Distributed fiber optic online temperature measurement

OneIndustry background

With the development of society and the continuous increase in demand for electricity, the load on the power grid will continue to increase. Although the likelihood of accidents is extremely low, there are still a certain number of cases of power grid accidents. And the analysis of these cases shows that the working temperature of the cables at that time had exceeded their maximum limit working temperature, so it is necessary to analyze the dynamic current carrying capacity of the cables to reduce or even eliminate the above-mentioned accident hazards.

For cables, cable structures, and other cables that have already been put into operation, their phase and spatial relationships, as well as the voltage and frequency of the load, have been determined. The total heat generation of the cable is only related to the conductor temperature. The correspondence between environmental temperature, sheath surface temperature, cable core temperature, and current carrying capacity can be established through cable current carrying capacity analysis software (hereinafter referred to as software), achieving non-contact online diagnosis of cable core temperature and ensuring the safe operation of cables.

IIaccording to the standard

ØQGDW 1814-2013 "Power Cable LinesDistributed Fiber Optic Temperature Measurement SystemThe Technical Specification specifies the verification experiments for conductor temperature calculation and dynamic current carrying capacity calculation.

ØDLT1253-2013 "Operation Regulations for Circuit and Cable Lines" specifies the allowable current carrying capacity of cables and the maximum allowable temperature of cable conductors under different laying conditions.

ØDLT 1573-2016《power cableDistributed Fiber Optic Temperature Measurement Systemtechnical specificationsHow to translate

The basic functions of monitoring computer software are specified in the document: temperature calculation of cable conductors, dynamic current carrying capacity calculation of cable conductors, data storage, and event recognition.

3.1 III

System Principles

3.2 Principle of Distributed Fiber Optic Temperature Measurement System

The distributed fiber optic temperature measurement system can simultaneously achieve temperature measurement and spatial positioning functions, and obtain accurate temperature information along the fiber optic distribution in real time; By combining advanced fire intelligent alarm judgment algorithms, real-time online monitoring of the entire sensing fiber optic process can be achieved.

3.3 Principle of operating current acquisition host

The operating current of the cable is measured using a Roche coil. A complete Roche coil current measurement system should include a coil and an integrator. The electromotive force measured by the Roche coil can be integrated through an integrator to restore the current in the conductor.Principle of Cable Current Carrying Capacity Analysis Software

The cable current carrying capacity analysis software can monitor the surface temperature, ambient temperature, and operating current of the cable in real-time and across the entire range. Adopting International Electrotechnical Commission standardsThe IEC60287 and IEC60853 algorithm models provide powerful assistance for real-time calculation of conductor temperature, steady-state current carrying capacity, and dynamic current carrying capacity in cable safety monitoring and load management.4

Distributed fiber optic online temperature measurementProduct FeaturesUpload on IoT platform

:Realize real-time uploading of current, temperature and other data to the Internet of Things platform, and achieve remote monitoring and cloud computing through the cloud platform, without local restrictions and quickly detecting current and responding in a timely manner, thus better protecting cable equipment.Real time data analysis

:Real time monitoring of cable operating current, ambient temperature, cable surface temperature, and cable conductor temperature, facilitating analysis of cable operating status.Steady state current carrying capacity calculation:Users only need to set the basic parameters of the relevant cables, inCable current carrying capacity analysis software

indeedBy specifying the cable model and surface temperature, the steady-state current carrying capacity of the cable can be calculated. Provide reference data for cable selection in the design department and adjustment of cable load in the scheduling department.Dynamic current carrying capacity calculation:Given any two of the three values of temperature, time, and current, the third value can be calculated.

canTo help evaluate the remaining load capacity of cables online, assist dispatchers in making reasonable decisions in load allocation, and achieve dynamic capacity expansion of power cables, reducing investment in transmission line construction.Five

Distributed fiber optic online temperature measurementSystem networking

The network diagram of the dynamic monitoring system for cable current carrying capacity is shown in the figure1

As shown in Figure 1.imageØCable surface and environmental temperature collection: Fiber optic temperature measurement hostReal time measurement of temperature information along the cable laying direction, and thenTransmitting temperature information to the upper computer through a local area network

software.

ØSoftware: Within the local area network, temperature information collected by the fiber optic temperature measurement host and current information collected by the operating current software will be uploaded to the software uniformly.

ØIoT platform: Data in the software can be transmitted to the IoT platform via Ethernet.

VISoftware features

The main interface of the software is shown in the figure2

4

5

6

6.1 As shown in Figure 2. Attention: Each set of software is bound to the server. If the software is installed on other servers randomly, it may cause the software to fail to run.

image3Temperature monitoringAs shown in the figure）As shown, it is the temperature monitoring pageThe page is divided into three parts,The top is the basic information of the selected fiber optic cableOn the left is the real-time temperature curve, and on the right is the list of alarm information,

You can click on the channel number to switch between displaying different channels3

6.2 Fiber optic temperature curve. The collection control buttons on the right, from left to right, are: start collection, stop collection, reset coordinates, and stop alarm sound.

imageCurrent carrying capacity analysisOpen it againcurrent-carrying capacity4On the page, select the corresponding cable channel from the left channel list, and the system calculates the cable current carrying capacity based on the real-time temperature collected,As shown in the figure

）4

6.3 shown

imageHistorical AlarmsHistorical alarms can be queried for alarm records based on time periods and channels5，As shown in the figure

）.5

6.4 Click to view the detailed information of the alarm record.

imagehistorical temperatureHistorical temperature data can be queried based on time periods and channels6，As shown in the figure）7，

Historical data can be quickly replayed based on the selected time period to quickly view changes in fiber temperature, as shown in the figure6

）. Click to view the historical record details.7

6.5 imageimage

collectSettingsThe collection settings can modify the system collection cardSettings、Storage settings, data reporting settingsOperating parameters of optical switch equipment，as8（

image8

6.6 ）

imageFiber optic settingsFiber settings allow you to view the currently configured fiber information and add, modify, and delete it9Temperature measuring fiber

Information, such as (Figure)9

）.image

6.6.1Fiber optic addition and modificationclickandYou can add and modify fiber optic information, and then fill in the relevant information in the opened window. Click10Readable fiber temperature data curve, click

It can automatically calculate the interval information of reference fiber and temperature measurement. As shown in the figure10

）image

6.6.2Fiber optic map path settingclickThe icon can be used to set the laying path of the fiber optic cable, such as11(image)

You can modify the city in the upper left corner of the newly opened window. Click 'Start Drawing' to draw the fiber optic laying path on the map, double-click to end the drawing. Click 'Clear Path' to clear the currently drawn path. Click 'Save' to save the currently drawn path. Click the upper right corner11

6.7 Refresh the map.

imageMonitoring interval settingThe monitoring area settings can be used to view and modify the monitoring area of configured fiber channels. Click12and

You can add and modify monitoring areas, as shown in the figure12

6.8 ）After filling in the information, click the "Save" button.

image13Steady state current carrying capacity calculation

The current carrying capacity calculation can be based on the selected cable and cable temperature to determine the current carrying capacity that the cable can withstand. As shown in the figure13

6.9 ）

imageCable information settingAdd cable information to the cable information settings, which requires a lot of filling in. Please fill in carefully to ensure that the data is correct14Like（image2）Filling in information is divided into cable parameter information and cable laying and other related parameters

part

.

The cable parameter information includes the conductor, conductor shielding layer, insulation layer, insulation shielding layer, inner lining layer, metal sheath, outer sheath, and external information of the cable.14