A wireless secondary circuit intelligent detector and detection method thereof

Abstract

The present invention relates to a wireless secondary circuit intelligent detector, wherein the host comprises a transmitting antenna, a tuner, a mixer, a local oscillator module, an oscillation module, a main control module, a data communication module, a human-machine interface module and a transmitting antenna; the slave comprises a receiving antenna, a filtering module, a detector, a main control module, a data communication module and a wireless communication module. The present invention also relates to a detection method of a wireless secondary circuit intelligent detector, wherein the present invention adopts radio frequency technology and uses a secondary line core to be checked as a transmitting antenna of a radio frequency signal.

Description

Technical Field

[0001] The invention belongs to the technical field of tools and instruments, and in particular relates to a wireless secondary loop detector and a detection method thereof. Background Art

[0002] The substation relay protection system is a system formed by connecting various primary and secondary equipment such as relay protection and safety automatic devices, monitoring automation equipment, circuit breakers, current (voltage) transformers, etc. through secondary cables. The specific cores in the secondary cable are wired between different devices according to the design requirements. After being connected to each other, a connected circuit system with unique functions such as control and monitoring of substation equipment is formed, which is called a secondary circuit. The secondary circuit is the blood system of the entire substation relay protection system, and its correctness is crucial to the reliable operation of the entire substation relay protection system. One of the key points of the correctness of the secondary circuit is to ensure that the secondary cores connecting different devices according to the design requirements are the same cores in the same cable, and no deviations can occur. Otherwise, it means that the entire connected circuit system has deviations and cannot achieve its intended functions. The wiring accuracy of the secondary circuit can be as follows Figure 1 The enumeration instructions are shown.

[0003] like Figure 1 As shown in the figure, A-1, B-2, and C-3 are the three cores of the cable, of which A, B, and C are connected to the terminal block of the device on the A side, and 1, 2, and 3 are connected to the terminal block of the device on the B side. An important task of secondary circuit detection is to ensure that the above cores are connected to the determined positions of the devices on both sides to prevent misconnection. For example, A, B, and C on the A side are all correctly wired, but the corresponding positions on the B side are actually wired as 2, 3, and 1, that is, mixed connection occurs, which is called secondary wiring error.

[0004] Substation relay protection systems involve many secondary circuits. In the current construction, renovation, and overhaul of primary and secondary equipment in substations, thousands of secondary wire cores are usually involved, and most secondary cables are tens or even thousands of meters long. Therefore, the inspection of the authenticity of secondary wire core wiring is a time-consuming, labor-intensive, and labor-intensive task. Figure 1 The currently commonly used methods are briefly described as follows:

[0005] According to the design specifications, the substation system has an interconnected ground network, which will extend to all equipment in the substation. All equipment is equipped with grounding copper bars at special locations to connect to the substation ground network. Before wiring, first check the two sides of the wire core to be connected before wiring. Due to the long cable length, for the A-1 wire core, it is impossible to directly use the multimeter resistance range to connect the wire cores A and 1 to form a circuit path. Usually, the test line is used to connect the wire core A to the ground network on one side (such as side A), and the test line is used to connect one end of the multimeter to 1 on the other side, and the other end is connected to the ground network, thereby forming a circuit path, and the test voltage is added through the on-off range of the multimeter to determine the correctness of the wire core. There are three reasons that affect the work efficiency of this work: First, test wiring is required, which consumes manpower and time. Second, due to the presence of multiple joints, poor contact often occurs. This situation often occurs when the test line is connected to the grounding copper plate of the equipment. The outer layer of the grounding copper plate is exposed, and dust, stains accumulate or the surface is oxidized for a long time. After connecting the test line in this way, the connectivity of the entire circuit is not very good, and misjudgment incidents occur from time to time, affecting the accuracy and efficiency of detection. Thirdly, the grounding copper plate is poorly connected to the main ground grid. This situation will also affect the accuracy and efficiency of detection. According to the statistical analysis of the production site, after the test wiring is completed, the misjudgment rate caused by the above three reasons due to the wrong wiring detected accounts for 58%. Therefore, it takes a lot of time to adjust and change the test wiring, which results in a decrease in work efficiency. The more secondary circuits that need to be installed, the more prominent this problem is. Based on this, new test instruments and methods are needed to replace the current test methods to improve detection accuracy and work efficiency. Summary of the invention

[0006] The object of the present invention is to provide a wireless secondary loop detector and a detection method thereof which can improve detection accuracy and work efficiency.

[0007] The technical solution of the present invention:

[0008] A wireless secondary circuit intelligent detector comprises a host and a slave, wherein the host comprises a transmitting antenna, a tuner, a mixer, a local oscillator module, an oscillation module, a main control module, a data communication module, a human-machine interface and a wireless communication module; the main control module communicates data information with the human-machine interface, the oscillation module, the local oscillator module and the data communication module, wherein two-way data communication is performed with the human-machine interface and the data communication module, the human-machine interface and the data communication module receive data and command information sent by the main control module, and transmit various data back to the main control module; the local oscillator module and the oscillation module receive control command information from the main control module and complete corresponding operations; the mixer mixes and superimposes different frequency signals generated by the local oscillator module and the oscillation module, and then sends the signal to the tuner, which modulates and amplifies the signal strength to a set signal strength and then transmits the high-frequency electromagnetic signal through the transmitting antenna; the data communication module receives the data and control information of the main control module, and exchanges the data information with the slave through the wireless communication module.

[0009] Further, the slave includes a receiving antenna, a filtering module, a detector, a main control module, a data communication module, a wireless communication module and a human-machine interface;

[0010] The main control module communicates data information with the data communication module, the human-machine interface, the filter module, and the detector. The main control module communicates data with the human-machine interface module and the data communication module in a two-way manner. The human-machine interface module and the data communication module receive data information sent by the main control module.

[0011] The main control module sends the electromagnetic signal of the frequency that needs to be passed to the detector to the filter module. The detector determines whether the filter module sends an electromagnetic signal of a certain intensity and sends the result to the main control module.

[0012] The data communication module receives the data and control information of the main control module, and exchanges the data information with the host through the wireless communication module;

[0013] The host and the slave communicate wirelessly via a wireless communication module.

[0014] Furthermore, the working process of the host is as follows: after the instrument is powered on, it first completes the data communication self-check with the slave, and after the data communication is normal, it starts to enter the working state; the local oscillator module generates a sine wave signal with a frequency of f0 and an intensity of -5dbm. After the human-machine interface sets the input core wire length L, the main control CPU obtains the corresponding frequency parameter A and inputs the numerical value A to the oscillation module; then the value A is sent to the slave, and after the slave responds, the host waits for the slave test completion signal; after the main control CPU receives the detection success logic signal from the slave, it controls the local oscillator module and the oscillation module to stop outputting signals, and sends the slave response information;

[0015] The host oscillation module is used to generate a frequency f corresponding to the value A. A The sine wave signal is sent to the mixer, and the mixer outputs a frequency of f = f0 + f A , 200mv amplitude, a sine wave signal with a power of -5dbm and an amplitude of 3v is sent to the tuner, and the tuner outputs a sine wave signal with a frequency of f and an intensity of 40dbm to the antenna; the host sends the value A to the slave through the wireless communication module; thereafter, the tuner continues to send a sine wave signal with a frequency of f, an intensity of 40dbm and an amplitude of 3v.

[0016] Furthermore, the slave working process is as follows: after the slave is powered on, it first completes the data communication status self-check procedure with the host, and then enters the working state after the communication is normal; it continues to wait for the reception of the f sent by the host. A If the value is received normally, a prompt message will be sent to the human-machine interface module, and the filter's frequency band will be controlled to be f; at this time, the detector will always monitor the electromagnetic wave information output by the filter module; when the signal strength>10dbm signal is detected, the logic instruction of receiving the signal will be sent to the main control CPU; after receiving the logic instruction of the detector, the main control CPU will send information to the human-machine interface, and send the detection success logic information to the data communication module, waiting for the host to respond.

[0017] Furthermore, the host software process is as follows:

[0018] After the device is powered on, it completes parameter self-check and initialization, and then starts to establish a communication connection with the slave. After the data communication with the slave is normal within a certain time, the local oscillator module is controlled to send a local oscillator signal. After an abnormality, it is processed according to interrupt procedure 1. Then wait for the human-machine module to input the parameter information of the cable core length, and obtain the frequency f according to the parameter information. A and sends it to the oscillation module and the data communication module; then, within a certain period of time, it is determined whether the slave has received f A If there is data, it will enter interrupt program 2, if not, it will enter interrupt program 1; after interrupt program 2 is executed, it will send f to the oscillation module A After that, poll and wait for the data detection information of the slave; if the transmission success information is received, the command to stop working is sent to the oscillator module and the local oscillator module, otherwise, it is processed according to the invisible abnormal situation detected; the interrupt 1 generated by the host program has two aspects, one is when establishing data communication status with the slave, the abnormal setting flag 1, and the second is the slave receiving the host f A response; after the response times out, flag 2 is set and interrupt 1 is generated. After the interrupt 1 program is executed, the abnormal working situation is handled according to flag 1 and flag 2, and an abnormal information prompt is sent to the human-machine interface module.

[0019] Furthermore, the slave software process is as follows:

[0020] After the device is powered on, it completes parameter self-check and initialization, and then starts to establish a communication connection with the host. After the data communication with the host is normal within a certain time, wait for the host to send f A ; After the exception, set the flag 1 and generate an interrupt; receive f within a certain time A After that, it is sent to the filtering module, and a prompt detection message is sent to the human-machine interface module; after that, the main control program constantly loops to detect whether the detector has a signal output. If so, the detection success logic information is sent to the host, and a prompt message is sent to the human-machine interface; if not, it is determined whether there is manual operation on the abnormal situation. If so, flag 2 is set and an interrupt is generated; the interrupt program completes the exception handling, determines flag 1, and completes the exception handling of the communication failure with the host; flag 2 detects the occurrence of invisible abnormal conditions to the host and completes the exception handling.

[0021] A wireless secondary circuit intelligent detection method adopts radio frequency technology and uses a secondary core to be checked as a transmitting antenna for radio frequency signals; a host is used on one side of the detected core and is responsible for generating radio frequency signals and injecting the signals into the core for transmission; a slave is used on the other side of the detected core and determines whether the host and the slave are connected to the same core by detecting the difference in the strength of the radio frequency signal of the tested core and the radio frequency signal of the non-tested core, thereby achieving the purpose of secondary circuit detection. The host and the slave communicate data via wireless signals.

[0022] Preferably, the calculation formula of the antenna length and frequency is:

[0023] Where c is the speed of light and f is the frequency.

[0024] Preferably, the longest cable length of the substation is less than 2 km, and the highest frequency of the transmitted signal is calculated to be:

[0025] f=37.5kHz, considering the margin, the highest frequency of the transmitted signal is 30kHz.

[0026] Preferably, the parameter value relationship between the cable core length and the transmission frequency is as follows: when the length is less than 50 meters, the frequency is 25kHz; when the length is 50-400 meters, the frequency is 22.5kHz; when the length is 400-800 meters, the frequency is 19.5kHz; when the length is 800-1300 meters, the frequency is 17.5kHz; when the length is 1300-1800 meters, the frequency is 19.5kHz; when the length is greater than 1800 meters, the frequency is 23.5kHz.

[0027] Beneficial effects of the present invention:

[0028] The present invention avoids the disadvantages of low efficiency and high false detection rate in the current detection of secondary circuits of substations by using a multimeter in combination with the equipment ground network for test wiring to form a connection circuit for detection. Through actual on-site detection, the efficiency of the detector of the present invention is improved by more than 40%, and the false detection rate is 0. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The following is a diagram illustrating the wiring accuracy of the secondary circuit of the background technology of the present invention;

[0030] Figure 2 This is a hardware structure diagram of the host computer of the present invention;

[0031] Figure 3 This is a hardware structure diagram of the slave device of the present invention;

[0032] Figure 4 This is a flow chart of the host software of the present invention;

[0033] Figure 5 This is a flow chart of the slave software of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0036] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so that once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0037] In the description of the present application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0038] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0039] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0040] The detector of the present invention adopts radio frequency technology and uses the secondary core to be checked as a transmitting antenna for radio frequency signals. The instrument is divided into a master and a slave. The master is used on one side of the tested core and is responsible for generating radio frequency signals and injecting the signal into the core for transmission. The slave is used on the other side of the tested core and determines whether the master and the slave are connected to the same core by detecting the difference in the radio frequency signal strength of the tested core and the non-tested core, thereby achieving the purpose of secondary circuit detection. The master and the slave communicate data via wireless signals. This test method does not require test wiring, effectively avoids the shortcomings of existing methods, and improves detection accuracy and work efficiency.

[0041] Example 1

[0042] Determination of the basic principles and relevant technical parameters of the present invention:

[0043] Different from the existing radio receiving device. The existing radio receiving device mainly uses radio waves to radiate electromagnetic waves into space to transmit signals. The detector of the present invention mainly ensures that the radio frequency signal propagates in the conductor, and the energy radiated into the space is as low as possible. According to electromagnetic theory, the larger the frequency of the radio frequency signal, the greater the propagation loss of the signal in a good solid conductor, and the smaller the energy loss of propagation in the electrolyte. Therefore, the greater the energy radiated by the high-frequency signal from the propagated metal conductor to the space, the stronger the radio wave signal intensity in the space. The lower the frequency, the smaller the energy loss of the radio wave mainly concentrated in the propagation of the metal conductor, and the energy propagated in the medium is relatively large, so it is mainly concentrated in the conductor. Based on this, the core of the secondary cable is a good solid conductor, and the work needs to detect the consistency of the core, so it should ensure that the energy of its radio frequency signal flows on the conductor surface of the antenna, and the signal radiated to the surrounding space is as small as possible, and the wireless signal intensity induced by the metal conductor is smaller. Therefore, it is necessary to use a low-frequency signal. In this way, the intensity of the radio frequency signal in the non-detection core and the detection core will be significantly different.

[0044] According to electromagnetic theory, the calculation formula of antenna length and frequency is:

[0045] Where c is the speed of light and f is the frequency. Considering that the longest cable length of the substation is less than 2km, the highest frequency of the transmitted signal is calculated as:

[0046] f = 37.5kHz. Considering a certain margin, the highest frequency of the transmitted signal is 30kHz, which can ensure that its electromagnetic energy is mainly concentrated in the conductor and not radiated to the surrounding space.

[0047] Calculation of host transmission power:

[0048] The calculation method of antenna transmission power is as follows:

[0049] The DC resistance calculation formula of metal conductor is: Among them, ρ is resistivity, L is length, and S is conductor cross section. According to the calculation formula of DC resistance, the resistance of a copper core cable with a length of 1 square millimeter and a length of 1 meter at 20 degrees Celsius is 0.0185 ohms. Therefore, considering that the longest substation cable is calculated as 2000 meters and the smallest area is calculated as 1.5mm2, the maximum resistance of the substation cable core is 24.6 ohms.

[0050] Assuming the RF signal voltage is 3V, its loss is: The converted loss is: P = 25.6dbm. The requirement of retaining a margin of 1.5 is 38.4dbm. Therefore, the transmission power is selected as 40dbm, which retains enough margin to fully meet the attenuation of the cable core to the signal and ensure sufficient signal strength at the receiving end. Determination of the transmission frequency f:

[0051] It has been determined that the highest frequency of the transmitted signal is 30kHz. But in fact, the frequency not only affects the attenuation of the intensity, but also the scattering of the signal in the surrounding space and the sensitivity of the receiving instrument at the receiving end. Through experimental analysis, under the premise of ensuring the best receiving effect and detection accuracy at the receiving end, the parameter values ​​of the cable core length and the transmitting frequency are determined as shown in Table 1.

[0052] Table 1 Correspondence between cable length and transmission frequency

[0053] Length (m) 50< 50-400 400-800 8000-1300 1300-1800 >1800 Frequency (kHz) 25 22.5 19.5 17.5 19.5 23.5

[0054] According to the conclusions shown in Table 1, a local oscillation module can be set in the hardware design, and its oscillation frequency can be set to 15kHz.

[0055] Circuit structure design of detector:

[0056] The host includes a transmitting antenna, a tuner, a mixer, a local oscillator module, an oscillation module, a main control module, a data communication module, a human-machine interface module, and a wireless communication module. The hardware structure diagram is shown below: Figure 2 shown.

[0057] The working process is as follows: After the detector is powered on, it first completes the data communication self-check with the slave machine. After the data communication is normal, it starts to enter the working state. The local oscillator module generates a sine wave signal with a frequency of f0 and an intensity of -5dbm. After the human-machine module sets the input of the approximate core wire length L, the main control CPU obtains the corresponding frequency parameter A according to Table 1, and inputs the numerical value A into the oscillation module. Then the value A is sent to the slave machine. After the slave machine responds, the host waits for the slave machine test completion signal. After the main control CPU receives the detection success logic signal from the slave machine, it controls the local oscillator module and the oscillation module to stop outputting signals and sends the slave machine response information.

[0058] The host oscillation module is used to generate a frequency f corresponding to the value A. A The sine wave signal is sent to the mixer, and the mixer outputs a frequency of f = f0 + f A , 200mv amplitude, power of -5dbm, amplitude of 3v sine wave signal to the tuner, the tuner outputs a sine wave signal with frequency f and strength of 40dbm to the antenna. The host sends the value A to the slave through the wireless communication module. After that, the tuner continues to send a sine wave signal with frequency f, strength of 40dbm and amplitude of 3v.

[0059] like Figure 3 As shown, the slave is the same as the host, including a receiving antenna, a filtering module, a detector, a main control module, a data communication module, a wireless communication module and a human-machine interface module.

[0060] The working process is as follows: After the slave is powered on, it first completes the data communication status self-check procedure with the host, and then enters the working state after the communication is normal. A If the value is received normally, a prompt message will be sent to the human-machine module, and the filter's frequency band will be controlled to be f. At this time, the detector is always listening to the electromagnetic wave information output by the filter. When the signal strength>10dbm signal is detected, the logic instruction of receiving the signal will be sent to the main control CPU. After receiving the logic instruction of the detector, the main control CPU will send information to the human-machine interface, and send the detection success logic information to the data communication module, waiting for the host to respond.

[0061] The host software process is as follows:

[0062] After the device is powered on, it completes parameter self-check and initialization, and then starts to establish a communication connection with the slave. After the data communication with the slave is normal within a certain time, the local oscillator module is controlled to send a local oscillator signal. After an abnormality, it is processed according to interrupt procedure 1. Then wait for the human-machine module to input the parameter information of the cable core length, and obtain the frequency f according to the parameter information. A and sends it to the oscillation module and the data communication module; then, within a certain period of time, it is determined whether the slave has received f AIf there is data, it will enter interrupt program 2, if not, it will enter interrupt program 1; after interrupt program 2 is executed, it will send f to the oscillation module A After that, poll and wait for the data detection information of the slave; if the transmission success information is received, the command to stop working is sent to the oscillator module and the local oscillator module, otherwise, it is processed according to the invisible abnormal situation detected; the interrupt 1 generated by the host program has two aspects, one is when establishing data communication status with the slave, the abnormal setting flag 1, and the second is the slave receiving the host f A response; after the response times out, flag 2 is set and interrupt 1 is generated. After the interrupt 1 program is executed, the abnormal working situation is handled according to flag 1 and flag 2, and an abnormal information prompt is sent to the human-machine interface module.

[0063] The slave software process is as follows:

[0064] After the device is powered on, it completes parameter self-check and initialization, and then starts to establish a communication connection with the host. After the data communication with the host is normal within a certain time, wait for the host to send f A ; After the exception, set the flag 1 and generate an interrupt; receive f within a certain time A After that, it is sent to the filtering module, and a prompt detection message is sent to the human-machine interface module; after that, the main control program constantly loops to detect whether the detector has a signal output. If so, the detection success logic information is sent to the host, and a prompt message is sent to the human-machine interface; if not, it is determined whether there is manual operation on the abnormal situation. If so, flag 2 is set and an interrupt is generated; the interrupt program completes the exception handling, determines flag 1, and completes the exception handling of the communication failure with the host; flag 2 detects the occurrence of invisible abnormal conditions to the host and completes the exception handling.

[0065] The present invention avoids the disadvantages of low efficiency and high false detection rate in the current detection of secondary circuits of substations by using a multimeter in combination with the equipment ground network for test wiring to form a connection circuit for detection. Through actual on-site detection, the efficiency of the detector of the present invention is improved by more than 40%, and the false detection rate is 0.

[0066] Example 2

[0067] In a 500Kv line protection replacement in a 500kV substation, 28 cables need to be checked, involving 239 secondary cores. All tests were completed in 4.5 hours. In the past, in a 500Kv line protection replacement, the second-line loop calibration work required a day's work, which took an average of 8 hours. After using the detector of the present invention, the work can be completed in half a working day. This shows that the use of the detector of the present invention has a significant effect. No false detection occurred during the use of the instrument.

[0068] Example 3

[0069] Two identical representative secondary cables were selected for testing in a newly built 220Kv interval of a 500Kv substation. One of them was tested using the existing multimeter method, and the average time for each secondary core was 5 minutes. The other was tested using the detector of the present invention, and the average time for each secondary core was 2 minutes. The average time for each core was shortened by more than half, which shows that the efficiency of using the detector of the present invention is significantly improved. No false detection occurred during the use of the instrument.

Claims

1. A wireless secondary circuit intelligent detector, It is characterized in that It comprises a host and a slave, wherein the host comprises a transmitting antenna, a tuner, a mixer, a local oscillator module, an oscillation module, a main control module, a data communication module, a human-machine interface and a wireless communication module; the main control module communicates data information with the human-machine interface, the oscillation module, the local oscillator module and the data communication module, wherein two-way data communication is performed with the human-machine interface and the data communication module, the human-machine interface and the data communication module receive data and command information sent by the main control module, and transmit various data back to the main control module at the same time; the local oscillator module and the oscillation module receive control command information from the main control module and complete corresponding operations; the mixer mixes and superimposes different frequency signals generated by the local oscillator module and the oscillation module, and then sends the signal to the tuner, and the tuner modulates and amplifies the signal strength to a set signal strength and then transmits the high-frequency electromagnetic signal through the transmitting antenna; The data communication module receives the data and control information of the master control module, and exchanges the data information with the slave through the wireless communication module; The working process of the host is as follows: after the instrument is powered on, it first completes the data communication self-check with the slave. After the data communication is normal, it starts to enter the working state; the local oscillator module generates a frequency of f 0 , a sine wave signal with a strength of -5dbm. After the human-machine interface sets the input core length L, the main control CPU obtains the corresponding frequency parameter A and inputs the numerical value A into the oscillation module; then the numerical value A is sent to the slave. After the slave responds, the host waits for the slave test completion signal; after the main control CPU receives the detection success logic signal from the slave, it controls the local oscillator module and the oscillation module to stop outputting signals and sends the slave response information; The host oscillation module is used to generate a frequency f corresponding to the value A. A The sine wave signal is sent to the mixer, and the mixer outputs a frequency of f=f 0 +f A , 200mv amplitude, a sine wave signal with a power of -5dbm and an amplitude of 3v is sent to the tuner, and the tuner outputs a sine wave signal with a frequency of f and an intensity of 40dbm to the antenna; the host sends the value A to the slave through the wireless communication module; thereafter, the tuner continues to send a sine wave signal with a frequency of f, an intensity of 40dbm and an amplitude of 3v.

2. A wireless secondary circuit intelligent detector according to claim 1, It is characterized in that The slave includes a receiving antenna, a filtering module, a detector, a main control module, a data communication module, a wireless communication module and a human-machine interface; The main control module communicates data information with the data communication module, the human-machine interface, the filter module, and the detector. The main control module communicates data with the human-machine interface module and the data communication module in a two-way manner. The human-machine interface module and the data communication module receive data information sent by the main control module. The main control module sends the electromagnetic signal of the frequency that needs to be passed to the detector to the filter module. The detector determines whether the filter module sends an electromagnetic signal of a certain intensity and sends the result to the main control module. The data communication module receives the data and control information of the main control module, and exchanges the data information with the host through the wireless communication module; The host and the slave communicate wirelessly via a wireless communication module.

3. A wireless secondary circuit intelligent detector according to claim 1, It is characterized in that The slave working process is as follows: after the slave is powered on, it first completes the data communication status self-check program with the host, and then enters the working state after the communication is normal; it continues to wait for the f sent by the host. A If the value is received normally, a prompt message will be sent to the human-machine interface module, and the filter's frequency band will be controlled to be f; at this time, the detector will always monitor the electromagnetic wave information output by the filter module; when the signal strength>10dbm signal is detected, the logic instruction of receiving the signal will be sent to the main control CPU; after receiving the logic instruction of the detector, the main control CPU will send information to the human-machine interface, and send the detection success logic information to the data communication module, waiting for the host to respond.

4. A wireless secondary circuit intelligent detector according to claim 1, It is characterized in that The host software process is as follows: After the device is powered on, it completes parameter self-check and initialization, and then starts to establish a communication connection with the slave. After the data communication with the slave is normal within a certain time, the local oscillator module is controlled to send a local oscillator signal. After an abnormality, it is processed according to interrupt procedure 1. Then wait for the human-machine module to input the parameter information of the cable core length, and obtain the frequency f according to the parameter information. A and sends it to the oscillation module and the data communication module; then, within a certain period of time, it is determined whether the slave has received f A If there is data, it will enter interrupt program 2, if not, it will enter interrupt program 1; after interrupt program 2 is executed, it will send f to the oscillation module A After that, poll and wait for the data detection information of the slave; if the transmission success information is received, the command to stop working is sent to the oscillator module and the local oscillator module, otherwise, it is processed according to the invisible abnormal situation detected; the interrupt 1 generated by the host program has two aspects, one is when establishing data communication status with the slave, the abnormal setting flag 1, and the second is the slave receiving the host f A response; after the response times out, flag 2 is set, interrupt 1 is generated, and after the interrupt 1 program is executed, the abnormal working situation is handled according to flag 1 and flag 2, and an abnormal information prompt is sent to the human-machine interface module.

5. A wireless secondary circuit intelligent detector according to claim 1, It is characterized in that The slave software process is as follows: After the device is powered on, it completes parameter self-check and initialization, and then starts to establish a communication connection with the host. After the data communication with the host is normal within a certain time, it waits for the host to send f A ; After the exception, set the flag 1 and generate an interrupt; receive f within a certain time A After that, it is sent to the filtering module, and a prompt detection message is sent to the human-machine interface module; after that, the main control program constantly loops to detect whether the detector has a signal output. If so, the detection success logic information is sent to the host, and a prompt message is sent to the human-machine interface; if not, it is determined whether there is manual operation on the abnormal situation. If so, flag 2 is set and an interrupt is generated; the interrupt program completes the exception handling, determines flag 1, and completes the exception handling of the communication failure with the host; flag 2 detects the occurrence of invisible abnormal conditions to the host and completes the exception handling.

6. The detection method of a wireless secondary circuit intelligent detector according to claim 1, It is characterized in that Radio frequency technology is adopted, and the secondary core to be checked is used as a transmitting antenna of radio frequency signal; the host is used on one side of the tested core, responsible for generating radio frequency signal, injecting the signal into the core and transmitting it; the slave is used on the other side of the tested core, and determines whether the host and the slave are connected to the same core by detecting the difference in the radio frequency signal strength of the tested core and the non-tested core, thereby achieving the purpose of secondary circuit detection, and the host and the slave communicate data through wireless signals.

7. The detection method of a wireless secondary circuit intelligent detector according to claim 1, It is characterized in that The calculation formula of antenna length and frequency is: , where c is the speed of light and f is the frequency.

8. The detection method of a wireless secondary circuit intelligent detector according to claim 1, It is characterized in that The longest cable length of the substation is less than 2km, and the highest frequency of the transmitted signal is calculated to be: ,Considering the margin, the highest frequency of the transmitted signal is 30kHz.

9. The detection method of a wireless secondary circuit intelligent detector according to claim 1, It is characterized in that The parameter value relationship between the cable core length and the transmission frequency is as follows: when the length is less than 50 meters, the frequency is 25 kHz; when the length is 50-400 meters, the frequency is 22.5 kHz; when the length is 400-800 meters, the frequency is 19.5 kHz; when the length is 800-1300 meters, the frequency is 17.5 kHz; when the length is 1300-1800 meters, the frequency is 19.5 kHz; when the length is greater than 1800 meters, the frequency is 23.5 kHz.

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