Inverter grid connected type power source impedance measurement model optimization method under the condition of external disturbance signals

Abstract

The invention belongs to the new energy generating grid connected technology field of an electric power system and particularly relates to an inverter grid connected type power source impedance measurement model optimization method under the condition of external disturbance signals. The method is characterized by comprising steps that, dynamic channels through which the external disturbance signals enter an inverter and conversion rulers are acquired through analysis according to inverter on-ff rules; the signal channels are classified, for each type of the channels, subsequent channels after the signals passing through the inverter are further analyzed; according to the signal channel analysis result, external impedance measurement characteristics of an inverter grid connected type power source are solved through conclusion and equivalence; on the basis of the external impedance measurement characteristics, conversion from dynamic time-variable impedance to constant state impedance is carried out. The method is not limited by generator types, inverter grid connected requirement is only necessary, operation conditions and different control strategies are further not restrained, a voltage source type PWM inverter is only satisfied, principle universality is realized, the method is suitable for complex multi-machine clustering, and the method has high precision.

Description

technical field [0001] The invention belongs to the technical field of grid-connected new energy power generation in electric power systems, and in particular relates to an impedance model optimization method for inverter-grid-connected power supply measurement under external disturbance signals. Background technique [0002] The grid connection of distributed new energy power sources brings new problems to the control and protection of power systems. In addition to traditional problems such as power flow distribution, stability, peak regulation and frequency regulation, isolated islands have also become an important issue for distributed new energy power generation systems. Problem islands are an important problem in distributed generation systems. The so-called island phenomenon refers to the state in which a part of the power grid including loads and power sources continues to operate in isolation after being separated from the main grid. Islands are divided into planned...

AI Technical Summary

Problems solved by technology

In the current method, it is usually assumed that the distributed power supply is a synchronous machine, and the equivalent impedance of the system under external disturbance is easy to obtain

However, considering that most distributed power sources are connected to the grid with inverters in actual operation, this equivalent method has theoretical defects and is difficult to meet the requirements of practical applications.

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