On-load test method and device, electronic equipment and storage medium

Abstract

The invention discloses an on-load test method and device, electronic equipment and a storage medium. The method comprises the following steps: acquiring actual secondary current of current transformers in a bus protection device, a transformer protection device and a line protection device; the actual secondary current is measured by a phase voltammeter; judging whether the transformation ratio and polarity of the current transformers in the bus protection device, the transformer protection device and the line protection device have errors or not according to the amplitude and phase of the actual secondary current of the current transformers in the bus protection device, the transformer protection device and the line protection device, and obtaining an analysis result; and finally, generating an analysis report according to an analysis result. By means of the method, the safety and stability of the electric power system can be improved, the efficiency and accuracy of on-load testing work can be improved, and powerful support is provided for rapid development of the electric power system.

Description

Technical Field

[0001] The present invention relates to the technical field of electric power grid, and in particular to a load testing method, device, electronic equipment and storage medium. Background Art

[0002] Load testing refers to the process of verifying the secondary circuit of the protection device by measuring the actual load current and working voltage after the power system equipment is put into operation to ensure its correctness and reliability. This process is particularly important after the substation is newly built or overhauled, because it can ensure that the action logic and performance of the protection device in actual operation meet the design requirements, thereby preventing the equipment from malfunctioning or refusing to operate, and ensuring the safe and stable operation of the power system. Although the importance of load testing is self-evident, it faces many bottlenecks and challenges in actual operation.

[0003] The existing load test includes the design of a double-clamp digital phase volt-ampere meter that is handheld and easy to operate, but it requires multiple points of time-consuming and labor-intensive form editing and data recording. In addition, in the test of complex circuits, it is necessary to rely on the professional knowledge and skills of personnel to accurately use and interpret the test results, which limits the accuracy of the test results. Summary of the invention

[0004] The present invention provides a load testing method, device, electronic equipment and storage medium to adapt to complex and changeable power systems and improve the efficiency and accuracy of load testing.

[0005] According to one aspect of the present invention, there is provided a load testing method, comprising:

[0006] Obtaining the actual secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device; the actual secondary current is measured by a phase volt-ampere meter;

[0007] According to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device, and the analysis result is obtained;

[0008] Generate an analysis report based on the analysis results.

[0009] Optionally, according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device, and the analysis result is obtained, including:

[0010] Obtain the primary current and transformation ratio of the current transformer in the busbar protection device, transformer protection device and line protection device;

[0011] According to the primary current and transformation ratio of the current transformer in the busbar protection device, transformer protection device and line protection device, the power flow calculates the amplitude and phase of the standard secondary current of the current transformer in the busbar protection device, transformer protection device and line protection device through the power angle relationship method;

[0012] According to whether the difference between the amplitude of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device and the amplitude of the standard secondary current exceeds a preset threshold, it is judged whether there is a transformation ratio error in the current transformer;

[0013] Whether there is a polarity error in the current transformer is determined based on whether the difference between the phase of the actual secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device and the phase of the standard secondary current exceeds a preset threshold.

[0014] Optionally, according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device, and the analysis result is obtained, including:

[0015] Calculate the differential current on both sides of the line according to the actual secondary current of the current transformer on both sides of the line power supply end and the output end;

[0016] According to whether the differential current on both sides of the line exceeds a preset threshold, it is determined whether there is a polarity or ratio error in the current transformer at the line.

[0017] Optionally, according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device, and the analysis result is obtained, including:

[0018] According to the installation type of the current transformer described in the transformer protection device, various types of differential currents are calculated according to the principles of longitudinal differential, phase differential, side differential, zero sequence differential and bushing differential current;

[0019] Based on whether the differential currents of various types are within the standard range, determine whether there are polarity or ratio errors in the current transformers on each side of the main transformer.

[0020] Optionally, according to the installation type of the current transformer in the transformer protection device, before calculating various differential currents according to the principles of longitudinal differential, phase differential, side differential, zero sequence differential and bushing differential current, the following is further included:

[0021] According to the rated voltage, rated capacity and rated current of the main transformer and the transformation ratio and connection mode of the current transformers on each side, phase correction and balance coefficient compensation are performed on the current on the high-voltage side of the main transformer.

[0022] Optionally, according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device, and the analysis result is obtained, including:

[0023] According to the actual secondary current of the current transformer of each branch at the bus, the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current are calculated respectively;

[0024] According to whether the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current exceed the corresponding standard values, it is determined whether the corresponding current transformer has a polarity or ratio error.

[0025] Optionally, after obtaining the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, and before generating the analysis report according to the analysis result, the method further includes:

[0026] Draw a hexagonal vector diagram based on the actual secondary current of the current transformer in the busbar protection device, transformer protection device and line protection device;

[0027] Generate an analysis report based on the analysis results, including:

[0028] An analysis report is generated according to the analysis results and the hexagonal vector diagram.

[0029] According to another aspect of the present invention, there is provided a load testing device, comprising:

[0030] An acquisition module is used to acquire the actual secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device; the actual secondary current is measured and obtained by using a phase volt-ampere meter;

[0031] A judgment module is used to judge whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, and obtain an analysis result;

[0032] The report generation module is used to generate an analysis report according to the analysis results.

[0033] According to another aspect of the present invention, an electronic device is provided, the electronic device comprising:

[0034] at least one processor; and

[0035] a memory communicatively connected to the at least one processor; wherein,

[0036] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the load testing method described in any embodiment of the present invention.

[0037] According to another aspect of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the load testing method described in any embodiment of the present invention when executed.

[0038] The technical solution of the embodiment of the present invention first obtains the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device; the actual secondary current is measured by a phase volt-ampere meter; then, according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device, and the analysis result is obtained; finally, according to the analysis result, an analysis report is generated. Using the above method, on the one hand, it can adapt to the complex and changeable application scenarios in the load test, and can adapt to different voltage levels; on the other hand, through real-time data comparison, chart visualization, and intelligent analysis of results, the digitization and intelligence of the test are realized, which effectively reduces the workload and labor cost investment of the load test, shortens the time of the load test to minutes, and fundamentally improves the efficiency of the load test; on the other hand, the use of load test intelligent analysis software instead of manual operation also guarantees the safety of personnel to a certain extent, can effectively reduce the risk of high-voltage space operation, and form a good high-voltage environment operation protection during the system inspection process, while reducing human errors and ensuring the accuracy and stability of the test results.

[0039] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0041] Figure 1 is a flow chart of a load testing method provided by Embodiment 1 of the present invention;

[0042] Figure 2 A flow chart of a load testing method provided in Embodiment 2 of the present invention;

[0043] Figure 3 A flow chart of a load testing method provided in Embodiment 3 of the present invention;

[0044] Figure 4 A schematic diagram of the structure of a load testing device provided in Embodiment 4 of the present invention;

[0045] Figure 5 It is a structural block diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0047] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] As described in the background technology section, there are many defects in the existing load testing method, which are specifically analyzed as follows:

[0049] (1) Low efficiency: Traditional load testing requires the use of instruments such as phase voltammeters to transfer measurements one by one at multiple screen work locations. Manual editing of forms is required before recording. The recording process is relatively slow, time-consuming, and requires a large number of people, which is inefficient.

[0050] (2) Error-prone: After the traditional load test data is generated, the relay protection personnel need to make manual judgments. However, after long-term operation overnight, the operators are relatively tired, and their attention and energy are at a low point. In addition, the auditors are limited by their professional knowledge and skills, which can easily lead to errors in the audit results. For example, after the protection of a 500kV main transformer was modified, the acceptance personnel did not master the principle of phase differential protection and ignored the risk of polarity reversal. When analyzing the load test data, they did not check the correctness of each current phase, resulting in an unplanned shutdown of the third-level power safety incident.

[0051] (3) High cost: Manual audits require multiple levels of audits by on-site construction personnel, acceptance personnel, team leaders, and specialists, which requires a large amount of human resources and time costs, increasing the company's operating costs. There is also the possibility that human factors may cause a lag in the audit results, resulting in missing the right time to discover hidden dangers, causing unnecessary trouble and losses to the power grid.

[0052] (4) Data deviation: The secondary output analog quantity of the current transformer is located on multiple interval panel cabinets. This decentralized layout makes it impossible to record the positions of the protection panels at the same time, obtain all the secondary analog quantity inputs of the current and compare the data in real time. The instability of the load can easily cause test data deviation.

[0053] In view of the above problems, an embodiment of the present invention provides a load testing method. Specifically, in one embodiment, Figure 1 This is a flow chart of a load test method provided by the first embodiment of the present invention. This embodiment is applicable to the case of power grid load test. The method can be executed by a load test device. The load test device can be implemented in the form of hardware and / or software. The load test device can be configured in a load tester. Figure 1 As shown, the method includes:

[0054] S110, obtaining the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device; the actual secondary current is measured by a phase volt-ampere meter.

[0055] First, the load test method provided in the embodiment of the present invention can be specifically applied to software implementation, that is, a load test analysis software is provided. This step is essentially a process of using a phase voltammeter to measure the current amplitude and phase of the corresponding current transformer (Current transformer, CT) winding, and manually inputting the current amplitude and phase through the software interface. Specifically, the current data measured by the phase voltammeter can be exported in the form of an Excel table and imported into the load test analysis software.

[0056] S120. According to the amplitude and phase of the actual secondary current of the current transformers in the bus protection device, the transformer protection device and the line protection device, determine whether there are errors in the transformation ratio and polarity of the current transformers in the bus protection device, the transformer protection device and the line protection device, and obtain analysis results.

[0057] This step is essentially based on the power system's current flow network, through the actual detected current, to determine the wiring problem of the current transformer. Specifically, those skilled in the art will know that the current transformer, as a current detection device for detecting busbars, transformers, lines and other equipment, has a fixed ratio relationship between the primary and secondary sides of its windings. In addition, in the busbars, transformers and lines, there is also a known correlation between the currents at different positions. Based on these known correlations, the actual secondary current detected by the current transformer can be used to calculate whether these ratio relationships or correlations are correct, thereby inferring whether the current transformer has ratio and polarity errors, and whether it is correctly wired according to the standard ratio and polarity relationship.

[0058] S130. Generate an analysis report based on the analysis results.

[0059] This step is to output the results of the analysis and judgment in the previous step, including whether the transformation ratio and polarity of each current transformer are correct, in the form of an electronic test report for user reference to inspect and repair the corresponding current transformer.

[0060] A load testing method provided in a first embodiment of the present invention first obtains the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device; the actual secondary current is measured by a phase volt-ampere meter; then, according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device, and an analysis result is obtained; finally, an analysis report is generated according to the analysis result. By using the above method, on the one hand, it can adapt to the complex and changeable application scenarios in load testing, and can adapt to different voltage levels; on the other hand, through real-time data comparison, chart visualization, and intelligent analysis of results, the digitization and intelligence of the test are realized, which effectively reduces the workload and labor cost of load testing, shortens the time of load testing to minutes, and fundamentally improves the efficiency of load testing; on the other hand, the use of load testing intelligent analysis software instead of manual work also guarantees the safety of personnel to a certain extent, can effectively reduce the risk of high-voltage space operations, and form a good high-voltage environment operation protection during the system inspection process, while reducing human errors and ensuring the accuracy and stability of the test results. The embodiment of the present invention can improve the efficiency and accuracy of load testing, make data analysis more accurate, make test results more intuitive, improve the safety and stability of the power system, not only meet the complex and changeable main grid transformer test requirements, but also can be applied to the testing of the same type of equipment, and its scope of application is wide, providing strong support for the rapid development of the power system.

[0061] Based on the above embodiment, a variant embodiment of the above embodiment is proposed. It should be noted that in order to make the description concise, only the differences from the above embodiment are described in the variant embodiment.

[0062] In one embodiment, after obtaining the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device in step S110 of the above embodiment, and before generating the analysis report according to the analysis result in step S130, the following steps may be added:

[0063] S121. Draw a hexagonal vector diagram based on the actual secondary current of the current transformer in the busbar protection device, transformer protection device and line protection device.

[0064] The hexagonal vector diagram, also known as the hexagonal diagram, is a method of measuring the current phase using a power meter, and is mainly used for phase detection. The hexagonal diagram can help detect and verify the phase relationship between the three-phase currents of the current transformer, the correctness of the wiring of the power direction relay, whether the current phase of different groups of current transformers in differential protection is correct, and whether the current transformer ratio is correct by representing the projection of the current phasor in a specific coordinate system. This step is the process of automatic drawing through the load test analysis software based on the drawing principle of the hexagonal vector diagram.

[0065] Based on this, the above embodiment step S130, generating an analysis report according to the analysis results, may specifically include: S131, generating an analysis report according to the analysis results and the hexagonal vector diagram.

[0066] In this embodiment, the hexagonal vector diagram is automatically drawn through the load test analysis software, which can not only provide the analysis results of the current transformer ratio and polarity, but also provide the user with a visual hexagonal vector diagram, which is convenient for maintenance personnel to perform manual analysis and judgment at the same time, further ensuring the reliability and accuracy of the load test.

[0067] Figure 2 This is a flow chart of a load testing method provided in Embodiment 2 of the present invention. This embodiment is a refinement of the above embodiment. Specifically, the above embodiment S120 may include:

[0068] Obtain the primary current and transformation ratio of the current transformer in the busbar protection device, transformer protection device and line protection device;

[0069] According to the primary current and transformation ratio of the current transformer in the busbar protection device, transformer protection device and line protection device, the power flow calculates the amplitude and phase of the standard secondary current of the current transformer in the busbar protection device, transformer protection device and line protection device through the power angle relationship method;

[0070] According to whether the difference between the amplitude of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device and the amplitude of the standard secondary current exceeds a preset threshold, it is judged whether there is a transformation ratio error in the current transformer;

[0071] Whether there is a polarity error in the current transformer is determined based on whether the difference between the phase of the actual secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device and the phase of the standard secondary current exceeds a preset threshold.

[0072] For details not yet provided in this embodiment, please refer to Embodiment 1.

[0073] like Figure 2As shown, a load testing method provided by Embodiment 2 of the present invention includes the following steps:

[0074] S210, obtaining the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device; the actual secondary current is measured by a phase volt-ampere meter.

[0075] S220. Draw a hexagonal vector diagram based on the actual secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device.

[0076] S221. Obtain the primary current and transformation ratio of the current transformer in the busbar protection device, the transformer protection device and the line protection device.

[0077] First of all, it should be noted that the load test software provided by the present invention needs to know basic parameters, such as the power equipment conditions, key parameters of the main transformer differential protection, intermediate data and setting standards before analyzing and judging the current transformer ratio and solving problems. This step is the process of inputting the primary current and ratio of the current transformer into the load test software.

[0078] S222. According to the primary current and transformation ratio of the current transformers in the bus protection device, the transformer protection device and the line protection device, the amplitude and phase of the standard secondary current of the current transformers in the bus protection device, the transformer protection device and the line protection device are calculated by the power angle relationship method.

[0079] For busbar protection devices, transformer protection devices and line protection devices, the transformation ratio and polarity of the current transformer can be solved by the power angle relationship method and the flow to calculate the rated secondary current value, that is, the standard secondary current. Specifically, the power angle relationship formula is: According to the power angle relationship, the A-phase CT secondary current amplitude and phase calculated from the power flow data can be used as a reference.

[0080] S223. Determine whether there is a transformation ratio error in the current transformer according to whether the difference between the amplitude of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device and the amplitude of the standard secondary current exceeds a preset threshold.

[0081] S224. Determine whether there is a polarity error in the current transformer according to whether the difference between the phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device and the phase of the standard secondary current exceeds a preset threshold.

[0082] Under normal correct wiring conditions, the three-phase current amplitudes are basically the same; the current phase sequence is phase A ahead of phase B, and phase B ahead of phase C, that is, the phase sequence difference is 120°. Based on this, the measured three-phase current amplitudes and current phase sequences can be checked one by one. Specifically, the error between the actual measured value and the reference value can be judged. If the deviation is greater than 10%, it is considered that there may be a CT polarity or ratio error. Among them, when there is a significant difference in the amplitude of the actual value and the reference value of the secondary current, it may indicate that the CT connector is connected incorrectly, thereby causing a polarity error; when there is a significant difference in the phase, it may indicate that the CT tap is connected incorrectly, thereby causing a ratio error.

[0083] S230. Generate an analysis report based on the analysis results and the hexagonal vector diagram.

[0084] The second embodiment of the present invention provides a load test method, which uses the power angle relationship method to calculate the standard secondary current for comparison, and specifically determines whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, transformer protection device and line protection device according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, transformer protection device and line protection device. Using this method, the transformation ratio and polarity problems of the current transformer in each position can be accurately determined, and it can accurately locate whether it is a joint connection problem or a tap connection problem, providing more accurate, efficient and direct analysis results.

[0085] Figure 3 This is a flow chart of a load testing method provided in Embodiment 3 of the present invention. This embodiment is also a refinement based on the above embodiment. Specifically, the above embodiment S120 may include:

[0086] Calculate the differential current on both sides of the line according to the actual secondary current of the current transformer on both sides of the line power supply end and the output end;

[0087] According to whether the differential current on both sides of the line exceeds the preset threshold, it is judged whether there is a polarity or ratio error in the current transformer at the line.

[0088] Optionally, the above embodiment S120 may further specifically include:

[0089] According to the installation type of current transformer in transformer protection device, various differential currents are calculated according to the principles of longitudinal differential, phase differential, side differential, zero sequence differential and bushing differential current;

[0090] Based on whether the differential currents of various types are within the standard range, determine whether there are polarity or ratio errors in the current transformers on each side of the main transformer.

[0091] Furthermore, according to the installation type of the current transformer in the transformer protection device, before calculating various differential currents according to the principles of longitudinal differential, phase differential, side differential, zero sequence differential and bushing differential current, the following can also be included:

[0092] According to the rated voltage, rated capacity and rated current of the main transformer and the transformation ratio and connection method of the current transformers on each side, the phase correction and balance coefficient compensation are performed on the current on the high-voltage side of the main transformer.

[0093] Optionally, the above embodiment S120 may further specifically include:

[0094] According to the actual secondary current of the current transformer of each branch at the bus, the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current are calculated respectively;

[0095] According to whether the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current exceed the corresponding standard values, it is judged whether the corresponding current transformer has a polarity or ratio error.

[0096] For details not yet provided in this embodiment, please refer to Embodiments 1 and 2.

[0097] like Figure 3 As shown, a load testing method provided by Embodiment 3 of the present invention includes the following steps:

[0098] S310, obtaining the actual secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device; the actual secondary current is measured by a phase volt-ampere meter.

[0099] S320. Draw a hexagonal vector diagram based on the actual secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device.

[0100] S3211. Calculate the differential current on both sides of the line based on the actual secondary current of the current transformer on both sides of the line power supply end and the output end.

[0101] S3212. Determine whether there is a polarity or ratio error in the current transformer at the line based on whether the differential current on both sides of the line exceeds a preset threshold.

[0102] The above S3211 and S3212 are essentially the process of analyzing and judging the correctness of the secondary circuit of the line through the differential current analysis method. Specifically, according to Kirchhoff's current law, at any node of the circuit, the algebraic sum of all currents flowing in and out is zero. Therefore, for the power supply end and the output end of the line, the current difference on both sides should be close to 0. When the difference between the currents on both sides is too large, it means that there is an error in the secondary current circuit, that is, the polarity or transformation ratio of the current transformer at the line is wrong.

[0103] S3221. Perform phase correction and balance coefficient compensation on the current on the high-voltage side of the main transformer according to the rated voltage, rated capacity and rated current of the main transformer and the transformation ratio and wiring method of the current transformers on each side.

[0104] S3222. According to the installation type of the current transformer in the transformer protection device, various types of differential currents are calculated according to the principles of longitudinal differential, phase differential, side differential, zero-sequence differential and bushing differential current.

[0105] S3223. Determine whether there are polarity or ratio errors in the current transformers on each side of the main transformer based on whether the various differential currents are within the standard range.

[0106] The above steps S3221-S3223 are essentially the process of analyzing and judging the correctness of the secondary circuit of the main transformer through the differential current analysis method. Specifically, in this process, it is necessary to select different differential current calculation methods according to the installation type of the current transformer, such as bushing CT or switch CT, including longitudinal differential, phase differential, side differential, zero-sequence differential and bushing differential current. Among them, for the switch CT, it can perform differential current calculations of longitudinal differential, phase differential, side differential and zero-sequence differential; for the bushing CT, the calculation of bushing differential current can be further added. It can be understood that longitudinal differential, phase differential, side differential, zero-sequence differential and bushing differential current are also the basic processes for performing corresponding differential protection. This step is essentially a process of judging abnormal wiring of the current transformer based on the differential protection principle. Among them, the protection scheme of the longitudinal differential is a traditional longitudinal differential protection composed of switch CTs on the high, medium and low sides. The protection scheme of phase differential is a phase differential protection composed of high and medium voltage side switch CT and low voltage side delta winding (bushing) CT. The protection scheme of split side differential is a split side differential protection composed of high and medium voltage side switch CT and common winding bushing CT. The protection scheme of zero sequence differential is a differential protection composed of zero sequence currents on high, medium and low sides. The protection scheme of bushing differential current is a differential protection composed of high bushing, medium bushing and low bushing CT.

[0107] Those skilled in the art will know that due to the different CT ratios and connections on each side of the main transformer, it is necessary to use phase difference adjustment and balance coefficient methods to compensate for phase shift and ratio. The following is an introduction to the specific methods of phase correction and balance coefficient compensation:

[0108] ① Taking the secondary current phase difference compensation of Y->△ as an example, for the connection of △ at 11 o'clock, the phase calculation process of the secondary current loop of the CT on each side of the main transformer should be based on the difference calculated according to the current of each phase, and the Y->△ change should be uniformly used to adjust the differential current balance. The correction method is as follows:

[0109]

[0110] in, is the secondary current of the Y-side CT, It is the current of each phase after correction on the Y side.

[0111] ② Calculation of balance coefficient. Taking the high-voltage side as the benchmark, calculate the balance coefficients of the medium- and low-voltage sides of the main transformer:

[0112]

[0113] Among them, H, M, and L are high, medium, and low voltage sides respectively, and S e U is the rated capacity of the three phases on the high and medium voltage side; 1e is the primary rated voltage; I 1e is the primary rated current; I 2e is the secondary rated current; n LH is the CT ratio. Multiply the phase currents on the medium and low voltage sides by the corresponding balance coefficients to get the phase currents after amplitude compensation.

[0114] S3231. According to the actual secondary current of the current transformer of each branch at the bus, the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current are calculated respectively.

[0115] S3232. Determine whether the corresponding current transformer has a polarity or ratio error based on whether the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current exceed the corresponding standard values.

[0116] The above steps S3231 and S3232 are essentially the process of analyzing and judging the correctness of the secondary circuit of the bus through the differential current analysis method. Specifically, the bus differential current may include the bus large differential circuit and the small differential circuit of each bus section. The bus differential is composed of phase differential elements. The bus large differential refers to the current and absolute value of all branch and segment currents except the bus tie CT; the small differential of each bus section refers to the current and absolute value of all branch currents (including bus ties and segments) on the bus section. The bus large differential is used to judge the faults inside and outside the bus area, and the small differential is used for fault bus selection. When any phase of the calculated values ​​of all differential currents in the bus protection device is greater than the standard value, it can be preliminarily determined that there is a problem with the polarity or transformation ratio of the CT protection circuit. The differential current calculation formula is as follows:

[0117] Large differential current: I d =I1+I2+…+I n ;

[0118] I mother differential current:

[0119] II mother small differential current:

[0120] Among them, I1, I2, …, I nis the primary current value of each branch; I ML is the primary current value of the busbar, and its direction is adjusted according to each section of the busbar; S 11 , S 12 ,...,S 1n S is the position of the main switch of each branch (0 means the switch is open, 1 means it is in action); 21 , S 22 ,...,S 2n It is the position of the II main knife switch of each branch (0 means the knife switch is open, 1 means it is in action).

[0121] S330. Generate an analysis report based on the analysis results and the hexagonal vector diagram.

[0122] A load test method provided in the third embodiment of the present invention uses a differential current analysis method to judge the correctness of the secondary circuit, and specifically determines whether there are errors in the transformation ratio and polarity of the current transformer in the bus protection device, transformer protection device and line protection device according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, transformer protection device and line protection device. Using this method, during the load test process, when the line, main transformer and bus equipment perform differential current calculation according to the differential current analysis method, when the differential current of any phase is greater than 0.04A, it can be preliminarily determined that there is a problem with the polarity or transformation ratio of the CT circuit. The judgment method is simple in principle and responds quickly. It can be complementary to the power angle relationship method in the second embodiment of the present invention to avoid the situation where the load is small and the differential current change is not obvious, ensuring that it can adapt to the complex and changeable application scenarios in the load test.

[0123] Figure 4 This is a schematic diagram of the structure of a load test device provided by the fourth embodiment of the present invention. Figure 4 As shown, the device comprises:

[0124] The acquisition module 100 is used to acquire the actual secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device; the actual secondary current is measured by a phase volt-ampere meter;

[0125] The judgment module 200 is used to judge whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, and obtain an analysis result;

[0126] The report generation module 300 is used to generate an analysis report according to the analysis results.

[0127] In one embodiment, the determination module 200 may include:

[0128] A data acquisition unit, used to acquire the primary current and transformation ratio of the current transformer in the busbar protection device, the transformer protection device and the line protection device;

[0129] A power flow calculation unit, used for power flow calculation of the amplitude and phase of the standard secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device according to the primary current and transformation ratio of the current transformer in the busbar protection device, the transformer protection device and the line protection device through the power angle relationship method;

[0130] A transformation ratio judgment unit, used to judge whether there is a transformation ratio error in the current transformer according to whether the difference between the amplitude of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device and the amplitude of the standard secondary current exceeds a preset threshold;

[0131] The polarity judgment unit is used to judge whether there is a polarity error in the current transformer according to whether the difference between the phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device and the phase of the standard secondary current exceeds a preset threshold.

[0132] In one embodiment, the determination module 200 may include:

[0133] A line differential current calculation unit, used to calculate the differential current on both sides of the line according to the actual secondary current of the current transformer on both sides of the line power supply end and the output end;

[0134] The line CT judgment unit is used to judge whether there is a polarity or ratio error in the current transformer at the line according to whether the differential current on both sides of the line exceeds a preset threshold.

[0135] In one embodiment, the determination module 200 may include:

[0136] The main transformer differential current calculation unit is used to calculate various differential currents according to the installation type of the current transformer in the transformer protection device, according to the longitudinal differential, phase differential, side differential, zero sequence differential and bushing differential current principles;

[0137] The main transformer CT judgment unit is used to determine whether there is a polarity or ratio error in the current transformers on each side of the main transformer according to whether various differential currents are within the standard range.

[0138] Furthermore, the determination module 200 may further include:

[0139] The correction and compensation unit is used to perform phase correction and balance coefficient compensation on the current on the high-voltage side of the main transformer according to the rated voltage, rated capacity and rated current of the main transformer and the transformation ratio and wiring method of the current transformers on each side before calculating various types of differential currents according to the installation type of the current transformer in the transformer protection device and the principles of longitudinal differential, phase differential, side differential, zero-sequence differential and bushing differential current.

[0140] In one embodiment, the determination module 200 may include:

[0141] The bus differential current calculation unit is used to calculate the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current according to the actual secondary current of the current transformer of each branch at the bus;

[0142] The bus CT judgment unit is used to judge whether the corresponding current transformer has polarity or ratio error according to whether the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current exceed the corresponding standard values.

[0143] In one embodiment, the device may further include:

[0144] A drawing unit, for drawing a hexagonal vector diagram according to the actual secondary currents of the current transformers in the bus protection device, the transformer protection device and the line protection device after obtaining the actual secondary currents of the current transformers in the bus protection device, the transformer protection device and the line protection device and before generating the analysis report according to the analysis result;

[0145] Based on this, the report generating module 300 is further used to generate an analysis report according to the analysis results and the hexagonal vector diagram.

[0146] The load testing device provided in the embodiment of the present invention can execute the load testing method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0147] In one embodiment, Figure 5 is a structural block diagram of an electronic device provided by an embodiment of the present invention, such as Figure 5As shown, a schematic diagram of the structure of an electronic device 10 that can be used to implement an embodiment of the present invention is shown. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processing, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0148] like Figure 5 As shown, the electronic device 10 includes at least one processor 11, and a memory connected to the at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 11 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 to the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0149] A number of components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disk, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0150] The processor 11 may be a variety of general and / or special processing components with processing and computing capabilities. Some examples of the processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as the load testing method.

[0151] In some embodiments, the load test method may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the load test method described above may be performed. Alternatively, in other embodiments, the processor 11 may be configured to perform the load test method in any other appropriate manner (e.g., by means of firmware).

[0152] Various implementations of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), load programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0153] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, so that when the computer program is executed by the processor, the functions / operations specified in the flow chart and / or block diagram are implemented. The computer program may be executed entirely on the machine, partially on the machine, partially on the machine and partially on a remote machine as a stand-alone software package, or entirely on a remote machine or server.

[0154] In the context of the present invention, a computer-readable storage medium may be a tangible medium that may contain or store a computer program for use by or in combination with an instruction execution system, device or equipment. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0155] To provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or trackball) through which the user can provide input to the electronic device. Other types of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0156] The systems and techniques described herein may be implemented in a computing system that includes backend components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes frontend components (e.g., a user computer with a graphical user interface or a web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such backend components, middleware components, or frontend components. The components of the system may be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0157] A computing system may include a client and a server. The client and the server are generally remote from each other and usually interact through a communication network. The client and server relationship is generated by computer programs running on the corresponding computers and having a client-server relationship with each other. The server may be a cloud server, also known as a cloud computing server or cloud host, which is a host product in the cloud computing service system to solve the defects of difficult management and weak business scalability in traditional physical hosts and VPS services.

[0158] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0159] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A load testing method, characterized in that: include: Obtain the actual secondary current of the current transformer in the busbar protection device, transformer protection device and line protection device; The actual secondary current is obtained by measuring with a phase volt-ampere meter; According to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device, and the analysis result is obtained; Generate an analysis report based on the analysis results.

2. The load testing method according to claim 1, characterized in that: According to the actual secondary current amplitude and phase of the current transformer in the busbar protection device, transformer protection device and line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the busbar protection device, transformer protection device and line protection device, and the analysis results are obtained, including: Obtain the primary current and transformation ratio of the current transformer in the busbar protection device, transformer protection device and line protection device; According to the primary current and transformation ratio of the current transformer in the busbar protection device, transformer protection device and line protection device, the power flow calculates the amplitude and phase of the standard secondary current of the current transformer in the busbar protection device, transformer protection device and line protection device through the power angle relationship method; According to whether the difference between the amplitude of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device and the amplitude of the standard secondary current exceeds a preset threshold, it is judged whether there is a transformation ratio error in the current transformer; Whether there is a polarity error in the current transformer is determined based on whether the difference between the phase of the actual secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device and the phase of the standard secondary current exceeds a preset threshold.

3. The load testing method according to claim 1, characterized in that: According to the actual secondary current amplitude and phase of the current transformer in the busbar protection device, transformer protection device and line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the busbar protection device, transformer protection device and line protection device, and the analysis results are obtained, including: Calculate the differential current on both sides of the line according to the actual secondary current of the current transformer on both sides of the line power supply end and the output end; According to whether the differential current on both sides of the line exceeds a preset threshold, it is determined whether there is a polarity or ratio error in the current transformer at the line.

4. The load testing method according to claim 1, characterized in that: According to the actual secondary current amplitude and phase of the current transformer in the busbar protection device, transformer protection device and line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the busbar protection device, transformer protection device and line protection device, and the analysis results are obtained, including: According to the installation type of the current transformer described in the transformer protection device, various types of differential currents are calculated according to the principles of longitudinal differential, phase differential, side differential, zero sequence differential and bushing differential current; Based on whether the differential currents of various types are within the standard range, determine whether there are polarity or ratio errors in the current transformers on each side of the main transformer.

5. The load testing method according to claim 4, characterized in that: According to the installation type of the current transformer described in the transformer protection device, before calculating various differential currents according to the principles of longitudinal differential, phase differential, side differential, zero sequence differential and bushing differential current, the following are also included: According to the rated voltage, rated capacity and rated current of the main transformer and the transformation ratio and connection mode of the current transformers on each side, phase correction and balance coefficient compensation are performed on the current on the high-voltage side of the main transformer.

6. The load testing method according to claim 1, characterized in that: According to the actual secondary current amplitude and phase of the current transformer in the busbar protection device, transformer protection device and line protection device, it is judged whether there is an error in the transformation ratio and polarity of the current transformer in the busbar protection device, transformer protection device and line protection device, and the analysis results are obtained, including: According to the actual secondary current of the current transformer of each branch at the bus, the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current are calculated respectively; According to whether the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current exceed the corresponding standard values, it is determined whether the corresponding current transformer has a polarity or ratio error.

7. The load testing method according to claim 1, characterized in that: After obtaining the actual secondary current of the current transformer in the busbar protection device, the transformer protection device and the line protection device, and before generating the analysis report according to the analysis result, the following is also included: Draw a hexagonal vector diagram based on the actual secondary current of the current transformer in the busbar protection device, transformer protection device and line protection device; Generate an analysis report based on the analysis results, including: An analysis report is generated according to the analysis results and the hexagonal vector diagram.

8. A load testing device, characterized in that: include: An acquisition module, used for acquiring actual secondary currents of current transformers in busbar protection devices, transformer protection devices and line protection devices; The actual secondary current is obtained by measuring with a phase volt-ampere meter; A judgment module is used to judge whether there is an error in the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device according to the amplitude and phase of the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, and obtain an analysis result; The report generation module is used to generate an analysis report according to the analysis results.

9. An electronic device, characterized in that: The electronic device comprises: at least one processor; and a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can perform the load testing method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the load testing method according to any one of claims 1 to 7 when executed.

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