A method for real-time detection of AC current effective value in power grid

Abstract

The invention provides a method for detecting the effective value of power network alternating current in real time. From the point of the structural characteristics of a current limiter, the current instantaneous value and the voltage instantaneous value of a reactor are detected, and the effective value of the power network alternating current is calculated by use of a derivative method. The method for detecting the effective value of the power network alternating current in real time has the advantages that the effective value of the power network alternating current can be calculated only by use of one sampling point, and the interference caused by current derivation in the effective value calculation process is avoided. The method for detecting the effective value of the power network alternating current in real time is high in reliability, good in instantaneity and high in failure judgment speed.

Description

technical field [0001] The invention relates to a method for real-time detection of an effective value of alternating current in a transmission and distribution network, in particular to a method for detecting the effective value of an alternating current in a transmission and distribution network based on an intrinsic signal of a current limiter. Background technique [0002] With the rapid development of the national economy, the society's demand for electricity continues to increase, which drives the continuous development of the power system. The capacity of single machines and power plants, the capacity of substations, and the load of cities and industrial centers continue to increase, which makes the interconnection of power systems , the level of short-circuit current in the power grid at all levels is increasing continuously, and the destructiveness of short-circuit faults to the power system and its connected electrical equipment is also increasing. Moreover, while ...

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Problems solved by technology

These two methods have many sampling points and long time intervals, so it is difficult to realize real-time calculation of effective values

The AC effective value detection methods proposed by Chinese invention patents CN103149415A and CN102539892B all need to solve the effective value of AC current and voltage through multiple sampling points, which is difficult to implement in real time

The literature "A New Method for Quickly Obtaining Voltage RMS and Frequency" (Journal of Beijing Institute of Petrochemical Technology 2007, 15(4)) proposes an iterative method, which needs to pass through three sampling points and multiple high-order powers The effective value can only be obtained by calculation, and the amount of calculation is large, which will bring additional burden to the control chip (such as DSP and single-chip microcomputer, etc.), and it is difficult to meet the real-time performance

The literature "Inverter Three-loop Control Strategy Based on Fast RMS Algorithm" (Journal of PLA University of Science and Technology, 2010, 11(4)) proposes a derivative method to solve the effective value, but the derivative is very susceptible to large distortion due to external interference, which may lead to a large deviation of the effective value of the AC current

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