Abstract
This paper discusses the problem associated with accidents in the aerial line (AL) ultra-high voltage (UHV) due to its big length. In lines with a voltage of 500-1150 kV the overwhelming proportion of trips (98%) is caused by single-phase short circuit (SPSC). A substantial portion (70%) single-phase short circuits is erratic arc accidents which can be successfully eliminated in a high-speed auto-reclosing (HSAR) or single-phase auto-reclosing (SPAR). Success single-phase auto-reclosing (SPAR) at liquidation by single-phase short circuit (SPSC), on the one hand, is determined by the characteristics of the secondary arc current, and on the other hand the effectiveness of ways to reduce secondary arc current and recovery voltage development. The minimum dead time, at a HSAR it is usually taken as 0.5 s., at single-phase autoreclosing (SPAR) it depends on the current value of the arc support is in the range of 0.5-3.0 s. The article shows high efficiency of use single-phase auto reclosing (SPAR) at liquidation SPSC in a single-chain AL voltage of 500 kV, the dependence of the bandwidth of transmission in maintaining the dynamic stability from the length of the pause SPAR.
Highlights
The prevailing type of accidents in the aerial line (AL) of ultrahigh voltage (UHV) are single-phase short circuits (SPSC), the proportion of which exceeds 98% [1,2,3,4]
If the minimum no-current pause at automatic high-speed reclosing (AHSR) is usually taken of the order of 0.5 sec, in the case single-phase auto-reclosing (SPAR) it depends on the current value of the arc support is in the range of 0.5-3.0 sec
It is of interest to analyse the nature of dynamic transitions when using AHSR and SPAR of different duration and to assess the level of bandwidth long distance power transmission (LDPT) UHV by the condition of dynamic stability
Summary
The prevailing type of accidents in the aerial line (AL) of ultrahigh voltage (UHV) are single-phase short circuits (SPSC), the proportion of which exceeds 98% [1,2,3,4]. Features of the dynamic transition at the estimated failure can be traced with the help of angular characteristics of a normal mode, mode, SHSC, AR (AHSR or SPAR) and post-accident [5]. It is useful to note that the ratio of the maxima of the angular characteristics in the SHSC in normal mode weakly depend on the circuit parameters, namely the length of the line and the resistance of the starting system (Fig. 2). As in the case of the SHSC, the ratio of the maxima of the angular characteristics in the pause SPAR in the normal regime depends weakly on the parameters of the circuit (Fig. 3). Where КSPAR – is a coefficient varying within a very narrow range, the value of which may be adopted Angular characteristics allow it to perform the dynamic nature of the transition, using the method of squares. Analysis will hold in relation to the scheme in which when transmitting 1000 MW the requirements for static stability (the safety factor is 0.25)
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