A device for simulating intermittent arc grounding faults in a power distribution network includes a sliding rail, a first and a second support frames, an insulated electrode disk, and an electrode disk motor. The first support frame is fixed on the left side of the slide rail, and the position of the second support frame relative to the first support frame can be adjusted through the sliding rail. The second support frame is provided with an electrode disk motor for driving the insulated electrode disk to rotate. An upper and a lower conductive bars are installed on the first support frame, their adjacent ends provided with an upper and a lower arc-shaped conductor sheets, and the insulated electrode disk having two circles of conductive pillars is located between the conductor sheets. The conductor sheets are respectively installed on the side of the conductive bars close to the conductive pillar.

A smart sheath for the protection of an electric cable comprises an inner insulating tubular layer (3) adapted to contain the conductive elements (4) of the electric cable (1), an outer tubular protective layer (5) placed on the inner tubular layer (3), coaxially thereto, an electric control circuit (6) arranged inside the outer tubular layer (5) and adapted to intercept the induced electric currents generated by the passage of the electric current in the conductive elements (4). Furthermore, the electric control circuit (6) is operatively connected to electric current sensor means (7) and to microcontrollers (13) adapted to discriminate a value of the induced electric current higher than a predetermined maximum value to signal an overload inside the electric cable (1) or absence of the induced electric current for report a possible short-circuit.

A smart sheath for the protection of an electric cable comprises an inner insulating tubular layer (3) adapted to contain the conductive elements (4) of the electric cable (1), an outer tubular protective layer (5) placed on the inner tubular layer (3), coaxially thereto, an electric control circuit (6) arranged inside the outer tubular layer (5) and adapted to intercept the induced electric currents generated by the passage of the electric current in the conductive elements (4). Furthermore, the electric control circuit (6) is operatively connected to electric current sensor means (7) and to microcontrollers (13) adapted to discriminate a value of the induced electric current higher than a predetermined maximum value to signal an overload inside the electric cable (1) or absence of the induced electric current for report a possible short-circuit.

An interactive test equipment for quality evaluation of an insulative electric resistance value of an electric power cable at least includes a control unit, a test question type module and an operating module. The test question type module includes at least a test set. Each of the at least a test set includes at least an electric resistance value measuring part each of which has an electric voltage value display and an electric resistance value display to respectively display electric voltage values and electric resistance values of a corresponding cable. Besides, the operating module is used to initiate the interactive test equipment, to select answers, and the control unit is used to load question types and to make judgment on answers. Accordingly, test subjects are authenticated and evaluated for a judgment ability thereof in order for ensuring safety of a working environment.

A method, system and apparatus of fault detection in line protection for a power transmission system. A voltage (u) at a measurement point on an electrical line is obtained. The measurement point is a point at which a protection device for the line protection is installed. A current (i) at the measurement point is further obtained and a differential value of the current is determined. Then, a voltage (u.sub.q) at a setting point on the electrical line is determined from the voltage (u) at the measurement point, the current (i) at the measurement point and the differential value of the current (i) according to a time domain lumped parameter model for the electrical line. The voltage change between the determined voltage at the setting point during the fault period and a voltage at the setting point determined during a pre-fault period can be further determined. The fault detection can be performed based on the determined voltage change and a fault threshold. It can ensure voltage determination accuracy and detection reliability with a low sampling rate. Moreover, the solution can work right after the fault inception, almost no waiting time is required, and thus it may achieve a super-fast line protection.

The present disclosure relates to a submersible apparatus (1) for testing a submarine high voltage (HV) cable system. The apparatus (1) includes a cable termination (100) including an electrical insulator (101) and a shielding electrode (102) for the electrical connection with a cable end (201). The apparatus (1) additionally includes a cable bend restrictor (300) having a through channel (301), and a termination locking (400) in through communication with the cable bend restrictor (300) and the cable termination (100). According to another aspect, a method for testing a submarine high voltage (HV) cable apparatus using the above testing apparatus (1) is additionally disclosed.

The present disclosure relates to a submersible apparatus (1) for testing a submarine high voltage (HV) cable system. The apparatus (1) includes a cable termination (100) including an electrical insulator (101) and a shielding electrode (102) for the electrical connection with a cable end (201). The apparatus (1) additionally includes a cable bend restrictor (300) having a through channel (301), and a termination locking (400) in through communication with the cable bend restrictor (300) and the cable termination (100). According to another aspect, a method for testing a submarine high voltage (HV) cable apparatus using the above testing apparatus (1) is additionally disclosed.

A main electrical cabling is subject to variations in ambient temperature over its length. A detection system for detecting fault in the main electrical cabling able to cause a serial arc, or heating within a connection, includes a monitor electrical cabling placed as a return loop alongside the main electrical cabling, a monitoring device, and a return cable bringing back electrical potential at the output of the main electrical cabling to the monitoring device. The monitoring device includes a controllable current generator injecting, into the monitor electrical cable, a current dependent on current flowing through the main electrical cabling. Electronic circuitry determines a difference in voltages at inputs and outputs of the main electrical cabling and of the monitor electrical cabling, to detect a potential fault in the main electrical cabling leading to a serial arc or increase in temperature. A fault in the main electrical cabling is detected despite variations in temperature.

A main electrical cabling is subject to variations in ambient temperature over its length. A detection system for detecting fault in the main electrical cabling able to cause a serial arc, or heating within a connection, includes a monitor electrical cabling placed as a return loop alongside the main electrical cabling, a monitoring device, and a return cable bringing back electrical potential at the output of the main electrical cabling to the monitoring device. The monitoring device includes a controllable current generator injecting, into the monitor electrical cable, a current dependent on current flowing through the main electrical cabling. Electronic circuitry determines a difference in voltages at inputs and outputs of the main electrical cabling and of the monitor electrical cabling, to detect a potential fault in the main electrical cabling leading to a serial arc or increase in temperature. A fault in the main electrical cabling is detected despite variations in temperature.

Systems and methods for inductance compensation in a welding-type system include a reel configured to wind a welding-type cable to reduce a first portion of the welding-type cable extending from the reel, and to unwind to increase the first portion of the welding-type cable extending from the reel, wherein a second portion of the welding-type cable is at least partially wound around the reel when stored. A controller determines a first length of the first portion of the welding-type cable, calculates a first inductance of the first portion of welding-type cable extending from the reel based on the first length, determines a second length of the second portion of the welding-type cable, calculates a second inductance of the second portion of welding-type cable wound around the reel based on the second length, and calculates a cable inductance of the welding-type cable based on the first inductance and the second inductance.