US 11,695,267 B2 · Protective relay and method for detecting disconnection of protective relay

Abstract

The present disclosure relates to a protective relay detecting disconnection in a circuit comprising a disconnection detection unit including a plurality of nodes connected to both ends of an output of a transformation unit, a reference voltage generation unit forming a reference voltage, and a plurality of resistors forming a voltage dividing resistor and connecting the plurality of nodes and the reference voltage generation unit; a sensing voltage generation unit applying a voltage for forming a predetermined voltage difference with respect to the reference voltage; and a disconnection determination unit connected to a first node, in which the magnitude of a voltage signal applied by the voltage dividing resistor varies depending on whether at least one of the transformation unit and the circuit connected to the transformation unit is disconnected, and detecting whether at least one of the transformation unit and the circuit connected to the transformation unit is disconnected.

Claims23

Dependent claims

A protective relay that detects whether a transformation unit and a circuit connected to the transformation unit are disconnected, the protective relay comprising:

a disconnection detection unit comprising a plurality of nodes connected to both output ends of the transformation unit, a reference voltage generation unit that defines a reference voltage, and a plurality of resistors constituting a voltage dividing resistor and connecting between the plurality of nodes and the reference voltage generation unit;
a sensing voltage generation unit that applies a voltage for defining a predetermined voltage difference with respect to the reference voltage to the disconnection detection unit;
and
a disconnection determination unit connected to a first node at which a magnitude of a voltage signal applied by the voltage dividing resistor varies according to whether at least one of the transformation unit and a circuit connected to the transformation unit is disconnected, among the plurality of nodes, and configured to detect whether at least one of the transformation unit and a circuit connected to the transformation unit is disconnected from a voltage signal detected from the first node.

1 more element

A method of detecting a disconnection for a protective relay that detects whether a transformation unit and a circuit connected to the transformation unit are disconnected, the method comprising:

providing a plurality of nodes connected to both output ends of the transformation unit, and providing a plurality of resistors constituting a voltage dividing resistor to detect a voltage signal from a disconnection detection unit in which voltage signals applied to the plurality of nodes vary according to whether at least one of the transformation unit and a circuit connected to the transformation unit is disconnected, and acquire a DC offset value from the detected voltage signal;
comparing the acquired DC offset value with a preset threshold voltage to primarily determine whether at least one of the transformation unit and a circuit connected to the transformation unit is disconnected;
calculating a magnitude of an AC component from the detected voltage signal according to the primary determination result;
comparing the calculated magnitude of the AC component with a preset AC current signal magnitude to determine whether a short-circuit current or an in-rush current of the transformation unit is generated;
and
secondarily determining whether at least one of the transformation unit and a circuit connected to the transformation unit is disconnected according to a result of determining whether the short-circuit current or the in-rush current is generated.

3 more elements

Dependencies are inferred from the claim text.

Protective relay and method for detecting disconnection of protective relay

Life of this patent

Protective relay and method for detecting disconnection of protective relay

Life of this patent

Abstract

Claims23