Relay protection device and method for realizing quick exit of relay protection device

Abstract

The invention provides a relay protection device and a method for realizing a quick exit of the relay protection device. An MOSFET is connected in series between two output contacts of a relay to serve as an exit of the relay protection device; when a sudden change of a current is detected, the relay is immediately triggered to act, a half period is delayed to calculate a current Fourier fundamental wave value, and when a current fundamental wave value is greater than a set action value, the MOSFET is controlled to be switched on so that the relay protection device quickly exits; a signal thata sudden change quantity triggers the relay to act is automatically released after being kept for 500ms; and when the current fundamental wave value is smaller than the set action value after a faultis removed, 100ms is delayed to make the MOSFET be disconnected so that a secondary circuit is disconnected, and arc discharge of an auxiliary contact of a circuit breaker is ensured. In the invention, a simple and practical method is used to realize rapid exit of the relay protection device, and has great significance for removing the fault as soon as possible and preventing accident expansion,and the scheme is convenient to realize, reliable in control and high in practicability.

Description

technical field [0001] The invention relates to the technical field of relay protection, in particular to a relay protection device and a method for realizing rapid exit of the relay protection device. Background technique [0002] When a fault occurs in the power system, in order to avoid the expansion of the accident, it is necessary to remove the fault as soon as possible, which requires the installed relay protection device to be able to remove the fault quickly. At present, most of the outlets of relay protection devices use relay contacts to trigger the secondary tripping circuit. The relay outlet has the characteristics of high withstand voltage and strong anti-interference ability, but the action will be delayed. 4~8ms delay, the maximum delay generally does not exceed 10ms. For 50Hz alternating current, to calculate the accurate protection fundamental wave value, half a cycle of sampling data is generally required, that is, a time window of 10ms is required, so the...

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Problems solved by technology

Chinese patent [201610013025.4] proposes a solution to replace relays with IGBTs, but this solution requires complex anti-interference hardware circuits for IGBTs

Chinese patent [201510126530.5] designed an intelligent switch controller with a fast exit circuit. This solution is mainly used to reduce the transient voltage and inrush current when switching on; in addition, this solution is a separate device and requires CPU, FPGA And CPLD and other controls, the cost is high, and the circuit is complicated

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