Load test method, device, electronic equipment and storage medium

Abstract

The application discloses a kind of with load test method, device, electronic equipment and storage medium.The method includes obtaining the actual secondary current of current transformer in bus protection device, transformer protection device and line protection device;Actual secondary current is obtained using phase voltmeter measurement;Then according to the amplitude and phase of actual secondary current of current transformer in bus protection device, transformer protection device and line protection device, it is judged whether there is error in current transformer ratio and polarity in bus protection device, transformer protection device and line protection device, obtains analysis result;Finally, according to analysis result, generate analysis report.By using the above method, not only the safety and stability of power system can be improved, but also the efficiency and accuracy of load test work can be improved, which provides strong support for the rapid development of power system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power grid, and particularly relates to a load test method and device, electronic equipment and storage medium. BACKGROUND

[0002] Load test refers to a process of verifying the secondary circuit of a protection device through the measurement of actual load current and operating voltage after the power system device is put into operation, so as to ensure its correctness and reliability. This process is particularly important after the completion of new construction or overhaul of a substation, because it can ensure that the action logic and performance of the protection device in actual operation meet the design requirements, thereby preventing device misoperation or refusal to operate and ensuring the safe and stable operation of the power system. Although the importance of load test is self-evident, it still faces many bottlenecks and challenges in actual operation.

[0003] The existing load test includes designing a double clamp digital phase volt-ampere meter as a handheld type, which is easy to operate, but requires multiple points, time-consuming and labor-intensive editing forms and recording data. Moreover, in the test of complex circuits, the professional knowledge and skills of personnel are needed to accurately use and interpret the test results, which limits the accuracy of the test results. SUMMARY

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

[0005] According to an aspect of the present application, a load test method is provided, comprising:

[0006] Obtaining actual secondary currents of current transformers in bus protection devices, transformer protection devices and line protection devices; the actual secondary currents are obtained by measuring with a phase volt-ampere meter;

[0007] According to the amplitudes and phases of the actual secondary currents of the current transformers in the bus protection devices, the transformer protection devices and the line protection devices, it is determined whether there is an error in the transformation ratio and polarity of the current transformers in the bus protection devices, the transformer protection devices and the line protection devices, and an analysis result is obtained;

[0008] According to the analysis result, an analysis report is generated.

[0009] Optionally, according to the amplitudes and phases of the actual secondary currents of the current transformers in the bus protection devices, the transformer protection devices and the line protection devices, it is determined whether there is an error in the transformation ratio and polarity of the current transformers in the bus protection devices, the transformer protection devices and the line protection devices, and an analysis result is obtained, comprising:

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

[0011] According to the primary current and the transformation ratio of the current transformer in the bus protection device, the transformer protection device and the line protection device, the amplitude and the phase of the standard secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device are calculated by the power angle relationship method;

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

[0013] According to whether the difference between the phase of the actual secondary current and the phase of the standard secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device exceeds a preset threshold, it is judged whether the current transformer has a polarity error.

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

[0015] According to the actual secondary currents of the current transformers on both sides of the line power supply end and the output end, the difference current on both sides of the line is calculated;

[0016] According to whether the difference current on both sides of the line exceeds a preset threshold, it is judged whether the current transformer at the line has a polarity or transformation ratio error.

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

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

[0019] According to whether the difference currents are within a standard range, it is determined whether the current transformers on each side of the main transformer have a polarity or transformation ratio error.

[0020] Optionally, before the difference currents of various types are calculated according to the installation type of the current transformer in the transformer protection device, the longitudinal differential, the split-phase differential, the split-side differential, the zero sequence differential and the bushing differential principle, it further includes:

[0021] According to the rated voltage, rated capacity and rated current of the main transformer, and the transformation ratio and wiring mode of each side current transformer, the current on the high voltage side of the main transformer is phase-corrected and balanced coefficient compensated.

[0022] Optionally, 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, it is judged 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, and an 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 difference loop current, the I bus small difference loop current and the II bus small difference loop current are calculated respectively.

[0024] According to whether the bus large difference loop current, the I bus small difference loop current and the II bus small difference loop current exceed the corresponding standard value, it is judged whether there is an error in the polarity or transformation ratio of the corresponding current transformer.

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

[0026] According to the actual secondary current of the current transformer in the bus protection device, transformer protection device and line protection device, a hexagon vector diagram is drawn.

[0027] According to the analysis result, an analysis report is generated, including:

[0028] According to the analysis result and the hexagon vector diagram, an analysis report is generated.

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

[0030] An acquisition module is configured to acquire the actual secondary current of the current transformer in the bus protection device, transformer protection device and line protection device; the actual secondary current is measured by a phase voltmeter.

[0031] A judgment module is configured to judge 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, and obtain an analysis result.

[0032] A report generation module is configured to generate an analysis report according to the analysis result.

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

[0034] at least one processor; and

[0035] a memory communicatively connected with 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 to enable the at least one processor to perform the load test method according to any one of the embodiments of the present application.

[0037] According to another aspect of the present application, there is provided a computer readable storage medium storing computer instructions for enabling a processor to implement the load test method according to any one of the embodiments of the present application when executed by the processor.

[0038] The technical solution of the embodiments of the present application first acquires 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 obtained by measurement using a phase voltmeter; 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 determined 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, according to the analysis result, an analysis report is generated. By using the above method, on the one hand, it can adapt to the complex and changeable application scenarios in the load test, and at the same time, it can adapt to different voltage levels; on the other hand, by comparing real-time data, visualizing charts and intelligently analyzing results, the digitization and intelligentization of the test are realized, the workload and labor cost of the load test are effectively reduced, the time consumption of the load test is shortened to the minute level, and the efficiency of the load test is fundamentally improved; on the other hand, the intelligent analysis software for load test is used instead of manual operation, which also ensures the safety of personnel to a certain extent, effectively reduces the risk of high-voltage space operation, forms good protection for high-voltage environment operation in the system inspection process, reduces human errors, and ensures the accuracy and stability of the test results.

[0039] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to make the technical solutions in the embodiments of the present application clearer, the accompanying drawings needed in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and all other drawings obtained by those skilled in the art without any creative effort should be within the protection scope of the present application.

[0041] Figure 1 is a flow chart of a load test method provided by the first embodiment of the present application;

[0042] Figure 2 is a flow chart of a load test method provided by the second embodiment of the present application;

[0043] Figure 3 is a flow chart of a load test method provided by the third embodiment of the present application;

[0044] Figure 4 is a structural schematic diagram of a load test device provided by the fourth embodiment of the present application;

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

[0046] In order to make the technical solutions in the embodiments of the present application clearer, the accompanying drawings needed in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and all other drawings obtained by those skilled in the art without any creative effort should be within the protection scope of the present application.

[0047] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-mentioned accompanying drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily have to include only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to the process, method, product or device.

[0048] As described in the background section, there are many defects in the existing load test method, which will be analyzed as follows:

[0049] (1) Low efficiency: Traditional load testing requires the use of instruments such as phase voltammeters to transfer and measure at multiple screen locations one by one. Before recording, the form needs to be manually edited, the recording process is relatively slow, takes a long time and requires a large number of people, so it is inefficient.

[0050] (2) Prone to errors: After the traditional load test data is generated, it is necessary for the relay protection personnel to make manual judgments. However, after a long period of operation overnight, the operators are relatively tired, and their attention and energy are reduced. Moreover, they are limited by the professional and technical knowledge of the reviewers, which can easily lead to errors in the review results. For example, after the protection of a 500kV main transformer was modified, the acceptance personnel did not understand the principle of phase differential protection and ignored the risk of polarity reversal. They did not check the correctness of each current phase when analyzing the load test data, which caused an unplanned third-level power safety incident.

[0051] (3) High cost: Manual review requires multiple layers of review by on-site construction personnel, acceptance personnel, team leaders and specialists, which requires a lot of human resources and time costs, increasing the company's operating costs. In addition, human factors may cause the review results to be delayed, resulting in missing the right time to discover hidden dangers and causing unnecessary trouble and losses to the power grid.

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

[0053] To address the aforementioned problems, embodiments of the present invention provide a method for load testing. Specifically, in one embodiment, Figure 1 This is a flowchart of a load testing method provided in Embodiment 1 of the present invention. This embodiment is applicable to the situation of power grid load testing. The method can be executed by a load testing device, which can be implemented in hardware and / or software, and can be configured in a load testing instrument. Figure 1 As shown, the method includes:

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

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

[0056] S120, according to the actual secondary current amplitude and phase of the current transformer in the bus protection device, the transformer protection device and the line protection device, determining whether the current transformer ratio and polarity in the bus protection device, the transformer protection device and the line protection device are correct, and obtaining an analysis result.

[0057] The step is essentially based on the power flow network of the power system to determine the wiring problem of the current transformer by actually detecting the current. Specifically, as known to those skilled in the art, the current transformer, as a current detection device for detecting the current of the bus, the transformer and the line, has a fixed ratio relationship between the primary side and the secondary side of the winding. In addition, the currents between different positions in the bus, the transformer and the line also have known correlation relationships. Based on these known correlation relationships, the actual secondary current detected by the current transformer can be used to calculate whether these ratio relationships or correlation relationships are correct, thereby inversely deducing whether the current transformer has a ratio and polarity error and whether it is correctly wired according to the standard ratio and polarity relationship.

[0058] S130, generating an analysis report according to the analysis result.

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

[0060] The embodiment one of the application provides a load test method, which comprises the following steps: first, acquiring actual secondary currents of current transformers in bus protection devices, transformer protection devices and line protection devices; the actual secondary currents are measured by using a phase voltmeter; then, judging whether there is an error in the transformation ratio and polarity of the current transformers in the bus protection devices, the transformer protection devices and the line protection devices according to the amplitudes and phases of the actual secondary currents of the current transformers in the bus protection devices, the transformer protection devices and the line protection devices, and obtaining an analysis result; finally, generating an analysis report according to the analysis result. By using the method, on the one hand, the method can adapt to complex and changeable application scenarios in the load test and can be adapted to different voltage levels; on the other hand, the method realizes the digitization and intelligentization of the test through real-time data comparison, chart visualization and intelligent result analysis, effectively reduces the workload and labor cost of the load test, shortens the time consumption of the load test to the minute level, and fundamentally improves the load test efficiency; in addition, the intelligent analysis software for the load test is used to replace manual operation, which can guarantee the safety of personnel to a certain extent, effectively reduce the risk of high-voltage space operation, form a good protection for high-voltage environment operation in the system inspection process, reduce human errors, and ensure the accuracy and stability of the test results. The embodiment of the application can improve the efficiency and accuracy of the load test, the data analysis is more accurate, the test results are more intuitive, the safety and stability of the power system are improved, the complex and changeable main network transformer test requirements are met, the same type of equipment test can be applied, the application range is wide, and strong support is provided for the rapid development of the power system.

[0061] On the basis of the above-mentioned embodiment, a variant embodiment of the above-mentioned embodiment is proposed, and it should be noted that, in order to make the description brief, only the differences between the variant embodiment and the above-mentioned embodiment are described in the variant embodiment.

[0062] In one embodiment, after the step S110 of acquiring the actual secondary currents of the current transformers in the bus protection devices, the transformer protection devices and the line protection devices, the following step can be added before the step S130 of generating the analysis report according to the analysis result:

[0063] S121, drawing a hexagon vector diagram according to the actual secondary currents of the current transformers in the bus protection devices, the transformer protection devices and the line protection devices.

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

[0065] Based on this, the step S130 of the above embodiment, according to the analysis result, generates an analysis report, which can specifically include: S131, according to the analysis result and the hexagon vector diagram, generating an analysis report.

[0066] In this embodiment, the on-load test analysis software automatically draws the hexagon vector diagram, which not only provides the analysis result of the current transformer ratio and polarity, but also provides the user with a visual hexagon vector diagram, which facilitates the maintenance personnel to simultaneously perform manual analysis and judgment, and further guarantees the reliability and accuracy of the on-load test.

[0067] Figure 2 A flowchart of an on-load test method provided in the second embodiment of the present application, which is a refinement based on the above embodiment. Specifically, the step S120 of the above embodiment can specifically include:

[0068] Obtaining the primary current and the ratio of the current transformer in the bus protection device, the transformer protection device and the line protection device;

[0069] According to the primary current and the ratio of the current transformer 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 transformer in the bus protection device, the transformer protection device and the line protection device are calculated by power angle relationship method and power flow calculation;

[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 the preset threshold, it is judged whether the current transformer has ratio error;

[0071] 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 the preset threshold, it is judged whether the current transformer has polarity error.

[0072] The details of this embodiment are not described in detail, please refer to the first embodiment.

[0073] As Figure 2As shown, the load test method provided by the second embodiment of the present application comprises the following steps:

[0074] In S210, the actual secondary currents of the current transformers in the bus protection device, the transformer protection device and the line protection device are acquired.

[0075] In S220, a hexagon vector diagram is drawn according to the actual secondary currents of the current transformers in the bus protection device, the transformer protection device and the line protection device.

[0076] In S221, the primary currents and the transformation ratios of the current transformers in the bus protection device, the transformer protection device and the line protection device are acquired.

[0077] First of all, it needs to be explained that the load test software provided by the present application needs to acquire basic parameters, such as the power equipment condition, the key parameters of the main transformer differential protection, the intermediate data and the setting standard, before analyzing and judging the transformation ratio and the problem of the current transformer. This step is the process of inputting the primary currents and the transformation ratios of the current transformers into the load test software.

[0078] In S222, the amplitude and the phase of the standard secondary currents 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 and the power flow according to the primary currents and the transformation ratios of the current transformers in the bus protection device, the transformer protection device and the line protection device.

[0079] For the bus protection device, the transformer protection device and the line protection device, the transformation ratio and the polarity problem of the current transformers therein can be calculated by the power angle relationship method and the power flow to obtain the rated secondary current value, i.e., the standard secondary current. Specifically, the power angle relationship formula is: According to the power angle relationship formula, the amplitude and the phase of the A-phase CT secondary current calculated by the power flow data are taken as the reference basis.

[0080] In S223, whether the current transformer has a transformation ratio error is judged according to whether the difference between the amplitude of the actual secondary current and the amplitude of the standard secondary current of the current transformer exceeds a preset threshold value.

[0081] In S224, whether the current transformer has a polarity error is judged according to whether the difference between the phase of the actual secondary current and the phase of the standard secondary current of the current transformer exceeds a preset threshold value.

[0082] Under the general correct connection condition, the three-phase current amplitudes are basically the same, and the current phase sequences are A phase leading B phase, B phase leading C phase, that is, the phase sequence difference is 120° standard. Based on this, the measured three-phase current amplitudes and current phase sequences can be checked one by one. Specifically, the error of the actual measurement value and the reference value can be judged, and if the deviation is greater than 10%, it is considered that there may be CT polarity or transformation ratio error. Among them, when there is a significant difference between the actual value and the reference value of the secondary current, it can be indicated that the CT joint connection is wrong, which causes the polarity error; when there is a significant difference in phase, it can be indicated that the CT tap connection is wrong, which causes the transformation ratio error.

[0083] S230, generating an analysis report according to the analysis result and the hexagon vector diagram.

[0084] The load test method provided by the second embodiment of the present application compares the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device with the standard secondary current calculated by the power angle method, and specifically judges whether the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device are correct according to the amplitude and phase of the actual secondary current of the current transformer. By using the method, the transformation ratio and polarity of the current transformer at each position can be accurately judged, and it can be determined whether the joint connection or the tap connection is the problem, so that more accurate, efficient and direct analysis results are provided.

[0085] Figure 3 The flowchart of the load test method provided by the third embodiment of the present application is also a refinement based on the above-mentioned embodiment. Specifically, the above-mentioned embodiment S120 can specifically include:

[0086] According to the actual secondary current of the current transformer on both sides of the line power supply end and the output end, the difference current on both sides of the line is calculated;

[0087] According to whether the difference current on both sides of the line exceeds the preset threshold, it is judged whether the current transformer at the line position has polarity or transformation ratio error.

[0088] Optionally, the above-mentioned embodiment S120 can also specifically include:

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

[0090] According to whether the difference currents of various types are within the standard range, it is determined whether the current transformers on each side of the main transformer have polarity or transformation ratio error.

[0091] Further, according to the installation type of the current transformer in the transformer protection device, according to the longitudinal differential, the split-phase differential, the split-side differential, the zero sequence differential and the bushing differential flow principle, before calculating the differential flow of each type, 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 wiring mode of the current transformer on each side, the current on the high voltage side of the main transformer is phase-corrected and balanced coefficient compensated.

[0093] Alternatively, the above embodiment S120 can 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 value, it is judged whether the polarity or transformation ratio of the corresponding current transformer is wrong.

[0096] The details of the present embodiment not yet described can refer to embodiments one and two.

[0097] As shown in Figure 3 The load test method provided by the embodiment three of the present application includes the following steps:

[0098] S310, the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device is obtained; the actual secondary current is obtained by measuring with a phase voltmeter.

[0099] S320, according to the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, a hexagonal vector diagram is drawn.

[0100] S3211, according to the actual secondary current of the current transformer on both sides of the line power supply end and the output end, the differential flow on both sides of the line is calculated.

[0101] S3212, according to whether the differential flow on both sides of the line exceeds the preset threshold, it is judged whether the polarity or transformation ratio of the current transformer at the line is wrong.

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

[0103] S3221, according to the rated voltage, rated capacity and rated current of the main transformer, and the transformation ratio and wiring mode of each side current transformer, the current of the high voltage side of the main transformer is phase-corrected and balanced coefficient compensated.

[0104] S3222, according to the installation type of the current transformer in the transformer protection device, each type of differential current is calculated according to the longitudinal differential, phase differential, side differential, zero sequence differential and bushing differential current principle.

[0105] S3223, according to whether each type of differential current is within the standard range, it is determined whether the polarity or transformation ratio of each side current transformer of the main transformer is wrong.

[0106] The above steps S3221-S3223 are essentially the process of analyzing and judging the correctness of the secondary circuit of the main transformer by differential current analysis method. Specifically, in this process, different differential current calculation methods need to be selected 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 switch CT, longitudinal differential, phase differential, side differential, zero sequence differential differential current calculation can be performed; for bushing CT, bushing differential current calculation can be further increased. It can be understood that longitudinal differential, phase differential, side differential, zero sequence differential and bushing differential current are also the basic process of corresponding differential protection, and this step is also essentially a process of judging the abnormal connection of the current transformer according to the differential protection principle. Among them, the protection scheme of longitudinal differential is the traditional longitudinal differential protection composed of high, medium and low side switch CT. The protection scheme of phase differential is the phase differential protection composed of high and medium voltage side switch CT and low voltage side delta winding (bushing) CT. The protection scheme of side differential is the 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 the differential protection composed of high, medium and low side zero sequence currents. The protection scheme of bushing differential current is the differential protection composed of high, medium and low bushing CT.

[0107] Those skilled in the art can know that due to the different transformation ratio and wiring of the CT of each side of the main transformer, phase difference adjustment and balance coefficient method are needed to compensate for the phase shift and transformation ratio. The specific way of phase correction and balance coefficient compensation is introduced as follows:

[0108] ①Taking Y->△ secondary current phase difference compensation as an example, for △ as 11 o'clock wiring, the phase difference of the secondary current loop of each side CT should be calculated according to the difference amplitude of each phase current, and the balance of the differential current should be adjusted uniformly by Y->△ change. The correction method is as follows:

[0109]

[0110] wherein, is the Y-side secondary current of the CT, is the Y-side corrected current of each phase.

[0111] ② Calculation of the balance coefficient. The balance coefficient of the main transformer at the medium and low voltage sides is calculated based on the high voltage side:

[0112]

[0113] wherein, H, M, and L are the high, medium, and low voltage sides, respectively, S e is the three-phase rated capacity of the high and medium voltage sides; U 1e is the primary rated voltage; I 1e is the primary rated current; I 2e is the secondary rated current; and n LH is the CT transformation ratio. The amplitude-compensated current of each phase is obtained by multiplying the current of each phase at the medium and low voltage sides by the corresponding balance coefficient.

[0114] S3231, the busbar large differential circuit current, the Ibus small differential circuit current, and the IIbus small differential circuit current are calculated according to the actual secondary currents of the current transformers of each branch at the busbar.

[0115] S3232, whether the corresponding current transformer has polarity or transformation ratio error is determined according to whether the busbar large differential circuit current, the Ibus small differential circuit current, and the IIbus small differential circuit current exceed the corresponding standard values.

[0116] The above steps S3231 and S3232 are essentially a process of analyzing and determining the correctness of the secondary circuit of the busbar through the differential current analysis method. Specifically, the busbar differential current can include the busbar large differential circuit and the small differential circuit of each section of the busbar. The busbar differential is composed of the split-phase differential element, the busbar large differential refers to the current sum and absolute value of all branch currents except the bus tie CT, and the small differential of each section of the busbar refers to the current sum and absolute value of all branch currents (including the bus tie and the section) on the section of the busbar. The busbar large differential is used to determine the fault within and outside the busbar area, and the small differential is used for fault bus selection. When any phase of the calculated value of all differential currents in the busbar 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, and the differential current calculation formula is as follows:

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

[0118] Ibus small differential current:

[0119] IIbus small differential current:

[0120] wherein, I1, I2, …, I nis the primary current value of each branch; I ML is the primary current value of the bus tie, and the direction is adjusted according to each section of the bus; S 11 , S 12 ,..., S 1n is the position of the I bus disconnecting switch of each branch (0 indicates that the switch is open, and 1 indicates that the switch is closed); S 21 , S 22 ,..., S 2n is the position of the II bus disconnecting switch of each branch (0 indicates that the switch is open, and 1 indicates that the switch is closed).

[0121] S330, according to the analysis result and the hexagon vector diagram, an analysis report is generated.

[0122] The load test method provided in the embodiment three adopts the differential current analysis method to judge the correctness of the secondary circuit, and specifically realizes the process of judging whether the current transformer ratio and polarity in the bus protection device, the transformer protection device and the line protection device exist errors according to the actual secondary current amplitude and phase of the current transformer in the bus protection device, the transformer protection device and the line protection device. By using the method, when the line, the main transformer and the bus equipment perform differential current calculation according to the differential current analysis method, if any phase differential current is greater than 0.04A, it can be preliminarily judged that the CT loop polarity or ratio exists a problem. The judgment method has simple principle and fast response, can be complementary to the power angle relationship method in the embodiment two, avoids the case that the load is small and the differential current change is not obvious, and ensures that the complex and changeable application scene in the load test can be adapted.

[0123] Figure 4 is a structural schematic diagram of a load test device provided in the embodiment four of the application. As shown in the figure, Figure 4 the device comprises:

[0124] The acquisition module 100 is used to acquire 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 obtained by measuring with a phase voltmeter;

[0125] The judgment module 200 is used to judge whether the current transformer ratio and polarity in the bus protection device, the transformer protection device and the line protection device exist errors according to the actual secondary current amplitude and phase 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 result.

[0127] In an embodiment, the judgment module 200 can comprise:

[0128] a data acquisition unit configured to acquire the primary current and the transformation ratio of the current transformer in the bus protection device, the transformer protection device, and the line protection device;

[0129] a power flow calculation unit configured to calculate the amplitude and the phase of the standard secondary current of the current transformer in the bus protection device, the transformer protection device, and the line protection device by the power angle relationship method according to the primary current and the transformation ratio of the current transformer in the bus protection device, the transformer protection device, and the line protection device;

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

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

[0132] In an embodiment, the judgment module 200 can include:

[0133] a line differential current calculation unit configured 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] a line CT judgment unit configured to judge whether the current transformer at the line has a polarity or transformation ratio error according to whether the differential current on both sides of the line exceeds a preset threshold value.

[0135] In an embodiment, the judgment module 200 can include:

[0136] a transformer differential current calculation unit configured to calculate various types of differential currents according to the installation type of the current transformer in the transformer protection device according to the longitudinal differential, the split-phase differential, the split-side differential, the zero-sequence differential, and the bushing differential current principle;

[0137] a transformer CT judgment unit configured to determine whether the current transformer on each side of the transformer has a polarity or transformation ratio error according to whether the various types of differential currents are within a standard range.

[0138] Further, the judgment module 200 can further include:

[0139] The correction and compensation unit is used for correcting the phase and compensating the balance coefficient of 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 mode of the current transformer on each side before calculating the differential currents of various types according to the installation type of the current transformer in the transformer protection device, i.e., longitudinal differential, phase differential, side differential, zero sequence differential and bushing differential.

[0140] In an embodiment, the judging module 200 can include:

[0141] The bus differential current calculation unit is used for calculating the bus large differential loop current, the I bus small differential loop current and the II bus small differential loop current respectively according to the actual secondary currents of the current transformers of each branch at the bus.

[0142] The bus CT judging unit is used for judging whether the corresponding current transformer has polarity or transformation 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 an embodiment, the device can further include:

[0144] The drawing unit is used for drawing a hexagon 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 before generating the analysis report according to the analysis result after obtaining the actual secondary currents of the current transformers in the bus protection device, the transformer protection device and the line protection device.

[0145] Based on this, the report generation module 300 is further used for generating the analysis report according to the analysis result and the hexagon vector diagram.

[0146] The load testing device provided by the embodiment of the present application can execute the load testing method provided by any of the embodiments of the present application, and has the corresponding function modules and beneficial effects of the execution method.

[0147] In an embodiment, Figure 5 is a structural block diagram of an electronic device provided by an embodiment of the present application, such as Figure 5As shown, a structural diagram of an electronic device 10 that can be used to implement embodiments of the present application is shown. The electronic device is intended to represent various forms of digital computers, such as laptops, desktops, tablets, personal digital assistants, servers, blade servers, mainframes, and other appropriate computers. The electronic device can also represent various forms of mobile devices, such as personal digital assistants, cellular telephones, smartphones, wearable devices (e.g., headsets, glasses, watches, etc.), and other similar computing devices. The components shown here, their connections and relationships, and their functions, are meant to be examples only, and are not meant to limit implementations of the present application described and / or claimed in this document.

[0148] As shown, Figure 5 The electronic device 10 includes at least one processor 11, and a memory, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc., connected to the at least one processor 11, where the memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes according to the computer programs stored in the read-only memory (ROM) 12 or loaded from the storage unit 18 into 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] Various 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 magnetic 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 can be various general and / or special purpose 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 special-purpose 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 performs various methods and processes described above, such as the load testing method.

[0151] In some embodiments, the load testing method can be implemented as a computer program tangibly embodied in a computer readable storage medium, e.g., storage unit 18. In some embodiments, parts or all of the computer program can be loaded and / or installed onto electronic device 10 via, e.g., ROM 12 and / or communication unit 19. When the computer program is loaded onto RAM 13 and executed by processor 11, one or more steps of the load testing method described above can be performed. Alternatively, in other embodiments, processor 11 can be configured to perform the load testing method by other means, e.g., with the aid of firmware.

[0152] Various implementations of the systems and techniques described above can be realized in digital electronic circuitry, integrated circuitry, specially designed application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs that are executable and / or interpretable on a programmable system including at least one programmable processor, which can be special or general purpose, coupled to receive data and instructions from, and to transmit data and instructions to, a storage system, at least one input device, and at least one output device.

[0153] Computer programs used to implement the methods of the application can be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the computer program, when executed by the processor of the computer or other programmable data processing apparatus, enables the systems and methods as claimed in the claims to be implemented. The computer program can be executed entirely on a machine, partially on a machine and partially on a remote machine or entirely on a remote machine or server.

[0154] In the context of the present application, a computer-readable storage medium can be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. A computer-readable storage medium can include, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium can be a machine-readable signal medium. More specific examples of a machine-readable storage medium will include one or more lines of a program of instructions in a transitory signal, a portable computer diskette, 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 disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0155] To provide for interaction with a user, the systems and techniques described here can 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 a trackball) by which the user can provide input to the electronic device. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form, including acoustic, speech, or tactile input.

[0156] The systems and techniques described here can be implemented in a computing system that includes a back end component (e.g., as a data server), or that includes a middleware component (e.g., an application server), or that includes a front end component (e.g., a user computer having a graphical user interface or a Web browser through which a user can interact with an implementation of the systems and techniques described here), or any combination of such back end, middleware, or front end components. The components of the system can 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] The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. The server can 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 large management difficulty and weak business scalability in traditional physical host and VPS service.

[0158] It should be understood that the various forms of flow shown above can be reordered, added to, or have steps deleted. For example, the steps described in the present application can be performed in parallel, in series, or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, and this is not limited herein.

[0159] The above detailed description does not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A load testing method, characterized by, The method comprises the following steps: 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 obtained by using a phase voltmeter; determining whether the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device are incorrect 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 obtaining an analysis result; generating an analysis report according to the analysis result; determining whether the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device are incorrect 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 obtaining an analysis result, comprising: obtaining the primary current and transformation ratio of the current transformer in the bus protection device, the transformer protection device and the line protection device; calculating the amplitude and phase of the standard secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device by power angle relationship method according to the primary current and transformation ratio of the current transformer in the bus protection device, the transformer protection device and the line protection device; determining whether the transformation ratio of the current transformer is incorrect according to whether the difference between the amplitude of the actual secondary current and the amplitude of the standard secondary current exceeds a preset threshold value; determining whether the polarity of the current transformer is incorrect according to whether the difference between the phase of the actual secondary current and the phase of the standard secondary current exceeds a preset threshold value.

2. The load test method according to claim 1, wherein determining whether the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device are incorrect 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 obtaining an analysis result, comprising: calculating the line side difference current according to the actual secondary current of the current transformer on both sides of the line power supply end and the output end; determining whether the current transformer at the line has polarity or transformation ratio error according to whether the line side difference current exceeds a preset threshold value.

3. The load testing method of claim 1, wherein, determining whether the transformation ratio and polarity of the current transformer in the bus protection device, the transformer protection device and the line protection device are incorrect 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 obtaining an analysis result, comprising: calculating various types of difference currents according to the installation type of the current transformer in the transformer protection device according to the principles of longitudinal differential, split-phase differential, split-side differential, zero sequence differential and bushing differential; determining whether the current transformer on each side of the main transformer has polarity or transformation ratio error according to whether each type of difference current is within a standard range.

4. The load testing method of claim 3, wherein, before calculating various types of difference currents according to the installation type of the current transformer in the transformer protection device according to the principles of longitudinal differential, split-phase differential, split-side differential, zero sequence differential and bushing differential, further comprising: According to the rated voltage, rated capacity and rated current of the main transformer, and the transformation ratio and connection mode of each side current transformer, the current on the high voltage side of the main transformer is phase-corrected and balanced coefficient compensated.

5. The load testing method of claim 1, wherein, 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, including: According to the actual secondary current of the current transformer of each branch at the bus, the bus large difference loop current, the I bus small difference loop current and the II bus small difference loop current are calculated respectively; According to whether the bus large difference loop current, the I bus small difference loop current and the II bus small difference loop current exceed the corresponding standard value, it is judged whether there is a polarity or transformation ratio error in the corresponding current transformer.

6. The load test method according to claim 1, wherein After obtaining the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, before generating an analysis report according to the analysis result, it further includes: According to the actual secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device, a hexagonal vector diagram is drawn; According to the analysis result, an analysis report is generated, including: According to the analysis result and the hexagonal vector diagram, an analysis report is generated.

7. A load testing device, characterized by It includes: The acquisition module is used for acquiring 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 obtained by measuring with a phase voltmeter; The judgment module is used for judging 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, and obtaining an analysis result; The report generation module is used for generating an analysis report according to the analysis result; The judgment module includes: The data acquisition unit is used for acquiring the primary current and transformation ratio of the current transformer in the bus protection device, the transformer protection device and the line protection device; The power flow calculation unit is used for calculating the amplitude and phase of the standard secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device through the power angle relationship method according to the primary current and transformation ratio of the current transformer in the bus protection device, the transformer protection device and the line protection device; The transformation ratio judgment unit is used for judging whether there is a transformation ratio error in the current transformer according to whether the difference between the amplitude of the actual secondary current and the amplitude of the standard secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device exceeds a preset threshold value; The polarity judgment unit is used for judging whether there is a polarity error in the current transformer according to whether the difference between the phase of the actual secondary current and the phase of the standard secondary current of the current transformer in the bus protection device, the transformer protection device and the line protection device exceeds a preset threshold value.

8. An electronic device, comprising: The electronic device includes: At least one processor; and The memory is connected in communication with the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, the computer program being executed by the at least one processor to enable the at least one processor to perform the load testing method of any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer readable storage medium stores computer instructions for causing a processor to implement the load testing method of any one of claims 1-6 when executed.

Images