A control method to improve the instantaneous frequency stability of low-voltage microgrid
A micro-grid and stability technology, applied in the direction of climate sustainability, reducing/preventing power oscillation, sustainable manufacturing/processing, etc., can solve problems such as frequency oscillation, small frequency variation range, and limited frequency droop gain function range, etc. Achieve the effects of reducing impact, quickly and reasonably distributing, and delaying the frequency change process
Active Publication Date: 2017-05-24
ELECTRIC POWER RES INST OF GUANGDONG POWER GRID
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[0003] However, the range of frequency change specified in the national standard is small when the distribution network is running, which limits the range of the frequency droop gain function, resulting in frequency oscillation when the load changes, causing hidden dangers to the stable operation of the low-voltage microgrid.
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[0053] The present invention will be further described below in conjunction with accompanying drawings and examples.
[0054] The method for controlling the operation of the distributed power supply of the low-voltage microgrid of the present invention, its steps are:
[0055] S1, virtualize the low-voltage microgrid with energy storage unit into a synchronous generator (VSG) model
[0056] Assume: there are n sets of DGs in the low-voltage microgrid, and the interface of DG is the interface of power electronic inverter. k connected to the large power grid, when the switch S k When disconnected, the low-voltage microgrid is in the island operation state, P e is the electromagnetic power, T and T i are the mechanical torque and electromagnetic torque of the virtual synchronous generator model, the unit is N.m, where T=P / ω, J is the moment of inertia of the rotor, the unit is kg.m 2 ,ω * is the reference electrical angular velocity, ω s is the actual electrical angular veloc...
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The invention discloses a regulation and control method for improving transient frequency stability of a low-voltage micro-grid, and provides a control strategy for improving transient frequency response for the problem of transient impact on a system due to quick frequency change caused by disturbance of the low-voltage micro-grid, such as sudden load change. According to the method, on the basis of a virtual synchronous power generator model, an electrical angular speed deviation delta omega and a virtual damping coefficient D are taken as regulating indexes for P / omega droop control in an isolated island running state of the low-voltage micro-grid, the low-voltage micro-grid adopts different droop coefficients under different frequency deviation conditions, the impact on the system caused by transient response of an inverter after disturbance is reduced, and the frequency change rate is delayed; meanwhile, a secondary frequency modulation module for Q-omega and Q / T coordinated control is designed, so that no-deviating frequency regulation can be realized, control reference voltage can be provided for the inverter, and power oscillation is inhibited; the method is suitable for reducing the influence of the frequency on the system due to quick change under the circumstance that the low-voltage micro-grid is disturbed by sudden load change, state transition and the like, and is favorable for stable running of the low-voltage micro-grid.
Description
technical field [0001] The invention relates to a control method for the frequency of a low-voltage micro-grid, in particular to a control method suitable for improving the instantaneous frequency stability of the low-voltage micro-grid in an island operation mode of the low-voltage micro-grid. Background technique [0002] In recent years, with the development of Distributed Generation (DG), low-voltage microgrids containing DG have received more and more attention in the context of increasingly severe energy consumption and environmental problems. How to achieve efficient and stable frequency control in the case of a large number of DGs has become one of the important research directions of low-voltage microgrids in the future. The large-scale penetration of DG in the microgrid makes it difficult for the frequency modulation control strategy of the traditional power system to adapt to the frequency regulation after the low-voltage microgrid is disturbed. In the prior art,...
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IPC IPC(8): H02J3/24
CPCY02P80/14
Inventor 马明盛超徐柏瑜李坦李兰芳李玎王玲邓志刘正富杨洪耕
Owner ELECTRIC POWER RES INST OF GUANGDONG POWER GRID