Claims:1. A method of calculating sequence component for use in electromechanical based relays, the method comprising steps of;
converting analog samples into digital samples using an analog to digital converter (ADC);
applying Fourier transformation on individual phase input digital samples to obtain real (Ra, Rb, and Rc) and imaginary parts (Ia, Ib, and Ic) for each phase (A, B, and C);
computing negative sequence component, positive sequence component, and zero sequence component based on the real and imaginary parts for each phase;
calculating RMS value and phase angle value for the sequence component based on the negative sequence component, the positive sequence component, and the zero sequence component;
configuring a digital to analog converter (DAC) to receive the RMS value; and
configuring output of the DAC to be used as value of the sequence component for the electromechanical based relays.

2. The method of claim 1, wherein the ADC converts analog samples into digital samples with required sampling rate.

3. The method of claim 1, wherein the analog/digital samples are current and voltage input signals that are applied to an anti-aliasing filter for filtering particular frequency band signal.

4. The method of claim 1, wherein method further comprises the step of addition and subtraction of real and imaginary part of Phase B and C input signals as SUB_R = Rb - Rc, ADD_R = Rb + Rc, ADD_I = Ib + Ic, and SUB_I = Ib - Ic.

5. The method of claim 4, wherein the method further comprises the steps of:
multiplication of subtraction output of real and imaginary parts of Phases B and C with a first factor as MUL_OF_SUB_R = First Factor * SUB_R and MUL_OF_SUB_I = First Factor * SUB_I; and
multiplication of addition output of real and imaginary parts of Phases B and C with a second factor as MUL_OF_ADD_R = Second Factor * ADD_R and MUL_OF_ADD_R = Second Factor * ADD_I.

6. The method of claim 5, wherein the negative sequence component is computed as
Real Part = (Ra – (MUL_OF_ADD_R - MUL_OF_SUB_I))/3
Imaginary Part = (Ia – (MUL_OF_ADD_I - MUL_OF_SUB_R))/3

7. The method of claim 5, wherein the positive sequence component is computed as
Real Part = (Ra – (MUL_OF_ADD_R + MUL_OF_SUB_I))/3
Imaginary Part = (Ia – (MUL_OF_ADD_I + MUL_OF_SUB_R))/3

8. The method of claim 5, wherein the zero sequence component is computed as
Real Part = (Ra + Rb + Rc)/3
Imaginary Part = (Ia + Ib + Ic)/3

9. The method of claim 5, wherein the first factor is 0.866025 and the second factor is 0.5.
, Description:TECHNICAL FIELD
[0001] The present disclosure generally relates to a method for calculating sequence components of current and voltage in a power system, more particularly it discloses a technique for providing sequence component based protection in electromechanical relay.

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] Electrical power system normally operates in a balanced three-phase sinusoidal operation. When a tree contacts a line, a lightning bolt strikes a conductor or two conductors swing into each other, which is called as a fault or a fault on the line. When this occurs, the system goes from a balanced condition to an unbalanced condition. In order to properly set the protective relays, it is necessary to calculate currents and voltages in the system under such unbalanced operating conditions.
[0004] Low-voltage secondary power distribution networks consist of interlaced loops or grids supplied by two or more sources of power so that the loss of any one source will not result in an interruption of power. Such networks provide the highest level of reliability possible with conventional power distribution and are normally used to supply high-density load areas such as a section of a city, a large building or an industrial site. Each source is a medium voltage feeder supplying the network and consisting of a switch, a transformer and a network protector. The network protector consists of a circuit breaker and a control relay. The control relay senses the transformer and network voltages and line currents, and executes algorithms to initiate breaker tripping or closing action. Trip determination is based on detecting reverse power flow, that is, power flow from the network to the primary feeder.
[0005] Traditionally, network protector relays were electromechanical devices which tripped the circuit breaker open upon detection of power flow in the reverse direction. Such relays were provided with a recloser which closed the circuit breaker following a trip when conditions were favorable for forward current flow upon reclosing of the breaker. The electromechanical network protector relays are being replaced. One type of electronic network protector relay mimics the action of the electro-mechanical relay by calculating power flow. Another type of electronic network protector relay uses sequence voltages and currents to determine direction of current flow for making tripping decisions. Sequence analysis upon which such relays are based generates three vector sets to represent a three-phase voltage or current: a positive sequence vector, a negative sequence vector, and a zero sequence vector.
[0006] Sequence component method reduces complexity in solving electrical quantities during power system disturbances. These sequence components are known as positive, negative, and zero-sequence components. Conventional methods require following steps for calculating sequence component:
i. Analog to digital converter (ADC) converts analog signal into digital samples with required sampling rate.
ii. A microprocessor requires for extracting sequence components from desired samples (output of ADC).
iii. Apply Fourier transformation on current input signal (samples values).
iv. Calculate angle of respective phase.
v. Apply phase shift on individual phase.
vi. Use trigonometric method for calculating positive, negative and zero component.
vii. A scaled analog output has to generate with respect of calculated amplitude.
viii. This analog output will be work as input magnitude of sequence component for electromechanical relay.
[0007] In electromechanical relay, it is very difficult to calculate sequence component value in a normal way from accuracy point of view.
[0008] There is therefore a need in the art to provide a method for calculating amplitude of current and voltage, positive, negative and zero sequence components for electromechanical types of relay where high accuracy is desired.
[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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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 Markush groups used in the appended claims.

OBJECTS OF THE INVENTION
[0014] An object of the present disclosure is to provide a sequence component method to reduce complexity in solving electrical quantities.
[0015] Another object of the present disclosure is to provide a method to calculate sequence component in case of power system disturbances.
[0016] An object of the present disclosure is to provide a method for calculating amplitude of positive, negative, zero sequence of current/ voltage for electromechanical relay.
[0017] Another object of the present disclosure is to provide a method to calculate RMS and angle value of particular sequence component.
[0018] Yet another object of the present disclosure is to provide a method for calculating sequence components for electromechanical relay where high accuracy is desired.

SUMMARY
[0019] The present disclosure generally relates to a method for calculating sequence components of current and voltage in a power system, and more particularly, discloses a technique for providing sequence component based protection in electromechanical relay.
[0020] In an aspect, the present disclosure relates to a method of calculating sequence component for use in electromechanical based relays, the method comprising steps of converting analog samples into digital samples using an analog to digital converter (ADC); applying Fourier transformation on individual phase input digital samples to obtain real (Ra, Rb, and Rc) and imaginary parts (Ia, Ib, and Ic) for each phase (A, B, and C);computing negative sequence component, positive sequence component, and zero sequence component based on the real and imaginary parts for each phase; calculating RMS value and phase angle value for the sequence component based on the negative sequence component, the positive sequence component, and the zero sequence component; configuring a digital to analog converter (DAC) to receive the RMS value; and configuring output of the DAC to be used as value of the sequence component for the electromechanical based relays.
[0021] In an aspect, the ADC converts analog samples into digital samples with required sampling rate. In another aspect, analog/digital samples are current and voltage input signals that are applied to an anti-aliasing filter for filtering particular frequency band signal.
[0022] In yet another aspect, the proposed method can further include the step of addition and subtraction of real and imaginary part of Phase B and C input signals as SUB_R = Rb - Rc, ADD_R = Rb + Rc, ADD_I = Ib + Ic, and SUB_I = Ib - Ic. The method can further include the steps of multiplication of subtraction output of real and imaginary parts of Phases B and C with a first factor as MUL_OF_SUB_R = First Factor * SUB_R and MUL_OF_SUB_I = First Factor * SUB_I; and multiplication of addition output of real and imaginary parts of Phases B and C with a second factor as MUL_OF_ADD_R = Second Factor * ADD_R and MUL_OF_ADD_R = Second Factor * ADD_I. In an exemplary aspect, the first factor can be 0.866025 and the second factor can be 0.5.
[0023] In an aspect, the negative sequence component can be computed as
Real Part = (Ra – (MUL_OF_ADD_R - MUL_OF_SUB_I))/3
Imaginary Part = (Ia – (MUL_OF_ADD_I - MUL_OF_SUB_R))/3
[0024] In another aspect, the positive sequence component can be computed as
Real Part = (Ra – (MUL_OF_ADD_R + MUL_OF_SUB_I))/3
Imaginary Part = (Ia – (MUL_OF_ADD_I + MUL_OF_SUB_R))/3
[0025] In another aspect, the zero sequence component can be computed as
Real Part = (Ra + Rb + Rc)/3
Imaginary Part = (Ia + Ib + Ic)/3
[0026] In another aspect, the proposed disclosure discloses a method for calculating positive sequence, negative sequence, and zero sequence components of current and voltage in a power system, wherein the method can include computation of complex component of positive sequence component, negative sequence component, and zero sequence component. The method can further include computation of angle of positive sequence component, negative sequence component, and zero sequence component. The method can further include computation of amplitude of positive sequence component, negative sequence component, and zero sequence component, based on analog output for operating electromechanical relay can be computed.
[0027] 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
[0028] 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.
[0029] FIG.1 illustrates an exemplary block diagram of an electrical network in accordance to an embodiment of the present disclosure.
[0030] FIG.2 illustrates an exemplary block diagram of the proposed method for calculating sequence component in accordance to an embodiment of the present disclosure.
[0031] FIG.3 illustrates an exemplary block diagram of negative sequence component for the proposed method in accordance to an embodiment of the present disclosure.
[0032] FIG.4 illustrates an exemplary block diagram of positive sequence component for the proposed method in accordance to an embodiment of the present disclosure.
[0033] FIG.5 illustrates an exemplary block diagram of zero sequence component for the proposed method in accordance to an embodiment of the present disclosure.
[0034] FIG.6 illustrates an exemplary block diagram for RMS and angle calculation step of the proposed method in accordance to an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0035] 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 spirit and scope of the present disclosure as defined by the appended claims.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] The present disclosure generally relates to a method for calculating sequence components of current and voltage in a power system, more particularly it discloses a method of calculating positive sequence, negative sequence, zero sequence components for electromechanical types of relay.
[0041] In an aspect, the present disclosure relates to a method of calculating sequence component for use in electromechanical based relays, the method comprising steps of converting analog samples into digital samples using an analog to digital converter (ADC);applying Fourier transformation on individual phase input digital samples to obtain real (Ra, Rb, and Rc) and imaginary parts (Ia, Ib, and Ic) for each phase (A, B, and C);computing negative sequence component, positive sequence component, and zero sequence component based on the real and imaginary parts for each phase; calculating RMS value and phase angle value for the sequence component based on the negative sequence component, the positive sequence component, and the zero sequence component; configuring a digital to analog converter (DAC) to receive the RMS value; and configuring output of the DAC to be used as value of the sequence component for the electromechanical based relays.
[0042] In an aspect, the ADC converts analog samples into digital samples with required sampling rate. In another aspect, analog/digital samples are current and voltage input signals that are applied to an anti-aliasing filter for filtering particular frequency band signal.
[0043] In yet another aspect, the proposed method can further include the step of addition and subtraction of real and imaginary part of Phase B and C input signals as SUB_R = Rb - Rc, ADD_R = Rb + Rc, ADD_I = Ib + Ic, and SUB_I = Ib - Ic. The method can further include the steps of multiplication of subtraction output of real and imaginary parts of Phases B and C with a first factor as MUL_OF_SUB_R = First Factor * SUB_R and MUL_OF_SUB_I = First Factor * SUB_I; and multiplication of addition output of real and imaginary parts of Phases B and C with a second factor as MUL_OF_ADD_R = Second Factor * ADD_R and MUL_OF_ADD_R = Second Factor * ADD_I. In an exemplary aspect, the first factor can be 0.866025 and the second factor can be 0.5.
[0044] In an aspect, the negative sequence component can be computed as
Real Part = (Ra – (MUL_OF_ADD_R - MUL_OF_SUB_I))/3
Imaginary Part = (Ia – (MUL_OF_ADD_I - MUL_OF_SUB_R))/3
[0045] In another aspect, the positive sequence component can be computed as
Real Part = (Ra – (MUL_OF_ADD_R + MUL_OF_SUB_I))/3
Imaginary Part = (Ia – (MUL_OF_ADD_I + MUL_OF_SUB_R))/3
[0046] In another aspect, the zero sequence component can be computed as
Real Part = (Ra + Rb + Rc)/3
Imaginary Part = (Ia + Ib + Ic)/3
[0047] In an exemplary aspect, the present disclosure works on the following steps, which will be explained further in greater details to explain the proposed method with the help of figures and equations connecting the variables involved in the general working of the power system:

i. Analog to digital converter (ADC) converts analog signal into digital samples with required sampling rate.
ii. A microprocessor extracts sequence components from desired samples (output of ADC).
iii. Fourier transformation is applied for calculating complex components of individual phase input sample values.
iv. Complex components include real and imaginary rectangular coordinates.
v. Rectangular coordinates of sequence components using steps (shown in FIG. 2) are calculated.
vi. Using rectangular coordinates, RMS and Angle value of particular sequence component are calculated.
vii. RMS value feeds to the digital to analog converter are computed.
viii. Output of digital to analog converter is utilized as value of sequence component for electromechanical types of relay.
[0048] In another aspect, the proposed disclosure discloses a method for calculating positive sequence, negative sequence, and zero sequence components of current and voltage in a power system, wherein the method can include computation of complex component of positive sequence component, negative sequence component, and zero sequence component. The method can further include computation of angle of positive sequence component, negative sequence component, and zero sequence component. The method can further include computation of amplitude of positive sequence component, negative sequence component, and zero sequence component, based on analog output for operating electromechanical relay can be computed.
[0049] Referring to FIG. 1, view 100 shows four conductors namely a, b, c and neutral n between Network A 102 and Network B 104. The value of current and voltage for the conductors are as shown below:
Ia : Current in Phase A
Ib: Current in Phase B
Ic: Current in Phase C
In: Current in Neutral (n)
Van: Phase to neutral Voltage A
Vbn: Phase to neutral Voltage B
Vcn: Phase to neutral Voltage C
, wherein Ia, Ib, Ic are three input AC signal in FIG. 1. These input signals are considered as Phase A, Phase B, and Phase C inputs (shown in FIG. 2).
[0050] Referring to FIG. 2, view 200 shows ADC 202 to feed digital samples to microprocessor 204, which performs a Fourier transformation on three phase inputs from the ADC 202 followed by sequence component calculation 216. In the microprocessor 204, suitable operations from Adder 210, Adder 212 and then multiplier Factor A, or Subtractor 208, Subtractor 214 and then multiplier Factor B, take place as per the phase. Digital to Analog converter 218 works on the RMS value from Sequence component calculation 216 and the analog output is used by the electromagnetic relay.
[0051] Referring to FIG.3, view 300 shows steps in calculation of Real and Imaginary part of negative sequence component (Nr) as explained below. For Real Part, Subtractor 302 executes the operation (MUL_OF_ADD_R - MUL_OF_SUB_I) followed by subtraction of this value from Ra at Subtractor 304. Finally, Divider 306 divides the total value from Subtractor 304 as per the formula below.
Real Part = (Ra – (MUL_OF_ADD_R - MUL_OF_SUB_I))/3
For the Imaginary Part, Adder 308 executes the operation (MUL_OF_ADD_I + MUL_OF_SUB_R) followed by subtraction of this value from Ia at Subtractor 310. Finally, Divider 312 divides the total value from Subtractor 310 as per the formula below.
Imaginary Part = (Ia – (MUL_OF_ADD_I + MUL_OF_SUB_R))/3
[0052] Referring to FIG.4, view 400 shows the steps in calculation of Real and Imaginary part of positive sequence component (Pr) as explained below with the help of formulas.
For the Real Part, Adder 402 executes the operation (MUL_OF_ADD_R + MUL_OF_SUB_I) followed by subtraction of this value from Ra at Subtractor 404. Finally, Divider 406 divides the total value from Subtractor 404 as per the formula below.
Real Part = (Ra – (MUL_OF_ADD_R + MUL_OF_SUB_I))/3
For the Imaginary Part, Subtractor 408 executes the operation (MUL_OF_ADD_I - MUL_OF_SUB_R) followed by subtraction of this value from Ia at Subtractor 410. Finally, Divider 412 divides the total value from Subtractor 410 as per the formula below.
Imaginary Part = (Ia – (MUL_OF_ADD_I - MUL_OF_SUB_R))/3
[0053] Referring to FIG.5, view 500 shows steps in calculation of Real and Imaginary part of zero sequence component (Zr) as explained below with the help of formulas:
For the Real Part, Adder 502 executes the operation (Rb+Rc) followed by addition of this value to Ra at Subtractor 504. Finally, Divider 506 divides the total value from Subtractor 504 as per the formula below.
Real Part = (Ra + Rb + Rc)/3
For the Imaginary Part, Adder 508 executes the operation (Ib+Ic) followed by addition of this value to Ia at Subtractor 510. Finally, Divider 512 divides the total value from Subtractor 510 as per the formula below.
Imaginary Part = (Ia + Ib + Ic)/3
[0054] Referring to FIG.6, view 600shows steps in calculating RMS and output angle values. While calculating RMS value, adder 602 receives values of square of real and imaginary parts. Square root 604 takes the square root of the final value from Adder 602 to give the RMS value. While calculating output angle, Divider 606 performs the operation (Imaginary part/ Real part) which is fed to Tan-1 608, for calculating the output angle value after the (inverse tangent) operation.
[0055] In an aspect, sequence component can be calculated in following steps:
[0056] Step-1: Voltage and current input signal is applied to the Anti-Aliasing filter for filtering particular frequency band signal.
[0057] Step -2: ADC is required for converting analog instantaneous samples into digital quantities.
[0058] Step-3: Apply Fourier transformation on individual inputs of Phase-A, Phase-B, Phase-C, equation(1), equation(2), equation(3) respectively using any conventional method. Output of FFT would be Real part and imaginary part (shown in FIG. 2)
Ia: Imaginary part of Fourier transformation of Phase A
Ra: Real part of Fourier transformation of Phase A
Ib: Imaginary part of Fourier transformation of Phase B
Rb: Real part of Fourier transformation of Phase B
Ic: Imaginary part of Fourier transformation of Phase C
Rc: Real part of Fourier transformation of Phase C
[0059] Step-4: Calculate Addition and subtraction of real and imaginary part of Phase B and Phase C input signals.
SUB_R = Rb – Rc
ADD_R = Rb + Rc
ADD_I = Ib + Ic
SUB_I= Ib-Ic
[0060] Step -5: To calculate following parameters, values of multiplying factors, Factor A and Factor B are 0.5 and 0.866025 respectively.
MUL_OF_SUB_R = Factor B * SUB_R
MUL_OF_ADD_R = Factor A * ADD_R
MUL_OF_SUB_I = Factor B * SUB_I
MUL_OF_ADD_I = Factor A * ADD_I
[0061] Step-6: For negative sequence component (sown in FIG. 3):
Real Part = (Ra – (MUL_OF_ADD_R - MUL_OF_SUB_I))/3
Imaginary Part = (Ia – (MUL_OF_ADD_I + MUL_OF_SUB_R))/3
[0062] Step-7: For Positive sequence component (shown in FIG. 4):
Real Part = (Ra – (MUL_OF_ADD_R + MUL_OF_SUB_I))/3
Imaginary Part = (Ia – (MUL_OF_ADD_I - MUL_OF_SUB_R))/3

[0063] Step-8: For zero sequence components (shown in FIG. 5):
Real Part = (Ra + Rb + Rc)/3
Imaginary Part = (Ia + Ib + Ic)/3
[0064] Step-9: Calculate RMS value and phase angle using conventional method (shown inFIG. 6)
[0065] Step-10: Calculated magnitude should be scale down with fix value and fed to digital to analog converter.
[0066] Step-11: Output of digital to analog converter will be input of electromechanical relay. Electromechanical relay can use this input for providing protection on behalf on sequence component.
[0067] 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.
[0068] 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.
[0069] 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.
[0070] 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.
[0071] 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.
[0072] 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.

ADVANTAGES OF THE INVENTION
[0073] The present disclosure provides a method that increases accuracy for calculating sequence components for electromechanical relays.
[0074] The present disclosure provides a method that finds application in case of unbalanced operations in power systems.
[0075] The present disclosure provides a method that further reduces complexity in solving for electrical quantities during power system disturbances.
[0076] The present disclosure provides a method which enhances simplicity and accuracy of calculating symmetrical components from phase quantities.