REDUNDANT, RADIO TRANSMITTER AND RECEIVER CONTROL SYSTEMS FOR TELEMETERING SYSEMS

• US 3,706,930 A
• Filed: 11/27/1970
• Issued: 12/19/1972
• Est. Priority Date: 11/27/1970
• Status: Expired due to Term

• Current Assignee: Robert H. Harner
• Original Assignee: Robert H. Harner
• Inventors: Harner, Robert H.
• Primary Examiner(s): Murray, Richard
• Assistant Examiner(s): Leibowitz, Barry
• Application Number:
  US05/093,488
• Time in Patent Office: 753 Days
• Field of Search: 325/2,3,51,56,57,113,154,158,301,302,305 343/177,207,208 340/150,179,184,185
• US Class Current: 340/538.11
• CPC Class Codes: G01R 31/54 Testing for continuity
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72
• CPC Class Codes: H02H 1/0061 concerning transmission of signals transmission of measured quantities or switching orders; sectionalised protection involving signal transmission between at least two stations H02H7/261; comparison of the voltage or current values at two spaced portions of a single system H02H3/28; transferring the output of a sensing member to another variable G01D5/00; electrical measuring arrangements using modulation of electromagnetic waves, e.g. light beams G01R15/24, G01R15/26
• CPC Class Codes: H04B 1/74 for increasing reliability, e.g. using redundant or spare channels or apparatus replacing by standby devices for amplifiers H03F1/52, H03F1/542

Abstract

For continuity in monitoring a variable, such as current flow, in a conductor of a high voltage electric power transmission line, prime and standby radio transmitters are mounted on each conductor of a polyphase system and are arranged to operate at the same nominal but slightly different carrier frequencies and at different field strength levels. A radio receiver for each set of prime and standby radio transmitters is located at a remote point, is responsive to both frequencies and both field strength levels and is arranged to control the operation of relaying and metering equipment and to indicate the operating status of the transmitters. Additionally, prime and standby receivers for each phase conductor are located at the remote point and are arranged to be responsive to a single transmitter on each phase conductor or to prime and standby transmitters on each phase conductor operating at independent carrier frequencies or to prime and standby transmitters on each phase conductor operating at the same nominal but slightly different carrier frequencies and at different field strength levels. Prime and standby relaying and metering equipment is operated by the prime and standby radio receivers. Signals received by the prime and standby radio receivers are combined to provide an indication of the operating status of the individual receivers.

Claims

1. In a system for transmitting signals corresponding to a variable of a high voltage conductor and receiving said signals at a remote point in combination prime and standby radio transmitters on said conductor arranged to transmit simultaneously said signals by slightly different carrier frequencies and slightly different field strength levels, and a single ratio receiver at said remote point responsive to both said slightly different carrier frequencies of said slightly different field strength levels for generating a frequency variation component derived from mixing of the carrier signals, which is proportional in magnitude to the frequency difference of the carrier signals, and an amplitude variation component derived from mixing of the carrier signals, which is proportional in magnitude to the ratio of the field strengths of the carrier signals, said frequency variation component lying within the bandpass characteristics of the RF and IF component'"'"''"'"'s of the receiver.

2. In a system according to claim 1 wherein the difference in carrier frequencies is of the order of 0.010 percent and the ratio of the field strengths is of the order of 0.5.

3. In the system according to claim 1 wherein said radio receiver includes first circuit means responsive to the signals corresponding to said variable at either frequency and either field strength level for controlling the operation of a device in accordance with said variable, second circuit means responsive to said frequency variation component, and means operated by said second circuit means for indicating whether said carrier frequencies are being transmitted by said transmitters.

4. In the system according to claim 3 wherein said second circuit means comprises a sensing circuit including a relay that is energized when both carrier frequencies are being received, and said means for indicating whether said carrier frequencies are being transmitted includes a signalling device controlled by said relay.

5. In the system according to claim 3 wherein said first circuit means includes relatively low pass filter means to prevent the difference frequency between said carrier frequencies from affecting the operation of said device, and said second circuit means includes band pass filter means to prevent the modulation signal frequencies outside its pass band from affecting the operation of said indicating means.

6. In the system according to claim 1 wherein said radio receiver includes first circuit means responsive to the signals corresponding to said variable at either frequency and either field strength level for controlling the operation of a device in accordance with said variable, second circuit means respoNsive to said amplitude variation component, and means operated by said second circuit means for indicating whether said carrier frequencies are being transmitted.

7. In the system according to claim 6 wherein said second circuit means comprises a sensing circuit including a relay that is energized when both transmitters are operating, and said means for indicating whether said carrier frequencies are being transmitted includes a signalling device controlled by said relay.

8. In the system according to claim 6 wherein said first circuit means includes relatively low pass filter means to prevent the difference frequency between said carrier frequencies from affecting the operation of said device, and said second circuit means includes band pass filter means to prevent the modulation signal frequencies outside its pass band from affecting the operation of said indicating means.

9. In a system for transmitting signals corresponding to a variable of polyphase conductors of a high voltage alternating current electric power transmission line and receiving said signals at a remote point in combination radio transmitting means on each conductor arranged to transmit a signal individual to a variable thereof by a carrier frequency individual thereto, prime and standby radio receivers for each phase conductor at said remote point simultaneously responsive to the carrier frequency of the respective radio transmitting means, means individual to each prime and standby radio receiver for indicating whether it is receiving the respective carrier frequency and is capable of receiving the same, prime and standby adder means responsive respectively to said prime and standby radio receivers, and prime and standby level detector means responsive respectively to said prime and standby adder means for operating said indicating means.

10. In a system for transmitting signals corresponding to a variable of polyphase conductors of a high voltage alternating current electric power transmission line and receiving said signals at a remote point in combination radio transmitting means on each conductor arranged to transmit a signal individual to a variable thereof by a carrier frequency individual thereto, prime and standby radio receivers for each phase conductor at said remote point simultaneously responsive to the carrier frequency of the respective radio transmitting means, means individual to each prime and standby radio receiver for indicating whether it is receiving the respective carrier frequency and is capable of receiving the same, phase comparator means responsive to said prime and standby receivers for each phase, and phase level detector means responsive respectively to said phase comparator means for operating said indicating means.

11. In a system for transmitting signals corresponding to a variable of polyphase conductors of a high voltage alternating current electric power transmission line and receiving said signals at a remote point in combination radio transmitting means on each conductor arranged to transmit a signal individual to a variable thereof by a carrier frequency individual thereto, prime and standby radio receivers for each phase conductor at said remote point simultaneously responsive to the carrier frequency of the respective radio transmitting means, means individual to each prime and standby radio receiver for indicating whether it is receiving the respective carrier frequency and is capable of receiving the same, prime and standby adder means responsive respectively to said prime and standby radio receivers, phase comparator means responsive to said prime and standby receivers for each phase, prime and standby level detector means responsive respectively to said prime and standby adder means, phase level detector means responsive respectively to said phase comparator means, and prime and standby AND gates responsive respectively to said prime and standby level detector means and individually responsive to corresponding phase level detector means and have for operation thereby the respective indicating means.

12. In a system for transmitting signals corresponding to a variable of a high voltage conductor and receiving said signals at a remote point, in combination, prime and standby radio transmitters on said conductor arranged to transmit said signals at slightly different carrier frequencies and slightly different field strength levels, a radio receiver at said remote point responsive to a mixture of said signals for generating a frequency variation component derived from mixing of the carrier signals, which is proportional in magnitude to the frequency difference of the carrier signals, and an amplitude variation component derived from mixing of the carrier signals, which is proportional in magnitude to the ratio of the field strengths of the carrier signals, said frequency variation component lying within the bandpass characteristics of the RF and IF component'"'"''"'"'s of the receiver, first circuit means in said radio receiver responsive to the signals corresponding to said variable at either frequency and either field strength level for controlling the operation of a device in accordance with said variable, second circuit means in said radio receiver responsive to said frequency variation component, means operated by said second circuit means for indicating whether said carrier frequencies are being transmitted by said transmitters;

and carrier level relay control means in said radio receiver comprising prime carrier level circuit means responsive to a relatively high field strength level from said prime transmitter, a prime control relay that is energized at and above said relatively high field strength level, and a prime transmitter '"'"''"'"''"'"''"'"'OFF'"'"''"'"''"'"''"'"' signalling device controlled by said prime control relay, standby carrier level circuit means responsive to a relatively low field strength level from said standby transmitter, a standby control relay that is energized at and above said relatively low field strength level, and a standby transmitter '"'"''"'"''"'"''"'"'OFF'"'"''"'"''"'"''"'"' signalling device controlled by said standby control relay.

13. In a system for transmitting signals corresponding to a variable of high voltage conductor and receiving said signals at a remote point, in combination, prime and standby radio transmitters on said conductor arranged to transmit said signals at slightly different carrier frequencies and slightly different field strength levels, a radio receiver at said remote point responsive to a mixture of said signals for generating a frequency variation component derived from mixing of the carrier signals, which is proportional in magnitude to the frequency difference of the carrier signals, and an amplitude variation component derived from mixing of the carrier signals, which is proportional in magnitude to the ratio of the field strengths of the carrier signals, said frequency variation component lying within the bandpass characteristics of the RF and IF component'"'"''"'"'s of the receiver, first circuit means in said radio receiver responsive to the signals corresponding to said variable at either frequency and either field strength level for controlling the operation of a device in accordance with said variable, second circuit means in said radio receiver responsive to said frequency variation component, means operated by said second circuit means for indicating whether said carrier frequencies are being transmitted by said transmitters, said first circuit means including relatively low pass filter means to prevent the difference frequency between said carrier frequencies from affecting the operation of said device, said second circuit means including band pass filter means to prevent the modulation signal frequencies outside its pass band from affecting the operation of said indicating means, and de-emphasis network means connected in said second circuit means in advance of said band pass filter means to render operation of said second circuit means independent of amplitude variations due to said carrier frequency difference.

14. In a system for transmitting signals corresponding to a variable of high voltage conductor and receiving said signals at a remote point, in combination, prime and standby radio transmitters on said conductor arranged to transmit said signals at slightly different carrier frequencies and slightly different field strength levels, a radio receiver at said remote point responsive to a mixture of said signals for generating a frequency variation component derived from mixing of the carrier signals, which is proportional in magnitude to the frequency difference of the carrier signals, and an amplitude variation component derived from mixing of the carrier signals, which is proportional in magnitude to the ratio of the field strengths of the carrier signals, said frequency variation component lying within the bandpass characteristics of the RF and IF component'"'"''"'"'s of the receiver, first circuit means in said radio receiver responsive to the signals corresponding to said variable at either frequency and either field strength level for controlling the operation of a device in accordance with said variable, second circuit means in said radio receiver responsive to said amplitude variation component, means operated by said second circuit means for indicating whether said carrier frequencies are being transmitted;

and carrier level relay control means in said radio receiver comprising prime carrier level circuit means responsive to a relatively high field strength level from said prime transmitter, a prime control relay that is energized at and above said relatively high field strength level, and a prime transmitter '"'"''"'"''"'"''"'"'OFF'"'"''"'"''"'"''"'"' signalling device controlled by said prime control relay, standby carrier level circuit means responsive to a relatively low field strength level from said standby transmitter, a standby control relay that is energized at and above said relatively low field strength level, and a standby transmitter '"'"''"'"''"'"''"'"'OFF'"'"''"'"''"'"''"'"' signalling device controlled by said standby control relay.

15. In a system for transmitting signals corresponding to a variable of polyphase conductors of a high voltage alternating current electric power transmission line and receiving said signals at a remote point, in combination, radio transmitting means on each conductor arranged to transmit a signal individual to a variable thereof by a carrier frequency individual thereto, prime and standby radio receivers for each phase conductor at said remote point simultaneously responsive to the carrier frequency of the respective radio transmitting means, means individual to each prime and standby radio receiver for indicating whether it is receiving the respective carrier frequency and is capable of receiving the same, said radio transmitting means comprising prime and standby radio transmitters on each conductor arranged to transmit said signals at different frequencies of the order of 0.010 percent, and different field strength levels on the order of a ratio of 0.5 and the corresponding prime and standby radio receivers each being responsive to said different frequencies and field strength levels.