US3593124A — Method and device for detecting and localizing ph…

Claim 1

Independent Claim 529 words

In the method for detecting and localizing faults which occur in a section of a polyphase alternating current line having phases a, b and c, said line having known inductive and ohmic resistances and wherein the magnitudes of direct voltage u, current intensity i and derivative di/dt are measured for each phase, the steps for specifically determining faults between phases of: calculating the following compound magnitudes of voltage and current intensity respectively between each two phases uab, ubc, uca and iab, ibc, ica, calculating the following compound inductive voltage drops respectively between each two phases including all nonresistive magnitudes calculating the following compound resistive voltage drops respectively between each two phases r(ia-ib) , r(ib-ic) , r(ic-ia) comparing for each group of two phases the compound voltage with the addition of said compound inductive and resistive voltage drops to which is successively and respectively affected by multiplication coefficients (xab, yab, etc.) whereby said latter voltage drops have an equation having the form of a straight line for each group of two phases: (uab xab vab+yab wab, ubc ... etc.) recording data of said equations, repeating the foregoing steps at regular intervals of time different from a full number of periods of the alternating current whereby there is obtained for each group of two phases equations of successive straight intersecting lines which are all concurrent to a same point having in a plane the coordinates of which are determined by said multiplication coefficient, an ordinate which corresponds to the distance of the fault with respect to the length of said line section, and switching off said line section in the event that said ordinate reaches a predetermined value: and the steps for specifically determining faults between any one phase and earth of: separately adding the current of each phase and the derivatives thereof, recording the last result of said addition, comparing said additions respectively with the previously recorded one, switching off said line section in the event that said comparison shows a predetermined ratio whereby there is ascertained that a significant homopolar component occurs: and the further steps in the presence of a significant homopolar component of: calculating for each phase and from said direct magnitudes the: 1. homopolar resistive voltage drops (va rhih) 2. resultant voltage drops including resistive, inductive and homopolar voltage drops as defined in Ohm''s law from which said homopolar resistive voltage drop is eliminated, affecting by muLtiplication successively and respectively coefficients (xa, ya) to said homopolar resistive voltage drop and to said resultant voltage drop whereby an equation having the form of a straight line is obtained for each phase including the phase in fault recording data of said equations even though no fault occurs, repeating the foregoing steps at regular intervals of time different from a full number of periods of the alternating current for each phase thereby providing for the determination of successive equations of straight lines, and utilizing data recorded just before a significant homopolar component occurs and data obtained just after said homopolar component occurs to determine a point to which cross the straight lines defined by said equations, said point having an ordinate which corresponds to the distance of the fault.

Claim 2

Dependent Claim 529 words

In the method for detecting and localizing faults which occur in a section of a polyphase alternating current line having phases a, b and c, said line having known inductive and ohmic resistances and wherein the magnitudes of direct voltage u, current intensity i and derivative di/dt are measured for each phase, the steps for specifically determining faults between phases of: calculating the following compound magnitudes of voltage and current intensity respectively between each two phases uab, ubc, uca and iab, ibc, ica, calculating the following compound inductive voltage drops respectively between each two phases including all nonresistive magnitudes calculating the following compound resistive voltage drops respectively between each two phases r(ia-ib) , r(ib-ic) , r(ic-ia) comparing for each group of two phases the compound voltage with the addition of said compound inductive and resistive voltage drops to which is successively and respectively affected by multiplication coefficients (xab, yab, etc.) whereby said latter voltage drops have an equation having the form of a straight line for each group of two phases: (uab xab vab+yab wab, ubc ... etc.) recording data of said equations, repeating the foregoing steps at regular intervals of time different from a full number of periods of the alternating current whereby there is obtained for each group of two phases equations of successive straight intersecting lines which are all concurrent to a same point having in a plane the coordinates of which are determined by said multiplication coefficient, an ordinate which corresponds to the distance of the fault with respect to the length of said line section, and switching off said line section in the event that said ordinate reaches a predetermined value: and the steps for specifically determining faults between any one phase and earth of: separately adding the current of each phase and the derivatives thereof, recording the last result of said addition, comparing said additions respectively with the previously recorded one, switching off said line section in the event that said comparison shows a predetermined ratio whereby there is ascertained that a significant homopolar component occurs: and the further steps in the presence of a significant homopolar component of: calculating for each phase and from said direct magnitudes the: 1. homopolar resistive voltage drops (va rhih) 2. resultant voltage drops including resistive, inductive and homopolar voltage drops as defined in Ohm''s law from which said homopolar resistive voltage drop is eliminated, affecting by muLtiplication successively and respectively coefficients (xa, ya) to said homopolar resistive voltage drop and to said resultant voltage drop whereby an equation having the form of a straight line is obtained for each phase including the phase in fault recording data of said equations even though no fault occurs, repeating the foregoing steps at regular intervals of time different from a full number of periods of the alternating current for each phase thereby providing for the determination of successive equations of straight lines, and utilizing data recorded just before a significant homopolar component occurs and data obtained just after said homopolar component occurs to determine a point to which cross the straight lines defined by said equations, said point having an ordinate which corresponds to the distance of the fault.

Claim 3

Dependent Claim 156 words

resultant voltage drops including resistive, inductive and homopolar voltage drops as defined in Ohm''s law from which said homopolar resistive voltage drop is eliminated, affecting by muLtiplication successively and respectively coefficients (xa, ya) to said homopolar resistive voltage drop and to said resultant voltage drop whereby an equation having the form of a straight line is obtained for each phase including the phase in fault recording data of said equations even though no fault occurs, repeating the foregoing steps at regular intervals of time different from a full number of periods of the alternating current for each phase thereby providing for the determination of successive equations of straight lines, and utilizing data recorded just before a significant homopolar component occurs and data obtained just after said homopolar component occurs to determine a point to which cross the straight lines defined by said equations, said point having an ordinate which corresponds to the distance of the fault.

Claim 4

Dependent Claim 156 words

resultant voltage drops including resistive, inductive and homopolar voltage drops as defined in Ohm''s law from which said homopolar resistive voltage drop is eliminated, affecting by muLtiplication successively and respectively coefficients (xa, ya) to said homopolar resistive voltage drop and to said resultant voltage drop whereby an equation having the form of a straight line is obtained for each phase including the phase in fault recording data of said equations even though no fault occurs, repeating the foregoing steps at regular intervals of time different from a full number of periods of the alternating current for each phase thereby providing for the determination of successive equations of straight lines, and utilizing data recorded just before a significant homopolar component occurs and data obtained just after said homopolar component occurs to determine a point to which cross the straight lines defined by said equations, said point having an ordinate which corresponds to the distance of the fault.

Claim 5

Dependent Claim 141 words

Method according to claim 1 comprising the further steps of recording during at least one current period the value of the compound voltages found, substituting said compound voltage values retained in Ohm''s law equation with said values of resistive and inductive voltage drops at the instant of determining a fault between phases, drawing up at least one of the corresponding straight lines, repeating the same operations at the moment of the next measurement, so that to draw at least one new straight line, and determining the sign of the ordinate of the intersection point of said two straight lines, this sign being positive when the fault is downstream from the measuring point and negative when said fault is upstream from the measuring point whereby it is determined if the fault between phases occurs in the section of line to be protected.

Claim 6

Dependent Claim 148 words

Method according to claim 1 comprising the further steps of using said data relative to homopolar components in an equation corresponding to Ohm''s law but limited to said homopolar components (uh rhihlh dih/dt), of grouping on the one hand, the components of the resistive homopolar voltage drops affected with a first numerical coefficient and, on the other hand, the inductive homopolar voltage drops affected with a second numerical coefficient to form the equation of a straight line (uh xhvh+yhwh) with the corresponding voltage homopolar component repeating the same operations at the following interval of time so that said two straight lines concur at a fictitious image point whose ordinate appears positive when the fault is upstream from the measuring point and negative when said fault is downstream whereby it is determined if the fault between a phase and earth occurs in the section of line to be protected.

Claim 7

Dependent Claim 143 words

Method according to claim 1 comprising the further steps of memorizing at least the value of the data obtained during a measure under the normal conditions of the line, recording new data during a subsequent measure whereby is obtained the equation of two straight lines at two successive measuring intervals, computing the abscissa and ordinate of the point at which the two straight lines concur, said abscissa and ordinate occurring in the form of two ratios, calculating separately the respective numerators of two ratios, and recording from computation of said two numerators, for the successive measuring intervals position of successive points whereby two curves are determined, one of said curves corresponding to the numerator of the abscissa being a representation of the active power and said curve corresponding to the ordinate being a representation of the reactive power circulating in the line section.

Claim 8

Dependent Claim 101 words

Method as set forth in claim 1, comprising for the measure of said electric direct magnitudes the steps of: measuring for each phase voltages corresponding respectively to said voltage, current intensity and derivative thereof during a predetermined sample time smalLer than said interval of time separating two measures, repeating said measuring a full number of times per period of the AC whereby mean values for said direct magnitude are successively obtained, changing said mean values into pulses, computing said respective number of pulses during said sample time and coding subsequently the same whereby data are obtained and usable in a computer.

Claim 9

Dependent Claim 95 words

Method as set forth in claim 5 comprising the further steps of computing said pulses during an entire or full number of periods of said AC determining if said number is nil or not, and in case said number is not nil of computing the number of pulses thus obtained for a time corresponding to said sample time whereby is obtained a false-zero value, and algebraically subtracting the number of pulses corresponding to said false-zero value from the number of pulses corresponding to each one of said electric magnitudes whereby errors of measurement are eliminated.

Claim 10

Dependent Claim 269 words

Device for detecting and localizing faults on a section of lines transporting polyphase alternating current comprising, for each phase conductor, means for measuring voltage between this phase conductor and earth, means for measuring current intensity circulating in said phase conductor, and means measuring derivative of said current intensity, at least one switching member connected to each of said measuring means at the output thereof, recording elements selectively connected to said switching members whereby said voltage, current intensity and derivative thereof are recorded during closing of said switching members, a driving clock unit having constant operating cycle and producing at least one operative signal of constant duration or integrating time during said operating cycle, the duration thereof being different from a full number of cycles of said AC members operatively connected to said switching members and to said clock unit end operated simultaneously during said operating signal thus causing recording of said voltage, current intensity and derivative thereof during said operative signal, a computer connected to said recording elements, whereby said voltage, current intensity and derivative thereof taken during said integrating time are supplied to said computer causing treatment thereof according to Ohm''s law equations having terms affected by said computer with coefficients whereby said Ohm''s law equations have the form of straight lines successively rotated to an extent corresponding to said cycle of said clock unit, successive rotated straight lines being concurrent to a single point characteristic of the existence of a fault, and switching-off means for said phase conductors of said section of lines and operated by said computer in dependency with the position of said single point.

Claim 11

Dependent Claim 269 words

Device for detecting and localizing faults on a section of lines transporting polyphase alternating current comprising, for each phase conductor, means for measuring voltage between this phase conductor and earth, means for measuring current intensity circulating in said phase conductor, and means measuring derivative of said current intensity, at least one switching member connected to each of said measuring means at the output thereof, recording elements selectively connected to said switching members whereby said voltage, current intensity and derivative thereof are recorded during closing of said switching members, a driving clock unit having constant operating cycle and producing at least one operative signal of constant duration or integrating time during said operating cycle, the duration thereof being different from a full number of cycles of said AC members operatively connected to said switching members and to said clock unit end operated simultaneously during said operating signal thus causing recording of said voltage, current intensity and derivative thereof during said operative signal, a computer connected to said recording elements, whereby said voltage, current intensity and derivative thereof taken during said integrating time are supplied to said computer causing treatment thereof according to Ohm''s law equations having terms affected by said computer with coefficients whereby said Ohm''s law equations have the form of straight lines successively rotated to an extent corresponding to said cycle of said clock unit, successive rotated straight lines being concurrent to a single point characteristic of the existence of a fault, and switching-off means for said phase conductors of said section of lines and operated by said computer in dependency with the position of said single point.

Claim 12

Dependent Claim 55 words

Device according to claim 7, characterized in that it comprises at least two switching elements connected to each measuring member and at least one recording element belonging to each switching element, said clock unit successively closing said two switching elements during integrating times equal between them respectively separated by time intervals also equal between them.

Claim 13

Dependent Claim 217 words

Device according to claim 7 in which said means for measuring the voltage of each phase conductor are connected to their respective conductor by a voltage divider, said means for measuring said current intensity are connected to their respective phase conductor by a shunt and said means measuring the derivative of the current are connected to their phase conductor by a transformer without iron, said means being all constituted by voltage-to-frequency converters, so that pulses modulated accordingly to the value of said voltage, current intensity, and derivative thereof are produced, a frequency-multiplying device being connected to each of said voltage-to-frequency converters and said frequency multipliers being, moreover respectively connected to mixing members also connected to a single reference frequency generator applying to Said frequency-mixing members a reference frequency differing from the interval of frequencies coming from said frequency multipliers but close to the limits of said frequency interval, at least one counter being connected to each mixing member and said counters, forming said switching elements, being all connected by a control link to said clock unit determining the integrating intervals and the time separating these intervals, so that said counters are opened by said clock unit for counting the number of pulses coming from said mixing members during integrating intervals, said counters being connected to said computer.

Claim 14

Dependent Claim 119 words

Device according to claim 9 comprising further a second counter connected to each of said mixing members, a reference counter device for current periods circulating in the phase conductors and connected to all the second counters for controlling their opening and an interval counter connected, on the one hand, to said controlling clock unit, and on the other hand, to said reference generator, so that said second counters are open for counting the number of pulses of said mixing members during an equal time, both to an entire number of current periods circulating in the section of line and an entire number of each time interval containing an integrating interval, said second counters being also connected to said computer.

Claim 15

Dependent Claim 56 words

Device according to claim 10, supplementarily further comprising, interposed between said voltage-to-frequency converters and those of said frequency multipliers determining the current intensity circulating in each phase conductor and those determining the derivative of this current intensity, an indirect transmission assembly separating from the potential of the line said frequency multipliers, mixing members, counters and computer.

Claim 16

Dependent Claim 58 words

Device according to claim 11, in which the indirect transmission assembly comprises a photoluminescent diode connected to each voltage-to-frequency converter, an optic fiber connected to said diode and to a second photoluminescent diode forming a receiving diode and an amplifier connected, on the one hand, to said receiving diode, and on the other hand, to said frequency multiplier.

Claim 17

Dependent Claim 213 words

Device according to claim 8 comprising, for each phase conductor, a voltage divider and at least one current intensity transformer, a derivating circuit connected to said transformer, a first set of switching members respectively connected to said voltage divider, to said transformer and to said derivating circuit, a first set of capacitors respectively connected to each of said switching members, a second set of switches also respectively connected, on the one hand, to each of said capacitors, and on the other hand, to at least one coding voltmeter connected to said computer, said first set of switches being directly connected by a control conductor to said clock unit and the second set of switches being connected also to said clock unit by a common control link comprising a delay circuit interposed between said common link and each switching member of said second set, so that said clock unit simultaneously closes said first set of switches during the integrating interval, then opens it at the end of this interval, said capacitors storing energy during said interval and said clock unit then successively closing the switches of said second set, so that said capacitors are thus emptied in said coding voltmeter to which they are connected, said coding voltmeter consequently transmitting data to said computer.

Claim 18

Dependent Claim 196 words

Device according to claim 13, further comprising a third set of capacitor respectively interposed between an upstream switch and a downstream switch, said upstream switches being respectively connected to the input of said first set of switches and said downstream switches each being connected to at least a coding voltmeter, itself connected to said computer, a counter for the periods of the AC circulating in the line being provided and being connected by a control conductor to an interVal counter itself connected by a control conductor to said clock unit, so that said counter for the periods causes said interval counter to count an entire number of time intervals each containing an integrating interval and corresponding to an entire number of periods of the AC and said interval counter being connected, by a control conductor and by delay circuits, to said downstream switches, whereas said upstream switches are directly connected to said interval counter, so that the capacitors connected to the latter switches store energy during a time corresponding to an entire number of periods and that said downstream switches then transmit said energy to the coding voltmeter whose data are thus brought to said computer.

Claim 19

Dependent Claim 208 words

Device according to claim 12 supplementarily comprising further, for said voltage-to-frequency converters placed at the potential of the line a circuit of electrical energy supply comprising a voltage divider connected to said line, at least one transformer fed by said voltage divider, a rectifying and filtering circuit by which a direct current under at least one voltage is supplied to said voltage-to-frequency converters, at least one accumulator battery connected to said rectifying circuit by a charge resistance, a two-position relay interposed between said transformer and said rectifying and filtering circuit, said relay having a control coil fed by said transformer so that said relay is kept in working position as long as sufficient voltage exists in the line for ensuring the supply of said voltage-to-frequency converters and the charge of said battery, an ondulating device being interposed between said battery and said relay and branched onto a rest contact of said relay, so that said ondulating device is fed by said battery when said terminal of said relay is no longer fed, and a deferred action device interposed between said battery and said ondulating device, so that the link between said battery and said ondulating device is only maintained during a given time by said deferred action device.

Claim 20

Dependent Claim 82 words

Device according to claim 15, comprising further a photoresistance permanently connected to said battery, an optic link for ensuring lumination of said photoresistance, a relay fed by said photoresistance and connected to said deferred action device for resetting said device when said photoresistance is luminated, and an electric generator, said deferred action device being associated with an air turbine to recharge said battery, and a pipe in an isolating material permitting compressed air to be sent from the ground to said turbine.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1974-07-12	1975-01-11	1975-07-13	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1978-07-12	1979-01-11	1979-07-13	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1982-07-12	1983-01-11	1983-07-13	$7700.00	Window Closed / Lapsed

Method and device for detecting and localizing phase-to-phase and phase-to-earth faults which occur in a section of a polyphase alternating current line

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