METHOD FOR DETECTING A DEFECTIVE AMPLIFIER IN AN ANALOG SIGNAL CONDITIONING DEVICE OF A SWITCH

• US 20150062766A1
• Filed: 07/22/2014
• Published: 03/05/2015
• Est. Priority Date: 08/29/2013
• Status: Active Grant

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: WIDMANN, Stefan
• Granted Patent: US 10,658,836 B2
• Time in Patent Office: Days
• US Class Current: 361/78
• CPC Class Codes: H02H 3/044 Checking correct functioning of protective arrangements, e.g. by simulating a fault for differential current circuit breakers H02H3/335
• CPC Class Codes: H02H 3/05 with means for increasing reliability, e.g. redundancy arrangements for logic circuits H03K19/003
• CPC Class Codes: H02H 3/08 responsive to excess current responsive to abnormal temperature caused by excess current H02H5/04
• CPC Class Codes: H02H 7/222 for switches

Abstract

A method is disclosed for detecting a defective amplifier. The device includes an electronic tripping unit which respectively carries out a check in order to determine whether the energy through the switch satisfies a condition and trips the switch if the condition has been satisfied; and an analog/digital converter respectively outputting the two differently amplified analog signals as digital values. In an embodiment of the method, a decision is made regarding which of the two digital values is used to check the condition. To detect defective amplifiers in the signal conditioning device of tripping units during ongoing operation, a check is carried out to determine whether at least one of the two digital values is in a predefined range; if so, whether the two digital values each belonging to the same time are in a predefined tolerance range. A fault is signaled if this is not the case.

Claims

1. A method for detecting a defective amplifier in an analog signal conditioning device of a switch including mechanically separable contact elements and a tripping unit which respectively carries out a check downstream of the analog signal conditioning device to determine whether electrical energy flowing via the contact elements satisfies a condition and trips a separation of the contact elements if the condition has been satisfied, the signal conditioning device including at least one sensor unit to respectively emit an electrical analog signal proportional to the electrical energy, and at least one downstream amplifier to amplify the analog signal, an analog/digital converter being connected downstream and the two differently amplified analog signals each being passable to the analog/digital converter and being outputtable as digital values, wherein a decision is made regarding which of the respective two digital values is used to check the condition, the method comprising:

carrying out a check to determine whether at least one of the two digital values is in a defined range;

determining, if it is determined that at least one of the two digital values is in the defined range, whether the two digital values, each belonging to a same time, are in a defined tolerance range; and

signaling a fault if it is not determined that the two digital values, each belonging to the same time, are in the defined tolerance range.

2. The method of claim 1, wherein the determining includes comparing the at least two digital values of the two differently amplified signals.

3. The method of claim 1, wherein the signaled fault indicates a hardware defect of the amplifier.