Method and system for measuring power angle of electric power circuit of distribution network

Abstract

The invention discloses a method and a system for measuring a power angle of an electric power circuit of a distribution network, which belong to the technical field of power electronics. The system for measuring the power angle is positioned at a power substation end; a main transformer is connected with main station equipment through a used transformer; and a user transformer at a low-voltage user end is connected with a power angle measurement end. The method comprises the following steps of: controlling the conduction of a silicon controlled rectifier by a signlechip on a low voltage side of the used transformer inside a power substation, and generating a voltage distorted signal when short circuit happens; after a voltage waveform with the distorted signal is received by the user end, extracting a single distorted signal from a network voltage waveform by time domain differential technology, and accumulating a plurality of distorted signals so as to form a synthesized signal; simultaneously, performing time-frequency analysis processing on the synthesized signal by combining Wigner-Ville distribution with short-time Fourier transform, determining the time difference between the distorted signal and a local voltage zero crossing point according to the time distribution condition of power parameters of the synthesized signal, and combining a connection group relation of the transformer so to obtain the power angle of the circuit. The method is low in cost, is easy to operate, is not influenced by the electric power network structure, and is widely used.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a power angle measurement method and a measurement system of a power line of a distribution network. Background technique [0002] In the distribution network, the power angle of the power line is an important parameter of the power system and the main state variable to measure whether the system can run stably. In recent years, the expansion of the distribution network scale and the development of intelligence have put forward stricter requirements for the stable operation of the distribution network, and the power angle of the distribution network is an important parameter of the operation status of the power grid. Detection is extremely important. [0003] At present, there are mainly two methods for measuring the power angle of power lines: [0004] 1) GPS synchronous clock measurement method, as the most important power angle measurement method, the m...

AI Technical Summary

Problems solved by technology

However, in the actual power grid, the line structure and user load are not stable, and the two often change, so it is impossible to test them in advance, and then use the method of formula calculation to obtain the power angle of the line

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