A Method for Evaluating Voltage Weak Areas of AC Systems at DC Receiving Terminals

Abstract

The invention discloses a voltage weak region evaluation method for an alternating current system at a direct current receiving end. The voltage weak region evaluation method comprises the steps of calculating the sensitivity of an alternating current node voltage relative to direct current falling point reactive power by taking a load static voltage characteristic-considered alternating current direct current power system power flow equation as the basis; next, based on a continuous power flow method, calculating the static voltage stability margin of a near region alternating current node of the load static voltage characteristic-considered direct current falling point; and finally, obtaining the voltage weak region evaluation index by comprehensively considering the two indexes. According to the method, in the voltage weak region evaluation process, the reactive-voltage sensitivity and static voltage stability margin are taken into comprehensive consideration, so that the indexes are more all-around; and meanwhile, the load static voltage characteristic is taken into consideration in the sensitivity and static voltage stability margin calculation, so that the obtained result can better reflect the operation law of the system, thereby promoting guidance in subsequent control strategy formulating.

Description

technical field [0001] The invention belongs to the field of analysis and control of an AC-DC interconnected power system, and in particular relates to a method for assessing a weak voltage region of a DC receiving-end AC system. Background technique [0002] Usually, the load of the AC system near the high-power DC landing point is heavy. When the voltage support capacity of the AC system is insufficient, it is easy to cause a fault in the DC system, and even cause the fault to spread to the entire network, affecting the safe and stable operation of the system. Therefore, only by determining the voltage weak link of the AC system in the vicinity of the DC landing point can the control be guided reasonably. [0003] Existing methods generally only consider reactive power-voltage sensitivity or static voltage stability margin when evaluating power system voltage weak regions. Compared with existing methods, the indicators in this paper are more comprehensive and the results ...

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Problems solved by technology

[0004] In addition, the existing methods usually regard the load as a constant power load when calculating reactive power-voltage sensitivity or static voltage stability, and do not take into account the static voltage characteristics of the load. The results obtained may be out of touch with the actual situation, which is not conducive to guiding subsequent control strategies formulation

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