A time-limited adaptive reclosing method, device, system and medium for active distribution network

Abstract

A time-limited adaptive reclosing method for an active distribution network comprises the following steps: when the line outlet protection detects that a distribution line has a fault, a tripping action is executed, and the distributed power source IIDER connected to the distribution line performs low voltage ride-through according to the low voltage ride-through requirement; after the line outlet executes the tripping action, the bus side voltage U before the tripping is obtained. l , extract the line export protection action information; according to the bus side voltage U before tripping l The time t required for the anti-islanding protection of the distributed power source IIDER connected to the line to be activated is determined by the low voltage ride-through requirement. a ; Determine the required preset reclosing action time t according to the timing coordination relationship and protection action information r When the preset reclosing action time arrives, the distributed power source IIDER connected to the line is disconnected from the grid, the reclosing action is activated, and the outlet circuit breaker is controlled to reclose. This can significantly reduce the waiting time for the reclosing, and ensure the rapidity of the reclosing action as much as possible to improve the reliability of power supply, without relying on the communication network, and has good economic efficiency.

Description

Technical Field

[0001] The invention belongs to the field of electrical engineering relay protection, and in particular relates to a time-limited adaptive reclosing method, device, system and medium for an active distribution network. Background Art

[0002] When reclosing the active distribution network, the distributed energy resource (DER) must be cut off. In the traditional distribution network, after the system-side protection trips due to a fault in the distribution line, the reclosing will wait for about 2 seconds before taking action. The access of DER has changed the distribution network from a traditional single-power radial network to a distribution network with a multi-terminal power structure. The original distribution network protection and control strategy will be affected to a certain extent. After the system-side protection trips, if the DER is still connected to the fault point, the fault current is greater than 15A, and the fault point will not extinguish the arc. If the DER is still not disconnected from the grid during reclosing, the reclosing will fail. At the same time, the impact current generated by the asynchronous reclosing will bring secondary impacts to the distribution lines, DER and other equipment.

[0003] In an active distribution network, when a distribution line fails, the fault current output by the inverter interfaced distributed energy resource (IIDER) is limited and the current protection cannot operate reliably. The only option is to rely on the anti-islanding protection to cut off the IIDER, which will extend the waiting time for reclosing and seriously affect the power supply reliability.

[0004] In order to ensure that the distributed generation has been disconnected from the grid when reclosing, many scholars have proposed a strategy of checking no-pressure reclosing. For example, the literature [Li Yuqiang, Wang Zhiwen, Wang Weiqing, et al. The impact of photovoltaic access distribution network with LVRT capability on reclosing and countermeasures] gives a "check no-pressure" reclosing scheme. The check no-pressure reclosing method determines whether to reclose by detecting whether the line has pressure, but the check no-pressure reclosing method requires a voltage transformer on the line side. In practice, due to limited space in the substation, many substations are not equipped with line-side voltage transformers, and it is difficult to achieve reclosing by checking no pressure. If the condition of checking no pressure is not met, considering that DER needs to cross the fault when the system is disturbed, the reclosing action time limit should be greater than the anti-islanding protection action time limit, which will increase the waiting time of the reclosing and seriously affect the reliability of power supply.

[0005] The literature [Wu Yue, Fan Kaijun, Xu Bingyin, et al. Time-limit adaptive reclosing method for distribution network coordinated with anti-islanding protection [J]. Automation of Electric Power Systems, 2024, 48(03): 122-132.] proposed a time-limit adaptive reclosing method, which considered the timing coordination of reclosing and distributed generation anti-islanding protection, but did not comprehensively consider the timing coordination of distribution line outlet protection, reclosing and distributed generation anti-islanding protection. Summary of the invention

[0006] The object of the present invention is to solve the deficiencies of the above-mentioned prior art, thereby providing an active distribution network time-limited adaptive reclosing method, device, system and medium, which can significantly reduce the waiting time for reclosing, ensure the rapidity of reclosing action as much as possible, so as to improve power supply reliability, do not rely on communication networks, and have good economy.

[0007] A time-limit adaptive reclosing method for an active power distribution network comprises the following steps:

[0008] When the line outlet protection detects a fault in the distribution line, it will trip and the distributed power source IIDER connected to the distribution line will perform low voltage ride-through according to the low voltage ride-through requirements;

[0009] After the line exit performs the tripping action, obtain the bus side voltage U before tripping l , extract line exit protection action information;

[0010] According to the bus voltage U before tripping l The time t required for the anti-islanding protection of the distributed power source IIDER connected to the line is determined by the low voltage ride-through requirement. a ;

[0011] According to the staged current protection scheme, the time required for reclosing and anti-islanding protection to operate is t a The timing coordination relationship of the three and the protection action information determine the required preset reclosing action time t r ;

[0012] When the preset reclosing action time arrives, the distributed power source IIDER connected to the line is disconnected from the grid, and the reclosing action is executed to control the outlet circuit breaker to reclose.

[0013] Before a fault occurs, a staged current protection scheme is configured on the line outlet protection, and the low voltage ride-through requirements of the distributed power source IIDER connected to the line are configured in the reclosing control module.

[0014] The staged current protection scheme is divided into three stages: stage I, stage II, and stage III. The stage I protection action is instantaneous current quick break, and the response time is 0s; the stage II protection action is time-limited current quick break, and the response time is t Ⅱ ; The third stage protection action is time-limited overcurrent protection, and the response time is t Ⅲ .

[0015] According to the bus voltage U before tripping l The time t required for the anti-islanding protection of the distributed power source IIDER connected to the line is determined by the low voltage ride-through requirement. a Specifically:

[0016] The following formula is used to calculate the time t required for the anti-islanding protection action of the distributed power source IIDER connected to the line: a :

[0017]

[0018] Where U l It is the bus voltage before tripping.

[0019] If there are multiple distributed power sources IIDER connected to the line, the anti-islanding protection action time t of all distributed power sources IIDER is taken a The maximum value of .

[0020] According to the staged current protection scheme, the time required for reclosing and anti-islanding protection to operate is t a The timing coordination relationship of the three and the protection action information determine the required preset reclosing action time t r Specifically:

[0021] Determine the time t required for the staged current protection scheme, reclosing and anti-islanding protection to operate a The timing coordination relationship among the three is:

[0022]

[0023] Where, t r is the reclosing action time, t a It is the time required for the anti-islanding protection of the distributed power source IIDER connected to the line to take action, and Δt is the fault arc extinction time;

[0024] According to the extracted protection action information, the reclosing action time is calculated according to formula (2):

[0025] If the stage I protection is activated at the outlet, and there is no delay in the outlet protection, the reclosing action time is t r t a +Δt;

[0026] If the stage II protection is activated at the outlet, the outlet protection action delay is t Ⅱ , the reclosing control module is Ⅱ and t a For comparison, if t a >t Ⅱ , reclosing action time t r t a -t Ⅱ +Δt; if t a <t Ⅱ , if the reclosing action time t r is Δt;

[0027] If the stage III protection is activated at the exit, the exit protection action delay is t Ⅲ , the reclosing control module is Ⅲ and t a For comparison, if t a >t Ⅲ , then the reclosing action time t r t a -t Ⅲ +Δt; if t a <t Ⅲ , then the reclosing action time t r is Δt.

[0028] An active power distribution network time-limit adaptive reclosing device, comprising:

[0029] The line export protection module is used to execute the tripping action when the line export protection detects that the distribution line has a fault. The distributed power source IIDER connected to the distribution line performs low voltage ride-through according to the low voltage ride-through requirements;

[0030] The signal acquisition module is used to obtain the bus voltage U before tripping after the tripping action is performed at the line outlet. l , extract line exit protection action information;

[0031] The calculation module is used to calculate the bus voltage U before tripping. l The time t required for the anti-islanding protection of the distributed power source IIDER connected to the line is determined by the low voltage ride-through requirement. a ; According to the staged current protection scheme, the time required for reclosing and anti-islanding protection to operate is t a The timing coordination relationship of the three and the protection action information determine the required preset reclosing action time t r ;

[0032] The reclosing control module is used to execute the reclosing action and control the reclosing of the outlet circuit breaker when the preset reclosing action time arrives and the distributed power source IIDER connected to the line is disconnected from the grid.

[0033] It also includes a configuration module, which is used to configure a staged current protection scheme on the line outlet protection before a fault occurs, and configure the low voltage ride-through requirement of the distributed power source IIDER connected to the line in the reclosing control module.

[0034] The computing module is specifically used for:

[0035] The following formula is used to calculate the time t required for the anti-islanding protection action of the distributed power source IIDER connected to the line: a :

[0036]

[0037] Where U l It is the bus voltage before tripping.

[0038] The calculation module is also used to:

[0039] The timing coordination relationship determination module is specifically used to determine the timing coordination relationship as follows:

[0040]

[0041] Where, t r is the reclosing action time, t a It is the time required for the anti-islanding protection of the distributed power source IIDER connected to the line to take action, and Δt is the fault arc extinction time;

[0042] According to the extracted protection action information, the reclosing action time is calculated according to formula (2):

[0043] If the stage I protection is activated at the outlet, and there is no delay in the outlet protection, the reclosing action time is t r t a +Δt;

[0044] If the stage II protection is activated at the outlet, the outlet protection action delay is t Ⅱ , the reclosing control module is Ⅱ and t a For comparison, if t a >t Ⅱ , reclosing action time t r t a -t Ⅱ +Δt; if t a <t Ⅱ , if the reclosing action time t r is Δt;

[0045] If the stage III protection is activated at the exit, the exit protection action delay is t Ⅲ , the reclosing control module is Ⅲ and t a For comparison, if t a >t Ⅲ , then the reclosing action time t r t a -t Ⅲ +Δt; if t a <t Ⅲ , then the reclosing action time t r is Δt.

[0046] An active power distribution network time-limit adaptive reclosing control system, comprising: a computer-readable storage medium and a processor;

[0047] The computer-readable storage medium is used to store executable instructions;

[0048] The processor is used to read the executable instructions stored in the computer-readable storage medium to execute the active power distribution network time-limit adaptive reclosing method.

[0049] A non-transitory computer-readable storage medium stores a computer program, which, when executed by a processor, implements the active power distribution network time-limit adaptive reclosing method.

[0050] Compared with the prior art, the present invention has the following advantages:

[0051] 1. Comprehensively consider the timing coordination relationship between distribution line protection, reclosing and distributed power supply anti-islanding protection. Compared with the traditional scheme, the waiting time of reclosing can be significantly reduced, which is of great significance to improving power supply reliability.

[0052] 2. The present invention quantitatively provides the basis for setting the reclosing action time in coordination with the distribution line protection and the distributed power source anti-islanding protection. On the premise of meeting the reliability of the reclosing action, the rapidity of the reclosing action is guaranteed as much as possible to improve the power supply reliability.

[0053] 3. The implementation of the present invention does not require the installation of line-side voltage transformers, is independent of communication networks, and has good economic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a simplified diagram of the active power distribution circuit structure;

[0055] Figure 2 An implementation method for time-limited adaptive reclosing in active distribution networks;

[0056] Figure 3 It is the timing coordination relationship of distribution line outlet protection, reclosing and distributed power supply anti-islanding protection;

[0057] Figure 4 This is a circuit diagram of an active power distribution network according to an embodiment of the present invention. DETAILED DESCRIPTION

[0058] The present invention comprehensively considers the timing coordination relationship of active distribution line outlet protection, reclosing and distributed power supply anti-islanding protection. Figure 1The simple distribution line structure shown in the figure is used as an example for explanation. In the active distribution line, if a fault occurs, such as point F1 in the figure, the system side E and the distributed power source IIDER simultaneously provide current to the fault point, the system side outlet protection is activated, the outlet circuit breaker QF1 is tripped, IIDER is activated according to the low voltage ride-through requirements, the anti-islanding protection is activated, QF2 is activated, IIDER is disconnected from the grid, and the reclosing switch configured in QF1 is activated. If it is a transient fault, the power supply can be quickly restored. The flowchart of the implementation scheme of the active distribution network time-limited adaptive reclosing switch coordinated with the staged current protection and anti-islanding protection corresponding to the present invention is as follows: Figure 2 shown.

[0059] The present invention takes the stage current protection of the distribution line outlet protection configuration as an example to explain the timing coordination relationship between the distribution line outlet protection, the reclosing switch and the anti-islanding protection of the distributed power source. During the project implementation, the time-limit adaptive reclosing switch method can be set according to the current national standard "GB / T 33593-2017 Technical Requirements for Distributed Power Source Grid Connection". The IIDER can coordinate the action time of the time-limit adaptive reclosing switch with the action time of the anti-islanding protection according to the grid-off time determined by formula (1).

[0060]

[0061] Where, t a It is the low voltage ride-through time of IIDER and the time required for the anti-islanding protection action of the distributed power source IIDER connected to the line, in seconds, U l It is the bus voltage before tripping.

[0062] The specific implementation steps of the method of the present invention are as follows:

[0063] When the line outlet protection detects a fault in the distribution line, the system side and each IIDER simultaneously inject current into the fault point and perform a tripping action. The IIDER connected to the distribution line performs low voltage ride-through according to the low voltage ride-through requirements.

[0064] After the tripping action is executed, the reclosing is started, and the reclosing control module obtains the bus side voltage U before tripping l , extract the protection action information. The low voltage ride-through requirement of the IIDER connected to the line has been configured in the reclosing control module. According to formula (1), the time t required for the connected IIDER anti-islanding protection action is calculated a If there are multiple distributed power sources connected to the line, then t a Take the maximum value of all IIDER anti-islanding protection action times. According to formula (1), the anti-islanding protection action time range is [0.625s, 2s].

[0065] Taking the staged current protection of the distribution line outlet protection configuration as an example, the timing coordination relationship between the distribution line outlet protection, reclosing and distributed power supply anti-islanding protection is explained. Figure 3 The reclosing action time is shown in formula (2). Among them, the line outlet protection is configured with current instantaneous quick break (stage I protection, 0s quick action), time-limited current quick break (stage II protection, time setting value is t Ⅱ , which can be 0.3s) and time-limited overcurrent protection (stage III protection, the time setting value is t Ⅲ , which can be 1s. The specific value needs to satisfy the coordination relationship between the upper and lower level protections. Here we only take this as an example to illustrate the timing coordination relationship between the export protection, reclosing switch and IIDER anti-islanding protection).

[0066]

[0067] In formula (2), t r is the reclosing action time, Δt is the fault arc extinction time, which can be taken as 0.2s;

[0068] According to the extracted protection action information, the reclosing action time is calculated according to formula (2), as follows:

[0069] a) If the stage I protection is activated at the outlet and there is no delay in the outlet protection, then the reclosing action time is t a +Δt.

[0070] b) If the stage II protection is activated at the outlet, the delay of the outlet protection action is t Ⅱ , the reclosing control module is Ⅱ and t a For comparison, if

[0071] t a >t Ⅱ , then the reclosing action time is t a -t Ⅱ +Δt; if t a <t Ⅱ , then the reclosing action time is Δt.

[0072] c) If the stage III protection is activated at the exit, the exit protection action delay is t Ⅲ , the reclosing control module is Ⅲ and t a For comparison, if t a >t Ⅲ , then the reclosing action time is t a -t Ⅲ +Δt; if t a <t Ⅲ , then the reclosing action time is Δt.

[0073] (5) When the preset reclosing action time arrives, all distributed power sources are disconnected from the grid, and the reclosing action is executed to control the outlet circuit breaker to reclose.

[0074] According to the distributed power response time of GB / T33593-2017, the traditional reclosing scheme waits for 2s after the protection action. After the distributed power anti-islanding protection is actuated, the outlet circuit breaker is reclosed after the fault arc is extinguished (here, Δt = 0.2s).

[0075] If the protection is stage I protection action at the outlet, the traditional method requires the reclosing switch to act 2.2s after the fault occurs. With the scheme described in the present invention, the power supply can be restored at the shortest 0.825s (Δt=0.2s) after the fault, and at the longest 2.2s;

[0076] If the protection is stage II protection (here t Ⅱ =0.3s) to act at the outlet. The traditional method requires 2.5s after the fault occurs for the reclosing switch to act. With the scheme described in the present invention, the power supply can be restored in the shortest time of 0.825s (Δt=0.2s) after the fault, and the longest time is 2.2s.

[0077] If the protection is stage III protection (here t Ⅲ =1s) acts at the outlet, then the reclosing switch needs to act 3s after the fault occurs. By adopting the scheme described in the present invention, the power supply can be restored in 1.2s (Δt=0.2s) after the fault at the shortest and 2.2s at the longest.

[0078] Compared with traditional solutions, the reclosing waiting time can be significantly reduced, which is of great significance to improving power supply reliability.

[0079] In actual engineering applications, the reclosing waiting time can be adjusted according to the actual anti-islanding protection configuration of the distributed power source connected.

[0080] The present invention takes into account the timing coordination of distribution line outlet protection, reclosing and distributed power source anti-islanding protection. On the basis of clarifying the distribution line outlet protection configuration and the bus side voltage before the protection trip, the action time of the distribution line reclosing is automatically adjusted to achieve the timing coordination of the reclosing and distribution line outlet protection and IIDER anti-islanding protection, so as to restore power supply as soon as possible. This method does not require the installation of line-side voltage transformers and can be used in distribution lines that do not have the conditions for voltage-free reclosing. It has good economic efficiency and can provide support for the operation stability and power supply reliability of new power systems.

[0081] Example:

[0082] like Figure 4 The parameters of the active distribution line shown are as follows: the transformer capacity on the power supply side is 40MVA, the short-circuit voltage percentage is US % = 15.5; the impedance per unit length of the line is (0.13 + j0.35) Ω / km, the length of line I is 5 km, the capacity of the load LD1 at the end of this line is 5 MVA, and the load power factor is 0.9; the length of line II is 8 km, and it is divided into two sections by the section circuit breaker QF4. The rated capacities of loads LD2, LD3 and LD4 are 1.3 MVA, 2 MVA and 2.3 MVA respectively, and the load power factor is 0.9; the grid connection point PCC1 of IIDER1 is 1.5 km away from the line outlet, and the grid connection point PCC2 of IIDER2 is 5 km away from the line outlet; the capacities of IIDER1 and IIDER2 are 3 MW and 2 MW respectively. The fault point F1 is set at 0.2 km from the bus A, the fault point F2 is set at 3 km from the bus A, and the fault point F3 is set at 7 km from the bus A. At 0.2s, three-phase instantaneous short circuit faults are set at different fault points. Here, the setting values ​​of each protection switch are shown in Table 1 (the specific protection setting time can be set according to the actual requirements of the project).

[0083] Table 1 Protection switch setting value

[0084]

[0085] Scenario 1: A three-phase short circuit fault occurs at point F1, 0.2 km away from bus point A. The system side and each IIDER inject current into the fault point at the same time.

[0086] The specific process of reclosing is as follows:

[0087] The line outlet protection detects a fault and performs a tripping action. The IIDER connected to the distribution line performs low voltage ride-through according to the low voltage ride-through requirements.

[0088] After the protection trips, the reclosing switch starts, and the reclosing switch control module obtains the bus voltage U1 before tripping and extracts the protection action information. The bus voltage drops to 0.2pu, and the fault current at the protection QF2 exceeds 8kA. The current protection I stage is activated, and Δt is taken as 0.2s. The low voltage ride-through requirement of the IIDER connected to the line has been configured in the reclosing switch control module. According to formula (1), the time required for the connected IIDER anti-islanding protection to act is calculated as ta = 0.625s.

[0089] The reclosing action time is shown in formula (2). According to the extracted protection action information, the reclosing action time is calculated according to formula (2). At this time, the I-stage protection is activated at the outlet, and the outlet protection has no delay, so the reclosing action time is 0.825s. After waiting for 0.825s, the reclosing device is activated, controlling the circuit breaker QF2 to reclose, and the distribution line is restored to power supply. It is 1.375s faster than the traditional reclosing solution.

[0090] When the preset reclosing action time is reached, all IIDERs are disconnected from the grid, the reclosing action is activated, and the output circuit breaker is controlled to reclose.

[0091] Scenario 2: When a three-phase short circuit occurs at the fault point F2, which is 3 km away from A, the system side and each IIDER inject current into the fault point at the same time.

[0092] The specific process of reclosing is as follows:

[0093] The line outlet protection detects a fault and performs a tripping action. The IIDER connected to the distribution line performs low voltage ride-through according to the low voltage ride-through requirements.

[0094] After the protection action trips, the reclosing switch starts, and the reclosing switch control module obtains the bus voltage U1 before tripping and extracts the protection action information. The bus voltage drops to 0.57pu, and the current protection II stage is activated 0.3s after the fault occurs. Δt is taken as 0.2s. The low voltage ride-through requirement of the IIDER connected to the line has been configured in the reclosing switch control module. According to formula (1), the time required for the connected IIDER anti-islanding protection action is calculated as ta = 1.35s.

[0095] The reclosing action time is shown in formula (2). According to the extracted protection action information, the reclosing action time is calculated according to formula (2). At this time, the protection II stage is activated at the exit, and the exit protection action delay is t Ⅱ =0.3s, t Ⅱ <t a , the reclosing action time is t a -t Ⅱ +Δt=1.25s; then, the reclosing device waits for 1.25s after starting and then operates, controlling the circuit breaker QF2 to reclose, and the distribution line resumes power supply. This is 1.25s faster than the traditional reclosing solution.

[0096] When the preset reclosing action time is reached, all IIDERs are disconnected from the grid, the reclosing action is activated, and the output circuit breaker is controlled to reclose.

[0097] The embodiment of the present invention further provides an active power distribution network time-limit adaptive reclosing device, comprising:

[0098] The line export protection module is used to execute the tripping action when the line export protection detects that the distribution line has a fault. The distributed power source IIDER connected to the distribution line performs low voltage ride-through according to the low voltage ride-through requirements;

[0099] The signal acquisition module is used to obtain the bus voltage U before tripping after the tripping action is performed at the line outlet. l , extract line exit protection action information;

[0100] The calculation module is used to calculate the bus voltage U before tripping. l The time t required for the anti-islanding protection of the distributed power source IIDER connected to the line is determined by the low voltage ride-through requirement. a ; According to the staged current protection scheme, the time required for reclosing and anti-islanding protection to operate is t a The timing coordination relationship of the three and the protection action information determine the required preset reclosing action time t r ;

[0101] The reclosing control module is used to execute the reclosing action and control the reclosing of the outlet circuit breaker when the preset reclosing action time arrives and the distributed power source IIDER connected to the line is disconnected from the grid.

[0102] It also includes a configuration module, which is used to configure a staged current protection scheme on the line outlet protection before a fault occurs, and configure the low voltage ride-through requirement of the distributed power source IIDER connected to the line in the reclosing control module.

[0103] The computing module is specifically used for:

[0104] The following formula is used to calculate the time t required for the anti-islanding protection action of the distributed power source IIDER connected to the line: a :

[0105]

[0106] Where U l It is the bus voltage before tripping.

[0107] The calculation module is also used to:

[0108] The timing coordination relationship determination module is specifically used to determine the timing coordination relationship as follows:

[0109]

[0110] Where, t r is the reclosing action time, t a It is the time required for the anti-islanding protection of the distributed power source IIDER connected to the line to take action, and Δt is the fault arc extinction time;

[0111] According to the extracted protection action information, the reclosing action time is calculated according to formula (2):

[0112] If the stage I protection is activated at the outlet, and there is no delay in the outlet protection, the reclosing action time is t r t a +Δt;

[0113] If the stage II protection is activated at the outlet, the outlet protection action delay is t Ⅱ , the reclosing control module is Ⅱ and t a For comparison, if t a >t Ⅱ , reclosing action time t r t a -t Ⅱ +Δt; if t a <t Ⅱ , if the reclosing action time t r is Δt;

[0114] If the stage III protection is activated at the exit, the exit protection action delay is t Ⅲ , the reclosing control module is Ⅲ and t a For comparison, if t a >t Ⅲ , then the reclosing action time t r t a -t Ⅲ +Δt; if t a <t Ⅲ , then the reclosing action time t r is Δt.

[0115] Another embodiment of the present invention provides an active power distribution network time-limit adaptive reclosing control system, comprising: a computer-readable storage medium and a processor;

[0116] The computer-readable storage medium is used to store executable instructions;

[0117] The processor is used to read the executable instructions stored in the computer-readable storage medium to execute the active power distribution network time-limit adaptive reclosing method.

[0118] Another embodiment of the present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which implements the active power distribution network time-limit adaptive reclosing method when executed by a processor.

[0119] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0120] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0121] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0122] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A time-limit adaptive reclosing method for an active distribution network, characterized in that: The following steps are involved: When the line outlet protection detects a fault in the distribution line, it will trip and the distributed power source IIDER connected to the distribution line will perform low voltage ride-through according to the low voltage ride-through requirements; After the line exit performs the tripping action, obtain the bus side voltage U before tripping l , extract line exit protection action information; According to the bus voltage U before tripping l The time t required for the anti-islanding protection of the distributed power source IIDER connected to the line is determined by the low voltage ride-through requirement. a ; According to the staged current protection scheme, the time required for reclosing and anti-islanding protection to operate is t a The timing coordination relationship of the three and the protection action information determine the required preset reclosing action time t r ; When the preset reclosing action time arrives, the distributed power source IIDER connected to the line is disconnected from the grid, and the reclosing action is executed to control the outlet circuit breaker to reclose; According to the staged current protection scheme, the time required for reclosing and anti-islanding protection to operate is t a The timing coordination relationship of the three and the protection action information determine the required preset reclosing action time t r Specifically: Determine the time t required for the staged current protection scheme, reclosing and anti-islanding protection to operate a The timing coordination relationship among the three is: Where, t r is the reclosing action time, t a It is the time required for the anti-islanding protection of the distributed power source IIDER connected to the line to take action, and Δt is the fault arc extinction time; According to the extracted protection action information, the reclosing action time is calculated according to formula (2): If the stage I protection is activated at the outlet, and there is no delay in the outlet protection, the reclosing action time is t r t a +Δt; If the stage II protection is activated at the outlet, the outlet protection action delay is t Ⅱ , the reclosing control module is Ⅱ and t a For comparison, if t a >t Ⅱ , reclosing action time t r t a -t Ⅱ +Δt; if t a <t Ⅱ , if the reclosing action time t r is Δt; If the stage III protection is activated at the exit, the exit protection action delay is t Ⅲ , the reclosing control module is Ⅲ and t a For comparison, if t a >t Ⅲ , then the reclosing action time t r t a -t Ⅲ +Δt; if t a <t Ⅲ , then the reclosing action time t r is Δt.

2. The method for time-limit adaptive reclosing of an active power distribution network according to claim 1, characterized in that: Before a fault occurs, a staged current protection scheme is configured on the line outlet protection, and the low voltage ride-through requirements of the distributed power source IIDER connected to the line are configured in the reclosing control module.

3. The method for time-limit adaptive reclosing of an active power distribution network according to claim 2, characterized in that: The staged current protection scheme is divided into three stages: stage I, stage II, and stage III. The stage I protection action is instantaneous current quick break, and the response time is 0s; the stage II protection action is time-limited current quick break, and the response time is t Ⅱ ; The third stage protection action is time-limited overcurrent protection, and the response time is t Ⅲ .

4. The method for time-limit adaptive reclosing of an active power distribution network according to claim 1, characterized in that: According to the bus voltage U before tripping l The time t required for the anti-islanding protection of the distributed power source IIDER connected to the line is determined by the low voltage ride-through requirement. a Specifically: The following formula is used to calculate the time t required for the anti-islanding protection action of the distributed power source IIDER connected to the line: a : Where U l It is the bus voltage before tripping.

5. The method for time-limit adaptive reclosing of active power distribution network according to claim 4, characterized in that: If there are multiple distributed power sources IIDER connected to the line, the anti-islanding protection action time t of all distributed power sources IIDER is taken a The maximum value of .

6. An active power distribution network time-limit adaptive reclosing device, characterized in that: include: The line export protection module is used to execute the tripping action when the line export protection detects that the distribution line has a fault. The distributed power source IIDER connected to the distribution line performs low voltage ride-through according to the low voltage ride-through requirements; The signal acquisition module is used to obtain the bus voltage U before tripping after the tripping action is performed at the line outlet. l , extract line exit protection action information; The calculation module is used to calculate the bus voltage U before tripping. l The time t required for the anti-islanding protection of the distributed power source IIDER connected to the line is determined by the low voltage ride-through requirement. a ; According to the staged current protection scheme, the time required for reclosing and anti-islanding protection to operate is t a The timing coordination relationship of the three and the protection action information determine the required preset reclosing action time t r ; A reclosing control module, wherein the reclosing control module is used to execute a reclosing action and control the reclosing of the outlet circuit breaker when the preset reclosing action time is reached and the distributed power source IIDER connected to the line is disconnected from the grid; The calculation module is also used to: The timing coordination relationship determination module is specifically used to determine the timing coordination relationship as follows: Where, t r is the reclosing action time, t a It is the time required for the anti-islanding protection of the distributed power source IIDER connected to the line to take action, and Δt is the fault arc extinction time; According to the extracted protection action information, the reclosing action time is calculated according to formula (2): If the stage I protection is activated at the outlet, and there is no delay in the outlet protection, the reclosing action time is t r t a +Δt; If the stage II protection is activated at the outlet, the outlet protection action delay is t Ⅱ , the reclosing control module is Ⅱ and t a For comparison, if t a >t Ⅱ , reclosing action time t r t a -t Ⅱ +Δt; if t a <t Ⅱ , if the reclosing action time t r is Δt; If the stage III protection is activated at the exit, the exit protection action delay is t Ⅲ , the reclosing control module is Ⅲ and t a For comparison, if t a >t Ⅲ , then the reclosing action time t r t a -t Ⅲ +Δt; if t a <t Ⅲ , then the reclosing action time t r is Δt.

7. The active power distribution network time-limit adaptive reclosing device according to claim 6, characterized in that: It also includes a configuration module, which is used to configure a staged current protection scheme on the line outlet protection before a fault occurs, and configure the low voltage ride-through requirement of the distributed power source IIDER connected to the line in the reclosing control module.

8. The active power distribution network time-limit adaptive reclosing device according to claim 6, characterized in that: The computing module is specifically used for: The following formula is used to calculate the time t required for the anti-islanding protection action of the distributed power source IIDER connected to the line: a : Where U l It is the bus voltage before tripping.

9. An active power distribution network time-limit adaptive reclosing control system, comprising: A computer readable storage medium and a processor; The computer-readable storage medium is used to store executable instructions; The processor is used to read the executable instructions stored in the computer-readable storage medium to execute the active distribution network time-limit adaptive reclosing method according to any one of claims 1 to 6.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the active power distribution network time-limit adaptive reclosing method according to any one of claims 1 to 5 is implemented.

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