Turn-off angle compensation control method for improving stability of LCC-HVDC system under weak receiving end condition

Abstract

The invention discloses a turn-off angle compensation control method for improving stability of an LCC-HVDC system under a weak receiving end condition. The core content of the invention is the turn-off angle compensation control method. The turn-off angle compensation control method is specifically realized by the following steps of: multiplying a q-axis voltage component v<q> output by a phase-locked loop of an inverter station by a compensation coefficient k<gamma c> to obtain a turn-off angle compensation amount gamma<c>; and adding a measured value gamma of the turn-off angle of an inverter valve and the compensation amount gamma<c> of the turn-off angle to obtain a feedback value of a constant turn-off angle controller. Theoretical analysis shows that the pole of the LCC-HVDC system can move towards a left half plane in virtue of the method, so on one hand, the small signal stability of the LCC-HVDC system under the weak receiving end condition is improved, and on the other hand, the feasible regions of parameters of the constant turn-off angle controller and the phase-locked loop of the inverter station are expanded. A simulation result verifies the effectiveness of the method.

Description

technical field [0001] The invention relates to the field of high-voltage direct current transmission, in particular to a shut-off angle compensation control method for improving the stability of an LCC-HVDC system under the condition of a weak receiving end. Background technique [0002] In my country, load centers and primary energy centers are characterized by a reverse distribution from east to west. In order to achieve balanced regional development, it is a more economical and environmentally friendly measure to convert primary energy into electrical energy and transmit it to load centers. LCC-HVDC has the advantages of large transmission capacity, low transmission loss, rapid transmission power adjustment and reversal, and strong asynchronous connection capability. It has the characteristics of flexible control and asynchronous networking, so it is widely used in the field of long-distance large-capacity transmission. . However, with the rapid development of high-volt...

AI Technical Summary

Problems solved by technology

Installing STATCOM on the circulating current bus of the inverter station is one of the measures to improve the stability of the AC and DC system, but the purchase of equipment increases the project investment; reasonable design of the controller parameters and phase-locked loop parameters can avoid the expected instability in the project design stage problems, but it is difficult to adapt to complex and changeable actual working conditions

The application of auxiliary control method is a low-cost, easy-to-implement and effective measure. However, the existing technology has not improved the small-signal stability of the LCC-HVDC system under weak receiver conditions from this aspect.

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