# US 8,988,099 B2 · On-line time domain reflectometer system

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- Number: US 8,988,099 B2
- Document ID: US8988099B2
- Status: Granted
- Kind: B2
- Application number: 12/820,886
- Filed: 2010-06-22
- Published: 2011-02-24
- Granted: 2015-03-24
- Earliest claimed: 2009-06-22
- Assignees: UTILX Corporation
- Applicants: Nelson Hall; William R. Stagi
- Inventors: Nelson Hall; William R. Stagi
- Web page: https://patentgrep.com/patent/US8988099B2

## CPC

- G01R 31/11: using pulse reflection methods
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

A number of TDR systems and testing methods are provided that improve the quality and accuracy of information collected when propagating a signal along a length of cable in order to pinpoint specific anomalies. One or more of the TDR systems includes, for example, a computing device, a pulse generator, and at least one capacitive test sensor. The at least one capacitive test sensor transmits/receives pulses to/from a power system component, such as an insulated power cable, in a capacitive manner.

## Claims

### Claim 1

An apparatus for testing an electrical power system for anomalies, comprising:
a computing device;
a pulse generator having an output impedance greater than 500 ohms, the pulse generator configured to generate a pulse upon reception of a command signal from the computing device;
one or more capacitive test sensors configured to be capacitively coupled to an on-line power component of the electrical power system, wherein at least one of the one or more capacitive test sensors receives the pulse generated by the pulse generator.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the one or more sensors include a first sensor coupled with the pulse generator that transmits a test pulse to the on-line power component and a second sensor coupled with the computing device that receives a reflected pulse from the on-line power component and transmits the reflected pulse to the computing device.

### Claim 3 (depends on 2)

The apparatus of claim 2, further comprising an amplifier coupled in series between the second sensor and the computing device.

### Claim 4 (depends on 3)

The apparatus of claim 3, wherein the amplifier has an input impedance of greater than 500 ohms.

### Claim 5 (depends on 3)

The apparatus of claim 3, wherein the amplifier is disposed within two inches from the second sensor.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein the computing device and the pulse generator are disposed in a portable unitary housing.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein the pulse generator has an output impedance greater than 1000 ohms.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein the on-line power component is an insulated power cable.

### Claim 9 (depends on 1)

The apparatus of claim 1, wherein the sensor is integrated into a power cable termination elbow.

### Claim 10 (depends on 8)

The apparatus of claim 8, wherein the insulated power cable includes an insulated medium voltage power transmission cable.