DESC:TECHNICAL FIELD
[0001] The present disclosure generally relates to projection relay, particularly to a system and method for breakage detection of CBCT in sensitive earth fault relay. More particularly, the present disclosure discloses sensitive earth fault detection and monitoring of CBCT.

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] A protection relay, also referred to as an Intelligent Electronic Device (IED), is a microcontroller based intelligent electronic device with a basic function to protect electrical equipment by tripping a circuit breaker and interrupting a power line, in case of over current or earth fault situations. The tripping signal on behalf of a trip coil or other actuator of the circuit breaker is generated by the protection relay, when the measured current in the line exceeds a nominal or preset value for a predefined time period.
[0004] Sensitive earth fault is provided in most of the protection relays, and core balanced current transformer (CBCT) is used for sensing the earth current. CBCT performs vector addition of all the phases and neutral passed though it and accordingly generates a signal that is equivalent to current signal passing through earth.
[0005] Monitoring the presence of CBCT is equally important in the protection relays along with the detection of earth fault. If a fault has occurred and CBCT is not connected to the protection relay, following issues may occur:
i. Relay may not trip the protection relay, as it will sense “Zero” earth fault current due to absence of CBCT input, even if the fault current is greater than set fault current.
ii. As burden to CBCT is normally present inside the relays, and if CBCT gets disconnected from the relay and current has passed through the system, high amount voltage will develop on CBCT output terminal as CT will consider infinite burden, and this high voltage can damage the CBCT.
[0006] To avoid issues mentioned above, monitoring of CBCT connection should be performed. User should be informed in case of disconnection of CBCT from earth fault/protection relay, and if required, hold/ trip the system in absence of CBCT when earth fault protection is activated.
[0007] Therefore, there is a need in the art to provide a system and method for breakage detection of CBCT by sensitive earth fault detection and sensor connections monitoring.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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
[0013] A general object of the present disclosure is to provide breakage detection of CBCT in sensitive earth fault relay.
[0014] Another object of the present disclosure is to provide a system and method for sensing presence of CBCT.
[0015] An object of the present disclosure is to provide a method that can restrict a circuit breaker to turn on a load, if absence of CBCT is detected.
[0016] Yet another object of the present disclosure is to provide runtime monitoring of CBCT connection.

SUMMARY
[0017] Aspects of the present disclosure pertain to sensitive earth fault detection and sensor connection monitoring for breakage detection of CBCT with internal burden resistor using BJT.
[0018] An embodiment of the present disclosure provides a system for monitoring presence of CBCT in a protection relay that incorporates a sensitive earth fault relay. The system includes a Bi-polar junction transistor (BJT), having its collector pin connected to a current controller resister (R1) that controls current passing through a supply to a burden resister (R2) of CBCT), a CBCT impedance (R3) equivalent to CBCT connected in parallel with the burden resister (R2) and a CPU configured to control the BJT to trigger a BJT output and check if the CBCT has been working or not. The CPU activates BJT output for a defined time interval (for example 1 mSec), if earth fault input has not been received for a predefined number of consecutive cycles, for example if the earth fault input has not been received for three consecutive cycles. The CPU read sensed voltage across the base resister (R2) for N samples taken at fixed interval (for example 100µSec), calculates average voltage for the N samples, compares calculated average voltage with a predefined voltage, and determines presence of the CBCT based on the calculated average voltage with a predefined voltage. Further, the CPU confirms presence of the CBCT if the average voltage lies within a tolerance range from the predefined voltage. The CPU can confirm absence of the CBCT, if the average voltage lies out of the tolerance range, say ±10%, of the predefined voltage.
[0019] In an exemplary implementation, base pin (B) of the BJT can be connected to a resister R5 and diode D1 that controls drive current required for the BJT and emitter pin (E) of the BJT can be connected to the base resister (R2).
[0020] In an exemplary implementation, the sensed voltage across the base register (R2) read by the CPU can be amplified by an OPAMP (U1A) and converted by an analogue to digital convertor (ADC) before feeding sensed voltage to the CPU.
[0021] In an exemplary implementation, the operational amplifier (OP-AMP) U1A can be used to amplify the input signal sensed across the burden resister R2. In an embodiment of the present disclosure, the burden resistor R2 can convert CBCT output current to a voltage signal that can further be amplified by an OP-AMP U1A, and the amplified output can be fed to ADC input of CPU. Burden resistor R2 and CBCT impedance R3 can be connected in parallel to each other such that in case CBCT is present, i.e. for any real value of R3, the resultant resistance of the present parallel connection and thereby average of N (such as 10) voltage samples can fall within the tolerance range of the set value (also referred interchangeably as predefined voltage). In a vice-versa case, when the average of N (such as 10) samples falls outside the tolerance range, conclusion can be made that the CBCT is missing.
[0022] More clarity can be achieved by taking the help of the equations mentioned below along with the general working principle:
If CBCT is present, Re = (R2*R3) / (R2+R3).
If CBCT is not present, Re = R2.
If a steady current “i” is passes through for detection of CBCT,
In presence of CBCT, V1 = i * {(R2*R3) / (R2+R3)}; and
In absence of CBCT, V2 = i *R2
When the above equations are compared, V2 > V1for any real value of R3.
[0023] In an aspect, the BJT output gets triggered, if no current has been detected on earth fault for M (such as 3) consecutive cycles, and ADC input voltage can be sensed to take N (such as 10) sample average and checks whether the average value lies within the tolerance range of set values. If the average value lies within the range, conclusion can be made that the CBCT has been connected, else in case of CBCT missing and there can be an error.
[0024] 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
[0025] 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.
[0026] FIG.1 illustrates an exemplary diagram of a CBCT presence detection system configured with an earth fault detection circuit in accordance to an embodiment of the present disclosure.
[0027] FIG.2 illustrates an exemplary diagram of an equivalent resistor for burden and CBCT impedance of the circuit in FIG. 1 in accordance to an embodiment of the present disclosure.
[0028] FIG.3 illustrates an exemplary flowchart for detecting CBCT breakage by the proposed method in accordance to an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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.
[0033] Various terms as used herein. To the extent a term used in a claim is not defined, 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.
[0034] Aspects of the present disclosure pertain to sensitive earth fault detection and sensor connection monitoring for breakage detection of CBCT with internal burden resistor using BJT.
[0035] An embodiment of the present disclosure provides a system for monitoring presence of CBCT in a protection relay that incorporates a sensitive earth fault relay. The system includes a Bi-polar junction transistor (BJT), having its collector pin connected to a current controller resister (R1) that controls current passing through a supply to a burden resister (R2) of CBCT), a CBCT impedance (R3) equivalent to CBCT connected in parallel with the burden resister (R2) and a CPU configured to control the BJT to trigger the BJT and check if the CBCT has been working or not. The CPU activate BJT output for a defined time interval (for example 1 mSec), if earth fault input has not been received for a predefined number of consecutive cycles, for example if the earth fault input has not been received for three consecutive cycles. The CPU read sensed voltage across the base resister (R2) for N samples taken at fixed interval (for example 100µSec), calculates average voltage for the N samples, compares calculated average voltage with a predefined voltage, and determines presence of the CBCT based on the calculated average voltage with a predefined voltage. Further, the CPU confirms presence of the CBCT if the average voltage lies within a tolerance range from the predefined voltage. The CPU can confirm absence of the CBCT, if the average voltage lies out of the tolerance range, say ±10%, of the predefined voltage.
[0036] In an exemplary implementation, base pin (B) of the BJT can be connected to a resister R5 and diode D1 that controls drive current required for the BJT and emitter pin (E) of the BJT can be connected to the base resister (R2).
[0037] In an exemplary implementation, the sensed voltage across the base register (R2) read by the CPU can be amplified by an OPAMP (U1A) and converted by an analogue to digital convertor (ADC) before feeding sensed voltage to the CPU.
[0038] In an exemplary implementation, the operational amplifier (OP-AMP) U1A can be used to amplify the input signal sensed across the burden resister R2. In an embodiment of the present disclosure, the burden resistor R2 can convert CBCT output current to a voltage signal that can further be amplified by an OP-AMP U1A, and the amplified output can be fed to ADC input of CPU. Burden resistor R2 and CBCT impedance R3 can be connected in parallel to each other such that in case CBCT is present, i.e. for any real value of R3, the resultant resistance of the present parallel connection and thereby average of N (such as 10) voltage samples can fall within the tolerance range of the set value (also referred interchangeably as predefined voltage). In a vice-versa case, when the average of N (such as 10) samples falls outside the tolerance range, conclusion can be made that the CBCT is missing.
[0039] More clarity can be achieved by taking the help of the equations mentioned below along with the general working principle:
If CBCT is present, Re = (R2*R3) / (R2+R3).
If CBCT is not present, Re = R2.
If a steady current “i” is passes through for detection of CBCT,
In presence of CBCT, V1 = i * {(R2*R3) / (R2+R3)}; and
In absence of CBCT, V2 = i *R2
When the above equations are compared, V2 > V1for any real value of R3.
[0040] In an aspect, the BJT output gets triggered, if no current has been detected on earth fault for M (such as 3) consecutive cycles, and ADC input voltage can be sensed to take N (such as 10) sample average and checks whether the average value lies within the tolerance range of set values. If the average value lies within the range, conclusion can be made that the CBCT has been connected, else in case of CBCT missing and there can be an error.
[0041] FIG. 1 shows an exemplary circuit 100 for CBCT presence detection system configured withearth fault detection in accordance with an embodiment of the present disclosure. Components present inside dotted circle of circuit enable detection of CBCT. The system includes a BJT (transistor Q1) having its collector pin connected to acurrent control resistor R1 configured to control current coming from a source, base pin connected toa resistor R5, diode D1, and emitter pin connected to burden resistor R2. In an exemplary implementation, burden resister can be connected in parallel with a CBCT impedance resistor (R3). In an exemplary implementation, the transistor Q1 can be driven by CPU to drive BJT output, whenever there is a need to detect CBCT presence. Current control resistor R1 manages/controls current coming from supply that can be intended for burden resistor R2. Resistor R5 and diode D1 is configured to control base current for base pin of the transistor Q1. Current output across the burden resistor R2 can be read and amplified by OP-AMP U1A. The amplified output received via voltage amplification by OP-AMP U1A can be fed to ADC input of CPU. In an embodiment of the present disclosure, transistor Q1 can be a BJT (Bipolar Junction Transistor) of BC 107A type.
[0042] In an embodiment of the present disclosure, current control resistor R1 limits the current (through supply) intended for the burden resistor R2.Transistor Q1acts like a switch that can be controlled by CPU. The resistor R5 anddiodeD1 can be configured to control drive current for base pin of the transistor Q1. Burden resistor R2 converts CBCT output current to voltage signal that can be amplified by OP-AMP U1A. Further the amplified output can be fed to ADC input of CPU. Burden resistor R2 and CBCT impedance R3 can be in parallel to each other such that in case CBCT is present i.e. for any real value of R3, the resultant resistance of the parallel connection (of R2 and R3) is read and thereby average of N (such as 10) voltage samples. Average of N voltage samples can be calculated and compared with a predefined threshold with a tolerance range. In average voltage of N samples are within a defined tolerance range of a set value, the CPU can conclude that CBCT is present and active. In vice-versa case, if the average of N samples falls outside the range, then CBCT can be determined as not connected to the relay.
[0043] In an embodiment, current control resistor R1 can be used to limit current passed though the supply into the burden resistor R2.Value for the current control resistor R1 can be selected as per current required to generate significant amount of voltage across burden when CBCT has been found absent. BJT Q1 can act like a switch that can be controlled by the CPU such that whenever CPU wants to detect presence of CBCT, it can drive the transistor Q1. The resistor R5 and diode D1 can be used for controlling drive current required for “Base” pin of Q1.Diode D2 is added to prevent supply voltage form reverse kick back from CBCT if it is present during the detection. Operational amplifier (OP-AMP) U1Acan be used to amplify input signal and the output of the amplifier can be fed to ADC input of CPU. Burden resistor R2can be used to convert CBCT output current to voltage such that using amplification; it can be measured through ADC.CBCT Impedance R3can be equivalent impedance of CBCT.
[0044] In order to better understand the working of the proposed system for CBCT breakage detection, stepwise operation of detection principle has been mentioned as follows. A person having ordinary skill in the art will appreciate this working principle when studied along with the disclosed drawings:
[0045] 1. If current input has not been present i.e. if no current has been detected on earth fault input for N (such as 3) consecutive cycles, BJT output can be triggered for a defined time interval (that can be approximately 1msec).
[0046] 2. ADC input voltage can be sensed on input pin for 1msec in interval of 100µSec to take N (such as 10) voltage samples.
[0047] 3. Average of these N samples can be taken to check if the average value falls within tolerance range of ±10% of set value or not.
[0048] 4. If the value lies within ±10% tolerance of set value then CBCT can be in connected state,
[0049] 5. If the value does not lies within the range (i.e. ±10% tolerance) of set Value, CBCT missing or error can be declared.
[0050] FIG. 2 shows view 200 with equivalent resistor for burden R2 and CBCT impedance R3 of the circuit in FIG. 1 in accordance to an embodiment of the present disclosure. These elements can be in parallel to each other, and therefore an equivalent element for them can be Re, with the value of Re = (R2*R3) / (R2+R3). In an aspect, CBCT can have some impedance and when burden resistor R2 gets connected, resultant impedance value can be lower as the burden resistor R2 and CBCT impedance has become parallel to each other. If two impedances have been parallel to each other, resultant impedance can be lower than both of the impedances as shown below with the help of equations.
If CBCT is present, Re = (R2*R3) / (R2+R3).
If CBT is not present, Re = R2.
If a steady current “i” is passes thought for detection of CBCT then
In presence of CBCT, V1 = i * {(R2*R3) / (R2+R3)}; and
In absence of CBCT, V2 = i *R2
When the above equations are compared, V2 > V1for any real value of R3.
[0051] In an embodiment of the present disclosure, in order to detect CBCT, voltage “V” can be monitored (sensed though ADC) and if found near to voltage “V1” with tolerance of ±10% for considering component tolerances, current “i” can be set using current control resistor R1 from supply voltage and injection of the current “i” can be controlled by transistor Q1.Continuous injection can be avoided to save power. If the current has been sensed through ADC channels, CBCT can be said to be present and hence CBCT detection can only be required when there has been no current flowing through CBCT input.
[0052] FIG. 3 shows flowchart 300 for detecting the CBCT breakage by the proposed method by sensing the flowing of earth current over a three cycle period. The method detects whether earth current has been flowing or not, as shown at step 302. Based on the response ‘Yes’ or ‘No’ from step 302,checkswhethera predefined number of cycles, for example three cycle period, has been over, as shown at step 304. In case no current has been flowing at step 302 on earth fault and 3 consecutive cycles, as shown at step 304 is over, the BJT can be triggered to inject current ‘i’, as shown at step 306, and ADC input voltage can be sensed to take average of N samples in step 308.Next step can be to check whether the average value of N samples calculated in step 308 lies within a tolerance range of set values, as shown at step 310.If the average value lies within the tolerance limit, a conclusion can be made that CBCT is connected otherwise CBCT can be declared as missing, as shown at step 312.
[0053] In an embodiment, a CPU can control BJT to trigger the BJT output for a defined time interval, if earth fault input is not received for a predefined number of consecutive cycles. CPU can read sensed voltage across the base resister (R2) for N samples taken at fixed interval. Calculates average voltage for the N samples. Further, compares calculated average voltage with a predefined voltage, and determines presence of the CBCT based on the calculated average voltage with a predefined voltage. CPU can confirm presence of the CBCT if the average voltage has been found within a tolerance range from the predefined voltage.
[0054] In another embodiment, CPU can confirm absence of the CBCT if the average voltage has been found within a tolerance range from the predefined voltage.
[0055] 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.
[0056] 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.
[0057] 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.
[0058] 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.
[0059] 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.
[0060] 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.
[0061] 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.

ADVANTAGES OF THE INVENTION
[0062] The present disclosure provides a system and method with low cost mechanism to identify CBCT presence.
[0063] The present disclosure provides a system and method that ensures safety of equipment and user.
[0064] The present disclosure provides a system and method that enables run time monitoring of CBCT connection.
[0065] The present disclosure provides a system and method that saves power by avoiding continuous injection of current.
,CLAIMS:1. A system for detecting presence of core balanced current transformer CBCT, the system comprising:
a Bi-polar junction transistor (BJT), wherein collector pin of the BJT is connected to a current controller resister (R1) that controls current to a burden resister (R2) of CBCT ;

an impedance (R3) equivalent to CBCT connected in parallel with the burden resister (R2); and

a CPU configured to

control the BJT to trigger a BJT output for a defined time interval, if earth fault input is not received for a predefined number of consecutive cycles,
Read sensed voltage across the base resister (R2) for N samples taken at fixed interval,
Calculate average voltage for the N samples,
Compare calculated average voltage with a predefined voltage, and
Determine presence of the CBCT based on the calculated average voltage with a predefined voltage.
2. The system of claim 1, wherein the CPU confirms presence of the CBCT if the average voltage is within a tolerance range from the predefined voltage.

3. The system of claim 1, wherein the CPU confirms absence of the CBCT, if the average voltage is out of the tolerance range of the predefined voltage.

4. The system of claim 1, wherein base pin (B) of the BJT is connected to a resister R5 and diode D1 that controls drive current required for the BJT and emitter pin (E) of the BJT is connected to the base resister (R2).

5. The system of claim 1, wherein the voltage across the base register (R2) read by the CPU is an amplified voltage, amplified by an OPAMP (U1A) and converted by an analogue to digital convertor (ADC) before feeding to the CPU.

6. The system of claim 1, wherein the predefined number of consecutive cycles is three.

7. The system of claim 1, wherein the defined time interval is 1 mSec and the fixed internal is 100µSec.

8. The system of claim 1, wherein the tolerate range is ±10% from the predefined voltage.