Universal current transformation ratio adjusting system and method

Abstract

The invention belongs to the field of power systems, and discloses a universal current transformation ratio adjusting system and method.A pre-adjusting current transformation ratio measuring range is obtained and transmitted through a first collecting unit, a secondary signal of a mutual inductor is obtained and transmitted through a second collecting unit, and a PLC controls a current transformation truth table according to the pre-adjusting current transformation ratio measuring range and the pre-stored current transformation truth table. PLC coding values can be intelligently obtained, current gears are switched according to the PLC coding values, and automatic adjustment of the measuring range is achieved; after the current gear is switched, the PLC can also accurately calculate and output a corresponding rear end voltage value according to a secondary signal of the mutual inductor, a pre-adjusting current transformation ratio measuring range and a current transformation truth table; and finally, the power current module converts the rear-end voltage value into a current value and transmits the current value to the current metering equipment, so that the metering accuracy and the universality of the system are improved. The system effectively solves the problem of multiplying power error caused by non-uniform measuring ranges, realizes automatic switching of the current transformation ratio, and is convenient for electric energy metering.

Description

Technical Field

[0001] The present invention belongs to the technical field of power transmission and distribution of electric power systems, and in particular relates to a universal current transformation ratio adjustment system and method. Background Art

[0002] During the operation of the power system, it is crucial to ensure the reliability of power supply in order to cope with sudden power outages or power outages caused by planned maintenance. For this purpose, a 300kW / 400kW, 0.4kV emergency power supply vehicle is usually used for emergency power supply. When the emergency power supply vehicle arrives at the site where power supply needs to be guaranteed, the staff will take a series of operations to connect the power generation vehicle with the user's distribution system, including pulling open the low-voltage outgoing line circuit breaker and the high-voltage incoming line load switch in the user-side box-type substation to disconnect the distribution transformer from the low-voltage busbar, and then directly connect the power generation vehicle's cables (L1, L2, L3) and the neutral cable to the low-voltage busbar (U, V, W, N); during the above operation, the secondary terminals of the current transformer must be reliably connected to the phase ammeters at the front end of the circuit breaker to measure the electric energy.

[0003] However, in actual applications, the measuring ranges of pointer ammeters or electric energy meters equipped in different user-side access devices are often different. Due to the inconsistency of the measuring ranges, there may be a multiplier error between the value displayed on the user-side ammeter and the actual current value of each phase, affecting the accuracy of the measurement.

[0004] It can be seen that the existing current transformers and ammeters have fixed ranges and poor versatility. Due to the non-uniform ranges, there is a multiplication error between the value displayed on the user-side ammeter and the actual current value of each phase. Summary of the invention

[0005] The present invention provides a universal current transformation ratio adjustment system and method to solve the technical problem that the existing current transformers and ammeters have fixed ranges, poor universality, and a multiplier error exists between the value displayed on the user-side ammeter and the actual current value of each phase due to the non-uniform range. By adopting the system and method, the current ratio can be changed according to actual needs, and various types of ammeters can be matched to meet the measurement needs.

[0006] In order to achieve the above object, the present invention adopts the following technical contents: In a first aspect, the present invention provides a universal current transformation ratio adjustment system, comprising: A first acquisition unit, used for acquiring and transmitting a pre-adjusted current transformation ratio range; A second acquisition unit, used for acquiring and transmitting a secondary signal of a mutual inductor; A PLC controller, for obtaining a PLC code value according to a received pre-adjusted current transformation ratio range and a pre-stored current transformation truth table, and switching the current gear according to the PLC code value; and after the current gear is switched, calculating and outputting a corresponding rear-end voltage value according to the received transformer secondary signal, the pre-adjusted current transformation ratio range and the pre-stored current transformation truth table; The power current module is used to convert the received back-end voltage value into a current value and transmit the current value to the current metering device.

[0007] Furthermore, the first acquisition unit includes a touch screen, which is electrically connected to the PLC controller; the touch screen is used to acquire the pre-adjusted current ratio range set by the user, and transmit the acquired pre-adjusted current ratio range to the PLC controller.

[0008] Furthermore, the second acquisition unit is connected between the secondary output terminal of the transformer and the PLC controller; the maximum current of the secondary signal of the transformer is 120 mA.

[0009] Furthermore, the second acquisition unit includes a signal separation circuit and a voltage amplification circuit connected between the secondary output end of the transformer and the PLC controller; the signal separation circuit is used to condition the received transformer secondary signal and output a stable current signal; the voltage amplification circuit converts the received stable current signal into a voltage signal.

[0010] Furthermore, the voltage amplifier circuit is connected to an AD conversion circuit for performing AD conversion on the voltage signal output by the voltage amplifier circuit and transmitting the converted voltage signal to the PLC controller.

[0011] Furthermore, the current gear includes 16 gears, namely: 50:5, 100:5, 15:5, 200:5, 300:5, 400:5, 500:5, 600:5, 700:5, 800:5, 900:5, 1000:5, 1200:5, 1500:5, a first spare gear and a second spare gear.

[0012] Furthermore, the PLC code values ​​corresponding to the 16 current gears are 00001, 00010, 00011, 00100, 00101, 00110, 00111, 01000, 01001, 01010, 01011, 01100, 01101, 01110, 01111 and 10000 respectively.

[0013] In a second aspect, the present invention provides a current ratio adjustment method, based on the above-mentioned general current ratio adjustment system, comprising: The first acquisition unit acquires and transmits the pre-adjusted current transformation ratio range; The second acquisition unit acquires and transmits the secondary signal of the mutual inductor; The PLC controller obtains a PLC code value according to the received pre-adjusted current transformation ratio range and a pre-stored current transformation truth table, and switches the current gear according to the PLC code value; After the current gear is switched, the PLC controller calculates and outputs the corresponding rear-end voltage value according to the received transformer secondary signal, the pre-adjusted current transformation ratio range and the pre-stored current transformation truth table; The power current module converts the received back-end voltage value into a current value and transmits the current value to the current measuring device.

[0014] Furthermore, the pre-adjusted current transformation ratio range is obtained through interaction between the user and the touch screen.

[0015] Furthermore, the universal current transformation ratio adjustment system is connected to the secondary side circuit of the current transformer.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a universal current ratio regulation system, which obtains and transmits a pre-adjusted current ratio range through a first acquisition unit, obtains and transmits a transformer secondary signal through a second acquisition unit, and a PLC controller can intelligently obtain a PLC code value according to the received pre-adjusted current ratio range and a pre-stored current conversion truth table, and switch the current gear according to the PLC code value, thereby realizing automatic matching and adjustment of the range; after the current gear is switched, the PLC controller can also accurately calculate and output the corresponding rear-end voltage value according to the transformer secondary signal, the pre-adjusted current ratio range and the current conversion truth table; finally, the power current module converts this rear-end voltage value into a current value and transmits it to the current metering device, thereby greatly improving the accuracy of the measurement and the versatility of the system; the use of this system effectively solves the problem of multiplier error caused by inconsistent ranges, realizes automatic switching of the current ratio, and facilitates electric energy measurement. At the same time, the universal design of the system enables it to be widely used in various current measurement scenarios, reducing the cost of equipment replacement and calibration.

[0017] Preferably, in the present invention, the introduction of the touch screen allows the user to intuitively set the pre-adjusted current transformation ratio range, thereby improving the convenience and user-friendliness of the operation; at the same time, the electrical connection between the touch screen and the PLC controller ensures the accurate transmission of the set value, thereby improving the response speed of the system.

[0018] Preferably, in the present invention, by directly connecting to the secondary output terminal of the transformer, the second acquisition unit can accurately obtain the secondary signal of the transformer, providing a reliable data basis for subsequent calculation and processing; at the same time, this design also simplifies the structure of the system and improves the stability of the system.

[0019] Preferably, in the present invention, the signal conditioning circuit can condition the received transformer secondary signal and output a stable current signal, thereby improving the signal's anti-interference capability; the voltage amplification circuit converts the stable current signal into a voltage signal, thereby facilitating subsequent processing and analysis; this design improves the system's processing capability for the transformer secondary signal.

[0020] Preferably, in the present invention, the AD conversion circuit can digitally convert the voltage signal output by the voltage amplifier circuit, so as to facilitate the subsequent calculation and processing by the PLC controller; this design improves the system's digital processing capability for analog signals and further enhances the intelligence level of the system.

[0021] Preferably, in the present invention, a variety of current gear selections are provided, so that the system can flexibly adapt to current measurement requirements of different ranges; at the same time, the rich gear selections also improve the system's sensitivity and accuracy to current changes.

[0022] Preferably, in the present invention, a unique PLC code value is allocated to each current gear, thereby achieving accurate switching and control of the current gear; this design improves the reliability and stability of the system and ensures the accuracy of current measurement.

[0023] The present invention also provides a current ratio adjustment method based on the above-mentioned general current ratio adjustment system; the method realizes precise control of current measurement by intelligently adjusting the current ratio; the method has the advantages of simple operation, accurate measurement, strong adaptability, etc., and can be widely used in various current measurement scenarios.

[0024] Preferably, in the present invention, the pre-adjusted current transformation ratio range can be conveniently set through interaction between the user and the touch screen, thereby improving the convenience and user-friendliness of operation; at the same time, this design also reduces the risk of human operating errors and improves the reliability of the system.

[0025] Preferably, in the present invention, the system is connected to the secondary side circuit of the current transformer, so that the current signal output by the transformer can be directly obtained, thereby improving the measurement accuracy and response speed of the system; at the same time, this design also simplifies the installation and debugging process of the system and reduces the deployment cost of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic structural diagram of a general current transformation ratio adjustment system provided in an embodiment of the present invention; Figure 2 A working principle block diagram of a general current ratio regulation system provided by an embodiment of the present invention; Figure 3A circuit structure schematic diagram of a universal current transformation ratio adjustment system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail in the following specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0031] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does 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 the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0032] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] Example 1 As mentioned in the background technology, when the emergency power supply vehicle arrives at the site where power supply needs to be guaranteed, the staff will take a series of operations to connect the power generation vehicle with the user's distribution system, including pulling open the low-voltage outgoing line circuit breaker and the high-voltage incoming line load switch in the user-side box-type substation to disconnect the distribution transformer from the low-voltage busbar, and then directly connect the power cables (L1, L2, L3) and the neutral cable of the power generation vehicle to the low-voltage busbar (U, V, W, N); during the above operation process, the secondary terminals of the current transformer need to be reliably connected to the phase ammeters at the front end of the circuit breaker to measure the electric energy; however, in actual applications, the ranges of the pointer ammeters or electric energy meters equipped in different user-side access devices often differ; due to the inconsistency of the ranges, there may be a multiplier error between the value displayed on the user-side ammeter and the actual current value of each phase, affecting the accuracy of the measurement. That is to say, the current technology only has a corresponding single current transformer or electric energy meter, that is, a current transformer can only correspond to one output, and the range is fixed. For example, a 100A current transformer can only correspond to one fixed 0-5A secondary port, and different electric energy meters can only support one range; therefore, due to the poor versatility of current transformers and ammeters, in actual applications, good range matching cannot be achieved, resulting in errors in the final measurement results and difficulty in ensuring accuracy.

[0035] In order to solve the above problems, the present embodiment provides a universal current ratio adjustment system and method, which connects the system between the current transformer and the current metering device; can match current metering devices of various types and ranges through range setting; the current metering device adopts an ammeter or an electric energy meter; realizes the free switching of the current ratio, and can be applied to various occasions requiring the current ratio, so that the power generation vehicle can be freely connected to various types of electric meters in one place, which is convenient for electric energy measurement.

[0036] The present invention is further described in detail below with reference to the accompanying drawings and embodiments: like Figure 1As shown, this embodiment provides a universal current ratio adjustment system, which aims to solve the problems of range mismatch and insufficient precision in current measurement. The system integrates multiple key components to work together to achieve accurate current measurement and adjustment, including: Information collection module, including: Pre-adjusted range acquisition unit (first acquisition unit): This acquisition unit is responsible for capturing the pre-adjusted current ratio range set by the user to ensure that the system can accurately adapt to different current measurement requirements.

[0037] Transformer signal acquisition unit (second acquisition unit): connected to the secondary output terminal of the transformer, this acquisition unit is responsible for receiving the secondary signal output by the transformer, and the maximum current limit of the signal is 120mA. In order to improve the stability and reliability of the signal, the unit also has built-in signal conditioning and voltage amplification circuits, as well as AD conversion circuits to ensure that the signal can be accurately and losslessly transmitted to the control system.

[0038] Intelligent control core, including: PLC controller: As the brain of the system, the PLC controller calculates the appropriate PLC code value based on the received pre-adjusted range and transformer signal, combined with the pre-stored current conversion truth table, and switches the current gear accordingly; after the gear switching is completed, the PLC controller will use this information again to calculate the corresponding back-end voltage value and output it to the next-level processing unit, namely the current output module.

[0039] Current output module, including: Power current module: This module is responsible for converting the back-end voltage value output by the PLC controller into a current value, and then transmitting it to the current metering device for further processing or display; among them, the current metering device uses an ammeter or an electric energy meter.

[0040] The system obtains and transmits the pre-adjusted current ratio range through the first acquisition unit, obtains and transmits the transformer secondary signal through the second acquisition unit, and the PLC controller can intelligently obtain the PLC code value according to the received pre-adjusted current ratio range and the pre-stored current conversion truth table, and switch the current gear according to the PLC code value, thereby realizing automatic matching and adjustment of the range; after the current gear is switched, the PLC controller can also accurately calculate and output the corresponding rear-end voltage value according to the transformer secondary signal, the pre-adjusted current ratio range and the current conversion truth table; finally, the power current module converts this rear-end voltage value into a current value and transmits it to the current metering equipment, thereby greatly improving the accuracy of the measurement and the versatility of the system; the use of this system effectively solves the problem of multiplication error caused by inconsistent ranges, realizes automatic switching of the current ratio, and facilitates electric energy metering.

[0041] The present embodiment provides a universal current ratio adjustment system with flexible gear selection: in the present system, up to 16 current gears are provided, including the commonly used 50:5, 100:5, etc., specifically 50:5, 100:5, 15:5, 200:5, 300:5, 400:5, 500:5, 600:5, 700:5, 800:5, 900:5, 1000:5, 1200:5, 1500:5, the first spare gear and the second spare gear to meet the current measurement requirements in different scenarios.

[0042] PLC coding: Each gear corresponds to a unique PLC coding value, which are 00001, 00010, 00011, 00100, 00101, 00110, 00111, 01000, 01001, 01010, 01011, 01100, 01101, 01110, 01111 and 10000, ensuring the accuracy and reliability of gear switching.

[0043] In this system, a variety of current range options are provided, allowing the system to flexibly adapt to current measurement requirements of different ranges; the rich range selection also improves the system's sensitivity and accuracy to current changes; and a unique PLC coding value is assigned to each current range to achieve precise switching and control of the current range; this design improves the reliability and stability of the system and ensures the accuracy of current measurement.

[0044] In this embodiment, the second acquisition unit preferably uses a touch screen, and the touch screen interacts with the PLC controller; the touch screen is used to collect the pre-adjusted current ratio range set by the user, and transmit the collected pre-adjusted current ratio range to the PLC controller; the introduction of the touch screen allows the user to intuitively set the pre-adjusted current ratio range, which improves the convenience and user-friendliness of operation; at the same time, the electrical connection between the touch screen and the PLC controller ensures the accurate transmission of the set value and improves the response speed of the system. Through the interaction between the user and the touch screen, the pre-adjusted current ratio range can be conveniently set, which improves the convenience and user-friendliness of operation; at the same time, this design also reduces the risk of human operating errors and improves the reliability of the system.

[0045] This embodiment provides a universal current ratio adjustment system, and the specific working principle is as follows: The system is equipped with a 600A current transformer signal. The transformer secondary signal: 0-120mA. The microcomputer uses an amplifier circuit to convert it into a voltage signal. The microcomputer system collects 0-1V voltage signals through AD. After the microcomputer collects the voltage signal, the PLC program communicates with the touch screen. The PLC receives the current ratio range. After receiving the current gear range, the microcomputer system calculates according to the current conversion truth table shown in Table 1, calculates the matching value of the current range of each channel, and outputs Figure 3 The back-end voltage on the truth table controls the power current module and outputs the corresponding current value. The output current value will be connected to the corresponding electric energy meter to measure the electric energy. After the PLC receives the range, it converts the PLC code of the current conversion truth table shown in Table 1 and outputs the corresponding level signal. After the microcomputer receives the corresponding level signal, it will automatically switch to the set current gear for the user to use. This system can set various types of current ratios at will, and can replace various types of power frequency current transformers. By using digital technology, various universal electric energy meters can be set at will; it makes up for the problem that the existing transformer has only one ratio, and improves the versatility of the entire metering system.

[0046] Table 1 is the current meter conversion truth table

[0047] In Table 1, the transformation ratio of the front-end transformer is: 1000:0.2, that is, 5000:1; the maximum current of the generator is 600A; the maximum output current of the transformer is 120mA.

[0048] Example 2 This embodiment provides a general current ratio adjustment system, such as Figure 2 As shown, Figure 2 The working principle block diagram of the current ratio regulation system is shown in the figure. Among them, phase A, phase B, phase C, phase N and ground represent the connection and connection of the power generation vehicle. Phase A and phase N are the power supply of the current ratio regulation system, which are equipped with leakage protection, emergency stop and power switch. Then the switching power supply is connected. The specification of the switching power supply is that the input voltage is 220V and the output is 24V / 10A or 24V / 1.5A. Then the PLC, microcomputer processor and power current module are powered respectively. Then the PLC obtains the corresponding PLC code value according to the received current ratio range and the preset current conversion truth table, and switches to the corresponding setting channel (current gear) according to the PLC code value. The secondary signal of the transformer is collected through the microcomputer processor, and the microcomputer processor converts it into a voltage signal using an amplification circuit. Through the corresponding channel, the current is amplified to the required current, the matching value of the current range of each channel is calculated, the back-end voltage on the output current conversion truth table is output, and the power current module is controlled to output the corresponding current value. The output current value will be connected to the corresponding electric energy meter for use by the electric energy meter.

[0049] like Figure 3 As shown, Figure 3 This is a circuit schematic diagram of each component in a general current ratio regulation system, specifically: Figure 3Part A is the secondary signal access port of the primary-side current transformer; Part B is the amplifying circuit structure, which is responsible for converting the tiny current signal into a voltage signal and then amplifying it after the secondary signal is connected; Part C is the PLC signal encoder, which is responsible for encoding according to the PLC code value and transmitting the PLC code value to Part D - the microcomputer processor; Part E - the switching current circuit structure is controlled according to the microcomputer processor control program, and the current ratio channel is selected by switching the current circuit; Among them, F is the power filter circuit; G is the power indicator light; H is the wiring terminal.

[0050] In summary, the present invention provides a universal current transformation ratio adjustment system and method, which has the following advantages over existing testing measures: This universal current ratio regulation system can accurately obtain the pre-adjusted current ratio range and the secondary signal of the transformer by integrating the first acquisition unit and the second acquisition unit, providing a reliable data basis for subsequent processing; secondly, the use of the PLC controller enables the system to automatically calculate the PLC code value and switch the current gear according to the received information, which not only improves the accuracy of current regulation, but also realizes intelligent control and reduces the tediousness of manual operation. Furthermore, through the pre-stored current conversion truth table, the PLC controller can further calculate and output the corresponding back-end voltage value. This design enhances the flexibility and adaptability of the system; in addition, the power current module converts the back-end voltage value into a current value and transmits it to the current metering device, ensuring the accurate transmission and measurement of current data. It is worth noting that this system also supports users to set the pre-adjusted current ratio range through the touch screen, providing a good human-computer interaction experience; at the same time, the system is connected to the secondary side circuit of the current transformer, which can directly monitor and adjust the current, ensuring the stable operation of the power system. It can be seen that the universal current ratio regulation system provided by the present invention effectively solves the problem of rate error caused by inconsistent measuring ranges, realizes automatic switching of current ratio, has a high level of automation and intelligence in current ratio regulation, and can effectively improve the operating efficiency and safety of the power system.

[0051] The above embodiment is only one of the implementation methods that can realize the technical solution of the present invention. The scope of protection claimed by the present invention is not limited only to this embodiment, but also includes changes, replacements and other implementation methods that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention.

Claims

1. A universal current ratio regulation system, characterized in that: include: A first acquisition unit, used for acquiring and transmitting a pre-adjusted current transformation ratio range; A second acquisition unit, used for acquiring and transmitting a secondary signal of a mutual inductor; A PLC controller, for obtaining a PLC code value according to a received pre-adjusted current transformation ratio range and a pre-stored current transformation truth table, and switching the current gear according to the PLC code value; and after the current gear is switched, calculating and outputting a corresponding rear-end voltage value according to the received transformer secondary signal, the pre-adjusted current transformation ratio range and the pre-stored current transformation truth table; The power current module is used to convert the received back-end voltage value into a current value and transmit the current value to the current metering device.

2. The universal current transformation ratio adjustment system according to claim 1, characterized in that: The first acquisition unit includes a touch screen, which is electrically connected to the PLC controller; the touch screen is used to acquire the pre-adjusted current transformation ratio range set by the user, and transmit the acquired pre-adjusted current transformation ratio range to the PLC controller.

3. The universal current transformation ratio regulation system according to claim 1, characterized in that: The second acquisition unit is connected between the secondary output terminal of the transformer and the PLC controller; the maximum current of the secondary signal of the transformer is 120 mA.

4. The universal current transformation ratio adjustment system according to claim 3, characterized in that: The second acquisition unit includes a signal separation circuit and a voltage amplification circuit connected between the secondary output end of the transformer and the PLC controller; the signal separation circuit is used to condition the received transformer secondary signal and output a stable current signal; the voltage amplification circuit converts the received stable current signal into a voltage signal.

5. The universal current transformation ratio adjustment system according to claim 4, characterized in that: The voltage amplifier circuit is connected to an AD conversion circuit for performing AD conversion on the voltage signal output by the voltage amplifier circuit and transmitting the converted voltage signal to the PLC controller.

6. The universal current transformation ratio adjustment system according to claim 1, characterized in that: The current gear includes 16 gears, namely: 50:5, 100:5, 15:5, 200:5, 300:5, 400:5, 500:5, 600:5, 700:5, 800:5, 900:5, 1000:5, 1200:5, 1500:5, a first spare gear and a second spare gear.

7. The universal current transformation ratio adjustment system according to claim 6, characterized in that: The PLC code values ​​corresponding to the 16 current gears are 00001, 00010, 00011, 00100, 00101, 00110, 00111, 01000, 01001, 01010, 01011, 01100, 01101, 01110, 01111 and 10000 respectively.

8. A current transformation ratio adjustment method, characterized in that: The universal current ratio adjustment system according to any one of claims 1 to 7 comprises: The first acquisition unit acquires and transmits the pre-adjusted current transformation ratio range; The second acquisition unit acquires and transmits the secondary signal of the mutual inductor; The PLC controller obtains a PLC code value according to the received pre-adjusted current transformation ratio range and a pre-stored current transformation truth table, and switches the current gear according to the PLC code value; After the current gear is switched, the PLC controller calculates and outputs the corresponding rear-end voltage value according to the received transformer secondary signal, the pre-adjusted current transformation ratio range and the pre-stored current transformation truth table; The power current module converts the received back-end voltage value into a current value and transmits the current value to the current measuring device.

9. The current transformation ratio adjustment method according to claim 8, characterized in that: The pre-adjusted current transformation ratio range is obtained through interaction between the user and the touch screen.

10. The current transformation ratio adjustment method according to claim 8, characterized in that: The universal current transformation ratio adjustment system is connected to the secondary side loop of the current transformer.

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