Transformer early warning method and system based on accumulated short circuit impact

Abstract

The invention discloses a transformer early warning method and system based on accumulated short-circuit impact, and the method comprises the steps: calculating the short-circuit current peak value ratio of each voltage side according to the crossing short-circuit current peak value and the short-circuit-tolerant current value of each voltage side in each recording data, thereby determining the accumulated integral calculation rule of each voltage side, and carrying out the early warning of the transformer. And finally, performing comprehensive analysis according to the total accumulated integral value of each voltage side, and determining an early warning scheme of the to-be-detected transformer, namely, improving the accuracy of an early warning analysis result of the transformer through a comprehensive analysis mode, and further improving the reliability of the early warning scheme of the transformer. The problems that in the prior art, a mode of selecting a single maximum value parameter to carry out early warning analysis and calculation is easy to carry out comprehensive and comprehensive analysis on the transformer due to the fact that the parameter is too single, then the accuracy of early warning analysis and calculation of the transformer is low, and finally the reliability of an early warning scheme of the transformer is low are solved.

Description

Technical Field

[0001] The present invention relates to the field of transformer early warning, and particularly to a transformer early warning method and system based on cumulative short-circuit impact. Background Art

[0002] During long-term operation, a transformer will inevitably be repeatedly impacted by fault through-currents for many times, resulting in cumulative mechanical damage to components such as coils. Timely early warning analysis of the transformer under the impact of fault through-currents has become a key task for power grid operation units, which can effectively avoid power grid safety accidents.

[0003] Currently, early warning analysis of the transformer under the impact of fault through-currents is mainly carried out by means of simulation experiments, regular on-site tests on the transformer or calculations using computational models. However, in the prior art, usually, the maximum value parameter is directly selected based on the impact of the fault through-current on the transformer, and early warning analysis calculations are carried out based on this. The method of carrying out early warning analysis calculations by selecting the maximum value parameter in the prior art is prone to comprehensive and overall analysis of the transformer due to the over-simplification of the parameter, resulting in low accuracy of the early warning analysis of the transformer and ultimately low reliability of the early warning scheme for the transformer. Summary of the Invention

[0004] The present invention provides a transformer early warning method and system based on cumulative short-circuit impact, which can solve the problem that the method of carrying out early warning analysis calculations by selecting a single maximum value parameter in the prior art is prone to comprehensive and overall analysis of the transformer due to the over-simplification of the parameter, resulting in low accuracy of the early warning analysis calculations of the transformer and ultimately low reliability of the early warning scheme for the transformer.

[0005] To solve the above technical problems, an embodiment of the present invention provides a transformer early warning method based on cumulative short-circuit impact, including:

[0006] Obtain a plurality of recorded wave data and performance parameters of the transformer to be measured in the current time period; wherein, the recorded wave data includes the peak values of the through-short-circuit currents and the through-short-circuit current durations on the three voltage sides of the transformer to be measured; the performance parameters include the peak value of the withstand short-circuit current and the effective value of the through-short-circuit current of the transformer to be measured; the three voltage sides include the high voltage side, the medium voltage side, and the low voltage side;

[0007] For each voltage side of each recorded wave data, calculate the short-circuit current peak ratio of each voltage side according to the peak value of the through-short-circuit current and the peak value of the withstand short-circuit current of each voltage side;

[0008] Compare the short-circuit current peak ratios of each voltage side with a preset threshold;

[0009] When the peak ratio is greater than or equal to a preset threshold, assign a first preset integral value to the voltage side where the peak ratio is less than the preset interval, assign a second preset integral value to the voltage side where the peak ratio is within the preset interval, and assign a third preset integral value to the voltage side where the peak ratio is greater than the preset interval, to obtain the integral values of each voltage side, and then calculate the first cumulative integral value of each voltage side; wherein, the preset threshold is less than the minimum value of the preset interval; the third preset integral value is greater than the second preset integral value; the second preset integral value is greater than the first preset integral value;

[0010] When the peak ratio is less than the preset threshold, calculate the effective total integral value of the through-fault short-circuit current of each voltage side according to the through-fault short-circuit current duration and the effective value of the through-fault short-circuit current of each voltage side, and then calculate the second cumulative integral value of each voltage side;

[0011] According to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer under test, calculate the total cumulative integral value of each voltage side of the transformer under test, and then determine the early warning scheme of the transformer under test.

[0012] Further, the calculating the effective total integral value of the through-fault short-circuit current of each voltage side according to the through-fault short-circuit current duration and the effective value of the through-fault short-circuit current of each voltage side includes:

[0013] When the peak ratio is less than the preset threshold, calculate the effective integral value of the through-fault short-circuit current of each voltage side of each recording data according to the through-fault short-circuit current duration and the effective value of the through-fault short-circuit current of each voltage side of each recording data;

[0014] According to the effective integral values of the through-fault short-circuit current of each voltage side of each recording data, perform a summation calculation on each voltage side respectively to obtain the effective total integral value of the through-fault short-circuit current of each voltage side.

[0015] Further, the calculation formula for the effective integral value of the through-fault short-circuit current of each voltage side of each recording data is:

[0016]

[0017] wherein, eH n is the effective integral value of the through-fault short-circuit current of the high voltage side of the nth recording data; eM n is the effective integral value of the through-fault short-circuit current of the medium voltage side of the nth recording data; eL n is the effective integral value of the through-fault short-circuit current of the low voltage side of the nth recording data; n is the number of the recording data; I n，H is the effective value of the through-fault short-circuit current of the high voltage side of the nth recording data; I n，M is the effective value of the through-fault short-circuit current of the medium voltage side of the nth recording data; I n，Lis the effective value of the through short-circuit current on the low-voltage side of the nth recorded wave data; Δt n，H is the duration of the through short-circuit current on the high-voltage side of the nth recorded wave data; Δt n，M is the duration of the through short-circuit current on the medium-voltage side of the nth recorded wave data; Δt n，L is the duration of the through short-circuit current on the low-voltage side of the nth recorded wave data.

[0018] Furthermore, the calculation formula for the second cumulative integral value of each voltage side is:

[0019]

[0020] wherein, SH2 is the second cumulative integral value on the high-voltage side; SM2 is the second cumulative integral value on the medium-voltage side; SL2 is the second cumulative integral value on the low-voltage side; eH is the effective total integral value of the through short-circuit current on the high-voltage side; eM is the effective total integral value of the through short-circuit current on the high-voltage side; eL is the effective total integral value of the through short-circuit current on the high-voltage side; a H and b H are the first preset parameter and the second preset parameter for calculating the second cumulative integral value on the high-voltage side respectively; a M and b M are the first preset parameter and the second preset parameter for calculating the second cumulative integral value on the medium-voltage side respectively; a L and b L are the first preset parameter and the second preset parameter for calculating the second cumulative integral value on the low-voltage side respectively.

[0021] Furthermore, calculating the total cumulative integral value of each voltage side of the transformer under test according to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer under test, and then determining the early warning scheme of the transformer under test, includes:

[0022] Calculating the total cumulative integral value of each voltage side of the transformer under test according to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer under test;

[0023] Comparing the total cumulative integral value of each voltage side with each preset early warning interval to determine the early warning interval where the total cumulative integral value of each voltage side is located; wherein, each early warning interval corresponds to an early warning level;

[0024] Determining the early warning level corresponding to each voltage side according to the early warning interval where the total cumulative integral value of each voltage side is located; wherein, each early warning level corresponds to an early warning scheme;

[0025] Taking the highest early warning level as the target early warning level, and then taking the early warning scheme corresponding to the target early warning level as the early warning scheme of the transformer under test.

[0026] Based on the above method embodiment, the present invention correspondingly provides a system embodiment;

[0027] An embodiment of the present invention provides a transformer early warning system based on cumulative short - circuit impact, including: a data acquisition module, a peak ratio calculation module, an integration rule selection module, a first cumulative integral value calculation module, a second cumulative integral value calculation module, and an early warning module;

[0028] The data acquisition module is used to acquire a plurality of recorded wave data and performance parameters of the transformer under test in the current period; wherein, the recorded wave data includes the peak values of the through - short - circuit current and the through - short - circuit current duration on the three voltage sides of the transformer under test; the performance parameters include the peak value of the withstand short - circuit current and the effective value of the through - short - circuit current of the transformer under test; the three voltage sides include the high - voltage side, the medium - voltage side, and the low - voltage side;

[0029] The peak ratio calculation module is used to calculate the short - circuit current peak ratio of each voltage side for each recorded wave data according to the peak value of the through - short - circuit current and the peak value of the withstand short - circuit current of each voltage side;

[0030] The integration rule selection module is used to compare the short - circuit current peak ratio of each voltage side with a preset threshold;

[0031] The first cumulative integral value calculation module is used to, when the peak ratio is greater than or equal to the preset threshold, assign a first preset integral value to the voltage side where the peak ratio is less than the preset interval, assign a second preset integral value to the voltage side where the peak ratio is within the preset interval, and assign a third preset integral value to the voltage side where the peak ratio is greater than the preset interval, to obtain the integral values of each voltage side, and then calculate the first cumulative integral value of each voltage side; wherein, the preset threshold is less than the minimum value of the preset interval; the third preset integral value is greater than the second preset integral value; the second preset integral value is greater than the first preset integral value;

[0032] The second cumulative integral value calculation module is used to, when the peak ratio is less than the preset threshold, calculate the effective total integral value of the through - short - circuit current of each voltage side according to the through - short - circuit current duration and the effective value of the through - short - circuit current of each voltage side, and then calculate the second cumulative integral value of each voltage side;

[0033] The early warning module is used to calculate the total cumulative integral value of each voltage side of the transformer under test according to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer under test, and then determine the early warning plan for the transformer under test.

[0034] Further, calculating the effective total integral value of the through - short - circuit current of each voltage side according to the through - short - circuit current duration and the effective value of the through - short - circuit current of each voltage side includes:

[0035] When the peak ratio is less than a preset threshold, according to the duration of the through-fault short-circuit current and the effective value of the through-fault short-circuit current on each voltage side of each recorded wave data, calculate the effective integral value of the through-fault short-circuit current on each voltage side of each recorded wave data;

[0036] According to the effective integral values of the through-fault short-circuit current on each voltage side of each recorded wave data, perform a summation calculation on each voltage side respectively to obtain the effective total integral value of the through-fault short-circuit current on each voltage side.

[0037] Further, the calculation formula for the effective integral value of the through-fault short-circuit current on each voltage side of each recorded wave data is:

[0038]

[0039] where eH n is the effective integral value of the through-fault short-circuit current on the high-voltage side of the nth recorded wave data; eM n is the effective integral value of the through-fault short-circuit current on the medium-voltage side of the nth recorded wave data; eL n is the effective integral value of the through-fault short-circuit current on the low-voltage side of the nth recorded wave data; n is the number of the recorded wave data; I n，H is the effective value of the through-fault short-circuit current on the high-voltage side of the nth recorded wave data; I n，M is the effective value of the through-fault short-circuit current on the medium-voltage side of the nth recorded wave data; I n，L is the effective value of the through-fault short-circuit current on the low-voltage side of the nth recorded wave data; Δt n，H is the duration of the through-fault short-circuit current on the high-voltage side of the nth recorded wave data; Δt n，M is the duration of the through-fault short-circuit current on the medium-voltage side of the nth recorded wave data; Δt n，L is the duration of the through-fault short-circuit current on the low-voltage side of the nth recorded wave data.

[0040] Further, the calculation formula for the second cumulative integral value on each voltage side is:

[0041]

[0042] where SH2 is the second cumulative integral value on the high-voltage side; SM2 is the second cumulative integral value on the medium-voltage side; SL2 is the second cumulative integral value on the low-voltage side; eH is the effective total integral value of the through-fault short-circuit current on the high-voltage side; eM is the effective total integral value of the through-fault short-circuit current on the high-voltage side; eL is the effective total integral value of the through-fault short-circuit current on the high-voltage side; a H and b H are the first preset parameter and the second preset parameter for calculating the second cumulative integral value on the high-voltage side respectively; a M and bM are respectively the first preset parameter and the second preset parameter for the second cumulative integral value on the voltage side in the calculation; a L and b L are respectively the first preset parameter and the second preset parameter for the second cumulative integral value on the low-voltage side in the calculation.

[0043] Furthermore, the warning module includes: a total cumulative integral value calculation unit, a warning judgment unit, and a warning scheme generation unit;

[0044] The total cumulative integral value calculation unit calculates the total cumulative integral value of each voltage side of the transformer under test according to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer under test;

[0045] The warning judgment unit is used to compare the total cumulative integral value of each voltage side with each preset warning interval, determine the warning interval where the total cumulative integral value of each voltage side is located, and determine the warning level corresponding to each voltage side according to the warning interval where the total cumulative integral value of each voltage side is located; wherein, each warning interval corresponds to a warning level; each warning level corresponds to a warning scheme;

[0046] The warning scheme generation unit is used to take the highest warning level as the target warning level, and then take the warning scheme corresponding to the target warning level as the warning scheme of the transformer under test.

[0047] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0048] The present invention calculates the short-circuit current peak ratio of each voltage side in each recording data according to the peak value of the through short-circuit current and the withstand short-circuit current value of each voltage side in each recording data, compares the short-circuit current peak ratio of each voltage side in each recording data with a preset threshold, determines the cumulative integral calculation rule of each voltage side according to the comparison result, and performs integral calculation on each voltage side, and then statistically calculates the total cumulative integral value of each voltage side of the transformer under test. Finally, the warning scheme of the transformer under test is determined according to the total cumulative integral value of each voltage side; that is, the present invention assigns integral values to the three voltage sides in the recording data of the transformer under test through a preset cumulative integral calculation rule, calculates the total cumulative integral value of the three voltage sides of the transformer under test, and performs comprehensive warning analysis on the transformer through the comprehensive analysis method, improving the accuracy of the warning analysis result of the transformer, and further improving the reliability of the warning scheme of the transformer, solving the problem that the prior art is prone to inaccurate warning analysis calculation of the transformer due to too single parameters when selecting a single maximum value parameter for warning analysis calculation, resulting in low accuracy of the warning analysis calculation of the transformer and ultimately low reliability of the warning scheme of the transformer. Description of the Drawings

[0049] Figure 1 : It is a flowchart of steps of a transformer early warning method based on cumulative short - circuit impact provided by an embodiment of the present invention;

[0050] Figure 2 : It is a system structure diagram of a transformer early warning system based on cumulative short - circuit impact provided by an embodiment of the present invention. Specific embodiments

[0051] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0052] In the description of the present invention, it should be understood that the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features.

[0053] Embodiment 1:

[0054] Refer to Figure 1 , which is a flowchart of steps of a transformer early warning method based on cumulative short - circuit impact provided by an embodiment of the present invention. The method at least includes the following steps:

[0055] Step S1: Obtain several recorded wave data and performance parameters of the transformer to be measured in the current period; wherein, the recorded wave data includes the peak value of the through - short - circuit current and the duration of the through - short - circuit current on the three voltage sides of the transformer to be measured; the performance parameters include the peak value of the withstand short - circuit current and the effective value of the through - short - circuit current of the transformer to be measured; the three voltage sides include the high - voltage side, the medium - voltage side, and the low - voltage side;

[0056] In this embodiment, the recorded wave data of the transformer to be measured within the current preset period can be collected by using a fault recorder, and the performance parameters of the transformer to be measured can be obtained by checking the nameplate of the transformer to be measured or consulting the manufacturer.

[0057] Step S2: For each voltage side of each recorded wave data, calculate the short - circuit current peak ratio of each voltage side according to the peak value of the through - short - circuit current and the peak value of the withstand short - circuit current of each voltage side;

[0058] In this embodiment, calculate the ratio of the peak value of the through - short - circuit current of each voltage side of each recorded wave data to the peak value of the withstand short - circuit current of the corresponding voltage side to obtain the short - circuit current peak ratio of each voltage side of each recorded wave data.

[0059] Step S3: Compare the peak ratio of the short-circuit current on each voltage side with a preset threshold value;

[0060] In this embodiment, the preset threshold value can be set to 0.2, and the specific actual value can be adjusted by technicians according to the actual situation.

[0061] Step S4: When the peak ratio is greater than or equal to the preset threshold value, assign a first preset integral value to the voltage side whose peak ratio is less than the preset interval, assign a second preset integral value to the voltage side whose peak ratio is within the preset interval, and assign a third preset integral value to the voltage side whose peak ratio is greater than the preset interval, to obtain the integral values of each voltage side, and then calculate the first cumulative integral value of each voltage side; wherein, the preset threshold value is less than the minimum value of the preset interval; the third preset integral value is greater than the second preset integral value; the second preset integral value is greater than the first preset integral value;

[0062] Exemplarily, taking the high-voltage side as an example, when the peak ratio is greater than or equal to the preset threshold value, assign a first preset integral value to the high-voltage side whose peak ratio is less than the preset interval, assign a second preset integral value to the high-voltage side whose peak ratio is within the preset interval, and assign a third preset integral value to the voltage side whose peak ratio is greater than the preset interval, to obtain the integral values of each high-voltage side when the peak ratio is greater than or equal to the preset threshold value, and sum up the integral values of each high-voltage side to calculate the first cumulative integral value of the high-voltage side; wherein, the preset threshold value can be set to 0.2, and the specific actual value can be adjusted by technicians according to the actual situation; the preset interval can be set to [0.5, 0.7], and the specific actual value can be adjusted by technicians according to the actual situation; the first preset integral value can be set to 2, and the specific actual value can be adjusted by technicians according to the actual situation; the first preset integral value can be set to 4, and the specific actual value can be adjusted by technicians according to the actual situation; the first preset integral value can be set to 10, and the specific actual value can be adjusted by technicians according to the actual situation.

[0063] Exemplarily, the specific embodiments of the medium-voltage side and the low-voltage side are the same as the above example of the high-voltage side.

[0064] Step S5: When the peak ratio is less than the preset threshold value, calculate the effective total integral value of the short-circuit current passing through each voltage side according to the duration of the short-circuit current passing through each voltage side and the effective value of the short-circuit current passing through each voltage side, and then calculate the second cumulative integral value of each voltage side;

[0065] In this embodiment, calculating the effective total integral value of the short-circuit current passing through each voltage side according to the duration of the short-circuit current passing through each voltage side and the effective value of the short-circuit current passing through each voltage side includes:

[0066] When the peak ratio is less than the preset threshold, according to the duration of the through-fault short-circuit current and the effective value of the through-fault short-circuit current on each voltage side of each recorded wave data, calculate the effective integral value of the through-fault short-circuit current on each voltage side of each recorded wave data;

[0067] In this embodiment, the calculation formula for the effective integral value of the through-fault short-circuit current on each voltage side of each recorded wave data is:

[0068]

[0069] where, eH n is the effective integral value of the through-fault short-circuit current on the high-voltage side of the nth recorded wave data; eM n is the effective integral value of the through-fault short-circuit current on the medium-voltage side of the nth recorded wave data; eL n is the effective integral value of the through-fault short-circuit current on the low-voltage side of the nth recorded wave data; n is the number of the recorded wave data; I n，H is the effective value of the through-fault short-circuit current on the high-voltage side of the nth recorded wave data; I n，M is the effective value of the through-fault short-circuit current on the medium-voltage side of the nth recorded wave data; I n，L is the effective value of the through-fault short-circuit current on the low-voltage side of the nth recorded wave data; Δt n，H is the duration of the through-fault short-circuit current on the high-voltage side of the nth recorded wave data; Δt n，M is the duration of the through-fault short-circuit current on the medium-voltage side of the nth recorded wave data; Δt n，L is the duration of the through-fault short-circuit current on the low-voltage side of the nth recorded wave data;

[0070] According to the effective integral value of the through-fault short-circuit current on each voltage side of each recorded wave data, perform a summation calculation on each voltage side respectively to obtain the effective total integral value of the through-fault short-circuit current on each voltage side.

[0071] In this embodiment, the calculation formula for the second cumulative integral value on each voltage side is:

[0072]

[0073] where, SH2 is the second cumulative integral value on the high-voltage side; SM2 is the second cumulative integral value on the medium-voltage side; SL2 is the second cumulative integral value on the low-voltage side; eH is the effective total integral value of the through-fault short-circuit current on the high-voltage side; eM is the effective total integral value of the through-fault short-circuit current on the high-voltage side; eL is the effective total integral value of the through-fault short-circuit current on the high-voltage side; a H and b H are the first preset parameter and the second preset parameter for calculating the second cumulative integral value on the high-voltage side respectively; a M and bM are respectively the first preset parameter and the second preset parameter of the second cumulative integral value on the voltage side in the calculation; a L and b L are respectively the first preset parameter and the second preset parameter of the second cumulative integral value on the low-voltage side in the calculation; a H, a M and a L can be set to 10, and the specific actual value can be set by technicians according to the actual situation; b H, b M and b L can be set to 1250, and the specific actual value can be set by technicians according to the actual situation;

[0074] Step S6: Calculate the total cumulative integral values of each voltage side of the transformer under test according to the first cumulative integral values and the second cumulative integral values of each voltage side of the transformer under test, and then determine the early warning scheme of the transformer under test.

[0075] In this embodiment, the calculating the total cumulative integral values of each voltage side of the transformer under test according to the first cumulative integral values and the second cumulative integral values of each voltage side of the transformer under test, and then determining the early warning scheme of the transformer under test includes:

[0076] Calculate the total cumulative integral values of each voltage side of the transformer under test according to the first cumulative integral values and the second cumulative integral values of each voltage side of the transformer under test;

[0077] Compare the total cumulative integral values of each voltage side with each preset early warning interval to determine the early warning interval where the total cumulative integral value of each voltage side is located; wherein, each early warning interval corresponds to an early warning level;

[0078] Determine the early warning level corresponding to each voltage side according to the early warning interval where the total cumulative integral value of each voltage side is located; wherein, each early warning level corresponds to an early warning scheme;

[0079] Take the highest early warning level as the target early warning level, and then take the early warning scheme corresponding to the target early warning level as the early warning scheme of the transformer under test.

[0080] Exemplarily, three warning intervals are set, namely [0, 5], [6, 9] and [10, +∞). When the total cumulative integral value on the high-voltage side is within [0, 5], the warning level for the high-voltage side of the transformer is determined as a third-level warning, and the corresponding warning plan for the third-level warning is to make a short-circuit impact record; when the total cumulative integral value on the medium-voltage side is within [6, 9], the warning level for the medium-voltage side of the transformer is determined as a second-level warning, and the corresponding warning plan for the second-level warning is to monitor the oil chromatogram and test data of the transformer; when the total cumulative integral value on the low-voltage side is within [10, +∞), the warning level for the low-voltage side of the transformer is determined as a first-level warning, and the corresponding warning plan for the first-level warning is to conduct a shutdown inspection of the transformer; according to the warning levels and warning plans of the high-voltage side, medium-voltage side and low-voltage side of the transformer, the warning plan for the transformer is determined; wherein, the severity of the first-level warning is greater than that of the second-level warning, and the severity of the second-level warning is greater than that of the third-level warning.

[0081] Embodiment 2:

[0082] Referring to Figure 2 , which is a system structure diagram of a transformer warning system based on cumulative short-circuit impact provided by an embodiment of the present invention. The system at least includes: a data acquisition module, a peak ratio calculation module, an integration rule selection module, a first cumulative integral value calculation module, a second cumulative integral value calculation module and a warning module;

[0083] The data acquisition module is used to acquire a plurality of recorded wave data and performance parameters of the transformer to be measured in the current period; wherein, the recorded wave data includes the peak value of the through short-circuit current and the duration of the through short-circuit current of the three voltage sides of the transformer to be measured; the performance parameters include the peak value of the withstand short-circuit current and the effective value of the through short-circuit current of the transformer to be measured; the three voltage sides include the high-voltage side, the medium-voltage side and the low-voltage side;

[0084] The peak ratio calculation module is used to calculate the short-circuit current peak ratio of each voltage side according to the peak value of the through short-circuit current and the peak value of the withstand short-circuit current of each voltage side for each voltage side of each recorded wave data.

[0085] The integration rule selection module is used to compare the short-circuit current peak ratio of each voltage side with a preset threshold;

[0086] The first cumulative integral value calculation module is used to, when the peak ratio is greater than or equal to a preset threshold, assign a first preset integral value to the voltage side where the peak ratio is less than the preset interval, assign a second preset integral value to the voltage side where the peak ratio is within the preset interval, and assign a third preset integral value to the voltage side where the peak ratio is greater than the preset interval, so as to obtain the integral values of each voltage side, and then calculate the first cumulative integral value of each voltage side; wherein, the preset threshold is less than the minimum value of the preset interval; the third preset integral value is greater than the second preset integral value; the second preset integral value is greater than the first preset integral value;

[0087] The second cumulative integral value calculation module is used to, when the peak ratio is less than the preset threshold, calculate the effective total integral value of the through-fault short-circuit current of each voltage side according to the through-fault short-circuit current duration and the effective value of the through-fault short-circuit current of each voltage side, and then calculate the second cumulative integral value of each voltage side;

[0088] The early warning module is used to calculate the total cumulative integral value of each voltage side of the transformer under test according to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer under test, and then determine the early warning plan for the transformer under test.

[0089] In this embodiment, calculating the effective total integral value of the through-fault short-circuit current of each voltage side according to the through-fault short-circuit current duration and the effective value of the through-fault short-circuit current of each voltage side includes:

[0090] When the peak ratio is less than the preset threshold, calculate the effective integral value of the through-fault short-circuit current of each voltage side of each recording data according to the through-fault short-circuit current duration and the effective value of the through-fault short-circuit current of each voltage side of each recording data;

[0091] Sum up the effective integral values of the through-fault short-circuit current of each voltage side of each recording data respectively to obtain the effective total integral value of the through-fault short-circuit current of each voltage side.

[0092] In this embodiment, the calculation formula for the effective integral value of the through-fault short-circuit current of each voltage side of each recording data is:

[0093]

[0094] wherein, eH n is the effective integral value of the through-fault short-circuit current of the high voltage side of the nth recording data; eM n is the effective integral value of the through-fault short-circuit current of the medium voltage side of the nth recording data; eL n is the effective integral value of the through-fault short-circuit current of the low voltage side of the nth recording data; n is the number of the recording data; I n，H is the effective value of the through-fault short-circuit current of the high voltage side of the nth recording data; In，M is the effective value of the through short-circuit current on the medium voltage side of the nth recorded wave data; I n，L is the effective value of the through short-circuit current on the low voltage side of the nth recorded wave data; Δt n，H is the duration of the through short-circuit current on the high voltage side of the nth recorded wave data; Δt n，M is the duration of the through short-circuit current on the medium voltage side of the nth recorded wave data; Δt n，L is the duration of the through short-circuit current on the low voltage side of the nth recorded wave data.

[0095] In this embodiment, the calculation formula for the second cumulative integral value of each voltage side is:

[0096]

[0097] Among them, SH2 is the second cumulative integral value on the high voltage side; SM2 is the second cumulative integral value on the medium voltage side; SL2 is the second cumulative integral value on the low voltage side; eH is the effective total integral value of the through short-circuit current on the high voltage side; eM is the effective total integral value of the through short-circuit current on the high voltage side; eL is the effective total integral value of the through short-circuit current on the high voltage side; a H and b H are the first preset parameter and the second preset parameter for calculating the second cumulative integral value on the high voltage side respectively; a M and b M are the first preset parameter and the second preset parameter for calculating the second cumulative integral value on the medium voltage side respectively; a L and b L are the first preset parameter and the second preset parameter for calculating the second cumulative integral value on the low voltage side respectively.

[0098] In this embodiment, the warning module includes: a total cumulative integral value calculation unit, a warning judgment unit, and a warning scheme generation unit;

[0099] The total cumulative integral value calculation unit calculates the total cumulative integral value of each voltage side of the transformer under test according to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer under test;

[0100] The warning judgment unit is used to compare the total cumulative integral value of each voltage side with each preset warning interval, determine the warning interval where the total cumulative integral value of each voltage side is located, and determine the warning level corresponding to each voltage side according to the warning interval where the total cumulative integral value of each voltage side is located; among them, each warning interval corresponds to a warning level; each warning level corresponds to a warning scheme;

[0101] The early warning scheme generation unit is used to take the highest early warning level as the target early warning level, and then take the early warning scheme corresponding to the target early warning level as the early warning scheme of the transformer to be tested.

[0102] The specific embodiments described above further elaborate on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. In particular, for those skilled in the art, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A transformer early warning method based on cumulative short-circuit impact, characterized in that: include: Acquire several waveform data and performance parameters of the transformer to be tested in the current period; wherein the waveform data include the peak value of the through-short-circuit current and the through-short-circuit current duration of the three voltage sides of the transformer to be tested; the performance parameters include the peak value of the short-circuit current withstand and the effective value of the through-short-circuit current of the transformer to be tested; the three voltage sides include the high voltage side, the medium voltage side and the low voltage side; For each voltage side of each waveform data, the short-circuit current peak ratio of each voltage side is calculated according to the short-circuit current peak through and short-circuit current peak withstanding of each voltage side; Comparing the short-circuit current peak ratio of each voltage side with a preset threshold; When the peak ratio is greater than or equal to a preset threshold, a first preset integral value is assigned to the voltage side whose peak ratio is less than a preset interval, a second preset integral value is assigned to the voltage side whose peak ratio is within the preset interval, and a third preset integral value is assigned to the voltage side whose peak ratio is greater than the preset interval, to obtain the integral value of each voltage side, and then calculate the first cumulative integral value of each voltage side; wherein the preset threshold is less than the minimum value of the preset interval; the third preset integral value is greater than the second preset integral value; and the second preset integral value is greater than the first preset integral value; When the peak ratio is less than a preset threshold, the effective total integral value of the through-short-circuit current on each voltage side is calculated according to the through-short-circuit current duration and the through-short-circuit current effective value on each voltage side, and then the second cumulative integral value on each voltage side is calculated; According to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer to be tested, the total cumulative integral value of each voltage side of the transformer to be tested is calculated, and then the early warning scheme of the transformer to be tested is determined.

2. The transformer early warning method based on cumulative short-circuit impact according to claim 1 is characterized in that: The calculating the effective total integral value of the through-the-short-circuit current on each voltage side according to the through-the-short-circuit current duration and the through-the-short-circuit current effective value on each voltage side comprises: When the peak ratio is less than the preset threshold, the effective integral value of the through-short-circuit current on each voltage side of each recording data is calculated according to the through-short-circuit current duration and the through-short-circuit current effective value on each voltage side of each recording data; According to the effective integral value of the through short-circuit current on each voltage side of each recorded data, each voltage side is summed up and calculated respectively to obtain the effective total integral value of the through short-circuit current on each voltage side.

3. The transformer early warning method based on cumulative short-circuit impact according to claim 2 is characterized in that: The calculation formula for the effective integral value of the through-short-circuit current on each voltage side of each recording data is: Among them, eH n eM is the effective integral value of the short-circuit current on the high voltage side of the nth recording data; n is the effective integral value of the short-circuit current on the medium voltage side of the nth recording data; eL n is the effective integral value of the short-circuit current on the low-voltage side of the nth recording data; n is the number of the recording data; I n，H is the effective value of the short-circuit current on the high voltage side of the nth recording data; I n，M is the effective value of the short-circuit current on the medium voltage side of the nth recording data; I n，L is the effective value of the short-circuit current on the low-voltage side of the nth recording data; Δt n，H is the duration of the short-circuit current through the high voltage side of the nth recording data; Δt n，M is the duration of the short-circuit current through the medium voltage side of the nth recording data; Δt n，L It is the duration of the short-circuit current on the low-voltage side of the nth recording data.

4. The transformer early warning method based on cumulative short-circuit impact according to claim 3 is characterized in that: The calculation formula of the second cumulative integral value of each voltage side is: Among them, SH2 is the second cumulative integral value of the high voltage side; SM2 is the second cumulative integral value of the medium voltage side; SL2 is the second cumulative integral value of the low voltage side; eH is the effective total integral value of the through short-circuit current on the high voltage side; eM is the effective total integral value of the through short-circuit current on the high voltage side; eL is the effective total integral value of the through short-circuit current on the high voltage side; a H and b H a is a first preset parameter and a second preset parameter for calculating the second cumulative integral value of the high voltage side respectively; M and b M are respectively a first preset parameter and a second preset parameter of the second cumulative integral value of the voltage side in the calculation; a L and b L The first preset parameter and the second preset parameter are respectively used to calculate the second cumulative integral value of the low voltage side.

5. The transformer early warning method based on cumulative short-circuit impact according to claim 4 is characterized in that: The method of calculating the total cumulative integral value of each voltage side of the transformer to be tested according to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer to be tested, and then determining the early warning scheme of the transformer to be tested, comprises: Calculating the total cumulative integral value of each voltage side of the transformer to be tested according to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer to be tested; Compare the total accumulated integral value of each voltage side with each preset warning interval to determine the warning interval in which the total accumulated integral value of each voltage side is located; wherein each warning interval corresponds to a warning level; Determine the warning level corresponding to each voltage side according to the warning interval in which the total accumulated integral value of each voltage side is located; wherein each warning level corresponds to a warning plan; The highest warning level is taken as the target warning level, and then the warning plan corresponding to the target warning level is taken as the warning plan for the transformer to be tested.

6. A transformer early warning system based on cumulative short-circuit impact, characterized in that: include: A data acquisition module, a peak value ratio calculation module, an integration rule selection module, a first cumulative integral value calculation module, a second cumulative integral value calculation module and an early warning module; The data acquisition module is used to obtain a number of recorded wave data and performance parameters of the transformer to be tested in the current period; wherein the recorded wave data include the peak value of the through short-circuit current and the through short-circuit current duration of the three voltage sides of the transformer to be tested; the performance parameters include the peak value of the short-circuit current withstand and the effective value of the through short-circuit current of the transformer to be tested; the three voltage sides include the high voltage side, the medium voltage side and the low voltage side; The peak ratio calculation module is used to calculate the short-circuit current peak ratio of each voltage side for each voltage side of each recorded wave data according to the short-circuit current peak value and the short-circuit current peak value of each voltage side; The integration rule selection module is used to compare the short-circuit current peak ratio of each voltage side with a preset threshold; The first cumulative integral value calculation module is used to assign a first preset integral value to a voltage side whose peak ratio is less than a preset interval, assign a second preset integral value to a voltage side whose peak ratio is within a preset interval, and assign a third preset integral value to a voltage side whose peak ratio is greater than a preset interval, when the peak ratio is greater than or equal to a preset threshold, to obtain the integral value of each voltage side, and then calculate the first cumulative integral value of each voltage side; wherein the preset threshold is less than the minimum value of the preset interval; the third preset integral value is greater than the second preset integral value; and the second preset integral value is greater than the first preset integral value; The second cumulative integral value calculation module is used to calculate the effective total integral value of the through-short-circuit current on each voltage side according to the through-short-circuit current duration and the through-short-circuit current effective value on each voltage side when the peak ratio is less than a preset threshold, and then calculate the second cumulative integral value on each voltage side; The early warning module is used to calculate the total accumulated integral value of each voltage side of the transformer to be tested according to the first accumulated integral value and the second accumulated integral value of each voltage side of the transformer to be tested, and then determine the early warning scheme of the transformer to be tested.

7. The transformer early warning system based on cumulative short-circuit impact according to claim 6 is characterized in that: The calculating the effective total integral value of the through-the-short-circuit current on each voltage side according to the through-the-short-circuit current duration and the through-the-short-circuit current effective value on each voltage side comprises: When the peak ratio is less than the preset threshold, the effective integral value of the through-short-circuit current on each voltage side of each recording data is calculated according to the through-short-circuit current duration and the through-short-circuit current effective value on each voltage side of each recording data; According to the effective integral value of the through short-circuit current on each voltage side of each recorded data, each voltage side is summed up and calculated respectively to obtain the effective total integral value of the through short-circuit current on each voltage side.

8. The transformer early warning system based on cumulative short-circuit impact according to claim 7 is characterized in that: The calculation formula for the effective integral value of the through-short-circuit current on each voltage side of each recording data is: Among them, eH n eM is the effective integral value of the short-circuit current on the high voltage side of the nth recording data; n is the effective integral value of the short-circuit current on the medium voltage side of the nth recording data; eL n is the effective integral value of the short-circuit current on the low-voltage side of the nth recording data; n is the number of the recording data; I n，H is the effective value of the short-circuit current on the high voltage side of the nth recording data; I n，M is the effective value of the short-circuit current on the medium voltage side of the nth recording data; I n，L is the effective value of the short-circuit current on the low-voltage side of the nth recording data; Δt n，H is the duration of the short-circuit current through the high voltage side of the nth recording data; Δt n，M is the duration of the short-circuit current through the medium voltage side of the nth recording data; Δt n，L It is the duration of the short-circuit current on the low-voltage side of the nth recording data.

9. The transformer early warning system based on cumulative short-circuit impact according to claim 8 is characterized in that: The calculation formula of the second cumulative integral value of each voltage side is: Among them, SH2 is the second cumulative integral value of the high voltage side; SM2 is the second cumulative integral value of the medium voltage side; SL2 is the second cumulative integral value of the low voltage side; eH is the effective total integral value of the through short-circuit current on the high voltage side; eM is the effective total integral value of the through short-circuit current on the high voltage side; eL is the effective total integral value of the through short-circuit current on the high voltage side; a H and b H a is a first preset parameter and a second preset parameter for calculating the second cumulative integral value of the high voltage side respectively; M and b M are respectively a first preset parameter and a second preset parameter of the second cumulative integral value of the voltage side in the calculation; a L and b L The first preset parameter and the second preset parameter are respectively used to calculate the second cumulative integral value of the low voltage side.

10. The transformer early warning system based on cumulative short-circuit impact according to claim 9 is characterized in that: The early warning module includes: a total cumulative integral value calculation unit, an early warning judgment unit and an early warning plan generation unit; The total cumulative integral value calculation unit calculates the total cumulative integral value of each voltage side of the transformer to be tested according to the first cumulative integral value and the second cumulative integral value of each voltage side of the transformer to be tested; The warning judgment unit is used to compare the total cumulative integral value of each voltage side with each preset warning interval, determine the warning interval where the total cumulative integral value of each voltage side is located, and determine the warning level corresponding to each voltage side according to the warning interval where the total cumulative integral value of each voltage side is located; wherein each warning interval corresponds to a warning level; and each warning level corresponds to a warning plan; The warning scheme generating unit is used to take the highest warning level as the target warning level, and then take the warning scheme corresponding to the target warning level as the warning scheme for the transformer to be tested.

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