Control system for an electrical power line

Claim 2

For use with an electrical power system, an improved control system comprising: a. transmitting means having an output adapted to be connected to a communication channel at a first location on said power system, said transmitting means comprising: 1. means for transmitting a pilot frequency over said communication channel; 2. means for transmitting two guard frequencies over said communication channel in response to proper operation of said power system; 3. and means for transmitting two trip frequencies over said communication channel in place of said two guard frequencies in response to improper operation of said power system; b. and receiving means having an input adapted to be connected to said communication channel at a second location on said power system, said receiving means comprising: 1. a narrow band filter connected to said receiving means input for receiving substantially only said pilot frequency from said communication channel; 2. a medium band filter connected to said receiving means input for receiving a medium band of frequencies other than said pilot frequency from said communication channel; 3. a wide band filter connected to said receiving means input for receiving a wide band of frequencies from said communication channel; 4. a squelch receiver having inputs connected to said narrow band filter, said medium band filter, and said wide band filter respectively, said squelch receiver producing an unsquelch signal only in response to receiving said pilot frequency at a level having a predetermined relation with the level of said medium band frequencies and said wide band frequencies, and producing a squelch signal otherwise; 5. first and second trip frequency filters connected to said receiving means input for receiving said first and second trip frequencies respectively; 6. output means respectively connected to said first and second trip frequency filters and to said squelch receiver for producing respective trip outputs only in response to said unsquelch signal and in response to said two trip frequencies; 7. and means connected to said output means for utilizing said trip outputs.

Claim 3

For use with an electrical power system, an improved control system comprising: a. transmitting means having an output adapted to be connected to a communication channel at a first location on said power system, said transmitting means comprising:

Claim 4

For use with an electrical power system, an improved control system comprising: a. transmitting means having an output adapted to be connected to a communication channel at a first location on said power system, said transmitting means comprising:

Claim 5

means for transmitting a pilot frequency over said communication channel;

Claim 6

means for transmitting a pilot frequency over said communication channel;

Claim 7

a narrow band filter connected to said receiving means input for receiving substantially only said pilot frequency from said communication channel;

Claim 8

a narrow band filter connected to said receiving means input for receiving substantially only said pilot frequency from said communication channel;

Claim 11

means for transmitting two guard frequencies over said communication channel in response to proper operation of said power system;

Claim 12

means for transmitting two guard frequencies over said communication channel in response to proper operation of said power system;

Claim 13

The improved control arrangement of claim 1 wherein said squelch receiver further comprises means for controlling the respective levels for said pilot frequencies, said medium band of frequencies, and said wide band of frequencies as an inverse function of the received level of said pilot frequency.

Claim 14

The improved control system of claim 1 wherein said pilot frequency transmitting means supplies said pilot frequency at a higher level in response to improper operation of said power system.

Claim 15

and means for transmitting two trip frequencies over said communication channel in place of said two guard frequencies in response to improper operation of said power system; b. and receiving means having an input adapted to be connected to said communication channel at a second location on said power system, said receiving means comprising:

Claim 16

and means for transmitting two trip frequencies over said communication channel in place of said two guard frequencies in response to improper operation of said power system; b. and receiving means having an input adapted to be connected to said communication channel at a second location on said power system, said receiving means comprising:

Claim 17

a wide band filter connected to said receiving means input for receiving a wide band of frequencies from said communication channel;

Claim 18

a wide band filter connected to said receiving means input for receiving a wide band of frequencies from said communication channel;

Claim 19

first and second trip frequency filters connected to said receiving means input for receiving said first and second trip frequencies respectively;

Claim 20

first and second trip frequency filters connected to said receiving means input for receiving said first and second trip frequencies respectively;

Claim 21

An improved control arrangement for power lines and the like comprising: a. input means adapted to be connected to a communication channel for receiving signals therefrom, said signals comprising a pilot frequency, first guard and trip frequencies, and second guard and trip frequencies; b. a pilot filter connected to said input means for passing substantially only said pilot frequency; c. a medium band filter connected to said input means for passing a relatively small band of frequencies above and below said pilot frequency and for rejecting said pilot frequency; d. a wide band filter connected to said input means for passing a relatively wide band of frequencies including said small band of frequencies, said pilot frequency, said first trip filter band of frequencies, and said second trip filter band of frequencies; e. first and second variable attenuators each having an input, an output, and a control; f. means connecting said first attenuator input to said pilot filter and said second attenuator input to said medium band filter and said wide band filter; g. a gain control circuit having an input and an output; h. means connecting said gain control input to said first attenuator output and said gain control output to both of said attenuator controls in a negative feedback fashion; i. a comparator circuit having two inputs and an output; j. means respectively connecting said comparator inputs to said first and second variable attenuator outputs; k. said comparator producing an unsquelch signal at its output in response to said pilot frequency level being within a predeterMined compared range of said wide band frequency level and beyond a predetermined compared range of said medium band frequency level, and producing a squelch signal in response to said pilot signal level being beyond said predetermined compared range of said wide band frequency level or being within said predetermined compared range of said medium band frequency level; l. a first trip filter having an input connected to said input means and having an output for providing substantially only said first guard and trip frequencies and the band of frequencies therebetween; m. a second trip filter having an input connected to said input means and having an output for providing substantially only said second guard and trip frequencies and the frequency band therebetween; n. first and second frequency discriminators each having an input and a trip frequency output; o. means respectively connecting said first and second discriminator inputs to said outputs of said first and second trip filters; p. means connecting said comparator output to said discriminators for blocking signals at said discriminator trip frequency outputs in response to a squelch signal and for passing signals at said discriminator trip frequency outputs in response to an unsquelch signal; q. and means connected to said discriminator trip frequency outputs for producing a utilization signal for tripping a circuit breaker or the like in response to the simultaneous occurrence of signals at said discriminator trip frequency outputs.

Claim 22

An improved control arrangement for power lines and the like comprising: a. input means adapted to be connected to a communication channel for receiving signals therefrom, said signals comprising a pilot frequency, first guard and trip frequencies, and second guard and trip frequencies; b. a pilot filter connected to said input means for passing substantially only said pilot frequency; c. a medium band filter connected to said input means for passing a relatively small band of frequencies above and below said pilot frequency and for rejecting said pilot frequency; d. a wide band filter connected to said input means for passing a relatively wide band of frequencies including said small band of frequencies, said pilot frequency, said first trip filter band of frequencies, and said second trip filter band of frequencies; e. first and second variable attenuators each having an input, an output, and a control; f. means connecting said first attenuator input to said pilot filter and said second attenuator input to said medium band filter and said wide band filter; g. a gain control circuit having an input and an output; h. means connecting said gain control input to said first attenuator output and said gain control output to both of said attenuator controls in a negative feedback fashion; i. a comparator circuit having two inputs and an output; j. means respectively connecting said comparator inputs to said first and second variable attenuator outputs; k. said comparator producing an unsquelch signal at its output in response to said pilot frequency level being within a predeterMined compared range of said wide band frequency level and beyond a predetermined compared range of said medium band frequency level, and producing a squelch signal in response to said pilot signal level being beyond said predetermined compared range of said wide band frequency level or being within said predetermined compared range of said medium band frequency level; l. a first trip filter having an input connected to said input means and having an output for providing substantially only said first guard and trip frequencies and the band of frequencies therebetween; m. a second trip filter having an input connected to said input means and having an output for providing substantially only said second guard and trip frequencies and the frequency band therebetween; n. first and second frequency discriminators each having an input and a trip frequency output; o. means respectively connecting said first and second discriminator inputs to said outputs of said first and second trip filters; p. means connecting said comparator output to said discriminators for blocking signals at said discriminator trip frequency outputs in response to a squelch signal and for passing signals at said discriminator trip frequency outputs in response to an unsquelch signal; q. and means connected to said discriminator trip frequency outputs for producing a utilization signal for tripping a circuit breaker or the like in response to the simultaneous occurrence of signals at said discriminator trip frequency outputs.

Claim 23

The improved control arrangement of claim 5 and further comprising: a. input means adapted to be connected to sensing equipment on the power line for receiving a trip signal in response to an undesired condition on said power line; b. transmitting means connected to said input means for producing a pilot frequency at a first level, a first guard frequency, and a second guard frequency in the absence of said trip signal; and for producing said pilot frequency at a level higher than said first level, a first trip frequency in place of and higher than said first guard frequency, and a second trip frequency in place of and lower than said second guard frequency in response to said trip signal; c. and output means connected to said transmitting means and adapted to be connected to a communication channel for applying said frequencies to said communication channel.

Claim 24

output means respectively connected to said first and second trip frequency filters and to said squelch receiver for producing respective trip outputs only in response to said unsquelch signal and in response to said two trip frequencies;

Claim 25

output means respectively connected to said first and second trip frequency filters and to said squelch receiver for producing respective trip outputs only in response to said unsquelch signal and in response to said two trip frequencies;

Claim 26

and means connected to said output means for utilizing said trip outputs.

Claim 27

and means connected to said output means for utilizing said trip outputs.