US 5,181,026 AGranted

Power transmission line monitoring system

AssigneeGranville Group, Inc., The

InventorJ. Michael Granville

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Abstract

An Electric Power Line Monitoring System in which a single line measuring system station can measure all of the power parameters of both voltage and phase angle plus ambient and line temperatures. The measuring station can be secured to the power line without the need for shutting down the line. The measured data is transmitted from the measuring station on the power line to a ground receiving and data processing station. The system measures true RMS voltage and current values, RMS phase angle along with ambient and line temperatures which are digitized and transmitted through a digital fiber optic data link. The fiber optic data transmission line can be a flexible fiber optic cable assembly or a rigid fiber optic bushing assembly for supporting a long phase conductor that also contains a long resistive link of a voltage sensor voltage divider. The resistive link is constructed of materials that have a high precision resistance tolerance and low temperature coefficients of resistance that improved the accuracy of the voltage sensor.

Claims44

Dependent claims

A power transmission line monitoring system comprising;

current sampling means for sampling current on a power transmission line;
rectifying means for rectifying the output of said current sampling means;
power supply means connected to the output of said rectifying means for producing regulated filtered electrical power;
line voltage sensing means connected to said power transmission line, said line voltage sensing means including a voltage divider comprised of a small resistance connected to said power transmission line in series with a very large resistance connected to earth ground;
signal processing means for receiving and processing the data output of said line voltage sensing means, signal processing means including data processing and data transmission means for transmitting said data output of said line voltage sensing means across the line to ground voltage gradient to a ground receiving and data processing station located remotely from said power transmission line, said data transmitting means comprising a fiber optic data transmission cable that includes said very large resistance of said voltage divider;
voltage divider current loss measuring circuit means for measuring current loss across said voltage divider by the continuous measurement and comparison of the current magnitude at the power line end of said line voltage sensing voltage divider with the current magnitude at the earth ground end of said line voltage sensing voltage divider, said comparison data processing performed at said ground receiving and data processing station, said voltage divider power line end current magnitude measured by said line voltage sensing means, and said voltage divider earth ground end current magnitude measured by a voltage divider earth ground end current sensing circuit means, said voltage divider earth ground end current sensing circuit means being part of said ground receiving and data processing station;
and
a common system return connecting said current sampling means, said rectifying means, said power supply means, said line voltage sensing means, and said signal processing means to said power transmission line whereby system circuits are isolated from earth ground by using the power transmission line as a reference and as the common system circuitry return.

5 more elements

A power transmission line monitoring system comprising;

current sampling means for sampling current on a transmission line;
rectifying means for rectifying the output of said current sampling means;
power supply means connected to the output of said rectifying means for producing regulated filtered electrical power;
line current sensing means connected to said rectifying means for sensing line current;
signal processing means for receiving and processing the data output of said line current sensing means, signal processing means including data processing and data transmission means for transmitting said data output of said line current sensing means to a ground receiving and data processing station located remotely from said power transmission line, said data transmission means comprising a fiber optic data transmission cable;
and
a common system return connecting said current sampling means, said rectifying means, said power supply means, said line current sensing means, and said signal processing means to said power transmission line whereby system circuits are isolated from earth ground by using the power transmission line as a reference and as the common system circuitry return.

4 more elements

A power transmission line monitoring system comprising;

current sampling means for sampling current on a transmission line;
rectifying means for rectifying the output of said current sampling means;
power supply means connected to the output of said rectifying means for producing regulated filtered electrical power;
line temperature sensing means connected to said power transmission line for sensing power transmission line phase conductor temperature;
signal processing means for receiving and processing the data output of said line temperature sensing means, signal processing means including data processing and data transmission means for transmitting said data output of said line temperature sensing means to a ground receiving and data processing station located remotely from said power transmission line, said data transmission means comprising a fiber optic data transmission cable;
and
a common system return connecting said current sampling means, said rectifying means, said power supply means, said line temperature sensing means, and said signal processing means to said power transmission line whereby system circuits are isolated from earth ground by using the power transmission line as a reference and as the common system circuitry return.

4 more elements

A power transmission line monitoring system comprising;

current sampling means for sampling current on a power transmission line;
rectifying means for rectifying the output of said current sampling means;
power supply means connected to the output of said rectifying means for producing regulated filtered electrical power;
line current sensing means connected to said rectifying means for sensing line current;
line voltage sensing means connected to said power transmission line, said line voltage sensing means including a voltage divider comprised of a small resistance connected to said power transmission line in series with a very large resistance connected to earth ground;
line electrostatic field meter means for measuring the line electric field phasor;
signal processing means for receiving the data output of and for processing the data output of said line current sensing means, said line voltage sensing means, and said line electrostatic field meter means, said signal processing means including data processing and data transmitting means for transmitting said data output across the line to ground voltage gradient to a ground receiving and data processing station located remotely from said power transmission line, said data transmitting means comprising a fiber optic data transmission cable that includes said very large resistance of said voltage divider;
voltage divider current loss measuring circuit means for measuring current loss across said voltage divider by the continuous measurement and comparison of the current magnitude at the power line end of said line voltage sensing voltage divider with the current magnitude at the earth ground end of said line voltage sensing voltage divider, said comparison data processing performed at said ground receiving and data processing station, said voltage divider power line end current magnitude measured by said line voltage sensing means, and said voltage divider earth ground end current magnitude measured by a voltage divider earth ground end current sensing circuit means, said voltage divider earth ground end current sensing circuit means part of said ground receiving and data processing station;
and
a common system return connecting said current sampling means, said rectifying means, said power supply means, said line current sensing means, said line voltage sensing means, said line electrostatic field meter means, and said signal processing means to said power transmission line whereby system circuits are isolated from earth ground by using the power transmission line as a reference and as the common system circuitry return.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/632,249Filed 19 Dec 1990 · continuation in part
Priority: 12 Jan 1990
Granted: 19 Jan 1993
Term ends: Not estimatedThe source records don’t support an estimate.

Classification18 codes

G01R 21/133
Arrangements for measuring electric power or power factor: by using digital technique
G01R 15/183
Using inductive devices, e.g. transformers: using transformers with a magnetic core
H02H 1/0069
Concerning transmission of signals: by means of light or heat rays
H02H 1/06
Details of emergency protective circuit arrangements: arrangements for supplying operative power