Research On Spectral Analysis Method And Application Of Electric Load Peak-valley Characteristics

With promoting of intelligente interactive mechanism between users in smart grid, injection of large-scale new energy into network and dynamic regulation of economy situation, peak-valley characteristics of electric loads become more complicated. Right now, load factor and peak-valley difference factor or qualitative method-directly observation are often used to characterize load peak-valley characteristics. However, these methods only consider load level of each cross-section point of load curves, which cannot completely describe peak, valley and their fluctuation characters of load curves.At the same time, time variation and volatility of load peak-valley characteristics intensify, which bring outstanding negative influences to power systems, especially the economic problems caused by peak and valley fluctuations of renewable energy. Practices and researches at home and abroad show that demand response mechanism is a necessary way to enhance economy of renewable energy generation. Therefore, expanding load peak-valley characteristics methods, and applying them to demand response decision of renewable energy have theoretical and practical application value.For the above problems, this paper puts forward spectral analysis method to study electric load characteristics. Research on load characteristics is transferred from time domain to frequency domain. Through the method, the time series of electric loads are divided into superposition of periodic components with different amplitude, phase and frequency. The fluctuation situation of load curves can be analyzed more effectively.This paper uses single spectrum analysis method, extracts related indexes, and establishes frequency evaluation model of time-of-use price based on above indexes. Meanwhile, the paper adopts cross spectrum analysis method to research the cycle degeneration of wind power load and all kinds of electric loads, and builds demand response matching analysis model to support healthy development of wind power. The model is based on comparison of frequency domain volatility characters between wind power curve and customer demand curve, and positions user resources in order to promote economic absorbing of wind power. Finally, examples show that, load characteristics model based on spectral analysis can describe peak and valley fluctuation characteristics of load curves conveniently and effectively. The model can be applied to demand response evaluation and match analysis, it promotes the reasonable design of demand response mechanism and improves economy of renewable energy generation.