Island type micro-grid energy storage optimized configuration method using wavelet packet decomposition and considering frequency response

A wavelet packet decomposition and frequency response technology, applied in circuit devices, AC network circuits, and AC network load balancing, etc., can solve the problems of poor positioning characteristics and difficult scientific quantification of parameters, reduce costs and ensure long-term effective operation. , the effect of reducing configuration requirements

Inactive Publication Date: 2018-04-20
STATE GRID SHANDONG ELECTRIC POWER +1
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  • Application Information

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Problems solved by technology

However, the proposed hybrid energy storage to stabilize wind power fluctuations does not involve the system's own frequency fluctuations caused by active power imbalance, and the frequency deviation allowed by the island microgrid corresponds to high-frequency and low-amplitude power fluctuations. The frequency fluctuating power is handled by the system's own abs

Method used

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  • Island type micro-grid energy storage optimized configuration method using wavelet packet decomposition and considering frequency response
  • Island type micro-grid energy storage optimized configuration method using wavelet packet decomposition and considering frequency response
  • Island type micro-grid energy storage optimized configuration method using wavelet packet decomposition and considering frequency response

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Experimental program
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comparative approach 3、4

[0166] Comparing schemes 3 and 4, it is found that the consideration of the system's consumption capacity can further reduce the cost of energy storage, which is mainly reflected in the fact that the configuration value of the supercapacitor is lower than that of the traditional method, because the power fluctuations allowed by the system itself are high-frequency, low-amplitude value, this part of the power is stabilized by supercapacitors in Scheme 3, and the application of Scheme 4 method not only reduces the requirements for fast tracking and continuous charging and discharging capabilities of supercapacitors, but also optimizes the power and capacity configuration values, and compared with Scheme 3 The supercapacitor can be continuously charged and discharged for a long time before switching the charge and discharge state once, which reduces the number of charge and discharge transitions. Although the number of switching times in the life cycle of supercapacitors can reach...

example 1

[0168] Changes of energy storage power and SOC before and after fuzzy optimization in Example 1.

[0169] The change curves of energy storage power and SOC before and after fuzzy optimization are as follows: Figure 12 and Figure 13 It can be seen from the power curve that after the fuzzy optimization controller is added, the unbalanced power is still allocated according to the performance characteristics of the power type and energy type energy storage, the medium frequency fluctuation is borne by the super capacitor, and the low frequency fluctuation is borne by the energy storage battery , it can be seen from the SOC curve that the initial SOC of the hybrid energy storage is within the constraints before the fuzzy optimal controller is added, so the SOC of the hybrid energy storage before and after the addition of the fuzzy controller is within the safe range, and there is no overshoot. Occurrence of charging and discharging and power exceeding the limit. The full-day SO...

example 2

[0170] Example 2: Set the daily initial SOC of the energy storage battery to 0.9, which is beyond the constraints of the fully charged state. The SOC change curve of the energy storage battery under the general control strategy and the fuzzy optimal control strategy is as follows: Figure 7 As shown, under the general control strategy, the SOC of the energy storage battery varies greatly, and there are multiple overcharge and overdischarge phenomena. The minimum SOC value under the fuzzy optimization control is 0.3033, and except for the extreme conditions in the initial period, the SOC in the remaining time is 0.3033. Most of the values ​​are in the reasonable interval of [0.3,0.8]. Therefore, the addition of the fuzzy controller can ensure that the energy storage can still be adjusted to a reasonable SOC operating range as soon as possible in the extreme state, reducing the life damage of the energy storage equipment.

[0171] The hybrid energy storage composed of energy sto...

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Abstract

The invention discloses an island type micro-grid energy storage optimized configuration method using wavelet packet decomposition and considering frequency response. Adaptive wavelet packet decomposition serves as a frequency division method of imbalance power, characteristics of an energy-storage battery, a super capacitor and system frequency offset consumption capability are taken into consideration comprehensively, the imbalance power is divided into low-frequency, intermediate-frequency and high-frequency components, the components are stabilized, a mixed energy-storage annular cost value model is established, and an optimal energy-storage configuration result is determined on the basis of the lowest cost. According to the invention, the island micro-grid cost model is established bytaking the cost of an energy-storage system into consideration, configuration of the energy-storage capacity is closely related to the wind abandoning cost and the auxiliary frequency modulation income, and further, a more comprehensive and accurate energy-storing cost model can be established.

Description

technical field [0001] The invention relates to an optimal configuration method for energy storage of an isolated island type microgrid by adopting wavelet packet decomposition and taking frequency response into account. Background technique [0002] In recent years, environmental pollution and energy crisis have attracted more and more people's attention. As a representative of non-polluting renewable energy, wind power has been widely used in power systems. However, for power grids, especially island-type microgrids, due to the randomness and instability of wind power, its massive access will pose great challenges to the reliable operation and frequency stability of the power system. Therefore, it is necessary to take necessary measures to reduce the negative impact of grid-connected wind power on the grid. [0003] Energy storage equipment has the ability to transfer energy within time and space. The use of energy storage technology can effectively stabilize wind power f...

Claims

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Application Information

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IPC IPC(8): H02J3/32H02J3/24
CPCH02J3/24H02J3/32H02J2203/20
Inventor 刘博尹茂林袁帅尹爱辉金谊范永艳张兆笑匡平董新田正军
Owner STATE GRID SHANDONG ELECTRIC POWER
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