A Method for Improving the Static Voltage Stability of AC-DC Hybrid Power Grid

Abstract

The invention provides a method for improving the static voltage stability of an AC-DC hybrid power grid. The method comprises the following steps: establishing a peak load mode simulation model of the AC-DC hybrid power grid; finding out a weakest voltage node and a second-weakestvoltage node; adjusting load distribution so as to obtain the comprehensive sensitivity of the static voltage stability of the weakest voltage node; calculating the comprehensive sensitivity of the static voltage stability and reactive power compensation requirements of the weak voltage node by adopting PSD (Phase Sensitive Demodulator) software, and additionally arranging reactive power compensation equipment; and calculating the comprehensive sensitivity of the static voltage stability and the static voltage stability margin of the weak voltage node after the reactive power compensation equipment is additionally arranged by adopting the PSD software, and comparing the static voltage stability of the AC-DC hybrid power grid before and after the reactive power compensation equipment is additionally arranged. The method disclosed by the invention has the advantages of being high in operability, comprehensive in considered factor, reasonable in scheme, economic and feasible in technology, clear in calculation result, high in practical value, good in market prospect and the like and can be used for specifically guiding planning and operating of the power grid and the like.

Description

technical field [0001] The invention relates to a method for improving voltage stability, in particular to a method for improving static voltage stability of an AC / DC hybrid grid. Background technique [0002] At present, the indicators for evaluating static voltage stability mainly include voltage amplitude indicators, various sensitivity indicators, power margin indicators, minimum singular value indicators, and eigenvalue indicators. The voltage amplitude index is very intuitive, but due to the nonlinear characteristics of voltage changes, the voltage amplitude cannot reflect the static voltage stability level and reactive power support capability of the system. The solution process of various sensitivity indicators does not reflect the transition process of the actual system from the operating point to the critical point, and does not consider the influence of various restrictive factors such as load characteristics and generator reactive power constraints. The physical ...

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Problems solved by technology

The active power margin is very intuitive, but it has certain uncertainties due to the influence of load growth and different combinations of power generation output; the reactive power margin is strongly related to the active load capacity of the system, and the results are highly deterministic and of reference value High, but for the weakly connected power grid structure, the reactive power margin cannot directly reflect the voltage stability level of the research area

The minimum singular value index is similar to the eigenvalue index and has a clear physical meaning, but the linearity is not good, and the amount of calculation is large. Moreover, for generators close to active power constraints and reactive power constraints, the change law of the minimum singular value index and eigenvalue index is different. Stability, and voltage stability usually needs to be concerned about the operating state close to active or reactive power constraints, thus limiting its application

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