, and the 10KV system is at risk of overload tripping. It is very likely that the 10KV equipment will start the protection action again in a short time. If the steady-state current after the closing exceeds the maximum current carrying capacity of the line, it will burn out the equipment on the line, causing challenges to users' safe and reliable use of electricity, and there are also major safety hazards to personnel and equipment themselves. Summary of the invention

[0004] In view of this, the present invention provides a 10kV urban distribution network closing operation method and system, which monitors the system load condition after the closing of the loop and makes line adjustments when it is determined that the system has an overload tripping risk, so as to reduce the tripping probability after the closing of the loop and improve the reliability of power supply.

[0005] The technical solution adopted by the embodiment of the present invention to solve the technical problem is:

[0006] A 10kV urban distribution network ring closing operation method, comprising:

[0007] Step S1, establish a power grid topology map and select two lines i and j that need to be closed;

[0008] Step S2, querying the path of the closed loop and parameter information of the closed loop switch, and obtaining the voltage and power parameters of the two lines before the current closed loop, and performing closed loop simulation calculation of the closed loop impact current and the closed loop steady-state current;

[0009] Step S3, judging whether the closing operation can be performed according to the auxiliary discrimination conditions, wherein the auxiliary discrimination conditions include: the phase angle difference on both sides of the closing point is less than 20 degrees, the voltage difference on both sides of the closing point is less than 20%, the closing impulse current is less than the switch protection setting value, and the closing steady-state current is less than the maximum load capacity of the line; wherein the switch protection setting values ​​and corresponding protection functions of each section switch in the line are not all the same;

[0010] Step S4, when the result of step S3 is that the loop closing operation can be performed, the loop closing operation is performed, and a path information diagram after the loop closing is generated, and the power flow distribution after the loop closing is calculated;

[0011] Step S5, remodeling and calculating the automatic switch setting value according to the path information graph and the automatic switch distribution, and automatically sending it to the equipment operation and maintenance unit;

[0012] Step S6: At time t1 after the closing operation of lines i and j is completed, the line primary switch protection II stage constant I II Check the steady-state current I on line i t1 ; Among them, if I is satisfied t1 ≥ 80% I II , it is confirmed that the system is in a safe and stable operating state after the loop is closed; if I t1 <80%I II , it is confirmed that the system is not in a safe and stable operating state after the loop is closed, and there is a risk of overload tripping;

[0013] Step S7, at I t1 <80%I II In this case, at time t2 after the closing operation is completed, based on the line primary switch protection II section setting I II Check the steady-state current I on the line t2 ;

[0014] Step S8, at I t2 <80%I II In this case, at time t3 after the closing operation is completed, based on the line primary switch protection II section setting I II Check the steady-state current I on the line t3 ;if I t3 <80%I II , it is confirmed that the system always has the risk of overload tripping after the loop is closed;

[0015] Step S9, in I t3 <80%I II In such cases, adjust the line operation mode to reduce the risk of overload tripping;

[0016] The specific implementation of step S9 of adjusting the line operation mode includes:

[0017] Step S91, adjusting the fixed value of the first-stage switch section II of the line, and increasing the fixed value of the first-stage switch section II of the line by 5%;

[0018] or,

[0019] Step S92, selecting line k that is in multiple contact with line j to close the loop, wherein the closing process adopts the steps described in steps S1-S5;

[0020] Step S93, selecting a cut-off point on the line between lines i and j, cutting off line j, and the segment switch corresponding to the cut-off point is located between lines k and j.

[0021] Preferably, the step S2 comprises:

[0022] Step S21, establishing an equivalent circuit including lines i and j according to the power grid topology, wherein the equivalent circuit is a distribution ring equivalent network obtained by equivalently retaining the substation 10kV bus and the feeder to the closing point for the part above the 10kV bus;

[0023] Step S22, calculate the closed-loop steady-state current

[0024]

[0025]

[0026]

[0027] Z S =R0+jX0+R i +jX i +R j +jX j

[0028] Where: is the initial current of feeder i and j before the loop is closed; is the voltage value on both sides of the closing point; After the loop is closed, the voltage at the closing point The loop current caused by the inequality; R0, X0 are the equivalent impedances of the parts above 10kV busbar; R i , X i is the equivalent resistance and reactance of 10kV feeder i; R j , X j is the equivalent resistance and reactance of 10kV feeder j;

[0029]

[0030]

[0031] Where: P i , Q i is the initial active power and initial reactive power of 10kV feeder i, P j , Q j is the initial active power and initial reactive power of 10kV feeder j, U N The rated voltage U of the 10kV line N =10.5kV, r is the resistance per unit length of the line, x is the reactance per unit length of the line, L i is the total length from the busbar of the substation to the closing point of feeder i, L j is the total length from the busbar of the substation to which feeder j belongs to the closing point;

[0032] Step S23, calculating the closed-loop impulse current I P :

[0033] I P =kI1

[0034] Where I1 is the closed-loop steady-state current The effective value of k is the maximum impact coefficient, which is 1.62.

[0035] Preferably, the preset schemes of the switch protection settings in step S3 include:

[0036] The switch protection setting includes a current setting and a time setting, and the protection function is tripping protection or sending an alarm message to the automation system master station;

[0037] In the switch protection setting of the first-stage switch, the current setting is: the substation outgoing line switch protection setting / anti-coordination coefficient; the time setting is: the substation outgoing line switch protection setting-△T, △T is the time difference;

[0038] In the switch protection setting of the n-stage sectional switch after the first-stage switch, the current setting is: the protection setting of the n-1th sectional switch / the anti-coordination coefficient, n≥2, when n=2, the calculation is based on the switch protection setting of the first-stage switch, and the anti-coordination coefficient has a value range of less than 1.5; the time setting is: the protection setting of the n-1th sectional switch - △T, △T is the time difference, when n=2, the calculation is based on the switch protection setting of the first-stage switch; the time difference has a value range of 0.1s to 0.2s;

[0039] The protection functions of the first-stage switch include trip protection and alarm;

[0040] When there is a branch switch under the nth section switch, the protection functions of the nth section switch include tripping protection and alarm;

[0041] When there is no branch switch under the nth section switch, the protection function of the nth section switch includes an alarm.

[0042] Preferably, the anti-matching coefficient is 1.1, and the time difference is 0.1s.

[0043] Preferably, when the phase angle difference between the two sides of the closing point in the auxiliary judgment condition is not satisfied and is less than 20 degrees, the corresponding solution is to adjust the generator parameters;

[0044] When the auxiliary judgment condition that the voltage difference on both sides of the closing point is less than 20% is not met, the corresponding solution is to adjust the voltage of the upper-level substation;

[0045] When the closing-loop impact current in the auxiliary judgment condition is not less than the switch protection setting condition, the corresponding solution is to adjust the output size and line current of the generator;

[0046] When the auxiliary judgment condition that the closed-loop steady-state current is less than the maximum load capacity of the line is not met, the corresponding solution is to adjust the output size of the power generation party and the line current.

[0047] Preferably, the line first-stage switch protection II stage setting value I II is the overcurrent setting; time t1 is 30 minutes after the loop is closed, time t2 is 60 minutes after the loop is closed, and time t3 is 120 minutes after the loop is closed.

[0048] Preferably, after step S5 and before step S6, the method further includes: step S10, if the result of step S3 is that the loop closing operation cannot be performed, issuing an early warning, indicating the cause of failure, and generating a solution; the solution includes adjusting the voltage of the upper-level substation, adjusting the output of the power generator and the line current, and adjusting the generator parameters.

[0049] Furthermore, the present invention provides a 10kV urban distribution network ring closing operation method system for executing the aforementioned method.

[0050] It can be seen from the above technical scheme that the 10kV urban distribution network closing operation method provided by the embodiment of the present invention first establishes a power grid topology diagram, selects two lines i and j that need to be closed, queries the closing path and parameter information of the closing switch, obtains the voltage and power parameters of the two lines before the current closing, and performs closing simulation calculations of the closing impulse current and the closing steady-state current; determines whether the closing operation can be performed according to the auxiliary judgment conditions, wherein the auxiliary judgment conditions include: the phase angle difference on both sides of the closing point is less than 20 degrees, the voltage difference on both sides of the closing point is less than 20%, and the closing impulse current is less than the opening current. The protection setting and the closed-loop steady-state current are less than the maximum load capacity of the line; the switch protection setting and the corresponding protection function of each section switch in the line are not all the same; when the judgment result is that the closed-loop operation can be performed, the closed-loop operation is performed, and the path information diagram after the closed-loop operation is generated, and the power flow distribution after the closed-loop operation is calculated; according to the path information diagram and the distribution of the automated switches, the automated switch setting is re-modeled and calculated and automatically sent to the equipment operation and maintenance unit; at t1, t2, and t3 after the closed-loop operation of lines i and j is completed, based on the line first-level switch protection II section setting I II Check the steady-state current I on line i t1 ,I t2 ,I t3 If the current value is higher than 80% I II , then adjust the line operation mode to reduce the risk of overload tripping. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The present invention is a flow chart of the 10kV urban distribution network ring closing operation method.

[0052] Figure 2 This is a schematic diagram of the distribution network loop.

[0053] Figure 3 This is the equivalent network diagram of the distribution network closed loop.

[0054] Figure 4 This is the model diagram of uniform distribution of 10kV feeder load.

[0055] Figure 5 This is a diagram of the principle architecture of the auxiliary identification program.

[0056] Figure 6 This is a flow chart of the closed-loop operation using auxiliary procedures.

[0057] Figure 7 It is a block diagram of an electronic device used to implement the 10kV urban distribution network ring closing operation method of the present invention. DETAILED DESCRIPTION

[0058] The technical scheme and technical effects of the present invention are further elaborated in detail below in conjunction with the accompanying drawings of the present invention.

[0059] like Figure 1 As shown, the present invention provides a 10kV urban distribution network ring closing operation method, comprising:

[0060] Step S1, establish a power grid topology map and select two lines i and j that need to be closed;

[0061] Step S2, querying the path of the closed loop and parameter information of the closed loop switch, and obtaining the voltage and power parameters of the two lines before the current closed loop, and performing closed loop simulation calculation of the closed loop impact current and the closed loop steady-state current;

[0062] Step S3, judging whether the closing operation can be performed according to the auxiliary discrimination conditions, wherein the auxiliary discrimination conditions include: the phase angle difference on both sides of the closing point is less than 20 degrees, the voltage difference on both sides of the closing point is less than 20%, the closing impulse current is less than the switch protection setting value, and the closing steady-state current is less than the maximum load capacity of the line; wherein the switch protection setting values ​​and corresponding protection functions of each section switch in the line are not all the same;

[0063] Step S4, when the result of step S3 is that the loop closing operation can be performed, the loop closing operation is performed, and a path information diagram after the loop closing is generated, and the power flow distribution after the loop closing is calculated; in addition, if the result of step S3 is that the loop closing operation cannot be performed, an early warning is issued, the cause of the failure is prompted, and a solution is generated; the solution includes adjusting the voltage of the upper-level substation, adjusting the output size and line current of the power generation party, and adjusting the generator parameters.

[0064] Step S5, remodeling and calculating the automatic switch setting value according to the path information graph and the automatic switch distribution, and automatically sending it to the equipment operation and maintenance unit;

[0065] Step S6: At time t1 after the closing operation of lines i and j is completed, the line primary switch protection II stage constant I II Check the steady-state current I on line i t1 ; Among them, if I is satisfied t1 ≥ 80% I II , it is confirmed that the system is in a safe and stable operating state after the loop is closed; if I t1 <80%I II , it is confirmed that the system is not in a safe and stable operating state after the loop is closed, and there is a risk of overload tripping;

[0066] Step S7, at I t1 <80%I II In this case, at time t2 after the closing operation is completed, based on the line primary switch protection II section setting I IICheck the steady-state current I on the line t2 ;

[0067] Step S8, at I t2 <80%I II In this case, at time t3 after the closing operation is completed, based on the line primary switch protection II section setting I II Check the steady-state current I on the line t3 ;if I t3 <80%I II , it is confirmed that the system always has the risk of overload tripping after the loop is closed;

[0068] Step S9, in I t3 <80%I II In such cases, adjust the line operation mode to reduce the risk of overload tripping;

[0069] Line first-stage switch protection II stage setting I II is the overcurrent setting; time t1 is 30 minutes after the loop is closed, time t2 is 60 minutes after the loop is closed, and time t3 is 120 minutes after the loop is closed.

[0070] Furthermore, there are two ways to adjust the line operation mode in step S9:

[0071] The first method is to adjust the fixed value of the first-stage switch section II of the line and increase the fixed value of the first-stage switch section II of the line by 5%; refer to Table 1 for example:

[0072]

[0073] Table 1

[0074] The second type is:

[0075] Step S92, selecting line k that is in multiple contact with line j to close the loop, wherein the closing process adopts the steps S1-S5;

[0076] Step S93, selecting a cut-off point on the line between lines i and j, cutting off line j, and the segment switch corresponding to the cut-off point is located between lines k and j.

[0077] Step S6, if the result of step S3 is that the loop closing operation cannot be performed, an early warning is issued, the cause of the failure is prompted, and a solution is generated; the solution includes adjusting the voltage of the upper-level substation, adjusting the output size and line current of the power generation party, and adjusting the generator parameters.

[0078] In step S2, in the calculation of the closed-loop steady-state current, first Figure 2The topological analysis of the structural diagram shows that the topological structure of the 10kV busbar through the feeder to the closing point is the same. The part above the 10kV busbar is part of the ring network, and the impedance can be equivalently converted to the 10kV busbar side. Therefore, the distribution closing equivalent network is obtained by equivalently retaining the substation 10kV busbar and the feeder to the closing point for the part above the 10kV busbar.

[0079] Step S21: Establish an equivalent circuit reference including lines i and j according to the power grid topology. Figure 3 As shown, the equivalent circuit is the distribution ring equivalent network obtained by equivalently retaining the part above the 10kV busbar and the feeder to the closing point of the substation;

[0080] Step S22, calculate the closed-loop steady-state current

[0081]

[0082] Z S =R0+jX0+R i +jX i +R j +jX j (4)

[0083] Where: is the initial current of feeder i and j before the loop is closed; is the voltage value on both sides of the closing point; After the loop is closed, the voltage at the closing point The loop current caused by the inequality; R0, X0 are the equivalent impedances of the parts above 10kV busbar; R i , X i is the equivalent resistance and reactance of 10kV feeder i; R j , X j is the equivalent resistance and reactance of 10kV feeder j;

[0084] The voltage of two closing points is calculated by the following formula:

[0085]

[0086] Where: P i , Q i is the initial active power and initial reactive power of 10kV feeder i, P j , Q j is the initial active power and initial reactive power of 10kV feeder j, U N The rated voltage U of the 10kV line N =10.5kV, r is the resistance per unit length of the line, x is the reactance per unit length of the line, L iis the total length from the busbar of the substation to the closing point of feeder i, L j is the total length from the busbar of the substation to which feeder j belongs to the closing point;

[0087] Step S23, calculating the closed-loop impulse current I P :

[0088] I P =kI1 (7)

[0089] Where I1 is the closed-loop steady-state current The effective value of k is the maximum impact coefficient, which is 1.62.

[0090] The preset schemes of the protection settings of each switch in step S3 include:

[0091] The switch protection setting includes current setting and time setting. The protection function is tripping protection or sending alarm messages to the automation system master station.

[0092] In the switch protection setting of the first-stage switch, the current setting is: the substation outgoing line switch protection setting / anti-coordination coefficient; the time setting is: the substation outgoing line switch protection setting-△T, △T is the time difference;

[0093] In the switch protection setting of the n-stage sectional switch after the first-stage switch, the current setting is: the protection setting of the n-1th sectional switch / the anti-coordination coefficient, n≥2. When n=2, the calculation is based on the switch protection setting of the first-stage switch, and the anti-coordination coefficient is in the range of less than 1.5; the time setting is: the protection setting of the n-1th sectional switch - △T, △T is the time difference, when n=2, the calculation is based on the switch protection setting of the first-stage switch; the time difference is in the range of 0.1s to 0.2s; the anti-coordination coefficient is 1.1, and the time difference is 0.1s;

[0094] The protection functions of the primary switch include trip protection and alarm;

[0095] The loop closing auxiliary determination conditions adopted by the present invention include:

[0096] 1. The phase angle difference on both sides of the closing point is less than 20 degrees;

[0097] 2. The pressure difference on both sides of the closing point is less than 20%;

[0098] 3. The loop impact current is less than the switch protection setting value;

[0099] 4. The steady-state current of the closed loop is less than the maximum load capacity of the line (the steady-state current after the closed loop should be less than the maximum load capacity of the two lines, otherwise it is easy to burn the line. The maximum load capacity of the line can be determined by the material model and wire diameter of the line);

[0100] All auxiliary conditions must be met before the loop closing operation can be considered possible. When some auxiliary conditions are not met, the following solutions can be used for adjustment:

[0101] When there is a branch switch under the nth section switch, the protection functions of the nth section switch include tripping protection and alarm;

[0102] When there is no branch switch under the nth section switch, the protection function of the nth section switch includes an alarm.

[0103] When the phase angle difference on both sides of the closing point is less than 20 degrees in the auxiliary judgment condition, the corresponding solution is to adjust the generator parameters;

[0104] When the auxiliary judgment condition that the voltage difference on both sides of the closing point is less than 20% is not met, the corresponding solution is to adjust the voltage of the upper-level substation;

[0105] When the closing-loop impact current in the auxiliary judgment condition is not less than the switch protection setting condition, the corresponding solution is to adjust the output size and line current of the generator;

[0106] When the auxiliary judgment condition that the closed-loop steady-state current is less than the maximum load capacity of the line is not met, the corresponding solution is to adjust the output size of the power generation party and the line current.

[0107] Furthermore, the present invention provides a 10kV urban distribution network ring closing operation method system, which can be implemented with software and used to implement Figure 1 The method shown.

[0108] According to an embodiment of the present disclosure, the present disclosure also provides an electronic device, a readable storage medium and a computer program product.

[0109] Figure 7 A schematic block diagram of an example electronic device 700 that can be used to implement an embodiment of the present disclosure is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present disclosure described and / or required herein.

[0110] like Figure 7As shown, the device 700 includes a computing unit 701, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 702 or a computer program loaded from a storage unit 708 into a random access memory (RAM) 703. In the RAM 703, various programs and data required for the operation of the device 700 can also be stored. The computing unit 701, the ROM 702, and the RAM 703 are connected to each other via a bus 704. An input / output (I / O) interface 705 is also connected to the bus 704.

[0111] A number of components in the device 700 are connected to the I / O interface 705, including: an input unit 706, such as a keyboard, a mouse, etc.; an output unit 707, such as various types of displays, speakers, etc.; a storage unit 708, such as a disk, an optical disk, etc.; and a communication unit 709, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 709 allows the device 700 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0112] The computing unit 701 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the computing unit 701 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any appropriate processors, controllers, microcontrollers, etc. The computing unit 701 performs the various methods and processes described above, such as the 10kV urban distribution network closed-loop operation method. For example, in some embodiments, the 10kV urban distribution network closed-loop operation method may be implemented as a computer software program, which is tangibly contained in a machine-readable medium, such as a storage unit 708. In some embodiments, part or all of the computer program may be loaded and / or installed on the device 700 via the ROM 702 and / or the communication unit 709. When the computer program is loaded into the RAM 703 and executed by the computing unit 701, one or more steps of the 10kV urban distribution network closed-loop operation method described above may be performed. Alternatively, in other embodiments, the computing unit 701 may be configured to execute the 10 kV urban distribution network ring closing operation method in any other appropriate manner (for example, by means of firmware).

[0113] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0114] The program code for implementing the method of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0115] In the context of the present disclosure, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0116] To provide interaction with a user, the systems and techniques described herein can be implemented on a computer having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other types of devices can also be used to provide interaction with the user; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0117] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0118] A computer system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The relationship between the client and the server is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0119] What is disclosed above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A 10kV urban distribution network ring closing operation method, characterized in that: include: Step S1, establish a power grid topology map and select two lines i and j that need to be closed; Step S2, querying the path of the closed loop and parameter information of the closed loop switch, and obtaining the voltage and power parameters of the two lines before the current closed loop, and performing closed loop simulation calculation of the closed loop impact current and the closed loop steady-state current; Step S3, judging whether the closing operation can be performed according to the auxiliary discrimination conditions, wherein the auxiliary discrimination conditions include: the phase angle difference on both sides of the closing point is less than 20 degrees, the voltage difference on both sides of the closing point is less than 20%, the closing impulse current is less than the switch protection setting value, and the closing steady-state current is less than the maximum load capacity of the line; wherein the switch protection setting values ​​and corresponding protection functions of each section switch in the line are not all the same; Step S4, when the result of step S3 is that the loop closing operation can be performed, the loop closing operation is performed, and a path information diagram after the loop closing is generated, and the power flow distribution after the loop closing is calculated; Step S5, remodeling and calculating the automatic switch setting value according to the path information graph and the automatic switch distribution, and automatically sending it to the equipment operation and maintenance unit; Step S6: At time t1 after the closing operation of lines i and j is completed, the line primary switch protection II stage constant I II Check the steady-state current I on line i t1 ; Among them, if I is satisfied t1 ≥ 80% I II , it is confirmed that the system is in a safe and stable operating state after the loop is closed; if I t1 <80%I II , it is confirmed that the system is not in a safe and stable operating state after the loop is closed, and there is a risk of overload tripping; Step S7, at I t1 <80%I II In this case, at time t2 after the closing operation is completed, based on the line primary switch protection II section setting I II Check the steady-state current I on the line t2 ; Step S8, at I t2 <80%I II In this case, at time t3 after the closing operation is completed, based on the line primary switch protection II section setting I II Check the steady-state current I on the line t3 ;if I t3 <80%I II , it is confirmed that the system always has the risk of overload tripping after the loop is closed; Step S9, in I t3 <80%I II In this case, the line operation mode is adjusted to reduce the risk of overload tripping; the specific implementation of step S9 of adjusting the line operation mode includes: Step S91, adjusting the fixed value of the first-stage switch section II of the line, and increasing the fixed value of the first-stage switch section II of the line by 5%; or, Step S92, selecting line k that is in multiple contact with line j to close the loop, wherein the closing process adopts the steps described in steps S1-S5; Step S93, selecting a cut-off point on the line between lines i and j, cutting off line j, and the segment switch corresponding to the cut-off point is located between lines k and j.

2. The 10kV urban distribution network closing ring operation method according to claim 1, characterized in that: The step S2 comprises: Step S21, establishing an equivalent circuit including lines i and j according to the power grid topology, wherein the equivalent circuit is a distribution ring equivalent network obtained by equivalently retaining the substation 10kV bus and the feeder to the closing point for the part above the 10kV bus; Step S22, calculate the closed-loop steady-state current Z S =R0+jX0+R i +jX i +R j +jX j Where: is the initial current of feeder i and j before the loop is closed; is the voltage value on both sides of the closing point; After the loop is closed, the voltage at the closing point The loop current caused by the inequality; R0, X0 are the equivalent impedances of the parts above 10kV busbar; R i , X i is the equivalent resistance and reactance of 10kV feeder i; R j , X j is the equivalent resistance and reactance of 10kV feeder j; Where: P i , Q i is the initial active power and initial reactive power of 10kV feeder i, P j , Q j is the initial active power and initial reactive power of 10kV feeder j, U N The rated voltage U of the 10kV line N =10.5kV, r is the resistance per unit length of the line, x is the reactance per unit length of the line, L i is the total length from the busbar of the substation to the closing point of feeder i, L j is the total length from the busbar of the substation to which feeder j belongs to the closing point; Step S23, calculating the closed-loop impulse current I P : I P =kI1 Where I1 is the closed-loop steady-state current The effective value of k is the maximum impact coefficient, which is 1.

62.

3. The 10kV urban distribution network closing ring operation method according to claim 2, characterized in that: The preset schemes of the switch protection settings in step S3 include: The switch protection setting includes a current setting and a time setting, and the protection function is tripping protection or sending an alarm message to the automation system master station; In the switch protection setting of the first-stage switch, the current setting is: the substation outgoing line switch protection setting / anti-coordination coefficient; the time setting is: the substation outgoing line switch protection setting-△T, △T is the time difference; In the switch protection setting of the n-stage sectional switch after the first-stage switch, the current setting is: the protection setting of the n-1th sectional switch / the anti-coordination coefficient, n≥2, when n=2, the calculation is based on the switch protection setting of the first-stage switch, and the anti-coordination coefficient has a value range of less than 1.5; the time setting is: the protection setting of the n-1th sectional switch - △T, △T is the time difference, when n=2, the calculation is based on the switch protection setting of the first-stage switch; the time difference has a value range of 0.1s to 0.2s; The protection functions of the first-stage switch include trip protection and alarm; When there is a branch switch under the nth section switch, the protection functions of the nth section switch include tripping protection and alarm; When there is no branch switch under the nth section switch, the protection function of the nth section switch includes an alarm.

4. The 10kV urban distribution network closing ring operation method according to claim 3, characterized in that: The anti-matching coefficient is 1.1, and the time difference is 0.1s.

5. The 10kV urban distribution network closing operation method according to claim 4, characterized in that: When the phase angle difference on both sides of the closing point is less than 20 degrees in the auxiliary judgment condition, the corresponding solution is to adjust the generator parameters; When the auxiliary judgment condition that the voltage difference on both sides of the closing point is less than 20% is not met, the corresponding solution is to adjust the voltage of the upper-level substation; When the closing-loop impact current in the auxiliary judgment condition is not less than the switch protection setting condition, the corresponding solution is to adjust the output size and line current of the generator; When the auxiliary judgment condition that the closed-loop steady-state current is less than the maximum load capacity of the line is not met, the corresponding solution is to adjust the output size of the power generation party and the line current.

6. The 10kV urban distribution network closing ring operation method according to claim 1, characterized in that: Line primary switch protection II stage setting I II is the overcurrent setting; time t1 is 30 minutes after the loop is closed, time t2 is 60 minutes after the loop is closed, and time t3 is 120 minutes after the loop is closed.

7. The 10kV urban distribution network closing ring operation method according to claim 1, characterized in that: After step S5 and before step S6, the method further includes: step S10, if the result of step S3 is that the loop closing operation cannot be performed, issuing an early warning, indicating the cause of failure, and generating a solution; the solution includes adjusting the voltage of the upper-level substation, adjusting the output size and line current of the power generator, and adjusting the generator parameters.

8. A 10kV urban distribution network closed-loop operating system, characterized in that: Used to execute the method according to any one of claims 1 to 7.

9. An electronic device, characterized in that: include: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the method according to any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium storing computer instructions, wherein: The computer instructions are used to cause the computer to execute the method according to any one of claims 1-7.

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