Broadband harmonic collection and measurement system based on multi-band double-way filtering and broadband harmonic collection and measurement method based on the same

Abstract

The invention provides a broadband harmonic collection and measurement system based on multi-band double-way filtering and a broadband harmonic collection and measurement method based on the multi-band double-way filtering. According to the problems that an ordinary harmonic measurement instrument is narrow in measurement band, big in measurement error and the same, a double-way multi-band filtering circuit and a double alterative current / direct current (AD) panel high-frequency sampling circuit. According to the low-band harmonic and high-band harmonic, different filtering circuits and sampling frequencies are selected for signal sampling. The broadband harmonic collection and measurement method is capable of measuring wider-band harmonic, is capable of guaranteeing the measurement accuracy and improving the calculation efficiency by selecting different sampling frequencies according to different applicable bands, and provides an effective method for achieving a high-performance harmonic measurement device.

Description

technical field [0001] The invention belongs to the technical field of power systems, and in particular relates to a wide-band harmonic acquisition and measurement system and method based on frequency-divided dual-path filtering. Background technique [0002] With the continuous advancement of the global industrialization process, the application of power electronic devices is becoming more and more extensive, and the harmonic pollution in the power grid is also becoming more and more serious. The appearance of harmonics deteriorates the environment in which electrical equipment is located, causes various failures and accidents of equipment, and also brings harm to surrounding communication systems and equipment outside the public power grid. In addition, harmonics will also generate additional harmonic losses, reduce power generation and transmission efficiency, and may cause local series or parallel resonance, resulting in malfunctions of relay protection and automatic dev...

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Problems solved by technology

[0004] Due to the characteristics of nonlinearity, randomness, distribution, non-stationarity and negative influence factors of harmonics, it is very difficult to measure harmonics accurately

At present, the measurable frequency range of various harmonic measuring devices is generally lower than 2.5kHz. Most harmonic meters and power quality monitoring devices can only measure harmonics within the 50th power frequency, which cannot meet the harmonics of modern power grids. monitoring needs

When performing broadband harmonic measurement, it is necessary to add a bandpass filter to the input signal. Since the frequency bandwidth covered by the harmonic is very wide (from the fundamental frequency to 9kHz), the passband range of the filter is subject to the active The bandwidth of the device is limited. If the passband is too wide, the measurement signal will have a large error, which will seriously affect the measurement accuracy.

Therefore, harmonic measurement in high frequency and wide frequency range remains a challenge

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