Presentation Transcript

1. Submarine Cable SystemFunctions & Repair

2. IP Cloud
3. World Submarine NW Map
4. DWDM WDM (Wavelength Division Multiplexing), it uses different wavelengths on the same fibre & is totally protocol independent (SDH, ATM, Ethernet…) It is known as Dense Wavelength Division Multiplex (DWDM) when the wavelengths are close (a few nm.) For a DWDM Transmission system, 40/80 or at present 160 or more wavelengths in Optical C-Band (1530nm to 1565nm wavelength spectrum) can be carried on one fibre.
5. a) Overcome fiber exhaust / lack of fiber availability problems (better utilization of available fiber) b) Space and Power savings at intermediate stations c)Easiercapacityexpansion d) Cost effective transmission e) No O-E-O conversion delays f) Wave length leasing instead of Bandwidth leasing Why DWDM
6. Evolution of Submarine Transmission Technology SDH & DWDM combined SDH and DWDM are complementary. SDH provides: flexibility resilience in case of failure DWDM provides: very high bandwidth So For higher bandwidth transmission over a longer distance on the International network across continents/countries, SDH & DWDM combinely evolves to Submarine Transmission network
7. Submarine Fiber Optic Network system SLTE, PFE, LME, NMS and DCN Fully integrated Undersea System Using with - Cables Repeaters Branching Units Terminal Equipment
8. TerminalEquipment Power Feeding Equipment Cable Branching unit Repeater What makes a Submarine Cable Network Cable station Network Management
9. Undersea Cables
10. Double Armoured Cable – For Deep & Rocky Seabed for double protection
11. Functions of Submarine Network
12. Functions & Terminologies
13. Submarine Wetplant & components Wet plant comprises the following equipment/components: Undersea Cable Land Cable Optical Fiber Cable joints Undersea Repeaters Gain equalizers Branching Units
14. TRPDR Transponder HV : High Voltage LME : Line Monitoring Equipment OGPP : Ocean Ground Protection Panel PFE : Power Feed Equipment RL : Rodent Lightning TLA : Terminal Line Amplifier WTE : Wavelength Termination Equipment Major Components of Submarine system SLTE & Wetplant NMS NMS Cable Station SL-17UnderseaCable CTE Beach l 1 TRPDR Full Fiber DropBranching Unit RL Cable Joint WTE l TRPDR 2 N Channels + HV Power TLA ADM HV Shield l TRPDR 3 UnderseaRepeater STM-16/ STM-64 Ÿ PLINB Ÿ Ÿ l TRPDR n Ground Ocean LTE #1 Ground l TRPDR 1 OGPP PFE l TRPDR 2 N Channels ADM l TRPDR 3 Ÿ Building Ÿ Ground STM-16/ STM-64 Ÿ COTDR LME l TRPDR n LTE #2
15. TRPDR WTE l1 1 l2 2 ADM OneFiber-Pair 10 Gbps (S-64.2) Interface Line Amp IP lN-1 N x 10Gbps N-1 Submarine Cable lN ATM N OXC Submarine Transmission Line Terminating Equipment Note: Any module of the LTE may not be included depending on the specific requirements of the system (distance, bit rate, SDH or SONET equipment, etc.) (optional) ILE Line Monitoring Wavelengths (only for repeatered systems)
16. UnderSea Repeaters Repeaters use state-of-the-art optical amplifier technology to achieve high performance and reliability in the transmission of multiple wavelength channel signals on multiplefiber pairswhich normally use 980nm Pump for boosting up optical signal
17. Inside Repeater & different types 1/2/3/4 up-to 8 Amplifier pairs per Repeater Low/High Gain Repeaters. Low noise & Wide BW Repeaters 980 nm Pumps used in Repeaters.
18. Gain Equalisers Gain Equalizer function is needed for every 5-10 spans depending on the total length of system. It is required because of non-flat nature of EDFA amplifier to compensate the gain which results with wider range of wavelength for traffic.
19. Branching Unit Branching units (BUs) are designed for use in systems having three or more landing sites. Optical signals are routed among the three cables that connect to the BUs. There are different types of BU’s. These BU can be controlled for electrical connections relay from the landing station SLTE equipment using commands on the same Optical channel.
20. Types of BU Passive BU – The Electrical connections/branches can’t be switched or controlled from Station & it is electrically passive & doesn’t consume any electrical power. Also it is optically passive, means no Adding/Dropping of Wavelengths among three legs. Power Switched BU – This type BU provides controllable electrical connections among the three cable legs, as well as to the sea-ground electrode built into the trunk leg cable termination. The electrical connectivity within the 34A-Type BU is controlled on a powered system by means of an optical command signal & it will have a command receiver. Power Switched OADM BU – It is similar to Power switched BU, but having optical add/drop functionality using a OADM inside the BU, which makes it optically & electrically controllable among three legs. Non-power switched BU – It is similar to Passive BU, but having OADM functionality.
21. PFE Under Sea Repeaters requires power for operation of Electronics circuit & the Power Feed Equipment (PFE) provides power to the these repeaters & Power switched BU. These PFEs supply the power to undersea equipment in redundant arrangements called as dual end feed, for continuous operation even in the event of one PFE converter failure. Different types of PFE from all SubSea suppliers available, depending on the power supply capability to feed the system, like 10Kv, 5Kv etc.
22. PFE- PFE- PFE+ PFE+ Station B Station B Station A Station A PFE- PFE- Station D Station C PFE – Submarine System powering overview Current Virtual Ground Example of a Trunk Point to Point Powering System PSBU 1 PSBU 2 Current Example of a Normal Powering scenario for a Trunk and Branch Configuration
23. Fault Isolation & Repair in Wetplant Detection and localization of Subsea faults Two categories - Optical - Electrical Electrical and optical faults can occur simultaneously (cable break) and separately (damaged or broken fibers with the power path intact, and insulation fault between the power path and the sea, commonly known as shunt fault, with fibers intact.
24. Types of SubSea Fault Type 1 fault - Cable break for the cable being cut, with a break in the electrical insulation between seawater and the power-feeding conductor. Type 2 fault - Open fault for the cable being cut, without breaking the electrical insulation between seawater and the power-feeding conductor. Type 3 fault - Shunt fault for a break in the electrical insulation between seawater and the power-feeding conductor, without this conductor itself been cut. Type 4 fault - damage in the optical path without significant electrical alteration of the power-feeding conductor continuity and insulation. Outer Cable HV conductor Fiber Outer Cable
25. Fault Localization techniques Single-end DC measurements Type 1- Cable Break Type 3 – Shunt Fault Only accurate if you precisely remove contribution of repeaters and fault. Capacitive Method Type 2 - Open fault Conjugate Method (current-balance) Type 3 – Shunt Fault Accurate but also requires removal of contribution of the repeaters. Optical Path (OTDR/COTDR) Type 4 - Optical Fault only OTDR only good to first repeater. Electrical Path fault - Power Feed (output variation/ohms law) - PEFL (impedance mismatch) - DC Testing (IR, IC and CR) - Electroding (detection of a magnetic field due to applied tone)
26. Optical Fault Localization What is a OTDR? Optical Time Domain Reflectometer - also known as an OTDR, is a hardware device used for measurement of the elapsed time and intensity of light reflected on optical fiber. How it works? The reflectometer can compute the distance to problems on the fiber such as attenuation and breaks, making it a useful tool in optical network troubleshooting. The intensity of the return pulses is measured and integrated as a function of time, and is plotted as a function of fiber length. What is a COTDR? CoherentOptical Time Domain Reflectometer - also known as a COTDR, An instrument that is used to perform out of service backscattered light measurements on optically amplified line systems. How it works? A fiber pair is tested by launching a test signal into the out going fiber and receiving the scattered light on the in-coming fiber. Light scattered in the transmission fiber is coupled to the incoming fiber in the loop-back couplers in each amplifier pair in a repeater.
27. Repeater Repeater Repeater Repeater HLLB HLLB HLLB HLLB OTDR Vs COTDR Repeater Light Pulse OTDR HLLB Backscatter OTDR can only measure up-to first repeater Repeater Light Pulse COTDR HLLB Backscatter OTDR can cross the repeaters & can measure till opposite end terminal
28. COTDR Measurement plot
29. Electrical path Fault Localization Subsea cable Electrical path fault (Shunt Fault) localization is a manual process & no automatic measuring equipment/testers are available. This requires tedious calculations from PFE voltage & cable properties, before & after fault occurs. Below are some of the techniques used for this. Power Feed (output variation/ohms law) – Using the simple ohms law formula for voltage/Impedance calculation, approx. fault location to be calculated. This is called power budget calculation. Total PFE voltage(Segment voltage) = Cable voltage drop + BU drop + Repeater drop + earth resistance PEFL (impedance mismatch) DC Testing (IR, IC and CR) – This is normally done from cable repair ship for checking the cable continuity & post repair checks. Electroding (detection of a magnetic field due to applied tone) from Terminal PFE.
30. Electroding Electroding technique is sending low-frequency AC tone from Terminal PFE, using the capabilities of the PFE coupled & with special detection equipment having low-current dc and low-frequency resistance and capacitance measurements which can be used in repair ship to find out the exact fault. Electroding is used for different purpose. To identify the exact location of fault in a suspected span, either shunt or cable break from ship. To identify & pickup the exact cable system, out of many cables laid on Seabed, during a repair activity from ship. Fault Detected at Tone leakage point X Electroding Signal Low frequency A.C tone 4Hz to 50Hz
31. Subsea Cable repair The damaged Under Sea part of cable is repaired by specially equipped cable ships A number of Cable ships are strategically located in different regions Damaged portion of the cable will be lifted and removed by the cable ship and join again with a new piece of cable The operation will take usually 10-15 days depending upon the distance of cable fault, Nature of the fault, spare availability in the ship and weather conditions.
32. A Shunt Fault Shunt Fault – Single end Feed, Service affecting Shunt Fault – Dual end PFE Feed, Not Service affecting
33. Cable Joints Cable joints connect similar types of cable on land and at sea during initial cable laying & during a repair operation. Sea Cable Joints
34. Sub Marine cable System visual tour Sub Marine cable system Video
35. CABLES AROUND AFRICA ► ►
36. Thank You!