A method for establishing harmonic model of household electrical appliance load based on measured data

Abstract

The invention discloses a method for establishing harmonic model of household electrical appliance load based on measured data, which comprises the following steps of acquiring measured voltage and current data of household electrical appliance load; performing Fourier analysis on the measured data to obtain the phasor values of each harmonic of voltage and current; obtaining the phasor values ofeach harmonic of voltage and current; establishing the harmonic model of cross frequency admittance matrix of household electrical appliance load; based on the generalized linear complex biased leastsquare method, calculating the parameters of the cross frequency admittance matrix model, and obtaining the cross frequency admittance harmonic model of household appliances by using the obtained voltage and current harmonic phasors as inputs. The method has the advantages of accuracy, rapidity, simplicity and practicability on the basis of no need to know the internal circuit structure and parameters of the household load, and has great significance for ensuring the accurate analysis and evaluation of the harmonic generation situation of the distribution network.

Description

technical field [0001] The invention belongs to the field of load harmonic modeling, in particular to a method for establishing a household appliance load harmonic model based on measured data. Background technique [0002] In today's power system, residential electricity consumption accounts for more than 30% of the total power consumption, and with the development of smart distribution networks, the proportion of residential electricity consumption continues to increase. However, due to the existence of a large number of power electronic devices in household loads, the harmonic current distortion of most household appliances is very serious, and the total harmonic distortion rate of some currents even exceeds 100%. The measured data shows that some residential distribution feeders The total demand distortion rate of harmonic current on the grid can reach 12%, making the residential load a very important type of harmonic source. The resulting harmonics will lead to a serie...

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Problems solved by technology

In the previous analysis, the constant current source model was often used to calculate the harmonic current of the load of household appliances, but the constant current source model simplifies the influence of the supply voltage on the load harmonic current, so that the calculated harmonic current does not follow the change of the supply voltage. Voltage-sensitive harmonic loads can produce large errors

Therefore, it is proposed to use the cross-frequency admittance matrix model to model the harmonics of the household appliance load. However, in the process of solving the parameters of the cross-frequency admittance matrix model by using the ordinary least squares method, there will be a matrix ill-conditioned problem in the calculation process, resulting in The model parameters solved are inaccurate, which affects the modeling accuracy

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