A 35kV box-type transformer low-voltage side circuit breaker protection method

Abstract

The application relates to the technical field of box-type transformers, in particular to a 35kV box-type transformer low-voltage side circuit breaker protection method. The method comprises the following steps: generating a historical evaluation value according to equipment parameters and historical operation parameters, and constructing multiple adjustment cycles according to the historical evaluation value; sequentially setting a primary protection strategy in each adjustment cycle; obtaining operation parameters of the circuit breaker according to a preset feedback time node, and judging whether to generate a maintenance instruction. According to the operation parameters of the circuit breaker, multiple characteristic indexes are set, and an operation simulation model is established to generate an expected change curve of each characteristic index, so that the state of the circuit breaker in each adjustment cycle is predicted, the corresponding primary protection strategy is dynamically adjusted, the misoperation risk of the circuit breaker is reduced, and the safe operation of the transformer is ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of box-type transformers, in particular to a 35kV box-type transformer low-voltage side circuit breaker protection method. BACKGROUND

[0002] When the transformer is closed or reclosed, a magnetizing inrush current will be generated, which is a transient current with a value much larger than the rated current of the transformer. If the magnetizing inrush current is too high, it may exceed the setting value of the relay protection device, causing the protection device to malfunction. This is because the relay protection device is usually set according to the rated current and voltage change rate of the transformer, and when the magnetizing inrush current is too large, the protection device may mistakenly think that there is a fault inside the transformer, and quickly disconnect the low-voltage side circuit breaker, causing the transformer to shut down.

[0003] Circuit breaker malfunction will cause the transformer to shut down, affecting the stable operation of the entire power system, and even possibly leading to a large-scale power outage accident. SUMMARY

[0004] The purpose of the present application is to solve the above technical problems, and the present application provides a 35kV box-type transformer low-voltage side circuit breaker protection method, which aims to reduce the risk of circuit breaker malfunction and ensure the safe operation of the transformer.

[0005] In some embodiments of the present application, according to the operating parameters of the circuit breaker, a plurality of characteristic indexes are set, and by establishing an operating simulation model, the expected variation curve of each characteristic index is generated, thereby predicting the state of the circuit breaker in each adjustment period, dynamically adjusting the corresponding primary protection strategy, reducing the risk of circuit breaker malfunction, and ensuring the safe operation of the transformer.

[0006] In some embodiments of the present application, by setting the primary protection strategy in each adjustment period, the action time under each current threshold is generated, a gradient selection mechanism is constructed, the malfunction of the circuit breaker caused by transient magnetizing inrush current is avoided, the needs of the equipment are met, and the safe operation of the transformer is ensured.

[0007] In some embodiments of the present application, a 35kV box-type transformer low-voltage side circuit breaker protection method is provided, which includes:

[0008] Generating a historical evaluation value according to the device parameters and historical operating parameters, and constructing a plurality of adjustment periods according to the historical evaluation value;

[0009] Setting the primary protection strategy in each adjustment period in turn;

[0010] Obtaining the operating parameters of the circuit breaker according to the preset feedback time node, and determining whether to generate a maintenance instruction.

[0011] In some embodiments of the present application, when a plurality of adjustment periods are constructed, the following steps are included:

[0012] generating a historical evaluation value p;

[0013] p = e1*Q1* β 1i *ji + e2*Q2* β 2i *ki];

[0014] wherein e1 is a preset first weight coefficient; e2 is a preset second weight coefficient; Q1 is a preset first fixed coefficient; Q2 is a preset second fixed coefficient; is the number of device evaluation indexes; β 1i is the influence factor of the i-th device evaluation index; ji is the reference value of the i-th device evaluation index; 2 is the number of operation evaluation indexes; β 2i is the influence factor of the i-th operation evaluation index; ki is the reference value of the i-th operation evaluation index;

[0015] setting the duration t of a single adjustment period according to the historical evaluation value p;

[0016] establishing an adjustment period sequence A based on the time sequence and the duration t of the single adjustment period, A = (a1, a2…ai…an), wherein ai is the i-th adjustment period set based on the time sequence; and n is the number of adjustment periods.

[0017] In some embodiments of the present application, when the first-level protection strategy in each adjustment period is sequentially set, the following steps are included:

[0018] setting a plurality of characteristic indexes and an operation simulation model according to historical operation parameters;

[0019] generating initial reference values of the characteristic indexes;

[0020] constructing an initial protection strategy according to the initial reference values of the characteristic indexes, wherein the initial protection strategy includes a plurality of current fixed values and action durations corresponding to each current fixed value;

[0021] sequentially setting ai as a target adjustment period according to the adjustment period sequence A;

[0022] generating expected reference values of the characteristic indexes at a starting time node of the target adjustment period according to the operation simulation model;

[0023] judging whether to generate an adjustment instruction according to all the expected reference values, and generating a first-level protection strategy in the target adjustment period;

[0024] sequentially generating first-level protection strategies in each adjustment period;

[0025] A first protection strategy sequence B is established, B=(b1, b2…bi…bn), wherein bi is a first protection strategy in the i th adjustment period.

[0026] In some embodiments of the present application, when the adjustment instruction is generated according to all expected reference values, the following steps are included:

[0027] A variation evaluation value f is generated according to all expected reference values.

[0028] f= βi*(c i -c' i ) 2 ;

[0029] Wherein θ is the number of characteristic indexes, c i is the expected reference value of the i th characteristic index at the starting time node of the target adjustment period; βi is the influence factor of the i th characteristic index, c' i is the initial reference value of the i th characteristic index.

[0030] A first variation evaluation value threshold F1 is preset.

[0031] If f<F1, no adjustment instruction is generated, and the initial protection strategy is set as the first protection strategy of the target adjustment period.

[0032] If f>F1, a first adjustment instruction is generated, the initial protection strategy is revised according to the first adjustment instruction, and the first protection strategy of the target adjustment period is generated according to the revision result.

[0033] In some embodiments of the present application, when it is determined whether to generate a maintenance instruction, the following steps are included:

[0034] The operation parameter of the current feedback time node is obtained, and a risk evaluation value g of the current feedback time node is generated according to the operation parameter.

[0035] A first risk evaluation value threshold G1 and a second risk evaluation value threshold G2 are preset.

[0036] If g<G1, no maintenance instruction is generated at the current feedback time node.

[0037] If G1≤g<G2, a fluctuation evaluation value d of the current feedback time node is generated, and it is determined whether to generate a maintenance instruction at the current feedback time node according to the fluctuation evaluation value d.

[0038] If g>G2, a first maintenance instruction is generated at the current feedback time node.

[0039] In some embodiments of the present application, when the risk evaluation value g of the current feedback time node is generated, the following steps are included:

[0040] g=e3*Q3*[ (e3*ri*ci)+e4*Q4*Y;

[0041] Wherein, e3 is a preset third weight coefficient; e4 is a preset third weight coefficient; Q3 is a preset third fixed coefficient; Q4 is a preset fourth fixed coefficient; u is the number of risk evaluation indexes; ri is the influence factor of the i th risk evaluation index; ci is the reference value of the i th risk evaluation index at the current feedback time node; Y is the set first reference value of the operating parameter in the last adjustment period based on the corresponding adjustment period of the current feedback time node.

[0042] In some embodiments of the application, when the fluctuation evaluation value d of the current feedback time node is generated, it includes:

[0043] Generating the actual reference value of each feature index at the current feedback time node;

[0044] Generating the fluctuation evaluation value d of the current feedback time node according to all actual reference values;

[0045] Presetting a first fluctuation evaluation value threshold D1 and a second fluctuation evaluation value threshold D2;

[0046] If d < D1, the current feedback time node does not generate a first maintenance instruction;

[0047] When D1 ≤ d < D2, a first correction instruction is generated, and a compensation coefficient m is set according to the first correction instruction;

[0048] If m * g > G1, the current feedback time node generates a first maintenance instruction; if m * g < G1, the current feedback time node does not generate a maintenance instruction;

[0049] If d > D2, the current feedback time node generates a second correction instruction and a first maintenance instruction.

[0050] In some embodiments of the application, the fluctuation evaluation value d of the current feedback time node includes:

[0051] d = e5*Q5*[ βi*(c 1i -c' i ) 2 ]+e6*Q6*[ βi*(c 1i -c 2i ) 2 ]

[0052] Wherein, e5 is a preset fifth weight coefficient, e6 is a preset sixth weight coefficient; Q5 is a preset fifth fixed coefficient; Q6 is a preset sixth fixed coefficient; c 1iis the reference value of the i-th characteristic evaluation index at the current feedback time node; θ is the number of characteristic indexes; βi is the influence factor of the i-th characteristic index; c i is the initial reference value of the i-th characteristic index; c 2i is the expected reference value of the i-th characteristic index at the starting time node of the adjustment period corresponding to the current feedback time node.

[0053] In some embodiments of the present application, when the compensation coefficient m is set according to the first correction instruction, it includes:

[0054] The first fluctuation evaluation value interval (D3, D4), the second fluctuation evaluation value interval (D4, D5), and the third fluctuation evaluation value interval (D5, D6) are preset.

[0055] The fluctuation evaluation value d of the current feedback time node is obtained.

[0056] If the fluctuation evaluation value d is in the preset first fluctuation evaluation value interval, the compensation coefficient m is set as the preset first compensation coefficient m1, that is, m = m1.

[0057] If the fluctuation evaluation value d is in the preset second fluctuation evaluation value interval, the compensation coefficient m is set as the preset second compensation coefficient m2, that is, m = m2.

[0058] If the fluctuation evaluation value d is in the preset third fluctuation evaluation value interval, the compensation coefficient m is set as the preset third compensation coefficient m3, that is, m = m3; and m3 < m2 < m1 < 1.

[0059] Compared with the prior art, the 35kV box-type transformer low-voltage side circuit breaker protection method of the embodiment of the present application has the beneficial effects that:

[0060] According to the operating parameters of the circuit breaker, a plurality of characteristic indexes are set, and by establishing an operating simulation model, an expected variation curve of each characteristic index is generated, thereby predicting the state of the circuit breaker in each adjustment period, dynamically adjusting the corresponding first protection strategy, reducing the misoperation risk of the circuit breaker, and ensuring the safe operation of the transformer.

[0061] By setting the first protection strategy in each adjustment period, the action time under each current threshold is generated, a gradient selection mechanism is constructed, the misoperation of the circuit breaker caused by transient excitation inrush current is avoided, the needs of the equipment are met, and the safe operation of the transformer is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 is a flowchart of a 35kV box-type transformer low-voltage side circuit breaker protection method in the preferred embodiment of the present application. DETAILED DESCRIPTION

[0063] The specific embodiments of the present application will be further described in conjunction with the drawings and examples. The following examples are used to illustrate the present application, but not to limit the scope of the present application.

[0064] In the description of the present application, it needs to be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0065] The terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0066] In the description of the present application, it needs to be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0067] As Figure 1 shown, the low-voltage side circuit breaker protection method of the 35kV box-type transformer of the preferred embodiment of the present application comprises:

[0068] S101: generating a historical evaluation value according to the equipment parameters and historical operation parameters, and constructing a plurality of adjustment periods according to the historical evaluation value;

[0069] S102: setting a primary protection strategy in each adjustment period in turn;

[0070] S103: obtaining the operation parameters of the circuit breaker according to the preset feedback time node, and determining whether to generate a maintenance instruction.

[0071] Specifically, the primary protection strategy includes a plurality of current thresholds and the required action time of each current threshold. Through the gradient selection mechanism, the misoperation of the circuit breaker caused by transient excitation inrush current is avoided, at the same time, the needs of the equipment are met, and the safe operation of the transformer is ensured.

[0072] Specifically, when the plurality of adjustment periods are constructed, the following is included:

[0073] generating a historical evaluation value p;

[0074] p = e1*Q1* β 1i *ji] + e2*Q2* β 2i *ki];

[0075] wherein e1 is a preset first weight coefficient; e2 is a preset second weight coefficient; Q1 is a preset first fixed coefficient; Q2 is a preset second fixed coefficient; is the number of device evaluation indexes; β 1i is an influence factor of the i-th device evaluation index; ji is a reference value of the i-th device evaluation index; 2 is the number of operation evaluation indexes; β 2i is an influence factor of the i-th operation evaluation index; ki is a reference value of the i-th operation evaluation index;

[0076] setting the length t of a single adjustment period according to the historical evaluation value p;

[0077] establishing an adjustment period sequence A, A = (a1, a2…ai…an) based on the time sequence and the length t of the single adjustment period, wherein ai is the i-th adjustment period set based on the time sequence; and n is the number of adjustment periods.

[0078] Specifically, by presetting the first fixed coefficient and the second fixed coefficient, all parameters in the model are normalized, so that each parameter is within the same value range.

[0079] Specifically, the device evaluation indexes include device life, device structure, number of parallel transformers, installation node of circuit breakers, and other parameters that have an impact on abnormal current; the operation evaluation indexes include historical misoperation frequency, fault frequency, fault category, and other parameters.

[0080] Specifically, the greater the historical evaluation value is, the greater the possibility of misoperation risk of the current circuit breaker is, and the greater the possibility of operation fluctuation of the corresponding transformer is, so the length of the single adjustment period needs to be reduced, and the precision of the primary protection strategy needs to be improved to protect the operation of the transformer.

[0081] In the preferred embodiment of the present application, when the primary protection strategy in each adjustment period is set in turn, the following is included:

[0082] setting a plurality of characteristic indexes and an operation simulation model according to historical operation parameters;

[0083] generating initial reference values of the plurality of characteristic indexes;

[0084] An initial protection strategy is constructed according to the initial reference value of the characteristic index, and the initial protection strategy includes multiple current fixed values and action time lengths corresponding to the current fixed values;

[0085] ai is set as a target adjustment period according to the adjustment period sequence A in turn;

[0086] The expected reference value of each characteristic index at the starting time node of the target adjustment period is generated according to the running simulation model;

[0087] Whether to generate an adjustment instruction is judged according to all the expected reference values, and a primary protection strategy in the target adjustment period is generated;

[0088] The primary protection strategy in each adjustment period is generated in turn;

[0089] The primary protection strategy sequence B, B=(b1, b2…bi…bn), is established, wherein bi is the primary protection strategy in the i th adjustment period.

[0090] Specifically, the running simulation model is constructed to simulate the operation of the circuit breaker, so as to generate the variation curve of each characteristic index, thereby providing data support for setting the primary control strategy in each adjustment period.

[0091] Specifically, the characteristic index includes but is not limited to: device operation time, aging state, current measurement cumulative error and other parameters that will interfere with the gradient selection mechanism.

[0092] Specifically, the single primary protection strategy includes multiple current threshold values and action time corresponding to each current threshold value, and when the time of the current exceeding the current threshold value exceeds the action time, the circuit breaker executes the circuit breaking instruction.

[0093] Specifically, by constructing the gradient selection mechanism, the misoperation of the circuit breaker caused by the transient excitation inrush current is avoided, and the demand of the device is met at the same time, thereby ensuring the safe operation of the transformer.

[0094] Specifically, when the adjustment instruction is generated according to all the expected reference values, it includes:

[0095] The variation evaluation value f is generated according to all the expected reference values;

[0096] f= βi*(c i -c' i ) 2 ;

[0097] Wherein, θ is the number of characteristic indexes, c i is the expected reference value of the i th characteristic index at the starting time node of the target adjustment period; βi is the influence factor of the i th characteristic index, and c' ian initial reference value of the i-th characteristic index;

[0098] a preset first variation evaluation value threshold F1;

[0099] if f < F1, no adjustment instruction is generated, and the initial protection strategy is set as the first-level protection strategy of the target adjustment period;

[0100] if f > F1, a first-level adjustment instruction is generated, the initial protection strategy is revised according to the first-level adjustment instruction, and the first-level protection strategy of the target adjustment period is generated according to the revision result.

[0101] Specifically, the greater the variation evaluation value, the greater the fluctuation of the operating parameters of the circuit breaker, and thus the initial protection strategy needs to be revised in time to ensure the accurate operation of the circuit breaker.

[0102] Specifically, when the initial protection strategy is generated, the historical operating parameters meeting the initial reference values of the characteristic indexes are optimized to construct the corresponding gradient selection mechanism.

[0103] Specifically, when the characteristic indexes fluctuate greatly, the historical operating parameters meeting the real-time reference values of the characteristic indexes are optimized according to the first-level adjustment instruction to generate the corresponding first-level control strategy.

[0104] It can be understood that in the above embodiments, the operating parameters of the circuit breaker are used to set multiple characteristic indexes, and the expected variation curve of each characteristic index is generated by establishing an operating simulation model, so as to predict the state of the circuit breaker in each adjustment period, dynamically adjust the corresponding first-level protection strategy, reduce the misoperation risk of the circuit breaker, and ensure the safe operation of the transformer.

[0105] In the preferred embodiments of the present application, when it is determined whether to generate a maintenance instruction, the following steps are included:

[0106] obtaining the operating parameters of the current feedback time node, and generating a risk evaluation value g of the current feedback time node according to the operating parameters;

[0107] presetting a first risk evaluation value threshold G1 and a second risk evaluation value threshold G2;

[0108] if g < G1, no maintenance instruction is generated for the current feedback time node;

[0109] if G1 ≤ g < G2, a fluctuation evaluation value d of the current feedback time node is generated, and it is determined whether the current feedback time node generates a maintenance instruction according to the fluctuation evaluation value d;

[0110] if g > G2, a first-level maintenance instruction is generated for the current feedback time node.

[0111] Specifically, when generating the risk evaluation value g of the current feedback time node, the following is included:

[0112] g = e3 * Q3 * [ (ri * ci)] + e4 * Q4 * Y;

[0113] wherein e3 is a preset third weight coefficient; e4 is a preset third weight coefficient; Q3 is a preset third fixed coefficient; Q4 is a preset fourth fixed coefficient; u is the number of risk evaluation indexes; ri is the influence factor of the i th risk evaluation index; ci is the reference value of the i th risk evaluation index at the current feedback time node; Y is the set first-level reference value of the operating parameter in the last adjustment period based on the corresponding adjustment period of the current feedback time node.

[0114] Specifically, in the above embodiment, all parameters in the model are normalized by the preset third fixed coefficient and the fourth fixed coefficient, so that each parameter is in the same value range.

[0115] Specifically, the risk evaluation indexes include the operating parameters of the circuit breaker device, the operating parameters of the connected transformer, the current fluctuation parameters passing through the circuit breaker, the cumulative operating time of the circuit breaker, and the like. The greater the risk evaluation value is, the greater the possibility of failure of the current circuit breaker is.

[0116] Specifically, the first-level maintenance instruction means that the current circuit breaker has an abnormal operating state, and needs to be timely maintained to eliminate the risk of failure and ensure the safe operation of the transformer and reduce the risk of misoperation of the circuit breaker.

[0117] In the preferred embodiment of the present application, when generating the fluctuation evaluation value d of the current feedback time node, the following is included:

[0118] generating the actual reference value of each feature index at the current feedback time node;

[0119] generating the fluctuation evaluation value d of the current feedback time node according to all actual reference values;

[0120] presetting a first fluctuation evaluation value threshold D1 and a second fluctuation evaluation value threshold D2;

[0121] if d < D1, the current feedback time node does not generate a first-level maintenance instruction;

[0122] when D1 ≤ d < D2, a first-level correction instruction is generated, and a compensation coefficient m is set according to the first-level correction instruction;

[0123] if m * g > G1, the current feedback time node generates a first-level maintenance instruction; if m * g < G1, the current feedback time node does not generate a maintenance instruction;

[0124] If d>D2, the current feedback time node generates a secondary correction instruction and generates a primary maintenance instruction.

[0125] Specifically, the primary correction instruction refers to the existence of errors between the actual values and the expected values of each characteristic index in the current adjustment period, which leads to the decrease of the accuracy of the current primary protection strategy, thereby possibly causing abnormal operation of the circuit breaker.

[0126] Specifically, the secondary correction instruction refers to the existence of huge errors between the actual values and the expected values of each characteristic index in the current adjustment period, and the operation simulation model has certain defects, which needs to be optimized and corrected, and the corresponding primary protection strategy needs to be re-established. At the same time, a primary maintenance instruction needs to be generated to maintain the circuit breaker and eliminate potential operation risks.

[0127] Specifically, when the fluctuation evaluation value d of the current feedback time node includes:

[0128] d=e5*Q5*[ βi*(c 1i -c' i ) 2 ]+e6*Q6*[ βi*(c 1i -c 2i ) 2 ]

[0129] Wherein, e5 is a preset fifth weight coefficient, e6 is a preset sixth weight coefficient; Q5 is a preset fifth fixed coefficient; Q6 is a preset sixth fixed coefficient; c 1i is the reference value of the i-th characteristic evaluation index at the current feedback time node; θ is the number of characteristic indexes; βi is the influence factor of the i-th characteristic index; c' i is the initial reference value of the i-th characteristic index; c 2i is the expected reference value of the i-th characteristic index at the start time node of the corresponding adjustment period of the current feedback time node.

[0130] Specifically, by presetting the fifth fixed coefficient and the sixth fixed coefficient, all parameters in the model are normalized, so that each parameter is in the same value range.

[0131] Specifically, the greater the fluctuation evaluation value, the greater the difference between the current actual operation state and the expected operation state, and the greater the interference degree of the primary protection strategy in the current adjustment period.

[0132] Specifically, when the compensation coefficient m is set according to the primary correction instruction, it includes:

[0133] The preset first fluctuation evaluation value interval (D3, D4), the second fluctuation evaluation value interval (D4, D5) and the third fluctuation evaluation value interval (D5, D6) are set.

[0134] The fluctuation evaluation value d of the current feedback time node is obtained.

[0135] If the fluctuation evaluation value d is in the preset first fluctuation evaluation value interval, the compensation coefficient m is set as the preset first compensation coefficient m1, that is, m = m1.

[0136] If the fluctuation evaluation value d is in the preset second fluctuation evaluation value interval, the compensation coefficient m is set as the preset second compensation coefficient m2, that is, m = m2.

[0137] If the fluctuation evaluation value d is in the preset third fluctuation evaluation value interval, the compensation coefficient m is set as the preset third compensation coefficient m3, that is, m = m3; and m3 < m2 < m1 < 1.

[0138] Specifically, the first fluctuation evaluation value interval, the second fluctuation evaluation value interval and the third fluctuation evaluation value interval are all between the first fluctuation evaluation value threshold D1 and the second fluctuation evaluation value threshold D2.

[0139] It can be understood that in the above embodiment, the corresponding compensation coefficient is set according to the real-time fluctuation evaluation value, thereby excluding the influence of the decrease in the accuracy of the primary protection strategy on the operation of the circuit breaker, improving the early warning efficiency of the operation risk of the circuit breaker, and reducing the maintenance frequency and maintenance cost.

[0140] According to the first concept of the present application, a plurality of characteristic indexes are set according to the operation parameters of the circuit breaker, and an expected variation curve of each characteristic index is generated by establishing an operation simulation model, so as to predict the state of the circuit breaker in each adjustment period, dynamically adjust the corresponding primary protection strategy, reduce the misoperation risk of the circuit breaker, and ensure the safe operation of the transformer.

[0141] According to the second concept of the present application, the action time under each current threshold is generated by setting the primary protection strategy in each adjustment period, a gradient selection mechanism is constructed, the misoperation of the circuit breaker caused by the transient excitation inrush current is avoided, the needs of the equipment are met, and the safe operation of the transformer is ensured.

[0142] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the technical field, some improvements and replacements can be made without departing from the technical principles of the present application, and these improvements and replacements should also be regarded as the protection scope of the present application.

Claims

1. A method of protection for a low voltage side circuit breaker of a 35 kV tank transformer, characterized in that, The application relates to a circuit breaker protection strategy generation method and device. The method comprises the following steps: generating a historical evaluation value according to device parameters and historical operation parameters, and constructing multiple adjustment periods according to the historical evaluation value; sequentially setting a first-level protection strategy in each adjustment period; obtaining operation parameters of the circuit breaker according to a preset feedback time node, and determining whether to generate a maintenance instruction; when the multiple adjustment periods are constructed, the method comprises the following steps: p = e1*Q1 β 1i *ji]+e2*Q2* β 2i *ki]; Wherein, e1 is a preset first weight coefficient; e2 is a preset second weight coefficient; Q1 is a preset first fixed coefficient; Q2 is a preset second fixed coefficient; is the number of equipment evaluation indexes; β 1i is the influence factor of the i-th equipment evaluation index; j i is the reference value of the i-th equipment evaluation index; 2 is the number of operation evaluation indexes; β 2i is the influence factor of the i-th operation evaluation index; k i is the reference value of the i-th operation evaluation index; generating a historical evaluation value p; setting a length t of a single adjustment period according to the historical evaluation value p; establishing an adjustment period sequence A based on a time sequence and the length t of the single adjustment period, A=(a1, a2…ai…an), wherein ai is the ith adjustment period set based on the time sequence; and n is the number of adjustment periods; when the first-level protection strategy in each adjustment period is sequentially set, the method comprises the following steps: setting multiple characteristic indexes and an operation simulation model according to the historical operation parameters; generating initial reference values of the multiple characteristic indexes; constructing an initial protection strategy according to the initial reference values of the multiple characteristic indexes, wherein the initial protection strategy comprises multiple current fixed values and action time lengths corresponding to the multiple current fixed values; sequentially setting ai as a target adjustment period according to the adjustment period sequence A; generating expected reference values of the multiple characteristic indexes at a starting time node of the target adjustment period according to the operation simulation model; determining whether to generate an adjustment instruction according to all the expected reference values, and generating the first-level protection strategy in the target adjustment period; sequentially generating the first-level protection strategy in each adjustment period; 2. The method of claim 1, wherein the 35 kV box transformer low voltage side circuit breaker protection method is characterized by, establishing a first-level protection strategy sequence B, B=(b1, b2…bi…bn), wherein bi is the first-level protection strategy in the ith adjustment period. when the adjustment instruction is generated according to all the expected reference values, the method comprises the following steps: f= βi*(c i -c' i ) 2 ; wherein θ is the number of characteristic indexes, c i is the expected reference value of the i-th characteristic index at the starting time node of the target adjustment period; βi is the influence factor of the i-th characteristic index, c i is the initial reference value of the i-th characteristic index; generating a variation evaluation value f according to all the expected reference values; presetting a first variation evaluation value threshold F1; if f 3. The method of claim 2, wherein the 35 kV box transformer low voltage side circuit breaker protection method is characterized by, if f>F1, a first-level adjustment instruction is generated, the initial protection strategy is corrected according to the first-level adjustment instruction, and the first-level protection strategy of the target adjustment period is generated according to a correction result. when it is determined whether to generate a maintenance instruction, the method comprises the following steps: obtaining operation parameters at a current feedback time node, and generating a risk evaluation value g of the current feedback time node according to the operation parameters; presetting a first risk evaluation value threshold G1 and a second risk evaluation value threshold G2; if g if G1≤g 4. The method of claim 3, wherein the 35 kV box transformer low voltage side circuit breaker protection method is characterized by, if g>G2, a first-level maintenance instruction is generated at the current feedback time node. g=e3*Q3*[ (ri*ci)]+e4*Q4*Y; when the risk evaluation value g of the current feedback time node is generated, the method comprises the following steps: wherein e3 is a preset third weight coefficient; e4 is a preset third weight coefficient; Q3 is a preset third fixed coefficient; Q4 is a preset fourth fixed coefficient; u is the number of risk evaluation indexes; ri is an influence factor of the ith risk evaluation index; ci is a reference value of the ith risk evaluation index at the current feedback time node; and Y is a first-level reference value set based on operation parameters in a previous adjustment period of a corresponding adjustment period of the current feedback time node.

5. The method of claim 4, wherein the 35 kV box transformer low voltage side circuit breaker protection method is characterized by, The generating fluctuation evaluation value d of the current feedback time node comprises: Generating actual reference values of each characteristic index at the current feedback time node; Generating fluctuation evaluation value d of the current feedback time node according to all actual reference values; Pre-setting first fluctuation evaluation value threshold D1 and second fluctuation evaluation value threshold D2; If d < D1, the current feedback time node does not generate first-level maintenance instruction; If D1 ≤ d < D2, generating first-level correction instruction and setting compensation coefficient m according to the first-level correction instruction; If m * g > G1, the current feedback time node generates first-level maintenance instruction; if m * g < G1, the current feedback time node does not generate maintenance instruction; If d > D2, the current feedback time node generates second-level correction instruction and generates first-level maintenance instruction.

6. The method of claim 5, wherein the 35 kV box transformer low voltage side circuit breaker protection method is characterized by, The generating fluctuation evaluation value d of the current feedback time node comprises: d=e5*Q5*[ βi*(c 1i -c' i ) 2 ]+e6*Q6*[ βi*(c 1i -c 2i ) 2 ] wherein e5 is a preset fifth weight coefficient, e6 is a preset sixth weight coefficient; Q5 is a preset fifth fixed coefficient; Q6 is a preset sixth fixed coefficient; c 1i is a reference value of the i-th feature evaluation value indicator at a current feedback time node; θ is the number of feature indicators; βi is an influence factor of the i-th feature indicator; c i is an initial reference value of the i-th feature indicator; c 2i is an expected reference value of the i-th feature indicator at a starting time node of an adjustment period corresponding to the current feedback time node.

7. The method of claim 6, wherein the 35 kV box transformer low voltage side circuit breaker protection method is characterized by, Setting compensation coefficient m according to first-level correction instruction comprises: Pre-setting first fluctuation evaluation value interval (D3, D4), second fluctuation evaluation value interval (D4, D5) and third fluctuation evaluation value interval (D5, D6); Obtaining fluctuation evaluation value d of the current feedback time node; If fluctuation evaluation value d is in the preset first fluctuation evaluation value interval, setting compensation coefficient m as preset first compensation coefficient m1, i.e. m = m1; If fluctuation evaluation value d is in the preset second fluctuation evaluation value interval, setting compensation coefficient m as preset second compensation coefficient m2, i.e. m = m2; If fluctuation evaluation value d is in the preset third fluctuation evaluation value interval, setting compensation coefficient m as preset third compensation coefficient m3, i.e. m = m3; and m3 < m2 < m1 < 1.

Images