SURGE ARRESTERS AND SURGE SUPPRESSORS

IN TRANSFORMER

Guided by:-Er. SMRUTI PRAGYAN DALAI & Er. UMESH CHANDRA MISHRA

Submitted by:-Vikas Kumar ManjhiBranch:-ElectricalReg. No:-1201214203Sec:-B

CONTENT

1) Introduction 2) Transformer3) Lightning4) Surge arresters in transformer5) Types of surge arresters6) How do surge arrester protect transformer7) What exactly does a surge arrester do?8) Advantage and disadvantage of surge arrester9) Surge suppressor in transformer10)How does surge suppressor protect

INTRODUCTIONSURGE ARRESTER: A device used on power system in high voltage, to protect

electrical equipments from lightning and switching surge . It is a surge diverter.SURGE SUPPRESSOR: This is also a surge diverter but generally used in low

voltage equipments. It is generally used in electronics equipment.

This paper presents information about the characteristic and design of arresters and suppressors.In addition to applications, it also provides information about the protection of transformer.

Transformer As we all know that, “a transformer is a static device which transfer electrical energy from one circuit to another without change in frequency’’.Transformer are very important and costly apparatus in power system. Factor that can damage transformer 1) Lightning 2) Power frequency

Lightning Lightning is a sudden electro static discharge between two clouds during storm.When lightning strike transmission line then a very high voltage generated with in it.

This high voltage causes failure in the insulation capacity of transformer .

Which result in the bursting of transformer or other electrical device.

We can protect the transformer from lightning by using

1. surge arrester 2. surge suppressor .

Surge arrester in transformer It protect

transformer from lightning and switching surges.

It is also called Surge Protection Device(SPD).

It is also used in power transmission and distribution system.

Types of arresters

Low-voltage surge arresterDistribution arresterDC or blowing valve-type arresterNeutral protection arrester Magnetic blow valve station arrester

How do surge arresters protect transformer or power system

11000 Volts

230 Volts

Typically11000 Volts

230 Volts

Typically11000 Volts

230 Volts

Surge arrester

Typically 11000 Volts

230 Volts

Surge arrester

What exactly does a surge arrester do?It does not absorb the lightning.It does not stop the lightning.It divert the lightning to ground.It limit the voltage produced by

lightning.It only protects equipment

electrically in parallel with it.

At the Heart of all Arresters is the Metal Oxide Varistor (MOV)

The MOV Disk is a semiconductor that is sensitive to voltage .

At normal voltage the MOV Disk is an insulator and will not conduct current.But at higher voltage caused by lightning it becomes a conductor.

The Metal Oxide Varistor (MOV) is a very fast acting electronic switch.

It is an open switch to standard system AC voltage and a closed switch to Lightning voltages.

Advantage of surge arrester in transformer

The surge arrester protects the transformer.

The surge arrester alerts operator, when it is damaged.

The surge arrester can be changed live line.

A healthy arrester is present at all times.

Disadvantage of surge arresterConducting surge arrester blow fuses.Surge arrester has no live line

capabilities.Unsafe maintenance of surge arrester.

Surge suppressors in transformerSurge suppressor (surge protector) is a

device to protect electrical devices from surge voltage.

It is also known as transient voltage surge suppressor (TVSS).

This is also a surge diverter but used in low voltage equipments.

It is generally used in electronics equipment

How does surge suppressor protect?Blocking unwanted voltage or current. Shorting to the ground.

What is surge voltage?High amplitude Short duration over voltage.

Reference:- Sites:-www.electrical4u.comwww.thefreedictionary.comwww.wikipedia.comBooksV Kamaraju(High Voltage Engineering)