CN102680820A - Automatic testing and diagnosing system for corrosion fault points of grounding grid of substation - Google Patents

Abstract

The invention discloses an automatic testing and diagnosing system for corrosion fault points of a grounding grid of a substation. The automatic testing and diagnosing system comprises a data acquisition terminal and a corrosion fault point diagnosis and analysis upper computer, wherein the data acquisition terminal is connected with the corrosion fault point diagnosis and analysis upper computer through a USB (Universal Serial Bus) interface of the corrosion fault point diagnosis and analysis upper computer. The automatic testing and diagnosing system disclosed by the invention has the advantages of high diagnosis efficiency, simplicity and convenience in operation and accuracy in measurement; and under the conditions that no power is failed and large-area digging is not carried out, corrosion and point breaking conditions of the grounding grid can be detected by only means of the resistance among grounding down leads of the grounding grid.

Description

Automatic Test and Diagnosis System for Corrosion Fault Points of Substation Grounding Grid

technical field

The invention relates to a power system safety diagnosis device, in particular to an intelligent diagnosis device for a corrosion fault point of a substation grounding grid.

Background technique

The grounding grid is an important equipment in power system power plants and substations, and it needs to meet the requirements of working grounding, protection grounding and lightning protection grounding at the same time. The ground grid not only provides a common electrical reference point, but also quickly discharges the fault current when the system fails, prevents the ground potential from rising abnormally, ensures that the step voltage, contact voltage and transfer voltage are within the allowable safety range, and ensures the safety of people and equipment . Therefore, the grounding performance of the grounding grid is directly related to the personal safety of the staff in power plants and substations and the normal operation of the equipment. A qualified grounding grid plays a very important role in the safe operation of the power system.

For many years, most of the tests on the grounding network of power systems use the current-voltage method or the grounding meter method to measure the grounding resistance value. The corrosion degree of the grounding grid is tested by injecting a large current into the grounding system through a high-power transformer. Due to the influence of various interference sources, the above measurement methods often cannot meet the requirements of accurate measurement, and the error is relatively large.

Contents of the invention

The technical problem to be solved by the present invention is to provide an automatic test and diagnosis system for substation ground grid corrosion fault points with high diagnostic efficiency, simple operation and accurate measurement. The corrosion and breakpoint of the grounding grid can be detected by checking the resistance between the wires of the grid grounding lead.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical scheme: an automatic test and diagnosis system for corrosion fault points of substation grounding grids, which is characterized in that: it includes a data acquisition terminal and a corrosion fault point diagnosis and analysis host computer, and the data acquisition terminal passes corrosion The USB interface of the upper computer is connected with it for fault point diagnosis and analysis.

Further, the intelligent acquisition terminal includes a microcontroller, a liquid crystal display, and a data acquisition converter equipped with a pre-interference anti-interference circuit, and the data acquisition converter is respectively connected to the microcontroller and a high-precision reference potentiometer and is controlled by it. Control, the data acquisition converter collects the voltage or current signal of each monitoring point of the grounding network, and outputs the current or voltage signal of each monitoring point to the liquid crystal display through the microcontroller, and the corrosion fault point diagnosis and analysis host computer is connected through USB The communication interface is connected with the microcontroller and provides working power for it.

Further, the data acquisition converter further includes an analog-to-digital converter.

Further, the analog-to-digital converter has an SPI serial interface, and is connected to the input interface of the microcontroller through the SPI serial interface.

Further, the analog-to-digital converter is a sigma-delta 24-bit high-precision analog-to-digital converter.

Further, the microcontroller is integrated with USB2.0 interface, SIE and enhanced 8051 microprocessor, and is connected to the host computer for diagnosis and analysis of corrosion fault points through its USB communication interface.

Further, the liquid crystal display is a liquid display integrated with a liquid display module.

The invention can diagnose the corrosion fault point of the substation grounding grid in a short time and make safety assessment and early warning for the corrosion degree of the whole grounding grid. Compared with the traditional shaking meter method and large-area power outage excavation method to find grounding grid breakpoints and corrosion sections, this system provides a reliable and simple practical diagnostic method, which can be used without power failure and large-scale excavation In the case of digging, the corrosion and breakpoint of the grounding grid can be detected only by the resistance between the grounding grid and the grounding lead. In this way, grounding grid faults can be detected in time, and damage to substation equipment and staff caused by grounding grid faults can be avoided, ensuring safe and reliable operation of the power system. This not only has very important practical significance, but also has economic benefits.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and specific embodiment:

Fig. 1 is a schematic diagram of the structural principle of the system of the present invention;

Figure 2 is a schematic diagram of one embodiment of the system of the present invention.

Detailed ways

Fig. 1 more vividly draws the schematic diagram of the structural principle of the system of the present invention, and the whole system mainly consists of two parts: a data acquisition and measurement device and a PC host computer 8 for diagnosing ground grid corrosion, in which application software is provided. The data acquisition and measurement device preferably includes a DC current source 1 capable of providing 0--60A DC current and an intelligent data acquisition terminal 11 . According to the needs, the DC current source 1 inputs the appropriate excitation signal to the ground grid 9 between each measurement point and the excitation point, and then the data acquisition terminal 9 measures the selected measurement point and transmits the data to the ground grid corrosion diagnosis Host computer 8. The corrosion diagnosis and detection software system in the host computer 8 runs on the on-site computer, generates corresponding circuit calculation equations according to the physical topology of the grounding grid, and then calculates the resistance of each segment of the grounding grid through the calculation model based on the collected grounding grid data. Carry out calculations, and then judge the corrosion of the grounding grid.

The invention adopts a man-machine interface, which mainly includes an engineering creation interface, a data collection interface, and a diagnosis result interface. Among them, in the project creation interface, you only need to input the size information of the ground grid to be tested to establish the project and project, and then you can enter the data collection interface for testing. After the test is over, this set of data can be calculated immediately, and the calculation results can be presented on the display screen in an intuitive manner. The color displayed by each flat iron is different according to the degree of corrosion.

The invention highlights the service characteristics of the automatic test and diagnosis of the substation grounding grid, uses electronic detection means to replace the existing manual detection, fully utilizes the advantages of programming the corrosion diagnosis of the grounding grid, and realizes the business of diagnosing the corrosion of the grounding grid The function is expanded and perfected to the greatest extent.

Shown in Fig. 2 is the schematic diagram of a preferred embodiment of the data collection terminal 11 of the present invention, mainly is made up of following parts: Programmable DC power supply 1, microcontroller 2, power supply module 4, program storage module 5 (preferably a 64KB EEPROM), liquid crystal display 6, and preferably includes a system control panel (not shown in the figure),

The data collection terminal 11 further includes a data collection converter 10 equipped with a pre-interference anti-interference circuit. The data acquisition converter 10 communicates with the microcontroller 2 and the high-precision reference potentiometer 7 and is controlled by them. The data acquisition converter 10 collects the voltage or current signal of each monitoring point of the grounding grid 9, and outputs the current or voltage signal of each monitoring point to the liquid crystal display 6 for display through the microcontroller 2 for calculation and data processing.

The upper computer 8 is connected with the microcontroller 2 through the USB communication interface and provides working power for it.

The pre-interference anti-interference circuit of the present invention includes an integrator and filter built in AD7718, and a front-end filter circuit, which can effectively suppress the interference to the ground network in a strong electromagnetic field environment, especially the interference of power frequency signals. Make the collected data meet the requirements of accuracy, stability and reliability.

Further, the data acquisition converter 10 includes a plurality of high-precision analog-to-digital converters 3 .

Further, the analog-to-digital converter 3 has an SPI serial interface, and is connected to the input interface of the microcontroller 2 through the SPI serial interface.

Further, the analog-to-digital converter 3 is a sigma-delta type 24-bit high-precision analog-to-digital converter.

Further, the microcontroller 2 is integrated with a USB2.0 interface, SIE and an enhanced 8051 microprocessor, and is connected to the host computer 8 for diagnosis and analysis of corrosion fault points through its USB communication interface.

Further, the liquid crystal display 6 is a liquid display integrated with a liquid display module.

The transmission mode of the data acquisition terminal 11 of the present invention is: use the intelligent grounding grid data acquisition terminal to simultaneously collect multiple signals of the grounding grid test node, and after passing through the high-precision analog-to-digital converter 3, transmit the 24bit digital signal to the micro-controller through the SPI interface device 2 (CY7C68013), and then send the data to the host computer 2 through the USB interface of the microcontroller 2 for processing, judgment and analysis. At the same time, it is sent to the liquid crystal display 6 through the IIC interface SLC and SDA of the CY7C68013 microcontroller 2 .

The corrosion failure point diagnosis and analysis host computer 8 of the present invention uses Windows NT/win 7 operating system to perform online or offline calculations, generate charts and grids, and output them.

The system design follows open principles, enabling users to enjoy maximum automation of data collection and systematization of corrosion detection and analysis in the actual use environment. In this system, the openness of the system is manifested in the openness of the data acquisition system, database management system and application analysis system. The data exchange and power supply adopt the industry's communication standard USB protocol.

The above is only a specific embodiment of the present invention, but the technical characteristics of the present invention are not limited thereto, any changes or modifications made by those skilled in the art within the field of the present invention are covered by the patent scope of the present invention among.

Claims (7)

1. grounding net of transformer substation corrodes the automatic test diagnosis system in trouble spot; It is characterized in that: comprise data collection station (11) and corrosion trouble spot diagnostic analysis host computer (8), said data collection station (11) is attached thereto through the usb communication interface that corrodes trouble spot diagnostic analysis host computer (8) and connects.

2. the automatic test diagnosis system in grounding net of transformer substation as claimed in claim 1 corrosion trouble spot; It is characterized in that: said intelligent acquisition terminal (11) comprises microcontroller (2), LCD (6) and is furnished with the data acquisition converter (10) of preposition anti-jamming circuit; Said data acquisition converter (10) is connected with high precision reference potential device (7) with microcontroller (2) respectively and controlled by it; Said data acquisition converter (10) is gathered the voltage or the current signal of each monitoring point of grounded screen (9); And exporting the curtage signal of each monitoring point to LCD (6) through microcontroller (2), said corrosion trouble spot diagnostic analysis host computer (8) is connected with microcontroller (2) through the usb communication interface and working power is provided for it.

3. the automatic test diagnosis system in grounding net of transformer substation as claimed in claim 2 corrosion trouble spot, it is characterized in that: said data acquisition converter (10) further comprises analog to digital converter (3).

4. like the automatic test diagnosis system of claim 2 or 3 described grounding net of transformer substation corrosion trouble spots, it is characterized in that: said analog to digital converter (3) has the SPI serial line interface, and is connected with the input interface of microcontroller (2) through this SPI serial line interface.

5. the automatic test diagnosis system in grounding net of transformer substation as claimed in claim 4 corrosion trouble spot, it is characterized in that: said analog to digital converter (3) is ∑-24 high-precision adcs of △ type.

6. the automatic test diagnosis system in grounding net of transformer substation as claimed in claim 2 corrosion trouble spot; It is characterized in that: said microcontroller (2) is integrated with USB2.0 interface, SIE and enhancement mode 8051 microprocessors, and is connected with corrosion trouble spot diagnostic analysis host computer (8) through its usb communication interface.

7. the automatic test diagnosis system in grounding net of transformer substation as claimed in claim 2 corrosion trouble spot is characterized in that: said LCD (6) the has been integrated liquid article display of liquid article display modules.

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