A Dynamic Tracking-Based Evaluation Method for Voltage Weak Areas of DC Receiver AC System

Abstract

The invention discloses a dynamic tracking-based method for assessing voltage weak areas of a DC receiving-end AC system, including steps: 1. Based on the WAMS system, extracting voltage fluctuation waveforms of recent abnormal fluctuation information and performing statistics, determining areas where voltage jitter often occurs and Calculate the abnormal fluctuation level coefficient C of its regional voltage 1 . 2. In the normal operation mode, calculate the voltage stability level coefficient C of the DC receiving end system 2 . 3. Calculate the voltage stability level coefficient C of the receiving end system when the line fault is disconnected 3 ; 4. Sorting the line faults. 5. Insert the C 1 、C 2 、C 3 Carrying out synthesis to form a superposition formula, the voltage stability level of each sub-area is given. 0≤R≤0.03 is a serious danger area; 0.03≤R≤0.5 is a general danger area; The method of the invention can realize the danger level division of the weak area of ​​voltage stability level, can quickly evaluate the voltage instability risk area of ​​the DC system receiving end power grid after a fault, has good practicability, small workload, and can deal with various hidden trouble problems.

Description

technical field [0001] The invention belongs to the technical field of power system security and stability analysis, and in particular relates to a dynamic tracking-based method for assessing voltage weak regions of an AC system at a DC receiving end. Background technique [0002] At present, China's power grid has formed a North China-Central China AC interconnected power grid, and the East China Power Grid operates in an isolated grid, and is connected to the North China-Central China Power Grid through a DC system. According to the plan, China will build dozens of UHV DC projects in the next 10-20 years, and gradually form a UHV AC-DC hybrid power grid to supply power to the central and eastern load centers through UHV DC and AC systems. Conventional HVDC transmission systems require sufficient commutation voltage from the AC system at the receiving end, and will absorb a large amount of reactive power from the AC system after commutation failure occurs. After multiple DC...

AI Technical Summary

Problems solved by technology

[0004] For the AC / DC hybrid fed into the receiving end grid, the more serious safety and stability problem is the possible cascading failure of the AC / DC system, that is, the failure of the AC system may cause the continuous commutation failure of the DC system, which in turn leads to DC blocking and greater power transfer to the AC channel, triggering a cascading power grid collapse accident

The current research methods for this problem are still single. In engineering, the time domain simulation method is mainly used. Through the transient stability simulation of various AC and DC system fault combinations, it is evaluated whether it will cause the continuous commutation failure of the DC system, and then cause more damage. It is a serious cascading failure; however, this method faces problems such as heavy workload and difficulty in enumerating potential failures

In addition, some studies have been carried out at home and abroad on the formation mechanism and evolution process of cascading faults, and analysis methods such as power flow transfer evaluation after faults and small-world characteristics of power grids have been proposed, which have promoted the development of cascading fault set construction technology; but the current Research methods mostly focus on theoretical analysis or summary of operating experience. How to propose an effective and practical method of cascading fault set construction in combination with the actual situation of the power grid still needs further research

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