JPS59126926A - Temperature measuring device of conductor of power cable - Google Patents

Abstract

PURPOSE:To measure the temperature of a conductor safely and surely from the outside, by converting the temperature detected from the conductor to an optical signal and using an optical fiber to transmit the temperature signal to the outside. CONSTITUTION:A measuring probe 3 consisting of a thermocouple or the like which measures the temperature of a conductor 2 is inserted to the conductor 2 of a cable 1. This measuring probe 3 is connected to a temperature measuring device 4 which is installed in a cable head terminal part, and the temperature is converted to an electric signal there. The signal converted to the electric signal is inputted to an optical signal generator 5 and is converted to an optical signal. This optical signal is transmitted from a high voltage part to a low voltage part by an optical fiber 6 and is inputted to an optical signal receiver 7 and is converted to an electric signal. This signal is inputted to an alarm signal display or temperature display device 8 to display the temperature or generate an alarm.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the l:+rr degree measurement of electrical cables, particularly high voltage and ultra-high voltage electrical cables.

Electric cables transport electricity by passing current through a conductor. What limits the amount of power transported is the permissible temperature of the conductor, which is primarily limited by the heat resistance of the surrounding insulation.

However, in reality, conductor temperature is generally detected directly at the high voltage application section, which is extremely dangerous. It is difficult to make current flow close to the capacitance temperature limit, which can only be estimated by calculation.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a technique for accurately measuring the conductor temperature of even a high voltage cable from the outside.

According to the present invention, the above object is achieved by converting the temperature detected in the conductor into an optical signal and transmitting the temperature signal to the outside using an optical piper. The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 is a circuit diagram showing the principle of the present invention. . First, a measurement probe 3 such as a thermocouple for measuring the conductor temperature is inserted into the conductor 2 of the cable 1 . This is connected to a temperature measuring device 4 installed at the end of the cable head, where the temperature is converted into an electrical signal.

The power supply for this measuring device 4 is provided by rectifying the induced current from the current flowing through the cable 1 using a suitable device 12, or by storing power obtained by a solar cell in a storage battery.
It may be supplied from now on.

The signal converted into an electrical signal then enters an optical signal generator 5 and is converted into an optical signal. This optical signal is transmitted from the high voltage section to the low voltage section through the optical fiber 6, enters the optical signal receiver 7, and is converted into an electrical signal. This signal then enters the alarm signal display or temperature display device 8 to display the temperature or issue an alarm.

FIG. 2 is a schematic diagram of the device shown in FIG. 1 applied to a cable terminal structure. In FIG. 2, a probe 3, a temperature measuring device 4, and an optical signal generator 5 are connected to the end of the cable 1.
is built in, and temperature information is taken out from there through an optical fiber 6.

The above description has been about measuring the temperature at the end of the cable, but the temperature at the joint can also be measured using an optical fiber, and the signal can be transmitted to the outside via the optical fiber.

Optical fiber is a good electrical insulator, and according to the present invention, it is installed inside the cable head to send signals from the high voltage section to the low voltage section.According to the present invention, the temperature signal on the cable conductor side to which high voltage is applied can be transmitted safely and reliably to the ground. This is a major advantage that could not be achieved with the prior art.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the principle of the conductor temperature measuring device of the present invention, and FIG. 2 is a schematic diagram of the same device applied to measuring the temperature of a conductor at a cable end. l...Electrical cable, 2-Conductor, 3-Temperature measuring glove, 4-Temperature measuring device, 5 Optical signal generator, 6-Optical fiber, 5-17 Optical signal receiving device, 8-Alarm signal display or temperature display Device, 10.-Lower metal fitting, 11.. Insulator tube, 12. Power source extraction device from the energized current.

Claims (1)

[Claims] A high voltage (full device) consisting of a claw 11 constant element that measures the temperature inside the conductor of the electric cable, a temperature measuring device 7j that converts this into an electric signal, and an optical signal generator that converts it into an optical signal, and a high voltage (full) device that receives the optical signal. A low voltage (1111) device consisting of an optical signal receiver Is that displays the signal and a temperature display device that displays the signal, the optical signal generator of the same pressure side device, and the optical signal receiver of the upper encasing low voltage side device. 1. An apparatus for measuring the temperature of a conductor of a power cable, comprising: an optical fiber provided therein;