Aspects of the subject disclosure may include, for example, a waveguide system that includes a transmission device having a coupler positioned with respect to a transmission medium to facilitate transmission or reception of electromagnetic waves that transport communications data. The electromagnetic waves propagate along an outer surface of the transmission medium. A training controller detects an impairment on the transmission medium adverse to the transmission or reception of the electromagnetic waves and adjusts the electromagnetic waves to reduce the effects of the impairment on the transmission medium. Other embodiments are disclosed.

Transmission device with impairment compensation and methods for use therewith

The author presents a bibliography and survey of the literature concerned with theory and measurement of the stochastic behavior of pulsating partial-discharge (PD) phenomena that can occur when insulation is subjected to electrical stress. The types of PD phenomena considered include AC and DC generated electron avalanches, pulsating positive and negative corona in gases, and PD that occur in liquid media and in the presence of solid dielectric surfaces. The basic physical mechanisms of discharge initiation, growth, and memory propagation that determine the probability distributions for pulse occurrence times and pulse amplitudes are discussed. Consideration is also given to special problems associated with the measurement and interpretation of data on the various statistical properties of PD phenomena. >

Stochastic properties of partial-discharge phenomena

A PN modulated signal is applied to a near end (25) of a buried electrical cable (26). The signal produces an initial pulse, a second pulse of energy reflected from a fault and a third pulse representative of the far end (27) of the cable, the time/distance (t) between the second and third pulses is stored. As the PN signal is continuously applied an operator, using an antenna (62) coupled monitor (30), walks along the cable (26) noting the time/distance (t) between the initial and third pulses. When this time/distance (t) equals the stored time/distance (t) the operator is standing over the fault. If the fault is a high resistance fault a high voltage pulse is applied to the near end (25) of the cable (26, 86). The PN signal is initially sensed at a time when the fault has a low resistance because of arcing due to the high voltage pulse. To reduce stress on the cable (26, 86), the arc is initialized by a high voltage low current signal and is maintained by a low voltage high current signal.

Fault and splice finding system and method

Data associated with at least one building condition or status is sensed by one or more sensors. The data from these sensors may be sent over a data bus and received by the central computer. In addition, a modulated signal may be transmitted by one or both of the transmitters across the data bus. The modulated signal is received at the receiver, which analyzes the received modulated signal, and determines whether an intermittent fault has occurred on the data bus based upon the analyzing. For example, the receiver may compare the received signal to an expected pattern and when a discrepancy exists, an intermittent fault is determined to exist. The receiver may also determine the location of the fault based upon the analysis.

System and method of detecting and locating intermittent and other faults

Systems and methods for thermally modifying an ice-to-object interface. One system includes a power supply configured to generate a magnitude of power. The magnitude of the power is sufficient to melt an interfacial layer of ice at the interface; typically the interfacial layer has a thickness in a range one micron to one millimeter. A controller may be used to limit the duration in which power supply generates the magnitude of the power, to limit unneeded heat energy dissipation into the environment. Modulating the pulsed heating energy to the interface modifies a coefficient of friction between the object and the ice.

Systems and methods for modifying an ice-to-object interface

A method and apparatus of detecting the locations of incipient faults in an insulated power line which comprises the method steps of opening one end of the power line, if it is not suitably terminated to reflect high frequency pulses, applying an excitation voltage to the other end of the power line at an excitation point, detecting a first high frequency pulse produced by a discharge in the power line and transmitted on the power line to the excitation point, detecting a first reflection of the pulse from the open end of the power line to the point of excitation, detecting the travel time of a reflection of the first pulse from the excitation point to the open end of the power line and return to the excitation point, and dividing the time between the detection of the first pulse and the first reflected pulse by the detected travel time. The invention also provides a method and means for only detecting discharge pulses which occur in a predetermined range of magnitude of the excitation voltage and discharge pulses which reside within predetermined ranges of magnitudes. The discharge sites may be detected using either reflected voltage or current pulses.

Method and instrumentation for the detection, location and characterization of partial discharges and faults in electric power cables

A method and apparatus for locating an incipient fault at a point along the length of an insulated power line includes the application of an excitation voltage at an open end of the power line, and the signal pulse transmitted along the power line to the open end is passed through a high pass filter to remove the portion of the signal which is at a frequency below the excitation voltage and its harmonics. The filtered signal is amplified and passed through a band pass filter to remove a high frequency portion of the signal containing a large proportion of noise relative to the frequency of the partial discharge frequency from the incipient fault. This filtered signal is passed to a digital storage device adapted to be triggered by a signal of a predetermined amplitude, and the triggered digital storage device receives the amplified signal directly from the amplifier and stores digital data concerning amplitude and time for the peaks of the amplified signal for a predetermined period of time. The stored digital data is processed to identify the peaks reflecting the point of partial discharge in the power line.

Method and apparatus for the detection and location of faults and partial discharges in shielded cables

A method and apparatus for detecting the location of an incipient fault in an insulated power system which includes the application of an excitation voltage to a power line to produce a partial discharge signal pulse at a fault (34) along the power line. The surface of the power line is scanned with two axially spaced sensors (30, 32) disposed adjacent the surface of the power line, the sensors detecting the partial discharge signal pulse to produce discrete detected pulses. These detected pulses are combined to produce a combined signal having an amplitude level which reaches an extreme value when the fault is located equidistantly between the sensors. The sensors are moved along the power line until the fault is located substantially equidistantly between the sensors as indicated by the extreme amplitude level of the combined signal.

Cable partial discharge location pointer

A method and apparatus for locating an incipient fault (F) at a point along the length of an insulated power line (C) includes the application of the excitation voltage at an open end (A) of the power line (C). The signal pulse transmitted along the power line (C) to the open end (A) is passed through a high pass filter (18, 20). The filtered signal is amplified (22, 24) and passed through a band pass filter (28) to remove a high frequency portion of the signal containing a large proportion of noise relative to the frequency of the partial discharge frequency from the incipient fault (F). This filtered signal is passed to a digital storage device (32) which also receives the amplified signal directly from the amplifier (26) and stores digital data. The stored digital data is processed to identify the peaks reflecting the point of partial discharge in the power line.

Detection of location of faults in cables

An improved jacket material for insulated electric cable wherein the jacket contains one or more additives of an ion exchange resin and/or an ionic scavenging compound for neutralizing or capturing ionic impurities.

Matthew S. Mashikian

Papers

Method and instrumentation for the detection, location and characterization of partial discharges and faults in electric power cables

Method and apparatus for the detection and location of faults and partial discharges in shielded cables

Cable partial discharge location pointer

Detection of location of faults in cables

Jacket for insulated electric cable