BCTC/BC Hydroʹs operational experience with Distributed Temperature Sensing (DTS) Systems for Transmission Cables. Presented by

Transcription

1 BCTC/BC Hydroʹs operational experience with Distributed Temperature Sensing (DTS) Systems for Transmission Cables Presented by S. Cherukupalli Transmission Cables Design BC Hydro at the ICC Spring Meeting, St. Petersburgh on March 11,

2 OVERVIEW OF PRESENTATION Theory of Distributed Temperature Sensing. What is the technology application? Who are the suppliers and what are the issues related to testing of these equipment in a utility environment? Describe the BC Hydro/BCTC installations. Describe the type of on-site calibrations and some of the challenges experienced. Describe some desirable features of processing data from a utility perspective. 2

3 WHAT IS DTS? By using only one optical fiber, you can measure actual temperature distribution along the entire fiber in real time, without data transmission devices. Sensor is telecommunication-grade fiber itself, it is compact, lightweight, easy to install, and immune from Electro-magnetic Interference (EMI). 3

4 CONCEPT OF DTS Flash movie courtesy Brad Ellerman 4

5 RAMAN SCATTERING Optical Fiber Sensor DTS Unit Cool water Raman Scattering Anti-Stokes light Injected light Stokes light Molecular vibration weak Scattering Intensity weak Hot water large strong 2 Components of Raman Scattering Rayleigh light Anti-Stokes Stokes λas λo λst 5

6 SPATIAL INFORMATION DTS Unit Optical Fiber Sensor Cool water Hot water Thermal anomalies OP-Thermo t1 L1 Raman Scattering Light t2 L2 Distance is obtained from the roundtrip - time of Raman Scattering Light 6

7 DTS SYSTEM FEATURES High Reliability and Long Life Time of Light Source (MTBF >200,000 hours ) High Speed of Signal Processing Circuit Low Noise and Wide Bandwidth of Photodetector Circuit Useful and excellent GUI control software on PC Total support of system (from fiber sensor until software) Light Source RAMAN SCATTERING PC Signal Processing Circuit Photo - detector DTS Main Unit Optical Fiber (GI 50/125μm) 7

8 TYPICAL DTS SYSTEM Alarm Output PERSONAL COMPUTER Control Main Unit Optical Switch Fiber-optic Sensor Temp.Info. PC Controls OP- Thermo, saves the measured temperature data, and outputs alarm on its display. The light pulse is injected from one end of an optical fiber, and back scattering (Raman Scattering) is measured. By using Optical Switch,several Fiber-Optic Sensors can be measured one after another (Max.16CH). By using only optical fiber, you can measure actual temperature distribution along the entire fiber, at real time, without data transmission devices. 8

9 SUPPLIERS OF DTS EQUIPMENT SENSA Schlumberger (UK) (30km, 2m resolution, 0.5 C) Sensornet (UK) (30km-2m resolution, 0.05 C) SensorTran (Austin, USA) Sumitomo Corporation (Japan) Luna Innovations (Blacksburgh, Virginia) (10mm ±0.1 C) USi representing Agilent 12km, 1m, 0.1 C) LIOS (Germany) (0.5m to 1m resolution) Hitachi (Hitele) 30km, ±1.0 C 9

10 ISSUES RELEVANT TO UTILITY-1 How many channels do we need? What is the monitoring distance in km? What kind of spatial resolution (1m?) do we need? Temperature accuracy (±1.0 C adequate?) What should be the response time? 10

11 ISSUES RELEVANT TO UTILITY-2 Are the results repeatable? How does one specify the equipment How does one undertake site calibration? What are EMC compliance requirements? Do I need local data storage? How do I communicate with the device? Do I need to integrate this data with Power System Control Centre? 11

12 Examples of BC Hydro installations BC Hydro has been using DTS Technology from Monitoring 69kV circuits in the downtown core. Along spare duct on a 49-year old cable system (2L40). Along spare duct on a 49-year old cable system (2L50). Along a spare duct on a brand new 230kV SCFF cable (2L33). Retrofitted in the conductor of a 525 kv AC submarine cable installation. BC Hydro/BCTC have four DTS units that range from 2km to 10km systems. 12

13 PHOTOS OF SOME INSTALLATIONS 13

14 BLOWING FIBER INTO SPARE DUCT 242 kv SCFF Cable 3.5km long FO Cable blown into duct 14

15 FO CABLE IN SPARE DUCT 242 kv SCFF CABLE 9km long 15

16 MITIGATION AT STEAM CROSSING Duct bank Insulation on Steam crossing Copper straps 16

17 MITIGATION AT STEAM CROSSING 17

18 THERMAL BACK-FILL 18

19 DTS SYSTEM MONITORING A HPFF CABLE 19

20 525kV Submarine Cable Terminal Station Low-low water mark 20

21 CROSS-SECTION of THE 525 kv CABLE 155 mm dia 21

22 GENERAL ARRANGEMENTS 22

23 FIBER INSTALLATION 23

24 HIGH-ALTITUDE OPTICAL SPLICING 24

25 DTS Units at Two sites 25

26 DTS CALIBRATION 26

27 DTS On-site calibration Calibration of loop near base of termination Calibration of loop at the top of the pothead 27

28 RESULTS 28

29 RESULTS ALONG A 69kV CABLE 60L52 - Fiber # Temperature Distance (m) 29

30 EFFECTS OF MITIGATION Cct. 60L51 & 60L53 - Steam Beatty St 500mm Steam Pipe Crossing Under (2.9m down to Top of Ductbank) Grade 2.2 m mm Dia. Steam Pipe Dec Jan Mar Apr Jun-99 8-Aug Sep Nov-99 5-Jan Feb Apr-00 Temp (C) Remediation Excavate & Insulate Feb. 13, m. C F B A 0.5 m. C A B View tow ard Murrin Steam Manhole Fiber Re-located in Ductbank March 24 Date 30

31 MEASUREMENTS WITH WATER CIRCULATION 40 DTS Measurements along 60L51/53 During Water circulation in ducts between two manholes (MH # KQ to KP) 35 Temperature (deg C) Before water circulation 5 After water circulation Location along the optical cable 31

32 RESULTS FROM STEAM CROSSING ACROSS HPFF CABLE Steam crossing 32

33 MEASUREMENTS ALONG A NEW 230kV CABLE Temperature measurements along 2L33 from HPN-CSQ on Fibre 1 on Apr 28 at 14:17 HPN Temperature (deg C) MH 3759 Near steam crossing CSQ MH Near water main Distance (m) 33

34 RESULTS FROM 525kV CABLE 70 Alarm Threshold 60 DTS Temperatures (deg C) CONTROL ROOM Warning Threshold Traces for G1 at 8:00 and 16:00 hrs FIMT loop in the corona shield of cable termination measuring air temperature Cable G2 Change in cable conductor temperature attributed to the tidal charges cooling the section in the ocean Cable G3 Cable G4 Cable G5 REMOTE FIBRE END 10 Cable G Distance along fibre from control room (m) 34

35 ARCHITECTURE- An option? * 35

36 Desired features of DTS System Local data storage Remote access to unit Data reliability and consistency Ease of equipment use Warning alarms System integration 36

37 QUESTIONS? 37