Patent Description:
It is known to provide an inline, L-shaped, or T-shaped adapter to connect a high voltage electrical cable (e.g., one rated at above about <NUM> kV) to a transformer, for example. The adapter usually has one inwardly-tapering socket in one arm thereof that is a push fit onto a bushing of the transformer, and receives the terminated end of the electrical cable in another arm aligned with or at right angles thereto. The socket has an electrical contact (male or female) for cooperating with the contact (respectively female or male) of the bushing. The electrical cable may be a push-fit into the other arm, or it may be connected externally of the adapter to a terminal that is molded thereinto, as disclosed in <CIT>. Other adapters, usually of T-shape, have the bushing and cable arms at right angles to each other, and a further arm with a socket aligned with the bushing arm. Such further arm is closed by a removable plug that may allow access to connect the cable mechanically and electrically to the bushing.

It is desirable to measure the temperature of high voltage electrical cable connectors in order to detect whether a connector may be overheating, which can lead to failure. Thermocouples have conventionally been used to measure connector temperatures. Unfortunately, it may be difficult to connect a thermocouple wire to an energized cable accessory as it may cause a short circuit. In addition, Infrared (IR) cameras have been used to measure connector temperatures. Unfortunately, typical high voltage connectors are hidden beneath the thick insulation of a cable accessory. As such, a direct temperature reading via an IR camera may be difficult to obtain.

<CIT> discloses a cable connection assembly including an adaptor body in which there is a connector for an electrical cable to be terminated to. An RFID temperature measuring tag is secured to the connector, and includes a temperature sensor and an RFID tag antenna. A reader antenna is provided on a periphery of the adapter body.

<CIT> discloses a power cable accessory including an insulation layer. A connector received within the insulation layer and has an RFID tag secured to it wherein the RFID tag comprises a temperature sensor and an antenna. An external RFID reader transmits a signal to the RFID tag to provide power to the RFID tag. The temperature sensor of the RFID tag detects a temperature of the connector, and the antenna transmits a signal to the RFID reader.

According to some embodiments of the present inventive concept, a radio frequency (RF) sensor tag, including a temperature sensor and an antenna, is directly mounted to a connector in a medium or high voltage cable accessory. The RF sensor tag is coupled to an RF reader which is mounted in proximity of the RF sensor tag, but external to the cable accessory. The reader provides wireless power to the tag which accumulates and stores energy in onboard capacitors which may be small. NFC protocol based on NFC standards ISO/IEC <NUM> and ISO/IEC <NUM>-<NUM> enables wireless communication between the sensor tag and reader.

According to one aspect of the inventive concept, a cable connection assembly comprises: an adaptor body; a terminated electrical cable end received within the adaptor body, the electrical cable end terminated by a connector; a radio frequency (RF) sensor tag secured to the connector, the RF sensor tag comprising a temperature sensor and an antenna; and an RF reader externally mounted on the adaptor body, characterized in that the RF reader is configured to transmit an interrogation signal to the RF sensor tag that provides power to the RF sensor tag and causes the temperature sensor to detect a temperature of the connector and generate a temperature data signal, and that causes the antenna to transmit the temperature data signal, and wherein the RF reader is configured to receive the transmitted temperature data signal; and the antenna is a flexible antenna that is secured to and conforms with an outer surface of the connector. The RF reader may be configured to transmit the received temperature data signal to a remote device, such as a smart phone or other computing device. In some embodiments, the RF reader may be configured to display an indication (e.g., one or more colors, etc.) of a temperature of the connector in response to receiving the temperature data signal.

In some embodiments, the outer surface of the connector comprises a recessed portion formed therein, and the temperature sensor is positioned within the recessed portion. The recessed portion acts as a pocket to mechanically protect the temperature sensor and to facilitate insertion of the terminated end of the electrical cable within the adapter body.

In some embodiments, an outer surface of the temperature sensor does not extend above the outer surface of the connector. The antenna may be positioned adjacent the temperature sensor.

In some embodiments, the antenna includes a shield configured to reduce electromagnetic interference from the electrical cable. The shield may include a layer of ferrite, such as a nickel-zinc ferrite or a manganese-zinc ferrite, and a layer of metallic material, such as steel. The layer of metallic material may be adjacent to the outer surface of the connector and the ferrite layer is between the layer of metallic material and the antenna.

In some embodiments, the RF reader is configured to adjust a frequency of the interrogation signal based on a temperature of the connector.

In some embodiments, the RF sensor tag is configured to automatically adjust its operating or resonating frequency in response to a temperature of the connector detected by the temperature sensor.

According to another aspect of the present inventive concept, a method of monitoring a temperature of a connector terminating an end of an electrical cable is provided, wherein the connector is surrounded by an insulative adaptor body, wherein a radio frequency (RF) sensor tag is secured to the connector, the RF sensor tag comprising a temperature sensor and an antenna, the antenna being a flexible antenna that is secured to and conforms with an outer surface of the connector, the method comprising: transmitting an interrogation signal to the RF sensor tag from an RF reader located external to the adaptor body that provides power to the RF sensor tag and causes the temperature sensor to detect a temperature of the connector and generate a temperature data signal, and the antenna to transmit the temperature data signal; and receiving the transmitted data signal at the RF reader. The method may include transmitting the received temperature data signal from the RF reader to a remote device. In some embodiments, the method may include adjusting an operating frequency of the RF sensor tag in response to a temperature of the connector detected by the temperature sensor. In some embodiments, the RF sensor tag may be configured to automatically adjust its operating frequency in response to the temperature of the connector detected by the temperature sensor.

Embodiments of the present inventive concept are advantageous over conventional temperature measurement methods in that temperature data from an electrical cable connector can be wirelessly exported through the thick insulation of a cable accessory to a reader located external to the cable accessory. The temperature data can then be sent to a user who can make a decision whether to repair or replace the connector based on the temperature magnitude, trend, and duration data obtained.

Wireless temperature sensors according to the present inventive concept can directly and accurately measure connector temperatures within medium and high voltage cable accessories. These sensors can provide temperature data that can be used to detect connectors which are in the early stages of overheating. This allows a technician to repair the connector and cable accessory before failure. As such, an electric utility can avoid a catastrophic failure and an unexpected outage which entails costly repairs and loss of power for consumers.

Moreover, the design of the temperature sensor allows RF communication techniques to operate in the presence of high magnetic and electrical fields found within a connector of medium and high voltage electrical cables. The temperature sensing electronics are located within a pocket machined within an outer surface of a connector and a shield of ferrite and steel behind the antenna coil reduces the effect of nearby metals on the antenna.

The low-profile RF sensor tag does not affect the electrical insulation or environmental protection of an electrical cable. The sensor is placed in contact with the element where temperature is measured and is covered by the same electrical insulation the connector would normally have. No wires or cables breach the insulation, which is unimpaired, thereby maintaining the environmental and electrical integrity of the cable connection assembly/cable accessory. This is an important advantage of the present inventive concept over conventional temperature measurement techniques. The present inventive concept allows information to be retrieved from within a cable connection assembly/cable accessory while allowing the cable connection assembly/cable accessory to remain undisturbed. In addition, the readers can be daisy-chained, allowing data to be collected from three (or more) phases simultaneously, thereby allowing the collected data to highlight differences between phases, or trends common to all phases.

These and other objects and/or aspects of the present invention are explained in detail below.

The accompanying drawings, which form a part of the specification, illustrate various embodiments of the present inventive concept. The drawings and description together serve to fully explain embodiments of the present inventive concept.

<FIG> is a cut-away view of an exemplary cable connection assembly <NUM> in which embodiments of the present inventive concept may be implemented. However, embodiments of the present inventive concept may be utilized with many different cable connection assemblies and accessories. Embodiments of the present inventive concept are not limited to the illustrated cable connection assembly <NUM>. The illustrated cable connection assembly <NUM> includes an adapter body <NUM> configured to receive the terminated end of an electrical cable <NUM>. The cable connection assembly <NUM> may be used to terminate and environmentally protect the electrical cable <NUM> and to enable physical and electrical connection between the electrical cable <NUM> and a termination (e.g., a bushing) of associated electrical equipment, such as switchgear, a transformer, etc. The electrical cable <NUM> may be, for example, a medium-voltage (e.g., between about <NUM> and <NUM> kV) or high-voltage (e.g., between about <NUM> and <NUM> kV) power transmission cable.

The illustrated adaptor body <NUM> is formed of a resilient, electrically insulating material, such as, for example, ethylene propylene diene monomer (EPDM) rubber, neoprene or other rubber, and is T-shaped with a tubular main leg <NUM> and a tubular cross leg <NUM>. The main leg <NUM> and cross leg <NUM> define respective intersecting first and second inner passageways 20p, 22p. A metal layer <NUM> is molded into, or otherwise included in, the adaptor body <NUM> and serves as a Faraday cage that reduces electromagnetic interference emanating from the electrical cable <NUM>.

The first passageway 20p is configured to receive the terminated end of the electrical cable <NUM> therein, as illustrated. The end of the electrical cable <NUM> is terminated by a connector <NUM>, such as a cable lug. The second passageway 22p has a frusto-conical configuration and is configured to receive a mating frusto-conical bushing of electrical equipment, such as switchgear, a transformer, etc. The second passageway 22p includes a pin <NUM> that engages the connector <NUM> and that is configured to make electrical contact with the electrical equipment bushing, as would be understood by one skilled in the art. The outermost portion 22a of the cross leg <NUM> is flanged to enhance the mechanical connection onto a bushing of the electrical equipment, as would be understood by one skilled in the art.

<FIG> and <FIG> are schematic illustrations of a cable connection assembly <NUM>, according to some embodiments of the present inventive concept. The cable connection assembly <NUM> includes an adaptor body <NUM>, and a terminated electrical cable end 16e received within the adaptor body <NUM>, as described above with respect to <FIG>. The end 16e of the electrical cable <NUM> is terminated by a connector <NUM>, such as a cable lug. A radio frequency (RF) sensor tag <NUM> is secured to the connector, and the RF sensor tag <NUM> includes a temperature sensor <NUM> and an antenna <NUM> (illustrated in <FIG> and <FIG>). In some embodiments, the RF sensor tag <NUM> may be configured to operate at temperatures up to about <NUM>.

As used herein, RF is used to refer to a broad class of wireless communication interface that can provide communications and power, including far field communication and near field communication (NFC), which may utilize a specific communication protocol. Sensors based on RF technology have beneficial attributes, such as wireless readout, passive (battery-free) sensor operation, unique sensor identification, and onboard micro-processing capabilities. NFC includes but is not limited to the set of standard protocols defined by the NFC Forum industry association.

An RF reader <NUM> is externally mounted on the adaptor body <NUM> and is configured to transmit an interrogation signal to the RF sensor tag <NUM> (<FIG>) that causes the temperature sensor <NUM> to detect a temperature of the connector <NUM> and generate a temperature data signal. The antenna <NUM> is configured to transmit the temperature data signal to the RF reader <NUM>. The RF reader transmits the received temperature data signal to a remote device, such as a smart phone or other computing device, for display and/or storage. In some embodiments, the RF reader <NUM> may be configured to display an indication of a temperature of the connector <NUM> in response to receiving the temperature data signal. For example, as illustrated in <FIG>, a portion 40d of an RF reader <NUM> may be configured to display one or more colors, each color associated with a specific range of temperatures. The RF reader <NUM> may also include a digital display and may be configured to display the temperature of the connector <NUM> directly. However, typically, the RF reader <NUM> will be facing away from a user and toward the equipment that the cable connection assembly <NUM> is attached to.

In some embodiments, the RF reader <NUM> is mounted on an exterior of the adaptor body <NUM> via a strap, bracket or other fastening mechanism <NUM>, as illustrated in <FIG>. A housing <NUM> contains the RF reader circuitry <NUM>, which includes one or more processors and transceivers configured to interrogate a sensor tag and transmit a received data signal to an external device. The RF reader <NUM> is mounted in close proximity to the RF sensor tag <NUM> on the connector <NUM> so that NFC can be established. The RF reader <NUM> provides wireless power to the RF sensor tag <NUM> which accumulates and stores energy in onboard capacitors which may be small. NFC protocol enables wireless communication between the RF sensor tag <NUM> and RF reader <NUM> at <NUM>.

<FIG> illustrates an exemplary connector <NUM> secured to a high voltage electrical cable <NUM>. The illustrated connector <NUM> is a cable lug. The outer surface 24a of the connector <NUM> includes a recessed portion <NUM>. The temperature sensor <NUM> is positioned within the recessed portion <NUM>, as illustrated in <FIG>, and the recessed portion <NUM> acts as a pocket to mechanically protect the temperature sensor <NUM>. The antenna <NUM> is a flexible antenna that is secured to and conforms with the outer surface 24a of the connector <NUM>, as illustrated in <FIG>. The antenna <NUM> is positioned adjacent the temperature sensor <NUM> and is electrically connected to the temperature sensor <NUM>. Embodiments of the present inventive concept are not limited to the illustrated shape and size of the antenna <NUM>. The antenna <NUM> may have various shapes, sizes and configurations without limitation.

In some embodiments, an outer surface 32a of the temperature sensor <NUM> does not extend above the outer surface 24a of the connector. For example, the outer surface 32a of the temperature sensor <NUM> may be recessed within the recessed portion <NUM> or may be substantially flush with the outer surface 24a of the connector <NUM>. This allows the connector <NUM> to be inserted within the adaptor body <NUM> without mechanical interference from the temperature sensor <NUM>. Moreover, due to its flexibility, the antenna <NUM> can be installed on the connector <NUM> in a low-profile format. As such, the recessed portion <NUM> that receives the temperature sensor <NUM> and the flexibility of the antenna <NUM> allows the sensor tag <NUM> to easily fit under existing cable connection assemblies and accessories with no modification required.

In the illustrated embodiment, the recessed portion <NUM> has a generally rectangular shape to match the generally rectangular shape of the temperature sensor <NUM>. However, embodiments of the present inventive concept are not limited to the illustrated shape and size of the temperature sensor <NUM> or the recessed portion <NUM>. Each may have various shapes, sizes and configurations, without limitation.

<FIG> is a schematic illustration of one embodiment of an RF sensor tag <NUM>, according to the present inventive concept. <FIG> is a side view of the sensor tag <NUM> taken along line 5B-5B in <FIG>. The RF sensor tag <NUM> includes a substrate <NUM>, a thermal sensing circuit <NUM> (i.e., temperature sensor) attached to a lower surface 31b of the substrate <NUM> (<FIG>), and an antenna <NUM> on an upper surface 31a of the substrate <NUM> that is electronically coupled to the thermal sensing circuit <NUM>. The substrate <NUM> is flexible such that the sensor tag <NUM> can be attached to and conform with the outer surface 24a of a connector, such as connector <NUM> in <FIG>. In some embodiments, the substrate <NUM> is a flexible polymeric film, such as KAPTON® film, available from E. duPont de Nemours and company, Wilmington, Delaware.

Referring to <FIG>, the antenna <NUM> and thermal sensor <NUM> of the RF sensor tag <NUM> are illustrated in greater detail. The copper coil 34a of the antenna is attached to the flexible substrate <NUM>. The antenna <NUM> also includes a shield <NUM> below the flexible substrate <NUM> that is positioned between the antenna <NUM> and the connector <NUM>. The shield <NUM> is configured to reduce electromagnetic interference from the connector <NUM>. The illustrated shield <NUM> includes a layer of ferrite 36a, such as, for example, a nickel-zinc ferrite or a manganese-zinc ferrite, and a layer of metallic material 36b, such as, for example, steel or other material with suitably high magnetic permeability. The metallic material layer 36b serves as a "shield" to the ferrite layer 36a to prevent the ferrite layer 36a from becoming saturated. The ferrite layer 36a isolates the antenna coil 34a from the magnetic surface of the connector <NUM>. The ferrite layer 36a and metallic layer 36b are joined by a layer of double sided tape 36c, and another layer of double sided tape 36d is adhesively secured to the metallic layer 36b and adheres the antenna <NUM> to the connector <NUM>.

In some embodiments, a combined thickness of the antenna <NUM> and shield <NUM> may be about <NUM>. The flexible film <NUM> upon which the copper coil 34a is secured may have a thickness of about <NUM>. The ferrite layer 36a may have a thickness of about <NUM> - <NUM>, and the metallic layer 36b may have a thickness of about <NUM>. The double sided tape layers 36c, 36d may have a thickness of about <NUM>. However, the various layers may have different thicknesses and embodiments of the present invention are not limited to a particular thickness for any of the layers of the antenna <NUM> and shield <NUM>.

Still referring to <FIG>, the thermal sensor <NUM> is illustrated positioned within the recessed portion <NUM> of the connector <NUM>. In the embodiment of <FIG>, the upper surface 32a of the thermal sensor <NUM> extends above the outer surface 24a of the connector <NUM>. However, it is understood that the upper surface 32a of the thermal sensor may be substantially flush with or recessed from the outer surface 24a of the connector <NUM> in other embodiments. In some embodiments, a combined thickness of the thermal sensor <NUM> may be about <NUM>. The illustrated thermal sensor <NUM> includes a circuit board <NUM> that contains thermal detecting circuitry. A thermal pad <NUM> is positioned between the circuit board <NUM> and the connector <NUM> in the recessed portion <NUM>. The thermal pad <NUM> ensures good thermal conductivity between the connector <NUM> and the circuit board <NUM>. The thermal pad <NUM> helps the thermal detecting circuitry on the circuit board <NUM> track the temperature of the connector as closely as possible. A pin header <NUM> connects the flexible substrate <NUM> to the less flexible circuit board <NUM>; however, another type of connector could be utilized, also. A capacitor <NUM> is used to store the energy harvested from the RF field. This energy enables the sensor tag <NUM> to operate. In some embodiments, the circuit board <NUM> has a thickness of about <NUM> and the thermal pad <NUM> has a thickness of about <NUM>. However, the circuit board <NUM> and the thermal pad <NUM> may have different thicknesses and embodiments of the present invention are not limited to a particular thickness for either.

The RF reader <NUM> may be configured to adjust a frequency of the interrogation signal based on a temperature of the connector <NUM>. For example, the RF reader <NUM> may "tune" the resonant frequency of the RF sensor tag <NUM> for an upper end of a normal expected operating temperature range, rather than ambient temperature.

The RF sensor tag <NUM> may also be configured to automatically adjust its operating frequency in response to a temperature of the connector detected by the temperature sensor <NUM>. The sensor tag <NUM> includes a microprocessor, which may be small, to perform this function.

Referring to <FIG> and <FIG>, multiple RF readers <NUM> can be daisy-chained, allowing data to be collected from three (or more) phases simultaneously, thereby allowing the collected data to highlight differences between phases, or trends common to all phases.

Claim 1:
A cable connection assembly (<NUM>) comprising:
an adaptor body (<NUM>);
a terminated electrical cable end (16e) received within the adaptor body (<NUM>), the electrical cable end (16e) terminated by a connector (<NUM>);
a radio frequency (RF) sensor tag (<NUM>) secured to the connector (<NUM>), the RF sensor tag (<NUM>) comprising a temperature sensor (<NUM>) and an antenna (<NUM>); and
an RF reader (<NUM>) externally mounted on the adaptor body (<NUM>),
wherein
the RF reader (<NUM>) is configured to transmit an interrogation signal to the RF sensor tag (<NUM>) that provides power to the RF sensor tag (<NUM>) and causes the temperature sensor (<NUM>) to detect a temperature of the connector (<NUM>) and generate a temperature data signal, and that causes the antenna (<NUM>) to transmit the temperature data signal, and wherein the RF reader (<NUM>) is configured to receive the transmitted temperature data signal; characterised in that
the antenna (<NUM>) is a flexible antenna that is secured to and conforms with an outer surface (24a) of the connector (<NUM>).