Shrinkable cable joint and voltage sensor
A shrinkable cable joint includes a joint insulating layer that surrounds a connection region configured to house two connected cable ends. A joint semiconductive layer surrounds the joint insulating layer. A joint screen layer surrounds the joint semiconductive layer. A joint sheath surrounds the joint screen layer. A capacitive voltage sensor is arranged between the joint screen layer and the joint semiconductive layer. The capacitive voltage sensor includes a sensor insulating layer having a first side and an opposite second side; a sensor electrode and a guard electrode arranged on the second side and directly contacting the joint semiconductive layer; and a sensor conductive layer arranged on the first side. The sensor conductive layer includes a first conductive layer portion in direct contact with the joint screen layer and electrically coupled to the guard electrode and a second conductive layer portion electrically coupled to the sensor electrode.
1. A shrinkable cable joint comprising:
a joint insulating layer surrounding a connection region configured to house two connected cable ends;
a joint semiconductive layer surrounding the joint insulating layer;
a joint screen layer surrounding the joint semiconductive layer;
a joint sheath surrounding the joint screen layer; and
a capacitive voltage sensor arranged between the joint screen layer and the joint semiconductive layer, the capacitive voltage sensor comprising:
a sensor insulating layer having a first side and an opposite second side;
a sensor electrode and a guard electrode arranged on the second side and directly contacting the joint semiconductive layer; and
a sensor conductive layer arranged on the first side and comprising a first conductive layer portion in direct contact with the joint screen layer and electrically coupled to the guard electrode and a second conductive layer portion electrically coupled to the sensor electrode, the sensor conductive layer extending on the first side.
2. The joint of claim 1 , wherein the capacitive voltage sensor has a planar structure and a rectangular shape, quadrangular shape, or circular shape.
3. The joint of claim 1 , wherein the capacitive voltage sensor is flexible.
4. The joint of claim 1 , further including an insulating filler arranged to electrically insulate the first conductive layer portion from the second conductive layer portion.
5. The joint of claim 1 , wherein the first conductive layer portion has a first area greater than a second area of the second conductive layer portion.
6. The joint of claim 1 , wherein the sensor electrode, the guard electrode and the conductive layer comprise a material selected from: metal, carbon, carbon nano-tube, a conductive polymer, or composites thereof.
7. The joint of claim 1 , wherein the sensor insulating layer comprises a material selected from: polyester, polyethylene terephthalate, polyethylene naphthalate, or polyimide.
8. The joint of claim 1 , wherein the capacitive voltage sensor is made according to a Flexible Printed Circuit (FPC) Technology.
9. The joint of claim 1 , wherein the sensor insulating layer comprises:
a first conductive element connecting the guard electrode with the first conductive layer portion; and
a second conductive element connecting the sensor electrode with the second conductive layer portion.
10. The joint of claim 1 , further comprising a signal cable comprising:
a first conductor having a first end connected to the second conductive layer portion and a second end connected to an output port; and
a second conductor having a third end connected to the first conductive layer portion of the sensor conductive layer and a fourth terminal coupled to the output port.
11. The joint of claim 10 , wherein the signal cable is a coaxial cable, a twisted-pair cable, or a shielded flat cable.
12. The joint of claim 1 , wherein the capacitive voltage sensor is arranged so as to detect a voltage signal (V out ) dependent on:
a capacitance value (C 1 ) associated with the joint insulating layer;
a first resistance value (R 12 ) associated with a portion of the joint semiconductive layer faced to a longitudinal region extending between the sensor electrode and a first portion of the guard electrode; and
a second resistance value (R 24 ) associated with a further portion of the semiconductive layer faced to a further region extending between the sensor electrode and a second portion of the guard electrode, the sensor electrode being arranged between the first portion and the second portion.
13. A power distribution system comprising:
two cable conductors spliced in a shrinkable cable joint, the shrinkable cable joint comprising:
a joint insulating layer surrounding a connection region configured to house the spliced cable conductors;
a joint semiconductive layer surrounding the joint insulating layer;
a joint screen layer surrounding the joint semiconductive layer;
a joint sheath surrounding the joint screen layer; and
a capacitive voltage sensor arranged between the joint screen layer and the joint semiconductive layer, the capacitive voltage sensor comprising:
a sensor insulating layer having a first side and an opposite second side;
a sensor electrode and a guard electrode arranged on the second side and directly contacting the joint semiconductive layer; and
a sensor conductive layer arranged on the first side and comprising a first conductive layer portion in direct contact with the joint screen layer and electrically coupled to the guard electrode and a second conductive layer portion electrically coupled to the sensor electrode, the sensor conductive layer extending on the first side.