| Voltage sags is one of the most serious problems in power qualityresearch, as it has a very great harm, a wide range of effects and high frequency of occurrence, so it is closely concerned by researchers at home and abroad. Only voltage is interrupted or dips a few cycles, which is also likely to lead to abnormal operation of sensitive electrical equipment, causing huge economic losses and even personal injury. The analysis and suppression measures of voltage sags is a basic work to improve the transient power quality and reduce the frequency of voltage sags, so this has a very important significance. This paper are mainly concerning on voltage sag compensation and suppression measures in area gird, and it specifically as follows:(1) This paper introduces the concept of voltage sags and hazards, then voltage dips caused by large induction motor starting and transformer put into operation is analyzed, and the reasons of voltage dips containing caused by short circuit failure and the impact on the sensitive loads by voltage sag are studied, and the relationship between voltage sag domain and device sensitivity is analyzed.(2) The voltage sag compensation measures are studied. A STATCOM mathematical model is established, based on this study, the work theory, operating range of injection current and control method of STATCOM is illustrated.(3) A model of a domestic oil field power gird is established by PSASP platform, and as an example the suppression measures of voltage sags is analyzed by simulation, the power flow and the voltage dips in various short-circuit conditions of the power grid is calculated, and the grid voltage sag domain is analyzed and calculated by combined with the characteristics of failures.(4) According to the scenario of this power grid, the characteristics of voltage sag is drowned, and current-limiting reactors and STATCOM as two suppression measures are analyzed to verify the suppression effects to the sensitive target bus voltage sags. |
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