Voltage sag detection method for cascade type electric energy quality comprehensive treatment device

Abstract

The invention provides a voltage sag detection method for a cascade type electric energy quality comprehensive treatment device. The method comprises the following steps: 1, acquiring a three-phase phase voltage instantaneous value signal of a power grid; 2, calculating a power grid voltage phase angle and a voltage component of the three-phase phase voltage of the power grid in an alpha-beta rotating coordinate system according to the instantaneous value signal of the three-phase phase voltage of the power grid; 3, calculating a voltage component under a positive and negative sequence dq coordinate system according to a result obtained by calculation in the step 1, and obtaining positive and negative sequence fundamental wave components through positive and negative sequence decoupling and high-frequency filtering; 4, according to the positive sequence fundamental component and the negative sequence fundamental component, calculating negative sequence fundamental component angle characteristic quantity and three-phase power grid voltage positive sequence fundamental component amplitude modulus length, and obtaining a characteristic value based on a voltage sag voltage threshold value; and 5, according to the negative sequence fundamental component angle characteristic quantity, the three-phase power grid voltage positive sequence fundamental component amplitude modulus length and the characteristic value, determining the power grid voltage sag and the type thereof. The method can be realized by software, the algorithm is simple, the effect is obvious, and engineering application is facilitated.

Description

Technical field [0001] Technical Field The present invention relates to power electronic control device, in particular a cascade for voltage control power quality detection means sag. Background technique [0002] Currently, with the rapid development of industrial automation technology, put into operation in a wide variety of sensitive user load, as well as a large number of new technology products in the high standard of living in a wide range of applications, power quality more stringent. [0003] The sensitivity of the sensitive load is very high power quality, several to several tens of cycles voltage mutations cause abnormal operation of the load-sensitive device, the user-side electrical equipment to produce a chain reaction, resulting in enormous direct and indirect Economic losses. Wherein the voltage sag event is one of the most prominent power quality problems and the most prone to the types of problems. [0004] Therefore, rapid and accurate detection of power supply ...

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Problems solved by technology

[0003] These sensitive loads are very sensitive to power quality, and voltage mutations of several to dozens of cycles will cause abnormal operation of

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