Single-phase voltage sag rapid detection method

Abstract

The invention discloses a single-phase voltage sag rapid detection method. Firstly, original data such as voltage and phase of a node is monitored; secondly, according to sampling data, u-alpha and u-beta components in an alpha-beta stationary coordinate system are obtained by means of a delay vector construction method; thirdly, a self-adaptive RLS filter is adopted for filtering to obtain a fundamental component; fourthly, alpha-beta-d q transformation is performed to obtain a d-axis direct current component and a q-axis direct current component of the fundamental component in a dq rotatingcoordinate system; finally, the voltage magnitude and phase are calculated according to the d-axis direct current component and the q-axis direct current component. By means of the method, on one hand, noise generated by signal errors and delay structures can be filtered out simultaneously; on the other hand, the influence of alpha-beta-d q transformation on a harmonic wave method is avoided. Finally, the self-adaptive filter is adopted for replacing a traditional low-pass filter, and the better effect of eliminating the condition of large harmonic wave content is achieved. The self-adaptive filter adopts a recursive least square (RLS) algorithm, and the higher initial convergence speed and higher detection accuracy are achieved.

Description

【Technical field】 [0001] The invention belongs to the field of electric power detection and relates to a single-phase voltage sag rapid detection method. 【Background technique】 [0002] In order to achieve the goal of "zero flicker" power supply, a number of safeguard measures have been formulated and gradually implemented based on past guarantee experience, such as a series of differentiated services such as safety assessment and hidden danger investigation for guarantee customers, but the existing guarantee work still exists The following difficulties: [0003] First, the scope of protection is multi-point and wide-ranging. The protection customers are widely distributed, and the protection scope of each protection place is also different. For example, the main protection scope of the conference center includes conference room lighting and audio system, elevator and fire protection system, and the main protection scope of reception hotels includes guest rooms, restaurants...

AI Technical Summary

Problems solved by technology

Due to the diversification of the customer's internal wiring, the existing emergency plan cannot meet all requirements, and it is impossible to ensure that the general emergency power supply device can be quickly connected

Third, the customer does not configure its own power supply

The scope of protection customers and the range of important loads vary with the protection tasks. Most protection customers are temporary important customers. Compared with long-term key protection customers, the protection measures are relatively backward

For such customers, there is a lack of a more general emergency power supply to improve the reliability of power consumption during their temporary guarantee

Fifth, emergency power supplies such as UPS (Uninterruptible Power Supply) have poor functionality

[0009] The 90° delay construction method requires a large delay, and the derivation construction method has overshoot and poor white noise resistance

Although the delay vector construction method has good real-time performance, it will amplify the influence of harmonics and noise

[0010] In the actual distribution network, there will be problems such as distortion and imbalance in the system voltage, and the short-term disturbance and harmonics of the detection waveform will affect the detection accuracy, so it is necessary to add a low-pass filter to the calculation result after dq transformation

The delay characteristics of the low-pass filter will seriously affect the real-time detection performance of the voltage sag, making it difficult to balance the real-time performance and accuracy of the detection with the dq transformation method using the low-pass filter

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