Secondary wire checking device and method of current transformer

Abstract

The invention provides a secondary wire checking device and method of a current transformer, and relates to the technical field of wire checking. The secondary wire checking device of the current transformer comprises a plurality of resistance measurement interfaces which are used for being connected with a plurality of current terminal strip test interfaces of an electric control cabinet in a one-to-one correspondence mode so as to be used for measuring resistance values of branches corresponding to the current terminal strip test interfaces; the measuring line common end is used for being connected with an equipotential ground bar of an electric control cabinet so as to connect the secondary line checking device of the current transformer with the electric control cabinet; and a result display assembly which is connected with the plurality of resistance measurement interfaces and is used for receiving and displaying the resistance values of the branches corresponding to the plurality of current terminal strip test interfaces.

Description

Technical Field

[0001] The present application relates to the field of line calibration technology, and in particular to a secondary line calibration device and method for a current transformer. Background Art

[0002] At present, in substation systems of various voltage levels, current transformers use the principle of electromagnetic induction to convert large currents on the primary side into small currents on the secondary side for use by secondary equipment. Current transformers play the role of isolation, safety, accuracy, and speed, ensuring the reliable and stable operation of the power grid. Among them, for new, modified and expanded substation current transformers, secondary commissioning personnel usually disassemble the secondary terminal cores of each winding in the current transformer body terminal box, and then short-circuit the ground to calibrate the correctness of the secondary cable core connection between the current transformer and the control cabinet. However, during the verification process, if the operation is improper, it is easy to have the risk of loosening, opening, breaking, and restoring wiring errors of the winding terminals of the current transformer body terminal box, resulting in the secondary monitoring and protection devices being unable to correctly reflect the actual operation of the primary equipment, causing the circuit breaker protection device to refuse to operate or malfunction, leaving safety hazards for the smooth commissioning of the substation, and seriously threatening the safe and stable operation of the power grid.

[0003] Therefore, how to provide a line calibration device that reduces potential safety hazards has become an urgent problem to be solved. Summary of the invention

[0004] A technical problem to be solved by the present application is: how to provide a line calibration device that reduces potential safety hazards.

[0005] In order to solve the above technical problems, the embodiment of the present application provides a secondary calibration device for a current transformer, comprising:

[0006] A plurality of resistance measurement interfaces, the plurality of resistance measurement interfaces are used to be connected one-to-one with a plurality of current terminal block test interfaces of the electric control cabinet, so as to measure the resistance values ​​of the branches corresponding to the plurality of current terminal block test interfaces;

[0007] A common end of the measuring line, which is used to connect to the equipotential ground bar of the electric control cabinet to connect the secondary calibration device of the current transformer to the electric control cabinet;

[0008] A result display component is connected to the multiple resistance measurement interfaces respectively, and is used to receive and display the resistance values ​​of the branches corresponding to the multiple current terminal block test interfaces.

[0009] In some embodiments, it also includes:

[0010] A shell, the outer surface of which is provided with a plurality of the resistance measurement interfaces, the common end of the measurement lines and a result display component.

[0011] A controller is disposed in the shell, and the controller is connected to the multiple resistance measurement interfaces and the result display component to receive the resistance values ​​of the multiple branches transmitted by the multiple resistance measurement interfaces, convert the resistance values ​​of the multiple branches and transmit them to the result display component for display.

[0012] In some embodiments, the result display component includes:

[0013] A display screen, the display screen is arranged on the outer surface of the housing, the display screen is connected to the controller to receive and display the resistance values ​​of the multiple branches converted by the controller; and

[0014] A speaker is arranged on the outer surface of the shell and is connected to the controller to receive and broadcast the branch with the smallest resistance value among multiple branches.

[0015] In some embodiments, the result display component further includes:

[0016] Multiple warning lights are arranged on the outer surface of the shell, and the multiple warning lights are arranged in a one-to-one correspondence with the multiple resistance measurement interfaces. The warning lights are connected to the controller, and the controller is used to control the brightness of the corresponding warning lights according to the resistance value.

[0017] In some embodiments, the controller includes:

[0018] A conversion unit, the conversion unit being connected to the resistance measurement interface and configured to receive resistance values ​​of a plurality of branches and convert the resistance values ​​into digital signals;

[0019] A connecting unit, the connecting unit is connected to the converting unit and is used to receive the digital signal transmitted by the converting unit;

[0020] A logic processing unit, connected to the connection unit, for processing and comparing the plurality of digital signals to obtain a branch corresponding to a minimum resistance value;

[0021] An output unit is connected to the logic processing unit, and the output unit is connected to the display screen and the speaker to send the resistances of the multiple branches to the display screen for display, and transmit the branch with the smallest resistance value to the speaker for playback.

[0022] In some embodiments, the controller further comprises:

[0023] A storage unit is connected to the connection unit to store digital signals of multiple branches received by the connection unit, and to receive and store branch information of the minimum resistance value processed by the logic processing unit through the connection unit.

[0024] In some embodiments, the controller further comprises:

[0025] A system control unit, the system control unit is connected to the connection unit to receive the digital signal transmitted by the connection unit;

[0026] An external transmission unit, the external transmission unit is connected to the system control unit, and is used to receive the digital signal and transmit the digital signal to the outside world.

[0027] In some embodiments, it also includes:

[0028] A switch component is connected to the controller to control the controller to be turned on or off.

[0029] In a second aspect, the present application also provides a secondary calibration method for a current transformer, comprising:

[0030] Connect multiple terminals of the current transformer junction box to multiple current terminal blocks of the electric control cabinet in sequence;

[0031] Connecting the multiple resistance measurement interfaces of the secondary calibration device of the current transformer to the multiple current terminal block test interfaces of the electric control cabinet one by one;

[0032] Connecting the common end of the measuring line of the secondary calibration device of the current transformer to the equipotential ground bar of the electric control cabinet;

[0033] Connect multiple terminals of the current transformer junction box to the equipotential ground bar of the electric control cabinet in sequence, so as to calibrate the multiple terminals in sequence.

[0034] In some embodiments, before sequentially connecting the plurality of terminals of the current transformer junction box to the plurality of current terminal blocks of the electric control cabinet, the method includes: checking the tightness of the plurality of terminals of the current transformer junction box.

[0035] Through the above technical scheme, the present application provides a secondary calibration device and method for a current transformer. When calibrating the terminal posts of the current transformer, it is only necessary to connect the terminal posts corresponding to the terminal posts to be calibrated in the terminal box of the current transformer to the equipotential ground bar of the electric control cabinet. The calibration method is simple and convenient, easy to operate, and does not require disassembling the winding core of the current transformer terminal box. Therefore, the risks of terminal damage, core restoration errors, and secondary circuit open caused by disassembling the secondary wire at the terminal box of the current transformer can be effectively reduced, and the efficiency and quality of on-site debugging can be significantly improved, which avoids the secondary monitoring and protection devices from failing to correctly reflect the actual operation of the primary equipment, causing the circuit breaker protection device to refuse to operate or malfunction, leaving safety hazards for the smooth commissioning of the substation, reducing safety hazards, and allowing the power grid to operate safely and stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be 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 paying creative work.

[0037] Figure 1 It is a structural schematic diagram of a secondary calibration device of a current transformer disclosed in an embodiment of the present application;

[0038] Figure 2 It is a circuit diagram of a secondary calibration device of a current transformer disclosed in an embodiment of the present application;

[0039] Figure 3 It is a connection and structural diagram of a controller in a secondary calibration device of a current transformer disclosed in an embodiment of the present application;

[0040] Figure 4 This is a schematic diagram of the connection between a current transformer and a control cabinet disclosed in an embodiment of the present application;

[0041] Figure 5 It is a flow chart of a secondary calibration method of a current transformer disclosed in an embodiment of the present application;

[0042] Figure 6 It is a flow chart of another secondary calibration method of a current transformer disclosed in an embodiment of the present application.

[0043] Description of reference numerals:

[0044] 1. Secondary calibration device of current transformer; 11. Resistance measurement interface; 12. Common end of measurement line; 13. Result display component; 131. Display screen; 132. Speaker; 133. Prompt light; 14. Housing; 15. Controller; 151. Conversion unit; 152. Connection unit; 153. Logic processing unit; 154. Output unit; 155. Storage unit; 156. System control unit; 157. External transmission unit; 158. Reset unit; 16. Switch component; 2. Current transformer; 21. Junction box; 22. Terminal post; 3. Control cabinet; 31. Current terminal block; 32. Moving slider part of terminal block; 33. Static part of terminal block; 34. Terminal block test interface. DETAILED DESCRIPTION

[0045] The following is a further detailed description of the implementation methods of the present application in conjunction with the accompanying drawings and examples. The detailed descriptions of the following examples and the accompanying drawings are used to exemplarily illustrate the principles of the present application, but cannot be used to limit the scope of the present application. The present application can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

[0046] The present application provides these embodiments to make the present application thorough and complete, and to fully express the scope of the present application to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values ​​set forth in these embodiments should be interpreted as being merely exemplary, and not as limiting.

[0047] It should be noted that, in the description of this application, unless otherwise specified, the meaning of "multiple" is greater than or equal to two; the terms "upper", "lower", "left", "right", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0048] In addition, the words "first", "second" and the like used in this application do not indicate any order, quantity or importance, but are only used to distinguish different parts. "Vertical" is not strictly perpendicular, but within the tolerance range. "Parallel" is not strictly parallel, but within the tolerance range. "Include" or "comprising" and the like words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of also including other elements.

[0049] It should also be noted that in the description of this application, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. When a specific device is described as being located between a first device and a second device, there may or may not be an intermediate device between the specific device and the first device or the second device.

[0050] All terms used in this application have the same meaning as those understood by those of ordinary skill in the art to which this application belongs, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries, such as general dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or extremely formal sense, unless explicitly defined herein.

[0051] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0052] like Figure 1 The present application provides a secondary calibration device 1 for a current transformer, comprising:

[0053] A plurality of resistance measurement interfaces 11, the plurality of resistance measurement interfaces 11 are used to be connected one-to-one with a plurality of current terminal blocks 31 test interfaces of the electric control cabinet, so as to measure the resistance values ​​of the branches corresponding to the plurality of current terminal blocks 31 test interfaces;

[0054] A measuring line common terminal 12, the measuring line common terminal 12 is used to connect to the equipotential ground bar of the electric control cabinet, so as to connect the secondary calibration device 1 of the current transformer with the electric control cabinet;

[0055] The result display component 13 is connected to the multiple resistance measurement interfaces 11 respectively, and is used to receive and display the resistance values ​​of the branches corresponding to the multiple current terminal block 31 test interfaces.

[0056] In this embodiment, the current transformer 2 of the newly built, renovated and expanded substation needs to be calibrated. In the related technology, the secondary debugging personnel usually disassemble the cores of the secondary terminals 22 of each winding of the terminal box 21 of the current transformer 2, and short-circuit them to the ground to calibrate the correctness of the one-to-one correspondence with the secondary cable cores of the three control cabinets. If this calibration method is not operated properly, it is easy to cause the risks of the winding terminals 22 of the terminal box 21 of the current transformer 2 to become loose, open circuit, break, or restore the wiring error, resulting in the secondary monitoring and protection devices being unable to correctly reflect the actual operation of the primary equipment, causing the circuit breaker protection device to refuse to operate or malfunction, leaving safety hazards for the smooth commissioning of the substation, and seriously threatening the safe and stable operation of the power grid. Therefore, the present application provides a secondary calibration device 1 for a current transformer, which can effectively reduce the number of operations of secondary debugging personnel and improve the accuracy and work efficiency of calibration.

[0057] like Figure 4 As shown, in this embodiment, the current transformer 2 usually has multiple secondary windings with different transformation ratios, which are used by secondary equipment such as protection, measurement, and metering through the secondary cable loop. Usually, in conventional substations and smart substations with a voltage level of 110 kV and above, conventional sampling of currents of different groups adopts the form of phase-separated wiring, that is, the three phases A / B / C of the same group are respectively connected to the current terminal block 31 of the control cabinet 3. The current transformer 2 includes a secondary winding terminal box 21, in which a plurality of secondary wire terminals 22 are arranged. The secondary wire terminals 22 are fixed to the secondary cable core by bolts or screws, and the terminals 22 are connected to the control cabinet 3 through the secondary cable.

[0058] like Figure 4 As shown, in this embodiment, the control cabinet 3 includes a current terminal block 31, a terminal block movable slider part 32, a terminal block static part 33 and a terminal block test interface 34. The current terminal block 31 is used to connect with the terminal posts 22 of the three-phase current transformer 2 body terminal box 21 through secondary cables from top to bottom; the terminal block movable slider part can slide left and right by screwing with a flat-blade screwdriver to realize the left and right switching of the terminal block; when the terminal block movable slider part 32 slides to the right and is tightened, the terminal block is turned on left and right, and when the terminal block movable slider part 32 slides to the left, the terminal block is disconnected left and right to achieve isolation; the terminal block test interface 34 is for the test line to be connected to it.

[0059] like Figure 1 , Figure 2 and Figure 4As shown, in this embodiment, the current transformer 2 is arranged at one place, the control cabinet 3 and the secondary calibration device 1 of the current transformer are arranged at another place, the A debugging personnel is located at the location of the current transformer 2, and the B debugging personnel is located at the location of the control cabinet 3 and the secondary calibration device 1 of the current transformer. The debugging personnel confirm that the interval is in a non-operating state, and after measuring and testing the electricity, the interval is not energized. The A debugging personnel opens the junction box 21 of the current transformer 2 with a wrench at the current transformer 2, checks the tightness of the wiring of each terminal 22, and then connects the multiple secondary terminals 22 of the junction box 21 of the current transformer 2 with the multiple current terminal blocks 31 from top to bottom of the control cabinet 3 through a multi-core secondary cable. The A debugging personnel holds a single-core metal wire with bare insulation at both ends, one end of which is connected to the equipotential ground bar, and the other end is waiting to be short-circuited with the metal columns of each winding in the junction box 21 of the current transformer 2. Debugger B uses a screwdriver to slide open the movable slider of the A / B / C three-phase current terminal block 31 at the control cabinet 3 in sequence, including the grounding wires of each winding. Debugger B then connects the common end 12 of the measurement line of the secondary calibration device 1 of the current transformer to the equipotential grounding bar of the electric control cabinet, and uses the test board line to connect multiple resistance measurement interfaces 11 to the test interfaces of the current terminal block 31 one by one. At this time, the result display component 13 shows that the resistance value of each branch is OL, and OL means that the resistance value is infinite. At this time, the status of the secondary calibration device 1 of the electric control cabinet and the current transformer is normal. The debugger can start to calibrate the current transformer 2.

[0060] In this embodiment, the specific connection form in which multiple resistance measurement interfaces 11 are connected to the current terminal block 31 test interface in a one-to-one correspondence is: K11 in the resistance measurement interface 11 of the secondary calibration device 1 of the current transformer is connected to A1S1 at the test interface number 1 of the current terminal block 31 of the electric control cabinet, K12 in the resistance measurement interface 11 of the secondary calibration device 1 of the current transformer is connected to A1S2 at the test interface 5 of the current terminal block 31 of the electric control cabinet, K13 in the resistance measurement interface 11 of the secondary calibration device 1 of the current transformer is connected to A1S3 at the test interface 9 of the current terminal block 31 of the electric control cabinet, K21 in the resistance measurement interface 11 of the secondary calibration device 1 of the current transformer is connected to A2S1 at the test interface 13 of the current terminal block 31 of the electric control cabinet, K22 is connected to A2S2 at the serial number 17 of the current terminal block 31, K23 is connected to A2S3 at the serial number 21 of the current terminal block 31, and the same applies to other windings.

[0061] like Figure 1 , Figure 2 and Figure 4As shown, the present application provides a secondary calibration device 1 for a current transformer, comprising a plurality of resistance measurement interfaces 11, a measurement line common end 12 and a result display component 13, wherein the plurality of resistance measurement interfaces 11 are used to be connected one-to-one with a plurality of current terminal blocks 31 test interfaces of an electric control cabinet, the measurement line common end 12 is used to be connected with the equipotential ground bar of the electric control cabinet, and the equipotential ground bar of the electric control cabinet is connected with the plurality of current terminal blocks 31 test interfaces of the electric control cabinet, thereby realizing the connection between the plurality of resistance measurement interfaces 11 and the measurement line common end 12, so as to connect the current transformer 2 with the electric control cabinet. The result display component 13 is connected with the plurality of resistance measurement interfaces 11, so as to receive and display the resistance values ​​of the branches corresponding to the plurality of current terminal blocks 31 test interfaces. When calibrating the current transformer 2, debugging personnel A connects the metal wire with one end connected to the equipotential ground bar to the A1S1 terminal 22 at the terminal box 21 of the current transformer 2 body. At this time, debugging personnel B checks the resistance of each branch displayed at the result display component 13 of the secondary calibration device 1 of the current transformer. If the resistance of each branch is consistent with the terminal 22 short-circuited by debugging personnel A, the calibrated wire core is correct and the next wire core is tested. If the resistance of each branch is inconsistent with the terminal 22 short-circuited by debugging personnel A, debugging personnel A adjusts the position of the short-circuited terminal 22 until the resistance of each branch is consistent with the terminal 22 short-circuited by debugging personnel A. According to the above method, the A1S2 terminal 22, A1S3 terminal 22, A2S1 terminal 22, A2S2 terminal 22, A2S3 terminal 22, A3S1 terminal 22, A3S2 terminal 22, A3S3 terminal 22, A4S1 terminal 22, A4S2 terminal 22 and A4S3 terminal 22 of the current transformer 2 are tested in sequence.

[0062] In this embodiment, when calibrating the current transformer through the secondary calibration device 1, the A debugging personnel connects the metal wire connected to the equipotential ground bar at one end to the A1S1 terminal 22 at the terminal box 21 of the current transformer 2 body, and the B debugging personnel checks the resistance of each branch displayed at the result display component 13 of the secondary calibration device 1 of the current transformer. If the resistance of each branch is consistent with the terminal 22 short-circuited by the A debugging personnel, the resistance of K11 is the smallest at this time, and the resistance of other branches is greater than the resistance of K11. At this time, it can be confirmed that the A debugging personnel short-circuited the wire core connected to the A1S1 terminal 22. The A debugging personnel removed the short-circuit wire at the A1S1 terminal 22, and the resistance of each branch returned to display OL. After that, the A debugging staff connected the metal wire connected to the equipotential ground bar at one end to the A1S2 terminal 22 at the terminal box 21 of the current transformer 2. At this time, the B debugging staff observed the resistance of each branch displayed on the result display component 13. At this time, the resistance of K12 was the smallest, and the resistance of other branches was greater than that of K12. At this time, it can be confirmed that the wire connected to the A1S2 terminal 22 was short-circuited to the ground by the A debugging staff. The same applies to other wires.

[0063] In this embodiment, if there is a wiring error, when commissioning personnel A connects the metal wire whose one end is connected to the equipotential ground bar to the terminal 22A1S1 at the terminal box 21 of the current transformer 2, two situations may occur in the secondary calibration device 1 of the current transformer. In the first case, if the A debugging personnel first short-circuit the A1S1 terminal 22 to the ground at the junction box 21 of the current transformer 2 and keep it, then the B debugging personnel observes that the resistance values ​​corresponding to the multiple branches of the result display component 13 except K11 are normal. The possible wiring error is that the positions of the wire cores at both ends are staggered. At this time, the debugging personnel need to confirm the wire core number, adjust the wiring after it is correct, and then re-calibrate the wire; in the second case, if the A debugging personnel first short-circuit the A1S1 terminal 22 to the ground at the junction box 21 of the current transformer 2 body, then the B debugging personnel observes that all branches of the result display component 13 show that the OL resistance value is infinite. In this case, the wiring error may be that one end of a wire core is suspended and not connected. In addition to checking whether the wire core numbers are consistent, the multimeter is used to find the same wire core on the spare cores or terminal blocks at both ends, and correctly connect them to the corresponding positions, and then re-calibrate the wire. After the secondary cores of each winding of phase A are correctly calibrated according to this method, the secondary wires of the current transformer 2 of phase B and phase C can then be calibrated in the above manner.

[0064] Therefore, the secondary calibration device 1 of the current transformer provided in the present application only needs to connect the terminal 22 to be calibrated in the terminal box 21 of the current transformer 2 to the equipotential ground bar of the electric control cabinet when calibrating the terminal 22 of the current transformer 2. The calibration method is simple and convenient, easy to operate, and there is no need to disassemble the winding core of the terminal box of the current transformer 2. Therefore, the risks of damage to the terminal 22, restoration of the wire core error, and open circuit of the secondary circuit caused by disassembling the secondary wire at the terminal box of the current transformer 2 can be effectively reduced, which significantly improves the efficiency and quality of on-site debugging, avoids the secondary monitoring and protection devices from failing to correctly reflect the actual operation of the primary equipment, causing the circuit breaker protection device to refuse to operate or malfunction, leaving safety hazards for the smooth commissioning of the substation, reduces safety hazards, and enables the power grid to operate safely and stably.

[0065] like Figure 1 As shown, in the embodiment of the present application, it also includes:

[0066] The housing 14 has a plurality of resistance measurement interfaces 11 , a measurement line common terminal 12 and a result display component 13 disposed on its outer surface.

[0067] A controller 15 is disposed in the housing 14 and is connected to the plurality of resistance measurement interfaces 11 and the result display component 13 to receive resistance values ​​of the plurality of branches transmitted by the plurality of resistance measurement interfaces 11, and transmit the resistance values ​​of the plurality of branches to the result display component 13 for display.

[0068] In this embodiment, the secondary calibration device 1 of the current transformer includes a plurality of resistance measurement interfaces 11, a measurement line common end 12, a result display component 13, a housing 14 and a controller 15. The housing 14 is provided with a controller 15, and the outer surface of the housing 14 is provided with a plurality of resistance measurement interfaces 11, a measurement line common end 12 and a result display component 13, so that the plurality of resistance measurement interfaces 11 and the measurement line common end 12 can be connected to the electric control cabinet, and the result display component 13 can display the resistance value of each branch for the convenience of the debugging personnel to view. The housing 14 is also provided with a controller 15, and the controller 15 is respectively connected to the plurality of resistance measurement interfaces 11 and the result display component 13, so that the plurality of resistance values ​​from the plurality of resistance measurement interfaces 11 can be received, and the plurality of resistance values ​​are converted to be sent to the result display component 13, and displayed through the result display component 13 for the convenience of the debugging personnel to view.

[0069] like Figure 1 and Figure 2 As shown, in the embodiment of the present application, the result display component 13 includes:

[0070] A display screen 131, which is disposed on the outer surface of the housing 14 and is connected to the controller 15 to receive and display the resistance values ​​of the multiple branches converted by the controller 15; and

[0071] The speaker 132 is disposed on the outer surface of the housing 14 and is connected to the controller 15 to receive and broadcast the branch with the smallest resistance value among the multiple branches.

[0072] In this embodiment, the result display component 13 includes a display screen 131 and a speaker 132, and the display screen 131 and the speaker 132 are both connected to the controller 15, and the controller 15 is connected to multiple resistance measurement interfaces 11, so that the controller 15 can receive the resistance values ​​of multiple branches from the multiple resistance measurement interfaces 11, and the controller 15 converts the resistance values ​​so that the display screen 131 can display the resistance values ​​of multiple branches, so that the debugging personnel can check the resistance values ​​of multiple branches, so as to calibrate the terminal 22 of the current transformer 2 according to the resistance values ​​of each branch. And the controller 15 can also confirm the branch with the minimum resistance value according to the resistance values ​​of multiple branches, and transmit the branch information with the minimum resistance to the speaker 132, and the speaker 132 will broadcast the branch with the minimum resistance, so as to further facilitate the debugging personnel to confirm the branch with the minimum resistance and improve the efficiency of calibration.

[0073] like Figure 1 As shown, in the embodiment of the present application, the result display component 13 also includes:

[0074] A plurality of indicator lights 133 are disposed on the outer surface of the shell 14, the plurality of indicator lights 133 are disposed in one-to-one correspondence with the plurality of resistance measurement interfaces 11, the indicator lights 133 are connected to the controller 15, and the controller 15 is used to control the brightness of the corresponding indicator lights 133 according to the resistance value.

[0075] In this embodiment, the result display component 13 also includes multiple prompt lights 133, and the multiple prompt lights 133 are correspondingly arranged below, above or on the sides of the multiple resistance measurement interfaces 11, so as to display the resistance of the branch where the corresponding resistance measurement interface 11 is located. When the corresponding resistance is smaller, the controller 15 controls the brightness of the prompt light 133 to be brighter, and when the corresponding resistance is larger, the controller 15 controls the brightness of the prompt light 133 to be lower, so that the debugging personnel can judge the resistance value of the branch resistance according to the brightness of the corresponding prompt light 133.

[0076] like Figure 2 and Figure 3 As shown, in the embodiment of the present application, the controller 15 includes:

[0077] A conversion unit 151, the conversion unit 151 is connected to the resistance measurement interface 11, and is used to receive resistance values ​​of multiple branches and convert the resistance values ​​into digital signals;

[0078] a connecting unit 152, the connecting unit 152 being connected to the converting unit 151 and being configured to receive a digital signal transmitted by the converting unit 151;

[0079] A logic processing unit 153, the logic processing unit 153 is connected to the connection unit 152, and is used to process and compare the multiple digital signals to obtain a branch corresponding to a minimum resistance value;

[0080] The output unit 154 is connected to the logic processing unit 153, and the output unit 154 is connected to the display screen 131 and the speaker 132 to send the resistances of the multiple branches to the display screen 131 for display, and transmit the branch with the smallest resistance value to the speaker 132 for playback.

[0081] In this embodiment, the controller 15 includes a conversion unit 151, a connection unit 152, a logic processing unit 153 and an output unit 154. The conversion unit 151 is a multi-channel AD analog-to-digital conversion unit 151 to convert the resistance values ​​of multiple branches into digital signals. The connection unit 152 is a bus matrix for realizing coordinated access of instructions, control, data and other information between the core and peripherals and storage. The logic processing unit 153 receives the resistance of each branch from the connection unit 152 through a predetermined logic calculation program, and arranges the resistance of each branch, so that the I2C port of the output unit 154 transmits it to the display screen 131, and the display screen 131 displays the resistance values ​​of multiple branches; the logic processing unit 153 also compares the resistance data of each branch, and outputs the resistance value of the branch unit with the smallest resistance to the speaker 132 through the IO port of the output unit 154, and the speaker 132 plays the branch with the smallest resistance, so as to help the user determine the location of the cable core being calibrated at this time.

[0082] like Figure 2 and Figure 3 As shown, in the embodiment of the present application, the controller 15 further includes:

[0083] The storage unit 155 is connected to the connection unit 152 to store the digital signals of multiple branches received by the connection unit 152, and receive and store the branch information of the minimum resistance value processed by the logic processing unit 153 through the connection unit 152.

[0084] In this embodiment, the storage unit 155 is connected to the connection unit 152, so that it can be used to receive and store signals transmitted through the connection unit 152, including digital signals of multiple branch resistance values ​​and branch information of the minimum resistance value, for system access calculation use.

[0085] like Figure 2 and Figure 3 As shown, in the embodiment of the present application, the controller 15 further includes:

[0086] a system control unit 156, wherein the system control unit 156 is connected to the connection unit 152 to receive a digital signal transmitted by the connection unit 152;

[0087] The external transmission unit 157 is connected to the system control unit 156, and is used to receive the digital signal and transmit the digital signal to the outside.

[0088] In this embodiment, the controller 15 includes a system control unit 156, a connection unit 152 and an external transmission unit 157. The connection unit 152 is connected to the system control unit 156, so that the system control unit 156 can receive digital signals from the connection unit 152. The system control unit is the STM32 core board ARM core, which is the "brain" of the core board and participates in system control, logical calculation and other functions, so that digital signals can be logically processed. The system control unit 156 is also connected to the external transmission unit 157, so that the digital signal processed by the system control unit 156 can be connected to the core board through the CAN communication protocol to realize information interaction with the outside world.

[0089] In this embodiment, the controller 15 further includes a reset unit 158 ​​, which is connected to the connection unit 152 , so as to realize a reset function.

[0090] like Figure 1 As shown, in the embodiment of the present application, it also includes:

[0091] The switch component 16 is connected to the controller 15 to control the controller 15 to be turned on or off.

[0092] In this embodiment, when the switch assembly 16 is opened, the secondary calibration device 1 of the current transformer can calibrate the terminal 22 of the current transformer 2, while when the switch assembly 16 is closed, the secondary calibration device 1 of the current transformer is in a closed state and cannot calibrate the terminal 22 of the current transformer 2.

[0093] like Figure 5As shown, in a second aspect, the present application also provides a secondary calibration method for a current transformer, comprising:

[0094] S101, connecting multiple terminals of a current transformer junction box to multiple current terminal blocks of an electric control cabinet in sequence;

[0095] The plurality of terminals of the current transformer junction box are electrically connected to the plurality of current terminal blocks of the electric control cabinet.

[0096] S102, connecting a plurality of resistance measurement interfaces of the secondary calibration device of the current transformer to a plurality of current terminal block test interfaces of the electric control cabinet in a one-to-one correspondence;

[0097] S103, connecting the common end of the measuring line of the secondary calibration device of the current transformer to the equipotential ground bar of the electric control cabinet;

[0098] S104, connecting the plurality of terminals of the current transformer junction box to the equipotential ground bar of the electric control cabinet in sequence, so as to calibrate the plurality of terminals in sequence.

[0099] In this embodiment, the current transformer usually has multiple secondary windings with different transformation ratios, which are used by secondary equipment such as protection, measurement, and metering through the secondary cable loop. Usually, in conventional substations and smart substations with a voltage level of 110 kV and above, conventional sampling of currents of different groups adopts the form of phase-split wiring, that is, the three phases A / B / C of the same group are respectively connected to the current terminal block of the control cabinet. The current transformer includes a secondary winding junction box, in which a plurality of secondary wire terminals are arranged. The secondary wire terminals are fixed to the secondary cable core by bolts or screws, and the terminals are connected to the control cabinet through the secondary cable.

[0100] In this embodiment, the control cabinet includes a current terminal block, a terminal block movable slider part, a terminal block static part and a terminal block test interface. The current terminal block is used to connect to the terminal posts of the three-phase current transformer body terminal box through secondary cables from top to bottom; the movable slider part of the terminal block can be slid left and right by twisting with a flat-blade screwdriver to realize the left and right switching of the terminal block; when the movable slider part of the terminal block slides to the right and is tightened, the terminal block is turned on left and right, and when the movable slider part of the terminal block slides to the left, the terminal block is disconnected left and right to achieve isolation; the terminal block test interface is for the test line to be connected to it.

[0101] In this embodiment, the current transformer is arranged at one place, and the secondary calibration device of the control cabinet and the current transformer is arranged at another place. The A debugging personnel is located at the location of the current transformer, and the B debugging personnel is located at the location of the control cabinet and the secondary calibration device of the current transformer. The debugging personnel confirm that the interval where they are located is in a non-operating state, and after measuring and testing the electricity, the interval is not energized. The A debugging personnel connects the multiple secondary terminals of the current transformer junction box to the multiple current terminal blocks from top to bottom of the control cabinet one by one through a multi-core secondary cable. The A debugging personnel holds a single-core metal wire with exposed insulation at both ends, one end of which is connected to the equipotential grounding bar, and the other end is waiting to be short-circuited with the metal columns of each winding in the junction box of the current transformer. The B debugging personnel uses a screwdriver to slide open the movable slider of the A / B / C three-phase current terminal block part at the control cabinet in turn, including sliding open the grounding wires of each winding. Then, the B commissioning personnel connected the common end of the measurement line of the secondary calibration device of the current transformer to the equipotential ground bar of the electric control cabinet, and used the test board line to connect multiple resistance measurement interfaces to the current terminal block test interface one by one. At this time, the result display component shows that the resistance value of each branch is OL, and OL means that the resistance value is infinite. At this time, the status of the secondary calibration device of the electric control cabinet and the current transformer is normal. The commissioning personnel can start to calibrate the current transformer.

[0102] In this embodiment, the specific connection form in which multiple resistance measurement interfaces are connected to the current terminal block test interface in a one-to-one correspondence is: K11 in the resistance measurement interface of the secondary calibration device of the current transformer is connected to A1S1 at the current terminal block test interface number 1 of the electric control cabinet, K12 in the resistance measurement interface of the secondary calibration device of the current transformer is connected to A1S2 at the current terminal block test interface number 5 of the electric control cabinet, K13 in the resistance measurement interface of the secondary calibration device of the current transformer is connected to A1S3 at the current terminal block test interface number 9 of the electric control cabinet, K21 in the resistance measurement interface of the secondary calibration device of the current transformer is connected to A2S1 at the current terminal block test interface number 13 of the electric control cabinet, K22 is connected to A2S2 at the current terminal sequence number 17, K23 is connected to A2S3 at the current terminal sequence number 21, and the same applies to other windings.

[0103] In this embodiment, when calibrating the line through the secondary calibration device of the current transformer, the A debugging personnel connects the metal wire connected to the equipotential ground bar at one end to the A1S1 terminal at the current transformer body terminal box, and the B debugging personnel checks the resistance of each branch displayed on the result display component of the secondary calibration device of the current transformer. If the resistance of each branch is consistent with the terminal short-circuited by the A debugging personnel, the resistance of K11 is the smallest at this time, and the resistance of other branches is greater than the resistance of K11. At this time, it can be confirmed that the wire core connected to the A1S1 terminal is short-circuited to the ground by the A debugging personnel. The A debugging personnel removes the short-circuit wire at the A1S1 terminal, and the resistance of each branch resumes to display OL. After that, the A debugging personnel connects the metal wire connected to the equipotential ground bar at one end to the A1S2 terminal at the current transformer body terminal box. At this time, the B debugging personnel observes the resistance of each branch displayed on the result display component. At this time, the K12 resistance is the smallest, and the resistance of other branches is greater than the resistance of K12. At this point, it can be confirmed that the wire connected to the A1S2 terminal is short-circuited to the ground by the A debugger, and the same applies to other wires.

[0104] Therefore, the secondary calibration device of the current transformer provided in the present application only needs to connect the terminal to be calibrated in the current transformer terminal box to the equipotential ground bar of the electric control cabinet when calibrating the terminal posts of the current transformer. The calibration method is simple and convenient, easy to operate, and there is no need to disassemble the winding core of the current transformer terminal box, thereby effectively reducing the risks of terminal damage, wire core restoration errors, and secondary circuit open caused by disassembling the secondary wire at the current transformer terminal box, significantly improving the efficiency and quality of on-site debugging, avoiding the secondary monitoring and protection devices from failing to correctly reflect the actual operation of the primary equipment, causing the circuit breaker protection device to refuse to operate or malfunction, leaving safety hazards for the smooth commissioning of the substation, reducing safety hazards, and allowing the power grid to operate safely and stably.

[0105] like Figure 6 As shown, the present application also provides another secondary calibration method for a current transformer, comprising:

[0106] S201, checking the tightness of multiple terminals of the current transformer junction box;

[0107] S202, connecting a plurality of terminal blocks of a current transformer junction box to a plurality of current terminal blocks of an electric control cabinet in sequence;

[0108] S203, electrically connecting a plurality of terminal blocks of a current transformer junction box to a plurality of current terminal blocks of an electric control cabinet;

[0109] S204, connecting the multiple resistance measurement interfaces of the secondary calibration device of the current transformer to the multiple current terminal block test interfaces of the electric control cabinet in a one-to-one correspondence;

[0110] S205, connecting the common end of the measuring line of the secondary calibration device of the current transformer to the equipotential ground bar of the electric control cabinet;

[0111] S206, connecting the plurality of terminals of the current transformer junction box to the equipotential ground bar of the electric control cabinet in sequence, so as to calibrate the plurality of terminals in sequence.

[0112] In this embodiment, the A debugging personnel opens the junction box of the current transformer with a wrench at the current transformer, checks the tightness of the wiring of each terminal, and then connects the multiple secondary terminals of the current transformer junction box to the multiple current terminal blocks from top to bottom of the control cabinet through a multi-core secondary cable. The A debugging personnel holds a single-core metal wire with exposed insulation at both ends, one end is connected to the equipotential ground bar, and the other end is waiting to be short-circuited with the metal columns of each winding in the junction box of the current transformer. The B debugging personnel uses a screwdriver to cut open the movable slider of the A / B / C three-phase current terminal block part at the control cabinet in turn, including the grounding wires of each winding. Then the B debugging personnel connects the common end of the measurement line of the secondary calibration device of the current transformer to the equipotential ground bar of the electric control cabinet, and uses the test board line to connect multiple resistance measurement interfaces to the current terminal block test interface one by one. At this time, the result display component shows that the resistance value of each branch is OL, and OL means that the resistance value is infinite. At this time, the status of the secondary calibration devices of the electric control cabinet and the current transformer are normal. The commissioning personnel can start to calibrate the current transformer. The specific connection form of the multiple resistance measurement interfaces and the current terminal block test interfaces corresponding to each other is: K11 in the resistance measurement interface of the secondary calibration device of the current transformer is connected to A1S1 at the serial number 1 of the current terminal block test interface of the electric control cabinet, K12 in the resistance measurement interface of the secondary calibration device of the current transformer is connected to A1S2 at the serial number 5 of the current terminal block test interface of the electric control cabinet, K13 in the resistance measurement interface of the secondary calibration device of the current transformer is connected to A1S3 at the serial number 9 of the current terminal block test interface of the electric control cabinet, K21 in the resistance measurement interface of the secondary calibration device of the current transformer is connected to A2S1 at the serial number 13 of the current terminal block test interface of the electric control cabinet, K22 is connected to A2S2 at the serial number 17 of the current terminal, K23 is connected to A2S3 at the serial number 21 of the current terminal, and the other windings are connected by analogy.

[0113] Therefore, the present application provides a secondary calibration method for a current transformer. When calibrating the terminal posts of the current transformer, it is only necessary to connect the terminal posts corresponding to the ones to be calibrated in the terminal box of the current transformer to the equipotential ground bar of the electric control cabinet. The calibration method is simple and convenient, easy to operate, and there is no need to disassemble the winding core of the current transformer terminal box. Therefore, the risks of terminal damage, core restoration errors, and secondary circuit open caused by disassembling the secondary wires at the terminal box of the current transformer can be effectively reduced, and the efficiency and quality of on-site debugging can be significantly improved, which avoids the secondary monitoring and protection devices from failing to correctly reflect the actual operation of the primary equipment, causing the circuit breaker protection device to refuse to operate or malfunction, leaving safety hazards for the smooth commissioning of the substation, reducing safety hazards, and allowing the power grid to operate safely and stably.

[0114] So far, various embodiments of the present application have been described in detail. In order to avoid obscuring the concept of the present application, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed herein.

[0115] Although some specific embodiments of the present application have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present application. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict.

Claims

1. A secondary calibration device for a current transformer, characterized in that: include: A plurality of resistance measurement interfaces, the plurality of resistance measurement interfaces are used to be connected one-to-one with a plurality of current terminal block test interfaces of the electric control cabinet, so as to measure the resistance values ​​of the branches corresponding to the plurality of current terminal block test interfaces; A common end of the measuring line, which is used to connect to the equipotential ground bar of the electric control cabinet to connect the secondary calibration device of the current transformer to the electric control cabinet; A result display component is connected to a plurality of resistance measurement interfaces respectively, and is used to receive and display resistance values ​​of branches corresponding to a plurality of current terminal block test interfaces.

2. The secondary calibration device of the current transformer according to claim 1, characterized in that: Also includes: A housing, the outer surface of which is provided with a plurality of the resistance measurement interfaces, the common end of the measurement lines and a result display component; A controller is disposed in the shell, and is connected to the plurality of resistance measurement interfaces and the result display component to receive resistance values ​​of the plurality of branches transmitted by the plurality of resistance measurement interfaces, convert the resistance values ​​of the plurality of branches and transmit them to the result display component for display.

3. The secondary calibration device of the current transformer according to claim 2, characterized in that: The result display component includes: A display screen, the display screen is arranged on the outer surface of the housing, the display screen is connected to the controller to receive and display the resistance values ​​of the multiple branches converted by the controller; and A speaker is arranged on the outer surface of the shell and is connected to the controller to receive and broadcast the branch with the smallest resistance value among multiple branches.

4. The secondary calibration device of the current transformer according to claim 2, characterized in that: The result display component also includes: Multiple warning lights are arranged on the outer surface of the shell, and the multiple warning lights are arranged in a one-to-one correspondence with the multiple resistance measurement interfaces. The warning lights are connected to the controller, and the controller is used to control the brightness of the corresponding warning lights according to the resistance value.

5. The secondary calibration device of the current transformer according to claim 3, characterized in that: The controller comprises: A conversion unit, the conversion unit being connected to the resistance measurement interface and configured to receive resistance values ​​of a plurality of branches and convert the resistance values ​​into digital signals; A connecting unit, the connecting unit is connected to the converting unit and is used to receive the digital signal transmitted by the converting unit; A logic processing unit, connected to the connection unit, for processing and comparing the plurality of digital signals to obtain a branch corresponding to a minimum resistance value; An output unit is connected to the logic processing unit, and the output unit is connected to the display screen and the speaker to send the resistances of the multiple branches to the display screen for display, and transmit the branch with the smallest resistance value to the speaker for playback.

6. The secondary calibration device of the current transformer according to claim 5, characterized in that: The controller further comprises: A storage unit is connected to the connection unit to store digital signals of multiple branches received by the connection unit, and to receive and store branch information of the minimum resistance value processed by the logic processing unit through the connection unit.

7. The secondary calibration device of the current transformer according to claim 4, characterized in that: The controller further comprises: A system control unit, the system control unit is connected to the connection unit to receive the digital signal transmitted by the connection unit; An external transmission unit, the external transmission unit is connected to the system control unit, and is used to receive the digital signal and transmit the digital signal to the outside world.

8. The secondary calibration device of the current transformer according to claim 3, characterized in that: Also includes: A switch component is connected to the controller to control the controller to be turned on or off.

9. A secondary calibration method for a current transformer, characterized in that: Connect multiple terminals of the current transformer junction box to multiple current terminal blocks of the electric control cabinet in sequence; Connecting the multiple resistance measurement interfaces of the secondary calibration device of the current transformer to the multiple current terminal block test interfaces of the electric control cabinet one by one; Connecting the common end of the measuring line of the secondary calibration device of the current transformer to the equipotential ground bar of the electric control cabinet; Connect multiple terminals of the current transformer junction box to the equipotential ground bar of the electric control cabinet in sequence, so as to calibrate the multiple terminals in sequence.

10. The secondary calibration method of a current transformer according to claim 9, characterized in that: Before the multiple terminals of the current transformer junction box are sequentially connected to the multiple current terminal blocks of the electric control cabinet, the method includes: checking the tightness of the multiple terminals of the current transformer junction box.

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