Resonance point detecting method based on similarity of voltage and current harmonics
A technology of voltage, current and detection method, applied in frequency measurement device, frequency to amplitude conversion, etc., can solve the problems of hysteresis, slow speed, and inability to real-time online detection in the detection process, and achieve simple implementation, small amount of calculation, and real-time real-time detection. The effect of online detection
Active Publication Date: 2019-07-12
QINGDAO TOPSCOMM COMM
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Problems solved by technology
[0003] At present, companies and universities have made a lot of achievements in the detection of resonance points, and have produced special detection equipment, but such equipment is expensive, the detection process is complicated and slow
When the device detects the required signal, it needs to be uploaded to the master station for analysis. The detection process has a lag and cannot be detected online in real time.
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[0038] Attached below Figure 1-13 The present invention is further described with examples, to specifically set forth the technical solutions of the present invention. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.
[0039] combined with figure 1 , a kind of resonance point detection method based on voltage and current harmonic similarity of the present invention, comprises the following steps,
[0040] Step 1: Use a low-frequency carrier transmitter to inject carrier current signals with amplitudes of 7A and frequencies of 11, 22, 25, and 59 times into the low-voltage side of the transformer.
[0041] Step 2: Detect the voltage signal U(t) and current signal I(t) on the low-voltage side of the transformer. The waveforms are as follows: Figure 2 to Figure 5 shown.
[0042] Step 3, according to the sliding DFT algorithm, respectively extract th...
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The invention discloses a resonance point detecting method based on similarity of voltage and current harmonics. The method comprises the following steps of step 1, injecting carrier voltage signals of equal amplitude and different frequencies to the low voltage side of a transformer by using a low frequency carrier transmitter; step 2, detecting a voltage signal U(t) and a current signal I(t) onthe low voltage side of the transformer; step 3, extracting the voltage and current harmonics in the measurement signal according to the sliding DFT algorithm; step 4, calculating the similarity between waveforms of the voltage and current harmonics according to the cosine similarity calculation formula; and step 5, determining the resonance point based on the similarity between the calculated voltage and current harmonics. The method provided by the invention is simple to implement, and only needs to measure the voltage and current signals on the low voltage side of the transformer. In addition, the method has a small amount of calculation, and the measurement data does not need to be uploaded to the main station and can be analyzed locally, so that real-time online detection of the resonance point can be realized.
Description
technical field [0001] The invention relates to the field of distribution network automation systems, and relates to a resonance point detection method based on voltage and current harmonic similarity. Background technique [0002] The power factor is a very important performance index in the power system. In order to improve the power factor of the system, the common practice is to switch reactive power compensation capacitor banks in the system, and generally put in capacitors of different capacities according to different loads of the system. Group, increase the voltage of the transmission line of the power system, reduce line loss, and improve economic benefits. However, due to the widespread existence of harmonic sources in the power grid system, when the compensation capacitor is switched to the system, it is likely to cause parallel resonance between the system and the compensation capacitor, causing the compensation capacitor to generate a large resonance current, th...
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IPC IPC(8): G01R23/06
CPCG01R23/06
Inventor 范建华狄克松曹乾磊尹怀强张亚南徐鹏飞李健勋赵新举刘玉林
Owner QINGDAO TOPSCOMM COMM