Comm System for TT06 Final

Institut Latihan Sultan Ahmad Shah(ILSAS)

Unit Operasi Penghantaran - April 2004

KURSUS LATIHAN KEKOMPETENAN

Unit PerlindunganSeksyen Latihan Penghantaran

Institut Latihan Sultan Ahmad Shah (ILSAS)

PERLINDUNGAN PENGHANTARAN(SETAKAT 132kV)


Unit Operasi Penghantaran - April 20041 April 2010 2

ICT DIVISIONTENAGA NASIONAL BERHAD

Basic TELECOMMUNICATIONS

SYSTEM



Overview• Role of Telecommunication Dept.• Basic Telecommunications System• Analog System - Power Line Carrier

System• Digital Transmission Equipment



Role of Telecommunication Section

Provide secure teleprotection signaling channels for intertripping functions

Provide reliable data (RTU, SCADA. Etc) network.

Provide internal voice network.Plan, design and implement TNB’s private

telecommunication network for operational and administrative purposes



BASIC TELECOMMUNICATIONS

SYSTEM



Telecommunications

The greek ‘tele’ prefix means distant, and nothing else.

Communication, is defined as ‘ the imparting, conveyance or exchange of ideas, knowledge or information. It might be done by word, image, instruction, motion, smell - or maybe just a wink.

Telecommunication - distant communication - is communication by electrical, radio or optical (e.g. laser) means.



Telecommunications SystemsThere are four essential for effective telecommunications between two points:

• a transmitting device

• a transport mechanism

• a receiving device

• the fourth requirement is that the conveyed information is coded in such a way as to compatible with, and comprehensible to, the receiver.



Common Types of Communications SystemsIn order to meet differing telecommunications needs, a number of different types of telecommunications equipment have been developed over time. These include, in chronological order:

• telegraph

• data networks using either circuit-, packet-, frame-, or cell-switched conveyance

• telex

• integrated voice and data networks

• telephone

• computer LANs, MANs, and WANs.

• Multimedia networks



TRANSMISSIONMEDIUM



Media Use•Copper wire Very common, especially by telephone

companies•Coaxial cable Increasing common, especially by

computer network

•Microwave radio Common in high traffic area, especially where terrain is difficult for cable laying

•Satellite Common for general application

•Fibre optic Increasingly common in high density area, especially long unbroken lines



ANALOG TRANSMISSION SYSTEM

POWER LINE CARRIER(PLC)



power transmission line



Then, why power line?

• already exist, so relatively cheap

• own, manage and supervise by TNB

• readily available (e.g. for remote station)



PLC - BASIC CONFIGURATION`

Line Trap

CVT (Capacitor Voltage Transformer)

LMU (Line Matching Unit)

HF Cable

PLC Equipment

S/S

Transmission Line



Line trap - on pedestal



Line Trap(hanging type)



Line trap

CVT

Incoming (from end station)

Outgoing



Earthing Switch

Lightning arrester

Matching transformer

Combination transformer

Filter

HF Cable

Line Matching Unit



HIGH FREQUENCY (HF) CABLE

•Inserted between the LMU and PLC equipment

•Normally a pair cable of 140-150 ohms is used



PLC - CONFIGURATION

PLC Equipment

LMU

CVT

Line Trap Line Trap

S/S A S/S B

PLC Equipment

Transmissionline

HF Cable


Unit Operasi Penghantaran - April 20041 April 2010 21PLC Equipment



PLC Equipment



SERVICES



Speech channel is mainly used for operational purposes. PAXs are installed at various strategic PMUs and power stations all over peninsular. Extension to remote stations are carried out through various telecommunications medium.

Speech Communication



Data Communication

Data channel is mainly used for SAS, SCADA communication between NLDC and the remote terminal unit (RTU). Other application include administrative channel, remote metering LAN & WAN, tie-line monitoring and Remote Alarm Monitoring System (RAMS)



The two most important application of teleprotection channels are:

Teleprotection

b) direct tripping of circuit breaker from protection devices at the other end of the line

a) transfer of discrete information from protection relays at one end of the line to those at the other end



FACTS

• PLC network has reached the limit of expansion and cannot provide quality channel required for prevailing services

• PLC communication uses analog transmission technology which is already superseded by digital transmission technology

• Digitalization of communication network offer a lot ofadvantages in term of capacity, speed, reliability andsecurity



DIGITAL TELECOMMUNICATION

NETWORK



Why Digital System?• An analog system is susceptible to changes in amplitude, frequency and phase. A digital signal is immune to noise.

• A digital network is possible to interwork with different transmission rates and the network is capable of carrying many type of services.

• Digital transmission system do not encounter intermodulation as in analog system.

• Digital transmission gives tremendous advantages in terms of operation and maintenance.



SATELLITE

The system requires the setting up of earth station at

major stations along the trunk route of the network.

To acquire lease channel from satellite operator.



SATELLITE

Constraint:- cost per channel is high- not suitable for time crucial function

(e.g teleprotection) as the time delayis very high

- future expansion is also limited.



MICROWAVE RADIO

an attractive solution for provision oftrunk links to important stations in

the network.



MICROWAVE RADIOConstraint:

• permission to operate, license, operating frequency etc

• acquisition of suitable as well asaccessible sites for the repeater station (long distance communication)



MICROWAVE RADIOConstraint (Contd.) :

• Security and staff for manning the station. High maintenance cost.

• Required suitable area for line-of-sight communication.



OPTICAL FIBREThe most attractive solution for TNB’s requirement

for more reliable telecommunication system.

Cost effective fibre optic network can be established using existing and new transmission

line configuration



Advantages of Optical Fiber as a telecommunication media

• Low loss ~0.2dB/km• High Bandwidth - up to 10Gbit/s• No signal interference : emi, rfi (induction,

cross-talk)• Light weight, thin & flexible cables• Fire and shock safe?• Low cost



Type of Optical Fiber Cable• Wrap around (Sky wrap)

– The Optical Fiber cable is wrapped around the ground wire

• ADSS– All dielectric self supporting

• OPGW– Optical ground wire

• Submarine• Underground



Type of Optical Fiber Cable

OPGW

Wrap Around

ADSS

Approach cable

Joint-box



SPACER TYPE STAINLESS TUBE TYPE

Fiber UnitAluminum Unit

Aluminum Spacer

Aluminum Clad Steel

Aluminum Alloy

LOOSE TUBE TYPE

Fiber UnitAluminum Pipe

Aluminum Alloy

Stainless tube

Steel

STRUCTURE OF OPGW



STRUCTURE OF ADSS

All-Dielectric Self-Supporting Loose Tube Cable

Polyethyleneouter sheath

Polyethyleneinner sheath

Buffer Tube

Aramid yarn

Flooding/fillingcompoundsOptical fiber

Dielectric central member



Optical Fiber Cable(Step index fiber)

Jacket

Cladding

Core

Glass or plastic coreSpecially designed jacket

travelling light



Digital Transmission Equipment

• Equipment to transmit signal digitally

• The PCM signals need to be transmitted over very long distance (more than 100 km).

• The conversion, multiplexing and transmission is done by the digital transmission equipment

• For efficient transmission, many signals are multiplexed before transmission.



Hierarchy in Digital Transmission System



HIERARCHY IN DIGITAL TRANSMISSION SYSTEM

ITU-T (CCITT) has specified two hierarchical system to be used in digital transmission

system. They are the plesiochronous digital hierarchy (PDH) and synchronous digital

hierarchy (SDH)



PDH Higher Order Systems

• The 30-channel (32 time slots) system is not suitable for transmission over long distance network. It is mainly used in urban networks using existing pair cables.

• In long distance networks a much higher capacity is usually used. For this purpose the use of hierarchy system in PCM transmission has been specified. This will increase the number of channels and subsequently, increasing the bit rate.



PDH - Plesiochronous Digital Hierarchy

Higher Order Multiplexer

2 8 MUX 34

MUX 140 MUX

30

PMUX

30 * 4 = 120 ch120 * 4 = 480 ch



LevelNumber

(Hierarchy)

System Number ofchannels

Bit rate(Mbps)

1 M1 30 2.048

2 M2 120 8.448

3 M3 480 34.368

4 M4 1920 139.264

5 M5 7680 565.154



Limitation of Plesiochronous Digital HierarchyThere are two main limitations of the PDH:

• The inability to identify individual channel in a high speed bit stream. In order to access a single 2 Mbit/s line the 140 Mbit/s structure must be completely demultiplexed down to its 64 constituent 2 Mbit/s lines via 34 and 8 Mbit/s. Once the required 2Mbit/s line has been identified and extracted, the remaining 2 Mbit/s lines must then be re-multiplexed back up to 140 Mbit/s.

• Lack of performance monitoring capability. The PDH frame format has insufficient provision for network management.

• A lot of Network Element and too many interconnections.



SDH - Synchronous Digital Hierarchy

• network management capability within the hierarchy

• overcome the inability of the PDH to extract individual circuit from high capacity systems without

having to demultiplex the whole system

• define standard interfaces between equipment

• facilitate internetworking between North American and European transmission hierarchy.



SDH - Synchronous Digital Hierarchy

STM-4 STM-1 STM-1 STM-4

2 Mbit/s

STM-1 155Mbit/sSTM-4 622Mbit/sSTM-16 2488Mbit/s



PDH SDH

• Stage by stage MUX andDEMUX

• Single stage MUX andDEMUX

• Proprietary optical format • Standard optical format

• No master clock to controlon higher transmission

• Master clock to control

• Limited managementfeatures

• More management features

• High capacity only on140Mbps

• High capacity up to 10Gbps(STM 64)

• Three hierarchy (ANCI,CEPT and Japan)

• Unified interface



Teleprotection Channel



Teleprotection Signaling for Distance Protection

1. Teleprotection signaling is used together with some types of relays, for example Distance Relay.

2. Teleprotection signaling for DP can be provided either through analog transmission equipment (e.g. PLC) or digital transmission equipment (e.g. PDH)

3. Service with DP relay can be configured to provide 3 types of protection schemes namely BLOCKING, PERMISSIVE UNDERREACH and DIRECT INTERTRIPPING.

4. Teleprotection signaling can be simple on/off channel, frequency shift channel, a combination of on/off and frequency shift channel, coded system (PLC) or more advanced system through digital equipment.



Teleprotection Signaling for Distance Protection Scheme

Comm. Transmitter

Comm. Receiver

Relay (Tx.) Relay (Rx.)

110VV

TPE TPE



Zone 1 for Relay A

Zone 1 for Relay B

A fault at D causes distance relays at A and B to trip circuit breaker at A and B simultaneously and instantaneously..

Distance Protection Permissive Underreach

CircuitBreaker

CircuitBreaker

Distance relay

Distance relay

Decision Decision

A BD



Zone 1 for Relay A

A fault at C causes distance relay at A to trip circuit breaker at A

The fault is outside zone 1 of B which enter ‘delayed command’ without tripping breaker

During this period, equipment may be damaged and synchronism is lost

Without Teleprotection Signaling

Zone 1 for Relay B

CircuitBreaker

CircuitBreaker

Distance relay

Distance relay

Decision Decision

A BC



Zone 1 for Relay A

Zone 1 for Relay B

CircuitBreaker

CircuitBreaker

Distance relay

Distance relay

Decision DecisionTele-protection

Tele-protection

AC

B

With Teleprotection Signaling

A fault at C causes distance relay at A to trip circuit breaker at A

The fault outside Zone 1 at B which enters ‘delayed command’ without tripping breaker

But, the permissive command arrives immediately at B which can trip the breaker



Teleprotection Channel for Current Differential Scheme

• Require high speed data transmission channel, so only works with digital transmission equipment

• Dedicated data channel for continuous communications between two relays.

• 64 kbps data channel with G.703 data interface

• Connected using Screened Twisted Pair cable



TELECOMMUNICATION FOR TNBSafe, reliable and economical energy supply is closely related to fast, efficient and reliable

telecommunication network.

New development in operation, supervisory and protection function demands faster and more

efficient telecommunication system

Jabatan Telekomunikasi, ICT to continuously upgrading and strengthening TNB private

telecommunication network.



Terima kasih atas perhatian anda semua.

Tay Teck Kheng

Jabatan Telekomunikasi, ICT

019-2268308

Comm System for TT06 Final

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