Primary frequency modulation control method and system for wind power plant

Abstract

The invention discloses a primary frequency modulation control method and system for a wind power plant. A wind power plant power distribution strategy by using overspeed load shedding control is used. The method comprises the steps that: after a wind power plant receives a system scheduling instruction, power requiring load shedding is calculated according to wind speed information fed back by all wind turbine generators, a power reference value and a load shedding control mode are distributed to all single machines, rotor kinetic energy of the wind turbine generators is stored to the maximumextent, and the frequency dynamic characteristic of a system is improved; and a variable parameter control strategy is utilized in frequency modulation control, the control strategy can ensure that afan can release the maximum standby power in the frequency modulation process, and the recovery speed after frequency drop is increased. It is guaranteed that each fan sufficiently releases standby power in the frequency modulation process, and a frequency steady-state value is effectively increased. The change of an inertia control coefficient can effectively improve the recovery speed of the frequency.

Description

technical field [0001] The invention belongs to the technical field of wind energy control, and in particular relates to a primary frequency modulation control method and system for a wind farm. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] In recent years, renewable energy power generation represented by wind power has developed rapidly in my country, and the grid-connected capacity has increased year by year. By the end of 2017, my country's wind power installed capacity accounted for 35% of the world's total installed capacity, ranking first in the world. [0004] At the same time, the increase in wind power grid-connected capacity has also had a great impact on the safe and stable operation of the power system. Doubly-Fed Induction Generator (Doubly-Fed Induction Generator, DFIG) is the main model of current wind turbines, which ha...

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Problems solved by technology

Literature "Chang-Chien L R, Hung C M, Yin Y C. Dynamic Reserve Allocation for System Contingency by DFIGWind Farms[J]. IEEE Transactions on Power Systems, 2008, 23(2):729-736." and "Fan Guannan, Liu Jizhen ,Meng Hongmin, et al.Primary frequency regulation strategy of wind farm under the condition of power grid load limit[J]. Power Grid Technology, 2016,40(7):2030-2037."Relevant research has been done on the active power distribution and frequency regulation control strategy of wind farm In terms of power distribution, the high-speed wind turbines undertake more frequency modulation power. In terms of frequency control, a combination of load shedding control and droop control is adopted. The droop coefficient is set according to the principle of using a larger droop coefficient for high-wind speed fans, but the droop coefficient Given that the specific situation of the current fan power load reduction is not considered, it is likely that the parameter is too small and the load reduction power cannot be fully released, or the parameter is too large and the fan power is too large to quit frequency regulation.

It can be seen that most of the current research has a single form of power allocation strategy, and the tuning of frequency modulation parameters cannot be well combined with the working conditions of the wind turbine and the actual needs of the power grid.

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