Calculating and analyzing method for resonance characteristics of direct current circuit of high-voltage direct current power transmission

Abstract

The invention relates to a calculating and analyzing method for resonance characteristics of a direct current circuit of high-voltage direct current power transmission. The calculating and analyzing method for the resonance characteristics of the direct current circuit of the high-voltage direct current power transmission comprises the following steps of (1) setting up a direct current circuit resonance model, wherein according to a direct current system needing to be researched, system parameters are input in an EMTDC simulation model, a direct current circuit equivalent simplified simulation model is established; (2) setting a unit surge voltage source; (3) determining working conditions of researches; (4) carrying out time-domain simulation; (5) analyzing impedance characteristics; (6) analyzing resonance characteristics; (7) verifying power frequency and secondary power frequency; (8) carrying out simulation verification on the influences of failures and disturbances on direct current circuit resonance; (9) analyzing the calculation conclusion. According to the calculating and analyzing method for the resonance characteristics of the direct current circuit of the high-voltage direct current power transmission, the direct current circuit impedance under different frequencies can be calculated accurately, the response conditions of the power frequency and the response conditions of the secondary power frequency can be analyzed more accurately, and the calculating and analyzing method has strong operability and engineering practicability.

Description

technical field [0001] The invention relates to a method in the technical field of high-voltage direct current transmission in electric power systems, in particular to a method for calculating and analyzing resonance characteristics of a high-voltage direct current transmission direct current circuit using a unit impulse voltage source. Background technique [0002] In the DC transmission system, due to the mutual influence between the AC and DC systems, the disturbance on either side may cause the system to oscillate. And when the natural resonant frequency of the DC link is at the fundamental or 2nd harmonic frequency, the oscillation caused by the disturbance may cause damage to the equipment. For DC projects with short transmission lines, the resonant frequency is generally far away from the fundamental frequency and the secondary frequency, so there is generally no special consideration for resonance issues, but the 500kV and above UHV DC project lines are as long as on...

AI Technical Summary

Problems solved by technology

Due to the non-linear element of the converter in the DC transmission system, the resonance characteristics of the DC circuit cannot be calculated by the conventional frequency sweep method.

Earlier, when modeling, the simplest way to simulate the converter was to use 1 internal inductance to represent the 6-pulse converter. This approach was obtained by assuming that the AC bus of the converter station was connected to the infinite system, and In fact, the short-circuit ratio of the AC system is not infinite, therefore, using the above formula to simulate the converter and then calculate the resonance characteristics of the DC circuit does not match the actual situation

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