Method for constructing harmonic wave impedance characteristic function

Abstract

The invention relates to a method for constructing a harmonic wave impedance characteristic function. The method comprises the steps that voltages at a common coupling point of distributed grid-connection power generation systems and currents connected into the distributed grid-connection power generation systems are collected; the fundamental wave impedance amplitude |Z1| at the common coupling point of the distributed grid-connection power generation systems and the harmonic wave impedance amplitude |Zk| at the common coupling point of the distributed grid-connection power generation systems are calculated, wherein k is a natural number larger than 1 and represents a corresponding harmonic order; according to a function (please see the specific formula in the specification), the harmonic wave impedance characteristic quantity phi (k) at the common coupling point is obtained. The method for constructing the harmonic wave impedance characteristic function is capable of obtaining the characteristic quantity for reflecting island load characteristics and lowering island error judgment occurring when grid frequency or voltages change or the multiple grid-connection power generation systems operate in parallel, and is wide in application range.

Description

technical field [0001] The invention relates to a data processing technology for extracting characteristic quantities from parameters in a distributed grid-connected power generation system, in particular to a method for constructing harmonic impedance characteristic functions. Background technique [0002] Distributed generation refers to the configuration of smaller generator sets (generally less than 30MW) at the user site or near the power consumption site to meet the needs of specific users, support the economic operation of the existing distribution network, or meet both aspects at the same time requirements. With the continuous reduction of global fuel energy and its increasingly serious environmental hazards, the distributed power generation system based on renewable energy has been greatly developed. However, there are still many core technical problems to be solved urgently in the distributed grid-connected power generation system, especially the detection of isla...

AI Technical Summary

Problems solved by technology

However, the existing characteristic quantities for distinguishing between islands and non-islands, such as the effective value of voltage at the common coupling point, frequency, frequency change rate, voltage phase, etc., do not reflect the characteristics of the island load well, so when the grid frequency, voltage When changes occur or multiple distributed grid-connected power generation systems run in parallel, the system is prone to island misjudgment

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