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Digital protection relay and operation method thereof

A protection relay, digital technology, applied in emergency protection circuit devices, emergency protection devices with automatic disconnection, electrical components, etc., can solve problems such as relay component malfunction, frequency measurement noise influence, etc.

Inactive Publication Date: 2015-04-29
LSIS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, frequency measurements using this zero-crossing scheme may have a structure that is susceptible to noise included in the input voltage signal
Especially, if external noise is introduced so that the input signal deviates from the zero-crossing point, a large error will be generated between the measured frequency and the actual frequency, thereby causing malfunction of the frequency change rate relay element (81R)

Method used

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  • Digital protection relay and operation method thereof
  • Digital protection relay and operation method thereof
  • Digital protection relay and operation method thereof

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Embodiment Construction

[0022] Hereinafter, a digital protective relay and an operating method of the digital protective relay according to the present disclosure will be described in detail with reference to the accompanying drawings.

[0023] figure 1 is a flowchart illustrating the operation of a frequency change rate relay element of a digital protective relay according to the prior art. First, a voltage signal input to system power is A / D converted and provided as an input signal ( S10 ). Next, the timing at which the zero point crosses is detected from the waveform of the supplied input signal ( S20 ). The process of detecting the timing of a zero-crossing based on frequency measurements in this way is called a zero-crossing scheme. refer to figure 2 , the graph shows sampling data of a voltage signal input to the system power, and points of time crossing a zero point in the illustrated signal waveform are shown as arrows. If there is no intersection point in step S20, the process returns ...

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Abstract

The present disclosure relates to a digital protection relay and an operation method of the digital protection relay for enhancing the operation of a frequency change rate relay element (81R) thereof, and the digital protection relay and an operation method thereof may calculate a plurality of different frequency change rates from the measured frequency and use a value of the frequency change rate selected based on a predetermined criteria in the control of a relay operation, thereby providing an effect of enhancing reliability for the operation of the frequency change rate relay element.

Description

[0001] Cross References to Related Applications [0002] Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and priority of Korean Provisional Application No. 10-2011-0061950 filed June 24, 2011, the entire contents of which Incorporated herein by reference. technical field [0003] The present disclosure relates to a protective relay and an operating method of the protective relay, and more particularly, to a protective relay for enhancing relay operation of a rate-of-frequency change relay element and an operating method of the protective relay. Background technique [0004] Generally, various protective relays can be used to protect feeders, motors, transformers, etc. in the power system. Such protective relays can be classified into mechanical and digital. Digital protective relays can include integrated functions of relays, communications, digital input / output contacts, etc. When a fault occurs at any point in the power system, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02H7/00
CPCH02H3/46
Inventor 郑锺振
Owner LSIS CO LTD