A method of blocking subsynchronous frequency components in hvdc control loop

Abstract

The invention belongs to the electric power control system technical field and relates to a method for blocking subsynchronous frequency components in an HVDC (high-voltage direct current) control loop. The method includes the following steps that: the torsional vibration frequency of a generator shaft system on which a subsynchronous oscillation occurs is calculated according to generator parameters or is obtained through actual measurement; with the torsional vibration frequency of the generator shaft system adopted as a center frequency, a bandstop filter or band-pass filter is designed; and the designed bandstop filter or the band-pass filter is connected into the control loop of HVDC rectification-side direct-current power or direct current so as to filter out subsynchronous frequency components in the direct-current power or the direct current. The inhibition method provided by the invention is based on the mechanism of the interaction of a large-scale thermal power unit and the HVDC control loop and the research results of damping sensitivity. The method of the invention has the advantages of clear physical concept, simple and convenient calculation, high simplicity and feasibility in project implementation, and convenience in practical application. With the method of the invention adopted, subsynchronous oscillation of the large-scale thermal power unit, which is outputted through HVDC, can be eliminated.

Description

technical field [0001] The invention belongs to the technical field of power system control, and in particular relates to a method for blocking sub-synchronous frequency components in an HVDC control loop. Background technique [0002] Power system subsynchronous oscillation (Subsynchronous Oscillation, SSO) is a dynamic behavior caused by the coupling effect of the dynamic characteristics of mechanical equipment and electrical equipment in the system. With the development of DC transmission technology and its application in high-voltage long-distance transmission of large-scale thermal power units, the problem of subsynchronous oscillation between the shafting of large-scale thermal power units and the HVDC rectifier side and its DC power or DC current control loop has emerged, which is called Subsynchronous Torsional Interaction (SSTI) has attracted extensive attention of electrical engineers and related scholars. The researchers proposed a series of methods to analyze an...

AI Technical Summary

Problems solved by technology

However, the content of the sub-synchronous frequency component in the commutation bus voltage on the rectifier side is relatively small, and it is difficult to extract it in actual engineering, and the suppression effect is limited

In addition, SSDC's suppression of subsynchronous oscillation mainly depends on the correction of the compensation phase in its control link, so a lot of simulation and field testing work is required, and it is very inconvenient to implement

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