A fault phase selection method for half-wavelength AC transmission lines based on information from both sides

Abstract

The invention discloses a two-side information-based half-wavelength alternating-current power transmission line fault phase selection method. The method includes the following steps that: step 1, synchronous sampling is performed on the voltage and current of a local side and the opposite side of a half-wavelength alternating-current power transmission line, and the voltage and current sampling values of the opposite side are transmitted to the local side; step 2, a phase selection component is constructed through using the line voltage and line current at the two sides of the half-wavelength alternating-current power transmission line; and step 3, the output value of the phase selection component is compared with a threshold value, so that a fault phase can be selected out. The two-side information-based half-wavelength alternating-current power transmission line fault phase selection method is just slightly affected by the operating mode of the half-wavelength alternating-current power transmission line and can assist in correctly selecting out a fault phase. The phase selection component is constructed according to the features of the half-wavelength alternating-current power transmission line, so that the phase selection component is completely suitable for the half-wavelength alternating-current power transmission line. The sensitivity of the two-side information-based fault phase selection method at the two ends of the half-wavelength alternating-current power transmission line is completely the same, so that the method can well cooperate with full-line quick-action protection.

Description

technical field [0001] The invention relates to a half-wavelength AC transmission line fault phase selection method based on information from both sides. Background technique [0002] Half-wavelength AC power transmission refers to the ultra-long-distance three-phase AC power transmission whose electrical distance is close to one power frequency half-wave, that is, 3000km (50Hz). With the construction of Energy Internet, half-wavelength AC power transmission, as an efficient long-distance intercontinental power transmission method, has a good application prospect. [0003] The existing domestic high-voltage line protection mainly adopts the method of combining single-ended phase current sudden change phase selection and sequence component phase selection to realize fault phase selection. However, the distance of the half-wavelength AC transmission line is long, the wave velocity of the zero-sequence modulus is smaller than that of the positive and negative sequence moduli, ...

AI Technical Summary

Problems solved by technology

However, the distance of the half-wavelength AC transmission line is long, the wave velocity of the zero-sequence modulus is smaller than the wave velocity of the positive and negative sequence moduli, the non-fault phase current mutation is large, and the phase selection of the phase current mutation is meaningless

Moreover, when a short circuit occurs near the midpoint of the half-wavelength AC transmission line, the current sequence component at the protection installation is very small, and the phase selection sensitivity of the sequence component is insufficient

[0004] The Chinese invention patent with the application number of 2016100669912 discloses a half-wavelength line free-wave energy protection phase selection method based on unilateral current, which selects and jumps the fault phase through the phase selection element and the free-wave energy protection channel and logical exit, but Because the phase selection element only uses one-side current, it is often greatly affected by the operation mode, especially when one end of the half-wavelength AC transmission line is weakly fed, the protection current at the weak feed end is almost zero, and the single-side current phase selection fails

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