Grounding down lead conduction resistance tester

Abstract

The utility model discloses a grounding down lead conduction resistance tester, which belongs to electric power facility measuring equipment and comprises a main control module, the main control module is respectively connected with a voltage measuring module and a current measuring module, and the voltage measuring module is provided with a voltage sampling circuit; the current measurement module is provided with a current sampling circuit; the main control module is further connected with a PWM control circuit, the PWM control circuit is connected with a constant current circuit, the constant current circuit is connected with a constant current output circuit, the constant current output circuit is connected with a protection circuit, and the protection circuit is connected with an acquisition end. The main control module adjusts and controls constant current output through pulse width, and synchronously measures the resistance condition of the current acquisition end through the voltage measurement module and the current measurement module, thereby achieving a high-precision and high-stability measurement effect and a highly automatic measurement function. The device has the characteristics of large output current, high precision, wide measuring range, stable data, good repeatability, strong anti-interference capability, perfect protection function, high charging and discharging speed and the like.

Description

Technical Field

[0001] This utility model relates to a power facility measuring device, and more specifically, it relates to a grounding lead continuity resistance tester. Background Technology

[0002] A grounding down conductor continuity resistance tester is a specialized instrument used to measure the resistance of the connecting conductor between various electrical equipment and the grounding grid. A reliable and effective connection between the grounding down conductor of power equipment and the grounding grid is fundamental to the safe operation of the equipment. According to the power industry standard DL / T475-2006 "Guidelines for Measurement of Characteristic Parameters of Grounding Devices," electrical continuity should be measured using specialized instruments with a resolution not exceeding 1 mΩ and an accuracy not lower than class 1.0. However, most existing testing instruments fail to meet the requirements of the aforementioned standard, or the measurement results are unstable during use. Therefore, it is necessary to further study and improve the circuit structure of such measuring instruments. Utility Model Content

[0003] One of the objectives of this utility model is to address the aforementioned shortcomings by providing a grounding lead continuity resistance tester, which aims to solve the technical problems of existing measuring instruments failing to meet the requirements of the standards in the background art, or having unstable measuring structures.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] This utility model provides a grounding lead continuity resistance tester, comprising a main control module, which is connected to a voltage measurement module and a current measurement module. The voltage measurement module has a voltage sampling circuit, which is used to connect to the acquisition terminal. The current measurement module has a current sampling circuit, which is used to connect to the acquisition terminal. The main control module is also connected to a PWM control circuit, which is connected to a constant current circuit. The constant current circuit is connected to a constant current output circuit, which is connected to a protection circuit. The protection circuit is used to obtain output feedback from the constant current output circuit and adjust the output current. The protection circuit is also connected to a freewheeling discharge circuit, which is also used to connect to the acquisition terminal. The protection circuit is grounded.

[0006] A further technical solution is that the current sampling circuit further includes a first signal amplification circuit, which is connected to the main control module. The first signal amplification circuit is also connected to a first filter circuit, which is connected to the voltage sampling circuit.

[0007] A further technical solution is that the voltage sampling circuit further includes a second signal amplification circuit, which is connected to the main control module, and also to a second filter circuit. The second filter circuit is also connected to a differential circuit, which is connected to the current sampling circuit.

[0008] A further technical solution is that the main control module is also connected to a wireless communication module, a Bluetooth module, a USB communication module, and an LCD screen.

[0009] Compared with the prior art, one of the beneficial effects of this utility model is that the main control module controls the constant current output through pulse width adjustment, and synchronously measures the resistance of the current acquisition terminal through the voltage measurement module and the current measurement module, achieving high precision, high stability measurement effect and highly automated measurement function. It has the characteristics of large output current, high precision, wide range, stable data, good repeatability, strong anti-interference ability, perfect protection function, and fast charging and discharging speed. Attached Figure Description

[0010] Figure 1 This is a schematic circuit diagram illustrating one embodiment of the present invention. Detailed Implementation

[0011] The present invention will be further described below with reference to the accompanying drawings.

[0012] refer to Figure 1 As shown in the figure, one embodiment of this utility model is a grounding lead continuity resistance tester. As shown in the figure, the grounding lead continuity resistance tester includes a power supply circuit, a PWM control circuit, a constant current circuit, a constant current output circuit, an output feedback circuit, a freewheeling discharge circuit, a protection circuit, a voltage measurement module, a current measurement module, and other peripheral circuits (wireless communication module, Bluetooth module, and USB communication module).

[0013] The aforementioned power supply circuit provides regulated power to all circuits. By using chips such as relays, optocouplers, and Zener diodes, it achieves operations such as switching between lithium battery and 220V AC mains power, and isolating the power supply from the main control module. At the same time, it provides different voltage regulation circuits to power various parts of the overall circuit, improving power quality and power output.

[0014] The aforementioned PWM control circuit uses the PWM signal output provided by the main control module to control the constant current output.

[0015] The constant current circuit described above is based on the power supply topology designed with the 494 chip. It uses PWM for output control and, in conjunction with a current feedback circuit, can provide a maximum constant current output of 10A.

[0016] The aforementioned constant current output circuit provides a current output control interface, enabling hardware control to stabilize the output current.

[0017] The aforementioned freewheeling discharge circuit provides a discharge loop after the test, enabling automatic discharge and allowing the tested object or circuit to be safely disconnected.

[0018] The aforementioned current measurement module acquires the measured current via differential input, converts it into a voltage signal, filters and amplifies it, and then outputs it to a high-precision AD chip for sampling. It also includes a zero-adjustment circuit for adjusting the offset of small currents.

[0019] The voltage measurement module described above collects the voltage signal across the resistor, filters and amplifies it, and then outputs it to a high-precision AD chip for voltage sampling.

[0020] The aforementioned protection circuit has circuit protection functions, including external voltage input protection, overload output protection, power input protection, overcurrent protection, and overheat protection, to prevent damage to the instrument in complex testing environments or due to improper operation.

[0021] The other peripheral circuits mentioned above include USB communication circuits and Bluetooth communication circuits, which enable online upgrades of the instrument firmware. The instrument can be wirelessly operated and its data can be read or shared via a mobile APP connected via Bluetooth.

[0022] Based on the circuit structure of the grounding lead continuity resistance tester described above, another embodiment of this utility model is as follows: Figure 1 The grounding lead continuity resistance tester shown includes a main control module, which is connected to both a voltage measurement module and a current measurement module. The voltage measurement module has a voltage sampling circuit connected to the acquisition terminal. The current measurement module also has a current sampling circuit connected to the acquisition terminal. The main control module further includes a PWM control circuit, which is connected to a constant current circuit. The constant current circuit is connected to a constant current output circuit, which is connected to a protection circuit connected to the acquisition terminal. The protection circuit is used to obtain output feedback from the constant current output circuit and adjust the output current. The protection circuit is also connected to a freewheeling discharge circuit, which is also connected to the acquisition terminal. The aforementioned protection circuit is grounded. As shown in the figure, the current sampling circuit also includes a first signal amplification circuit connected to the main control module. The first signal amplification circuit is also connected to a first filter circuit, which is connected to the voltage sampling circuit. The voltage sampling circuit also includes a second signal amplification circuit connected to the main control module. The second signal amplification circuit is also connected to a second filter circuit, which is connected to a differential circuit, which is connected to the current sampling circuit.

[0023] Meanwhile, the aforementioned main control module is also connected to a wireless communication module, a Bluetooth module, a USB communication module, and an LCD screen.

[0024] Based on the above embodiments, the grounding lead continuity resistance tester of this utility model uses a high-speed microcontroller as its core, incorporates a built-in rechargeable lithium battery, and employs a high-speed A / D converter and programmable current source technology. It features resistance-temperature conversion and multiple protection functions, including back EMF protection, open-circuit protection, power failure protection, and overheat alarm. It achieves high-precision, high-stability measurement results and highly automated measurement functions, characterized by large output current, high accuracy, wide measurement range, stable data, good repeatability, strong anti-interference ability, comprehensive protection functions, and fast charging and discharging speed. It also features automatic self-testing, data processing, display, automatic discharge, and discharge indication functions. It is characterized by rapid measurement, high measurement accuracy, simple operation, small size, light weight, and portability. The 5.6-inch color LCD display and simple button operation interface make the instrument easy to use and clear. At the same time, the self-testing function reduces the difficulty of instrument use and maintenance.

[0025] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this utility model.

[0026] Although the present invention has been described herein with reference to several illustrative embodiments, it should be understood that many other modifications and implementations can be devised by those skilled in the art, which will fall within the scope and spirit of the principles disclosed herein. More specifically, various variations and modifications can be made to the components and / or layout of the subject matter combination within the scope of the disclosure, drawings, and claims. Besides variations and modifications to the components and / or layout, other uses will be apparent to those skilled in the art.

Claims

1. A grounding lead continuity resistance tester, comprising a main control module, characterized in that: The main control module is connected to the voltage measurement module and the current measurement module respectively. The voltage measurement module has a voltage sampling circuit, which is used to connect to the acquisition terminal. The current measurement module has a current sampling circuit, which is used to connect to the acquisition terminal. The main control module is also connected to a PWM control circuit, which is connected to a constant current circuit. The constant current circuit is connected to a constant current output circuit, which is connected to a protection circuit. The protection circuit is used to connect to the acquisition terminal. The constant current circuit is used to obtain output feedback from the constant current output circuit and adjust the output current; The protection circuit is also connected to a freewheeling discharge circuit, which is also used to connect to the acquisition terminal. The protection circuit is grounded.

2. The grounding lead continuity resistance tester according to claim 1, characterized in that: The current sampling circuit further includes a first signal amplification circuit, which is connected to the main control module. The first signal amplification circuit is also connected to a first filter circuit, which is connected to the voltage sampling circuit.

3. The grounding lead continuity resistance tester according to claim 1 or 2, characterized in that: The voltage sampling circuit further includes a second signal amplification circuit, which is connected to the main control module. The second signal amplification circuit is also connected to a second filter circuit, which is also connected to a differential circuit. The differential circuit is connected to the current sampling circuit.

4. The grounding lead continuity resistance tester according to claim 1, characterized in that: The main control module is also connected to a wireless communication module, a Bluetooth module, a USB communication module, and an LCD screen.

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