CONTROL OF SYNCHRONOUS MACHINE

8/11/2019 CONTROL OF SYNCHRONOUS MACHINE

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CONTROL OF SYNCHRONOUS MACHINE

BY USING DIGITAL MOTOR PROTECTION

RELAY

PROJECT TITLE :


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Oxygen gas plays a vital role in steel making process for that

purpose oxygen compressors are used. To drive this compressors11MW/11KV synchronous motors are used. To protect this motors

relays are used.

The protection usually provide for three phase motors, while

generally effective against overload and short circuit conditionsrarely taken in to full account the harmful effects of unbalanced

line currents.

The motor protection relay measure the load current and

unbalanced current independently, and provide accurate protectionagainst thermal damage under all operating condition.

Earlier electro magnetic relays are failed to give complete fault

record and history on protection parameters.

ABSTRACT:


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General Features Of VSP:

VSP is the only shore board integrated steel plant in our

country

VSP is the home for several hurry industry in public

sectors like BHPV, Hindustan shipyard, HPCL etc.

VSP contains the following sections:

Coke oven and coke chemical plant

Sinter plant

Blast furnace

Steel melting shop

Thermal power plant


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Air Separation Plant

In ASP air is compressed to 6.4 Kscg(kg/cm)

This air is pre cooled in air water to 100c

This is air is passed through the main exchanger where it is

cooled to its due point and from the exchangers will be sent to

distillation column which would separate the air in to oxygen

nitrogen and argon.

Not only the gaseous products liquid products such as liquid

oxygen, liquid nitrogen, liquid argon are also produced.

SMS required 99.5% of oxygen for LD converter blowing

64.47% of total nitrogen for blast furnace


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Synchronous Motor

Induction motor have fixed stator winding that are electricallyconnected to AC power

In case of synchronous motor have fixed stator winding

electrically connected to the AC supply with separate source of

excitation

Induction motor can be started by applying AC power to the

stator winding. But synchronous motor required special attention

to start because initially synchronous motor acts as a induction

motor

when the synchronous motor is running at synchronous speed

it is possible to alter the PF by varying the excitation to the rotor

field


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Synchronous motor protection

Figure highlights multiple functions used to monitor thestatus of the synchronous motor.

These devices includes field over and under current, motor

pullout protection and incomplete sequence.

As the synchronous motor builts to rated speed some

maximum time is defined by the manufacture for the excitation

to be applied.


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If motor takes longer than the defined time, rotor squirrel cage

winding will over heat.

Then the relay is set to trip the motor in time to protect thesquirrel cage winding.

The lagging phase angles occurs when insufficient excitation

fails to provide the needed synchronising torque.

The field under current relay monitors for insufficient field

current from the excitation.

Leading and Lagging Current as

Affected by

Field Excitation on the SynchronousMotor


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CTMM Relay

I2 conscious Thermal Protection.

Selectable Thermal CharacteristicsBuilt-in Stalling protection with provision for external

control.

feed with instantaneous or time-delayed operation option

Sensitive earth fault protection suitable for either residual

or CBCT

Features:


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.

Pre-trip alarm with adjustable pick up and time delay with

LED Indication.

. Auxiliary supply supervision with Alarm & LED indication.

Built-in Load IndicatorSuitable for AC or DC Aux. Supplies.

Typical static motor protection relay front facia


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Motor characteristics must be carefully considered whenapplying protection.

The protection usually provided for three phase motors

while generally effective against loads and short circuit

conditions.motor protection relay type CTMM & CTMFM measure

the load current and unbalanced current independently and

provide accurate protection against thermal damage under all

operating conditions.

APPLICATION OF CTMM RELAY:


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DIGITAL MOTOR PROTECTION RELAY

MICOM P220 TYPE

FEATURES:

Digital motor protection relay has continuous range.

It has a possibility of recording of fault.

It can give the complete protection.

It has also external features.

It has a time delay function.

The motor protection relay range is designed for motorprotection application .

A complete set of protection function is performed on

the measurement of current ,voltage and temperature.

On top of that high inertia loads and anti- backspin

protection ensures that the rotor stops the motor can be re

started


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FUNCTIONAL DIAGRAM

Protection function is autonomous and can be individually

configured or disables to suit a particular application


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Protection functions

Short-circuit (50/51)

Earth fault (50N/51N)

second motor protection modemotor(48/49/49LR50S/66)

CB failure (50BF)

Limitation of the number of starts, timbetweenstarts(66)

Loss of load (37)

Unbalance, loss of phase and single phasing (46)

Thermal overload (49)-true RMS value

Locked rotor while running or at start-up (51s)


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CONTROL FUNCTIONS

Independent protection setting groups

Programmable scheme logic

Trip circuit super vision

CB monitoring

External trips

Shape of start up current and voltage

Analog outputs

Trip cause statistics


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Measurement and recording facilities

The relay constantly measures a large amount of electrical data suchas

Phase current magnitude in true R.M.S value :IA,IB,IC.

Neutral current magnitude in true RMS value IN.

Positive sequence current I1, negative sequence current I2, zero

sequence current I0& unbalance ratio I1/I2

Frequency, peak current value, phase to phase voltage true RMS

value, active & Reactive power W&VAR., Active &Reactiveenergies Wh & VARh and power factor.


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User interface

Front plate and menus

Dedicated and programmable LEDs

Local and remote communication

Software support

MiCOM S1 Software makes it possible to pre-set all MiCOM

P220 relay parameters from a PC. The relay is then accessed via the

RS232 port on the front panel.


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Complete configuration of the micomp220

It can be completely configured either by using interface or

by using the control and setting software MICOM S1.

Thermal overload

Short circuit

Earth fault

Unbalance

Excess long start

Blocked rotor

Loss of load

RTD (optional)


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Protection functions

Thermal replica

Thermal current threshold

Over load time constant TE1

Short circuit protection

Unbalance protection

Too long start up protection

Locked raptor protection

Under current protection

RTD temperature detection or thermostats


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AUTOMATION FUNCTIONS

Limitation of the number of start- ups

Time between 2 start-ups

Logic inputs /auxiliary timers

Logic equations time delay

Auxiliary output relay

Latching of the output relays

Trip output relay

Control and monitoring of the breaker device

Optional functions


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Recording functionsEvent recorder

Fault recorder

Inputs and outputs

Phase current IIN 1 and 5 amp

Earth current Ion

1 and 5 amp

Frequency range 45 to 65 Hz

nominal 50/60Hz

Burdens phase current inputs


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THERMAL OVERLOAD

CHARECTERISTICS


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CONFIGURATION OF THE RELAY AND PC

Once the physical connection is established, the relay and pc

settings must be checked in order to start the communication.

HUMAN MACHINE INTERFACE


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HUMAN MACHINE INTERFACE

OUTPUT PARAMETERS

PASSWORD=****

TYPE=P220

REFERENCE=XXXX

SOFTWARE VFR=3CFREQUENCY =50 Hz

ACTIVE GROUP=1

INPUT ST=00000OUTPUT ST=0000

DATE,TIME.


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CONCLUSION:

The motor protection relay range particularly adopted to oil

refinery glass and cement manufacturing paper mills and mining

etc.

so the P220 relay can nevertheless be used as a multi function

relay to protect a high power synchronous motor.

Digital motor protection relay has got very handsomecomputing power, as it incorporates a microprocessor with it.

Present digital relays give all the protection features of old

electro mechanical or static relays. In addition it gives

communication facia supervision and add trouble shootingfeatures on it.

so it has become versatile productive cum human machine

interface module.

CONTROL OF SYNCHRONOUS MACHINE

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