Method for diagnosing commutation failure of extra-high-voltage DC power transmission system
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A technology for UHV DC and transmission systems, which is applied in the directions of measuring electricity, measuring electrical variables, measuring current/voltage, etc., and can solve problems such as commutation failure
Active Publication Date: 2015-12-02
KUNMING UNIV OF SCI & TECH
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[0003] The invention provides a commutation failure fault diagnosis method for UHV DC transmission system, which is used to distinguish line short circuit fault and commutation failure in UHV DC transmi...
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Embodiment 1
[0038] Embodiment 1: as Figure 1-9 As shown, a commutation failure fault diagnosis method for UHVDC transmission system, the specific steps of the UHVDC transmission system commutation failure fault diagnosis method are as follows:
[0039] Step1. After the UHV DC transmission system fails, the data acquisition device on the inverter side collects the fault current data within the time window 5ms after the arrival of the first wave of the fault current traveling wave;
[0040] Step2. Perform phase-to-mode transformation on the collected current signal, extract its 1 modulus, and perform m-layer phase space reconstruction to obtain the reconstructed matrix;
[0041] Step3. Singular value decomposition is performed on the reconstructed matrix, and an appropriate noise reduction order m' is selected according to the distribution trend of the singular value, and then the DC current signal is denoised;
[0042] Step4. Send the noise-reduced signal to the morphological filter to e...
Embodiment 2
[0047] Embodiment 2: as Figure 1-9 As shown, a commutation failure fault diagnosis method for UHVDC transmission system, the specific steps of the UHVDC transmission system commutation failure fault diagnosis method are as follows:
[0048] Step1. After the UHV DC transmission system fails, the data acquisition device on the inverter side collects the fault current data within the time window 5ms after the arrival of the first wave of the fault current traveling wave;
[0049] Step2. Perform phase-to-mode transformation on the collected current signal, extract its 1 modulus, and perform m-layer phase space reconstruction to obtain the reconstructed matrix;
[0050] Step3. Singular value decomposition is performed on the reconstructed matrix, and an appropriate noise reduction order m' is selected according to the distribution trend of the singular value, and then the DC current signal is denoised;
[0051] Step4. Send the noise-reduced signal to the morphological filter to e...
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Abstract
The invention relates to a method for diagnosing a commutation failure of an extra-high-voltage (EHV) DC power transmission system and belongs to the technical field of HVDC power transmission system fault diagnosis. The method comprises steps of: performing hierarchical reconstruction on an extracted DC current signal sequence; denoising the DC current signal sequence, filtering the DC current signal sequence with a morphological filter, and extracting the high-frequency components of the DC current signal sequence; performing Hilbert-Huang transformation on the high-frequency components, solving the instantaneous frequency maximum value f and the instantaneous frequency amplitude mean value A of an intrinsic mode function, setting a frequency threshold value f0 and a amplitude average threshold value A0, determining that the system is faulted if the f is more than or equal to f0 or that the system operates normally if not; and if the system is faulted, determining whether the A is more than or equal to A0, and determining that a line is subjected to a short-circuit fault if yes or that the system is subjected to commutation failure if not. The method may accurately determine the running state, the commutation failure, and the line short-circuit fault of the EHV DC power transmission system.
Description
technical field [0001] The present invention relates to a commutation failure fault diagnosis method for UHVDC transmission system, in particular to a UHVDC transmission system commutation method using singular value decomposition (SVD)-morphological filter and Hilbert-Huang (HHT) transformation A phase failure fault diagnosis method belongs to the technical field of fault diagnosis of high-voltage direct current transmission systems. Background technique [0002] At present, the techniques for judging commutation failures in DC transmission systems are mainly the minimum turn-off angle discrimination method and the minimum voltage drop method. However, these methods have certain limitations. When the line passes through a certain value of transition resistance and a short circuit occurs, the minimum turn-off angle will also be lower than the limited minimum value. In this case, the commutation failure detection device will The short-circuit fault is judged as commutation f...
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