Presentation on

MCD-80 &

NSD-50 BY Ms. SHUBHANGI UNDALE

MCD-80The modular coupling units MCD-80 ,together with the coupling capacitor and line trap basically fulfill the following functions:

Insertion and extraction of PLC signals on high voltage overhead lines and cables.

Through connection and distribution of PLC signal in intermediate stations.

Impedance matching between transmission path and PLC equipment .

Potential separation of high voltage equipment and PLC equipment.

MCD-80 includes :

PLC Coupling filter A9BS

Tunable drain coil and the coupling capacitor together with a tunable series capacitance and shunt inductance form a programmable highpass filter.

Transformer with taps-:Proper matching of the line impedance to the equipment impedance and can be programmed for two values of both line and equipment impedance.

Lighting arrester-:Limits voltage peaks coming from the line to a value harmless for the circuit.

Drain Coil -: It diverts the power frequency current flowing through the coupling capacitor to earth.

Programmable A9BS

High-Pass Coupling Filter A9BS

PLC Coupling filter A9BT-:

A9BS are supplemented by A9BT to provide a 2 phase or inter system coupling.It has built-in hybrid transformer A1AC.

A1AC (Hybrid Transformer) -:Distributes PLC signal in push-pull operation to the 2 phases so that the additional attenuation is not greater than approx. 4 db with single-phase fault close to the station.

A1AE (Impedance Transformer) -:It transforms the nominal Z2=75 unbalanced or 150 balanced.It is required when the high pass coupling filter A9BS/A9BT is used in system fitted with equipment cable of 50 or 150.

High-Pass Coupling Filter A9BTProgrammable, with 1 Additional Module

ABB Pow er S ystem C om m unica tions

P ow er L ine C arrie r E TL Fam ily T ra in ing P rogram

Phase to Phase S ys tem

C C b locks h ig h voltage 50H z po w er

enterin g in to the PLC C term in al

B T & LM U m atches th e

PLC C term in al im pedance to

the line im pedance

Earth C oil, L A are for protection s for leakag e /surg es an d earth sw itch

for m ainten an ce

purp ose

Line trap b lo cks PL C C sign al enterin g in to

sw itch yard equipm ent

P LC C O V E R V IE W

1.Wave Trap :

Its function is to confine the high frequency currents to the out going power line and to block them from the impedance represented by the station transformer and other equipment.

2.Coupling Capacitor :

It itself usually has a capacity between 2000pF and 10000pF. It couples the signal to the PLC coupling devices from HV lines.

3.Protective Device :

It is intended to protect the carrier equipment and its operators against over voltage coming from HV lines.It contain some type of over voltage arrestor or spark gap, some method of bypassing to earth the 50 cycle charging current to earth.This coil offers a low impedance to the power frequency but a very high impedance to the carrier frequency,so that its effect on the transmission and reception of the latter is negligible.

4.Line Matching Unit :

It matches the output impedance of the carrier set (75 ohms or 125 ohms unbalanced or 150 ohms balanced) to that of the overhead line (400 to 600 ohms approximately).

Types of Coupling :

1. Single phase coupling

2.Phase to phase coupling

3.Interface coupling

Single Phase Coupling

HV-lineSubstation

Couplingcapacitors

Tx

Rx

Coupling device MCD 80

Linetrap

Cabinet

PLCequipment

A9BS or A9BT

Phase to Phase Coupling

HV-lineSubstation

Couplingcapacitors

Tx

Rx

CouplingdevicesMCD 80

A9BSor A9BT

A9BT or A9BT

Linetraps

Cabinet

PLCequipment

Elements

Interface Phase Coupling

STATION

A

STATION

B

PROTECTION DEVICE

PROTECTION DEVICE

LMU LMU

PLCC

EQUP.

PLCC

EQUP.

WAVE TRAP

WAVE

TRAPCC CC

NSD-50 :

Tele-protection equipment transmits the tripping signals from the protection equipment to the HV primary system plant in power station and substations.

The full version of the Tele-protection equipment NSD-50 for transmitting 4 tripping commands comprises 3 modules,which are directly inserted into the type ETL power line carrier equipment .

It is suitable for handling the tripping signals in blocking ,permissive and direct transfer tripping schemes.Four commands enable parallel circuit lines to be protected with permissive tripping of the line protection and direct transfer tripping of a compensator or the breaker back-up protection.

Interface 1: - Wetted contact/relay

Interface 2: - Voice frequency => “analog channel” - Digital data => “digital channel”

Interface 1 Interface 2 Interface 2 Interface 1

Protec tionR elay

Teleprotec tionequipm ent

ProtectionR elay

Teleprotec tionequipm ent

T elecom m unication system

ph ys ica llin k

Teleprotection system

Tele-protection Basic System :

P7L

BP

7LA

NSD 50

NSD 50

NSK 5

B5LA Power Supply48 VDC

E5LA/B Tx-FilterP3LB

RF-Hybrid

Channel shelfbasic equipm.

User interface Power shelf Option

Channel 1

Module layout, example

NSD 50

B4L

A D

C-c

onve

rter

O4L

B 4

-wir

ePA

Xin

trf.

P4L

B A

F-c

onve

rter

P4L

C I

F-c

onve

rter

P4L

D R

x-co

nver

ter

P4L

F T

x--R

F-c

onv

.

9R 4R 6R 6R 6R 6R7R 8R 8R 6R4R 10R

G4A

A D

SP

-Mod

ul

G4A

C I

nte

rfa

ce

G4A

E M

ode

m N

SK

5

Pow

er a

mpl

.40

W

P4L

A P

ilot+

Sup

ervn

P

4LG

Car

rier

syn

th.

O4L

AT

elc

ont

rol i

nte

rf.

ETL 41 Single Channel Equipment and 2 Tele-protection commands

INTRODUCTION :

• The full version of Tele-protection equipment NSD50 for transmitting 4

tripping commands comprises three modules , which are directly inserted into the type ETL.

PRINCIPLE OF OPERATION

• The guard signal monitored by the NSD50 is the carrier pilot.

• In the event of operation of protection due to fault, the NSD50 interrupts the guard signal and transmits the protection signal.

DESCRIPTION OF OPERATION• The DSP module hardware consists of a signal processor with the data and program memories,the circuit for input and output of analogue signals,the various input and output units for digital

signals, the auxiliary alarm relay, the clock supply, a serial interface and a watchdog. TYPES OF TRIPPING

1.Permissive Tripping

2.Direct transfer Tripping

1. PERMISSIVE TRIPPING SCHEMES Ensures that all faults can be cleared in the time of the first zone along 100% of the line. The tripping signal from NSD50 is connected in series with a local criterion and tripping can only take place at the receiving end if a tripping signal is being received and local protection relay detects a fault in the direction of the protected line.TRANSMISSION TIME : 12ms(COMMAND PROLONGATION )TRIP EXTENSION :20ms

2. DIRECT TRANSFER TRIPPING The tripping command from the Tele-protection equipment goes directly to the circuit -breaker. Extremely high security and high dependability are therefore more important. The applications for direct transfer tripping are breaker back-up protection, compensator protection and power transformer protection; line protection with direct transfer tripping would be an exception.TRANSMISSION TIME :26ms(COMMAND PROLOGATION)TRIP EXTENSION :100ms

Description of Operation :

NSD-50 comprises a processor PCB type G4AA with the corresponding firmware and either one or two interfaces type G4AA or G4AD. If two interfaces are fitted, 2 uncoded and 2 coded commands can be transmitted.

The relay interface units G4AC and G4AD contain the circuit for communicating with the protection equipment, for monitoring the single component failure condition and for the trip counters.

Possible Device Configurations :

For a single interface module to transmit a permissive uncoded command A (tripping signal a) and a direct transfer command B (tripping signal d).A further possibility is to use a second interface to double command contacts(e.g.where 3

Commands are needed , the fourth contact can be used to duplicate one of the commands).

Comm.A

Comm.B

Un-coded

A/C select

Coded

uncodedB/D select

coded

Comm.C

Comm.D

Un-coded

A/C select

coded

Un-coded

B/D select

coded

Signal a

Signal b

Signal c

Signal d

Relay Interface :

G4AC OR G4AD

DSP-MODULE G4AA

POSSIBLE DEVICE CONFIGURATION

UNCODED SIGNAL

CODED SIGNAL

F1 F2