FIELD: electrical engineering.
SUBSTANCE: according to the method for measuring phase voltages from the side of the system buses and from the power transmission line side, they are converted into digital signals of the same name, from which complex predictive signals of bus voltage and power line voltage are then formed. They form a predictive voltage signal at the contacts of each pole of the switch in the form of a complex signal. Predictive voltage envelope signals are generated at the contacts of the switch poles by determining the modules of the corresponding complex predictive voltage signals and transform them with the help of a maxi-selector into a reference envelope signal. At a given time interval, using the mini-selector, the moment of the onset of the minimum of the predictive signal of the reference envelope is found and it is taken as the reference moment of switching on the switch. In the vicinity of the reference moment of closing the switch, the next two moments of the change in the sign of the imaginary component of the complex predictive voltage signal at the contacts of each pole of the switch are detected. They are taken for the moments of transition of the voltage curve at the contacts of the switch pole through zero, and the moment of re-closing the switch pole near one of them is selected.
EFFECT: reduction of the level of switching overvoltages in the three-phase automatic reclosing cycle.
1 cl, 13 dwg
