A method and system for setting relay protection values ​​in distribution network automation terminals

Abstract

This invention relates to the field of relay protection setting technology, and discloses a method and system for setting relay protection settings of distribution network automation terminals. The method involves selecting tie switches in the distribution network, obtaining all distribution network automation switches with remote control functions (remote control, remote monitoring, and remote telemetry) between the 10kV feeder outgoing switch and the tie switch, and combining them to form multiple hierarchical switch pre-selection schemes. The number of user loads and the variance of the number of user loads in each hierarchical switch pre-selection scheme are weighted and calculated. The hierarchical switch pre-selection scheme with the smallest weighted value is selected as the hierarchical switch setting scheme. The overcurrent protection setting time of each hierarchical switch is obtained according to the preset overcurrent protection time margin and the number of hierarchical switches in the hierarchical switch setting scheme. This completes the setting of the overcurrent time setting of the relay protection equipment, thereby solving the problem of relay protection setting mismatch in distribution network automation terminals under emergency conditions and preventing the distribution network automation terminals from malfunctioning due to relay protection setting mismatch under emergency conditions.

Description

Technical Field

[0001] This invention relates to the field of relay protection setting technology, and in particular to a method and system for setting relay protection settings in distribution network automation terminals. Background Technology

[0002] Technical solutions for distribution network self-healing include local voltage-time self-healing schemes, local current-time self-healing schemes, and master station-based differential collaborative self-healing schemes. These schemes are basically based on setting the terminal relay protection settings under a fixed line topology. However, distribution network lines are constantly changing. During the period when the line topology is updated to the new relay protection settings, the relay protection settings of the distribution network automation terminals are actually mismatched, and this process can have a time lag of several days to half a month. Furthermore, during temporary power transfer periods, the relay protection settings do not change, which also leads to a mismatch in the relay protection settings of the distribution network automation terminals.

[0003] Existing technologies generally use static line topology methods to set relay protection settings. However, due to the lack of timeliness, it is difficult to set relay protection settings in emergencies such as temporary power supply transfers. This leads to relay protection setting mismatch problems in distribution network automation terminals under emergency conditions, and malfunctions due to relay protection setting mismatch. Summary of the Invention

[0004] This invention provides a method and system for setting relay protection settings of distribution network automation terminals, which solves the technical problem that in emergency situations such as temporary power transfer, it is difficult to set the relay protection settings due to the lack of timeliness. This leads to the problem that distribution network automation terminals are prone to relay protection setting mismatch in emergency situations, and malfunction due to relay protection setting mismatch.

[0005] In view of this, the first aspect of the present invention provides a method for setting the relay protection setting value of a distribution network automation terminal, comprising the following steps:

[0006] Select a tie switch in the distribution network according to the preset tie switch conditions;

[0007] Obtain all distribution network automation switches with remote control functions between the 10kV feeder outgoing switch and the tie switch in the distribution network, and combine the distribution network automation switches with remote control functions to form multiple hierarchical switch pre-selection schemes.

[0008] Obtain the number of user loads in each pre-selected scheme of the graded switch, calculate the weighted sum of the number of user loads and the variance of the number of user loads, and select the pre-selected scheme of the graded switch with the smallest weighted value from the weighted sum as the graded switch setting scheme.

[0009] Obtain the number of graded switches in the graded switch setting scheme, and obtain the overcurrent protection setting time for each graded switch based on the preset overcurrent protection time margin and the number of graded switches in the graded switch setting scheme.

[0010] Preferably, the preset communication switch conditions include:

[0011] 1) The switch is a distribution network automation switch and is in the open position;

[0012] 2) Both sides of the switch are powered;

[0013] 3) The power supplies on both sides of the switch can be traced back to a certain 10kV feeder outgoing switch according to the real-time line topology connection relationship;

[0014] 4) The switch is activated to enable the three remote functions, which include remote signaling, remote measurement and remote control.

[0015] Preferably, the steps of obtaining the number of user loads in each pre-selected tiered switch scheme, weighting the number of user loads and their variance to obtain a weighted result, and selecting the tiered switch pre-selected scheme with the smallest weighted value from the weighted result as the tiered switch setting scheme specifically include:

[0016] Obtain the number of user loads in each pre-selected scheme for tiered switches, and calculate the number of user loads on the line between every two tiered switches in the pre-selected scheme using the following formula:

[0017]

[0018] In the formula, i is the user serial number, n is the total number of medium-voltage users between the two tiered switches, and A j H represents the number of user loads on the line between the two graded switches. i Let P be the number of low-voltage users for the i-th medium-voltage user. i The median load of the i-th user;

[0019] The number of user loads A on the line between every two tiered switches in the pre-selected tiered switch scheme. j Composition array {A j}, calculate array {A j The variance of};

[0020] Y k =amax{A j}+bW k

[0021] In the formula, Y k For weighted values, a and b are both weight values, max{A j} is an array {A j The largest number in}, W k For variance;

[0022] The pre-selected scheme for the graded switch with the smallest weighted value is selected from the weighted results as the graded switch setting scheme.

[0023] Preferably, the step of obtaining the number of graded switches in the graded switch setting scheme, and obtaining the overcurrent protection setting time of each graded switch based on the preset overcurrent protection time margin and the number of graded switches in the graded switch setting scheme, specifically includes:

[0024] Obtain the number of graded switches in the graded switch setting scheme;

[0025] Divide the preset overcurrent protection time margin by the number of graded switches in the graded switch setting scheme to obtain the corresponding ratio of the overcurrent protection setting time difference for each graded switch.

[0026] Starting from the tie switch, in the feeder switch topology within the station, the overcurrent protection setting time difference is added to the overcurrent I stage time setting of each level of graded switch, and the overcurrent protection setting time difference is added to the I stage time setting of each level of graded switch. Specifically, the initial overcurrent I stage time setting of the first graded switch obtained from the tie switch to the feeder switch topology within the station is 0, and the initial overcurrent II stage time setting of the first graded switch is the overcurrent protection setting time difference. Other non-graded switches are equipped with protection alarms but not protection actions. The overcurrent I stage time of other non-graded switches is set to 0 seconds, and the overcurrent II stage time of other non-graded switches is set to the overcurrent protection setting time difference.

[0027] Preferably, the method further includes:

[0028] The overcurrent stage I and overcurrent stage II constant current values ​​of the graded switch are calculated using the following formulas:

[0029] I L1 =K1×I max

[0030] I L2 =K2×I max

[0031] In the formula, I L1 I is the overcurrent stage set current value of the graded switch. L2 K1 is the overcurrent stage set current value of the graded switch (I1), K2 is the graded switch reliability coefficient, and K2 is the graded switch differential coefficient. max The rated maximum current of the graded switch is given. The overcurrent stage I current setting and overcurrent stage II current setting of other non-graded switches are the same as the overcurrent stage I current setting and overcurrent stage II current setting of the first graded switch downstream of it, respectively.

[0032] Secondly, the present invention provides a distribution network automation terminal relay protection setting system, comprising:

[0033] The tie switch selection module is used to select a tie switch in the distribution network according to preset tie switch conditions.

[0034] The hierarchical switch selection module is used to obtain all distribution network automation switches with remote control functions between the 10kV feeder outgoing switch and the tie switch in the distribution network, and combine the distribution network automation switches with remote control functions to form multiple hierarchical switch pre-selection schemes.

[0035] The setting scheme determination module is used to obtain the number of user loads in each pre-selected scheme of the graded switch, perform weighted calculation on the number of user loads and the variance of the number of user loads to obtain the weighted result, and select the pre-selected scheme of the graded switch with the smallest weight value from the weighted result as the setting scheme of the graded switch.

[0036] The overcurrent time setting module is used to obtain the number of graded switches in the graded switch setting scheme, and to obtain the overcurrent protection setting time of each graded switch according to the preset overcurrent protection time margin and the number of graded switches in the graded switch setting scheme.

[0037] Preferably, the preset communication switch conditions include:

[0038] 1) The switch is a distribution network automation switch and is in the open position;

[0039] 2) Both sides of the switch are powered;

[0040] 3) The power supplies on both sides of the switch can be traced back to a certain 10kV feeder outgoing switch according to the real-time line topology connection relationship;

[0041] 4) The switch is activated to enable the three remote functions, which include remote signaling, remote measurement and remote control.

[0042] Preferably, the graded switch selection module specifically includes:

[0043] The load calculation module is used to obtain the number of user loads in each pre-selected scheme for graded switches. The number of user loads on the line between every two graded switches in the pre-selected scheme is calculated using the following formula:

[0044]

[0045] In the formula, i is the user serial number, n is the total number of medium-voltage users between the two tiered switches, and A j H represents the number of user loads on the line between the two graded switches. i Let P be the number of low-voltage users for the i-th medium-voltage user. i The median load of the i-th user;

[0046] The variance calculation module is used to calculate the number of user loads A on the line between every two tiered switches in the tiered switch pre-selection scheme. j Composition array {A j}, calculate array {A j The variance of};

[0047] Y k =amax{A j}+bW k

[0048] In the formula, Y k For weighted values, a and b are both weight values, max{A j} is an array {A j The largest number in}, W k For variance;

[0049] The scheme selection module is used to select the pre-selected scheme of the graded switch with the smallest weighted value from the weighted results as the graded switch setting scheme.

[0050] Preferably, the overcurrent time tuning module specifically includes:

[0051] The quantity module is used to obtain the number of graded switches in the graded switch setting scheme.

[0052] The time calculation module is used to divide the preset overcurrent protection time margin by the number of graded switches in the graded switch setting scheme to obtain the corresponding ratio of the overcurrent protection setting time difference for each graded switch.

[0053] The time setting module is used to add the overcurrent protection setting time difference to the overcurrent stage I time setting of each level of the feeder switch topology from the tie switch to the substation feeder switch topology. The overcurrent stage II time setting of each level of the feeder switch is added to the overcurrent protection setting time difference on the stage I time setting. Specifically, the initial setting of the overcurrent stage I time of the first level switch obtained from the tie switch to the feeder switch topology in the substation is 0, and the initial setting of the overcurrent stage II time of the first level switch is the overcurrent protection setting time difference. Other non-level switches are activated with protection alarms but not with protection action. The overcurrent stage I time of other non-level switches is set to 0 seconds, and the overcurrent stage II time of other non-level switches is set to the overcurrent protection setting time difference.

[0054] Preferably, the system further includes:

[0055] The current calculation module is used to calculate the overcurrent stage I and overcurrent stage II constant current values ​​of the graded switch using the following formulas:

[0056] I L1 =K1×I max

[0057] I L2 =K2×I max

[0058] In the formula, I L1 I is the overcurrent stage set current value of the graded switch. L2 K1 is the overcurrent stage set current value of the graded switch (I1), K2 is the graded switch reliability coefficient, and K2 is the graded switch differential coefficient. max The rated maximum current of the graded switch is given. The overcurrent stage I current setting and overcurrent stage II current setting of other non-graded switches are the same as the overcurrent stage I current setting and overcurrent stage II current setting of the first graded switch downstream of it, respectively.

[0059] As can be seen from the above technical solutions, the present invention has the following advantages:

[0060] This invention selects tie switches in the distribution network, obtains all distribution automation switches with remote control functions between the 10kV feeder outgoing switch and the tie switch, and combines them to form multiple hierarchical switch pre-selection schemes. The number of user loads and the variance of the number of user loads in each hierarchical switch pre-selection scheme are weighted and calculated. The hierarchical switch pre-selection scheme with the smallest weighted value is selected as the hierarchical switch setting scheme. Based on the preset overcurrent protection time margin and the number of hierarchical switches in the hierarchical switch setting scheme, the overcurrent protection setting time of each hierarchical switch is obtained, thereby completing the setting of the overcurrent time setting of the relay protection equipment without remote modification. This allows for timely setting and execution of the relay protection setting of the distribution automation terminal even in emergencies such as temporary power transfer, solving the problem of relay protection setting mismatch in distribution automation terminals under emergencies and preventing malfunctions of distribution automation terminals due to relay protection setting mismatch under emergencies. Attached Figure Description

[0061] Figure 1 A flowchart of a method for setting the relay protection value of a distribution network automation terminal provided in an embodiment of the present invention;

[0062] Figure 2 This is a schematic diagram of a feeder circuit for a power distribution network provided in an embodiment of the present invention;

[0063] Figure 3 This is a schematic diagram of a distribution network automation terminal relay protection setting system provided in an embodiment of the present invention. Detailed Implementation

[0064] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0065] For easier understanding, please refer to Figure 1 The present invention provides a method for setting the relay protection setting value of a distribution network automation terminal, comprising the following steps:

[0066] S1. Select a tie switch in the distribution network according to the preset tie switch conditions.

[0067] The preset communication switch conditions include:

[0068] 1) The switch is a distribution network automation switch and is in the open position;

[0069] 2) Both sides of the switch are powered;

[0070] 3) The power supplies on both sides of the switch can be traced back to a certain 10kV feeder outgoing switch according to the real-time line topology connection relationship;

[0071] 4) Switch on to enable the three remote functions, which include remote signaling, remote measurement and remote control.

[0072] S2. Obtain all distribution network automation switches with remote control functions between the 10kV feeder outgoing switch and the tie switch in the distribution network, and combine the distribution network automation switches with remote control functions to form multiple hierarchical switch pre-selection schemes.

[0073] In one example, there can be a maximum of two graded switches between the 10kV feeder outgoing switch and the tie switch. Starting from the outgoing switch, the first graded switch is called the first graded switch, and the second graded switch is called the second graded switch.

[0074] For distribution network automation switches selected other than the graded switches, protection alarms are activated, but protection actions are not performed. The current setting is consistent with the first graded switch downstream, and the time setting is 0 seconds.

[0075] S3. Obtain the number of user loads in each pre-selected scheme of the graded switch, calculate the weighted average of the number of user loads and the variance of the number of user loads, and select the pre-selected scheme of the graded switch with the smallest weighted value from the weighted average results as the graded switch setting scheme.

[0076] S4. Obtain the number of graded switches in the graded switch setting scheme, and obtain the overcurrent protection setting time of each graded switch according to the preset overcurrent protection time margin and the number of graded switches in the graded switch setting scheme.

[0077] The system automatically and remotely modifies the relay protection settings of each distribution network automation switch. If the relay protection settings of some distribution network automation switches fail to be modified or cannot be modified remotely, regardless of whether they are dynamic tie switches or hierarchical switches, the switches whose relay protection settings cannot be modified are removed, tie switches and hierarchical switches are re-determined, and relay protection settings are set and modified accordingly.

[0078] It should be noted that this embodiment provides a method for setting the relay protection setting of a distribution network automation terminal. By selecting tie switches in the distribution network, all distribution network automation switches with remote control functions between the 10kV feeder outgoing switch and the tie switch in the distribution network are obtained and combined to form multiple hierarchical switch pre-selection schemes. The number of user loads and the variance of the number of user loads in each hierarchical switch pre-selection scheme are weighted and calculated. The hierarchical switch pre-selection scheme with the smallest weighted value is selected as the hierarchical switch setting scheme. The overcurrent protection setting time of each hierarchical switch is obtained according to the preset overcurrent protection time margin and the number of hierarchical switches in the hierarchical switch setting scheme. Thus, the overcurrent time setting of the relay protection equipment is set without remote modification. Therefore, even in the event of a sudden situation such as temporary power transfer, the relay protection setting of the distribution network automation terminal can be set and executed in a timely manner, solving the problem of relay protection setting mismatch in the distribution network automation terminal under the sudden situation and preventing the distribution network automation terminal from malfunctioning due to relay protection setting mismatch under the sudden situation.

[0079] In one specific embodiment, step S3 specifically includes:

[0080] S301. Obtain the number of user loads in each pre-selected scheme for graded switches, and calculate the number of user loads on the line between every two graded switches using the following formula:

[0081]

[0082] In the formula, i is the user serial number, n is the total number of medium-voltage users between the two tiered switches, and A j H represents the number of user loads on the line between the two graded switches. i Let P be the number of low-voltage users for the i-th medium-voltage user. i The median load of the i-th user;

[0083] S302, the number of user loads A on the line between every two graded switches in the graded switch pre-selection scheme. j Composition array {A j}, calculate array {A jThe variance of};

[0084] Y k =amax{A j}+bW k

[0085] In the formula, Y k For weighted values, a and b are both weight values, max{A j} is an array {A j The largest number in}, W k For variance;

[0086] S303. Select the pre-selected scheme of the graded switch with the smallest weighted value from the weighted results as the graded switch setting scheme.

[0087] It should be noted that the smaller the variance of the number of user loads, the more uniform the user load is. At the same time, the smaller the number of user loads, the fewer user loads are involved, and the smaller the impact, thereby enhancing the stability of the power grid operation.

[0088] In one specific embodiment, step S4 specifically includes:

[0089] S401. Obtain the number of graded switches in the graded switch setting scheme;

[0090] S402. Divide the preset overcurrent protection time margin by the number of graded switches in the graded switch setting scheme to obtain the corresponding ratio of the overcurrent protection setting time difference for each graded switch.

[0091] Starting from the tie switch, in the feeder switch topology within the station, the overcurrent protection setting time difference is added to the overcurrent I stage time setting of each level of graded switch, and the overcurrent protection setting time difference is added to the I stage time setting of each level of graded switch. Specifically, the initial overcurrent I stage time setting of the first graded switch obtained from the tie switch to the feeder switch topology within the station is 0, and the initial overcurrent II stage time setting of the first graded switch is the overcurrent protection setting time difference. Other non-graded switches are equipped with protection alarms but not protection actions. The overcurrent I stage time of other non-graded switches is set to 0 seconds, and the overcurrent II stage time of other non-graded switches is set to the overcurrent protection setting time difference.

[0092] In one specific embodiment, the method further includes:

[0093] The overcurrent stage I and overcurrent stage II constant current values ​​of the graded switch are calculated using the following formulas:

[0094] I L1 =K1×I max

[0095] I L2=K2×I max

[0096] In the formula, I L1 I is the overcurrent stage set current value of the graded switch. L2 K1 is the overcurrent stage set current value of the graded switch (I1), K2 is the graded switch reliability coefficient, and K2 is the graded switch differential coefficient. max The rated maximum current of the graded switch is given. The overcurrent stage I current setting and overcurrent stage II current setting of other non-graded switches are the same as the overcurrent stage I current setting and overcurrent stage II current setting of the first graded switch downstream of it, respectively.

[0097] like Figure 2 The diagram illustrates the feeder circuit of a distribution network. In the diagram, switches F13, Z12, Z62, F4, and F9 are first-level switches; switches F12, Z61, Z11, F2, and F7 are second-level switches; switches Z13 and F6 are in the open position (in this case, they will be considered as tie switches under normal operating conditions); substation 10kV feeder switches K1, F1, F3, F5, F10, K2, Z41, Z51, Z71, F14, F15, F11, and K3 are in the closed position; switches ZXX are branch switches; KX is a substation feeder switch; and the remaining FX switches are ordinary level switches. All switches outside the substation are distribution network automation switches.

[0098] Feeder 1 and Feeder 2 are connected via F6, and Feeder 1 and Feeder 3 are connected via Z13. For Feeder 2, A1 is the number of user loads between F7 and K2, A2 is the number of user loads between F9 and F7, and A3 is the number of user loads between F6 and F9.

[0099] If multiple tie switches can be connected from the 10kV feeder outgoing switch, there are multiple connection paths. There can be multiple first-level switches or multiple second-level switches. The determination of the first-level switches and second-level switches follows the aforementioned five points. However, the following principle is added:

[0100] The method for determining the first segment of users is changed to: all users between the 10kV feeder outgoing switch and each of the second-level switches belong to the first segment of users, of which the number of low-voltage users is A1; the method for determining the second segment of users of a certain path i is: all users between its second-level switch and each of its downstream first-level switches belong to the second segment of users of a certain path i, of which the number of low-voltage user loads is A2i; the method for determining the third segment of users of a certain sub-path j under a certain path i is: all users between its first-level switch and the tie switch belong to the third segment of users of a certain sub-path j under a certain path i, of which the number of low-voltage user loads is A3ij.

[0101] Iterate through the distribution network automation switches as the first and second level switches, calculate the variance of the user load sample composed of A1, A2i, and A3ij for each time, select the case with the smallest variance of user load and the smallest number of user loads to determine the location of the first and second level switches, and use it as the level switch setting scheme, with a quantity of 2, and an overcurrent protection time margin of 0.3 seconds, so the overcurrent protection setting time of each level switch is 0.15 seconds.

[0102] The above is a detailed description of an embodiment of a method for setting the relay protection value of a distribution network automation terminal provided by the present invention. The following is a detailed description of an embodiment of a system for setting the relay protection value of a distribution network automation terminal provided by the present invention.

[0103] For easier understanding, please refer to Figure 3 This invention provides a power distribution network automation terminal relay protection setting system, comprising:

[0104] The tie switch selection module 100 is used to select a tie switch in the distribution network according to preset tie switch conditions.

[0105] The hierarchical switch selection module 200 is used to obtain all the distribution network automation switches with remote control functions between the 10kV feeder outgoing switch and the tie switch in the distribution network, and to combine the distribution network automation switches with remote control functions to form multiple hierarchical switch pre-selection schemes.

[0106] The setting scheme determination module 300 is used to obtain the number of user loads in each pre-selected scheme of the graded switch, calculate the weighted sum of the number of user loads and the variance of the number of user loads, obtain the weighted result, and select the pre-selected scheme of the graded switch with the smallest weighted value from the weighted result as the setting scheme of the graded switch.

[0107] The overcurrent time setting module 400 is used to obtain the number of graded switches in the graded switch setting scheme, and to obtain the overcurrent protection setting time of each graded switch according to the preset overcurrent protection time margin and the number of graded switches in the graded switch setting scheme.

[0108] In one specific embodiment, the preset communication switch conditions include:

[0109] 1) The switch is a distribution network automation switch and is in the open position;

[0110] 2) Both sides of the switch are powered;

[0111] 3) The power supplies on both sides of the switch can be traced back to a certain 10kV feeder outgoing switch according to the real-time line topology connection relationship;

[0112] 4) Switch on to enable the three remote functions, which include remote signaling, remote measurement and remote control.

[0113] In one specific embodiment, the graded switch selection module specifically includes:

[0114] The load calculation module is used to obtain the number of user loads in each pre-selected scheme for graded switches. The number of user loads on the line between every two graded switches in the pre-selected scheme is calculated using the following formula:

[0115]

[0116] In the formula, i is the user serial number, n is the total number of medium-voltage users between the two tiered switches, and A j H represents the number of user loads on the line between the two graded switches. i Let P be the number of low-voltage users for the i-th medium-voltage user. i The median load of the i-th user;

[0117] The variance calculation module is used to calculate the number of user loads A on the line between every two tiered switches in the tiered switch pre-selection scheme. j Composition array {A j}, calculate array {A j The variance of};

[0118] Y k =amax{A j}+bW k

[0119] In the formula, Y k For weighted values, a and b are both weight values, max{A j} is an array {A j The largest number in}, W k For variance;

[0120] The scheme selection module is used to select the pre-selected scheme of the graded switch with the smallest weighted value from the weighted results as the graded switch setting scheme.

[0121] In one specific embodiment, the overcurrent time tuning module specifically includes:

[0122] The quantity module is used to obtain the number of graded switches in the graded switch setting scheme.

[0123] The time calculation module is used to divide the preset overcurrent protection time margin by the number of graded switches in the graded switch setting scheme to obtain the corresponding ratio of the overcurrent protection setting time difference for each graded switch.

[0124] The time setting module is used to add the overcurrent protection setting time difference to the overcurrent stage I time setting of each level of the feeder switch topology from the tie switch to the substation feeder switch topology. The overcurrent stage II time setting of each level of the feeder switch is added to the overcurrent protection setting time difference on the stage I time setting. Specifically, the initial setting of the overcurrent stage I time of the first level switch obtained from the tie switch to the feeder switch topology in the substation is 0, and the initial setting of the overcurrent stage II time of the first level switch is the overcurrent protection setting time difference. Other non-level switches are activated with protection alarms but not with protection action. The overcurrent stage I time of other non-level switches is set to 0 seconds, and the overcurrent stage II time of other non-level switches is set to the overcurrent protection setting time difference.

[0125] In one specific embodiment, the system further includes:

[0126] The overcurrent stage I and overcurrent stage II constant current values ​​of the graded switch are calculated using the following formulas:

[0127] I L1 =K1×I max

[0128] I L2 =K2×I max

[0129] In the formula, I L1 I is the overcurrent stage set current value of the graded switch. L2 K1 is the overcurrent stage set current value of the graded switch (I1), K2 is the graded switch reliability coefficient, and K2 is the graded switch differential coefficient. max The rated maximum current of the graded switch is given. The overcurrent stage I current setting and overcurrent stage II current setting of other non-graded switches are the same as the overcurrent stage I current setting and overcurrent stage II current setting of the first graded switch downstream of it, respectively.

[0130] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0131] In the several embodiments provided by this invention, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0132] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0133] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0134] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for setting the relay protection setting value of a distribution network automation terminal, characterized in that, Includes the following steps: Select a tie switch in the distribution network according to the preset tie switch conditions; Obtain all distribution network automation switches with remote control functions between the 10kV feeder outgoing switch and the tie switch in the distribution network, and combine the distribution network automation switches with remote control functions to form multiple hierarchical switch pre-selection schemes. Obtain the number of user loads in each pre-selected scheme of the graded switch, calculate the weighted sum of the number of user loads and the variance of the number of user loads, and select the pre-selected scheme of the graded switch with the smallest weighted value from the weighted sum as the graded switch setting scheme. Obtain the number of graded switches in the graded switch setting scheme, and obtain the overcurrent protection setting time for each graded switch based on the preset overcurrent protection time margin and the number of graded switches in the graded switch setting scheme.

2. The method for setting the relay protection setting value of a distribution network automation terminal according to claim 1, characterized in that, The preset communication switch conditions include: 1) The switch is a distribution network automation switch and is in the open position; 2) Both sides of the switch are powered; 3) The power supplies on both sides of the switch can be traced back to a certain 10kV feeder outgoing switch according to the real-time line topology connection relationship; 4) The switch is activated to enable the three remote functions, which include remote signaling, remote measurement and remote control.

3. The method for setting the relay protection setting value of a distribution network automation terminal according to claim 1, characterized in that, The steps of obtaining the number of user loads in each pre-selected tiered switch scheme, weighting the number of user loads and their variance to obtain a weighted result, and selecting the tiered switch pre-selected scheme with the smallest weighted value from the weighted result as the tiered switch setting scheme specifically include: Obtain the number of user loads in each pre-selected scheme for tiered switches, and calculate the number of user loads on the line between every two tiered switches in the pre-selected scheme using the following formula: In the formula, i is the user serial number, n is the total number of medium-voltage users between the two tiered switches, and A j H represents the number of user loads on the line between the two graded switches. i Let P be the number of low-voltage users for the i-th medium-voltage user. i The median load of the i-th user; The number of user loads A on the line between every two tiered switches in the pre-selected tiered switch scheme. j Composition array {A j }, calculate array {A j The variance of}; Y k =amax{A j }+bW k In the formula, Y k For weighted values, a and b are both weight values, max{A j } is an array {A j The largest number in}, W k For variance; The pre-selected scheme for the graded switch with the smallest weighted value is selected from the weighted results as the graded switch setting scheme.

4. The method for setting the relay protection setting value of a distribution network automation terminal according to claim 3, characterized in that, The steps of obtaining the number of graded switches in the graded switch setting scheme, and obtaining the overcurrent protection setting time of each graded switch based on the preset overcurrent protection time margin and the number of graded switches in the graded switch setting scheme, specifically include: Obtain the number of graded switches in the graded switch setting scheme; Divide the preset overcurrent protection time margin by the number of graded switches in the graded switch setting scheme to obtain the corresponding ratio of the overcurrent protection setting time difference for each graded switch. Starting from the tie switch, in the feeder switch topology within the station, the overcurrent protection setting time difference is added to the overcurrent I stage time setting of each level of graded switch, and the overcurrent protection setting time difference is added to the I stage time setting of each level of graded switch. Specifically, the initial overcurrent I stage time setting of the first graded switch obtained from the tie switch to the feeder switch topology within the station is 0, and the initial overcurrent II stage time setting of the first graded switch is the overcurrent protection setting time difference. Other non-graded switches are equipped with protection alarms but not protection actions. The overcurrent I stage time of other non-graded switches is set to 0 seconds, and the overcurrent II stage time of other non-graded switches is set to the overcurrent protection setting time difference.

5. The method for setting the relay protection setting value of a distribution network automation terminal according to claim 1, characterized in that, Also includes: The overcurrent stage I and overcurrent stage II constant current values ​​of the graded switch are calculated using the following formulas: I L1 =K1×I max I L2 =K2×I max In the formula, I L1 I is the overcurrent stage set current value of the graded switch. L2 K1 is the overcurrent stage set current value of the graded switch (I1), K2 is the graded switch reliability coefficient, and K2 is the graded switch differential coefficient. max The rated maximum current of the graded switch is given. The overcurrent stage I current setting and overcurrent stage II current setting of other non-graded switches are the same as the overcurrent stage I current setting and overcurrent stage II current setting of the first graded switch downstream of it, respectively.

6. A system for setting relay protection settings in a distribution network automation terminal, characterized in that, include: The tie switch selection module is used to select a tie switch in the distribution network according to preset tie switch conditions. The hierarchical switch selection module is used to obtain all distribution network automation switches with remote control functions between the 10kV feeder outgoing switch and the tie switch in the distribution network, and combine the distribution network automation switches with remote control functions to form multiple hierarchical switch pre-selection schemes. The setting scheme determination module is used to obtain the number of user loads in each pre-selected scheme of the graded switch, perform weighted calculation on the number of user loads and the variance of the number of user loads to obtain the weighted result, and select the pre-selected scheme of the graded switch with the smallest weight value from the weighted result as the setting scheme of the graded switch. The overcurrent time setting module is used to obtain the number of graded switches in the graded switch setting scheme, and to obtain the overcurrent protection setting time of each graded switch according to the preset overcurrent protection time margin and the number of graded switches in the graded switch setting scheme.

7. The distribution network automation terminal relay protection setting system according to claim 6, characterized in that, The preset communication switch conditions include: 1) The switch is a distribution network automation switch and is in the open position; 2) Both sides of the switch are powered; 3) The power supplies on both sides of the switch can be traced back to a certain 10kV feeder outgoing switch according to the real-time line topology connection relationship; 4) The switch is activated to enable the three remote functions, which include remote signaling, remote measurement and remote control.

8. The distribution network automation terminal relay protection setting system according to claim 6, characterized in that, The graded switch selection module specifically includes: The load calculation module is used to obtain the number of user loads in each pre-selected scheme for graded switches. The number of user loads on the line between every two graded switches in the pre-selected scheme is calculated using the following formula: In the formula, i is the user serial number, n is the total number of medium-voltage users between the two tiered switches, and A j H represents the number of user loads on the line between the two graded switches. i Let P be the number of low-voltage users for the i-th medium-voltage user. i The median load of the i-th user; The variance calculation module is used to calculate the number of user loads A on the line between every two tiered switches in the tiered switch pre-selection scheme. j Composition array {A j }, calculate array {A j The variance of}; Y k =amax{A j }+bW k In the formula, Y k For weighted values, a and b are both weight values, max{A j } is an array {A j The largest number in}, W k For variance; The scheme selection module is used to select the pre-selected scheme of the graded switch with the smallest weighted value from the weighted results as the graded switch setting scheme.

9. The distribution network automation terminal relay protection setting system according to claim 8, characterized in that, The overcurrent time tuning module specifically includes: The quantity module is used to obtain the number of graded switches in the graded switch setting scheme. The time calculation module is used to divide the preset overcurrent protection time margin by the number of graded switches in the graded switch setting scheme to obtain the corresponding ratio of the overcurrent protection setting time difference for each graded switch. The time setting module is used to add the overcurrent protection setting time difference to the overcurrent stage I time setting of each level of the feeder switch topology from the tie switch to the substation feeder switch topology. The overcurrent stage II time setting of each level of the feeder switch is added to the overcurrent protection setting time difference on the stage I time setting. Specifically, the initial setting of the overcurrent stage I time of the first level switch obtained from the tie switch to the feeder switch topology in the substation is 0, and the initial setting of the overcurrent stage II time of the first level switch is the overcurrent protection setting time difference. Other non-level switches are activated with protection alarms but not with protection action. The overcurrent stage I time of other non-level switches is set to 0 seconds, and the overcurrent stage II time of other non-level switches is set to the overcurrent protection setting time difference.

10. The distribution network automation terminal relay protection setting system according to claim 6, characterized in that, Also includes: The current calculation module is used to calculate the overcurrent stage I and overcurrent stage II constant current values ​​of the graded switch using the following formulas: I L1 =K1×I max I L2 =K2×I max In the formula, I L1 I is the overcurrent stage set current value of the graded switch. L2 K1 is the overcurrent stage set current value of the graded switch (I1), K2 is the graded switch reliability coefficient, and K2 is the graded switch differential coefficient. max The rated maximum current of the graded switch is given. The overcurrent stage I current setting and overcurrent stage II current setting of other non-graded switches are the same as the overcurrent stage I current setting and overcurrent stage II current setting of the first graded switch downstream of it, respectively.

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