Current transformer polarity tester based on wireless communication technology

Abstract

The utility model discloses a current transformer polarity tester based on a wireless communication technology, which comprises a host unit and three slave units, and the host unit and the three slave units carry out data transmission based on the wireless communication technology. The three slave units are electrically connected with buses of three phase voltages of the primary side of the current transformer respectively, and are used for generating test signals and outputting the test signals to the buses of the three phase voltages of the primary side of the current transformer; the host unit is used for sensing three phase voltages of the secondary side of the current transformer, generating corresponding sensing signals and judging whether the polarity of the current transformer is correct or not through the sensing signals. According to the utility model, the data transmission function of the host unit and the slave unit is realized by using the wireless communication technology, the constraint of a traditional test cable is completely abandoned, the test process becomes more flexible and convenient, the test efficiency is greatly improved, and the system is especially suitable for a rapid test task in a complex field environment.

Description

Technical Field

[0001] This utility model belongs to the field of current transformer testing, and in particular relates to a current transformer polarity tester based on wireless communication technology. Background Technology

[0002] In modern power systems, current transformers are indispensable key devices, and the accuracy of their polarity plays a decisive role in the core functions of accurate metering and reliable protection. Traditional manual current transformer polarity testing methods have many inherent drawbacks. For example, testers must carry a large number of complex test cables and perform tedious connection operations when working in the field. This not only consumes a lot of time and energy, but also makes the testing process susceptible to adverse factors such as electromagnetic interference, low signal-to-noise ratio, and human error in complex and variable field environments. This results in low efficiency and a high risk of misjudgment, making it difficult to meet the urgent needs of modern power systems for efficient and accurate testing.

[0003] Currently available current transformer testing instruments are generally geared towards distribution cabinet scenarios, lacking design and development for the practical application of outdoor high-voltage current transformer polarity testing. Considering the outdoor environment and large size of power transformers, which differ significantly from distribution cabinet scenarios, and the fact that actual construction sites typically involve large outdoor high-voltage transformers with the primary busbar and current transformer mounted on top, existing current transformer testing instruments have significant shortcomings in practicality. Furthermore, existing current transformer polarity testing equipment is a one-piece design, requiring three repeated operations (testing A, B, and C phases of AC separately), resulting in low efficiency. It also requires at least 6 meters of primary side signal transmission cable, which is heavy and inconvenient to carry, failing to adapt well to actual operating environments and exhibiting significant limitations in adaptability. Utility Model Content

[0004] To address the shortcomings of the existing technology, the technical problem to be solved by this utility model is to provide a current transformer polarity tester based on wireless communication technology that can break through the working mode of existing test equipment, has high scenario capability, and provides convenient, efficient and accurate testing.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0006] A current transformer polarity tester based on wireless communication technology includes a master unit and three slave units. The master unit and the three slave units transmit data based on wireless communication technology. The three slave units are electrically connected to the busbars of the three phase voltages on the primary side of the current transformer, respectively, and are used to generate test signals of specified frequency and amplitude, and output the test signals to the busbars of the three phase voltages on the primary side of the current transformer.

[0007] The host unit is used to sense the three phase voltages on the secondary side of the current transformer, generate corresponding sensing signals, and amplify and filter the three sensing signals before converting them into digital signals for processing, thereby determining whether the polarity of the current transformer is correct.

[0008] This invention utilizes wireless communication technology to achieve data transmission between the master and slave units, completely eliminating the constraints of traditional test cables. This makes the testing process more flexible and convenient, significantly improving testing efficiency, and is particularly suitable for rapid testing tasks in complex field environments. Furthermore, through optimized design of the slave and master units, this embodiment significantly enhances the accuracy and anti-interference capabilities of test signals, effectively ensuring the reliability and stability of test results and providing a solid guarantee for the safe operation of the power system. It also enables digital management and in-depth analysis of test data, providing crucial data support for power equipment condition monitoring and fault prediction, and contributing to improved power system operation and maintenance. Attached Figure Description

[0009] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0010] Figure 1 This is a connection diagram of the master unit and three slave units.

[0011] Figure 2 This is a schematic diagram of the main unit.

[0012] Figure 3 This is a circuit diagram of the first and second power supply voltage generation circuits in the host power management module.

[0013] Figure 4 This is a circuit diagram of the third power supply voltage generation circuit in the host power management module.

[0014] Figure 5 This is a circuit diagram of the host's rechargeable lithium battery module.

[0015] Figure 6 This is the circuit diagram of the phase detection module.

[0016] Figure 7 This is the circuit diagram for the storage module.

[0017] Figure 8 This is the circuit diagram for the operation control module.

[0018] Figure 9 Circuit diagram of the host MCU module

[0019] Figure 10 This is a block diagram of the slave unit.

[0020] Figure 11 This is the circuit diagram of the step-down module.

[0021] Figure 12 This is the circuit diagram of the pulse current signal generation module.

[0022] Figure 13 This is the circuit diagram of the slave MCU module. Detailed Implementation

[0023] The following specific examples illustrate the implementation of this utility model. The illustrations provided in the following embodiments are only schematic representations of the basic concept of this utility model. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0024] Please see Figure 1 A preferred embodiment of the current transformer polarity tester based on wireless communication technology includes a master unit 100 and three slave units (i.e., slave unit 201, slave unit 202, and slave unit 203). The master unit 100 and the three slave units transmit data based on wireless communication technology. The three slave units are electrically connected to the busbars of the three phase voltages (i.e., phase A, phase B, and phase C) on the primary side (i.e., the high-voltage side) of the current transformer, respectively, to generate test signals of a specified frequency and amplitude, and output the test signals to the busbars of the three phase voltages on the primary side of the current transformer. The master unit 100 is used to sense the three phase voltages (i.e., phase A, phase B, and phase C) on the secondary side (i.e., the low-voltage side) of the current transformer, generating corresponding induced signals. These induced signals are amplified and filtered, then converted into digital signals for processing, thereby determining whether the polarity of the current transformer is correct.

[0025] The host unit 100 is installed on the secondary side of the current transformer and is equipped with a signal conditioning circuit, an A / D conversion module, and a high-performance microprocessor. The signal conditioning circuit is responsible for filtering, amplifying, and other preprocessing operations on the weak signal induced on the secondary side, effectively eliminating noise interference and significantly improving signal quality. The A / D conversion module quickly and accurately converts the analog signal into a digital signal so that the microprocessor can perform in-depth analysis and accurately determine whether the polarity of the current transformer is correct.

[0026] Please see Figure 2 The host unit 100 includes a host MCU module, a host rechargeable lithium battery module, a host power management module, a host wireless communication module, a host antenna, and three phase detection modules. The host rechargeable lithium battery module is electrically connected to the host power management module, and the host antenna is electrically connected to the host wireless communication module. The host power management module, the host wireless communication module, and the three phase detection modules are all electrically connected to the host MCU module. Each phase detection module is used to sense a phase voltage on the secondary side of the current transformer, generate a corresponding induced signal, amplify and filter the induced signal, and convert it into a digital signal, which is then sent to the host MCU module. The host MCU module is used to determine whether the polarity of the current transformer is correct based on the digital signal, and to transmit data with the three slave units through the host wireless communication module and the host antenna.

[0027] Please see Figure 3 and Figure 4 The host power management module includes resistors R1, R2, R3, and R4; capacitors C1, C2, C3, C4, C5, and C6; capacitors CE1, CE2, CE3, and CE4; diodes D1, D2, D3, and D4; transistor Q1; MOSFET Q2; power chip U1; and power chip U2. In this embodiment, power chip U1 can be a 78M05 chip, and power chip U2 can be an AMS1117 chip.

[0028] Please continue reading. Figure 3 The positive terminal of diode D1 is electrically connected to the host MCU module. The negative terminals of both diode D1 and diode D2 are connected to the power switch. The positive terminal of diode D2 is electrically connected to the collector of transistor Q1 and the first terminal of resistor R4. The transmitter of transistor Q1 is grounded, and the base of transistor Q1 is grounded through resistor R2. The base of transistor Q1 is also electrically connected to the negative terminal of diode D3 through resistor R1. The positive terminal of diode D3 is electrically connected to the host MCU module. The negative terminal of diode D4 is electrically connected to the negative terminal of diode D3, and the positive terminal of diode D4 is electrically connected to the host MCU module.

[0029] The second end of resistor R4 is electrically connected to the gate of field-effect transistor Q2. The second end of resistor R4 is also electrically connected to the source of field-effect transistor Q2 via resistor R3. The source of field-effect transistor Q2 is connected to the output voltage BAT*2 of the host rechargeable lithium battery module. The drain of field-effect transistor Q2 outputs the first supply voltage (i.e., the voltage of the two lithium batteries, approximately 7.4V). The drain of field-effect transistor Q2 is also electrically connected to the input terminal of power chip U1.

[0030] The input pin Vin of the power chip U1 is grounded through capacitor C1. Capacitors CE1, CE2, and CE3 are all connected in parallel with capacitor C1. The ground pin GND of the power chip U1 is grounded. The output pin Vout of the power chip U1 outputs the second supply voltage (i.e., 5V). The output pin Vout of the power chip U1 is grounded through capacitor C2. Capacitor CE4 is connected in parallel with capacitor C2.

[0031] Please continue reading. Figure 4 The input pin Vin of the power chip U2 is connected to the first supply voltage. The input pin Vin of the power chip U2 is grounded through capacitor C3, and capacitor C4 is connected in parallel with capacitor C3. The ground pin GND of the power chip U2 is grounded. The output pin Vout of the power chip U2 outputs the third supply voltage (i.e., 3.3V). The output pin Vout of the power chip U2 is grounded through capacitor C5, and capacitor C6 is connected in parallel with capacitor C5.

[0032] Please see Figure 5 The host rechargeable lithium battery module mainly includes two lithium batteries BT2 and a lithium battery charging circuit. The lithium battery charging circuit mainly includes a power chip U5 and its peripheral circuits. The power chip U5 adopts a CN3302 chip. The host rechargeable lithium battery module uses the voltage of the two lithium batteries BT2 connected in series as its output voltage BAT*2 (approximately 3.7V*2=7.4V). The lithium battery can be charged through the charging port or USB interface. This circuit is an existing conventional circuit and will not be described in detail here.

[0033] Please see Figure 6 The phase detection module includes resistors R36, R37, R38, R39, R40, R41, R42, R43, R44, R45, and R46; capacitors C18 and C19; and operational amplifiers U6A and U6B. In this embodiment, operational amplifiers U6A and U6B are both integrated on the same LM358 chip. Pin 8 (power supply terminal) of the LM358 chip is connected to +5V, and pin 4 (ground terminal) of the LM358 chip is grounded.

[0034] The first end of resistor R37 is electrically connected to the first end of a phase voltage winding on the secondary side of the current transformer, and the second end of resistor R37 is electrically connected to the second end of that phase voltage winding. The first end of resistor R37 is also grounded through resistor R36, and the first end of resistor R37 is also electrically connected to the inverting input terminal of operational amplifier U6A through resistor R39. The second end of resistor R37 is grounded through resistor R38, and the second end of resistor R37 is also electrically connected to the inverting input terminal of operational amplifier U6B through resistor R40. For example, when the phase detection module is used to detect the A-phase voltage on the secondary side of the current transformer, the first end of resistor R37 is electrically connected to the first end of the A-phase voltage winding on the secondary side of the current transformer, and the second end of resistor R37 is electrically connected to the second end of the A-phase voltage winding on the secondary side of the current transformer.

[0035] The inverting input terminal of the operational amplifier U6A is grounded through resistor R42, and the inverting input terminal of the operational amplifier U6A is also electrically connected to its output terminal through resistor R43. The output terminal of the operational amplifier U6A is electrically connected to the first end of resistor R44, and the second end of resistor R44 is electrically connected to the host MCU module for feeding back the detection result to the host MCU module. The second end of resistor R44 is also grounded through capacitor C18.

[0036] The inverting input terminal of operational amplifier U6B is electrically connected to the non-inverting input terminal of operational amplifier U6A. The inverting input terminal of operational amplifier U6B is also grounded through resistor R41, and its output terminal is also electrically connected through resistor R45. The output terminal of operational amplifier U6B is electrically connected to the first end of resistor R46, and the second end of resistor R46 is electrically connected to the host MCU module for feeding back the detection result. The second end of resistor R46 is also grounded through capacitor C19. The non-inverting input terminal of operational amplifier U6B is electrically connected to the inverting input terminal of operational amplifier U6A.

[0037] exist Figure 6In the process, the signals fed back to the host MCU module from the output terminals of operational amplifiers U6A and U6B are used as A-IN-positive and A-IN-negative signals to detect the A-phase voltage on the secondary side of the induced current transformer. Similarly, in the phase detection module for detecting the B-phase voltage on the secondary side of the induced current transformer, the phase detection module is electrically connected to both ends of the B-phase voltage winding on the secondary side of the current transformer, and the signals fed back to the host MCU module from the output terminals of the two operational amplifiers are used as B-IN-positive and B-IN-negative signals to detect the B-phase voltage on the secondary side of the induced current transformer. Likewise, in the phase detection module for detecting the C-phase voltage on the secondary side of the induced current transformer, the phase detection module is electrically connected to both ends of the C-phase voltage winding on the secondary side of the current transformer, and the signals fed back to the host MCU module from the output terminals of the two operational amplifiers are used as C-IN-positive and C-IN-negative signals to detect the C-phase voltage on the secondary side of the induced current transformer.

[0038] In this embodiment, the host unit 100 further includes an operation control module, a storage module, and a display module. The storage module and the display module are both electrically connected to the host MCU module; the operation control module is electrically connected to both the host MCU module and the host power management module. Please refer to [link to relevant documentation]. Figure 7 In this embodiment, the storage module is a FLASH storage unit, including a FLASH storage chip U3 and its peripheral circuitry. The FLASH storage chip U3 can be a W25Q80BVSSIG chip. The display module can be an LCD display screen.

[0039] Please see Figure 8 The operation control module includes a test key switch K1, a left selection key switch K2, a right selection key switch K3, and a power switch K4. The first terminal of the test key switch K1 is electrically connected to the host MCU module, and the second terminal of the test key switch K1 is grounded. The first terminal of the left selection key switch K2 is electrically connected to the host MCU module, and the second terminal of the left selection key switch K2 is grounded. The first terminal of the right selection key switch K3 is electrically connected to the host MCU module, and the second terminal of the right selection key switch K3 is grounded. The first terminal of the power switch K4 is electrically connected to the negative terminal of diode D2 in the host power management module, and the second terminal of the power switch K4 is grounded.

[0040] Please see Figure 9The host MCU module includes an MCU chip U4 and its peripheral circuitry. The MCU chip U4 can be an STC8H4K64TL-45I-LQFP48 chip. The host wireless communication module typically uses a 2.4G module, a Bluetooth module, or a LoRa module, which can be selected according to actual needs. Of course, other wireless communication modules can also be selected. In this embodiment, the host wireless communication module uses a Bluetooth self-organizing network module.

[0041] The slave units (201, 202, 203) integrate a high-precision signal generator and a power amplifier, which can receive test commands from the host via Bluetooth, generate stable test signals of specific frequency and amplitude, and output them to the primary bus of the current transformer; the three slave units (201, 202, 203) can have the same structure.

[0042] Please see Figure 10 The slave units (201, 202, 203) include a slave MCU module, a slave rechargeable lithium battery module, a slave power management module, a slave wireless communication module, a slave antenna, a step-down module, and a pulse current signal generation module. The slave rechargeable lithium battery module is electrically connected to the slave power management module, the slave antenna is electrically connected to the slave wireless communication module, and the slave power management module, slave wireless communication module, step-down module, and pulse current signal generation module are all electrically connected to the slave MCU module.

[0043] The step-down module is used to step down the power supply voltage output by the slave power management module and then supply power to the pulse current signal generation module through the slave MCU module to save power. The slave MCU module is used to transmit data with the master unit 100 through the slave wireless communication module and the slave antenna, and to cause the pulse current signal generation module to generate a test signal of a specified frequency and amplitude according to the instructions sent by the master unit 100.

[0044] Please see Figure 11The step-down module includes resistors R58, R60, R61, R62, R63, R64, R65, R66, R67, R68, R69, R70, R71, R72, R73, R74, R75, R76, R77, R78, R79, R80, inductor L1, capacitor C20, and capacitor [missing information]. C21, capacitors C22, C23, C24, C26, C27, C28, C29, C30, C31, C32, Zener diode D6, Zener diode D7, LED2, LED7, transistors Q9, Q10, Q11, Q12, operational amplifier U14B, linear current sensor chip U15, and power supply chip U16. The linear current sensor chip U15 can be an ACS712T chip, and the power supply chip U16 can be an XL4016E1 chip.

[0045] The input pin Vin of the power chip U16 is connected to the first supply voltage. The input pin Vin of the power chip U16 is also grounded through capacitor C21, and capacitor C22 is connected in parallel with capacitor C21. The power supply pin VC of the power chip U16 is connected to the first supply voltage through capacitor C20; the ground pin GND of the power chip U16 is grounded.

[0046] The output pin OUT of the power chip U16 is electrically connected to the negative terminals of Zener diodes D6 and D7, respectively. The positive terminals of both Zener diodes D6 and D7 are grounded. The output pin OUT of the power chip U16 is also electrically connected to the first terminal of inductor L1, and the second terminal of inductor L1 outputs a fourth supply voltage OUT. The second terminal of inductor L1 is also electrically connected to the feedback pin FB of the power chip U16 through resistor R60, and the feedback pin FB of the power chip U16 is grounded through resistor R67.

[0047] The feedback pin FB of the power chip U16 is also electrically connected to the collector of transistor Q9 through resistor R69. The base of transistor Q9 is electrically connected to the slave MCU module through resistor R71, and the emitter of transistor Q9 is electrically connected to the slave MCU module through resistor R73. The feedback pin FB of the power chip U16 is also electrically connected to the collector of transistor Q10 through resistor R70. The base of transistor Q10 is electrically connected to the slave MCU module through resistor R72, and the emitter of transistor Q10 is electrically connected to the slave MCU module through resistor R74.

[0048] The feedback pin FB of the power chip U16 is also electrically connected to the collector of transistor Q11 through resistor R76. The base of transistor Q11 is electrically connected to the slave MCU module through resistor R78, and the emitter of transistor Q11 is electrically connected to the slave MCU module through resistor R80. The feedback pin FB of the power chip U16 is also electrically connected to the collector of transistor Q12 through resistor R75. The base of transistor Q12 is electrically connected to the slave MCU module through resistor R77, and the emitter of transistor Q12 is electrically connected to the slave MCU module through resistor R79.

[0049] The second terminal of inductor L1 is also grounded through capacitor C23. Capacitors C26, C27, C28, C29, and C30 are all connected in parallel with capacitor C23. The second terminal of inductor L1 is also electrically connected to the positive terminal of LED2, and the negative terminal of LED2 is grounded through resistor R64. The second terminal of inductor L1 is also electrically connected to the first terminal of resistor R66 through resistor R61, and the second terminal of resistor R66 is grounded. The first terminal of resistor R66 is also electrically connected to the first terminal of capacitor C32 through resistor R68. The first terminal of capacitor C32 is electrically connected to the slave MCU module, and the second terminal of capacitor C32 is grounded.

[0050] The second terminal of inductor L1 is also electrically connected to the detection input pin IP+ of linear current sensor chip U15 through resistor R58. The detection output pin IP- of linear current sensor chip U15 outputs the fifth supply voltage OUT-X. The detection output pin IP- of linear current sensor chip U15 is also electrically connected to the positive terminal of light-emitting diode LED7 through resistor R63. The negative terminal of light-emitting diode LED7 is grounded.

[0051] The power supply pin VCC of the linear current sensor chip U15 is connected to a second supply voltage. The detection output pin VOUT of the linear current sensor chip U15 is electrically connected to the non-inverting output pin of the operational amplifier U14B. The Hall effect connection pin FILTER of the linear current sensor chip U15 is grounded through capacitor C24, and the ground pin GND of the linear current sensor chip U15 is grounded. The inverting output pin of the operational amplifier U14B is grounded through resistor R62, and the inverting output pin of the operational amplifier U14B is also electrically connected to its output pin through resistor R65. The capacitor C31 is connected in parallel with the resistor R65, and the output pin of the operational amplifier U14B is electrically connected to the slave MCU module.

[0052] Please see Figure 12The pulse current signal generation module includes resistors R12, R16, R18, R19, R20, R59, R120, R121, and R122, capacitor C9, Zener diode D11, transistor Q20, field-effect transistor Q21, and operational amplifier U14A. The emitter of transistor Q20 is connected to a second supply voltage, and the emitter of transistor Q20 is also electrically connected to its base through resistor R12. The base of transistor Q20 is electrically connected to the slave MCU module through resistor R16. The collector of transistor Q20 is grounded through resistor R18, and the collector of transistor Q20 is also electrically connected to the gate of field-effect transistor Q21.

[0053] The drain of the field-effect transistor Q21 is electrically connected to the positive terminal of the Zener diode D11, and the negative terminal of the Zener diode D11 is connected to the fifth supply voltage OUT-X. The resistor R59 is connected in parallel with the Zener diode D11. The two ends of the Zener diode D11 are also electrically connected to the input side (the side where the voltage on the bus enters the current transformer) and the output side (the other side of the bus corresponding to the current transformer) of a phase bus on the primary side of the current transformer, respectively. The source of the field-effect transistor Q21 is grounded through resistor R20. The source of the field-effect transistor Q21 is also electrically connected to the non-inverting input terminal of the operational amplifier U14A through resistor R19. The non-inverting input terminal of the operational amplifier U14A is grounded through capacitor C9. The inverting input terminal of the operational amplifier U14A is grounded through resistor R122. The inverting input terminal of the operational amplifier U14A is also electrically connected to its output terminal through resistor R121. The output terminal of the operational amplifier U14A is electrically connected to the slave MCU module through resistor R120.

[0054] Please see Figure 13 The slave MCU module includes an MCU chip U11 and its peripheral circuitry. The MCU chip U11 can be an STC8H4K64TL-45I-LQFP48 chip. Furthermore, the circuit structure of the slave rechargeable lithium battery module can be the same as that of the host rechargeable lithium battery module; for details, please refer to [reference needed]. Figure 5 The circuit structure of the slave power management module can be the same as that of the master power management module; please refer to [reference needed]. Figure 3 and Figure 4 The slave wireless communication module uses the same type of communication module as the master wireless communication module. In this embodiment, the slave wireless communication module uses a Bluetooth self-organizing network module.

[0055] The working principle of this embodiment is as follows:

[0056] Please see Figures 1 to 13In use, slave unit 201 is connected to the A-phase bus on both the incoming and outgoing sides of the current transformer, slave unit 202 is connected to the B-phase bus on both the incoming and outgoing sides of the current transformer, and slave unit 203 is connected to the C-phase bus on both the incoming and outgoing sides of the current transformer, forming a three-phase signal transmission circuit. The three slave units are then powered on and their corresponding test phases are set (i.e., slave unit 201 is set to phase A, slave unit 202 to phase B, and slave unit 203 to phase C), awaiting pairing with the master unit 100. To save power, the slave units are designed to step down the power supply output voltage using a step-down module, providing four current outputs of 1A, 2A, 3A, and 5A. The reduced current is then fed into the slave MCU module, where the MCU chip U11 controls the power supply to the pulse current signal generation module.

[0057] Then, the three phase detection modules of the master unit 100 are connected to the A-phase voltage winding, B-phase voltage winding, and C-phase voltage winding on the secondary side of the current transformer, respectively, to form a signal receiving loop. The unit is then powered on, enabling the master unit 100 and the three slave units to pair and connect via Bluetooth self-organizing network technology, forming a one-to-many network. In this way, the MCU chip U4 of the master MCU module of the master unit 100 can send commands to the three slave units and receive information such as the operating status of the three slave units through this network.

[0058] According to the specifications of the current transformer under test, the user sets the specifications of the test signals sent by each slave unit on the master unit 100 side, including parameters such as signal frequency and amplitude. After the settings are completed, the MCU chip U4 of the master MCU module sends the test command to the three slave units through the wireless communication network, and then waits to receive the induced pulsating current signal.

[0059] After receiving the instruction sent by the master unit 100, the slave unit parses the instruction through the MCU chip U11 of the slave MCU module and controls the pulse current signal generation module to output the pulse current signal according to the current pulse parameters set in the test instruction.

[0060] After the host unit 100 receives the induced signal on the secondary winding of the current sensor, due to the small induced current, the operational amplifier module of the phase detection module first amplifies the signal. Then, the bandpass filter circuit of the phase detection module filters the received signal to remove noise signals with large frequency differences. The filtered signal is then sent to the MCU chip U4 of the host MCU module for further analysis and processing. The MCU chip U4 performs frequency and amplitude matching on the received current signal to determine whether the signal is received normally. If received normally, the MCU chip U4 determines the polarity of the secondary winding by checking the phase of the current signal and displays the test result on the LCD screen. When the host unit 100 completes the polarity determination of the secondary windings of phases A, B, and C, the test process ends. At this time, the MCU chip U4 of the host unit 100 sends a stop test command to each slave unit. Upon receiving the command, the MCU chip U11 of the slave unit stops sending test signals and enters a waiting state, thus completing one detection process.

[0061] In this embodiment, by utilizing wireless communication technologies such as Bluetooth self-organizing networks, the constraints of traditional test cables are completely eliminated, making the testing process more flexible and convenient, and significantly improving testing efficiency, especially suitable for rapid testing tasks in complex field environments. Bluetooth self-organizing network technology also features flexible networking among multiple test devices, capable of handling test scenarios of varying scales. Furthermore, this embodiment, through optimized design of the slave unit (i.e., signal transmitting module) and the master unit 100 (i.e., signal receiving module), significantly enhances the accuracy and anti-interference capability of test signals, effectively ensuring the reliability and stability of test results, and providing a solid guarantee for the safe operation of the power system. It also enables digital management and in-depth analysis of test data, providing crucial data support for power equipment status monitoring and fault prediction, and contributing to improving the operation and maintenance level of the power system.

[0062] The above embodiments only illustrate preferred implementations of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A current transformer polarity tester based on wireless communication technology, characterized in that: It includes a master unit and three slave units, which transmit data based on wireless communication technology; the three slave units are electrically connected to the busbars of the three phase voltages on the primary side of the current transformer, respectively, and are used to generate test signals of a specified frequency and amplitude, and output the test signals to the busbars of the three phase voltages on the primary side of the current transformer. The host unit is used to sense the three phase voltages on the secondary side of the current transformer, generate corresponding sensing signals, and amplify and filter the three sensing signals before converting them into digital signals for processing, thereby determining whether the polarity of the current transformer is correct.

2. The current transformer polarity tester based on wireless communication technology as described in claim 1, characterized in that: The host unit includes a host MCU module, a host rechargeable lithium battery module, a host power management module, a host wireless communication module, a host antenna, and three phase detection modules. The host rechargeable lithium battery module is electrically connected to the host power management module, the host antenna is electrically connected to the host wireless communication module, and the host power management module, the host wireless communication module, and the three phase detection modules are all electrically connected to the host MCU module. Each phase detection module is used to sense a phase voltage on the secondary side of the current transformer to generate a corresponding induced signal, and amplifies and filters the induced signal before converting it into a digital signal and sending it to the host MCU module. The host MCU module is used to determine whether the polarity of the current transformer is correct based on the digital signal, and to transmit data with the three slave units through the host wireless communication module and the host antenna.

3. The current transformer polarity tester based on wireless communication technology as described in claim 2, characterized in that: The host power management module includes resistors R1, R2, R3, and R4; capacitors C1, C2, C3, C4, C5, and C6; capacitors CE1, CE2, CE3, and CE4; diodes D1, D2, D3, and D4; transistor Q1; field-effect transistor Q2; power chip U1; and power chip U2. The positive terminal of diode D1 is electrically connected to the host MCU module. The negative terminals of both diode D1 and diode D2 are connected to the power switch. The positive terminal of diode D2 is electrically connected to the collector of transistor Q1 and the first terminal of resistor R4, respectively. The transmitter of transistor Q1 is grounded, and the base of transistor Q1 is grounded through resistor R2. The base of transistor Q1 is also electrically connected to the negative terminal of diode D3 through resistor R1. The positive terminal of diode D3 is electrically connected to the host MCU module. The negative terminal of diode D4 is electrically connected to the negative terminal of diode D3, and the positive terminal of diode D4 is electrically connected to the host MCU module. The second end of the resistor R4 is electrically connected to the gate of the field-effect transistor Q2. The second end of the resistor R4 is also electrically connected to the source of the field-effect transistor Q2 through the resistor R3. The source of the field-effect transistor Q2 is connected to the output voltage BAT*2 of the host rechargeable lithium battery module. The drain of the field-effect transistor Q2 outputs the first supply voltage. The drain of the field-effect transistor Q2 is also electrically connected to the input terminal of the power chip U1. The input pin Vin of the power chip U1 is grounded through capacitor C1, and capacitors CE1, CE2 and CE3 are all connected in parallel with capacitor C1; the ground pin GND of the power chip U1 is grounded, and the output pin Vout of the power chip U1 outputs the second supply voltage. The output pin Vout of the power chip U1 is grounded through capacitor C2, and capacitor CE4 is connected in parallel with capacitor C2. The input pin Vin of the power chip U2 is connected to the first power supply voltage. The input pin Vin of the power chip U2 is grounded through capacitor C3, and capacitor C4 is connected in parallel with capacitor C3. The ground pin GND of the power chip U2 is grounded. The output pin Vout of the power chip U2 outputs the third power supply voltage. The output pin Vout of the power chip U2 is grounded through capacitor C5, and capacitor C6 is connected in parallel with capacitor C5.

4. The current transformer polarity tester based on wireless communication technology as described in claim 2, characterized in that: The phase detection module includes resistors R36, R37, R38, R39, R40, R41, R42, R43, R44, R45, and R46; capacitors C18 and C19; and operational amplifiers U6A and U6B. The first end of resistor R37 is electrically connected to the first end of a phase voltage winding on the secondary side of the current transformer, and the second end of resistor R37 is electrically connected to the second end of the phase voltage winding. The first end of resistor R37 is also grounded through resistor R36, and the first end of resistor R37 is also electrically connected to the inverting input terminal of operational amplifier U6A through resistor R39. The second end of resistor R37 is grounded through resistor R38, and the second end of resistor R37 is also electrically connected to the inverting input terminal of operational amplifier U6B through resistor R40. The inverting input terminal of the operational amplifier U6A is grounded through resistor R42. The inverting input terminal of the operational amplifier U6A is also electrically connected to its output terminal through resistor R43. The output terminal of the operational amplifier U6A is electrically connected to the first terminal of resistor R44. The second terminal of resistor R44 is electrically connected to the host MCU module. The second terminal of resistor R44 is also grounded through capacitor C18. The inverting input terminal of operational amplifier U6B is electrically connected to the non-inverting input terminal of operational amplifier U6A. The inverting input terminal of operational amplifier U6B is also grounded through resistor R41. The inverting input terminal of operational amplifier U6B is also electrically connected to its output terminal through resistor R45. The output terminal of operational amplifier U6B is electrically connected to the first end of resistor R46. The second end of resistor R46 is electrically connected to the host MCU module. The second end of resistor R46 is also grounded through capacitor C19. The non-inverting input terminal of operational amplifier U6B is electrically connected to the inverting input terminal of operational amplifier U6A.

5. A current transformer polarity tester based on wireless communication technology as described in claim 2, characterized in that: The host unit also includes an operation control module, which includes a test key switch K1, a left selection key switch K2, a right selection key switch K3, and a power switch K4. The first terminal of the test key switch K1 is electrically connected to the host MCU module, and the second terminal of the test key switch K1 is grounded; the first terminal of the left selection key switch K2 is electrically connected to the host MCU module, and the second terminal of the left selection key switch K2 is grounded; the first terminal of the right selection key switch K3 is electrically connected to the host MCU module, and the second terminal of the right selection key switch K3 is grounded; the first terminal of the power switch K4 is electrically connected to the host power management module, and the second terminal of the power switch K4 is grounded.

6. The current transformer polarity tester based on wireless communication technology as described in claim 2, characterized in that: The host unit also includes a storage module and a display module, both of which are electrically connected to the host MCU module.

7. A current transformer polarity tester based on wireless communication technology as described in claim 2, characterized in that: The host wireless communication module is a 2.4G module, a Bluetooth module, or a LoRa module.

8. A current transformer polarity tester based on wireless communication technology as described in any one of claims 2 to 7, characterized in that: The slave unit includes a slave MCU module, a slave rechargeable lithium battery module, a slave power management module, a slave wireless communication module, a slave antenna, a step-down module, and a pulse current signal generation module. The slave rechargeable lithium battery module is electrically connected to the slave power management module, the slave antenna is electrically connected to the slave wireless communication module, and the slave power management module, slave wireless communication module, step-down module, and pulse current signal generation module are all electrically connected to the slave MCU module. The step-down module is used to step down the power supply voltage output by the slave power management module and then power the pulse current signal generation module through the slave MCU module. The slave MCU module is used to transmit data with the master unit through the slave wireless communication module and the slave antenna, and to cause the pulse current signal generation module to generate a test signal of a specified frequency and amplitude according to the instructions sent by the master unit.

9. A current transformer polarity tester based on wireless communication technology as described in claim 8, characterized in that: The step-down module includes resistors R58, R60, R61, R62, R63, R64, R65, R66, R67, R68, R69, R70, R71, R72, R73, R74, R75, R76, R77, R78, R79, R80, inductor L1, capacitor C20, and capacitor C.

21. Capacitors C22, C23, C24, C26, C27, C28, C29, C30, C31, C32; Zener diode D6; Zener diode D7; LED2; LED7; Transistor Q9; Transistor Q10; Transistor Q11; Transistor Q12; Operational amplifier U14B; Linear current sensor chip U15; and power supply chip U16. The input pin Vin of the power chip U16 is connected to the first supply voltage. The input pin Vin of the power chip U16 is also grounded through capacitor C21. The capacitor C22 is connected in parallel with the capacitor C21. The power supply pin VC of the power chip U16 is connected to the first supply voltage through capacitor C20. The ground pin GND of the power chip U16 is grounded. The output pin OUT of the power chip U16 is electrically connected to the negative terminals of Zener diodes D6 and D7, respectively, and the positive terminals of Zener diodes D6 and D7 are both grounded. The output pin OUT of the power chip U16 is also electrically connected to the first terminal of inductor L1, and the second terminal of inductor L1 outputs a fourth supply voltage OUT. The second terminal of inductor L1 is also electrically connected to the feedback pin FB of the power chip U16 through resistor R60, and the feedback pin FB of the power chip U16 is grounded through resistor R67. The feedback pin FB of the power chip U16 is also electrically connected to the collector of transistor Q9 through resistor R69. The base of transistor Q9 is electrically connected to the slave MCU module through resistor R71, and the emitter of transistor Q9 is electrically connected to the slave MCU module through resistor R73. The feedback pin FB of the power chip U16 is also electrically connected to the collector of transistor Q10 through resistor R70. The base of transistor Q10 is electrically connected to the slave MCU module through resistor R72, and the emitter of transistor Q10 is electrically connected to the slave MCU module through resistor R74. The feedback pin FB of the power chip U16 is also electrically connected to the collector of transistor Q11 through resistor R76. The base of transistor Q11 is electrically connected to the slave MCU module through resistor R78, and the emitter of transistor Q11 is electrically connected to the slave MCU module through resistor R80. The feedback pin FB of the power chip U16 is also electrically connected to the collector of transistor Q12 through resistor R75. The base of transistor Q12 is electrically connected to the slave MCU module through resistor R77, and the emitter of transistor Q12 is electrically connected to the slave MCU module through resistor R79. The second terminal of the inductor L1 is also grounded through capacitor C23. Capacitors C26, C27, C28, C29, and C30 are all connected in parallel with capacitor C23. The second terminal of the inductor L1 is also electrically connected to the positive terminal of the light-emitting diode LED2. The negative terminal of the light-emitting diode LED2 is grounded through resistor R64. The second end of the inductor L1 is also electrically connected to the first end of the resistor R66 through the resistor R61, and the second end of the resistor R66 is grounded; the first end of the resistor R66 is also electrically connected to the first end of the capacitor C32 through the resistor R68, and the first end of the capacitor C32 is electrically connected to the slave MCU module, and the second end of the capacitor C32 is grounded. The second end of the inductor L1 is also electrically connected to the detection input pin IP+ of the linear current sensor chip U15 through resistor R58. The detection output pin IP- of the linear current sensor chip U15 outputs the fifth supply voltage OUT-X. The detection output pin IP- of the linear current sensor chip U15 is also electrically connected to the positive terminal of the light-emitting diode LED7 through resistor R63. The negative terminal of the light-emitting diode LED7 is grounded. The power supply pin VCC of the linear current sensor chip U15 is connected to the second power supply voltage. The detection output pin VOUT of the linear current sensor chip U15 is electrically connected to the non-inverting output of the operational amplifier U14B. The Hall connection pin FILTER of the linear current sensor chip U15 is grounded through capacitor C24. The ground pin GND of the linear current sensor chip U15 is grounded. The inverting output terminal of the operational amplifier U14B is grounded through resistor R62. The inverting output terminal of the operational amplifier U14B is also electrically connected to its output terminal through resistor R65. The capacitor C31 is connected in parallel with resistor R65. The output terminal of the operational amplifier U14B is electrically connected to the slave MCU module.

10. A current transformer polarity tester based on wireless communication technology as described in claim 9, characterized in that: The pulse current signal generation module includes resistors R12, R16, R18, R19, R20, R59, R120, R121, R122, capacitor C9, Zener diode D11, transistor Q20, MOSFET Q21, and operational amplifier U14A. The emitter of transistor Q20 is connected to a second power supply voltage. The emitter of transistor Q20 is also electrically connected to its base through resistor R12. The base of transistor Q20 is electrically connected to the slave MCU module through resistor R16. The collector of transistor Q20 is grounded through resistor R18. The collector of transistor Q20 is also electrically connected to the gate of field-effect transistor Q21. The drain of the field-effect transistor Q21 is electrically connected to the positive terminal of the Zener diode D11, the negative terminal of the Zener diode D11 is connected to the fifth supply voltage OUT-X, the resistor R59 is connected in parallel with the Zener diode D11, and the two ends of the Zener diode D11 are also electrically connected to the input side and the output side of a phase bus of the primary side of the current transformer, respectively. The source of the field-effect transistor Q21 is grounded through resistor R20. The source of the field-effect transistor Q21 is also electrically connected to the non-inverting input terminal of the operational amplifier U14A through resistor R19. The non-inverting input terminal of the operational amplifier U14A is grounded through capacitor C9. The inverting input terminal of the operational amplifier U14A is grounded through resistor R122. The inverting input terminal of the operational amplifier U14A is also electrically connected to its output terminal through resistor R121. The output terminal of the operational amplifier U14A is electrically connected to the slave MCU module through resistor R120.

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