Transmission tower grounding resistance on-line monitoring device

Abstract

The utility model provides a transmission tower grounding resistance on-line monitoring device used for on-line monitoring grounding resistance, the device comprises a monitoring unit and a power supply unit, the monitoring unit comprises a main control module, a program control AC current source, a first surge protection module, a second surge protection module, a pre-amplifier, a filter and an AD converter. The on-line monitoring device provided by the utility model can realize the on-line measurement of the grounding resistance of the power transmission tower, the whole measurement process is real-time and on-line monitored without manual operation, the number of the grounding resistance is automatically measured, and the measurement data is automatically uploaded in real time. Therefore, the problems of time and labor waste and low detection efficiency of the grounding resistance detection of the power transmission tower caused by the off-line test at present are solved.

Description

Technical Field

[0001] The utility model relates to the field of electronic measurement, and more specifically to an online monitoring device for grounding resistance of a power transmission tower. Background Art

[0002] The grounding device of the transmission tower is an important part of the transmission line. It is also the general term for the grounding body and the grounding down conductor. The grounding resistance refers to the sum of the grounding body's scattered current resistance, the grounding down conductor resistance and the contact resistance. Its function is to conduct lightning current into the ground to ensure that the line has a certain level of lightning resistance, ensure that the lightning current is reliably discharged into the earth, protect the line equipment, reduce the risk of line lightning tripping, and improve the stability of the transmission line.

[0003] The main indicator for evaluating the performance of the transmission tower grounding device is the grounding resistance. The smaller the grounding resistance, the higher the lightning resistance level of the transmission tower grounding device. The larger the grounding resistance, the lower the lightning resistance level of the transmission tower grounding device. Therefore, in order to ensure the reliability of the operation of the transmission tower grounding device, it is necessary to measure the tower grounding resistance value regularly to ensure the normal operation of the transmission line.

[0004] The current method for measuring the grounding resistance of transmission towers is an offline test, which requires inspection personnel to carry equipment to the towers to be tested. The test cycle of this test method is long, and the test data cannot be uploaded in real time. According to the relevant standards of the power industry, the grounding resistance of transmission towers needs to be tested regularly. The grounding resistance detection cycle of transmission towers in areas with high lightning strikes is once every 5 years, and the grounding resistance detection cycle of transmission towers in areas with high lightning strikes is once every 2-3 years. The grounding resistance detection cycle of transmission towers in the 3km section of the substation, the 3km section of the converter station and special locations is once a year. At the same time, since most transmission towers are erected in suburban areas or even mountainous areas, it can be seen that the current offline test makes the grounding resistance detection of transmission towers time-consuming and labor-intensive, and the detection efficiency is low. Summary of the invention

[0005] The utility model aims at the technical problems existing in the prior art and provides an online monitoring device for the grounding resistance of a transmission tower, comprising a monitoring unit and a power supply unit, wherein the monitoring unit comprises a main control module, a programmable alternating current source, a first surge protection module, a second surge protection module, a preamplifier, a filter and an AD converter, wherein the output end of the main control module is connected to the input end of the programmable alternating current source, the output end of the programmable alternating current source is connected to the input end of the first surge protection module, the output end of the second surge protection module is connected to the input end of the preamplifier, the output end of the preamplifier is connected to the input end of the filter, the output end of the filter is connected to the input end of the AD converter, the output end of the AD converter is connected to the input end of the main control module, the output end of the first surge protection module is connected to the earth by a current signal line, and the input end of the second surge protection module is connected to the earth by a voltage signal line;

[0006] The power supply unit includes a photovoltaic panel, a power management module and a lithium battery. The photovoltaic panel is connected to the power management module, the power management module is connected to the lithium battery, and the power management module is connected to each module in the monitoring unit to provide power to each module.

[0007] The utility model provides an online monitoring device for the grounding resistance of a transmission tower, which can realize the online measurement of the grounding resistance of the transmission tower. The entire measurement process is monitored online in real time without manual operation, the grounding resistance digital is automatically measured, and the measurement data is automatically uploaded in real time, thereby solving the problem that the current offline test makes the grounding resistance detection of the transmission tower time-consuming and labor-intensive, and the detection efficiency is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 A schematic diagram of the structure of an online monitoring device for grounding resistance of a transmission tower provided by the utility model;

[0009] Figure 2 This is a schematic diagram of the installation and measurement of the online monitoring device for the grounding resistance of the transmission tower;

[0010] Figure 3 A schematic diagram of circuit connection between a programmable AC current source and a first surge protection module;

[0011] Figure 4 This is a circuit connection diagram of the preamplifier and the second surge protection module. DETAILED DESCRIPTION

[0012] In order to make the purpose, technical scheme and advantages of the embodiment of the utility model clearer, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the utility model. In addition, the technical features in each embodiment or a single embodiment provided by the utility model can be combined with each other arbitrarily to form a feasible technical solution. This combination is not subject to the constraints of the sequence of steps and / or the structural composition mode, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that this combination of technical solutions does not exist and is not within the scope of protection required by the utility model.

[0013] Figure 1 The utility model provides an online monitoring device for the grounding resistance of a transmission tower. Figure 2 As shown, the monitoring device is connected to both ends of the grounding device of the transmission tower and is used to monitor the grounding resistance of the grounding device online. Figure 1 As shown, the device includes a monitoring unit and a power supply unit, the monitoring unit includes a main control module, a programmable AC current source, a first surge protection module, a second surge protection module, a preamplifier, a filter and an AD converter, the output end of the main control module is connected to the input end of the programmable AC current source, the output end of the programmable AC current source is connected to the input end of the first surge protection module, the output end of the second surge protection module is connected to the input end of the preamplifier, the output end of the preamplifier is connected to the input end of the filter, the output end of the filter is connected to the input end of the AD converter, the output end of the AD converter is connected to the input end of the main control module, the output end of the first surge protection module is connected to the ground using a current signal line, and the input end of the second surge protection module is connected to the ground using a voltage signal line.

[0014] The power supply unit includes a photovoltaic panel, a power management module and a lithium battery. The photovoltaic panel is connected to the power management module, the power management module is connected to the lithium battery, and the power management module is connected to each module in the monitoring unit to provide power to each module.

[0015] like Figure 3As shown, in some embodiments, the programmable AC current source includes resistors R11 to R20, operational amplifier U6, operational amplifier U7, power switch tube Q3 and power switch tube Q4, the in-phase input terminal of the operational amplifier U6 is connected in series with resistor R14, and the in-phase input terminal of the operational amplifier U7 is connected in series with resistor R16 as the input terminal of the programmable AC current source connected to the output terminal of the main control module, the inverting input terminal of the operational amplifier U6 is connected in series with resistor R15, and the inverting input terminal of the operational amplifier U7 is connected in series with resistor R17, respectively, and is grounded, the in-phase input terminal of the operational amplifier U6 is connected in series with resistor R13 to the positive power supply, and the in-phase input terminal of the operational amplifier U7 is connected in series with resistor R18 to the positive power supply Negative power supply, the output end of the operational amplifier U6 is connected to the control end of the power switch tube Q3, the output end of the operational amplifier U7 is connected to the control end of the power switch tube Q4, the power switch tube Q3 and the power switch tube Q4 are connected in series, the input end of the power switch tube Q3 is connected in series with resistor R11 and then connected to the positive power supply, the input end of the power switch tube Q3 is connected in series with resistor R12 and then connected to the inverting input end of the operational amplifier U6, the output end of the power switch tube Q4 is connected in series with resistor R20 and then connected to the negative power supply, the output end of the power switch tube Q4 is connected in series with resistor R19 and then connected to the inverting input end of the operational amplifier U7, and the common end of the power switch tube Q3 and the power switch tube Q4 serves as the output end of the programmable AC source circuit.

[0016] A current source circuit is formed by resistors R11 to R20, power switch tube Q3, power switch tube Q4, operational amplifier U6 and operational amplifier U7, which is used to convert the voltage signal output by the main control module into a large current signal for direct output to the first surge protection module.

[0017] Wherein, the first surge protection module includes a first current limiting resistor R21, a second current limiting resistor R22, a first transient suppression diode D1 and a first varistor RV1, the two ends of the first varistor RV1 are respectively connected to one end of the first current limiting resistor R21 and one end of the second current limiting resistor R22, the two ends of the first transient suppression diode D1 are respectively connected to the other end of the first current limiting resistor R21 and the other end of the second current limiting resistor R22, the common end connected to the first varistor RV1 and the first current limiting resistor R21 is connected to the programmable AC current source as an input end, the common end connected to the first varistor RV1 and the second current limiting resistor R22 is grounded, the common end connected to the first transient suppression diode D1 and the first current limiting resistor R21 is connected to the ground using a current signal line, and the common end connected to the first transient suppression diode D1 and the second current limiting resistor R22 is used to connect to a grounding device. Wherein, the transmission tower grounding resistance online monitoring device provided by the utility model is connected to a grounding device to measure the grounding resistance of the grounding device

[0018] It should be noted that the rated voltage of the first varistor RV1 is V1, the rated voltage of the first transient suppression diode D1 is V2, and the rated voltage V2 is less than the rated voltage V1. When a surge voltage is input to the input port, and the input port voltage exceeds the rated voltage V1 of the first varistor RV1, the first varistor RV1 starts the voltage clamping protection, and clamps the port voltage of the first varistor RV1 to the rated voltage V1. At the same time, the rated voltage V1 passes through the first current limiting resistor and the second current limiting resistor, and is further clamped by the first transient suppression diode D1, so that the output voltage is clamped to V2. The voltage of V2 is relatively low, thereby protecting against surge voltage.

[0019] like Figure 4 As shown, the second surge protection module includes a third current limiting resistor R31 and a fourth current limiting resistor R32, a second transient suppression diode D2 and a second varistor RV2, two ends of the second varistor RV2 are respectively connected to one end of the third current limiting resistor R31 and one end of the fourth current limiting resistor R32, two ends of the second transient suppression diode D2 are respectively connected to the other end of the third current limiting resistor R31 and the other end of the fourth current limiting resistor R32, a common end of the second varistor RV2 connected to the third current limiting resistor R31 is connected to the preamplifier as an input end, a common end of the second varistor RV2 connected to the fourth current limiting resistor R32 is grounded, a common end of the second transient suppression diode D2 connected to the third current limiting resistor R31 is used to connect to a grounding device, and a common end of the second transient suppression diode D2 connected to the fourth current limiting resistor R32 is connected to the ground using a current signal line.

[0020] When a surge voltage is input to the input port, and the input port voltage exceeds the rated voltage V1 of the second varistor RV2, the second varistor RV2 starts the voltage clamping protection, and clamps the port voltage of the second varistor RV2 to the rated voltage V1. At the same time, the rated voltage V1 passes through the third current limiting resistor and the fourth current limiting resistor, and is further clamped by the second transient suppression diode D2, so that the output voltage is clamped to V2, and the voltage of V2 is relatively low, thereby protecting against surge voltage.

[0021] See also Figure 1 In some embodiments, the device further includes a control unit, which includes a GPS module, a NBIoT module, and a test button, and the GPS module, the NBIoT module, and the test button are all connected to the input end of the main control module. The GPS module is used to collect positioning information and time information, and send the collected information to the main control module, the NBIoT module is used to issue instructions to the main control module through networking, and the test button is used to issue instructions to the main control module by manually pressing the test button.

[0022] The working principle of the online monitoring device for the grounding resistance of a power transmission tower of the utility model is as follows: the photovoltaic panel receives sunlight and converts solar energy into a DC voltage, and the power management module converts the DC voltage into a charging voltage to charge the lithium battery. When the device is in a test state, the power management module can convert the battery voltage into the power supply voltage required by each module in the monitoring unit. When the online monitoring device for the grounding resistance of a power transmission tower in sleep mode receives a test instruction sent by the NBIoT module, or the test button is pressed manually, the main control module enters the grounding resistance measurement state of the power transmission tower, and the main control module controls the programmable AC current source to output an AC test current, and the test current flows to the grounding device under test after passing through the first surge protection module. The first surge protection module is used to suppress surge current and voltage when the power transmission tower is struck by lightning, so as to prevent the device from being damaged by lightning. After the test current flows through the grounding device under test, a voltage signal is generated. At this time, the test voltage is clamped by the second surge protection module, and then the voltage signal is amplified by the preamplifier. Then, the noise signal in the voltage signal is filtered out by the filter, and then the filtered voltage signal is converted into a digital signal by the AD converter. The main control module analyzes the digital signal to calculate the test voltage. At the same time, according to Ohm's law, the voltage signal is divided by the current signal to obtain the grounding resistance. At this time, the positioning information and time information are sent to the main control module through the GPS module. After the main control module collects the time information, positioning information, and measured resistance value, it packages the data and sends it to the background server through the NBIoT module. Then the device enters the sleep mode and waits for the next wake-up. Finally, the online measurement of the grounding resistance of the transmission tower grounding resistance online monitoring device is realized. The entire measurement process is monitored online in real time without manual operation, and the grounding resistance digital is automatically measured, and the measurement data is automatically uploaded in real time, thereby solving the problem that the current offline test makes the transmission tower grounding resistance detection time-consuming and labor-intensive, and the detection efficiency is low.

[0023] The utility model provides an online monitoring device for the grounding resistance of a transmission tower, which can realize the online measurement of the grounding resistance of the transmission tower. The entire measurement process is monitored online in real time without manual operation, the grounding resistance digital is automatically measured, and the measurement data is automatically uploaded in real time, thereby solving the problem that the current offline test makes the grounding resistance detection of the transmission tower time-consuming and labor-intensive, and the detection efficiency is low.

[0024] It should be noted that in the above embodiments, the description of each embodiment has its own emphasis, and for parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0025] Although the preferred embodiments of the utility model have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the utility model.

[0026] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A transmission tower grounding resistance online monitoring device, used for online monitoring of grounding resistance, characterized in that: The device comprises a monitoring unit and a power supply unit, wherein the monitoring unit comprises a main control module, a programmable AC current source, a first surge protection module, a second surge protection module, a preamplifier, a filter and an AD converter, wherein the output end of the main control module is connected to the input end of the programmable AC current source, the output end of the programmable AC current source is connected to the input end of the first surge protection module, the output end of the second surge protection module is connected to the input end of the preamplifier, the output end of the preamplifier is connected to the input end of the filter, the output end of the filter is connected to the input end of the AD converter, the output end of the AD converter is connected to the input end of the main control module, the output end of the first surge protection module is connected to the ground using a current signal line, and the input end of the second surge protection module is connected to the ground using a voltage signal line; The power supply unit includes a photovoltaic panel, a power management module and a lithium battery. The photovoltaic panel is connected to the power management module, the power management module is connected to the lithium battery, and the power management module is connected to each module in the monitoring unit to provide power to each module.

2. The transmission tower grounding resistance online monitoring device according to claim 1, characterized in that: The programmable AC current source includes resistors R11 to R20, operational amplifier U6, operational amplifier U7, power switch tube Q3 and power switch tube Q4. The in-phase input terminal of operational amplifier U6 is connected in series with resistor R14, and the in-phase input terminal of operational amplifier U7 is connected in series with resistor R16 as the input terminal of the programmable AC current source to the output terminal of the main control module. The inverting input terminal of operational amplifier U6 is connected in series with resistor R15, and the inverting input terminal of operational amplifier U7 is connected in series with resistor R17, respectively, and is grounded. The in-phase input terminal of operational amplifier U6 is connected in series with resistor R13 to the positive power supply, and the in-phase input terminal of operational amplifier U7 is connected in series with resistor R18 to the negative power supply. The output end of amplifier U6 is connected to the control end of power switch tube Q3, the output end of operational amplifier U7 is connected to the control end of power switch tube Q4, power switch tube Q3 is connected in series with power switch tube Q4, the input end of power switch tube Q3 is connected in series with resistor R11 and then connected to the positive power supply, the input end of power switch tube Q3 is connected in series with resistor R12 and then connected to the inverting input end of operational amplifier U6, the output end of power switch tube Q4 is connected in series with resistor R20 and then connected to the negative power supply, the output end of power switch tube Q4 is connected in series with resistor R19 and then connected to the inverting input end of operational amplifier U7, and the common end of power switch tube Q3 and power switch tube Q4 serves as the output end of program-controlled AC source circuit; A current source circuit is formed by resistors R11 to R20, power switch tube Q3, power switch tube Q4, operational amplifier U6 and operational amplifier U7, which is used to convert the voltage signal output by the main control module into a large current signal for direct output to the first surge protection module.

3. The transmission tower grounding resistance online monitoring device according to claim 2 is characterized in that: The first surge protection module includes a first current limiting resistor, a second current limiting resistor, a first transient suppression diode D1 and a first varistor RV1, the two ends of the first varistor RV1 are respectively connected to one end of the first current limiting resistor and one end of the second current limiting resistor, the two ends of the first transient suppression diode D1 are respectively connected to the other end of the first current limiting resistor and the other end of the second current limiting resistor, the common end of the first varistor RV1 connected to the first current limiting resistor is connected to the programmable AC current source as an input end, the common end of the first varistor RV1 connected to the second current limiting resistor is grounded, the common end of the first transient suppression diode D1 connected to the first current limiting resistor is connected to the ground using a current signal line, and the common end of the first transient suppression diode D1 connected to the second current limiting resistor is used to connect a grounding device.

4. The transmission tower grounding resistance online monitoring device according to claim 3 is characterized in that: The rated voltage of the first varistor RV1 is V1, the rated voltage of the first transient suppression diode D1 is V2, and the rated voltage V2 is less than the rated voltage V1.

5. The transmission tower grounding resistance online monitoring device according to claim 2, characterized in that: The second surge protection module includes a third current limiting resistor and a fourth current limiting resistor, a second transient suppression diode D2 and a second varistor RV2, the two ends of the second varistor RV2 are respectively connected to one end of the third current limiting resistor and one end of the fourth current limiting resistor, the two ends of the second transient suppression diode D2 are respectively connected to the other end of the third current limiting resistor and the other end of the fourth current limiting resistor, the common end of the second varistor RV2 connected to the third current limiting resistor is connected to the preamplifier as an input end, the common end of the second varistor RV2 connected to the fourth current limiting resistor is grounded, the common end of the second transient suppression diode D2 connected to the third current limiting resistor is used to connect to a grounding device, and the common end of the second transient suppression diode D2 connected to the fourth current limiting resistor is connected to the ground using a current signal line.

6. The transmission tower grounding resistance online monitoring device according to claim 5, characterized in that: The rated voltage of the second varistor RV2 is V1, the rated voltage of the second transient suppression diode D2 is V2, and the rated voltage V2 is less than the rated voltage V1.

7. The transmission tower grounding resistance online monitoring device according to claim 1, characterized in that: The device also includes a control unit, which includes a GPS module, a NBIoT module and a test button. The GPS module, the NBIoT module and the test button are all connected to the input end of the main control module. The GPS module is used to collect positioning information and time information, and send the collected positioning information and time information to the main control module. The NBIoT module is used to issue instructions to the main control module via networking, and the test button is used to issue instructions to the main control module by manually pressing the test button.

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