Intelligent power supply switch designing method by parallel connection of thyristor and power relay

Abstract

The invention discloses an intelligent power supply switch designing method by parallel connection of a thyristor and a power relay. A pair of nodes leads out from the power relay and are connected at two ends of the thyristor to constitute a switching loop; when a group of an oil pump and a fan is controlled to start, the thyristor is used as a current switch for the control of zero-crossing opening; when the loop is conducted, an intelligent power supply switch controls the power relay to start, the nodes are connected in parallel with a bidirectional thyristor and conducted in the power supply loop, after the power relay starts, the thyristor is controlled to exit, the power relay is controlled to perform long-time action, the connection points are closed for a long time, and the long-time conduction of the power supply loop is ensured; when the group of the oil pump and the fan is controlled to exit, the thyristor is used as the current switch for the control of the zero-crossing opening; at that time, the thyristor and the power relay both belong to the state of parallel connection and conduction to the power supply loop; and the intelligent power supply switch then controls the power relay to exit and not to drive the thyristor, the thyristor performs zero-crossing cutoff of the loop, the power supply loop is cut off, and the oil pump and the fan exit.

Description

technical field [0001] The invention is used in a transformer air-cooling control system and belongs to the application field of power systems. Background technique [0002] The large-scale oil-immersed transformer air-cooled control system includes a central control device and a power switch. The central control device collects the temperature of the transformer oil surface and the load in real time, and automatically controls the power switch to start and stop the oil pump and fan according to the target temperature rise limit, and finally achieves the goal of reducing the temperature of the transformer. The effect of oil temperature. The central control device controls the opening or closing of the weak current relay of the device itself, and the weak current relay starts the intermediate relay for conversion, and finally controls the oil pump and fan switch part of the power circuit. The intermediate relay plays the role of strong current, weak current isolation, DC and...

AI Technical Summary

Problems solved by technology

[0003] The oil temperature of the transformer will change with the change of the ambient temperature and the load, so the central control device will frequently start and stop the oil pump and fan according to the control strategy. Heat Dissipation, Lifespan and Normal Operation of the Grid

Non-contact solid-state relays do not have the problem of contact abnormalities, but solid-state relays pass large currents for a long time, which will cause severe heat generation and easy damage. Once an abnormality occurs, it will affect the heat dissipation, life of the transformer and the normal operation of the power grid

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