阅读说明：本技术 特高压管廊回路接触电阻测试系统 (Extra-high voltage pipe gallery circuit contact resistance test system ) 是由 邓福亮 顾红波 潘仁东 孙紫君 于 2021-09-01 设计创作，主要内容包括：本发明公开了一种特高压管廊回路接触电阻测试系统,包括恒流源、采样单元、数据处理控制器、主控制器及人机交互单元。其中采样单元的电流取样传感器为磁通门传感器,恒流源为程控恒流源,恒流源的电流输出上限大于等于300A。根据上述技术方案的特高压管廊回路接触电阻测试系统,磁通门传感器精度高、温飘低,没有温度电势问题,适用于需要较大电流才能测量的GIL管廊回路的接触电阻。同时程控恒流源可以输出足够大的电流,且可以受主控制器控制,满足GIL管廊的主回路接触电阻的测量需求,实现自动化测量。(The invention discloses an extra-high voltage pipe gallery circuit contact resistance testing system which comprises a constant current source, a sampling unit, a data processing controller, a main controller and a man-machine interaction unit. The current sampling sensor of the sampling unit is a fluxgate sensor, the constant current source is a program-controlled constant current source, and the upper limit of the current output of the constant current source is more than or equal to 300A. According to the extra-high voltage pipe gallery return circuit contact resistance test system of above-mentioned technical scheme, fluxgate sensor precision is high, the temperature is wafted low, does not have the temperature potential problem, is applicable to the contact resistance that needs great electric current could be measured GIL pipe gallery return circuit. Meanwhile, the program-controlled constant current source can output enough current and can be controlled by the main controller, the measurement requirement of the contact resistance of the main loop of the GIL pipe gallery is met, and automatic measurement is realized.)

1. The utility model provides an extra-high voltage pipe gallery return circuit contact resistance test system, includes constant current source (100), sampling unit (200), data processing controller (300), main control unit (400) and man-machine interaction unit (500), its characterized in that, the current sampling sensor of sampling unit (200) is the fluxgate sensor, constant current source (100) are programme-controlled constant current source, the current output upper limit more than or equal to 300A of constant current source (100).

2. The extra-high voltage pipe gallery circuit contact resistance test system of claim 1, the sampling unit (200) further comprises a voltage protection circuit, a first gain amplification circuit, a second gain amplification circuit and an analog-to-digital converter, one end of the primary side of the fluxgate sensor is connected with the negative electrode of the constant current source (100), and the other end is electrically connected with the positive electrode of the constant current source (100) through the GIL main loop, the secondary side of the fluxgate sensor is electrically connected with the first gain amplifying circuit through a sampling resistor, the input end of the voltage protection circuit is connected in parallel with the two ends of the GIL loop, the output end of the voltage protection circuit is electrically connected with the second gain amplification circuit, the first gain amplifying circuit and the second gain amplifying circuit are both electrically connected with the data processing controller (300) through the analog-to-digital converter.

3. The ultra-high voltage pipe gallery circuit contact resistance testing system of claim 2, wherein the analog-to-digital converter is a parallel successive approximation analog-to-digital converter.

4. The system of claim 2, wherein the voltage protection circuit is an LC low pass filter circuit.

5. The system of claim 2, wherein the first gain amplifier circuit and the second gain amplifier circuit are both three-stage amplifier circuits.

6. The ultra-high voltage pipe gallery circuit contact resistance testing system of claim 5, wherein each of the first gain amplifying circuit and the second gain amplifying circuit is a program-controlled amplifying circuit including an operational amplifier and a program-controlled voltage divider chip, and the three program-controlled voltage dividers are electrically connected to the main controller (400), respectively.

7. The system of claim 4, wherein two clamping diodes are disposed between the voltage protection circuit and the second gain amplification circuit.

8. The system for testing the contact resistance of the extra-high voltage pipe gallery circuit according to claim 1, wherein the sampling unit (200), the data processing controller (300), the main controller (400) and the human-computer interaction unit (500) are integrated in a 4U metal chassis.

9. The system for testing the contact resistance of the extra-high voltage pipe gallery circuit according to claim 8, wherein the human-computer interaction unit (500) comprises a keyboard, a liquid crystal display and a data storage device, the keyboard, the liquid crystal display and the data storage device are electrically connected with the main controller (400), and the keyboard and the liquid crystal display device are embedded on the front surface of the 4U-shaped metal cabinet.

Technical Field

The invention relates to the field of electrical equipment, in particular to a contact resistance testing system for an extra-high voltage pipe gallery loop.

Background

GIL (gas insulated metal enclosed transmission line) uses a metal conducting rod to transmit power, and the metal conducting rod is enclosed in a grounded metal shell and is insulated by pressure gas. Compared with the conventional cable, the cable has the remarkable advantages of large transmission capacity, low loss, high personal safety level, polar region of an electromagnetic field, no environmental influence, high running reliability, land occupation saving, no electric (thermal) aging and the like, is particularly suitable for a supplementary transmission technology under the condition of a staggered overhead transmission mode or limited cable transmission, and has lower investment cost and maintenance cost than the cable.

The GIL pipe gallery loop is formed by inserting and connecting a plurality of sections of conducting rods, and whether the inserting and connecting is qualified or not is detected, and the contact resistance between the conducting rods needs to be measured. The existing loop resistance tester has small output capacity and narrow measuring range, and the error caused by the thermoelectric potential of the current sensor is large, so that the current tester cannot support the measurement of the contact resistance of the GIL conductive pipe gallery requiring large current.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a system for testing the contact resistance of the loop of the extra-high voltage pipe gallery, which can output enough current and has high measurement precision and can be used for measuring the contact resistance of the loop of the GIL pipe gallery.

The technical scheme is as follows: the invention relates to an extra-high voltage pipe gallery circuit contact resistance testing system which comprises a constant current source, a sampling unit, a data processing controller, a main controller and a man-machine interaction unit, wherein a current sampling sensor of the sampling unit is a fluxgate sensor, the constant current source is a program-controlled constant current source, and the upper limit of the current output of the constant current source is more than or equal to 300A.

Furthermore, the sampling unit further includes a voltage protection circuit, a first gain amplification circuit, a second gain amplification circuit and an analog-to-digital converter, one end of the primary side of the fluxgate sensor is connected to the negative electrode of the constant current source, the other end of the primary side of the fluxgate sensor is electrically connected to the positive electrode of the constant current source through the GIL main loop, the secondary side of the fluxgate sensor is electrically connected to the first gain amplification circuit through a sampling resistor, the input end of the voltage protection circuit is connected in parallel to the two ends of the GIL loop, the output end of the voltage protection circuit is electrically connected to the second gain amplification circuit, and the first gain amplification circuit and the second gain amplification circuit are both electrically connected to the data processing controller through the analog-to-digital converter.

Further, the analog-to-digital converter is a parallel successive approximation analog-to-digital converter.

Further, the voltage protection circuit is an LC low-pass filter circuit.

Further, the first gain amplifying circuit and the second gain amplifying circuit are both three-stage amplifying circuits.

Furthermore, each stage of the first gain amplification circuit and the second gain amplification circuit is a program control amplification circuit comprising an operational amplifier and a program control voltage divider chip, and the three program control voltage dividers are electrically connected with the main controller respectively.

Furthermore, two clamping diodes are arranged between the voltage protection circuit and the second gain amplification circuit.

Furthermore, the sampling unit, the data processing controller, the main controller and the human-computer interaction unit are all integrated in a 4U metal case.

Furthermore, the human-computer interaction unit comprises a keyboard, a liquid crystal display and a data memory, the keyboard, the liquid crystal display and the data memory are electrically connected with the main controller, and the keyboard and the liquid crystal display are embedded on the front surface of the 4U metal case.

Has the advantages that: compared with the prior art, the invention has the following advantages: the fluxgate sensor has high precision, low temperature drift and no temperature potential problem, and is suitable for the contact resistance of the GIL pipe gallery loop which can be measured only by large current. Meanwhile, the program-controlled constant current source can output enough current, the testing requirement of the contact resistance of the main loop of the GIL pipe gallery is met, and the program-controlled constant current source can be controlled by a controller to realize automatic measurement.

Drawings

FIG. 1 is a system block diagram of a test system according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a voltage protection circuit according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a first gain amplifier circuit according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating a test system according to an embodiment of the present invention.

Detailed Description

The technical scheme of the invention is further explained by combining the attached drawings.

Referring to fig. 1, the system for testing the contact resistance of the extra-high voltage pipe gallery circuit according to the embodiment of the invention comprises a constant current source 100, a sampling unit 200, a data processing controller 300, a main controller 400 and a human-computer interaction unit 500. The human-computer interaction unit 500 and the data controller are electrically connected to the main controller 400, the input end of the sampling unit 200 is connected in series to the GIL main loop to be tested and the constant current source 100 to form a loop, and the output end of the sampling unit 200 is electrically connected to the data processing controller 300. The constant current source 100 is a program-controlled constant current source 100 and is electrically connected to the main controller 400, the upper limit of the current output of the constant current source 100 is greater than or equal to 300A, and the current sampling sensor in the sampling unit 200 is a fluxgate sensor.

According to the extra-high voltage pipe gallery gourd contact resistance test system of the technical scheme, the program-controlled constant current source 100 can perform a series of automatic large current output under the control of the main controller 400, and the measurement of the contact resistance of the GIL pipe gallery main loop with the single-phase load reaching 10m omega is realized. Compared with the traditional shunt, the fluxgate sensor has the problems of high precision, low temperature drift and no temperature potential, and can meet the requirement of the measurement precision of the contact resistance of the GIL main loop. In practice, the data processing controller 300 and the main controller 400 may be ARM, DSP or FPGA.

Referring to fig. 1, in some embodiments, the sampling unit 200 further includes a voltage protection circuit, a first gain amplification circuit, a second gain amplification circuit, and an analog-to-digital converter. The primary side of the fluxgate sensor is connected in series with the constant current source 100 and the GIL pipe gallery main circuit to form a circuit, and the secondary side of the fluxgate sensor is electrically connected with the digital-to-analog conversion module through the first gain amplification circuit. The input of input voltage protection circuit connects in parallel at the both ends of GIL piping lane major loop, and input voltage protection circuit's output passes through second gain amplifier circuit and analog-to-digital converter electric connection, and first gain amplifier circuit and second gain amplifier circuit all pass through analog-to-digital converter and data processing controller 300 electric connection. And a sampling resistor is also arranged between the secondary side of the fluxgate sensor and the first gain amplifying circuit.

In order to meet the requirements of measuring range and precision, the first gain amplifying circuit and the second gain amplifying circuit are three-stage amplifying circuits, each stage is a program-controlled amplifying circuit composed of a program-controlled voltage division chip and an operational amplifier, the three program-controlled voltage division chips are electrically connected with the main controller 400 respectively, resistance values can be adjusted under the control of the main controller 400, and the adjustment of amplification coefficients is achieved. The analog-to-digital converter is a parallel successive approximation type analog-to-digital converter.

Referring to fig. 4, in the present embodiment, the constant current source 100 is disposed in a separate cabinet, and the sampling unit 200, the data processing controller 300, the main controller 400 and the human-computer interaction unit 500 are integrated in a 4U metal chassis. The human-computer interaction unit 500 includes a liquid crystal display, a keyboard, and a data storage electrically connected to the main controller 400. The liquid crystal display and the keyboard are embedded on the front surface of the 4U metal case. During the use, take the contact resistance test to the A looks of GIL piping lane as the example, need borrow the conducting rod of B looks and C looks, as the return direction of experimental electric current and experimental voltage respectively, can reduce two long distance test wires. The detection methods for testing the phase B and the phase C are analogized in turn, and are not described in detail herein.

In this embodiment, the current output range of the programmable constant current source 100 is 0A to 500A, and the programmable constant current source communicates with the main controller 400 through RS485, the main controller 400 selects an ARM controller, and the data processing controller 300 selects a DSP controller. Fluxgate sensorThe current ratio of (1) is 500A/100mA, the accurate level is 0.01 level, and the temperature coefficient is 0.1 ppm/K. The sampling resistor R4 is 20 omega in position, the precision is 0.02 grade, and the temperature coefficient is 5 ppm/K.

Referring to fig. 2, in this embodiment, the input voltage protection circuit is an LC low-pass filter circuit, since the ripple of the test system is mainly the pulse width modulation frequency in the constant current source 100, typically, 10kHz to 20kHz lower, and the LC low-pass filter circuit filters the signal above 10kHz, that is, the interference caused by this ripple can be filtered. The output end of the LC low-pass filter circuit is also provided with a voltage division circuit consisting of resistors R1, R2 and R3 and two clamping diodes D1 and D2, wherein the two clamping diodes are respectively connected with +15V and-15V, so that the output can be clamped between +/-15.6V, and the safety of the second gain amplification circuit is protected. The analog-to-digital converter selects a 16-bit high-speed parallel successive approximation type A/D acquisition chip, the A/D acquisition chip is connected with an internal timer of the DSP processor besides a digital quantity output end, the internal timer continuously sends a clock signal to the A/D acquisition chip, the frequency of the clock signal is 2.56kHz, and the A/D acquisition chip is controlled to measure 2560 times per second.

Referring to fig. 3, the first gain amplifying circuit and the second gain amplifying circuit have the same structure, the programmable voltage divider selects a MAX5431 chip, two paths of digital signals of the MAX5431 chip, namely pin 9 and pin 10 are connected with the main controller 400ARM, the amplification factor of a single-stage amplifying circuit is selected from 1, 2, 4 and 8 by four paths of digital signals, the amplification factors of 1, 2, 4, 8, 16, 32, 64, 128, 256 and 512 can be realized by connecting the two paths of digital signals in series, the voltage signal measurement requirement of 1u Ω organization at 300A is met, and the test requirement of the loop contact resistance of the GIL pipe gallery is met. Pins 6 and 8 of the MAX5431 chip are respectively connected with the corresponding homodromous input end and the corresponding inverse input end of the operational amplifier of the same stage, pin 4 of the MAX5431 chip is connected with the output end of the operational amplifier of the same stage, and the output end of the operational amplifier is connected with pin 2 of the MAX5431 chip of the next stage. Pin 2 of the MAX5431 chip N5 of the first stage is connected with an input signal through an operational amplifier N1B, and the output end of the operational amplifier of the third stage is connected with an A/D acquisition chip. In practical use, a proper program-controlled voltage divider can be selected according to test requirements, and a proper number of stages of the gain amplification circuit is designed.

When the circuit works, the DSP converts the measured values acquired by the two groups of 512-point A/D acquisition chips into floating point numbers, and two groups of frequency domain expressions can be obtained by adopting floating point FFT operation, and further the size of a direct current component and the size and the phase of two groups of ripple signals of each time can be obtained, so that the ratio of two groups of direct current voltages to direct current can be calculated, and the contact resistance value of the circuit can be obtained.