Novel new energy grid-connected topological structure and method

Abstract

The invention relates to a novel new energy grid-connected topological structure and method. The topological structure is characterized in that a new energy unit is converged into a convergence bus through a new energy unit grid-connected inverter and a new energy unit boosting transformer on a line; the convergence bus is divided into two branches; one branch is sequentially provided with a step-down transformer, a synchronous motor, a synchronous generator, an MGP grid-connected boosting transformer and an MGP grid-connected switch to form an MGP grid-connected loop, and the new energy unit,the synchronous motor and the synchronous generator form an MGP system; and the other branch forms a new energy direct grid-connected loop through a direct grid-connected boosting transformer and a direct grid-connected switch. By detecting the size relation between the active power integrally emitted by the new energy and the rated capacity of the MGP system, the active power is reasonably distributed, and the stability of the large-scale distributed power supply connected to the power grid is improved. According to the system, a real synchronous machine is adopted, so that the disturbance rejection capability of a new energy side can be improved by virtue of inertia and damping characteristics of the motor.

Description

technical field [0001] The invention relates to the technical field of new energy grid connection, in particular to a novel new energy grid connection topology structure and method. Background technique [0002] New energy utilization forms such as wind power and photovoltaic power generation are important means to realize "two substitutions", promote energy conservation and emission reduction, and build a global energy Internet. Data research shows that as of the end of 2018, the proportion of new installed capacity of wind power and photovoltaics in the world was 24.8%, and that of new installed capacity in my country was 22%. 18.8% of the total power supply exceeded the installed capacity of hydropower for the first time. Vigorously developing distributed power generation is of great significance in improving the economics of power grid operation, optimizing the operation mode of the power system, and building an environment-friendly power system. [0003] In general, di...

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Problems solved by technology

Compared with the traditional synchronous generator, it has the advantages of flexible control and quick response, but there are also shortcomings such as obvious nonlinear characteristics, lack of inertia, insufficient short-circuit capacity support, and high harmonic content, which is easy to generate oscillation.

As the penetration rate of new energy power generation continues to increase, a large number of grid-connected power electronic inverters will appear in the power system, while the installed capacity of traditional synchronous generators will decrease, resulting in a reduction in the rotating reserve capacity and moment of inertia of the power system

In addition, the grid-connected control strategies of distributed power generation are different, and its output power has the characteristics of fluctuation and uncertainty, so it is difficult to meet the operating characteristics of frequency modulation and voltage regulation required by the power system, thus bringing a negative impact on the safe and stable operation of the power grid. here comes a serious challenge

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