Resistance measuring device applied to any parallel branch of primary equipment

Abstract

The invention relates to a resistance measuring device applied to any parallel branch of primary equipment, which comprises a voltage measuring module, a current measuring module, a current source module and a processor, and the voltage measuring module, the current measuring module and the current source module are all connected with the processor. The current source module, the voltage measurement module and the current measurement module are all arranged on a measured circuit and used for obtaining circuit parameters and sending the circuit parameters to the processor, and the processor is used for determining resistance parameters of the measured circuit according to the circuit parameters. The voltage measurement module, the current measurement module and the current source module are arranged to accurately measure the circuit parameters of the measured circuit, so that the processor can perform operation according to the circuit parameters to obtain the resistance of the measured branch. The setting positions of the modules are adjusted according to the detected circuit, so that the processor can detect the resistance of the detected circuit according to different mode operation, the resistance of a specified branch in the multi-contact-surface branch can be measured, and the applicability of the resistance measuring device is improved.

Description

Technical Field

[0001] The present application relates to the technical field of electrical power grids, and in particular to a resistance measuring device applied to any parallel branch of a primary device. Background Art

[0002] In recent years, the methods for measuring the loop resistance of circuit breakers, disconnectors and other equipment in substations have become relatively mature and abundant. However, the contact resistance measurement of the contact surface between some equipment that is difficult to disassemble or temporarily non-detachable is not so convenient and accurate.

[0003] For example, the 500kV GW6A-550 scissor-type knife switch has four parallel contact surfaces. Since it is a non-detachable parallel structure, only the resistance of the entire contact can be measured, and it is extremely difficult to measure the resistance of the branches where the four contact surfaces are located, and it is impossible to obtain the individual resistance of each contact surface. When one of the four contact surfaces fails, has poor contact and heats up, it is impossible to measure the contact surface resistance individually, and it is impossible to accurately locate the contact surface where the failure occurs, which poses certain operational safety risks.

[0004] Current resistance measuring instruments are usually only equipped with a current source clamp, which can only measure the resistance of a parallel loop, but cannot accurately detect the resistance of a specified branch in a multi-contact surface branch, resulting in a problem of low applicability. Summary of the invention

[0005] Based on this, it is necessary to provide a resistance measuring device for any parallel branch of a primary device that can improve applicability in order to address the above technical problems.

[0006] The present application provides a resistance measurement device applied to any parallel branch of a primary device, comprising a voltage measurement module, a current measurement module, a current source module and a processor, wherein the voltage measurement module, the current measurement module and the current source module are all connected to the processor;

[0007] The current source module, the voltage measurement module and the current measurement module are all arranged in the circuit under test, and are used to obtain circuit parameters and send them to the processor, and the processor is used to determine the resistance parameters of the circuit under test according to the circuit parameters.

[0008] In one embodiment, the current source module includes a first current source clamp and a second current source clamp, the first current source clamp and the second current source clamp are both connected to the processor, the first current source clamp is arranged at the first end of the circuit under test, and the second current source clamp is arranged at the second end of the circuit under test.

[0009] In one embodiment, the current measurement module includes a plurality of current clamps, and each of the current clamps is connected to the processor.

[0010] In one embodiment, the circuit under test includes a main loop and more than two accessible branches, each current clamp is respectively arranged at each accessible branch, the current source module is arranged at the main loop and any one of the accessible branches, and the voltage measurement module is arranged at any one of the accessible branches.

[0011] In one of the embodiments, the number of the current clamps matches the number of the accessible branches.

[0012] In one of the embodiments, the number of the current clamps is one less than the number of the accessible branches.

[0013] In one embodiment, the circuit under test also includes an inaccessible branch, each of the current clamps is respectively arranged on a accessible branch connected to the inaccessible branch, the current source module is arranged on the circuit under test, and the voltage measurement module is arranged on the inaccessible branch.

[0014] In one embodiment, the current measurement module is a Hall current loop element.

[0015] In one of the embodiments, the device further comprises an interaction module, and the interaction module is connected to the processor.

[0016] In one of the embodiments, the device further includes a communication module, and the processor is connected to the voltage measurement module, the current measurement module and the current source module through the communication module.

[0017] The above-mentioned resistance measuring device applied to any parallel branch of a primary device includes a voltage measuring module, a current measuring module, a current source module and a processor, and the voltage measuring module, the current measuring module and the current source module are all connected to the processor. The current source module, the voltage measuring module and the current measuring module are all arranged in the circuit under test, and are used to obtain circuit parameters and send them to the processor, and the processor is used to determine the resistance parameters of the circuit under test according to the circuit parameters. By setting the voltage measuring module, the current measuring module and the current source module, the circuit parameters of the circuit under test are accurately measured, so that the processor can perform calculations according to the circuit parameters to obtain the resistance of the branch under test. The setting position of each module is adjusted according to the circuit under test, so that the processor can detect the resistance of the circuit under test according to different mode calculations, and can realize the measurement of the resistance of the specified branch in the multi-contact surface branch, thereby improving the applicability of the resistance measuring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] FIG1 is a schematic structural diagram of a resistance measuring device applied to any parallel branch of a primary device in one embodiment;

[0020] FIG2 is a schematic structural diagram of a resistance measuring device applied to any parallel branch of a primary device in another embodiment;

[0021] FIG3 is a wiring diagram of a current source module in one embodiment;

[0022] FIG4 is a schematic diagram of an interface of a display screen in one embodiment;

[0023] FIG5 is a schematic diagram of a partial circuit equivalent of a circuit under test in one embodiment;

[0024] FIG6 is a schematic diagram of a partial circuit equivalent of a circuit under test in another embodiment;

[0025] FIG7 is a schematic diagram of the structure and wiring of a scissor-type knife switch in one embodiment;

[0026] FIG8 is a schematic diagram of the resistance equivalent of a scissor-type knife switch in one embodiment;

[0027] FIG9 is a schematic diagram of a circuit equivalent of a contact surface to be tested in one embodiment;

[0028] FIG. 10 is a schematic diagram of the structure and wiring of a scissor-type knife switch in another embodiment. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. The embodiments of the present application are given in the accompanying drawings, but the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0030] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0031] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0032] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0033] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0035] The resistance measuring device provided in each embodiment of the present application can be applied to any parallel branch of a primary device, and can measure the contact surface resistance of multiple branches, solving the problem that the traditional loop resistance tester cannot measure the contact resistance of multiple branches. Specifically, the resistance measuring device for any parallel branch of a primary device provided in the present application can not only be applied to the common loop resistance measurement environment, but also can measure the branch resistance, especially when there are multiple contact surfaces in the loop, the resistance of the specified contact surface can be measured.

[0036] In one embodiment, as shown in FIG1 , a resistance measuring device applied to any parallel branch of a primary device is provided, including a voltage measuring module 102, a current measuring module 104, a current source module 106 and a processor 108, wherein the voltage measuring module 102, the current measuring module 104 and the current source module 106 are all connected to the processor 108. Among them, the current source module 106 is the basis for resistance measurement, and the current source can generate a stable current, and the output current can be constant. The voltage measuring module 102 and the current measuring module 104 can detect voltage parameters and current parameters respectively, and the voltage measuring module 102 and the current measuring module 104 are usually used in conjunction with the current source module 106 to facilitate the processor 108 to calculate the resistance.

[0037] The current source module 106, the voltage measurement module 102 and the current measurement module 104 are all arranged in the circuit under test, and are used to obtain the circuit parameters and send them to the processor 108, and the processor 108 is used to determine the resistance parameters of the circuit under test according to the circuit parameters. Specifically, the current source module 106, the voltage measurement module 102 and the current measurement module 104 are combined to detect the circuit under test to obtain the circuit parameters of the circuit under test, wherein the circuit parameters include current parameters and voltage parameters, the current source module 106 is used to input a constant current to the circuit under test, the current measurement module 104 is used to obtain the current parameters of the circuit under test, and the voltage measurement module 102 is used to obtain the voltage parameters of the circuit under test.

[0038] Specifically, according to the different settings of the current measurement module 104 in the circuit under test, the meaning represented by the obtained current parameter is also different. For example, when the current measurement module 104 is set in a branch of the circuit under test, the current parameter obtained at this time represents the current of the branch; when the current measurement module 104 is set in the loop of the circuit under test, the current parameter obtained at this time represents the current of the loop of the circuit under test. Similarly, the voltage measurement module 102 is set at different locations, and the meaning represented by the obtained voltage parameter is also different. Optionally, the voltage measurement module 102 is set at both ends of the location where the resistor to be measured is located, and the voltage on the resistor to be measured can be directly obtained.

[0039] After the current measurement module 104 and the voltage measurement module 102 obtain the circuit parameters, they send the circuit parameters to the connected processor 108. The processor 108 has computing power, can perform calculations based on the circuit parameters, and can use different calculation logics in combination with the selected measurement mode to determine the resistance parameters of the measured circuit. Among them, the user can set the current measurement module 104, the voltage measurement module 102 and the current source module 106 to different positions according to actual measurement requirements, and select the corresponding measurement mode on the processor 108. The processor 108 calculates the resistance parameters of the measured circuit based on the selected measurement mode and the circuit data.

[0040] In this embodiment, the resistance measuring device applied to any parallel branch of a primary device includes a voltage measuring module 102, a current measuring module 104, a current source module 106 and a processor 108, wherein the voltage measuring module 102, the current measuring module 104 and the current source module 106 are all connected to the processor 108. The current source module 106, the voltage measuring module 102 and the current measuring module 104 are all arranged in the measured circuit, and are used to obtain the circuit parameters and send them to the processor 108, and the processor 108 is used to determine the resistance parameters of the measured circuit according to the circuit parameters. The circuit parameters of the measured circuit are accurately measured by setting the voltage measuring module 102, the current measuring module 104 and the current source module 106, so that the processor 108 performs calculations according to the circuit parameters to obtain the resistance of the measured branch. The setting position of each module is adjusted according to the measured circuit, and the processor 108 can detect the resistance of the measured circuit according to different mode calculations, and can realize the measurement of the resistance of the specified branch in the multi-contact surface branch, thereby improving the applicability of the resistance measuring device.

[0041] In one embodiment, as shown in FIG. 2 , the resistance measurement device applied to any parallel branch of a primary device further includes an interaction module 110 , and the interaction module 110 is connected to the processor 108 .

[0042] The interactive module 110 is used for the user to interact with the processor 108, and may include a display module and an input module. The display module may include devices such as a display screen and a digital tube, and the input module may include devices such as buttons, switches, keyboards, and mice. Optionally, the interactive module 110 may be a touch screen that can simultaneously complete the user's data input and the processor 108's data expression.

[0043] The processor 108 is connected to the interactive module 110. When the circuit parameters are acquired, the processor 108 can display the circuit parameters to the user through the interactive module 110, and after the resistance value is calculated, the resistance value can be displayed to the user through the interactive module 110. The user can also switch and select the measurement mode of the processor 108 through the interactive module 110, so that the measurement mode matches the setting position of each module on the measured circuit, so that the calculation result of the processor 108 is accurate.

[0044] In one embodiment, the current source module 106 includes a first current source clamp and a second current source clamp, both of which are connected to the processor 108, the first current source clamp is arranged at the first end of the circuit under test, and the second current source clamp is arranged at the second end of the circuit under test.

[0045] The current source module 106 needs to be set in the circuit under test to output a stable current to the circuit under test. Specifically, the current source module 106 includes a first current source clamp and a second current source clamp, and the two clamps can clamp the circuit of the circuit under test so as to be fixedly set in the circuit under test. The first current source clamp and the second current source clamp can be set at both ends of the circuit under test, and transmit current source data to the processor 108 respectively. The processor 108 calculates the difference between the current source data at both ends to obtain the resistance value of the circuit under test.

[0046] Exemplarily, when the resistance measuring device only includes the current source module 106 and the processor 108, and the current source module 106 includes the first current source clamp and the second current source clamp, the resistance measuring device is used to detect the resistance of the loop, or detect the contact surface resistance of the loop including only a single contact surface. In practical applications, the first current source clamp and the second current source clamp are distinguished by shells of different colors, and are connected to the two ends of the circuit under test accordingly. As shown in Figure 3, the special test line is connected to the clamp and the processor 108 using the test line according to the color of the mark, red to red, black to black, the thicker current line in the special test line is connected to the corresponding I+, I- terminal posts and tightened, and the thinner voltage line is connected to the V+, V- terminal posts and tightened. The first current source clamp and the second current source clamp are clamped at the specified position of the circuit under test, and the current source data is obtained and transmitted to the processor 108, and the processor 108 obtains the resistance.

[0047] Further, when the resistance measuring device includes an interactive module 110, the user can obtain the current measurement module and measurement time through the interactive module 110, and can select the measurement mode through a button or by interacting with the touch screen. Under the measurement mode shown in Figure 3, the user can select the conventional loop mode to measure the loop resistance. After selecting the conventional loop mode, the user can start the measurement by pressing the test key, and the current source data of the current source module 106 is first displayed on the display screen, and the prompt "testing" can be prompted at the same time, and then the processor 108 calculates the loop resistance and displays it on the display screen. Further, when the user presses the test key to start the measurement, the display screen can start to display the timing at the same time, and the timing stops until the display screen displays the loop resistance. For example, the measured loop resistance, the current value output by the current source module 106, and the time used to calculate the loop resistance can be displayed on the display screen at the same time. As shown in Figure 4, the measured loop resistance is 496.5 micro-ohms, and the current used for the current source measurement is 202.2A, and this measurement takes 25 seconds.

[0048] Further, after obtaining the measured loop resistance, the display screen can update the displayed data in real time, that is, the detection time increases with the display time, and the measured loop resistance and the current used for current source measurement change in real time. After the test is completed, the reset button can be pressed, the current source module 106 stops the current output, and the display screen is reset.

[0049] In order to more accurately measure the currents of different branches, in one embodiment, the current measurement module 104 includes a plurality of current clamps, each of which is connected to the processor 108 .

[0050] Specifically, the current clamp can be clamped at different positions of the circuit under test to measure the current at each position. When the circuit under test has more branches, more current clamps are needed to measure the current of multiple branches. The current clamp can be set on different branches of the circuit under test. When the current clamp clamps the branch, the current clamp can measure the current parameters of the branch and send the current parameters to the processor 108, so that the processor 108 can calculate the resistance of the circuit under test based on the current parameters.

[0051] Optionally, when the current source module 106 includes a first current source clamp and a second current source clamp, each current clamp of the current measurement module 104 can be combined with the current source module 106 to complete the resistance measurement of the circuit under test. That is, the first current source clamp and the second current source clamp of the current source module 106 are set at both ends of the circuit under test, and the current clamp of the current measurement module 104 is also set at the circuit under test, and the processor 108 obtains the current source data and the current parameters, and calculates and obtains the resistance of the circuit under test.

[0052] Furthermore, in one embodiment, the current measurement module 104 is a Hall current loop element. The current detection principle of the Hall current loop element is: when the original current passes through a long wire, a magnetic field is generated in the annular magnetic core, and the magnitude of the magnetic field is proportional to the current passing through the wire. Then, the magnitude of the original current can be calculated by detecting the magnetic field generated by the magnetic ring. The current measurement module 104 generates current parameters according to the magnitude of the original current and transmits them to the processor 108, and the processor 108 calculates the corresponding resistance according to the current parameters. When the current measurement module 104 includes multiple current clamps, each current clamp is a Hall current loop element, which can independently measure the current in the branch and generate corresponding current parameters.

[0053] The resistance measuring device can be applied to different circuits under test. In one embodiment, the circuit under test includes a loop main circuit and two or more contactable branches, and the resistance measuring device can measure not only the loop main circuit but also the contactable branches. Each current clamp is respectively arranged at each contactable branch, the current source module 106 is arranged at the loop main circuit and any contactable branch, and the voltage measuring module 102 is arranged at any contactable branch.

[0054] Specifically, the loop main circuit of the measured circuit is connected to each contactable branch, and each contactable branch may intersect at one point, and the point is connected to the loop main circuit. In this case, the resistance measuring device can measure the loop main circuit and each contactable branch of the measured circuit. The measurement method of the loop main circuit has been recorded above and will not be repeated here. When measuring each contactable branch, each current clamp is set on each contactable branch, and at most one current clamp is set on a contactable branch. At the same time, one of the first current source clamp and the second current source clamp of the current source module 106 is set on the loop main circuit of the measured circuit, and the other is set on any contactable branch of the measured circuit where the current clamp is set. After completing the setting of the current source module 106 and the current measurement module 104, the voltage measurement module 102 is set on any contactable branch. Optionally, the voltage measurement module 102 can be set on the contactable branch to be measured. In this case, the processor 108 can receive current source data, current parameters of the plurality of branches, and voltage parameters of the accessible branches being measured.

[0055] In one embodiment, the voltage measurement module 102 may include a first voltage clamp and a second voltage clamp. The first voltage clamp and the second voltage clamp are both arranged in the circuit under test, so that the voltage parameter between the first voltage clamp and the second voltage clamp can be measured.

[0056] Since the number of accessible branches and the number of current clamps are not limited, the relationship between the number of accessible branches and the number of current clamps is discussed in various cases below:

[0057] In one embodiment, the number of current clamps matches the number of accessible branches. In this case, the number of current clamps is the same as the number of accessible branches, and each accessible branch is clamped with a current clamp. The processor 108 can obtain the current parameters of all accessible branches, and can also obtain the current source data of a accessible branch and the loop main circuit, as well as the voltage of the designated accessible branch. Then, the processor 108 can first calculate the resistance of the designated accessible branch according to the resistance calculation formula in the circuit, and then calculate the resistance of each accessible branch.

[0058] In another case, the number of current clamps is greater than the number of accessible branches. In this case, each accessible branch can be clamped with a current clamp, and the processor 108 can still calculate the resistance of each accessible branch.

[0059] In one embodiment, the number of current clamps is one less than the number of accessible branches. In this case, the number of current clamps cannot cover all accessible branches, and there is a accessible branch where the current clamp is not set, which is called an unknown branch. The accessible branch directly set by the current clamp is called a known branch, and the voltage measurement module 102 is set at both ends of the known branch, the first current source clamp of the current source measurement module is set in the circuit loop, and the second current source clamp of the current source measurement module is set in the known branch. Through the steps recorded above, the processor 108 can calculate the resistance of the known branch, and combined with the circuit principle, the resistance of the unknown branch can be calculated.

[0060] In practical applications, first, the dedicated test line is connected to the clamp and the processor 108 according to the color of the mark, red to red, black to black, and the test line is used to connect the clamp and the processor 108. The thicker current line in the dedicated test line is connected to the corresponding I+, I- terminal and tightened, and the thinner voltage line is connected to the V+, V- terminal and tightened. Each current clamp is set at each known branch, the first current source clamp is set at the circuit loop, the second current source clamp is set at the specified known branch, and the two voltage clamps are set at the specified known branch. After starting the resistance measuring device, the user selects the current clamp mode and measures the resistance of each accessible branch. When the current clamp mode is selected, the user can start the measurement by pressing the test button. The current source data of the current source module 106 is first displayed on the display screen, and the prompt "testing" can be prompted at the same time. Then the processor 108 calculates the resistance of each known branch and the current parameters of each known resistance, and displays them on the display screen. Further, when the user presses the test button to start the measurement, the display screen can start to display the timing at the same time, and the timing stops when the display screen displays the resistance of the known branch. For example, the resistance of the measured known branch, the current value output by the current source module 106, the current parameters of each known resistor, and the time taken to calculate the resistance can be displayed on the display screen at the same time. Exemplarily, the content displayed by the display module includes: the current of the first known branch is 35.72A, and the corresponding resistance is 202.3 microohms; the current of the second known branch is 35.72A, and the corresponding resistance is 202.3 microohms; the current of the third known branch is 35.72A, and the corresponding resistance is 202.3 microohms. The current used for the current source measurement is 99.76A, and this measurement takes 17 seconds.

[0061] Further, after obtaining the measured resistance of the known branch, the display screen can update the displayed data in real time, that is, the detection time increases with the display time, and the measured resistance of the known branch and the current used for current source measurement change in real time. After the test is completed, the reset button can be pressed, the current source module 106 stops the current output, and the display screen is reset.

[0062] Furthermore, the user can control the processor 108 to calculate and display the resistance of the unknown branch through the interactive module 110 , that is, calculate the resistance of the unknown branch according to the current and resistance and the voltage parameter of the voltage measurement module 102 .

[0063] In one embodiment, the circuit under test further includes an inaccessible branch, each current clamp is respectively arranged on an accessible branch connected to the inaccessible branch, the current source module 106 is arranged on the circuit under test, and the voltage measurement module 102 is arranged on the inaccessible branch.

[0064] Among them, the inaccessible branch is a branch where the current measurement module 104 cannot be directly set, such as a contact surface branch. At this time, the current clamp cannot be directly set on the inaccessible branch, the magnitude and direction of the current in the inaccessible branch are unknown, and the total loop of the circuit under test cannot be determined. In this case, the flow path relationship of the circuit under test is complex, and the current source module 106 can be set at any position of the circuit under test, and different branches in the circuit under test can obtain current.

[0065] Therefore, each current clamp can be set on a contactable branch connected to an incontactable branch to detect the current parameters of the corresponding contactable branch. The local simplified equivalent diagram of the measured circuit is shown in Figures 5 and 6. The contactable branch is connected to the incontactable branch at point a. A current clamp with a current measurement module 104 is set on the contactable branch connected to the incontactable branch to obtain current I1 and current I2 respectively. At the same time, the voltage measurement module 102 is set at both ends of the resistance to be measured, that is, the two ends of the incontactable branch, to obtain the voltage U. The branch resistance to be measured is the resistance R, and the current on the branch resistance to be measured is the current I, both of which are parameters that cannot be directly measured. Since the direction of the current in each branch is not fixed, the two situations shown in Figures 5 and 6 and other situations may occur. Taking Figures 5 and 6 as examples, the resistance calculation process under this mode is analyzed.

[0066] Since the resistor R is in a branch where the current clamp cannot be used, the magnitude and direction of the current I are unknown, and the voltage U can be directly measured by the voltage measurement module 102. In the calculation process, it is assumed that the current directions of the three branches (including the accessible branch and the inaccessible branch) are the same as those shown in the figure, and the current values ​​are all positive. Then, for the schematic diagram shown in Figure 5, I=I1+I2, so the value of the resistor R can be calculated by R=U / (I1+I2). For the schematic diagram shown in Figure 6, I2=I+I1, so I=I2-I1, and the resistance value of the resistor R can be calculated by R=U / (I2-I1).

[0067] According to the above principle, when using the current clamp to measure the resistance of the inaccessible branch, the user faces the clamping direction of the current clamp to the point a where the branches meet. At this time, the general measurement formula of the resistance measured is R=U / (|I1+I2|), where the values ​​of I1 and I2 have a win or loss, and the absolute value is removed to refine the formula: if both currents are positive or negative, then R=U / (|I1|+|I2|), if one of the two currents is negative, then R=U / (||I1|+|I2||), where I1 and I2 have a positive or negative. For example, if I1=4A, I2=2A, then |I|=6A, if I1=2A, I2=-4A, then I=-2A, |I|=2A.

[0068] The processor 108 calculates the resistance measurement result of the specified branch according to the above processing logic combined with the obtained circuit parameters. The user can select the special branch mode when starting the resistance measuring device to measure the resistance of the specified inaccessible branch. After the special branch mode is selected, the user can measure by pressing the test key. The current source data of the current source module 106 is first displayed on the display screen, and a prompt "testing" can be prompted at the same time. Then the processor 108 calculates the resistance measurement result of the specified branch and displays it on the display screen. Furthermore, when the user presses the test key to start the measurement, the display screen can start to display the timing at the same time, and the timing stops when the display screen displays the branch resistance.

[0069] In this embodiment, by recording various modes of the resistance measuring device and describing in detail the setting methods and resistance calculation principles corresponding to each mode, the user can choose any one according to the needs, so that the resistance measuring device can be applied to a variety of resistance measurement occasions, and can perform resistance detection on circuits with branches with multiple contact surfaces, thereby improving the applicability of the resistance measuring device.

[0070] In one embodiment, the resistance measurement device applied to any parallel branch of a primary device further includes a communication module, and the processor 108 is connected to the voltage measurement module 102, the current measurement module 104 and the current source module 106 via the communication module.

[0071] Specifically, the processor 108 stores a variety of communication protocols, and can establish communication channels for the voltage measurement module 102, the current measurement module 104, and the current source module 106, respectively, so as to obtain the corresponding circuit parameters. Further, the communication module stores a variety of communication protocols, and the communication module can establish communication channels with the voltage measurement module 102, the current measurement module 104, and the current source module 106, respectively, and transmit the corresponding circuit parameters to the processor 108 during the interaction with the processor 108. By setting the communication module to complete the communication interaction between each module and the processor 108, it is conducive to ensuring the stable establishment of the communication channel and the stability and reliability of data transmission.

[0072] In order to better understand the above solution, a detailed explanation is given below in conjunction with a specific embodiment.

[0073] In one embodiment, a resistance measuring device applied to any parallel branch of a primary device is shown in FIG2 , and a user will use the resistance measuring device to measure the contact surface resistance of a scissor-type knife switch. The structure of the scissor-type knife switch is shown on the left side of Figure 7. The 500kV GW6A-550 scissor-type knife switch has a set of two scissors, and the moving and static contacts have a structure with four contact surfaces in parallel. When it is necessary to measure the resistance of one of the contact surfaces (the contact surface to be measured), since the four contact surfaces of the knife switch have a non-detachable parallel structure, when the equivalent circuit diagram of the scissor-type knife switch is shown in Figure 8, the circuit of the scissor-type knife switch can be equivalent to multiple parallel-connected branches with different hierarchical connection relationships. For example, in Figure 8, resistors R11 and R12 belong to the contact surface resistance of the aluminum stranded wire under the busbar, resistors R21, R22, R23 and R24 belong to the contact surface resistance of the main conductive arm, resistors R31, R32 and R33 belong to the contact surface resistance of the arc-starting rod, resistors R41, R42, R43 and R44 belong to the contact surface resistance of the conductive belt, and R5 belongs to the contact surface resistance of the terminal board. The connection relationship between the resistors is shown in the figure, and multiple levels are connected in parallel to form different branches. Among them, different resistors require the resistance measuring device to be set up accordingly and measure the circuit parameters respectively, so as to accurately measure the resistance of different contact surfaces in the knife switch.

[0074] In traditional circuit resistance detection instruments, as shown on the right side of Figure 7, when measuring the resistance of the contact surface to be measured pointed by the arrow, the current source clamp can only be clamped on the conductive arm and other contact surface branches. No matter where the current source clamp is clamped to the conductive arm of the knife switch, current shunt will occur due to the parallel characteristics. Therefore, the current on the single contact surface to be measured is not the power supply current, which results in a scenario where the single contact surface resistance cannot be accurately measured.

[0075] The resistance measuring device used in this embodiment for any parallel branch of a primary device uses a current clamp made of a Hall current loop element to clamp at other positions. No matter which point the current source module is clamped into, since the contact surface to be measured can be regarded as one point and three branches, the current flowing through the contact surface can be obtained by measuring the current of any two branches of the contact surface. Therefore, the other two contactable branches are provided with current clamps to detect the current, and the current flowing through the contact surface can be calculated to obtain the contact surface resistance. As shown in Figure 9, taking one side of the conductive arm of the knife switch as an example, as long as I1 and I2 or I6 and I7 are measured, the current I on R1 and R2 can be calculated, and then R1 and R2 can be obtained by measuring the voltage at both ends of the contact surface on the knife switch device (the device voltage is easy to measure in actual working conditions).

[0076] During the measurement process, first connect the dedicated test line according to the marked color, red to red, black to black, use the test line to connect the clamp and the processor, connect the thicker current line in the dedicated test line to the corresponding I+, I- terminals and tighten, and connect the thinner voltage line to the V+, V- terminals and tighten. The position of the current source clamp (the two larger clamps in the figure) is shown in Figure 10, clamped on the conductive arm and other contact surface branches, and then the current clamp (the two smaller clamps in the figure) is set on different contact surface branches. The voltage measurement module (not shown in the figure) directly measures the voltage across the contact surface resistance to be measured. The processor obtains the corresponding circuit parameters and calculates the contact surface resistance to be measured.

[0077] The traditional loop resistance meter is suitable for a single resistance system where the primary device is connected to a non-closed and non-parallel connection. Its design is more inclined to measure the overall return resistance of a single device, rather than a more in-depth resistance measurement of each point surface. In this embodiment, a breakthrough is made in the situation where the traditional loop resistance tester cannot measure multi-branch resistance. In the face of a more complex structure of power equipment connection, it can also measure the contact resistance of a certain power equipment connection surface. In addition, during the measurement process, the direction of the current can be identified. Under extremely complex working conditions (such as when there is a branch that cannot be directly measured), the branch current that cannot be directly measured can be calculated by measuring other branch currents, thereby obtaining the branch resistance, which greatly improves the applicability of the resistance measurement device.

[0078] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic description of the above terms does not necessarily refer to the same embodiment or example.

[0079] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A resistance measuring device applied to any parallel branch of a primary device, characterized in that: It includes a voltage measurement module, a current measurement module, a current source module and a processor, wherein the voltage measurement module, the current measurement module and the current source module are all connected to the processor; The current source module, the voltage measurement module and the current measurement module are all arranged in the circuit under test, and are used to obtain circuit parameters and send them to the processor, and the processor is used to determine the resistance parameters of the circuit under test according to the circuit parameters.

2. The resistance measuring device for any parallel branch of a primary device according to claim 1, characterized in that: The current source module includes a first current source clamp and a second current source clamp, both of which are connected to the processor, the first current source clamp is arranged at the first end of the circuit under test, and the second current source clamp is arranged at the second end of the circuit under test.

3. The resistance measuring device for any parallel branch of a primary device according to claim 1, characterized in that: The current measurement module includes a plurality of current clamps, and each of the current clamps is connected to the processor.

4. The resistance measuring device for any parallel branch of a primary device according to claim 3, characterized in that: The circuit under test includes a main loop and more than two accessible branches, each current clamp is respectively arranged at each accessible branch, the current source module is arranged at the main loop and any of the accessible branches, and the voltage measurement module is arranged at any of the accessible branches.

5. The resistance measuring device applied to any parallel branch of a primary device according to claim 4, characterized in that: The number of the current clamps matches the number of the accessible branches.

6. The resistance measuring device for any parallel branch of a primary device according to claim 4, characterized in that: The number of the current clamps is one less than the number of the contactable branches.

7. The resistance measuring device applied to any parallel branch of a primary device according to claim 4, characterized in that: The circuit under test also includes an inaccessible branch, each of the current clamps is respectively arranged on a accessible branch connected to the inaccessible branch, the current source module is arranged on the circuit under test, and the voltage measurement module is arranged on the inaccessible branch.

8. The resistance measuring device applied to any parallel branch of a primary device according to claim 1, characterized in that: The current measurement module is a Hall current loop element.

9. The resistance measuring device applied to any parallel branch of a primary device according to claim 1, characterized in that: The device further includes an interaction module, and the interaction module is connected to the processor.

10. The resistance measuring device applied to any parallel branch of primary equipment according to claim 1, characterized in that: The device further includes a communication module, and the processor is connected to the voltage measurement module, the current measurement module and the current source module through the communication module.

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