Process for real time recognizing voltage stability of electrified wire netting trough recognizing weak links of electric network

Abstract

The present invention relates to a method of identifying the voltage stability of power grid in real time via figuring out the weak links of power grid; and uses a basic line voltage stability index BLSI or an extended line voltage stability index ELSI which is improved on the basis of the BLSI index to monitor, identify and judge power grid. The steps of identifying are as follows. Firstly, the requisite real-time date can be obtained via a PMU system or SCADA and EMS; Secondly, useless measurements get filtrated; thirdly, the parameters of the line are reassessed in real time if necessary in a given time interval; fourthly, a BLSI index or ELSI index is used to identify the weak links of the system; lastly, the system emergency protection control is started up to avoid the breakdown of system voltage at the BLSI value or ELSI value which is the weakest link that leads to voltage breakdown. The present invention has the advantages of identifying voltage invariability of the system in real time and weak lines and weak links that cause voltage breakdown of the system; and automatically dealing with actual loading properties relevant to voltage or frequency.

Description

technical field [0001] The invention relates to a method for identifying and judging the voltage stability of a power system (grid), in particular to a real-time quantity measurement or state estimation of the voltage and current (or power) phasors at both ends of the line to identify and judge the power in real time. method for voltage stability of the system. Background technique [0002] Voltage stability has long been a matter of great concern to power companies. In recent years, voltage instability accidents have occurred in different power systems all over the world, and have caused major blackouts in the system. Therefore, the voltage stability problem has become one of the hot spots at home and abroad. So far, a lot of research has been done on voltage stability evaluation methods, but most of the methods can only be applied to off-line calculations [1-16] (Note: In the process of developing the present invention, the inventor has conducted a large number of Retrie...

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Problems solved by technology

If the two system states are too far apart, this assumption is obviously not valid; on the contrary, if they are too close, it may cause a large calculation error when estimating Thevenin equivalent impedance, this shortcoming leads to its practical Difficulty and imprecision in application

[0012] · The proposed method cannot identify any erroneous or invalid measurement data

Indicators are useless and meaningless if any voltage or current measurements are incorrect or have large errors

However, in any measurement system, it is impossible to completely avoid the situation of invalid measurement data

[0013] Although these indicators can identify weak nodes, they cannot identify weak grid lines that cause system voltage collapse

[0014] ·This method cannot be applied to the SCADA measurement data collection system and EMS energy management system of the existing control center

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