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To solve the problem that voltage and frequency fluctuations during the switching process of grid-connected and island of microgrid with multi-micro source, this paper researches the structure and characteristics of doubly fed induction generator (DFIG), micro gas turbine and battery, then proposes a novel integrated control strategy of multi-micro source microgrid. The proposed method utilizes different control methods are adopted for multi-micro source. Make the micro source have a stable output in grid-connected operation state. Maintaining the micro source has a stable output during switching process of grid-connected and island, and keeping a stable and reliable voltage and frequency in island operation state. Ensure the voltage frequency stability during the switching mode of the microgrid operation mode. This paper simulates the microgrid system by using Matlab/Simulink simulation software. And the simulation results verify that the novel integrated control strategy for multi-micro source microgrid is stable and can smoothly transition when the microgrid operating state is switched.

In view of the power quality disturbance detection problem, a power quality disturbance detection algorithm combining adaptive threshold and multi-resolution singular value decomposition packet is proposed with current signal as the research object. The multi- resolution SVD packets decomposition is used on the current signal. The disturbance can be detected according to the characteristics of the decomposed high frequency components, and combine with the adaptive threshold value to determine whether disturbance occurs. The algorithm is verified by simulation, and the simulation results show that this algorithm has good anti-noise capability, and can realize fast and accurate positioning of disturbance signals.In view of the power quality disturbance detection problem, a power quality disturbance detection algorithm combining adaptive threshold and multi-resolution singular value decomposition packet is proposed with current signal as the research object. The multi- resolution SVD packets decomposition is used on the current signal. The disturbance can be detected according to the characteristics of the decomposed high frequency components, and combine with the adaptive threshold value to determine whether disturbance occurs. The algorithm is verified by simulation, and the simulation results show that this algorithm has good anti-noise capability, and can realize fast and accurate positioning of disturbance signals.

In recent years, Using renewable energy is the trend of world energy development. The volatility of renewable energy is increasing along with its installed capacity magnfying, resulting in abandoned wind, light and other issues, impacting renewable energy consumption seriously. In order to solve this problem, trading the abandoned wind and light and using them supply based on power market means under the existing scheduling system can effectively promote the elimination of renewable energy, reduce the consumption of fossil fuels such as coal, and protect the environment. China's renewable energy has been growing rapidly. However, the phenomena of wind and solar power curtailment because of the lack of the peak load regulating capacity in power system, CHP(Combined Heat and Power)operating on the principle of power determined by heat”, the mismatch between installed capacity of renewable energy and the demand for electricity, the lack of local consumption capacity, the unbalance between renewable energy power generation and grid construction, and the transmission capacity restrictions, still exist, which brings serious challenge to power system economic operation. The randomness, variability and uncertainty of renewable energy power generation further increase the difficulty of grid connected consumption. To solve the problem of renewable energy consumption, measures should be taken from the aspects of generation, grid, load, storage, power market and other areas. Focusing on the issue of renewable energy consumption, the following research was carried out: considering using the multi-energy complementary strategy improve the ability of renewable energy consumption, the integrated electricity-heat energy system which is coupled by CHP units and power-to-heat equipment is researched and a combined heat and power dispatch considering the energy storage characteristics of the heating network is formulated. In the optimal dispatch model which comprehensively takes into account the complementary characteristics of electrical system and the system-temperature dynamics equation considering transmission delay in the pipelines is used to reflect the energy storage characteristics of the heating network. In addition, the transmission loss in the pipelines, the user flexible demand for thermal energy and other heating network constraints are taken into account in the model. The simulation indicates that the proposed model can coordinate the generation, grid, load in the system and realize optimal matching of heat and power thus improve the renewable energy consumption ability.