5results about How to "Line selection is accurate" patented technology

The invention relates to a power distribution network fault detection method based on generalized S transformation containing variable factors, and belongs to the technical field of power distribution network fault detection. Data such as a time-frequency spectrum and transient energy are obtained through generalized S transformation containing variable factors, and three line selection criteria of a time-frequency spectrum comprehensive similarity coefficient, a transient energy peak value and a transient energy relative entropy are constructed; and multi-criterion fusion is realized in combination with a D-S evidence theory, so that a line selection result of a single criterion is subjected to comprehensive analysis of multi-criterion fusion, and a more accurate line selection result is obtained. According to the method, accurate line selection can be carried out in different fault distances, fault lines, fault initial angles, fault grounding resistances and noise environments, and the method has good adaptability, sensitivity and anti-interference performance. According to the method, the calculated transient energy characteristics are converted into a reliability distribution function to construct an evidence combination, and different fault characteristic quantities are utilized to measure the credibility to construct a line selection criterion, so that mutual complementation and mutual fusion are realized, and a more accurate line selection result is obtained.

A distribution network intelligent switch device, the device includes an electronic transformer measurement unit, a protection control unit, a circuit breaker, and an intelligent terminal; the electronic transformer measurement unit is connected to the protection control unit, the protection control unit is connected to the circuit breaker, and the protection control unit is wirelessly connected to the intelligent terminal. The device also includes an online energy acquisition unit, the online energy acquisition unit is respectively connected to the electronic transformer measurement unit and the protection control unit, and the online energy acquisition unit is used to obtain energy from the distribution line. The invention provides a distribution network intelligent switch device, which can effectively reduce the size and weight of the equipment, improve the intelligence level of the switch, simplify the operation process, and realize real-time and accurate monitoring of the distribution network status and fault judgment.

This invention relates to a distribution network fault detection method based on the generalized S-transform with variable factors, belonging to the field of distribution network fault detection technology. This invention obtains data such as time-frequency spectrum and transient energy through the generalized S-transform with variable factors, and constructs three line selection criteria: a comprehensive similarity coefficient of time-frequency spectrum, peak transient energy, and relative entropy of transient energy. Combining this with D-S evidence theory, it achieves multi-criteria fusion, enabling comprehensive analysis of line selection results based on multiple criteria, resulting in more accurate line selection. This invention can accurately select lines under different fault distances, fault lines, fault initial angles, fault grounding resistances, and noise environments, exhibiting good adaptability, sensitivity, and anti-interference capabilities. This invention converts the calculated transient energy characteristics into a confidence allocation function to construct evidence combinations, using different fault feature quantities to measure the confidence level and construct line selection criteria, thereby complementing and fusing them to obtain more accurate line selection results.

The invention discloses a distribution network fault positioning method and system. The method comprises the following steps: installing a traveling wave acquisition device at each end point of a distribution network; obtaining a shortest traveling wave transmission path and a corresponding path distance array and a boundary position array according to the network topology of the distribution network; fault traveling wave current waveforms sent by all traveling wave acquisition devices are obtained, and effective waveforms and effective paths are obtained; wavelet decomposition is carried out on the effective waveform, and double-end distance measurement is carried out on all effective paths in sequence; judging an initial fault section and an initial distance measurement result according to the double-end distance measurement result and the path distance array in sequence; and comprehensively judging a final fault section and a final distance measurement result according to the initial fault section and the initial distance measurement result. By adopting the scheme of the invention, only the traveling wave acquisition devices need to be installed at all endpoints of the distribution network, the intermediate nodes do not need to be installed, the number of the devices is reduced, the fault points are on multiple paths, a correct distance measurement result can be obtained even if the traveling wave acquisition of a certain device fails, and the fault tolerance is high.

The present invention provides a method and device for determining a fault line of a high-resistance grounding fault in a distribution network, the method comprising: injecting a compensation current into the distribution network through a controllable voltage source; reducing the output voltage amplitude of the controllable voltage source, thereby reducing the compensation current and obtaining the zero-sequence current value of each distribution line after the reduction; determining the fault line according to the zero-sequence current value of each distribution line after the reduction. The present invention adjusts the fault capacitive current compensation amount, injects the compensation current, and then gradually reduces the compensation current, thereby utilizing the current characteristics of the fault line to achieve accurate line selection of the high-resistance grounding fault line. By adopting the fault line selection method of the present invention, the action / alarm threshold of the line selection device can be appropriately increased to avoid erroneous action / alarm of the device, improve the fault characteristic amount during high-resistance grounding, achieve accurate selection of the fault line, and thus quickly remove the fault.