Current transformer signal compensation method and device

Abstract

The invention discloses a current transformer signal compensation method and device, and belongs to the technical field of electric power measurement, and the method comprises the steps: carrying out the accelerated aging test of an unaged current transformer based on a benchmark reference parameter, and solving an environment calibration parameter and an aging calibration parameter; acquiring a real-time current output value, a real-time temperature, a real-time humidity and a data acquisition time point of the target current transformer; calculating an environment temperature and humidity compensation parameter based on the real-time temperature, the real-time humidity, the environment calibration parameter and the benchmark reference parameter; based on the aging calibration parameters and the data acquisition time points, mutual inductor aging compensation parameters are calculated; performing weighted integration on the environment temperature and humidity compensation parameter and the transformer aging compensation parameter to obtain a transformer signal compensation parameter; and compensating the real-time current output value based on the mutual inductor signal compensation parameter to obtain a current compensation value of the target current mutual inductor. By implementing the current transformer, the problem of low signal compensation accuracy of the current transformer in the prior art can be solved.

Description

Technical Field

[0001] This invention relates to the field of power measurement technology, and in particular to a method and apparatus for signal compensation of current transformers. Background Technology

[0002] Current transformers (CTs) are critical measuring devices in power systems, and the accuracy of their output signals directly affects the reliability of core functions such as relay protection and energy metering. However, in actual operation, CT signals are susceptible to interference from multiple factors. Changes in temperature and humidity can cause drift in parameters such as the permeability of the CT core and the winding resistance. For example, at high temperatures (>60℃), the hysteresis loss of silicon steel sheets increases, leading to a larger ratio difference; high humidity environments (>85%RH) cause changes in the dielectric constant of the insulation material, resulting in phase errors in the output signal. Moreover, with the accumulation of operating time, problems such as the deterioration of the internal insulation material and core fatigue gradually emerge, leading to a decrease in the accuracy of the output signal after long-term operation.

[0003] Existing current transformer signal compensation methods mostly employ fixed temperature coefficients and static parameter corrections, but they fail to consider the coupling effect between temperature and humidity, as well as the impact of current transformer operating time on the output signal. Furthermore, static thresholds are difficult to adapt to the actual operating conditions of current transformers. Therefore, current current transformer signal compensation methods have significant limitations. Summary of the Invention

[0004] This invention provides a method and apparatus for signal compensation of current transformers, which can solve the problem of low accuracy of signal compensation of current transformers in the prior art.

[0005] To address the aforementioned technical problems, this invention provides a current transformer signal compensation method, comprising:

[0006] Obtain reference parameters; wherein, the reference reference parameters include reference temperature, reference humidity and reference current value; the reference current value is the current value output by the unaged current transformer at the reference temperature and the reference humidity;

[0007] Based on the aforementioned benchmark parameters, an accelerated aging test was conducted on the unaged current transformer to solve for the environmental calibration parameters and the aging calibration parameters.

[0008] Real-time acquisition of the target current transformer's real-time current output value, real-time temperature, real-time humidity, and data acquisition time point;

[0009] Based on the real-time temperature, the real-time humidity, the environmental calibration parameters, and the reference parameters, calculate the environmental temperature and humidity compensation parameters;

[0010] Based on the time calibration parameters and the data acquisition time points, calculate the aging compensation parameters of the current transformer;

[0011] The environmental temperature and humidity compensation parameters and the current transformer aging compensation parameters are weighted and integrated to obtain the current transformer signal compensation parameters.

[0012] The real-time current output value is compensated based on the current transformer signal compensation parameters to obtain the current compensation value of the target current transformer.

[0013] As a preferred embodiment, the calculation of environmental temperature and humidity compensation parameters based on the real-time temperature, the real-time humidity, the environmental calibration parameters, and the reference parameters includes:

[0014] The temperature calibration parameters, humidity calibration parameters, and temperature-humidity cross-calibration parameters are determined from the aging calibration parameters.

[0015] The reference temperature and reference humidity are determined from the aforementioned reference parameters;

[0016] Based on the real-time temperature, the real-time humidity, the temperature calibration parameter, the humidity calibration parameter, the temperature and humidity cross-calibration parameter, the reference temperature, and the reference humidity, the environmental temperature and humidity compensation parameters are calculated using the following formula:

[0017] K1=1+α T (TT ref )+α H (HH ref )+α TH (TT ref (HH) ref )

[0018] In the formula, K1 is the environmental temperature and humidity compensation parameter; α T For temperature calibration parameters; α H For humidity calibration parameters; α TH These are the cross-calibration parameters for temperature and humidity; T is the real-time temperature; H is the real-time humidity; T ref For reference temperature; H ref This is for reference humidity.

[0019] As a preferred embodiment, the calculation of the transformer aging compensation parameters based on the aging calibration parameters and the data acquisition time point includes:

[0020] The initial aging offset and aging calibration parameters are determined in the aging calibration parameters;

[0021] Based on the time conversion factor, the data acquisition time points are converted into time parameter values;

[0022] Based on the initial aging offset, the aging calibration parameters, and the time parameter value, the current transformer aging compensation parameters are calculated using the following formula:

[0023] K2=β0+β1·ln(1+t / τ)

[0024] In the formula, K2 is the current transformer aging compensation parameter; β0 is the initial aging offset; β1 is the aging calibration parameter; t is the time parameter value; and τ is the preset current transformer life value.

[0025] The time parameter value is calculated using the following formula:

[0026] t = AF·t h

[0027] In the formula, t is the time parameter value; AF is the time conversion factor; t h This refers to the time point when the data was collected.

[0028] As a preferred embodiment, the step of converting the data acquisition time point into a time parameter value based on a time conversion factor includes:

[0029] Obtain the activation energy of the transformer core of the target current transformer;

[0030] Determine the temperature calibration parameters and humidity calibration parameters from the aging calibration parameters;

[0031] Based on the real-time temperature, the real-time humidity, the activation energy of the transformer core, the temperature calibration parameters, and the humidity calibration parameters, the time conversion factor is calculated using the following formula:

[0032]

[0033] In the formula, AF is the time conversion factor; T is the real-time temperature; H is the real-time humidity; T ref For temperature calibration parameters; H ref For humidity calibration parameters; E a The current transformer core activation energy is given by k; Boltzmann constant is given by n; and the preset humidity acceleration index is given by n.

[0034] Based on the time conversion factor, the data acquisition time point is converted into a time parameter value.

[0035] As a preferred embodiment, the weighted integration of the environmental temperature and humidity compensation parameters and the current transformer aging compensation parameters to obtain the current transformer signal compensation parameters includes:

[0036] Based on the preset temperature and humidity coupling threshold, the real-time temperature, and the real-time humidity, calculate the temperature and humidity cross-compensation parameters;

[0037] Based on the temperature and humidity cross-compensation parameters, the environmental temperature and humidity compensation parameters and the current transformer aging compensation parameters are weighted and integrated to obtain the current transformer signal compensation parameters.

[0038] The transformer signal compensation parameters are calculated using the following formula:

[0039] K = ω TH ·K1+(1-ω TH )·(1-K2)

[0040] In the formula, K is the current transformer signal compensation parameter; K1 is the ambient temperature and humidity compensation parameter; K2 is the current transformer aging compensation parameter; ω TH These are the parameters for temperature and humidity cross-compensation.

[0041] As a preferred embodiment, the calculation of temperature and humidity cross-compensation parameters based on a preset temperature and humidity coupling threshold, the real-time temperature, and the real-time humidity includes:

[0042] The humidity cross-compensation parameters are calculated using the following formula:

[0043]

[0044] In the formula, ω TH is the humidity cross-compensation parameter; T is the real-time temperature; H is the real-time humidity; C is the preset temperature and humidity coupling threshold; k′ is the preset slope factor.

[0045] As a preferred embodiment, the step of compensating the real-time current output value based on the current transformer signal compensation parameters to obtain the current compensation value of the target current transformer includes:

[0046] The product of the real-time current output value and the current transformer signal compensation parameter is determined as the current compensation value of the target current transformer.

[0047] The current compensation value is calculated using the following formula:

[0048] I correct =K·I raw

[0049] In the formula, I correct I is the current compensation value; K is the transformer signal compensation parameter; I raw This is the real-time current output value.

[0050] As a preferred embodiment, the following steps are adopted: based on the aforementioned reference parameters, an accelerated aging test is performed on the unaged current transformer to solve for the environmental calibration parameters, including:

[0051] Construct an environmental current correlation model;

[0052] Using the reference humidity as the test humidity, several sets of test temperatures are set to conduct accelerated aging tests on the unaged current transformer, obtain the first test current data, and perform parameter fitting on the environmental current correlation model based on the first test current data to obtain temperature calibration parameters.

[0053] Using the reference temperature as the test temperature, several sets of test humidity are set to conduct accelerated aging tests on the unaged current transformer, obtain the second test current data, and perform parameter fitting on the environmental current correlation model based on the second test current data to obtain humidity calibration parameters.

[0054] Several sets of test temperature and humidity combinations are set to conduct accelerated aging tests on the unaged current transformer, obtain third test current data, and perform parameter fitting on the environmental current correlation model based on the third test current data to obtain temperature and humidity cross-calibration parameters.

[0055] The temperature calibration parameter, the humidity calibration parameter, and the temperature-humidity cross-calibration parameter are determined as environmental calibration parameters;

[0056] The expression for the environmental current correlation model is as follows:

[0057] i test =α[i ref (T test -T ref (H) test -H ref )]+i ref

[0058] In the formula, i test α is the test current value; i is the environmental calibration parameter; ref The reference current value is T. test T represents the test temperature. ref For reference temperature; H test For the test humidity; H ref This is for reference humidity.

[0059] As a preferred embodiment, the following steps are adopted: based on the aforementioned reference parameters, an accelerated aging test is performed on the unaged current transformer to solve for the aging calibration parameters, including:

[0060] Construct an aging current model;

[0061] Based on the reference temperature and the reference humidity, an accelerated aging test is conducted on the unaged current transformer, and several aging current values ​​and corresponding aging time points are obtained according to a preset time interval.

[0062] Based on the reference current value, calculate the current difference corresponding to several of the aging current values ​​respectively;

[0063] Based on the time conversion factor, each of the aging time points is converted into aging time parameter values;

[0064] Based on the current difference and the aging time parameter value, the aging current model is fitted with parameters to obtain the initial aging offset and aging calibration parameters.

[0065] The initial aging offset and the aging calibration parameters are determined as aging calibration parameters;

[0066] The expression for the aging current model is as follows:

[0067] Δi(t)=β0+β1·ln(1+t test / τ)

[0068] In the formula, Δi(t) is the current difference; β0 is the initial aging offset; β1 is the aging calibration parameter; t test τ represents the aging time parameter value; τ is the preset lifespan value of the current transformer.

[0069] Accordingly, the present invention provides a current transformer signal compensation device, comprising: a reference data acquisition module, a test module, a real-time data acquisition module, an environmental parameter calculation module, a time-effect parameter calculation module, a compensation parameter calculation module, and a current compensation module;

[0070] The reference data acquisition module is used to acquire reference parameters; wherein, the reference reference parameters include reference temperature, reference humidity and reference current value; the reference current value is the current value output by the unaged current transformer at the reference temperature and the reference humidity.

[0071] The test module is used to conduct accelerated aging tests on unaged current transformers based on the benchmark reference parameters, and to solve for environmental calibration parameters and aging calibration parameters.

[0072] The real-time data acquisition module is used to acquire the real-time current output value, real-time temperature, real-time humidity and data acquisition time of the target current transformer in real time.

[0073] The environmental parameter calculation module is used to calculate environmental temperature and humidity compensation parameters based on the real-time temperature, the real-time humidity, the environmental calibration parameters, and the reference parameters.

[0074] The aging parameter calculation module is used to calculate the current transformer aging compensation parameters based on the aging calibration parameters and the data acquisition time point;

[0075] The compensation parameter calculation module is used to weight and integrate the environmental temperature and humidity compensation parameters and the current transformer aging compensation parameters to obtain the current transformer signal compensation parameters.

[0076] The current compensation module is used to compensate the real-time current output value based on the current transformer signal compensation parameters to obtain the current compensation value of the target current transformer.

[0077] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0078] This invention provides a current transformer signal compensation method, which involves: obtaining reference parameters; conducting accelerated aging tests on an unaged current transformer based on the reference parameters to solve for environmental calibration parameters and aging calibration parameters; acquiring real-time current output value, real-time temperature, real-time humidity, and data acquisition time points of the target current transformer; calculating environmental temperature and humidity compensation parameters based on the real-time temperature, real-time humidity, environmental calibration parameters, and reference parameters; calculating transformer aging compensation parameters based on the aging calibration parameters and data acquisition time points; weighting and integrating the environmental temperature and humidity compensation parameters and the transformer aging compensation parameters to obtain the transformer signal compensation parameters; and compensating the real-time current output value based on the transformer signal compensation parameters to obtain the current compensation value of the target current transformer. This invention pre-sets static environmental calibration parameters and aging calibration parameters based on reference parameters. In real-time applications, the static calibration parameters are dynamically corrected according to the acquired real-time temperature, real-time humidity, and data acquisition time. By calculating the environmental temperature and humidity compensation parameters, the coupling effect between temperature and humidity is considered. By calculating the current transformer aging compensation parameters, the impact of the current transformer's operating time on the output signal is considered. Therefore, by using the current transformer signal compensation parameters generated based on the environmental temperature and humidity compensation parameters and the current transformer aging compensation parameters to compensate for the real-time current output value, more accurate current information that adapts to the actual operating conditions of the current transformer can be obtained, thus improving the compensation accuracy of the current transformer signal. Attached Figure Description

[0079] To more clearly illustrate the technical solution of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0080] Figure 1 A flowchart illustrating one embodiment of the current transformer signal compensation method provided by the present invention;

[0081] Figure 2 This is a flowchart illustrating another embodiment of the current transformer signal compensation method provided by the present invention.

[0082] Figure 3This is a schematic diagram of one embodiment of the current transformer signal compensation device provided by the present invention. Detailed Implementation

[0083] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0084] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0085] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0086] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0087] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0088] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0089] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0090] See Figure 1 To address the problem of low accuracy in current transformer signal compensation in existing technologies, an embodiment of the present invention provides a current transformer signal compensation method, which includes steps 101 to 107, the specific details of which are as follows:

[0091] Step 101: Obtain reference parameters; wherein, the reference parameters include reference temperature, reference humidity and reference current value; the reference current value is the current value output by the unaged current transformer at the reference temperature and the reference humidity.

[0092] In this embodiment of the invention, the reference parameters include reference temperature, reference humidity, and reference current value. The reference temperature and reference humidity are the environmental conditions set for the unaged current transformer when obtaining the reference current value. For example, the reference temperature can be set to 25°C, and the reference humidity can be set to 60%RH. The unaged current transformer is a current transformer whose operating time is less than a preset aging threshold. The current value output by the unaged current transformer under the reference temperature and reference humidity conditions is obtained, and this current value is determined as the reference current value.

[0093] Step 102: Based on the aforementioned reference parameters, conduct accelerated aging tests on the unaged current transformer to solve for the environmental calibration parameters and aging calibration parameters.

[0094] In this embodiment of the invention, accelerated aging tests are conducted on unaged current transformers by setting different test temperatures and humidity levels, and the output current data of the unaged current transformers is acquired at different time periods. Static environmental calibration parameters and time-dependent calibration parameters can be determined through parameter fitting. Specifically, during parameter fitting, a particle swarm optimization algorithm can be used to determine the optimal solution among multiple undetermined calibration parameters.

[0095] As a preferred embodiment, the following steps are adopted: based on the reference parameters, an accelerated aging test is performed on the unaged current transformer to solve for the environmental calibration parameters, including:

[0096] Construct an environmental current correlation model;

[0097] Using the reference humidity as the test humidity, several sets of test temperatures are set to conduct accelerated aging tests on the unaged current transformer, obtain the first test current data, and perform parameter fitting on the environmental current correlation model based on the first test current data to obtain temperature calibration parameters.

[0098] Using the reference temperature as the test temperature, several sets of test humidity are set to conduct accelerated aging tests on the unaged current transformer, obtain the second test current data, and perform parameter fitting on the environmental current correlation model based on the second test current data to obtain humidity calibration parameters.

[0099] Several sets of test temperature and humidity combinations are set to conduct accelerated aging tests on the unaged current transformer, obtain third test current data, and perform parameter fitting on the environmental current correlation model based on the third test current data to obtain temperature and humidity cross-calibration parameters.

[0100] The temperature calibration parameter, the humidity calibration parameter, and the temperature-humidity cross-calibration parameter are determined as environmental calibration parameters;

[0101] The expression for the environmental current correlation model is as follows:

[0102] i test =α[i ref (T test -T ref (H) test -H ref )]+i ref

[0103] In the formula, i test α is the test current value; i is the environmental calibration parameter; ref The reference current value is T. test T represents the test temperature. ref For reference temperature; H test For the test humidity; H ref Reference humidity

[0104] In this embodiment of the invention, static environmental calibration parameters are obtained by conducting accelerated aging tests on unaged current transformers. Specifically, an environmental current correlation model is first constructed to determine the correlation between environmental calibration parameters and the current values ​​of the current transformers. Environmental calibration parameters include temperature calibration parameters, humidity calibration parameters, and temperature-humidity cross-calibration parameters. Based on reference humidity and reference humidity, different test temperatures and humidity levels can be set to obtain test current data output by the unaged current transformers under different environmental conditions. Then, the environmental current correlation model is fitted with parameters to obtain the corresponding environmental calibration parameters.

[0105] For temperature calibration parameters, while maintaining a reference humidity level, the temperature conditions are varied to obtain first-test current data under different temperature conditions. Based on different test temperatures and their corresponding first-test current data, the environmental current correlation model can be curve-fitted to solve for the temperature calibration parameters. In this case, the environmental current correlation model can be expressed as:

[0106] i test =α T [i ref (T test -T ref )]+i ref

[0107] Where, α T These are the temperature calibration parameters.

[0108] For temperature calibration parameters, while maintaining the reference temperature, humidity conditions are varied to obtain second test current data under different humidity conditions. Based on different test humidity levels and their corresponding second test current data, the environmental current correlation model can be curve-fitted to solve for the humidity calibration parameters. In this case, the environmental current correlation model can be expressed as:

[0109] i test =α H [i ref (H test -H ref )]+i ref

[0110] Where, α H These are humidity calibration parameters.

[0111] For temperature and humidity cross-calibration parameters, both temperature and humidity conditions are changed simultaneously to obtain third test current data under different temperature and humidity conditions. Based on different test temperatures, humidity levels, and third test current data, the environmental current correlation model can be curve-fitted to solve for the temperature and humidity cross-calibration parameters. In this case, the environmental current correlation model can be expressed as:

[0112] i test =α TH [i ref (T test -T ref (H) test -H ref )]+i ref

[0113] Where, α TH These are parameters for temperature and humidity cross-calibration.

[0114] As a preferred embodiment, the following steps are adopted: based on the reference parameters, an accelerated aging test is performed on the unaged current transformer to solve for the aging calibration parameters, including:

[0115] Construct an aging current model;

[0116] Based on the reference temperature and the reference humidity, an accelerated aging test is conducted on the unaged current transformer, and several aging current values ​​and corresponding aging time points are obtained according to a preset time interval.

[0117] Based on the reference current value, calculate the current difference corresponding to several of the aging current values ​​respectively;

[0118] Based on the time conversion factor, each of the aging time points is converted into aging time parameter values;

[0119] Based on the current difference and the aging time parameter value, the aging current model is fitted with parameters to obtain the initial aging offset and aging calibration parameters.

[0120] The initial aging offset and the aging calibration parameters are determined as aging calibration parameters;

[0121] The expression for the aging current model is as follows:

[0122] Δi(t)=β0+β1·ln(1+t test / τ)

[0123] In the formula, Δi(t) is the current difference; β0 is the initial aging offset; β1 is the aging calibration parameter; t test τ represents the aging time parameter value; τ is the preset lifespan value of the current transformer.

[0124] In this embodiment of the invention, static aging calibration parameters are obtained by conducting accelerated aging tests on unaged current transformers. Specifically, an aging current model is first constructed to determine the correlation between the aging calibration parameters and the current transformer current value. The aging calibration parameters include the initial aging offset and the aging calibration parameters. Under reference humidity and ambient conditions, the aging current values ​​output by the unaged current transformer are obtained at different time periods, and then the aging current model is fitted with parameters to obtain the corresponding aging calibration parameters.

[0125] The expression for the aging current model is: αi(t)=β0+β1·ln(1+t) test / τ), where τ is the preset lifespan value of the current transformer, which can be 90% of the lifespan of the same model of current transformer. The lifespan of the current transformer can be obtained from the preset database. Under the environmental conditions of reference humidity and reference humidity, the aging current values ​​corresponding to different aging time points can be obtained according to the preset time interval. The aging time points collected at this time are the actual operating time of the current transformer. The aging time points can be converted into aging time parameter values ​​through the time conversion factor for parameter fitting. The method of time conversion using the time conversion factor can refer to the method in subsequent step 105. Since the constructed aging current model reflects the correlation between the current difference and the aging time parameter value, after collecting the aging current values ​​corresponding to different aging time points, it is necessary to calculate the current difference corresponding to each aging current value with the help of the reference current value. After the collected data is processed as described above, the aging current model is curve fitted based on the current difference and the aging time parameter value to solve for the initial aging offset and aging calibration parameters.

[0126] Step 103: Real-time acquisition of the target current transformer's real-time current output value, real-time temperature, real-time humidity, and data acquisition time.

[0127] In this embodiment of the invention, in practical application, a temperature sensor is attached to the surface of the target current transformer's contact cable side housing, and a humidity sensor is built into the target current transformer housing. This allows for accurate acquisition of the real-time temperature and humidity corresponding to the target current transformer's output current value. From a preset database, the actual operating time of the target current transformer when outputting the real-time current value can be obtained and determined as the data acquisition time point.

[0128] Step 104: Calculate the environmental temperature and humidity compensation parameters based on the real-time temperature, the real-time humidity, the environmental calibration parameters, and the reference parameters.

[0129] As a preferred embodiment, based on the real-time temperature, the real-time humidity, the environmental calibration parameters, and the reference parameters, the environmental temperature and humidity compensation parameters are calculated, including:

[0130] The temperature calibration parameters, humidity calibration parameters, and temperature-humidity cross-calibration parameters are determined from the aging calibration parameters.

[0131] The reference temperature and reference humidity are determined from the aforementioned reference parameters;

[0132] Based on the real-time temperature, the real-time humidity, the temperature calibration parameter, the humidity calibration parameter, the temperature and humidity cross-calibration parameter, the reference temperature, and the reference humidity, the environmental temperature and humidity compensation parameters are calculated using the following formula:

[0133] K1=1+α T (TT ref )+α H (HH ref )+α TH (TT ref (HH) ref )

[0134] In the formula, K1 is the environmental temperature and humidity compensation parameter; α T For temperature calibration parameters; α H For humidity calibration parameters; α TH These are the cross-calibration parameters for temperature and humidity; T is the real-time temperature; H is the real-time humidity; T ref For reference temperature; H ref This is for reference humidity.

[0135] In this embodiment of the invention, real-time temperature and humidity, acquired simultaneously with the real-time current output value, can correct static environmental calibration parameters, resulting in a dynamic environmental coefficient used to correct the real-time current output value, i.e., environmental temperature and humidity compensation parameters. Using a reference parameter as a benchmark, the differences between the real-time temperature and humidity and the reference reference parameter are calculated, and the temperature calibration parameter, humidity calibration parameter, and temperature-humidity cross-calibration parameter are numerically adjusted to obtain dynamic environmental temperature and humidity compensation parameters related to the real-time data.

[0136] Step 105: Calculate the current transformer aging compensation parameters based on the time calibration parameters and the data acquisition time point.

[0137] As a preferred embodiment, the aging compensation parameters of the current transformer are calculated based on the aging calibration parameters and the data acquisition time point, including:

[0138] The initial aging offset and aging calibration parameters are determined in the aging calibration parameters;

[0139] Based on the time conversion factor, the data acquisition time points are converted into time parameter values;

[0140] Based on the initial aging offset, the aging calibration parameters, and the time parameter value, the current transformer aging compensation parameters are calculated using the following formula:

[0141] K2=β0+β1·ln(1+t / τ)

[0142] In the formula, K2 is the current transformer aging compensation parameter; β0 is the initial aging offset; β1 is the aging calibration parameter; t is the time parameter value; and τ is the preset current transformer life value.

[0143] The time parameter value is calculated using the following formula:

[0144] t = AF·t h

[0145] In the formula, t is the time parameter value; AF is the time conversion factor; t h This refers to the time point when the data was collected.

[0146] In this embodiment of the invention, the data acquisition time point obtained simultaneously with the acquisition of real-time current output values ​​can correct static aging calibration parameters, resulting in a dynamic aging coefficient used to correct the real-time current output values, i.e., the transformer aging compensation parameter. The calculation of the transformer aging compensation parameter requires the aging calibration parameters, time parameter values, and a preset current transformer lifespan value. The preset current transformer lifespan value can be taken as 90% of the lifespan of a current transformer of the same model as the target current transformer. The time parameter value is obtained by converting the data acquisition time point. The method for data conversion is to multiply the data acquisition time point by a time conversion factor. The time conversion factor can be a preset fixed value or dynamically change based on the real-time data corresponding to the target current transformer.

[0147] As a preferred embodiment, the data acquisition time point is converted into a time parameter value based on a time conversion factor, including:

[0148] Obtain the activation energy of the transformer core of the target current transformer;

[0149] Determine the temperature calibration parameters and humidity calibration parameters from the aging calibration parameters;

[0150] Based on the real-time temperature, the real-time humidity, the activation energy of the transformer core, the temperature calibration parameters, and the humidity calibration parameters, the time conversion factor is calculated using the following formula:

[0151]

[0152] In the formula, AF is the time conversion factor; T is the real-time temperature; H is the real-time humidity; T ref For temperature calibration parameters; H ref For humidity calibration parameters; E a The current transformer core activation energy is given by k; Boltzmann constant is given by n; and the preset humidity acceleration index is given by n.

[0153] Based on the time conversion factor, the data acquisition time point is converted into a time parameter value.

[0154] In this embodiment of the invention, the time conversion factor is set to dynamically change according to the real-time data of the target current transformer, which can better adapt to the real-time operating conditions of the target current transformer. Therefore, based on the collected real-time temperature, real-time humidity, and the activation energy of the transformer core of the target current transformer, combined with the reference parameters obtained from pre-monitoring, the dynamic time conversion factor can be obtained using the above formula.

[0155] Step 106: Weight and integrate the ambient temperature and humidity compensation parameters and the current transformer aging compensation parameters to obtain the current transformer signal compensation parameters.

[0156] As a preferred embodiment, the environmental temperature and humidity compensation parameters and the current transformer aging compensation parameters are weighted and integrated to obtain the current transformer signal compensation parameters, including:

[0157] Based on the preset temperature and humidity coupling threshold, the real-time temperature, and the real-time humidity, calculate the temperature and humidity cross-compensation parameters;

[0158] Based on the temperature and humidity cross-compensation parameters, the environmental temperature and humidity compensation parameters and the current transformer aging compensation parameters are weighted and integrated to obtain the current transformer signal compensation parameters.

[0159] The transformer signal compensation parameters are calculated using the following formula:

[0160] K = ω TH ·K1+(1-ω TH )·(1-K2)

[0161] In the formula, K is the current transformer signal compensation parameter; K1 is the ambient temperature and humidity compensation parameter; K2 is the current transformer aging compensation parameter; ω TH These are the parameters for temperature and humidity cross-compensation.

[0162] In this embodiment of the invention, after determining the dynamic environmental temperature and humidity compensation parameters and the transformer aging compensation parameters, a transformer signal compensation parameter for compensating the transformer current output value can be obtained by weighting and integrating the two compensation parameters, thus facilitating subsequent signal compensation operations. Specifically, using dynamic weighting to integrate the environmental temperature and humidity compensation parameters and the transformer aging compensation parameters better adapts to the real-time operating conditions of the target current transformer, thereby improving the accuracy of current compensation for the transformer current value. Therefore, dynamic temperature and humidity cross-compensation parameters can be set for weighted integration.

[0163] As a preferred embodiment, based on a preset temperature and humidity coupling threshold, the real-time temperature, and the real-time humidity, temperature and humidity cross-compensation parameters are calculated, including:

[0164] The humidity cross-compensation parameters are calculated using the following formula:

[0165]

[0166] In the formula, ω TH is the humidity cross-compensation parameter; T is the real-time temperature; H is the real-time humidity; C is the preset temperature and humidity coupling threshold; k′ is the preset slope factor.

[0167] In this embodiment of the invention, the humidity cross-compensation parameter is dynamically adjusted based on the real-time data of the target current transformer, which better adapts to the real-time operating conditions of the target current transformer. Therefore, by collecting real-time temperature and humidity, as well as preset temperature and humidity coupling thresholds and slope factors, the dynamic humidity cross-compensation parameter can be calculated according to the above formula. The temperature and humidity coupling threshold is determined based on the region; for example, in the southern coastal region, the temperature and humidity coupling threshold can be set as: 25℃ × 60%RH = 1500.

[0168] Step 107: Compensate the real-time current output value based on the current transformer signal compensation parameters to obtain the current compensation value of the target current transformer.

[0169] As a preferred embodiment, the real-time current output value is compensated based on the current transformer signal compensation parameters to obtain the current compensation value of the target current transformer, including:

[0170] The product of the real-time current output value and the current transformer signal compensation parameter is determined as the current compensation value of the target current transformer.

[0171] The current compensation value is calculated using the following formula:

[0172] I correct =K·I raw

[0173] In the formula, I correct I is the current compensation value; K is the transformer signal compensation parameter; I raw This is the real-time current output value.

[0174] In this embodiment of the invention, after calculating the dynamic current transformer signal compensation parameters that take into account the environmental conditions of temperature and humidity and the degree of device aging, the real-time current output value of the target current transformer is compensated based on the current transformer signal compensation parameters, which can yield a more accurate current compensation value.

[0175] In this embodiment of the invention, since the real-time output current signal may contain noise, a filter can be added to filter the current compensation value to obtain the final output signal, thereby improving signal quality. The current compensation value obtained after current compensation from the current transformer contains more accurate current information, which can provide more accurate data for partial discharge detection in cable online monitoring systems, thereby reducing misjudgments in cable online monitoring systems.

[0176] See Figure 2 This is a flowchart illustrating another embodiment of the current transformer signal compensation method provided by the present invention. Based on accelerated aging tests and particle swarm optimization algorithms, static environmental calibration parameters and aging calibration parameters can be pre-determined; when the current transformer outputs a real-time current output value I... raw The system uses a temperature sensor to obtain the real-time temperature T and a humidity sensor to obtain the real-time humidity H, and collects the current data acquisition time point. Based on the real-time temperature T and real-time humidity H, the environmental calibration parameters are corrected, and the dynamic environmental temperature and humidity compensation parameter K1 is calculated using the control system. Based on the data acquisition time point, the aging calibration parameters are corrected, and the dynamic current transformer signal compensation parameter K2 is calculated. Then, the environmental temperature and humidity compensation parameter K1 and the current transformer signal compensation parameter K2 are integrated to obtain the current transformer signal compensation parameter K. The current transformer signal compensation parameter K is used to adjust the real-time current output value I. raw Compensation is performed to obtain the current compensation value I. correct Finally, the current compensation value I is adjusted using a filter. correct The filter is then applied, and the filtered results are transmitted to the host computer / protection device to provide more accurate data for the cable online monitoring system.

[0177] Implementing the above embodiments has the following effects:

[0178] This invention provides a current transformer signal compensation method, which involves: obtaining reference parameters; conducting accelerated aging tests on an unaged current transformer based on the reference parameters to solve for environmental calibration parameters and aging calibration parameters; acquiring real-time current output value, real-time temperature, real-time humidity, and data acquisition time points of the target current transformer; calculating environmental temperature and humidity compensation parameters based on the real-time temperature, real-time humidity, environmental calibration parameters, and reference parameters; calculating transformer aging compensation parameters based on the aging calibration parameters and data acquisition time points; weighting and integrating the environmental temperature and humidity compensation parameters and the transformer aging compensation parameters to obtain the transformer signal compensation parameters; and compensating the real-time current output value based on the transformer signal compensation parameters to obtain the current compensation value of the target current transformer. This invention pre-sets static environmental calibration parameters and aging calibration parameters based on reference parameters. In real-time applications, the static calibration parameters are dynamically corrected according to the acquired real-time temperature, real-time humidity, and data acquisition time. By calculating the environmental temperature and humidity compensation parameters, the coupling effect between temperature and humidity is considered. By calculating the current transformer aging compensation parameters, the impact of the current transformer's operating time on the output signal is considered. Therefore, by using the current transformer signal compensation parameters generated based on the environmental temperature and humidity compensation parameters and the current transformer aging compensation parameters to compensate for the real-time current output value, more accurate current information that adapts to the actual operating conditions of the current transformer can be obtained, thus improving the compensation accuracy of the current transformer signal.

[0179] like Figure 3 As shown, based on the above method embodiments, corresponding apparatus embodiments are provided;

[0180] One embodiment of the present invention provides a current transformer signal compensation device, including: a reference data acquisition module, a test module, a real-time data acquisition module, an environmental parameter calculation module, a time-effect parameter calculation module, a compensation parameter calculation module, and a current compensation module;

[0181] The reference data acquisition module is used to acquire reference parameters; wherein, the reference reference parameters include reference temperature, reference humidity and reference current value; the reference current value is the current value output by the unaged current transformer at the reference temperature and the reference humidity.

[0182] The test module is used to conduct accelerated aging tests on unaged current transformers based on the benchmark reference parameters, and to solve for environmental calibration parameters and aging calibration parameters.

[0183] The real-time data acquisition module is used to acquire the real-time current output value, real-time temperature, real-time humidity and data acquisition time of the target current transformer in real time.

[0184] The environmental parameter calculation module is used to calculate environmental temperature and humidity compensation parameters based on the real-time temperature, the real-time humidity, the environmental calibration parameters, and the reference parameters.

[0185] The aging parameter calculation module is used to calculate the current transformer aging compensation parameters based on the aging calibration parameters and the data acquisition time point;

[0186] The compensation parameter calculation module is used to weight and integrate the environmental temperature and humidity compensation parameters and the current transformer aging compensation parameters to obtain the current transformer signal compensation parameters.

[0187] The current compensation module is used to compensate the real-time current output value based on the current transformer signal compensation parameters to obtain the current compensation value of the target current transformer.

[0188] It is understood that the above-described device embodiments correspond to the method embodiments of the present invention, and can implement the current transformer signal compensation method provided by any of the above-described method embodiments of the present invention.

[0189] It should be noted that the device embodiments described above are merely illustrative, and some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Furthermore, in the accompanying drawings of the device embodiments provided by this invention, the connection relationships between modules indicate that they have communication connections, which can specifically be implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement this without any creative effort.

[0190] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A current transformer signal compensation method, characterized by, The method comprises the following steps: obtaining a reference parameter; wherein the reference parameter comprises a reference temperature, a reference humidity and a reference current value; the reference current value is a current value output by an unaged current transformer at the reference temperature and the reference humidity; based on the reference parameter, performing an accelerated aging test on the unaged current transformer to obtain an environmental calibration parameter and an aging calibration parameter; obtaining a real-time current output value, a real-time temperature, a real-time humidity and a data acquisition time point of a target current transformer in real time; based on the real-time temperature, the real-time humidity, the environmental calibration parameter and the reference parameter, calculating an environmental temperature and humidity compensation parameter; based on the aging calibration parameter and the data acquisition time point, calculating a current transformer aging compensation parameter; weighting and integrating the environmental temperature and humidity compensation parameter and the current transformer aging compensation parameter to obtain a current transformer signal compensation parameter; based on the current transformer signal compensation parameter, compensating the real-time current output value to obtain a current compensation value of the target current transformer.

2. The current transformer signal compensation method of claim 1, wherein, The method comprises the following steps: determining a temperature calibration parameter, a humidity calibration parameter and a temperature and humidity cross calibration parameter in the aging calibration parameter; determining a reference temperature and a reference humidity in the reference parameter; based on the real-time temperature, the real-time humidity, the temperature calibration parameter, the humidity calibration parameter, the temperature and humidity cross calibration parameter, the reference temperature and the reference humidity, calculating an environmental temperature and humidity compensation parameter by using the following formula: K1 = 1 + a T (T-T ref ) + a H (H-H ref ) + a TH (T-T ref ) (H-H ref ) In the formula, K1 is an environmental temperature and humidity compensation parameter; α T is a temperature calibration parameter; α H is a humidity calibration parameter; α TH is a temperature and humidity cross calibration parameter; T is a real-time temperature; H is a real-time humidity; T ref is a reference temperature; H ref is a reference humidity.

3. The current transformer signal compensation method of claim 1, wherein, The method comprises the following steps: determining an initial aging offset and an aging calibration parameter in the aging calibration parameter; based on a time conversion factor, converting the data acquisition time point into a time parameter value; based on the initial aging offset, the aging calibration parameter and the time parameter value, calculating a current transformer aging compensation parameter by using the following formula: K2=β0+β1·ln(1+t / τ) In the formula, K2 is the current transformer aging compensation parameter; β0 is the initial aging offset; β1 is the aging calibration parameter; t is the time parameter value; τ is a preset current transformer service life value; wherein the time parameter value is calculated by using the following formula: t = AF-t h where t is a time parameter value; AF is a time conversion factor; t h is a data collection time point.

4. The current transformer signal compensation method of claim 3, wherein, The method comprises the following steps: obtaining a current transformer magnetic core activation energy of the target current transformer; determining a temperature calibration parameter and a humidity calibration parameter in the aging calibration parameter; based on the real-time temperature, the real-time humidity, the current transformer magnetic core activation energy, the temperature calibration parameter and the humidity calibration parameter, calculating a time conversion factor by using the following formula: In the formula, AF is a time conversion factor; T is a real-time temperature; H is a real-time humidity; T ref is a temperature calibration parameter; H ref is a humidity calibration parameter; E a is an activation energy of a magnetic core of a transformer; k is a Boltzmann constant; and n is a preset humidity acceleration index. based on the time conversion factor, converting the data acquisition time point into a time parameter value.

5. The current transformer signal compensation method of claim 1, wherein, The method comprises the following steps: Based on the preset temperature and humidity coupling threshold, the real-time temperature and the real-time humidity, a temperature and humidity cross compensation parameter is calculated; Based on the temperature and humidity cross compensation parameter, the environmental temperature and humidity compensation parameter and the mutual inductor aging compensation parameter are weighted and integrated to obtain a mutual inductor signal compensation parameter; Wherein, the mutual inductor signal compensation parameter is calculated by the following formula: K = ω TH • K1+ (1 - ω TH ) · (1 - K2) In the formula, K is a mutual inductor signal compensation parameter; K1 is an environmental temperature and humidity compensation parameter; K2 is a mutual inductor aging compensation parameter; ω TH is a temperature and humidity cross compensation parameter.

6. The current transformer signal compensation method of claim 5, wherein, The calculation of the temperature and humidity cross compensation parameter based on the preset temperature and humidity coupling threshold, the real-time temperature and the real-time humidity comprises: The humidity cross compensation parameter is calculated by the following formula: In the formula, ω TH is a humidity cross compensation parameter; T is a real-time temperature; H is a real-time humidity; C is a preset temperature and humidity coupling threshold; k ′ is a preset slope factor.

7. The current transformer signal compensation method of claim 1, wherein, The compensation of the real-time current output value based on the mutual inductor signal compensation parameter to obtain the current compensation value of the target current transformer comprises: The product of the real-time current output value and the mutual inductor signal compensation parameter is determined as the current compensation value of the target current transformer; Wherein, the current compensation value is calculated by the following formula: I correct = K - I raw In the formula, I correct is the current compensation value; K is the mutual inductor signal compensation parameter; I raw is the real-time current output value.

8. The current transformer signal compensation method of claim 1, wherein, The following steps are used to perform an accelerated aging test on the non-aging current transformer based on the reference parameter to solve the environmental calibration parameter, comprising: An environmental current correlation model is constructed; The reference humidity is set as the test humidity, and a plurality of test temperatures are set to perform an accelerated aging test on the non-aging current transformer to obtain first test current data, and the environmental current correlation model is parameter fitted based on the first test current data to obtain a temperature calibration parameter; The reference temperature is set as the test temperature, and a plurality of test humidities are set to perform an accelerated aging test on the non-aging current transformer to obtain second test current data, and the environmental current correlation model is parameter fitted based on the second test current data to obtain a humidity calibration parameter; A plurality of test temperature and humidity combinations are set to perform an accelerated aging test on the non-aging current transformer to obtain third test current data, and the environmental current correlation model is parameter fitted based on the third test current data to obtain a temperature and humidity cross calibration parameter; The temperature calibration parameter, the humidity calibration parameter and the temperature and humidity cross calibration parameter are determined as the environmental calibration parameter; Wherein, the expression of the environmental current correlation model is: i test = a[i ref (T test -T ref )(H test -H ref )] + i ref wherein i test is the test current value; a is the environmental calibration parameter; i ref is the reference current value; T test is the test temperature; T ref is the reference temperature; H test is the test humidity; H ref is the reference humidity.

9. The current transformer signal compensation method of claim 1, wherein, The following steps are used to perform an accelerated aging test on the non-aging current transformer based on the reference parameter to solve the aging calibration parameter, comprising: An aging current model is constructed; Based on the reference temperature and the reference humidity, an accelerated aging test is performed on the non-aging current transformer, and a plurality of aging current values and corresponding aging time points are obtained according to a preset time interval; Based on the reference current value, a plurality of current difference values corresponding to the aging current values are calculated; According to a time conversion factor, each aging time point is converted into an aging time parameter value; Based on the current difference value and the aging time parameter value, the aging current model is parameter fitted to obtain an initial aging offset and an aging calibration parameter; The initial aging offset and the aging calibration parameter are determined as the aging calibration parameter; Wherein, the expression of the aging current model is: Δi(t) = β0+ β1·ln(l + t test / τ) In the formula, Δi(t) is a current difference value; β0 is an initial aging offset; β1 is an aging calibration parameter; t test is an aging time parameter value; and τ is a preset current transformer life value.

10. A current transformer signal compensation device, characterized by, Comprise: The reference data acquisition module, the test module, the real-time data acquisition module, the environmental parameter calculation module, the aging parameter calculation module, the compensation parameter calculation module and the current compensation module; The reference data acquisition module is configured to acquire a reference parameter; the reference parameter includes a reference temperature, a reference humidity and a reference current value; the reference current value is a current value output by an unaged current transformer at the reference temperature and the reference humidity; The test module is configured to perform an accelerated aging test on an unaged current transformer based on the reference parameter, and solve an environmental calibration parameter and an aging calibration parameter; The real-time data acquisition module is configured to acquire a real-time current output value, a real-time temperature, a real-time humidity and a data acquisition time point of a target current transformer in real time; The environmental parameter calculation module is configured to calculate an environmental temperature and humidity compensation parameter based on the real-time temperature, the real-time humidity, the environmental calibration parameter and the reference parameter; The aging parameter calculation module is configured to calculate a current transformer aging compensation parameter based on the aging calibration parameter and the data acquisition time point; The compensation parameter calculation module is configured to weight and integrate the environmental temperature and humidity compensation parameter and the current transformer aging compensation parameter to obtain a current transformer signal compensation parameter; The current compensation module is configured to compensate the real-time current output value based on the current transformer signal compensation parameter to obtain a current compensation value of the target current transformer.

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