阅读说明：本技术 换流站接地极接地电阻测量干扰抑制装置及使用方法 (Converter station grounding electrode grounding resistance measurement interference suppression device and use method thereof ) 是由 陈文涛 张陵 吴天博 赵普志 詹仲强 杨柱石 李山 刘磊 于 2021-07-26 设计创作，主要内容包括：本发明涉及换流站直流接地极接地电阻测量技术领域,是一种换流站接地极接地电阻测量干扰抑制装置及使用方法,其前者包括信号采集放大单元、供电单元、处理单元、信号输出单元和信号反馈单元；供电单元用于给信号采集放大单元和信号输出单元供电；信号采集放大单元采集直流电源电压线上的干扰电压信号,并将干扰电压信号处理后输出无损干扰电压信号。本发明通过输出一个与干扰电压信号幅值相等,相位相反的干扰抑制电压信号,并将该干扰抑制电压信号输出至电压表的输入端,使直流接地的电位极线路上干扰电压信号和干扰抑制电压信号相互抵消而接近于零,达到消除信号干扰的效果,提高了换流站直流接地极接地电阻测试的准确度与可信度。(The invention relates to the technical field of converter station direct current grounding electrode grounding resistance measurement, in particular to a converter station grounding electrode grounding resistance measurement interference suppression device and a using method thereof, wherein the converter station grounding electrode grounding resistance measurement interference suppression device comprises a signal acquisition and amplification unit, a power supply unit, a processing unit, a signal output unit and a signal feedback unit; the power supply unit is used for supplying power to the signal acquisition and amplification unit and the signal output unit; the signal acquisition amplifying unit acquires interference voltage signals on a direct-current power supply voltage line, processes the interference voltage signals and outputs lossless interference voltage signals. The interference suppression voltage signal with the same amplitude and the opposite phase as the interference voltage signal is output and is output to the input end of the voltmeter, so that the interference voltage signal and the interference suppression voltage signal on the direct-current grounded potential polar line are mutually counteracted to be close to zero, the effect of eliminating signal interference is achieved, and the accuracy and the reliability of the grounding resistance test of the direct-current grounding electrode of the converter station are improved.)

1. A converter station grounding electrode grounding resistance measurement interference suppression device is characterized by comprising a signal acquisition and amplification unit, a power supply unit, a processing unit, a signal output unit and a signal feedback unit;

the power supply unit is used for supplying power to the signal acquisition and amplification unit and the signal output unit;

the signal acquisition amplifying unit acquires interference voltage signals on a direct-current power supply voltage line, processes the interference voltage signals and outputs lossless interference voltage signals;

the processing unit receives the lossless interference voltage signal, converts and decomposes the lossless interference voltage signal to obtain the amplitude and the phase of the lossless interference voltage signal, and controls the signal output unit according to the lossless interference voltage signal;

the signal output unit outputs an interference suppression voltage signal which is equal to the lossless interference voltage signal in amplitude and opposite in phase according to the control of the processing unit;

the signal feedback unit receives the interference suppression voltage signal and feeds the interference suppression voltage signal back to the processing unit.

2. The interference suppression device for grounding electrode ground resistance measurement of a converter station according to claim 1, characterized in that the signal acquisition and amplification unit comprises a signal sampling module and a signal amplification module; the signal sampling module collects and outputs interference voltage signals on a direct-current power supply voltage line; the signal amplification module receives the interference voltage signal, performs lossless amplification on the interference voltage signal and outputs a lossless interference voltage signal.

3. The interference suppression device for measuring the grounding resistance of the grounding electrode of the converter station according to claim 1 or 2, characterized in that the signal output unit comprises an interference suppression signal module and an interference suppression signal amplification module; the interference suppression signal module outputs an interference suppression voltage signal which is equal to the lossless interference voltage signal in amplitude and opposite in phase according to the control of the processing unit; the interference suppression signal amplification module outputs the amplified interference suppression voltage signal.

4. A use method of an interference suppression device for measuring grounding resistance of a grounding electrode of a converter station is characterized by comprising the following steps:

connecting a signal acquisition amplifying unit between a direct-current power supply voltage line and a grounding electrode line in parallel, and connecting an output end of a signal output unit in parallel with an input end of a voltmeter;

the signal acquisition amplifying unit acquires interference voltage signals on a direct-current power supply voltage line, processes the interference voltage signals and outputs lossless interference voltage signals;

the processing unit receives the lossless interference voltage signal, converts and decomposes the lossless interference voltage signal to obtain the amplitude and the phase of the lossless interference voltage signal, and controls the signal output unit according to the lossless interference voltage signal, so that the signal output unit outputs an interference suppression voltage signal which is equal to the lossless interference voltage signal in amplitude and opposite in phase to the lossless interference voltage signal to the signal feedback unit;

the signal feedback unit receives the interference suppression voltage signal and feeds the interference suppression voltage signal back to the processing unit, the processing unit judges whether the amplitude and the phase of the fed-back interference suppression voltage signal are equal and opposite to those of the lossless interference voltage signal, and if the amplitude and the phase of the fed-back interference suppression voltage signal are equal and opposite to those of the lossless interference voltage signal, the processing unit controls the signal output unit to output the interference suppression voltage signal to the voltmeter.

Technical Field

The invention relates to the technical field of converter station direct current grounding electrode grounding resistance measurement, in particular to a converter station grounding electrode grounding resistance measurement interference suppression device and a use method thereof.

Background

The converter station grounding electrode is used as an important device for returning current to a neutral point on the direct current side of the circulating current station when the direct current transmission system is normal or in a fault state, so that the state detection of the circulating current station direct current grounding electrode is very necessary, wherein the measurement of the direct current grounding resistance of the converter station is an important item. In the measurement of the direct current grounding resistance of the converter station, a direct current power supply is usually arranged in the converter station, and two polar lines of a grounding electrode are respectively used as a current line and a potential line. The direct current power supply is placed in a converter station, a direct current loop is formed by a grounding electrode, one polar line (right polar line, facing the direction of the converter station and the same below) of a grounding electrode circuit and a converter station grounding grid, a potential measuring line utilizes the other polar line (left polar line) of the grounding electrode, wiring as shown in an attached figure 3 is adopted when the grounding resistance of the grounding electrode is measured, when the direct current grounding resistance of the grounding electrode is measured, an ammeter-voltmeter method is adopted, namely direct current I is injected into the direct current grounding electrode, the potential U of the grounding electrode relative to a zero potential reference point is measured, and the grounding resistance R is equal to U/I.

The measurement of the grounding resistance of the high-voltage direct-current grounding electrode can well reflect the through-current capacity of the grounding electrode, and ensure the normal and stable operation of a direct-current circuit, particularly the stable operation in a single-pole earth operation mode. The difference between the method for measuring the grounding resistance of the high-voltage direct-current grounding electrode and the method for measuring the grounding resistance of the high-voltage direct-current grounding electrode is that direct current needs to be injected into the grounding electrode, and the arrangement distances of a current line and a voltage line are long and are generally more than 10 kM. Therefore, the longer voltage and current cause interference which is easily coupled with other power transmission lines in the line, thereby causing influence on the accuracy of measurement.

For coupled interference, the solution can be realized by: (1) removing an interference source: in practice, the common interference source cannot be removed; (2) blocking the coupling pathway: it is difficult to perform interference shielding processing on a test line of several tens of kilometers; therefore, the existing coupling interference mode cannot eliminate the coupling interference of the line, so that the accuracy and the reliability of the grounding resistance test of the direct current grounding electrode of the converter station are reduced.

Disclosure of Invention

The invention provides a converter station grounding electrode grounding resistance measurement interference suppression device and a use method thereof, overcomes the defects of the prior art, and can effectively solve the problem that the accuracy and the reliability of a converter station direct current grounding electrode grounding resistance test are reduced because the coupling interference of a line cannot be eliminated in the conventional coupling interference elimination mode.

One of the technical schemes of the invention is realized by the following measures: a converter station grounding electrode grounding resistance measurement interference suppression device comprises a signal acquisition and amplification unit, a power supply unit, a processing unit, a signal output unit and a signal feedback unit;

the power supply unit is used for supplying power to the signal acquisition and amplification unit and the signal output unit;

the signal acquisition amplifying unit acquires interference voltage signals on a direct-current power supply voltage line, processes the interference voltage signals and outputs lossless interference voltage signals;

the processing unit receives the lossless interference voltage signal, converts and decomposes the lossless interference voltage signal to obtain the amplitude and the phase of the lossless interference voltage signal, and controls the signal output unit according to the lossless interference voltage signal;

the signal output unit outputs an interference suppression voltage signal which is equal to the lossless interference voltage signal in amplitude and opposite in phase according to the control of the processing unit;

the signal feedback unit receives the interference suppression voltage signal and feeds the interference suppression voltage signal back to the processing unit.

The following is a further optimization or/and improvement of one of the above-mentioned technical solutions of the invention:

the signal acquisition amplifying unit can comprise a signal sampling module and a signal amplifying module; the signal sampling module collects and outputs interference voltage signals on a direct-current power supply voltage line; the signal amplification module receives the interference voltage signal, performs lossless amplification on the interference voltage signal and outputs a lossless interference voltage signal.

The signal output unit can comprise an interference suppression signal module and an interference suppression signal amplification module; the interference suppression signal module outputs an interference suppression voltage signal which is equal to the lossless interference voltage signal in amplitude and opposite in phase according to the control of the processing unit; the interference suppression signal amplification module outputs the amplified interference suppression voltage signal.

The second technical scheme of the invention is realized by the following measures: a use method of an interference suppression device for measuring grounding resistance of a grounding electrode of a converter station comprises the following steps:

connecting a signal acquisition amplifying unit between a direct-current power supply voltage line and a grounding electrode line in parallel, and connecting an output end of a signal output unit in parallel with an input end of a voltmeter;

the signal acquisition amplifying unit acquires interference voltage signals on a direct-current power supply voltage line, processes the interference voltage signals and outputs lossless interference voltage signals;

the processing unit receives the lossless interference voltage signal, converts and decomposes the lossless interference voltage signal to obtain the amplitude and the phase of the lossless interference voltage signal, and controls the signal output unit according to the lossless interference voltage signal, so that the signal output unit outputs an interference suppression voltage signal which is equal to the lossless interference voltage signal in amplitude and opposite in phase to the lossless interference voltage signal to the signal feedback unit;

the signal feedback unit receives the interference suppression voltage signal and feeds the interference suppression voltage signal back to the processing unit, the processing unit judges whether the amplitude and the phase of the fed-back interference suppression voltage signal are equal and opposite to those of the lossless interference voltage signal, and if the amplitude and the phase of the fed-back interference suppression voltage signal are equal and opposite to those of the lossless interference voltage signal, the processing unit controls the signal output unit to output the interference suppression voltage signal to the voltmeter.

According to the invention, an interference suppression voltage signal which is equal to the interference voltage signal in amplitude and opposite in phase is output, and the interference suppression voltage signal is output to the input end of the voltmeter, so that the interference voltage signal and the interference suppression voltage signal on the DC grounded potential polar line are mutually offset and approach to zero, the effect of eliminating signal interference is achieved, and the accuracy and the reliability of the grounding resistance test of the DC grounding electrode of the converter station are improved; the invention has no obvious bandwidth limitation by means of mutual cancellation, is different from the traditional first-order filter or second-order filter, and can greatly improve the bandwidth of the whole device to the interference response when in use.

Drawings

Fig. 1 is a schematic circuit structure diagram according to a first embodiment of the present invention.

FIG. 2 is a schematic flow chart of a method according to a second embodiment of the present invention.

Fig. 3 is a schematic diagram of a circuit structure for measuring the dc ground resistance of the existing converter station.

Detailed Description

The present invention is not limited by the following examples, and specific embodiments may be determined according to the technical solutions and practical situations of the present invention.

The invention is further described with reference to the following examples and figures:

the first embodiment is as follows: as shown in fig. 1, the embodiment of the invention discloses an interference suppression device for measuring grounding resistance of a grounding electrode of a converter station, which comprises a signal acquisition and amplification unit, a power supply unit, a processing unit, a signal output unit and a signal feedback unit, wherein the signal acquisition and amplification unit is used for acquiring a signal;

the power supply unit is used for supplying power to the signal acquisition and amplification unit and the signal output unit;

the signal acquisition amplifying unit acquires interference voltage signals on a direct-current power supply voltage line, processes the interference voltage signals and outputs lossless interference voltage signals;

the processing unit receives the lossless interference voltage signal, converts and decomposes the lossless interference voltage signal to obtain the amplitude and the phase of the lossless interference voltage signal, and controls the signal output unit according to the lossless interference voltage signal;

the signal output unit outputs an interference suppression voltage signal which is equal to the lossless interference voltage signal in amplitude and opposite in phase according to the control of the processing unit;

the signal feedback unit receives the interference suppression voltage signal and feeds the interference suppression voltage signal back to the processing unit.

The processing unit is used for receiving the lossless interference voltage signal output by the signal acquisition and amplification unit, performing Fourier transform and Laplace transform on the lossless interference voltage signal to obtain the amplitude and the phase of the lossless interference voltage signal, and controlling the signal output unit according to the lossless interference voltage signal.

When the device works, the signal acquisition and amplification unit is connected between a direct current power supply voltage line and a grounding electrode line in parallel, the output end of the signal output unit is connected at the input end of a voltmeter in parallel, the signal acquisition unit acquires an interference voltage signal on a potential polar line, and outputs a lossless interference voltage signal to the processing unit after lossless amplification of the acquired interference voltage signal, the processing unit converts and decomposes the lossless interference voltage signal to obtain the amplitude and the phase of the lossless interference voltage signal, controls the signal output unit according to the lossless interference voltage signal to enable the signal output unit to output an interference suppression voltage signal which is equal to the amplitude and opposite to the phase of the lossless interference voltage signal, the signal feedback unit receives the interference suppression voltage signal and feeds the interference suppression voltage signal back to the processing unit, and the processing unit compares the fed-back interference suppression voltage signal with the lossless interference voltage signal, if the fed back interference suppression voltage signal is equal to the lossless interference voltage signal in amplitude and opposite in phase, the processing unit controls the signal output unit to output the interference suppression voltage signal to the voltmeter, and at the moment, a detected direct current signal, an interference voltage signal and an interference suppression voltage signal exist on the voltmeter, wherein the interference voltage signal and the interference suppression voltage signal are equal in amplitude and opposite in phase, so that the interference voltage signal and the interference suppression voltage signal are mutually offset and close to zero, and only the detected direct current signal exists in the voltmeter, and the effect of eliminating signal interference is achieved.

The principle of interference suppression of the present invention is as follows:

weak direct current signals to be detected and other interference signals are respectively recorded as: x is the number of_z(t) and x_g(t), during the signal measurement, the output obtained is denoted as x (t), i.e.:

x(t)＝x_z(t)+x_g(t) (1)

in order to be able to realize a direct current signal x under other interference signals_z(t) accurate measurement, first of all, other interfering signals, i.e. x, need to be eliminated_g(t)，

Assuming that the period of the interference signal is T, the waveform repeats every T, that is:

x_g(t)＝x_g(t+kT) (2)

where k is a positive integer and T is the period of the interfering signal.

The interference suppressed signal y (t) is obtained by calculating:

y(t)＝x(t)-x(t+kT) (3)

bringing formula (1) into formula (3) to obtain,

y(t)＝x_z(t)-x_g(t+kT) (4)

as can be seen from the above expressions (1) and (4), the other interference signal x_gAnd (t) is already counteracted, so that the effect of eliminating signal interference is achieved.

In conclusion, the interference suppression voltage signal with the same amplitude and the opposite phase as the interference voltage signal is output and is output to the input end of the voltmeter, so that the interference voltage signal and the interference suppression voltage signal on the DC grounded potential polar line are mutually counteracted to be close to zero, the effect of eliminating signal interference is achieved, and the accuracy and the reliability of the grounding resistance test of the DC grounded electrode of the converter station are improved; the invention has no obvious bandwidth limitation by means of mutual cancellation, is different from the traditional first-order filter or second-order filter, and can greatly improve the bandwidth of the whole device to the interference response when in use.

The interference suppression device for measuring the grounding resistance of the grounding electrode of the converter station can be further optimized or/and improved according to actual needs:

as shown in fig. 1, the signal acquisition and amplification unit includes a signal sampling module and a signal amplification module; the signal sampling module collects and outputs interference voltage signals on a direct-current power supply voltage line; the signal amplification module receives the interference voltage signal, performs lossless amplification on the interference voltage signal and outputs a lossless interference voltage signal.

The signal sampling module can adopt a high-precision signal sampling module, can realize the lossless sampling of various interference voltage signals within 1-10 MHz, is convenient for accurately extracting the interference voltage signals on the voltage line, but the amplitude of the interference voltage signals output by the signal sampling module is smaller, so that the interference voltage signals are amplified in equal proportion by the signal amplification module and then are provided for the processing unit.

As shown in fig. 1, the signal output unit includes an interference suppression signal module and an interference suppression signal amplification module; the interference suppression signal module outputs an interference suppression voltage signal which is equal to the lossless interference voltage signal in amplitude and opposite in phase according to the control of the processing unit; the interference suppression signal amplification module outputs the amplified interference suppression voltage signal.

The output end of the interference suppression signal amplification module is connected in parallel to the input end of the voltmeter when in use, an interference suppression voltage signal is amplified by the interference suppression signal amplification module and then output to the voltmeter, at the moment, a detected direct current signal, an interference voltage signal and an interference suppression voltage signal exist on the voltmeter, the amplitudes of the interference voltage signal and the interference suppression voltage signal are equal, and the phases of the interference voltage signal and the interference suppression voltage signal are opposite, so that the interference voltage signal and the interference suppression voltage signal are mutually offset and close to zero, only the detected direct current signal exists in the voltmeter, and the effect of eliminating signal interference is achieved.

Example two: as shown in fig. 2, the embodiment of the invention discloses a using method of an interference suppression device for measuring grounding resistance of a grounding electrode of a converter station, which comprises the following steps:

s101, connecting a signal acquisition and amplification unit between a direct-current power supply voltage line and a grounding electrode line in parallel, and connecting an output end of a signal output unit in parallel to an input end of a voltmeter;

s102, a signal acquisition and amplification unit acquires interference voltage signals on a direct-current power supply voltage line, processes the interference voltage signals and outputs lossless interference voltage signals;

s103, the processing unit receives the lossless interference voltage signal, converts and decomposes the lossless interference voltage signal to obtain the amplitude and the phase of the lossless interference voltage signal, and controls the signal output unit according to the lossless interference voltage signal, so that the signal output unit outputs an interference suppression voltage signal which is equal to the lossless interference voltage signal in amplitude and opposite in phase to the lossless interference voltage signal to the signal feedback unit; and S104, the signal feedback unit receives the interference suppression voltage signal and feeds the interference suppression voltage signal back to the processing unit, the processing unit judges whether the amplitude and the phase of the fed-back interference suppression voltage signal are equal and opposite to those of the lossless interference voltage signal, and if the amplitude and the phase of the fed-back interference suppression voltage signal are equal and opposite to those of the lossless interference voltage signal, the processing unit controls the signal output unit to output the interference suppression voltage signal to the voltmeter.

The technical characteristics form an embodiment of the invention, which has strong adaptability and implementation effect, and unnecessary technical characteristics can be increased or decreased according to actual needs to meet the requirements of different situations.