New energy station sending-out line pilot protection method based on kanbaala distance

Abstract

The invention discloses a new energy station sending-out line pilot protection method based on a Kanbaala distance, and the method comprises the steps: respectively installing the same line protection devices at two sides of a new energy station sending-out line, independently measuring the three-phase current of the side through each protection device, and obtaining the current information of the opposite side through an optical fiber channel; after inverting the short-circuit current waveform on one side, measuring the waveform similarity of the transient short-circuit current on the two sides of the new energy field station sending-out line by using the Kanbaala distance; based on different waveform similarities of transient short-circuit current on two sides when internal and external faults occur in a new energy station sending-out line, calculating a setting value of a kanbahala distance criterion under the condition of considering a phase angle error and an amplitude error, so as to construct a protection criterion; and identifying a fault type according to the protection criterion, and starting a corresponding protection measure according to the fault type. The method is not influenced by new energy, a control strategy, an operation mode and system capacity, and has the advantages of high reliability and good quickness.

Description

technical field [0001] The invention relates to the technical field of grid-connected protection of new energy power sources, in particular to a method for longitudinal protection of outgoing lines of new energy stations based on Canberra distance. Background technique [0002] With the intensification of energy shortage and environmental pollution, new energy power generation has become one of the main ways to solve this problem. Since large-scale new energy power plants in my country are often far away from the load center, long lines need to be sent to the load center. However, due to the influence of the fault ride-through control strategy of the converter, the short-circuit characteristics of the new energy power supply are different from those of the synchronous generator, showing limited amplitude, frequency offset, controlled phase angle distortion, and non-fundamental frequency and low-order harmonics. Fault characteristics, such as traditional differential protecti...

AI Technical Summary

Problems solved by technology

However, due to the influence of the fault ride-through control strategy of the converter, the short-circuit characteristics of the new energy power supply are different from those of the synchronous generator, showing limited amplitude, frequency offset, controlled phase angle distortion, and non-fundamental frequency and low-order harmonics. The traditional differential protection, which is one of the main protections, faces great challenges due to its fault characteristics, so it is of great significance to carry out the research on the new type of protection for the transmission lines of new energy stations.

[0003] At present, there are few research results on new protection principles using the time-domain transient short-circuit current waveform of the outgoing line. The measurement of waveform similarity mainly includes similarity measure and distance measure. Commonly used similarity measures mainly include Pearson correlation coefficient and cosine similarity. The corresponding protection principles are the longitudinal protection principle based on Pearson correlation coefficient and the new principle of longitudinal protection based on cosine similarity. The protection principle has the risk of performance degradation or even failure to operate correctly; Hausdroff distance is a commonly used distance measurement method, and the corresponding new protection principle is the new principle of longitudinal protection based on Hausdroff distance. However, the essence of Hausdroff distance is the maximum value of the minimum point distance , which is greatly affected by the amplitude of short-circuit current and abnormal data, in new energy power stations with different system operation modes, it is difficult to calculate the protection setting value

It can be seen that the transmission line of the new energy station still lacks a protection scheme with high reliability and good quickness

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