Line protection method for multi-energy system based on waveform difference characteristics

Abstract

The invention discloses a multi-energy system line protection method based on waveform difference characteristics. By measuring the current on both sides of the protected line, the positive sequence current fault component on both sides is calculated, and the positive sequence current fault component on both sides is extracted by a peak-valley detection operator. The initial peak value and its corresponding time are used to distinguish the internal and external faults of the area. The invention ensures that the protection devices on both sides of the protected line in the multi-energy system can quickly and accurately identify faults inside and outside the zone, and is suitable for multi-energy systems with two structures, ring and radial, with low communication requirements and easy setting of protection thresholds. Has good selectivity and sensitivity.

Description

technical field [0001] The invention belongs to the technical field of electric power system relay protection, and relates to a multi-energy system line protection method based on waveform difference characteristics. Background technique [0002] The multi-energy system is a small-scale power generation and distribution system that organically integrates distributed micro-sources, loads, energy storage devices, and power electronic converters. It can operate in two modes of grid-connected or isolated, which can effectively reduce intermittent distribution. It is one of the most effective ways for distributed micro-sources to connect to the distribution network to minimize the adverse effects of distributed power sources on the distribution network and to maximize the use of distributed power sources. As an important link between the large power grid and distributed micro-sources, the safe and stable operation of the multi-energy system is the primary guarantee for its energy...

AI Technical Summary

Problems solved by technology

Among them, single-ended protection does not require communication, and only needs to use local information for fault detection, mainly including fault characteristics such as current amplitude, harmonics, and transient components. It is simple to implement, but it is difficult to adapt to multi-energy systems with variable topologies, and There is a protection dead zone and the selectivity is poor; compared with single-ended protection, double-ended protection has good selectivity and requires communication. The instantaneous current difference, initial traveling wave polarity and time information on both sides of the protected line are often used , direction difference or impedance difference and other fault characteristics, the hardware requirements for the information acquisition unit or communication are relatively high, and it is difficult to realize

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