Photovoltaic output power smoothing control method and system capable of reducing capacity of energy storage system

Abstract

The invention relates to a photovoltaic output power smoothing control method and system capable of reducing the capacity of an energy storage system. According to the photovoltaic output power smoothing control method and system capable of reducing the capacity of the energy storage system, on the basis of a photovoltaic output power prediction technology, charge and discharge reverse operation is performed on the energy storage system before photovoltaic output power enters predicted surge; charge and discharge forward operation is performed on the energy storage system after the photovoltaic output power reaches the average of the initial value and final value of the predicted surge; the ramp rate of the predicted surge phase is larger than a limited ramp rate; according to the reverseoperation, when the photovoltaic output power increases, the energy storage system is needed to be charged, discharging operation is performed in advance, and when the photovoltaic output power decreases, and the energy storage system needs discharging, charging operation is performed in advance; and the forward operation is opposite to the reverse operation. According to the photovoltaic output power smoothing control method and system capable of reducing the capacity of the energy storage system of the invention, reverse operation and forward operation can be successively performed on the energy storage system in advance before the surge and plunge of the photovoltaic output power occur, and therefore, the required capacity of the energy storage system can be decreased to the greatest extent with the fluctuation of the photovoltaic output power suppressed, and a requirement for the stability of photovoltaic power generation network access can be satisfied.

Description

technical field [0001] The invention relates to a technology in the field of photovoltaics, in particular to a photovoltaic output power smoothing control method and system for reducing the capacity of an energy storage system. Background technique [0002] Photovoltaic power generation has intermittent and fluctuating characteristics, and the intensity of solar radiation determines its output power to a large extent. Therefore, when a large-scale photovoltaic system is connected to the grid, its power fluctuation will bring great challenges to the stable operation of the grid, mainly as follows: [0003] A) PV output power fluctuations in a short period of time may increase the regional control error (ACE) between regions; [0004] B) Large-scale unstable photovoltaic output power will affect the coordinated planning and economic dispatch of the power grid; [0005] C) The transient stability of the power grid is impacted, the power consumption side and the power generati...

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Problems solved by technology

[0015] Considering the high cost and maintenance cost of energy storage equipment at this stage, it is still difficult to equip all photovoltaic power plants with equal-capacity energy storage

[0016] In addition, although under the condition of no energy storage, it is possible to control the ramp rate when the irradiance rises rapidly by actively controlling the power reduction of the photovoltaic system, but the major defect of this solution is that it is difficult for photovoltaic power plants to predict Judging when the irradiance will drop rapidly, so the system is always running in an under-radiation state, resulting in great waste, and the design margin is limited. When the irradiance falls sharply beyond the design margin, this method still cannot effectively increase the ramp rate. control

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