Photovoltaic system dual-mode frequency control method based on large disturbance interval recognition

Abstract

The invention relates to the technical field of frequency safety of a power grid, and particularly discloses a photovoltaic system dual-mode frequency control method based on large disturbance interval recognition, which comprises the following steps: firstly, according to different contributions of inertia and damping in each stage of supporting frequency response, selecting to adopt larger inertia control between the disturbance and the lowest point of the frequency after the disturbance occurs; larger frequency damping control is adopted between the lowest point of the frequency and the re-stabilization of the frequency; based on actual power grid frequency historical data, a confidence interval calculation method is utilized to identify a large disturbance interval of a power grid, so that a photovoltaic system dual-mode frequency control action threshold suitable for the power grid is obtained. According to the photovoltaic system dual-mode frequency control method based on large disturbance interval recognition, the frequency supporting effect of dual-mode control can be further improved, and when the inertia level of a power grid changes, the frequency supporting effect can still be maximized through the designed action threshold value.

Description

technical field [0001] The invention relates to the technical field of frequency safety of power grids, in particular to a dual-mode frequency control method for photovoltaic systems based on identification of large disturbance intervals. Background technique [0002] With the leap-forward development of the new energy industry, the proportion of clean power installed capacity has increased significantly. The new energy represented by photovoltaic has the advantages of huge energy and wide distribution. However, there is no direct kinetic energy feedback in the photovoltaic power generation system. Instead, it relies on the inverter control access system of a large number of power electronic components, so it will cause certain damage to the stability of the power grid. influences. Among them, frequency is one of the basic indicators for evaluating power quality. The photovoltaic grid-connected system under conventional power control hardly provides frequency support for t...

AI Technical Summary

Problems solved by technology

[0013]Measure 1 Disadvantage: Adjusting the inertia and damping in real time according to the changing parameters of the power grid has problems such as difficult calculation and high calculation cost, which is difficult to achieve in practical applications

[0014]Measure 2 Disadvantages: In the segmental / hierarchical control method of frequency support, thresholds are often specified to switch between different control modes, but most of them are based on power grid rules It is set as a fixed threshold, without considering the operating characteristics of the power grid and the actual frequency dynamics, and is not applicable to the actual complex power grid

[0015]Measure 3 Disadvantage: The proposed dual-mode coordinated control of virtual inertia and frequency damping of the photovoltaic system does not consider the actual frequency operation status of the power grid, and the steady-state frequency stipulated by the power grid guideline Deviation is used as the action threshold. In the power grid with low inertia level, the problem of frequent switching of control modes is likely to occur. The frequency support effect is not good, and photovoltaic resources cannot be fully utilized.

Images