Claims:
1. A system for pre-processing an input signal, said system comprising:
a signal conditioning module (3) configured to:
receive monitored currents for all three-phases of a three-phase system;
utilize a non-inverting operational amplifier (5) to process a first monitored current I1 of a first phase based on a first weight value;
utilize a first inverting amplifier (6) to process a second monitored current I2 of a second phase based on a second weight value;
utilize a second inverting amplifier (7) to process a third monitored current I3 of a third phase based on said second weight value; and
add the processed first, second, and third monitored currents using an adder (7a) to obtain summation output of first, second, and third monitored currents;
generate, using an attenuator, an output current signal I1’ for an end application (4) based on said third weight value.

2. The system as claimed in claim 1, wherein the first weight value is 1.

3. The system as claimed in claim 1, wherein the second weight value is -0.5.

4. The system as claimed in claim 1, wherein the third weight value is 1.5.

5. The system as claimed in claim 1, wherein the signal conditioning module (3) comprises:
an operational amplifier adapted to utilize a second monitored current I2 of a second phase and a third monitored current I3 of a third phase to add the processed second, and third monitored currents using an adder (10) to obtain a summation output of second and third monitored currents, and thereby a third inverting amplifier (11) utilizes the summation output of second and third monitored currents for processing based on a fourth weight value, the fourth weight value is -0.5.

6. The system as claimed in claim 1, further comprises: a sensor 1 configured to monitor current flowing through all three-phases of the three-phase system and transmit the monitored current to the signal conditioning module (3).

7. The system as claimed in claim 5, wherein the sensor (1) is selected from any or combination of a current transformer and a Rogowski sensor.

8. The system as claimed in claim 1, wherein the end application (4) comprises an electronic trip unit to determine issuance of a trip signal.

9. The system as claimed in claim 1, wherein the end application is a fault detection system.

10. The system as claimed in claim 1, wherein the monitored current is selected from any or combination of an analog signal and a digital signal.

11. A method for pre-processing an input signal, said method comprising the steps of:
receiving, at a signal conditioning module (3), monitored currents for all three-phases of a three-phase system,
utilizing, a non-inverting operational amplifier (5) of the signal conditioning module (3), to process a first monitored current I1 of a first phase based on a first weight value;
utilizing, a first inverting amplifier (6) of the signal conditioning module (3), to process a second monitored current I2 of a second phase based on a second weight value;
utilizing, a second inverting amplifier (7) of the signal conditioning module (3), to process a third monitored current I3 of a third phase based on said second weight value;
adding, using an adder of the signal conditioning module (3), the processed first, second, and third monitored currents to obtain summation output of first, second, and third monitored currents; and
generating, using an attenuator, an output current signal I1’ for an end application (4) based on said third weight value.
, Description:
TECHNICAL FIELD
[0001] The present disclosure relates to field of signal processing, and more specifically relates to a signal conditioning system and method for multi-phase system to eliminate noise from a sensor current in an electric network, as well as to an apparatus which uses this method.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] The invention will be illustrated with particular reference to a preferred application in a low-voltage electrical power distribution network, although this is not to be understood as limiting, and in any event the invention applies in general to high, medium and low-voltage networks.
[0004] Faults (short circuits) are inevitable. Any power system is expected to suffer several faults each year. The number will depend on exposure to lightning and damage from trees, as well as the age of the system's components. When a short circuit fault occurs in the distribution network, a short circuit current will flow to the fault location. This short circuit current is detected and cleared by existing protection equipment, such as circuit breakers or fuses. However, when fault levels go beyond the existing design limits due to the connection of electrical equipment, uprating the capability of existing protection equipment such as circuit breakers is the only option to increase the fault level capabilities of the network.
[0005] Such faults may be caused because of the aging, supply overvoltage, and other such natural or man-made causes the electrical circuit contact or collide, and a sudden increase in current. Since the electrical short circuit line current suddenly increases, which large instantaneous heat release, heat much more than when the line is working properly, not only make the part of the electrical wiring insulation burned, but also can cause severe melted parts of the electrical circuit, causing fire fuel combustion, so the short-circuit failure caused the problem has been adversely affected and damage to production and life. Early fault detection is a technique intended to short circuit fault detection in micro second range. Early fault detection leads to faster and more effective maintenance, avoiding serious damage in machines and increasing the reliability, security and fault tolerance in industrial scenarios.
[0006] In electronics, signal conditioning means manipulating an analog signal in such a way that it meets the requirements of the next stage for further processing. Most common use is in analog-to-digital converters. In control engineering applications, it is common to have a sensing stage (which consists of a sensor), a signal conditioning stage (where usually amplification of the signal is done) and a processing stage (normally carried out by an ADC and a micro-controller). Operational amplifiers (op-amps) are commonly employed to carry out the amplification of the signal in the signal conditioning stage. In some transducers this feature will come inherent for e.g. in Hall Effect sensors. The signal conditioning method is useful in applications, such as early fault detection in a typical 3ph/3ph-4 wire system, having a signal conditioning circuit capable of conditioning a sensor input signal and providing an output useful for further processing in order to achieve accurate and faster detection.
[0007] Efforts have been made in related art to address above stated problem by using nonlinear filtering. An example of such nonlinear filtering is recited in IEEE paper, entitled “Smoothing of discontinuous signals: the competitive approach”, which uses this method. The papers discloses the method for competitive smoothing approach in which smoothed signal is estimated at each time step. This conceptually simple approach to nonlinear filtering is justified by considering set of kalman filters one moving forward in time, the other one moving backward in time. However the conventional method gives smoothed signal but with maximum delay in further processing.
[0008] Whereas there is certainly nothing wrong with existing techniques or methods used for smoothing of discontinuous signal, nonetheless, there still exists a need to provide an efficient, effective, reliable, improved system, method, and apparatus that enables preserving jump discontinuities while attenuating noise. Further, there exists a need signal conditioning method and apparatus which assist without any delay in case of digital processing.
[0009] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
[00010] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term “about”. Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
[00011] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[00012] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[00013] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
OBJECTS OF THE INVENTION
[00014] An object of the present disclosure is to provide to a signal conditioning system and method and apparatus for three phase system.
[00015] Another object of the present disclosure is to provide a signal conditioning system and method for three phase system to eliminate noise from a sensor current in an electric network, as well as to apparatus which uses this method.
[00016] Another object of the present disclosure is to provide an instantaneous smoothed signal which minimizes the delay in further processing by using a signal conditioning system and method.
[00017] Another object of the present disclosure is to provide a signal conditioning system and method to eliminate the delay which is likely to be produced in case of other signal conditioning approaches like moving point average or filtering which therefore facilitates faster processing by the electronic trip unit and results in early detection of fault even with noisy signal at the input.
[00018] Another object of the present disclosure is to provide a signal conditioning method and apparatus to monitor current signal through transformers or others sensors, which gives typically a noisy signal.
[00019] Another object of the present disclosure is to provide a method and a device for measuring analog signals and compensating for measurement errors to produce pre-processed signal.

SUMMARY
[00020] The present disclosure relates to field of signal processing, and more specifically relates to a signal conditioning system and method for three phase system to eliminate noise from a sensor current in an electric network, as well as to apparatus which uses this method.
[00021] Embodiments of the present disclosure provide an efficient, effective, reliable, improved system and method, apparatus that uses same method for preserving jump discontinuities while attenuating noise. Further, the present invention according to the embodiments provides/gives instantaneous smoothed signal which minimizes the delay in further processing.
[00022] Accordingly, an aspect of the present disclosure relates to a system for pre-processing an input signal. The system can include a signal conditioning module, a non-inverting operational amplifier, a first inverting amplifier, a second inverting amplifier and an adder. In another aspect, the signal conditioning module can receive monitored currents for all three-phases of a three-phase system. In another aspect, the non-inverting operational amplifier can process a first monitored current I1 of a first phase based on a first weight value. In another aspect, the first inverting amplifier can process a second monitored current I2 of a second phase based on a second weight value. In another aspect, the second inverting amplifier can process a third monitored current I3 of a third phase based on said second weight value. In another aspect, an adder can add the processed first, second, and third monitored currents to obtain summation output of first, second, and third monitored currents. In an aspect, an attenuator generates an output current signal I1’ for an end application based on said third weight value.
[00023] In an aspect, the first weight value can be 1. In an aspect, the second weight value can be -0.5. In an aspect, the third weight value can be 1.5.
[00024] In an aspect, the signal conditioning module can include an operational amplifier adapted to utilize a second monitored current I2 of a second phase and a third monitored current I3 of a third phase to add the processed second, and third monitored currents using an adder (10) to obtain a summation output of second and third monitored currents, and thereby a third inverting amplifier (11) utilizes the summation output of second and third monitored currents for processing based on a fourth weight value, the fourth weight value is -0.5.
[00025] In an aspect, the system further can include a sensor to monitor current flowing through all three-phases of the three-phase system and transmit the monitored current to the signal conditioning module.
[00026] In an aspect, the sensor can be selected from any or combination of a current transformer and a Rogowski sensor.
[00027] In an aspect, the end application can include an electronic trip unit to determine issuance of a trip signal.
[00028] In an aspect, the end application can be a fault detection system
[00029] In an aspect, the monitored current can be selected from any or combination of an analog signal and a digital signal.
[00030] An aspect of the present disclosure relates to a method for pre-processing an input signal. The method includes the step of: receiving, at a signal conditioning module, monitored currents for all three-phases of a three-phase system; utilizing, a non-inverting operational amplifier of the signal conditioning module, to process a first monitored current I1 of a first phase based on a first weight value; utilizing, a first inverting amplifier of the signal conditioning module, to process a second monitored current I2 of a second phase based on a second weight value; utilizing, a second inverting amplifier of the signal conditioning module, to process a third monitored current I3 of a third phase based on said second weight value; adding, using an adder of the signal conditioning module, the processed first, second, and third monitored currents to obtain summation output of first, second, and third monitored currents; and generating, using an attenuator, an output current signal I1’ for an end application (4) based on said third weight value.
[00031] In contrast to the conventional signal conditioning method, the present disclosure illustrates the current conditioning concept associated with pre-processing a signal for a typical electronic trip unit in a 3-ph/ 3-ph 4 wire systems. Further, in contrast to the existing signal conditioning methods, the present invention provides an improved method that eliminates the delay which is likely to be produced in case of other signal conditioning approaches like moving point average or filtering which therefore facilitates faster processing by the electronic trip unit and results in early detection of fault even with noisy signal at the input. Unlike the conventional signal conditioning methods or filtering present invention gives instantaneous smoothed signal which minimizes the delay in further processing.
[00032] Further, in contrast to the existing signal conditioning methods or filtering methods, the present invention involves a signal conditioning module that facilitates accurate current measurement with improved signal to noise ratio which can then be send to the processing system (electronic trip unit in case of a fault detection device). The present invention is also capable of monitoring current signal through transformers or others sensors, which gives typically a noisy signal.
[00033] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[00034] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams are for illustration only, which thus is not a limitation of the present disclosure, and wherein:
[00035] FIG. 1 illustrates a block diagram representation of a 3-phase system with signal conditioning module for a particular application, in accordance with an exemplary embodiment of the present disclosure.
[00036] FIG. 2 illustrates an exemplary methodology for one phase current conditioning scheme according to an embodiment of this invention, in accordance with an exemplary embodiment of the present disclosure.
[00037] FIG. 3 illustrates an alternate topology of analog signal conditioning module, in accordance with an exemplary embodiment of the present disclosure.

DETAILED DESCRIPTION
[00038] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
[00039] If the specification states a component or feature “may”, “can”, “could”, or “might” be included or have a characteristic, that particular component or feature is not required to be included or have the characteristic.
[00040] As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[00041] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. These exemplary embodiments are provided only for illustrative purposes and so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. The invention disclosed may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Various modifications will be readily apparent to persons skilled in the art. The general principles defined herein may be applied to other embodiments and applications without departing from the scope of the invention. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure). Also, the terminology and phraseology used is for the purpose of describing exemplary embodiments and should not be considered limiting. Thus, the present invention is to be accorded the widest scope encompassing numerous alternatives, modifications and equivalents consistent with the principles and features disclosed. For purpose of clarity, details relating to technical material that is known in the technical fields related to the invention have not been described in detail so as not to unnecessarily obscure the present invention.
[00042] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.
[00043] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
[00044] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.
[00045] The present disclosure relates to field of signal processing, and more specifically relates to a signal conditioning system and method for three phase system to eliminate noise from a sensor current in an electric network, as well as to apparatus which uses this method.
[00046] Embodiments of the present disclosure provide an efficient, effective, reliable, improved system and method, apparatus that uses same method for preserving jump discontinuities while attenuating noise. Further, the present invention according to the embodiments provides/gives instantaneous smoothed signal which minimizes the delay in further processing.
[00047] Accordingly, an aspect of the present disclosure relates to a system for pre-processing an input signal. The system can include a signal conditioning module, a non-inverting operational amplifier, a first inverting amplifier, a second inverting amplifier and an adder. In another aspect, the signal conditioning module can receive monitored currents for all three-phases of a three-phase system. In another aspect, the non-inverting operational amplifier can process a first monitored current I1 of a first phase based on a first weight value. In another aspect, the first inverting amplifier can process a second monitored current I2 of a second phase based on a second weight value. In another aspect, the second inverting amplifier can process a third monitored current I3 of a third phase based on said second weight value. In another aspect, an adder can add the processed first, second, and third monitored currents to obtain summation output of first, second, and third monitored currents. In an aspect, an attenuator generates an output current signal I1’ for an end application based on said third weight value.
[00048] In an aspect, the first weight value can be 1. In an aspect, the second weight value can be -0.5. In an aspect, the third weight value can be 1.5.
[00049] In an aspect, the signal conditioning module can include an operational amplifier adapted to utilize a second monitored current I2 of a second phase and a third monitored current I3 of a third phase to add the processed second, and third monitored currents using an adder (10) to obtain a summation output of second and third monitored currents, and thereby a third inverting amplifier (11) utilizes the summation output of second and third monitored currents for processing based on a fourth weight value, the fourth weight value is -0.5. In an aspect, an attenuator generates an output current signal I1’ for an end application based on said third weight value.
[00050] In an aspect, the system further can include a sensor to monitor current flowing through all three-phases of the three-phase system and transmit the monitored current to the signal conditioning module.
[00051] In an aspect, the sensor can be selected from any or combination of a current transformer and a Rogowski sensor.
[00052] In an aspect, the end application can include an electronic trip unit to determine issuance of a trip signal.
[00053] In an aspect, the end application can be a fault detection system
[00054] In an aspect, the monitored current can be selected from any or combination of an analog signal and a digital signal.
[00055] An aspect of the present disclosure relates to a method for pre-processing an input signal. The method includes the step of: receiving, at a signal conditioning module, monitored currents for all three-phases of a three-phase system; utilizing, a non-inverting operational amplifier of the signal conditioning module, to process a first monitored current I1 of a first phase based on a first weight value; utilizing, a first inverting amplifier of the signal conditioning module, to process a second monitored current I2 of a second phase based on a second weight value; utilizing, a second inverting amplifier of the signal conditioning module, to process a third monitored current I3 of a third phase based on said second weight value; adding, using an adder of the signal conditioning module, the processed first, second, and third monitored currents to obtain summation output of first, second, and third monitored currents; and generating, using an attenuator, an output current signal I1’ for an end application (4) based on said third weight value.
[00056] In contrast to the conventional signal conditioning method, the present disclosure illustrates the current conditioning concept associated with pre-processing a signal for a typical electronic trip unit in a 3-ph/ 3-ph 4 wire systems. Further, in contrast to the existing signal conditioning methods, the present invention provides an improved method that eliminates the delay which is likely to be produced in case of other signal conditioning approaches like moving point average or filtering which therefore facilitates faster processing by the electronic trip unit and results in early detection of fault even with noisy signal at the input. Unlike the conventional signal conditioning methods or filtering present invention gives instantaneous smoothed signal which minimizes the delay in further processing.
[00057] Further, in contrast to the existing signal conditioning methods or filtering methods, the present invention involves a signal conditioning module that facilitates accurate current measurement with improved signal to noise ratio which can then be send to the processing system (electronic trip unit in case of a fault detection device). The present invention is also capable of monitoring current signal through transformers or others sensors, which gives typically a noisy signal.
[00058] FIG. 1 illustrates a block diagram representation of a 3-phase system with signal conditioning module for a particular application, in accordance with an exemplary embodiment of the present disclosure.
[00059] In an embodiment, a 3 phase system with a signal conditioning module 3 is illustrated in FIG. 1. The source and load can be connected via power line through a circuit breaker. Current sensors 1 for phases R, Y and B having a high bandwidth sense the load current flowing through the three phases. Sensed current signals can fed to the A/D converter 2 to get the discrete signal output and then passed to the signal conditioning module 4. In case of analog signal conditioning, requirement of A/D converter 2 can be avoided. The module 3 then produces an output optimum for the end application 5. A typical example for an end application 4 is fast fault detection in LV systems where output of the signal conditioning module 4 can be fed to the control unit for further processing. The control unit or electronic trip unit can be a microcontroller based system that contains peripherals like ADCs and timers. The fault detection algorithm can be executed by the microcontroller in real time and upon detection of short circuit fault the trip signal is issued to the circuit breaker. In another exemplary embodiment, the end application 4 can include an electronic trip unit to determine issuance of a trip signal.
[00060] In an exemplary embodiment, the present disclosure provides the current conditioning concept associated with pre-processing a signal for a typical electronic trip unit in a 3-ph/ 3-ph 4 wire systems. The method aims at estimating the accurate current signal in one phase(R) by utilizing signals in the other two phases. The method eliminates the delay which is likely to be produced in case of other signal conditioning approaches like moving point average or filtering which therefore facilitates faster processing by the electronic trip unit and results in early detection of fault even with noisy signal at the input. The present method for signal conditioning improves the signal to noise ratio thus has the application in sensitive fault detection techniques where presence of noise may lead to nuisance tripping or delayed fault detection.
[00061] It may be appreciated that, the present invention relates to a novel method for an analog/digital signal conditioning module in 3-ph/ 3-ph 4 wire system. In general, the intended method is allowed to monitor current signal through transformers or others sensors 1, which gives typically a noisy signal. The signal conditioning module 3 can enables accurate current measurement with improved signal to noise ratio which can then be send to the processing system 4 (electronic trip unit in case of a fault detection device).
[00062] In an embodiment, a system for pre-processing an input signal included of a sensor 1 that monitors the current, sensed current is then digitized by an Analog to digital converter 2 in case of digital signal processing. The proposed method allows analog/digital signals to be utilized by signal conditioning module 3. In order to estimate current in one phase say R, the other two phase currents are added (IY+ IB) using an adder circuit and negative of this value is assigned to (IR’’= -(IY+ IB)). The noise factor due to external environment get added as well which makes (IR’’= -(IY+ IB+2n)). To nullify the effect of noise, sensed current in R phase (IR) is added to 50% scaled estimated IR’’ which further scaled down to 150% to achieve the true value at a given instant of time. The method allows conditioning at every step. The signal thus received has reduced noise and also allows the conditioning at the same sample of current thereby eliminating any delay in processing.
[00063] In a typical balanced 3 phase 3 wire system: Sensed current in the R phase, IR Sensed current in the R phase, (IR+n ) (1)
Estimated current, (2)
Corrected Signal, (3)
[00064] In an exemplary embodiment, to perform such operation in analog system, current signal IR goes through a non-inverting operational amplifier having a constant gain (N) and gives the output IR, while the current signals in other two phases (IY, IB) are fed to an inverting operational amplifier having a steady gain (N). Output of Op-are further given to an adder followed by an attenuator to achieve the true value IR’. Addition is performed by Op-amp based adder network and a single quad Op-amp IC is capable of conditioning each phase current signal. Whereas signal conditioning with digitized data can be achieved by microcontroller based processing systems.
[00065] In an embodiment, a method and a device can be used for measuring analog signals and compensating for measurement errors to produce pre-processed signal. The power line runs from the source to the load. In an embodiment, the sensor 2 can monitor current flowing through all three-phases of the three-phase system and transmit the monitored current to the signal conditioning module 3. In another exemplary embodiment, the sensor can be selected from any or combination of a current transformer or a Rogowski sensor.
[00066] FIG. 2 illustrates an exemplary methodology for one phase current conditioning scheme according to an embodiment of this invention, in accordance with an exemplary embodiment of the present disclosure.
[00067] The block diagram of the methodology used for measurement of corrected one phase current is illustrated in FIG. 2. The output of the current sensor 2 can be directly fed to the signal conditioning module 3. Sensed current I1 can be passed through unity gain non-inverting operational amplifier 5 while the remaining two phase currents I2 and I3 are multiplied with weighing factor -0.5 by passing through inverting amplifiers 6 and 7. Further an adder block 8 can be used to calculate the summation of all three signals and further passed through an attenuator to estimate the corrected signal IR’. In order to obtain corrected current in 2nd phase, I2 signal is given to the non-inverting amplifier while other two phases are multiplied by negative weighing factor.
[00068] FIG. 3 illustrates an alternate topology of analog signal conditioning module, in accordance with an exemplary embodiment of the present disclosure. In an exemplary embodiment, the alternate topology of analog signal conditioning module is illustrated in FIG. 3. Sensed current I1 can be given to non-inverting amplifier while other two phase currents I2 and I3 are given to adder operational amplifier before feeding to inverting amplifier.
[00069] The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.
[00070] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced. Where the specification claims refers to at least one of something selected from the group consisting of A, B, C ….and N, the text should be interpreted as requiring only one element from the group, not A plus N, or B plus N, etc. The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the scope of the appended claims.
[00071] While embodiments of the present disclosure have been illustrated and described, it will be clear that the disclosure is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions, and equivalents will be apparent to those skilled in the art, without departing from the scope of the disclosure, as described in the claims.
[00072] In the description of the present specification, reference to the term "one embodiment," "an embodiments", "an example", "an instance", or "some examples" and the description is meant in connection with the embodiment or example described The particular feature, structure, material, or characteristic included in the present invention, at least one embodiment or example. In the present specification, the term of the above schematic representation is not necessarily for the same embodiment or example. Furthermore, the particular features structures, materials, or characteristics described in any one or more embodiments or examples in proper manner. Moreover, those skilled in the art can be described in the specification of different embodiments or examples are joined and combinations thereof.
[00073] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
[00074] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
[00075] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
[00076] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[00077] The present disclosure provides a signal conditioning system and method and apparatus for three phase system.
[00078] The present disclosure provides a signal conditioning system and method for three phase system to eliminate noise from a sensor current in an electric network, as well as to apparatus which uses this method.
[00079] The present disclosure provides an instantaneous smoothed signal which minimizes the delay in further processing by using a signal conditioning system and method.
[00080] The present disclosure provides a signal conditioning system and method to eliminate the delay which is likely to be produced in case of other signal conditioning approaches like moving point average or filtering which therefore facilitates faster processing by the electronic trip unit and results in early detection of fault even with noisy signal at the input.
[00081] The present invention provides a signal conditioning method and apparatus to monitor current signal through transformers or others sensors, which gives typically a noisy signal.
[00082] The present disclosure provides a method and a device for measuring analog signals and compensating for measurement errors to produce pre-processed signal.
[00083] The present disclosure provides better and faster results than conventional moving average.
[00084] The present disclosure provides a system and method that enables continuous signal conditioning to provide instantaneous true value.