METHOD AND DEVICE FOR SWITCHING ON AND OFF AN ELECTRO-THERMAL INSTALLATION Russian patent published in 2021 - IPC H02J3/12 

FIELD: electrical engineering.

SUBSTANCE: invention is used in the field of electrical engineering for switching on and off thermal-electric installations. A device for switching on and off a thermal-electric installation includes a power transformer, the primary winding of which is connected through the first thyristor starter to the output of a three-phase mains switch, to which the synchronizing input of the thyristor control pulse generator is also connected. The first thyristor starter contains two thyristor switches with natural switching in phases “A” and “C” and a bus for direct connection in a phase “B”. The first and second outputs of the thyristor control pulse generator are respectively connected to the control circuits of the thyristor switches of phases “C” and “A” of the first thyristor starter. When the “Start-Timer” signal is applied to the control input of the thyristor control pulse generator, the thermal-electric installation is switched on for the time set by the timer. Firstly, a pulse is formed for its first output at the moment of the first transition through zero of the phase voltage of the phase “A”. Then, a pulse is formed for its second output at the moment of the transition through zero of the line voltage between phases “B” and “C”, and the thermal-electric installation is switched off by removing the pulses from all the outputs of the thyristor control pulse generator, followed by switching off the mains switch. A battery of cosine capacitors is introduced into the device, which is connected through a second thyristor starter to the output of a three-phase mains switch. The second thyristor starter contains two thyristor switches with natural switching in phases “A” and “C” and a direct connection bus in phase “B”. The thyristor control pulse generator has the third and fourth outputs, which are respectively connected to the control circuits of the thyristor switches of phases “C” and “A” of the second thyristor starter. The pulses at the second and third outputs of the shaper duplicate each other, without having a galvanic connection, and the pulse for the fourth output is formed when the voltage of the phase “A” passes through zero of the next half-period relatively to the pulse at the first output.

EFFECT: increased energy efficiency and energy indicators of the thermal-electric installation in both stationary and dynamic operating modes, as well as a significant reduced duration of the transition process.

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