CN107329052B - Discharge electromagnetic wave time delay value estimation method based on analog signal - Google Patents
Discharge electromagnetic wave time delay value estimation method based on analog signal Download PDFInfo
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- CN107329052B CN107329052B CN201710375481.8A CN201710375481A CN107329052B CN 107329052 B CN107329052 B CN 107329052B CN 201710375481 A CN201710375481 A CN 201710375481A CN 107329052 B CN107329052 B CN 107329052B
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- 238000000034 method Methods 0.000 title claims abstract description 12
- 238000001514 detection method Methods 0.000 claims abstract description 12
- 238000007599 discharging Methods 0.000 claims description 3
- 238000003745 diagnosis Methods 0.000 abstract description 4
- 238000006243 chemical reaction Methods 0.000 description 5
- 239000011810 insulating material Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
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Abstract
The invention belongs to the technical field of power equipment fault diagnosis, and particularly relates to a discharge electromagnetic wave time delay value estimation method based on an analog signal. The invention uses two sensors to receive the electromagnetic wave signal generated by discharge and records it as the default analog signal; the received analog signal is converted into two sine wave signals through a band-pass filter with the bandwidth of 400-600 MHz; passing the two sine wave signals through a local oscillator (300 MHz); then the signal passing through the local oscillator passes through a low-pass filter with the middle frequency of 100 MHz; the resulting signal is compared with signal v21(t) performing quadrature detection and passing through a low-pass filter again; the phase difference between the signals, namely the time delay value of the original signal, is calculated by using the formula. The invention can avoid using digital signal recording devices such as oscilloscopes and the like, and greatly reduces the size, the weight and the economic cost of the algorithm matching device.
Description
Technical Field
The invention belongs to the technical field of power equipment fault diagnosis, and particularly relates to a discharge electromagnetic wave time delay value estimation method based on an analog signal.
Background
In an electric power system, partial discharge or spark discharge is a precursor to deterioration or failure of an insulating material, and high-frequency radiation electromagnetic waves generated by the discharge also cause electromagnetic interference with power transmission and distribution lines, communication equipment near a substation, television broadcast signals, and the like. Therefore, in order to find the aged part of the insulating material early, avoid insulation failure and avoid interference with the surrounding electromagnetic environment, the position of the discharge source needs to be accurately positioned. In a conventional algorithm based on the diagnosis of discharging electromagnetic waves, an antenna is usually used to receive electromagnetic wave signals, then the waveform of the electromagnetic waves is recorded by an a/D conversion device, and then a delay value is estimated by a specific algorithm. Although this method can effectively record waveforms, a/D conversion and oscilloscope recording of waveforms often take some time and cannot meet the requirement of rapid analysis and diagnosis.
Disclosure of Invention
The invention aims to provide a discharge electromagnetic wave time delay value estimation method based on an analog signal, which aims to obtain an accurate time delay value between signals from a recorded analog waveform without using an A/D (analog/digital) conversion device.
In order to realize the purpose of the invention, the invention is realized by the following technical scheme:
a discharge electromagnetic wave time delay value estimation method based on analog signals comprises the following operation steps:
(1) receiving electromagnetic wave signals generated by discharge by two sensors and recording the electromagnetic wave signals as default analog signals;
(2) the received analog signal is converted into two sine wave signals through a band-pass filter with the bandwidth of 400-600 MHz;
(3) passing the two sine wave signals in the step 2 through a local oscillator (300 MHz);
(4) then the signal passing through the local oscillator in the step 3 passes through a low-pass filter with the middle frequency of 100 MHz;
(5) combining the signal obtained in step 4 with a signal v21(t) performing quadrature detection and passing through a low-pass filter again;
(6) the phase difference between the signals, namely the time delay value of the original signal, is calculated by using the formula.
The distance between the two sensors is 10 cm-30 cm.
The electromagnetic wave signal received by the sensor is converted into two sine wave signal waveforms s through a band-pass filter with the bandwidth of 400-600MHz1(t) and s2(t) so that a phase difference proportional to the value of the time delay between the originally received electromagnetic wave signals is still maintained.
The two sine wave signal waveforms are respectively connected with two signals v output by a local oscillator (300MHz) with pi/2 phase difference1(t) and v2(t) multiplying by the output of vs of 100MHz intermediate frequency through a low pass filter12(t)、vs11(t) and vs21(t) a signal; wherein: v. of1(t) signals 1, v representing the local oscillator output2(t) represents a signal 2 outputted from the local oscillator, and has a phase difference of pi/2 from the signal 1, vs12(t) represents v1(t) and s2(t) the signal multiplied and then output through a low-pass filter, vs11(t) represents v1(t) and s1(t) the signal multiplied and then output through a low-pass filter, vs21(t) represents v2(t) and s1(t) the multiplied signals are passed through a low pass filter, t being time; said signal vs11(t) and vs12(t) as reference, for the signal v21(t) the signal obtained by quadrature detection and passing through the low-pass filter again can be represented as us12-21(t) and us11-21(t)；
The two sine wave signals s1(t) and s2The phase difference θ between (t) can be derived from the following equation:
in the above formula: theta denotes the signal s1(t) and s2(t) a phase difference therebetween; us12-21(t) represents the signal vs12(t) and v21(t) a signal which is subjected to quadrature detection and output through a low-pass filter; us11-21(t) represents the signal vs11(t) and v21(t) a signal which is subjected to quadrature detection and output through a low-pass filter; t represents time;
the obtained phase difference is obtained by 1 group of data at a certain time after the antenna receives the trigger action.
The invention has the advantages and beneficial effects that:
the invention can omit an A/D conversion device and directly analyze the waveform of the analog signal to obtain the required time delay value, avoids using a digital signal recording device such as an oscilloscope and the like, and greatly reduces the size, the weight and the economic cost of an algorithm matching device.
Detailed Description
The invention relates to a discharge electromagnetic wave time delay value estimation method based on an analog signal, which is realized by two sensors, a band-pass filter, a local oscillator and a low-pass filter.
The distance between the two sensors is 10 cm-30 cm;
the electromagnetic wave signal received by the sensor is converted into two sine wave signal waveforms s through a band-pass filter with the bandwidth of 400-600MHz1(t) and s2(t) so that a phase difference proportional to the time delay value between the originally received electromagnetic wave signals is still maintained;
the two sine wave signal waveforms are respectively connected with two signals v output by a local oscillator (300MHz) with pi/2 phase difference1(t) and v2(t) multiplying by the output of vs of 100MHz intermediate frequency through a low pass filter12(t)、vs11(t) and vs21(t) a signal; wherein: v. of1(t) signals 1, v representing the local oscillator output2(t) local vibrationThe signal 2 output by the oscillator has a phase difference of pi/2 with the signal 1, vs12(t) represents v1(t) and s2(t) the signal multiplied and then output through a low-pass filter, vs11(t) represents v1(t) and s1(t) the signal multiplied and then output through a low-pass filter, vs21(t) represents v2(t) and s1(t) the multiplied signal is passed through a low pass filter and is output, t being time.
Said signal vs11(t) and vs12(t) as reference, for the signal v21(t) the signal obtained by quadrature detection and passing through the low-pass filter again can be represented as us12-21(t) and us11-21(t)；
The two sine wave signals s1(t) and s2The phase difference θ between (t) can be derived from the following equation:
in the above formula: theta denotes the signal s1(t) and s2(t) a phase difference therebetween; us12-21(t) represents the signal vs12(t) and v21(t) a signal which is subjected to quadrature detection and output through a low-pass filter; us11-21(t) represents the signal vs11(t) and v21(t) a signal which is subjected to quadrature detection and output through a low-pass filter; t represents time.
The phase difference can be obtained by only 1 group of data at a certain moment after the antenna receives the trigger action, and a traditional A/D conversion device is not used for recording the original waveform of the electromagnetic wave.
When the method is implemented specifically, the operation steps are as follows:
(1) receiving electromagnetic wave signals generated by discharge by two sensors and recording the electromagnetic wave signals as default analog signals;
(2) the received analog signal is converted into two sine wave signals through a band-pass filter with the bandwidth of 400-600 MHz;
(3) passing the two sine wave signals in the step 2 through a local oscillator (300 MHz);
(4) then the signal passing through the local oscillator in the step 3 passes through a low-pass filter with the middle frequency of 100 MHz;
(5) combining the signal obtained in step 4 with a signal v21(t) performing quadrature detection and passing through a low-pass filter again;
(6) the phase difference between the signals, namely the time delay value of the original signal, is calculated by using the formula.
Claims (3)
1. A discharge electromagnetic wave time delay value estimation method based on analog signals is characterized by comprising the following steps: the operation steps are as follows:
(1) receiving electromagnetic wave signals generated by discharge by two sensors and recording the electromagnetic wave signals as default analog signals;
(2) the received analog signal is converted into two sine wave signals through a band-pass filter with the bandwidth of 400-600 MHz;
(3) passing the two sine wave signals in the step (2) through a local oscillator;
(4) then, the signal passing through the local oscillator in the step (3) passes through a low-pass filter with the intermediate frequency of 100MHz to obtain a signal vs11(t)、vs12(t) and vs21(t)；
(5) The signal vs obtained in the step (4) is processed11(t)、vs12(t) is respectively related to the signal vs21(t) quadrature detection is performed and the signal us is obtained by passing the quadrature detection through a low-pass filter again12-21(t) and us11-21(t)；
(6) And (4) calculating the phase difference between the signals obtained in the step (5) through the following formula, namely the time delay value of the original signal: two sine wave signals s1(t) and s2The phase difference θ between (t) can be derived from the following equation:
in the above formula: theta denotes the signal s1(t) and s2(t) a phase difference therebetween; us12-21(t) represents the signal vs12(t) and vs21(t) carrying outDetecting the signal through an alternating wave and outputting the signal through a low-pass filter; us11-21(t) represents the signal vs11(t) and vs21(t) a signal which is subjected to quadrature detection and output through a low-pass filter; t represents time;
the obtained phase difference is obtained by 1 group of data at a certain moment after the antenna receives the trigger action;
the two sine wave signal waveforms are respectively connected with two signals v output by a local oscillator with pi/2 phase difference1(t) and v2(t) multiplying by the output of vs of 100MHz intermediate frequency through a low pass filter12(t)、vs11(t) and vs21(t) a signal; wherein: v. of1(t) signals 1, v representing the local oscillator output2(t) represents a signal 2 outputted from the local oscillator, and has a phase difference of pi/2 from the signal 1, vs12(t) represents v1(t) and s2(t) the signal multiplied and then output through a low-pass filter, vs11(t) represents v1(t) and s1(t) the signal multiplied and then output through a low-pass filter, vs21(t) represents v2(t) and s1(t) the multiplied signal is passed through a low pass filter and is output, t being time.
2. The method for estimating the time delay value of the discharging electromagnetic wave based on the analog signal as claimed in claim 1, wherein: the distance between the two sensors is 10 cm-30 cm.
3. The method for estimating the time delay value of the discharging electromagnetic wave based on the analog signal as claimed in claim 1, wherein: the electromagnetic wave signal received by the sensor is converted into two sine wave signal waveforms s through a band-pass filter with the bandwidth of 400-600MHz1(t) and s2(t) so that a phase difference proportional to the value of the time delay between the originally received electromagnetic wave signals is still maintained.
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| CN1501590A (en) * | 1994-11-30 | 2004-06-02 | ���µ�����ҵ��ʽ���� | Receiving circuit |
| JP3789275B2 (en) * | 2000-02-28 | 2006-06-21 | 三菱電機株式会社 | Subcarrier frequency signal demodulator |
| JP4492264B2 (en) * | 2004-09-13 | 2010-06-30 | 株式会社日立製作所 | Quadrature detector and quadrature demodulator and sampling quadrature demodulator using the same |
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| CN202583398U (en) * | 2012-02-16 | 2012-12-05 | 安徽理工大学 | Mixing technology based partial discharge signal collection apparatus |
| CN102866334A (en) * | 2012-10-19 | 2013-01-09 | 上海市电力公司 | Vehicle-mounted local discharge locating system for mobile substation and locating method thereof |
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