US 4,786,862 AGranted

Watchdog circuit for transmission line sensor module

AssigneeNiagara Mohawk Power Corporation

InventorRichard L. Sieron

Life of this patent

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Abstract

A self contained sensor module mounted on a power transmission line. The module is capable of measuring various parameters such as line current, voltage, conductor temperature, and ambient temperature. The parameter values are processed by sensor electronics which digitize and periodically transmit the values to a ground receiver. The sensor electronics include MOS integrated circuits which are sensitive to fluctuations in supply voltage and which may enter a power-fail state or latch up as a result of such fluctuations. The module contains watchdog circuitry which monitors the operation of the module. If an interruption in the module's normal operating sequence occurs, the watchdog circuit resets the MOS integrated circuits by initiating a power down/power up sequence. The module further includes current limiting circuitry that reduces the integrated circuit's supply voltage in response to the failure of a circuit that is not critical to the module's normal operating sequence.

Claims9

Dependent claims

A device for monitoring at least one parameter of a power transmission line for transmitting alternating current comprising:

means for sensing values of said parameters;
means coupled to said sensing means for processing said values;
memory means coupled to said processing means for storing said processed values;
means for deriving energy from said transmission line for powering said device;
means coupled to said means for deriving energy from said transmission line for converting alternating current into direct current;
means coupled to said means for converting for supplying power to said processing means and said memory means;
means for controlling said means for supplying power to said processing means and said memory means;
said means for controlling including means for receiving a periodic signal indicating normal device operation and being responsive to said periodic signal for continuously enabling said means for supplying power to supply power to said processing means and said memory means;
and
said means for controlling further including means responsive to sustained absence of said periodic signal indicating abnormal device operation for disabling said means for supplying power to said processing means and said memory means for a fixed time period and for subsequently enabling said means for supplying power to said processing means and said memory means;
whereby
said processing means and said memory means are powered down and subsequently powered up following an indication of abnormal device operation.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 06/872,011Filed 9 Jun 1986
Granted: 22 Nov 1988
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H01F 38/22
Instruments transformers: for single phase AC
G01R 1/36
Details of instruments or arrangements of the types included in groups G01R5/00 - G01R13/00 and G01R31/00: overload-protection arrangements or…
G01R 15/142
Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks: arrangements for simultaneous measurements of…
G01R 15/26
Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks: using modulation of waves other than light,…