A new energy grid connection method

Abstract

The invention relates to a new energy grid-connected method. By constructing a new energy grid-connected topological structure, the new energy unit is connected to the convergence bus through the new energy unit grid-connected inverter and the new energy unit step-up transformer on the line; the convergence bus There are two branches on the top: one branch is set step-down transformer, synchronous motor, synchronous generator, MGP grid-connected step-up transformer and MGP grid-connected switch to form MGP grid-connected loop, new energy unit, synchronous motor and synchronous The generator constitutes the MGP system; the other branch forms a new energy direct grid-connected loop through a direct grid-connected step-up transformer and a direct grid-connected switch. By detecting the relationship between the overall active power emitted by new energy and the rated capacity of the MGP system, the active power is allocated reasonably, and the stability of large-scale distributed power access to the grid is improved. The present invention uses a real synchronous machine, so the inertia and damping characteristics of the motor itself can be relied on to improve the anti-disturbance capability of the new energy side.

Description

Technical field [0001] The present invention relates to the field of new energy grid-connected technology, specifically to a new energy grid-connected method. Background [0002] New energy utilization forms such as wind power and photovoltaic power generation are important means to achieve "two alternatives", promote energy conservation and emission reduction, and build a global energy Internet. Data studies show 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 the proportion of new installed capacity in China was 22%, of which the installed capacity of wind power and photovoltaics was 184 million kilowatts and 174 million kilowatts, accounting for 18.8% of China's total power supply, exceeding the capacity of hydroelectric assemblers for the first time. Vigorously developing distributed generation is of great significance in improving the economics of power grid operation, optimizing the operation m...

AI Technical Summary

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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