US3579040A — Desensitizing circuit for differential relay

Claim 1

Independent Claim 376 words

In a protective relaying apparatus for an electrical apparatus adapted to pass electrical energy therethrough in substantially undiminished magnitude, a first control means having a first operate input means and a first restraint input means and a first switch means, said control means acting to place said switch means in a first closed circuit-controlling condition solely when the ratio of energization of said operate means with respect to said restraint means is greater than a first predetermined magnitude, a first current-responsive device associated with the input side of said electrical apparatus and having a first output quantity the magnitude of which is a function of the magnitude of the current in said input side, a second current-responsive device associated with the output side of said electrical apparatus and having a second output quantity the magnitude of which is a function of the magnitude of the current in said output side, a first network energized as a function of the difference in magnitudes of said first and second output quantities and providing a third output quantity of a magnitude proportional to said difference in magnitudes, first circuit means connecting said first network to said operate input means for energization thereof by said third output quantity, a second network energized as a function of the magnitude of one of said first and second output quantities and providing a fourth output quantity of a magnitude proportional to said one output quantity, an operating condition responsive device connected to said first restraint input means, a fifth output quantity supplying network controlled by said operating condition responsive device and having an output circuit energized to supply a fifth output quantity as a consequence of the actuation of said operating condition responsive device, said operating condition responsive device being actuated to provide said fifth output quantity solely when the magnitude of the signal applied thereto is above a predetermined magnitude, and means connecting said output circuit and said second network to said restraint input means whereby said restraint means is energized as a function of the combination of said fourth and said fifth output quantities, the magnitude of said fifth quantity being independent of the increase in the magnitude of the signal applied to said responsive device above said predetermined magnitude thereof.

Claim 2

Dependent Claim 376 words

In a protective relaying apparatus for an electrical apparatus adapted to pass electrical energy therethrough in substantially undiminished magnitude, a first control means having a first operate input means and a first restraint input means and a first switch means, said control means acting to place said switch means in a first closed circuit-controlling condition solely when the ratio of energization of said operate means with respect to said restraint means is greater than a first predetermined magnitude, a first current-responsive device associated with the input side of said electrical apparatus and having a first output quantity the magnitude of which is a function of the magnitude of the current in said input side, a second current-responsive device associated with the output side of said electrical apparatus and having a second output quantity the magnitude of which is a function of the magnitude of the current in said output side, a first network energized as a function of the difference in magnitudes of said first and second output quantities and providing a third output quantity of a magnitude proportional to said difference in magnitudes, first circuit means connecting said first network to said operate input means for energization thereof by said third output quantity, a second network energized as a function of the magnitude of one of said first and second output quantities and providing a fourth output quantity of a magnitude proportional to said one output quantity, an operating condition responsive device connected to said first restraint input means, a fifth output quantity supplying network controlled by said operating condition responsive device and having an output circuit energized to supply a fifth output quantity as a consequence of the actuation of said operating condition responsive device, said operating condition responsive device being actuated to provide said fifth output quantity solely when the magnitude of the signal applied thereto is above a predetermined magnitude, and means connecting said output circuit and said second network to said restraint input means whereby said restraint means is energized as a function of the combination of said fourth and said fifth output quantities, the magnitude of said fifth quantity being independent of the increase in the magnitude of the signal applied to said responsive device above said predetermined magnitude thereof.

Claim 3

Dependent Claim 33 words

The combination of claim 1 iN which said operating condition responsive device is a voltage-responsive device and is actuated when a voltage greater than a predetermined magnitude is applied to said electrical apparatus.

Claim 4

Dependent Claim 90 words

The combination of claim 2 in which the ratio of the input current to the output current at said electrical apparatus is of a second predetermined magnitude substantially equal to the ratio of the output voltage to the input voltage at said electrical apparatus, the ratio of the magnitude of said current function of said first current device to the magnitude of said current function of said second current device being equal to the reciprocal of said second predetermined magnitude, and said fifth quantity being of a substantially constant magnitude.

Claim 5

Dependent Claim 38 words

The combination of claim 3 in which said first and second quantities are alternating polarity quantities, said fourth quantity is a rectified alternating polarity quantity and said fifth quantity is a unidirectional polarity quantity of substantially constant magnitude.

Claim 6

Dependent Claim 41 words

The combination of claim 4 in which said fourth quantity and said fifth quantity are voltage quantities and in which said second network and said fifth output quantity network each includes asymmetric current flow devices preventing the interchange of current therebetween.

Claim 7

Dependent Claim 275 words

The combination of claim 3 in which said first and second current-responsive devices comprise first and second current transformers, said second network comprises first and second transactors, said transactors primary and secondary windings, said primary windings of said transactors and said secondary windings of said current transformers being connected in series, said second network further including first and second rectifier means individually connected across the individual secondary windings of said first and second transactors respectively and including a circuit connecting the rectified current output connections of said rectifier means in parallel circuit, the output voltage of said parallelly connected rectifier means being said fourth output quantity, said first network including a third transactor having its primary winding connected in parallel with said secondary winding of said first current transformer and said primary winding of said first transactor and also in parallel with said secondary winding of said second current transformer and said primary winding of said second transactor, and a third rectifier means connected across the secondary winding of said third transactor, said third output quantity being the output voltage of said third rectifier means, said first circuit means being the connections of the rectified current output connections of said third rectifier means to said operate input means, said fifth output supplying network comprising a source of substantially constant unidirectional potential and an asymmetric current flow device, said means connecting said output circuit and said second network to said restraint means including the circuit connecting said output connections of said first and second rectifier means to said restraint means in parallel with the circuit connecting said source of substantially constant potential through said asymmetric device.

Claim 8

Dependent Claim 168 words

The combination of claim 6 in which there is provided a second control means having a second operate input means and a first restraint input means and a first switch means, a breaker control circuit including said first and second switch means, a fourth transactor having a primary winding connected in series with said primary winding of said third transactor, fourth and fifth rectifier means, first and second tuned networks, said second network being tuned to pass a harmonic of the frequency to which said first network is tuned to pass, means connecting the secondary winding of said fourth transactor through said fourth rectifier means and said first tuned network to said second operate input means, means connecting said secondary winding of said fourth transactor through said fifth rectifier Means and said second tuned network to said second restraint input means, said electrical apparatus including magnetizable material which tends to saturate at potentials applied thereto greater than said predetermined magnitude at which said fifth output quantity is supplied.

Claim 9

Dependent Claim 216 words

In a protective relaying apparatus of the type having an output circuit energized when the ratio between a first signal applied to an operative element and a second signal applied to a restraint element exceeds a predetermined magnitude, said first signal having a magnitude which is a function of the difference between the magnitudes of a first characteristic of each of a pair alternating potential quantities, said second signal having a magnitude which is a function of the one of said pair of quantities having the greater magnitude, the improvement comprising a control network having an input means and an output means and a control means effective to energize said output means with a third signal solely when the magnitude of a fourth signal applied to said input means is greater than a first desired amount, means energized by a second characteristic of one of said alternating potential quantities and effective when the magnitude of said second characteristic exceeds a desired amount to provide a magnitude of said fourth signal of said first desired amount, means connecting said last-named means to said input means for supply of said fourth signal thereto, and means connecting said output means to said restraint element, said restraint element being effective when energized by said third signal to increase said ratio.

Claim 10

Dependent Claim 216 words

In a protective relaying apparatus of the type having an output circuit energized when the ratio between a first signal applied to an operative element and a second signal applied to a restraint element exceeds a predetermined magnitude, said first signal having a magnitude which is a function of the difference between the magnitudes of a first characteristic of each of a pair alternating potential quantities, said second signal having a magnitude which is a function of the one of said pair of quantities having the greater magnitude, the improvement comprising a control network having an input means and an output means and a control means effective to energize said output means with a third signal solely when the magnitude of a fourth signal applied to said input means is greater than a first desired amount, means energized by a second characteristic of one of said alternating potential quantities and effective when the magnitude of said second characteristic exceeds a desired amount to provide a magnitude of said fourth signal of said first desired amount, means connecting said last-named means to said input means for supply of said fourth signal thereto, and means connecting said output means to said restraint element, said restraint element being effective when energized by said third signal to increase said ratio.

Claim 11

Dependent Claim 20 words

The combination of claim 8 in which the magnitude of said third signal is of a substantially constant magnitude amount.

Claim 12

Dependent Claim 66 words

The combination of claim 9 in which said second signal is a unidirectional electric current of a magnitude determined by the magnitude of said one quantity, said one quantity being a current quantity, said third signal being a unidirectional current, said fourth signal being a signal having its magnitude determined by the magnitude of the voltage of a selected one of said pair of alternating quantities.

Claim 13

Dependent Claim 261 words

In a differential protective relaying apparatus for a power-transferring device adapted to pass electrical energy therethrough, first and second input means adapted to provide first and second electrical measuring quantities having magnitudes which are responsive to first and second energizing quantities which have magnitudes related to the input and output power of the transferring device, circuit means interconnecting said first and said second input means and having output terminals energized with an output quantity the magnitude of which changes with a change in the difference in magnitude between the magnitude of said first electrical measuring quantity applied by said first input means and the magnitude of a second electrical measuring quantity applied by said second input means, a switch means, a first electrical network connected between said output terminals and said switch means and effective to provide a first actuating signal to said switch means which changes in magnitude with a change in magnitude of said output quantity, a third input means adapted to provide a third electrical measuring quantity having a magnitude which is responsive to a third energizing quantity at one side of said transferring device, said third energizing quantity being a different quantity from said first and second energizing quantities, and a second electrical network interconnecting said third input means and said switch means and effective to provide an altering signal of a magnitude independent of the magnitude of said third energizing quantity and solely at magnitudes of said third energizing quantity above a predetermined magnitude to alter the actuation of said switch means by said electrical network.

Claim 14

Dependent Claim 261 words

In a differential protective relaying apparatus for a power-transferring device adapted to pass electrical energy therethrough, first and second input means adapted to provide first and second electrical measuring quantities having magnitudes which are responsive to first and second energizing quantities which have magnitudes related to the input and output power of the transferring device, circuit means interconnecting said first and said second input means and having output terminals energized with an output quantity the magnitude of which changes with a change in the difference in magnitude between the magnitude of said first electrical measuring quantity applied by said first input means and the magnitude of a second electrical measuring quantity applied by said second input means, a switch means, a first electrical network connected between said output terminals and said switch means and effective to provide a first actuating signal to said switch means which changes in magnitude with a change in magnitude of said output quantity, a third input means adapted to provide a third electrical measuring quantity having a magnitude which is responsive to a third energizing quantity at one side of said transferring device, said third energizing quantity being a different quantity from said first and second energizing quantities, and a second electrical network interconnecting said third input means and said switch means and effective to provide an altering signal of a magnitude independent of the magnitude of said third energizing quantity and solely at magnitudes of said third energizing quantity above a predetermined magnitude to alter the actuation of said switch means by said electrical network.

Claim 15

Dependent Claim 27 words

The combination of claim 11 in which said first and second energizing quantities are current derived quantities, and said third energizing quantitY is a voltage derived quantity.

Claim 16

Dependent Claim 48 words

The combination of claim 12 in which said second electrical network acts to alter the actuation of said switch means to increase the difference in magnitude between the magnitude of said first electrical quantity and the magnitude of said second electrical quantity required to actuate said switch means.

Claim 17

Dependent Claim 57 words

The combination of claim 11 in which said switch means is provided with an operate and a restraint winding, said first electrical network being connected to energize said operate winding, said second electrical network being connected to reenergize said restraint winding, said second electrical network being effective to supply a second actuating signal to said restraint winding.

Claim 18

Dependent Claim 16 words

The combination of claim 14 in which said second actuating signal is of a constant magnitude.

Claim 19

Dependent Claim 72 words

The combination of claim 15 in which said power-transferring device is a transformer having first and second windings magnetically coupled together by a flux-carrying member, said first input means being energized in accordance with the current in said first winding, said third input means being energized in accordance with the voltage applied to one of said windings, said second input means being energized in accordance with the current in said second winding.

Claim 20

Dependent Claim 48 words

The combination of claim 16 in which said second network includes a relay having a coil connected to be energized by the voltage applied to said one winding, said relay having normally open contacts closed by a predetermined energization of said coil to supply said second actuating signal.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1974-05-17	1974-11-16	1975-05-18	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1978-05-17	1978-11-16	1979-05-18	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1982-05-17	1982-11-16	1983-05-18	$7700.00	Window Closed / Lapsed

Desensitizing circuit for differential relay

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag