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Online Monitoring System for High Voltage Oil-Filled Terminations

IP.com Disclosure Number: IPCOM000250604D
Publication Date: 2017-Aug-08
Document File: 3 page(s) / 120K

Publishing Venue

The IP.com Prior Art Database

Abstract

The rapid development of power systems has led to the use of oil-filled cables in high voltage grid applications. Because of the long run time and equipment aging, the outer sheath of the oil-filled cables may develop leakage problems. A sensor system has been developed to monitor the oil pressure and the oil temperature to detect any oil leaks in the outer sheath to help ensure safe operation of the cable.

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Online Monitoring System for High Voltage Oil-Filled Terminations

The rapid development of power systems has led to the use of oil-filled cables in high voltage grid

applications. Because of the long run time and equipment aging, the outer sheath of the oil-filled

cables may develop leakage problems. A sensor system has been developed to monitor the oil

pressure and the oil temperature to detect any oil leaks in the outer sheath to help ensure safe

operation of the cable.

This publication describes a new online operation monitoring oil leakage, conductor temperature

and transmitting system for high voltage cable terminations. It mainly includes a controller unit

outside the termination and temperature and oil leakage detecting sensor inside the termination,

and sensors are installed on the base plate (36). See Fig. 2.

The temperature and oil leakage monitoring device has two sensors, a temperature sensor and a

pressure sensor, and calculates the oil height based on the oil pressure to estimate oil leakage.

The main components are shown in Fig. 1, and include:

1: A low frequency coil (21).

2: A ceramic capacitor (22), which can form a LC resonant circuit with the low frequency coil (21).

3: A rectifier circuit (23), which will convert the AC power to stable DC output Vout for the

controller (24).

4: A micro-controller (24).

5: A temperature sensor (25), which can be a temperature sensitive resistor, a thermocouple, or

any other suitable temperature sensor.

6: A pressure sensor (26),which can be a pressure tablet, a liquid level sensor, a pressure

sensitive resistor, or any other suitable pressure sensor.

FIG 1: System Block Diagram

FIG 2: Temperature and Oil Leakage Detecting System

As illustrated in Fig. 2, the controller unit (35) is connected to the temperature and oil leakage

detecting sensor. The oil pressure and temperature data are collected by the detecting sensor

and transmitted to the controller unit. The current transformer (37) provides the required power

source for the controller unit (35). The current transformer (37) is installed on the outside of the

high voltage cable (30). When a current flows through the cable (30), the current transformer (37)

will output a stable DC voltage.

The temperature and oil leakage monitoring device includes two sensors, a temperature sensor

and a pressure sensor, and calculates the oil height based on the oil pressure with the formula F

= ρ * ᵍ * Һ. If there is a leakage, the height of the oil will be smaller and smaller, and an alarm

signal will be sent to the maintenance...