WO2021212292A1

WO2021212292A1 - Wireless sensing apparatus on bushing

Info

Publication number: WO2021212292A1
Application number: PCT/CN2020/085738
Authority: WO
Inventors: Yibo Zhang; Delun MENG; Baokun XU
Original assignee: Abb Schweiz Ag
Priority date: 2020-04-20
Filing date: 2020-04-20
Publication date: 2021-10-28

Abstract

Embodiments of present disclosure relate to a wireless sensing apparatus on bushing. The apparatus comprises: a current sensor (102) arranged on an end surface (400) of a bushing (110) at which a cable accessory (300) is coupled to the bushing (110), and configured to generate a current signal representing a current flowing through a bushing conductor (120) in the bushing (110); a magnetic loop (106) arranged on the end surface (400) of the bushing (110) and surrounding the bushing conductor (120), the magnetic loop (106) configured to generate a magnetic signal based on the current so that the current sensor (102) generates the current signal based on the magnetic signal; and a communication unit (104) arranged on the end surface (400) of the bushing (110), and configured to transmit the current signal to an external device.

Description

WIRELESS SENSING APPARATUS ON BUSHING

FIELD

Embodiments of the present disclosure generally relates to a wireless sensing apparatus on bushing, and particularly to a wireless sensing apparatus for monitoring a parameter for a bushing conductor.

BACKGROUND

With increasing demands for electrical power, switchgears are widely utilized in electrical power systems. In order to ensure normal functions of the switchgears to guarantee safeties of the electrical power systems, it is desirable to monitor operating parameters of the switchgear. Digitalization is a trend in monitoring of the switchgear, and there are increasing demands for digital solutions of remote monitoring unit (RMU) to develop smart applications in power distribution systems.

On one hand, a temperature is a key parameter to be monitored for electrical connection in the electrical power system, because a failure mainly results from heat generation in the electrical connection. To prevent and reduce the failure caused by the heat generation, a temperature sensor is provided for a cable connection in the switchgear to monitor the temperature of the cable connection. On the other hand, a current flowing through the cable connection is another key parameter to be monitored during an operation of the switchgear. The current may be used to indicate the load status of the switchgear, and the load status may be used to predict the temperature range in normal connection condition.

Several wireless sensing solutions have been proposed to monitor the cable connection in the switchgear. However, some of such solutions require placements of sensors in such a manner that causes changes in structures of bushing or cable accessory for the cable connection. Some other solutions require specific structures of the bushing or the cable accessory to mount the sensors, and thus are not suitable for most commonly used bushings and cable accessories.

It is desirable to provide an improved solution for wirelessly sensing the parameters for the cable connection in the switchgear, which can be easily implemented without altering the existing structures of the bushing and the cable accessory.

SUMMARY

Embodiments of the present disclosure provide a wireless sensing apparatus on bushing, which can be easily arranged to monitor the parameter for the bushing conductor without changing the structures of the bushing and the cable accessory.

In a first aspect, embodiments of the present disclosure provide an apparatus. The apparatus comprises: a current sensor arranged on an end surface of a bushing at which a cable accessory is coupled to the bushing, and configured to generate a current signal representing a current flowing through a bushing conductor in the bushing; a magnetic loop arranged on the end surface of the bushing and surrounding the bushing conductor, the magnetic loop configured to generate a magnetic signal based on the current so that the current sensor generates the current signal based on the magnetic signal; and a communication unit arranged on the end surface of the bushing, and configured to transmit the current signal to an external device.

Compared with conventional wireless sensing solutions, the apparatus according to the embodiment of the present disclosure may be arranged on the end surface of the bushing to monitor the current for the bushing conductor. The apparatus may be easily implemented without altering the existing structures of the bushing and the cable accessory, and may be suitable for the commonly used bushing and cable accessory.

In some embodiments, the apparatus further comprises: a temperature sensor arranged on the end surface of the bushing and configured to sense a temperature of the bushing conductor in the bushing and to generate a sensor signal representing the sensed temperature.

In some embodiments, the temperature sensor is arranged to be in thermal contact with a protruding portion of the bushing conductor from the end surface of the bushing.

In some embodiments, the communication unit is further configured to transmit the sensor signal to the external device.

In some embodiments, the apparatus further comprises: an antenna arranged on the end surface of the bushing separately from the communication unit, and configured to transmit the sensor signal to the external device.

In some embodiments, the magnetic loop is arranged to surround a protruding portion of the bushing conductor from the end surface of the bushing.

In some embodiments, the apparatus further comprises a power management unit configured to supply power to the current sensor, the power management unit is powered by the magnetic loop or by an external power source.

In some embodiments, the communication unit comprises a transceiver antenna, and an inner diameter of the transceiver antenna is equal to or greater than an outer diameter of the bushing conductor, and an outer diameter of the transceiver antenna is equal to or less than a diameter of the end surface of the bushing.

In some embodiments, an inner diameter of the antenna is equal to or greater than an outer diameter of the bushing conductor, and an outer diameter of the antenna is equal to or less than a diameter of the end surface of the bushing.

In some embodiments, the antenna has a C-like or fan shape.

In some embodiments, the current sensor and the communication unit are attached onto the end surface of the bushing by glue or clamp.

In some embodiments, the temperature sensor and the antenna are attached onto the end surface of the bushing by glue or clamp.

In some embodiments, the communication unit comprises a transceiver antenna configured to transmit the current signal based on radio frequency identification.

In some embodiments, the antenna is configured to transmit the sensor signal based on the radio frequency identification.

In some embodiments, the external device comprises a reader arranged in a switchgear and configured to receive the current signal via a reader antenna arranged in the switchgear.

In a second aspect, embodiments of the present disclosure provide an apparatus. The apparatus comprises: a temperature sensor arranged on an end surface of a bushing at which a cable accessory is coupled to the bushing, and configured to sense a temperature of a bushing conductor in the bushing and to generate a sensor signal representing the sensed temperature; and an antenna of a C-like or fan shape, the antenna arranged on the end surface of the bushing and configured to transmit the sensor signal to an external device.

Compared with conventional wireless sensing solutions, the apparatus according to the embodiment of the present disclosure may be arranged on the end surface of the bushing to monitor the temperature for the bushing conductor. The apparatus may be easily implemented without altering the existing structures of the bushing and the cable accessory, and may be suitable for the commonly used bushing and cable accessory. Moreover, the apparatus has a higher reliability than that having an antenna of a ring shape, because the antenna of the C-like or the fan-shape may not be adversely affected by a thermal stress resulting from heat generation.

In some embodiments, the apparatus further comprises: a redundancy temperature sensor arranged on the end surface of the bushing, and configured to sense the temperature of the bushing conductor in the bushing and to generate a further sensor signal representing the sensed temperature; and a redundancy antenna arranged on the end surface of the bushing separately from the antenna, and configured to transmit the further sensor signal to the external device.

In some embodiments, the apparatus further comprises: a current sensor arranged on the end surface of the bushing, and configured to generate a current signal representing a current flowing through the bushing conductor in the bushing.

In some embodiments, the apparatus further comprises: a communication unit arranged on the end surface of the bushing separately from the antenna, and configured to transmit the current signal to the external device.

In some embodiments, the antenna is further configured to transmit the current signal to the external device.

In some embodiments, a radian of the C-like or the fan-shape ranges from 20°to 360°.

In some embodiments, the radian is 180°.

In some embodiments, the temperature sensor comprises at least one of a thermocouple, a thermistor, a negative temperature coefficient element, a molybdenum electrical, and a semiconductor device.

In some embodiments, the apparatus further comprises a power management unit configured to supply power to the temperature sensor (202) , the power management unit is powered by energy harvesting by a radio frequency wave or by an external power source.

In some embodiments, the antenna is configured to transmit the sensor signal based on radio frequency identification, and the communication unit comprises a transceiver antenna configured to transmit the current signal based on the radio frequency identification.

In some embodiments, the external device comprises a reader arranged in a switchgear and configured to receive the sensor signal via a reader antenna arranged in the switchgear.

In a third aspect, embodiments of the present disclosure provide an Internet of Things (IoT) system. The IoT system comprises a wireless sensing apparatus comprising the apparatus as described above.

According to embodiments of the present disclosure, the apparatus for monitoring the temperature and/or the current can be easily implemented by arranging components of the apparatus on the end surface of the bushing. The apparatus on the bushing is suitable for the commonly used bushing and cable accessory without changing the existing structures.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are shown and illustrated with reference to the drawings. The drawings serve to illustrate the basic principle, so that only aspects necessary for understanding the basic principle are illustrated. The drawings are not to scale. In the drawings the same reference characters denote like features. For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

Fig. 1 illustrates a block diagram of an apparatus for sensing a parameter of a bushing conductor in a bushing according to an embodiment of the present disclosure;

Fig. 2 illustrates a block diagram of an apparatus for sensing another parameter of a bushing conductor in a bushing according to an embodiment of the present disclosure;

Fig. 3 illustrates a schematic diagram of a bushing and a cable accessory according to an embodiment of the present disclosure;

Figs. 4A-4C illustrate schematic views of a bushing and a bushing conductor according to embodiments of the present disclosure;

Figs. 5A-5C illustrate arrangements of an apparatus on an end surface according to embodiments of the present disclosure;

Figs. 6A-6C illustrate arrangements of an apparatus on an end surface according to embodiments of the present disclosure;

Figs. 7A-7B illustrate other arrangements of an apparatus on an end surface according to embodiments of the present disclosure;

Fig. 8 illustrates a block diagram of an example implementation of the apparatus according to an embodiment of the present disclosure;

Fig. 9 illustrates a block diagram of an example implementation of the apparatus according to an embodiment of the present disclosure; and

Fig. 10 illustrates a block diagram of an Internet of Things system according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

The subject matter described herein will now be discussed with reference to several example embodiments. These embodiments are discussed only for the purpose of enabling those skilled persons in the art to better understand and thus implement the subject matter described herein, rather than suggesting any limitations on the scope of the subject matter.

The term “comprises” or “includes” and its variants are to be read as open terms that mean “includes, but is not limited to. ” The term “or” is to be read as “and/or” unless the context clearly indicates otherwise. The term “based on” is to be read as “based at least in part on. ” The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment. ” The term “another embodiment” is to be read as “at least one other embodiment. ” Unless specified or limited otherwise, the terms “mounted, ” “connected, ” “supported, ” and “coupled” and variations thereof are used broadly and encompass direct and indirect mountings, connections, supports, and couplings. Furthermore, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. In the description below, like reference numerals and labels are used to describe the same, similar or corresponding parts in the Figures. Other explicit and implicit definitions may be included below.

In a conventional solution, sensors are pre-installed and capsulated in a ring member and then the ring is mounted into a groove of a bushing. In this case, the structure of the bushing needs to be changed to have the groove therein. In another solution, a thermal sensor is integrated into a sleeve to monitor a temperature of a cable head. In this case, the sensor is casted into epoxy of the bushing, and thus the sensor cannot be replaced if it is out of service. In other solution as disclosed in CN107257009A, there is no change made to the busing or the cable accessory. However, a sensor with ring shape disclosed in CN107257009A can only be installed inside a specific insulating bushing plug, which is not suitable for most commonly used cable accessories. Furthermore, in some conventional solutions, the temperature sensor should be installed during onsite installation, and the temperature measurement function might be influenced due to improper installation.

In view of the above, embodiments of the present disclosure provide an improved solution for sensing the bushing conductor in the bushing, which is simple to install, easy to replace and there is no change to the bushing and the cable accessory. In some embodiments, a current sensor, a magnetic loop and a communication unit are arranged on an end surface of the bushing to monitor a current flowing through the bushing conductor. In some embodiments, a temperature sensor and an antenna of a C-like or fan shape are arranged on an end surface of the bushing to monitor a temperature of the bushing conductor. In some embodiments, the current sensor and the temperature sensor are arranged on the end surface of the bushing to dynamically monitor the current and the temperature. The solutions do not depend on the specific bushing and cable accessory, and can be suitable for most popular suppliers of cable accessories without changing existing structures. The apparatus can be installed in the factory to avoid the negative influence that may occur during onsite installation.

Hereinafter, some example embodiments of the present disclosure will be described for purpose of illustration.

Fig. 1 illustrates a block diagram of an apparatus 100 for sensing current of a bushing conductor 120 in a bushing 110 according to an embodiment of the present disclosure. The apparatus 100 comprises a current sensor 102, a magnetic loop 106 and a communication unit 104.

The current sensor 102 is arranged on the end surface of the bushing 110. At the end surface side, the bushing 110 is coupled to a cable accessory. The current sensor 102 is configured to generate a current signal representing the current flowing through the bushing conductor 120. The bushing conductor 120 is provided within the bushing 110. In some embodiments, a portion of the bushing conductor 120 protrudes from the end surface of the bushing 110. In some embodiments, the current sensor 102 may comprise a sensing integrated circuit. In some embodiments, the current sensor 102 may comprise a signal processing circuit and a storage circuit.

The magnetic loop 106 is arranged on the end surface of the bushing 110. The magnetic loop 106 surrounds the bushing conductor 120. In some embodiments, the magnetic loop 106 surrounds a protruding portion of the bushing conductor 120 from the end surface of the bushing 110. In some embodiments, the magnetic loop 106 is arranged in proximity of the protruding portion of the busing conductor 120. The magnetic loop 106 is configured to generate a magnetic signal based on the current, so that the current sensor 102 generates the current signal representing the current in the bushing conductor 120 based on the magnetic signal. The principle of sensing the current is well known in the art, and the descriptions thereof will be omitted herein.

The communication unit 104 is arranged on the end surface of the bushing 110. The communication unit 104 is electrically coupled to the current sensor 102. The communication unit 104 is configured to transmit the current signal to an external device. In addition, the communication 104 may receive a signal transmitted from the external device. The communication unit 104 may communicate with the external device in any known wireless manner.

In some embodiments, the communication unit 104 may comprise a transceiver antenna that is configured to transmit the current signal based on radio frequency identification (RFID) . In some embodiments, the current sensor 102 comprises a radio frequency interface that is configured to interface with the antenna.

According to embodiments of the present disclosure, the apparatus 100 is arranged on the end surface of the bushing 110 to monitor the current flowing through the bushing conductor 120. In this way, a wireless sensing for the current may be easily implemented on the end surface of the bushing without altering the structures of the bushing and the cable accessory coupled to the bushing.

Fig. 2 illustrates a block diagram of an apparatus 200 for sensing temperature of the bushing conductor 120 in the bushing 110 according to an embodiment of the present disclosure. The apparatus 200 comprises a temperature sensor 202 and an antenna 204.

The temperature sensor 202 is arranged on the end surface of the bushing 110 at which the cable accessory is coupled to the bushing 110. The temperature sensor 202 is configured to sense the temperature of the bushing conductor 120 in the bushing 110. The temperature sensor 202 is configured to generate a sensor signal representing the sensed temperature. In some embodiments, the temperature sensor 202 is arranged to be in thermal contact with the protruding portion of the bushing conductor 120 for the end surface of the bushing 110. In some embodiments, the temperature sensor 202 comprises at least one of a thermocouple, a thermistor, a negative temperature coefficient (NTC) element, a molybdenum electrical, and a semiconductor device.

The antenna 204 has a C-like or fan shape and is arranged on the end surface of the bushing 110. The antenna 204 is electrically coupled to the temperature sensor 202. The antenna 204 is configured to transmit the sensor signal to the external device. In addition, the antenna 204 may receive a signal transmitted from the external device. In some embodiments, the antenna 204 is configured to transmit the current signal based on radio frequency identification (RFID) . In some embodiments, the temperature sensor 202 comprises a radio frequency interface that is configured to interface with the antenna 204.

According to the embodiments of the present disclosure, the apparatus 200 is arranged on the end surface of the bushing 110 to monitor the temperature of the bushing conductor 120. In this way, a wireless sensing for the temperature may be easily implemented on the end surface of the bushing without altering the structures of the bushing and the cable accessory coupled to the bushing. Moreover, compared with an antenna having a ring shape, the antenna 204 of the C-like or the fan shape may not be adversely affected by the thermal stress due to the heat generation. Thus, the antenna 204 may be prevented from cracking or being split off from the end surface, thereby improving the reliability of the apparatus 200.

It is to be understood that the

apparatuses

100 and 200 can be combined. For example, in some embodiments, the apparatus 100 as illustrated in Fig. 1 may further comprise the temperature sensor 202 of the apparatus 200. The current sensor 102 and the temperature sensor 202 can be both arranged on the end surface of the bushing 110. The apparatus 100 may provide the current signal representing the current flowing through the bushing conductor 120 as well as the sensor signal representing the temperature of the bushing conductor 120.

In some embodiments, the communication unit 104 of the apparatus 100 is electrically coupled to the temperature sensor 202, to transmit the sensor signal to the external device. The apparatus 100 may transmit the current signal and the sensor signal to the external device via the communication unit 104. Alternatively, in other embodiments, the apparatus 100 further comprises the antenna 204 of Fig. 2. The apparatus 100 comprises the communication unit 104 and the antenna 204 both arranged on the end surface of the bushing 110. The apparatus 100 may transmit the current signal and the sensor signal to the external device via the communication unit 104 and the antenna 204, respectively. In this way, the cable connection may be dynamically monitored by sensing both the current and the temperature.

The apparatus 200 may comprise one or more components of the apparatus 100. For example, in some embodiments, the apparatus 200 may further comprise the current sensor 102 of the apparatus 100. The temperature sensor 202 and the current sensor 102 can be both arranged on the end surface of the bushing 110. The apparatus 200 may provide the sensor signal representing the temperature of the bushing conductor 120 as well as the current signal representing the current flowing through the bushing conductor 120.

In some embodiments, the apparatus 200 further comprises the magnetic loop 106 of Fig. 1. In some embodiments, the antenna 204 of the apparatus 200 is electrically coupled to the current sensor 102, to transmit the current signal to the external device. The apparatus 200 may transmit the sensor signal and the current signal to the external device via the antenna 204. Alternatively, in other embodiments, the apparatus 200 further comprises the communication unit 104 of Fig. 1. The apparatus 200 comprises the antenna 204 and the communication unit 104 both arranged on the end surface of the bushing 110. The apparatus 200 may transmit the sensor signal and the current signal to the external device via the antenna 204 and the communication unit 104, respectively. In this way, the cable connection may be dynamically monitored by sensing both the temperature and the current.

In some embodiments, the external device comprises a reader arranged in the switchgear. The reader is configured to receive the current signal representing the current and/or the sensor signal representing the temperature via a reader antenna. The reader antenna is arranged in the switchgear. The reader and the reader antenna are arranged in different compartments of the switchgear.

Fig. 3 illustrates a schematic diagram of the bushing 110 and the cable accessory 300 according to an embodiment of the present disclosure. As shown in Fig. 3, the bushing conductor 120 is provided within the bushing 110, and a cable lug 302 is provided within the cable accessory 300. The cable lug 302 is mechanically coupled to a bolt 304, and the bolt 304 is mechanically coupled to the bushing conductor 120. The bushing conductor 120 is electrically coupled to the cable lug 302.

Referring to Fig. 3, the bushing 100 has the end surface, and the bushing conductor 120 protrudes from the end surface to be coupled to the cable lug 302. The bushing 110 is coupled to the cable accessory 300 at the end surface via the bushing conductor 120 and the cable lug 302. At the end surface side, the bushing 110 is coupled to the cable accessory 300. At a side of the bushing 110 opposite to the end surface side, the bushing conductor 120 receives the current from an external source.

As described above, the

apparatus

100 or 200 is arranged on the end surface of the bushing 110. In other words, the apparatus 100 or the apparatus 200 is arranged between the end surface of the bushing 110 and the cable lug 302. More specifically, the

apparatus

100 or 200 is arranged in a gap between the end surface of the bushing 110 and the cable lug 302. In this way, the temperature and/or the current for the bushing conductor 120 may be sensed and monitored without changing existing structures of the bushing 110 and the cable accessory 300. Moreover, components of the

apparatus

100 or 200 may be easily replaced, which facilitates the maintenance of the

apparatus

100 or 200. Furthermore, the

apparatus

100 or 200 is suitable for the commonly used bushing and cable accessory, and may be installed during assembly of the cable connection.

Figs. 4A-4C illustrate schematic views of the bushing 110 and the bushing conductor 120 according to embodiments of the present disclosure.

Fig. 4A illustrates a cross-sectional diagram of the bushing 110 and the bushing conductor 120. The bushing conductor 120 protrudes from the end surface 400 of the bushing 110 by a height H. The bushing 110 is the commonly used bushing in the art. For example, the height H may range from 1 to 1.5 mm according to the standard of EN50181. In some embodiments, for the commonly used bushing and bushing conductor, a thickness for the component of the

apparatus

100 or 200 may be lower than 1.5 mm.

Fig. 4B illustrates a perspective view of the bushing 110 and the bushing conductor 120. Fig. 4B shows the end surface 400 of the bushing 110 on which the

apparatus

100 or 200 is to be arranged.

Fig. 4C illustrates a side view of the bushing 110 and the bushing conductor 120. Fig. 4C shows that the end surface 400 has a ring shape and surrounds the bushing conductor 120. In some embodiments, the

apparatus

100 or 200 is arranged on the end surface 400 as shown in Fig. 4C to sense the parameter of the bushing conductor 120.

Figs. 5A-5C illustrate arrangements of the apparatus 100 on the end surface 400 according to embodiments of the present disclosure.

Referring to Fig. 5A, the apparatus 100 comprises the current sensor 102 and the magnetic loop 106 arranged on the end surface 400 of the bushing 110. The magnetic loop 106 is arranged in proximity of the bushing conductor 120 to surround the bushing conductor 120. In some embodiments, the magnetic loop 106 surrounds the protruding portion of the bushing conductor 120 from the end surface 400 of the bushing 110. Moreover, the communication unit 104 of the apparatus 100 comprises a transceiver antenna 502 arranged on the end surface 400 of the bushing 110. In the embodiment as shown in Fig. 5A, the transceiver antenna 502 has a ring shape and surrounds the bushing conductor 120. In some embodiments, the current sensor 102 is disposed on the transceiver antenna 502. In some embodiments, the transceiver antenna 502 transmits the current signal based on RFID to the external device.

Referring to Fig. 5B, the apparatus 100 may further comprise the temperature sensor 202 arranged on the end surface 400 of the bushing 110. The temperature sensor 202 is arranged to be in thermal contact with the bushing conductor 120. In some embodiments, the temperature sensor 202 is disposed on the transceiver antenna 502. The transceiver antenna 502 transmits the sensor signal generated by the temperature sensor 202 to the external device.

Referring to Fig. 5C, the apparatus 100 may further comprise an antenna 504. In this embodiment, the antenna 204 is embodied in the antenna 504 with C-like or fan shape, and the transceiver antenna 502 has a C-like or a fan-shape. The antenna 504 is disposed on the end surface 400 of the bushing 110 and is separated from the transceiver antenna 502. In some embodiments, the temperature sensor 202 is disposed on the antenna 504. The antenna 504 transmits the sensor signal generated by the temperature sensor 202 to the external device. In some embodiments, the antenna 504 transmits the sensor signal based on RFID.

In the embodiments as shown in Figs. 5A-5C, an inner diameter of the transceiver antenna 502 may be equal to or greater than an outer diameter of the bushing conductor 120, and an outer diameter of the transceiver antenna 502 may be equal to or less than a diameter of the end surface 400 of the bushing 110. Moreover, an inner diameter of the antenna 504 may be equal to or greater than the outer diameter of the bushing conductor 120, and an outer diameter of the antenna 504 may be equal to or less than the diameter of the end surface 400 of the bushing 110.

Furthermore, the current sensor 102 and the communication unit 104 may be packaged or assembled. In some embodiments, the current sensor 102 and the transceiver antenna 502 are packaged with PET or PI material or mounted on a printed circuit board. In some embodiments, the current sensor 102 and the transceiver antenna 104 are attached onto the end surface 400 of the bushing 110 by glue or clamp.

The temperature sensor 202 and the antenna 204 may be similarly packaged or assembled. In some embodiments, the temperature sensor 202 and the antenna 504 are packaged with PET or PI material or mounted on a printed circuit board. In some embodiments, the temperature sensor 202 and the antenna 504 are attached onto the end surface 400 of the bushing 110 by glue or clamp.

It should be noted that the shape of the transceiver antenna 502 or the antenna 504 is not limited to Figs. 5A-5C. In other embodiments, the transceiver antenna 502 or the antenna 504 may have any other suitable shape.

Figs. 6A-6C illustrate arrangements of the apparatus 200 on the end surface 400 according to embodiments of the present disclosure.

Referring to Fig. 6A, the apparatus 200 comprises the temperature sensor 202 and an antenna 602 arranged on the end surface 400 of the bushing 110. In this embodiment, the antenna 204 is embodied in the antenna 602 with the C-like or the fan shape. The temperature sensor 202 is arranged to be in thermal contact with the protruding portion of the bushing conductor 120 from the end surface 400 of the bushing 110. In some embodiments, the temperature sensor 202 is arranged to contact a sidewall of the protruding portion of the bushing conductor 120. In some embodiments, the temperature sensor 202 is disposed on the antenna 602.

Referring to Fig. 6B, the antenna 602 has the C-like or fan shape with a different radian. By way of example, in some embodiments, the radian of the C-like or the fan-shape ranges from 20° to 360°. In some embodiments, the radian may 180°. Any other suitable numerals are possible in other embodiments.

The antenna of the C-like or the fan-shape has a higher reliability than an antenna of a ring-shape. The antenna arranged in proximity of the bushing conductor 120 is influenced by heat generated from the bushing conductor 120 as the current flows through the bushing conductor 120. Thus, the antenna suffers from the thermal stress resulting from the heat. The antenna of the closed ring-shape may crack or may be split off from the end surface under the thermal stress, resulting in degradation or failure of the antenna. However, the antenna of the C-like or the fan-shape may not be adversely affected during thermal expansion and contraction due to the heat, because it has a greater margin by a non-closed shape to withstand the thermal expansion and contraction.

Further, the antenna of the C-like or the fan-shape allows redundancy components to be arranged on the end surface 400 of the bushing 110. In this way, the redundancy components for sensing the parameter may be enabled when the temperature sensor 202 or the antenna 602 is out of service. Therefore, the safety of the cable connection may be ensured and the maintenance of the apparatus may be improved.

Referring to Fig. 6C, the apparatus 200 may further comprise a redundancy temperature sensor 604 and a redundancy antenna 606 arranged on the end surface 400 of the bushing 110. The redundancy temperature sensor 604 is configured to sense the temperature of the bushing conductor 120 and generates a further sensor signal representing the sensed temperature. The redundancy antenna 606 is arranged separately from the antenna 604, and the redundancy antenna 606 is configured to transmit the further sensor signal to the external device. The redundancy temperature sensor 604 and the redundancy antenna 606 may be configured in a similar way to the temperature sensor 202 and the antenna 602.

In some embodiments, the apparatus 200 may further comprise the current sensor 102, the magnetic loop 106 and the antenna 502 as described with reference to Fig. 5C, for sensing the current for the bushing conductor 120 in addition to the temperature.

In the embodiments as shown in Figs. 6A-6C, an inner diameter of the antenna 602 may be equal to or greater than the outer diameter of the bushing conductor 120, and an outer diameter of the antenna 602 may be equal to or less than the diameter of the end surface 400 of the bushing 110.

Furthermore, the temperature sensor 202 and the antenna 204 may be packaged or assembled. In some embodiments, the temperature sensor 202 and the antenna 602 are packaged with PET or PI material or mounted on a printed circuit board. In some embodiments, the temperature sensor 202 and the antenna 602 are attached onto the end surface 400 of the bushing 110 by glue or clamp.

It should be noted that the shape of the antenna 602 is not limited to Figs. 6A-6C. In other embodiments, the antenna 602 may have any other suitable shape.

Figs. 7A-7B illustrate other arrangements on the end surface 400 according to embodiments of the present disclosure.

Referring to Fig. 7A, the apparatus for sensing the temperature comprises the temperature sensor 202 and an antenna 702 of a rectangular shape arranged on the end surface 400 of the bushing 110. The antenna 702 transmits the sensor signal generated by the temperature sensor 202 to the external device. Moreover, the apparatus for sensing the current may also comprise a transceiver antenna having the rectangular shape as shown in Fig. 7A.

Referring to Fig. 7B, the apparatus for sensing the temperature as well as the current comprises the temperature sensor 202, the current sensor 102 and the magnetic loop 106 arranged on the end surface 400 of the bushing 110. The apparatus further comprises an antenna 702 and an antenna 704. In this embodiment, the communication unit 104 of the apparatus 100 is embodied in the antenna 704, and the antenna 204 of the apparatus 100 is embodied in the antenna 702. The sensor signal and the current signal are transmitted to the external device via the antenna 702 and the antenna 704, respectively.

Fig. 8 illustrates a block diagram of an example implementation of the apparatus 100 according to an embodiment of the present disclosure. Referring to Fig. 8, the apparatus 100 may further comprise a power management unit 802 that is configured to supply power to the current sensor 102. In some embodiments, the magnetic loop 106 is further configured to generate a voltage, and the power management unit 802 is powered by the voltage. In this way, there is no need for an external power source. In other embodiments, the power management unit 802 is powered by an external power source such as a current transformer, and supplies the power to the current sensor 102 from the current transformer.

Fig. 9 illustrates a block diagram of an example implementation of the apparatus 200 according to an embodiment of the present disclosure. Referring to Fig. 9, the apparatus 200 may further comprise a power management unit 902 that is configured to supply power to the temperature sensor 202. In some embodiments, the power management unit 902 is powered by energy harvesting by a radio frequency wave, to supply the power to the temperature sensor 202. In these embodiments, the temperature sensor 202 is embodied in a passive wireless sensor. In this way, there is no need for an external power source. In other embodiments, the power management unit 902 is power by the external power source such as the current transformer.

Fig. 10 illustrates a block diagram of an Internet of Things (IoT) system 1000 according to an embodiment of the present disclosure. As shown in Fig. 10, the IoT system 1000 includes a wireless sensing apparatus 1002 comprising the

apparatus

100 or 200. In the IoT system 1000, the wireless sensing apparatus 1002 is coupled to a control system 1004 of the IoT system 1000 via a wired or wireless communication. In some embodiments, more than one wireless sensing apparatus 1002 may be included in the IoT system 1000 and coupled to the control system 1004. In some embodiments, more than one bushing 110 may be included in the IoT system 1000 and coupled to the control system 1004 via a wired or wireless communication.

In some embodiments, the control system 1004 may be configured to monitor the operating parameters for the bushing conductor in the bushing 110 sensed by the wireless sensing apparatus 1002. In some embodiments, the control system 1004 may be further configured to control operations of the wireless sensing apparatus 1002, and/or operations of the bushing conductor in the bushing 110.

According to the embodiments of the present disclosure, the temperature and/or the current for the bushing conductor may be monitored by arranging the

apparatus

100 or 200 on the end surface of the bushing. Such arrangement does not depend on the specific structures of the bushing and the cable accessory, and can be easily implemented without altering the structures of the bushing and the cable accessory. Therefore, the operating parameters for the cable connection may be dynamically monitored by a more feasible and reliable wireless sensing solution.

While several details are contained in the above discussions, these should not be construed as limitations on the scope of the subject matter described herein, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. On the other hand, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the subject matter has been described in language specific to structural features, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features described above. Rather, the specific features described above are disclosed as example forms of implementing the claims. In light of this, the scope of the present disclosure should not be limited to that of the particular embodiments illustrated and described herein, as they are merely by way of some examples thereof, but rather, should be fully commensurate with that of the claims appended hereafter and their functional equivalents.

Claims

An apparatus (100) comprising:

a current sensor (102) arranged on an end surface (400) of a bushing (110) at which a cable accessory (300) is coupled to the bushing (110) , and configured to generate a current signal representing a current flowing through a bushing conductor (120) in the bushing (110) ;

a magnetic loop (106) arranged on the end surface (400) of the bushing (110) and surrounding the bushing conductor (120) , the magnetic loop (106) configured to generate a magnetic signal based on the current so that the current sensor (102) generates the current signal based on the magnetic signal; and

a communication unit (104) arranged on the end surface (400) of the bushing (110) , and configured to transmit the current signal to an external device.
The apparatus (100) of claim 1, further comprising:

a temperature sensor (202) arranged on the end surface (400) of the bushing (110) and configured to sense a temperature of the bushing conductor (120) in the bushing (110) and to generate a sensor signal representing the sensed temperature.
The apparatus (100) of claim 2, wherein the temperature sensor (202) is arranged to be in thermal contact with a protruding portion of the bushing conductor (120) from the end surface (400) of the bushing (110) .
The apparatus (100) of claim 2, wherein the communication unit (104) is further configured to transmit the sensor signal to the external device.
The apparatus (100) of claim 2, further comprising:

an antenna (204) arranged on the end surface (400) of the bushing (110) separately from the communication unit (104) , and configured to transmit the sensor signal to the external device.
The apparatus (100) of claim 1, wherein the magnetic loop (106) is arranged to surround a protruding portion of the bushing conductor (120) from the end surface (400) of the bushing (110) .
The apparatus (100) of claim 6, further comprising:

a power management unit (802) configured to supply power to the current sensor (102) , wherein the power management unit (802) is powered by the magnetic loop (106) or by an external power source.
The apparatus (100) of claim 1, wherein the communication unit (104) comprises a transceiver antenna (502) , and

wherein an inner diameter of the transceiver antenna (502) is equal to or greater than an outer diameter of the bushing conductor (120) , and an outer diameter of the transceiver antenna (502) is equal to or less than a diameter of the end surface (400) of the bushing (110) .
The apparatus (100) of claim 5, wherein an inner diameter of the antenna (204) is equal to or greater than an outer diameter of the bushing conductor (120) , and an outer diameter of the antenna (204) is equal to or less than a diameter of the end surface (400) of the bushing (110) .
The apparatus (100) of claim 5, wherein the antenna (204) has a C-like or fan shape.
The apparatus (100) of claim 1, wherein the current sensor (102) and the communication unit (104) are attached onto the end surface (400) of the bushing (110) by glue or clamp.
The apparatus (100) of claim 5, wherein the temperature sensor (202) and the antenna (204) are attached onto the end surface (400) of the bushing (110) by glue or clamp.
The apparatus (100) of claim 1, wherein the communication unit (104) comprises a transceiver antenna (502) configured to transmit the current signal based on radio frequency identification.
The apparatus (100) of claim 5, wherein the antenna (204) is configured to transmit the sensor signal based on the radio frequency identification.
The apparatus (100) of any of claims 1-14, wherein the external device comprises a reader arranged in a switchgear and configured to receive the current signal via a reader antenna arranged in the switchgear.
An apparatus (200) comprising:

a temperature sensor (202) arranged on an end surface (400) of a bushing (110) at which a cable accessory (200) is coupled to the bushing (110) , and configured to sense a temperature of a bushing conductor (120) in the bushing (110) and to generate a sensor signal representing the sensed temperature; and

an antenna (204) of a C-like or fan shape, the antenna (204) arranged on the end surface (400) of the bushing (110) and configured to transmit the sensor signal to an external device.
The apparatus (200) of claim 16, further comprising:

a redundancy temperature sensor (604) arranged on the end surface (400) of the bushing (110) , and configured to sense the temperature of the bushing conductor (120) in the bushing (110) and to generate a further sensor signal representing the sensed temperature; and

a redundancy antenna (606) arranged on the end surface (400) of the bushing (110) separately from the antenna (204) , and configured to transmit the further sensor signal to the external device.
The apparatus (200) of claim 16, further comprising:

a current sensor (102) arranged on the end surface (400) of the bushing (110) , and configured to generate a current signal representing a current flowing through the bushing conductor (120) in the bushing (110) .
The apparatus (200) of claim 18, further comprising:

a communication unit (104) arranged on the end surface (400) of the bushing (110) separately from the antenna (204) , and configured to transmit the current signal to the external device.
The apparatus (200) of claim 18, wherein the antenna (204) is further configured to transmit the current signal to the external device.
The apparatus (200) of claim 16, wherein the temperature sensor (202) is arranged to be in thermal contact with a protruding portion of the bushing conductor (120) from the end surface (400) of the bushing (110) .
The apparatus (200) of claim 16, wherein an inner diameter of the antenna (204) is equal to or greater than an outer diameter of the bushing conductor (120) , and an outer diameter of the antenna (204) is equal to or less than a diameter of the end surface (400) of the bushing (110) .
The apparatus (200) of claim 19, the communication unit (104) comprises a transceiver antenna (502) , and

wherein an inner diameter of the transceiver antenna (502) is equal to or greater than an outer diameter of the bushing conductor (120) , and an outer diameter of the transceiver antenna (502) is equal to or less than a diameter of the end surface (400) of the bushing (110) .
The apparatus (200) of claim 16, wherein a radian of the C-like or the fan-shape ranges from 20° to 360°.
The apparatus (200) of claim 24, wherein the radian is 180°.
The apparatus (200) of claim 16, wherein the temperature sensor (202) comprises at least one of a thermocouple, a thermistor, a negative temperature coefficient element, a molybdenum electrical, and a semiconductor device.
The apparatus (200) of claim 16, further comprising:

a power management unit (902) configured to supply power to the temperature sensor (202) , wherein the power management unit (902) is powered by energy harvesting by a radio frequency wave or by an external power source.
The apparatus (200) of claim 19, wherein the antenna (204) is configured to transmit the sensor signal based on radio frequency identification, and

wherein the communication unit (104) comprises a transceiver antenna (502) configured to transmit the current signal based on the radio frequency identification.
The apparatus (200) of any of claims 16-28, wherein the external device comprises a reader arranged in a switchgear and configured to receive the sensor signal via a reader antenna arranged in the switchgear.
An Internet of Things (IoT) system (1000) comprising:

a wireless sensing apparatus (1002) comprising the apparatus (100) according to any of claims 1-15 or the apparatus (200) according to any of claims 16-29.