How to use smart temperature monitoring for power grid equipment

Faseroptischer Temperatursensor, Intelligentes Überwachungssystem, Verteilter Glasfaserhersteller in China

In the power system of the grid, grid equipment is an indispensable part. To ensure the normal operation of grid equipment, grid monitoring personnel are needed to measure and record the real-time status of the grid. According to statistics, various electrical equipment failures in transmission lines are closely related to their heating. At present, intelligent temperature measurement devices for power grid equipment mostly use peripheral power supplies, which are connected to the power supply through lines. Aber, the lines will age over time, and monitoring personnel also need to pay attention to the use of peripheral circuits to prevent power outages and inability to work caused by the aging of the lines of the intelligent temperature measurement devices for power grid equipment. Moreover, the high installation height of the power grid poses certain difficulties for the installation of intelligent temperature measurement devices for power grid equipment. Due to the limited measurement range, multiple sets of devices need to be used in conjunction to ensure the accuracy of measurement data. Sometimes even drones are needed to assist in temperature measurement, which increases the difficulty and cost of temperature measurement.

Temperature measurement scheme for power grid

There are several temperature measurement methods in the power grid, and FJINO will introduce several common temperature measurement schemes below.

1. Thermocouple resistance temperature measurement

The disadvantage of using conventional devices such as thermocouples, thermistors, and semiconductor temperature sensors to detect grid junction temperature is that it cannot be wirelessly passive, requires metal wires to transmit signals, cannot work independently wirelessly, and insulation performance cannot be guaranteed.

2. Infrared temperature measurement method. Infrared temperature measurement is a non-contact temperature measurement method that is widely used in temperature detection of equipment such as substation sleeves, lightning arresters, and busbars. Its disadvantage is that the accuracy of indirectly obtaining temperature data through infrared spectra cannot meet the requirements. The level of computer recognition technology for infrared spectra cannot replace manual recognition, and the degree of automation is not high, so it is not widely used. Disadvantages: It requires manual labor, non-contact temperature measurement, and cannot be detected beyond the line of sight, resulting in low temperature measurement accuracy.

3. Wireless temperature measurement method. The use of wireless temperature measurement devices to detect the temperature of power grid contacts requires regular battery replacement, and the working temperature of wireless communication modules is limited.

4. Fiber optic temperature measurement

The use of optical fibers to transmit temperature signals has the characteristics of insulation, anti-interference, and high voltage resistance. Fluorescence fiber temperature measurement technology has absolute advantages in these fields because it has no additional heating caused by conductive parts and is not affected by electromagnetic fields.

Application fields of power grid fiber optic temperature measurement:

1. Distributed fiber optic temperature measurement in cable tunnels

A device composed of a temperature measurement control host, a temperature measurement optical cable, etc., that monitors the temperature of the power cable body, accessories, and the environment. The distributed fiber optic temperature monitoring system uses laser pulses to enter from one end of the fiber optic cable for temperature measurement. During the forward propagation process, the fiber optic molecules interact with each other and undergo various types of scattering. Among them, due to the thermal vibration of the fiber optic molecules, a light longer than the wavelength of the light source and a light shorter than the wavelength of the light source are generated. The intensity of the shorter wavelength light is more sensitive to temperature. The temperature information of any point in the optical waveguide can be obtained from the ratio of the intensity of the two long and short wavelength light signals at that point. The principle of optical time domain reflectometry (OTDR) is used to locate these hotspots by the transmission speed of light waves in the optical fiber and the time of the backscattered light. By utilizing the above technical principles, distributed measurement of the temperature field along the optical fiber can be achieved.

2. Fluorescent fiber optic temperature measurement for switchgear

The temperature detection of heating elements such as switchgear contacts, knife switches, busbar busbars, and incoming and outgoing lines can be used inside the switchgear.

Fluorescent fiber optic temperature sensors have obvious advantages such as anti electromagnetic interference ability, good stability, high sensitivity, miniaturization, light weight, and contact temperature measurement. Deshalb, fluorescent fiber optic temperature sensors are used for online monitoring of electrical equipment switchgear.

3. Transformer winding temperature measurement

Dry type transformer three-phase winding temperature measurement, oil immersed transformer winding fluorescent fiber temperature measurement. The application of fiber optic temperature measurement technology in monitoring the hot spot temperature of transformer windings has the advantages of convenience, accuracy, safety, and reliability. It can timely and accurately detect defects and hidden dangers such as winding overheating, which is of great significance for improving the safe and stable operation of transformers.

4. Rail Transit

Traditional PT100 temperature measurement cannot be used on rail transit because strong electromagnetic interference is generated when the subway passes by, and only fluorescent fiber optic temperature measurement can be used. It can be used on large power equipment such as main transformers and rectifier transformers. The fiber optic temperature measurement system has been widely used in domestic subway lines such as Line 1. Please feel free to contact us for a one-stop solution for track temperature measurement and customer cases.