Protection apparatus and method of verifying operation thereof

Patent metadata

Field	Value
Publication number	US-9606169-B2
Application number	US-201414312355-A
Country	US
Kind code	B2
Filing date	Jun 23, 2014
Priority date	Jul 3, 2013
Publication date	Mar 28, 2017
Grant date	Mar 28, 2017

Abstract

A method of verifying a protection apparatus is provided. The method includes: setting a plurality of relay elements for sensing an abnormal state of the protection apparatus; receiving an input regarding test information for testing each of the plurality of relay elements; and when at least one of the plurality of relay elements is in an abnormal state from the reception of the input regarding the test information, identifying whether the protection apparatus has created an abnormal state sensing signal.

First claim

What is claimed is:

1. A method of verifying a protection apparatus, the method comprising:
applying a test current to an alternating current (AC) bus to identify a line connection state of an inner circuit of the protection apparatus, the AC bus configured to connect an input terminal of a double tune filter to an input terminal of a high pass filter and transmit AC power supplied from an AC power source to the double tune filter and the high pass filter;
identifying that there is no misconnection in the inner circuit when all the output currents of the double tuned filter and the high pass filter are zero with respect to the applied test current;
setting a plurality of relay elements for sensing an abnormal state of the protection apparatus when there is no misconnection;
receiving an input related to test information for testing each of the plurality of relay elements, the input related to test information including a micro current that is input to the double tuned filter;
comparing a level of the micro current input to the double tuned filter with a level of a current output from the double tuned filter; and
identifying that an abnormal state is generated when a difference between the micro current input to the double tuned filter and the level of the current output from the double tuned filter exceeds a preset value,
wherein the plurality of relay elements comprise an overcurrent relay element, a ground overcurrent relay element, an unbalanced current relay element and a percentage differential relay element.

2. The method according to claim 1 , further comprising identifying a point at which a misconnection exists in the inner circuit according to the identified line connection state.

3. The method according to claim 1 , wherein the plurality of relay elements further comprise a harmonic overcurrent relay element when the protection apparatus is protecting an AC filter.

4. The method according to claim 1 , wherein setting the plurality of relay elements comprises setting a minimum preset value necessary for generation of the abnormal state for each of the plurality of relay elements.

5. A protection apparatus applying a test current to identify a line connection state of an inner circuit of the protection apparatus, the protection apparatus comprising:
a double tuned filter;
a high pass filter;
an alternating current (AC) bus configured to connect an input terminal of the double tune filter to an input terminal of the high pass filter and transmit AC power supplied from an AC power source to the double tune filter and the high pass filter;
a filter protection unit configured to:
apply the test current to the AC bus to identify the line connection state,
identify that there is no misconnection when all the output currents of the double tuned filter and the high pass filter are zero with respect to the applied test current;
set a plurality of relay elements for sensing an abnormal state of the protection apparatus when there is no misconnection;
receive an input related to test information for testing each of the plurality of relay elements, the input regarding test information including a micro current that is input to the double tuned filter;
compare a level of the micro current input to the double tuned filter with a level of a current output from the double tuned filter,
identify that an abnormal state is generated when a difference between the micro current input to the double tuned filter and the level of the current output from the double tuned filter exceeds a preset value,
wherein the plurality of relay elements comprise an overcurrent relay element, a ground overcurrent relay element, an unbalanced current relay element and a percentage differential relay element.

6. The protection apparatus according to claim 5 , wherein the protection apparatus further identifies a point at which the misconnection exists in the inner circuit according to the identified line connection state.

7. The protection apparatus according to claim 5 , wherein the plurality of relay elements further comprise a harmonic overcurrent relay element when the protection apparatus is protecting the AC filter.

8. The protection apparatus according to claim 5 , wherein the protection apparatus further sets a minimal preset value necessary for generation of the abnormal state for each of the plurality of relay elements.

Assignees

• Lsis Co Ltd

Inventors

• Choi Ho Seok
• Choi Yong Kil

Classifications

• H02H7/125

  for rectifiers · CPC title

• H02H7/1213

  for DC-DC converters · CPC title

• G01R31/3271

  of high voltage or medium voltage devices (G01R31/333 takes precedence) · CPC title

• G01R31/2827 Primary

  Testing of electronic protection circuits (testing switches G01R31/327; checking alarm systems G08B29/00; self test of summation current transformers H02H3/335) · CPC title

• H02H3/044

  Checking correct functioning of protective arrangements, e.g. by simulating a fault (for differential current circuit breakers H02H3/335) · CPC title