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CN-121978584-A - Early diagnosis method and early diagnosis system for arc short-circuit fault of reactor based on open triangular voltage waveform collapse characteristics

CN121978584ACN 121978584 ACN121978584 ACN 121978584ACN-121978584-A

Abstract

The invention relates to a method and a system for early diagnosis of arc short-circuit faults of a reactor based on collapse characteristics of open triangular voltage waveforms, wherein the method comprises the steps of acquiring secondary sides of voltage transformers at two ends of a three-phase series reactor in a high-voltage parallel capacitor bank in real time and sequentially connecting the secondary sides to obtain open triangular voltage signals; sampling according to a preset sampling frequency, calculating the open triangular voltage change rate of adjacent sampling time, judging that a waveform abnormality occurs when the absolute value of the voltage change rate at the current time is larger than a preset threshold value and is different from the voltage change rate at the last time, counting the accumulated times of the waveform abnormality in a window in a preset time, and judging that an arc short circuit fault occurs in the series reactor and triggering an alarm if the accumulated times are larger than a preset time limit value. According to the invention, through analyzing the collapse mutation characteristics of the open triangular voltage waveform, accurate identification can be performed in a slight short circuit stage in the very early stage of the fault, and the sensitivity and reliability of diagnosis are remarkably improved.

Inventors

  • ZHAO QICHENG
  • MA WENHAO
  • XIE CHENG
  • CHEN CHAO
  • LI PENG

Assignees

  • 国网浙江省电力有限公司电力科学研究院

Dates

Publication Date
20260505
Application Date
20260407

Claims (10)

  1. 1. An early diagnosis method for arc short-circuit faults of a reactor based on open triangular voltage waveform collapse characteristics is applied to a high-voltage parallel capacitor bank and is characterized by comprising the following steps: acquiring an opening triangular voltage signal of a three-phase series reactor in the high-voltage parallel capacitor bank in real time; sampling the open triangular voltage signal according to a preset sampling frequency, and calculating the voltage change rate of the open triangular voltage signal at adjacent sampling moments; judging whether the absolute value of the voltage change rate at the current moment is larger than a preset change rate threshold value, if yes, judging that the opening triangular voltage signal at the current moment has a waveform abnormality once, wherein the voltage change rate at the current moment is different from the voltage change rate at the last sampling moment; starting a preset timing window, and counting the accumulated times of waveform abnormality in the timing window; And if the accumulated times are larger than a preset times limit value, judging that arc short circuit faults occur in the three-phase series reactor, and triggering an alarm.
  2. 2. The early diagnosis method for arc short circuit fault of reactor based on open delta voltage waveform collapse characteristic according to claim 1, wherein the calculating the voltage change rate of the open delta voltage signal at adjacent sampling time comprises: calculating the difference value between the first voltage amplitude acquired at the current moment and the second voltage amplitude acquired at the last sampling moment to obtain a voltage variation; Dividing the voltage change by a sampling period corresponding to the preset sampling frequency to obtain the voltage change rate.
  3. 3. The method for early diagnosis of arc short circuit fault in reactor based on open delta voltage waveform collapse feature according to claim 1, wherein after said starting a preset timing window and counting the cumulative number of waveform anomalies within said timing window, said method further comprises: and if the accumulated times are smaller than or equal to the preset times limit value at the ending time of the timing window, resetting the accumulated times, and waiting for waveform abnormality of the open triangular voltage signal again.
  4. 4. The method for early diagnosis of a reactor arc short circuit fault based on open delta voltage waveform collapse characteristics of claim 1, further comprising, after said calculating the voltage change rate of said open delta voltage signal at adjacent sampling instants: calculating the difference value between the voltage change rate at the current moment and the voltage change rate at the last sampling moment to obtain a slope change quantity; And quantifying the collapse characteristic of the open triangular voltage waveform based on three parameters of the open voltage variation, the voltage variation rate and the slope variation between adjacent sampling moments.
  5. 5. The method for early diagnosis of arc short-circuit faults of a reactor based on collapse characteristics of open delta voltage waveforms according to claim 1, wherein the step of acquiring open delta voltage signals of three-phase series reactors in a high-voltage parallel capacitor bank in real time comprises the steps of: collecting terminal voltages of each phase of the three-phase series reactor; And obtaining the open triangular voltage signal by carrying out physical wiring connection or vector summation calculation on the terminal voltage of each phase.
  6. 6. The early diagnosis method for arc short circuit fault of reactor based on open delta voltage waveform collapse characteristic according to claim 1, wherein the time length of the preset timing window and the preset frequency limit are determined according to the specification and voltage class of the high voltage parallel capacitor bank.
  7. 7. The early diagnosis method for arc short-circuit fault of reactor based on open triangular voltage waveform collapse characteristic according to claim 1, wherein the preset sampling frequency is not less than 16kHz.
  8. 8. The early diagnosis method for arc short circuit fault of reactor based on open delta voltage waveform collapse characteristic according to claim 1, wherein the preset change rate threshold is 25, the time length of the timing window is 2 minutes, and the frequency limit is 2000.
  9. 9. An early diagnosis system for arc short-circuit faults of a reactor based on open triangular voltage waveform collapse characteristics, which is applied to a high-voltage parallel capacitor bank, is characterized by comprising: The voltage acquisition module is used for acquiring an opening triangular voltage signal of the three-phase series reactor in the high-voltage parallel capacitor bank in real time; The data acquisition module is connected with the voltage acquisition module and is used for sampling the opening triangular voltage signal according to a preset sampling frequency; The processor is connected with the data acquisition module and is used for calculating the voltage change rate of the opening triangular voltage signal at the adjacent sampling time, judging whether the absolute value of the voltage change rate at the current time is larger than a preset change rate threshold value, if yes, judging that the opening triangular voltage signal at the current time has waveform abnormality once, starting a preset timing window, and counting the accumulated times of the waveform abnormality in the timing window; And the alarm device is connected with the processor, and when the accumulated times are larger than a preset times limit value, the processor judges that arc short circuit faults occur in the three-phase series reactor and controls the alarm device to trigger an alarm.
  10. 10. The early diagnosis system for arc short-circuit faults of a reactor based on the collapse characteristic of an open delta voltage waveform according to claim 9, wherein the voltage acquisition module comprises voltage transformers connected in parallel to two ends of each phase of the three-phase series reactor, wherein secondary side windings of each phase of the voltage transformers are connected according to an open delta voltage connection method and are used for outputting the open delta voltage signals.

Description

Early diagnosis method and early diagnosis system for arc short-circuit fault of reactor based on open triangular voltage waveform collapse characteristics Technical Field The invention belongs to the technical field of power detection, and particularly relates to an early diagnosis method and system for arc short-circuit faults of a reactor based on collapse characteristics of an opening triangular voltage waveform. Background The high-voltage parallel capacitor bank is an important reactive compensation device in a power grid, and a dry air-core reactor which is usually used in series with the high-voltage parallel capacitor bank is used for inhibiting the closing inrush current and low-frequency harmonic waves of the power grid. In a practical use environment, the inter-turn short-circuit fault state of the series reactor is usually represented by an early inter-turn arc reignition short-circuit fault and an inter-turn fusion short-circuit fault in the middle and later stages. In the prior art, an analytical calculation method based on inductance characteristics, a relay protection and operation maintainer timing infrared inspection method based on current amplitude and a phase voltage and current phase angle deviation change monitoring method are mainly adopted for fault detection of the dry type air core reactor. In an actual grid operating environment, however, complex harmonic voltage disturbances inevitably exist on the grid background side, and initial parameter imbalance often exists in the manufacturing or installation process of the three-phase series reactor. Because the early arc reignition short-circuit fault has extremely short duration and extremely weak electrical characteristics, the traditional detection means based on harmonic component extraction or phasor offset calculation are extremely easy to mask the background harmonic interference and the initial parameter imbalance factors, so that the detection sensitivity is greatly reduced. When an early weak turn-to-turn arc short circuit occurs in the series reactor, the actual running state of the series reactor is difficult to accurately identify by the existing method, the condition of missed judgment or delayed judgment is easy to occur, and effective protection action cannot be performed in time before the fault is enlarged into a serious fusion short circuit. Therefore, a scheme capable of overcoming the influence of background harmonic interference and unbalance of device parameters and accurately identifying and diagnosing the early turn-to-turn arc short circuit fault of the reactor is needed in the prior art. Disclosure of Invention It is an object of the present invention to at least solve one or more of the above-mentioned problems occurring in the prior art, in other words, to provide a method and a system for early diagnosis of arc-short fault in a reactor based on open delta voltage waveform collapse characteristics that meets one or more of the above-mentioned needs. In order to achieve the aim of the invention, the invention adopts the following technical scheme: in a first aspect, the invention provides a method for early diagnosis of arc short circuit faults of a reactor based on collapse characteristics of an open triangular voltage waveform, which is applied to a high-voltage parallel capacitor bank and comprises the following steps: acquiring an opening triangular voltage signal of a three-phase series reactor in a high-voltage parallel capacitor bank in real time; Sampling the open triangular voltage signal according to a preset sampling frequency, and calculating the voltage change rate of the open triangular voltage signal at adjacent sampling moments; Judging whether the absolute value of the voltage change rate at the current moment is larger than a preset change rate threshold value, if yes, judging that the opening triangle voltage signal at the current moment has a waveform abnormality once, wherein the voltage change rate at the current moment is different from the voltage change rate at the last sampling moment; starting a preset timing window, and counting the accumulated times of waveform abnormality in the timing window; If the accumulated times are larger than the preset times limit value, the arc short circuit fault inside the three-phase series reactor is judged, and an alarm is triggered. As a preferred embodiment, calculating the voltage change rate of the open triangular voltage signal at adjacent sampling moments includes: Calculating the difference value between the first voltage amplitude value acquired at the current moment and the second voltage amplitude value acquired at the last sampling moment to obtain a voltage variation; Dividing the voltage variation by a sampling period corresponding to a preset sampling frequency to obtain a voltage variation rate. As a preferred embodiment, after starting a preset timing window and counting the cumulative number of waveform anomalies in the timing wi