electrical protection by mmy

8/3/2019 Electrical Protection By MMY

1/97

Electrical Protection

By: Eng.Mahmoud Mostafa Aiad- S.O.P.C


2/97

Course components:

:


3/97

:

.1Normal:()

.

.2Fault:.

.3Relay:

(Abnormal).

.4Contact)Open(NormallyNOC:

.

.5Contact)Closed(NormallyNOC:

. .6RelaysPrimary

:

.

.7RelaysSecondary:

.

.8RelaysElectromagnetic:

.

.9Static Relays:

(Slave devices)

.

.10Main relays:

.

.11Backup Relays

:

.


4/97

:

.12Selectivity:

.

.13Sensitivity:

.

.14timeOperating:

.

.15RelayInstantaneous:.

.16relaydelayTime:.

.17relayscurrentOver:

.

.18RelayTimeDefinite:.

.19relayTimeInverse:

(I.T=K).


5/97


6/97

FrequencyCurrentVoltage

FrequencyCurrent

V I F


7/97

:

FrequencyCurrentVolt FrequencyCurrent

Under Voltage

Over Voltage

Phase Sequence

Phase losses

Surge voltage

Under Current

Over Current

Short circuit

Earth fault

Current Direction

Un balance current

Under Frequency

Over Frequency

Harmonic frequencies


8/97

:

Elements to be Protected:


9/97

Protection system components:

:

Protection System

Sense

Interface

Action

PT CTPT CT


10/97


11/97

:

:

.

.

.

.

.

Purpose of Protection System:


12/97

:

P.T, C.T .

Relays.

Fuses.Circuit Breaker

.

Surge Arrestor .


13/97

C.T & P.T


14/97

(C.T, P.T:)

2) Current Transformer (CT)1) Potential Transformer (PT)

Voltage Ratio ErrorClass

Measurement

0.1%0.1

0.2%0.2

0.5%0.5

1.0%1

3%3

Protective

3%3P

6%6P

Current Ratio ErrorClass

0.1%0.1

0.2%0.2

0.5%0.5

1.0%1

3%3

5%5

1%5P

3%10P


15/97

Potential Transformer (P.T):

:

1-

.

U.V relay

O.V. -2 .

3-

Voltage Transducer

4-20 mA DCS.

:


16/97

P.T types:

-:

-:

1) TransformerElectromagnetic Voltage

66.

Capacitor Voltage Transformer (2

66

(8)

:-

C2 -1 C1 . . ((reactor -2

P.Tintermediate -3

.

:


17/97

Capacitor voltage Transformer:

:


18/97

How to choose P.T?

:-

-:

Rated Transformation Ratio-1

.

s

pn

V

VK

:


19/97

Ratio Error or Voltage Error -:2

=Kn

=V

p

=Vs

3:- Accuracy Class

((3

.

(4)

.

%p

ssnE

V

VVKR

How to choose P.T?

:


20/97

(VA)burden -:4

VA

Voltage Error- Ratio Error

.

(5)

VA

VA .

VA25 - 35 - 45 80-100 .

How to choose P.T?

:


21/97

VA

VAEquipment

5 VAVoltmeter

5 VAVoltage coil of wattmeter

7.5 VAVoltage coil of KWH meter

15 VAVoltage coil of synchroscope

5 VAUnder/Over voltage Relay

3-10 VAVoltage coil of electromagnetic relay0.02-0.2 VAStatic relays


22/97

3Un/Insulation Voltage -5

Un Over Voltage

:-

-1

Un/3

-2

Um

100-110 V

Impulse Voltage

2 KV .

.

.13

5.2 KvUn

Um

How to choose P.T?

:


23/97

:

(2PT) connection (3 PT) connection

Potential Transformer Connection:


24/97

Current Transformer:

:

.1

()

5A & 1A

.

2..

3.

5A & 1ACurrent Transducer

(4-20 mA)

DCS.


25/97

Shapes of Current Transformer:

:


26/97

Current Transformer construction:

:

:

(cast resin)

( cast resin bar primary current transformer ) :-

. -1 -2

. -3

.. -4

(1)

:-

1- .( Double Terminal)

.

2- (Primary winding).

.


27/97

( ( cast resin body -3

. 4- (soft magnetic core)

.

5- (secondary winding)

15

Ith6-

( Earthing screw of secondary)

S1

.7-

(secondary terminal)

Current Transformer construction:

:


28/97


29/97

:

:-

:-Rated Transformations Ratio

(Name Plate).

.

=Isec.

=Ipr.

=K

.sec

.

I

IKn

pr

How to choose a C.T?


30/97

:Ratio Error 3-2

(actual value) .

:

1- .

(short circuit) -2 .

3-3-

:Composite Error

(KnIsec.-Ipr.)(One Cycle)

Steady Condition

. r.m.s

2.5-5-7.5-10-15-30-40-VA

dtIIK

I

rrorCompositeE prnpr

)(100

.sec.

:



31/97

3-4:- -Accuracy Class :

.

5P10

.

(3)

Class Curves

. -:3-5

(VA)Rated burden

VA

.

.

burden

((1

VA

.

.

((2

VA 10.

:



32/97

-:Insulation Voltage -:3-6

(/3)

Um

Over voltage.

:-

1-

Un/3. -2

Um.

Impulse Volt

2KV

.

.13

*5.2 KvU

Un

n

:



33/97

-:3-7Rated Thermal Current

r.m.s

(Short Circuited)

.

:-

1- .

2- ( . )

.

)Ith ) = 180 * S

)Ith ) = 118 * S

=S

:-

=Ith

t=Ith,t

T

II

thth t ,

:



34/97

:


-:3-8

:-dynIRated dynamic Current

r.m.s

(Short Circuited)

:-

Idyn = 2.5 Ith .

Idyn Ith

.


35/97

C.T Curve:


36/97

:


37/97

Current Transformer Connection:

:


38/97


39/97

:

:Relays


40/97

. :

- (

.)

- .

-

.

- .

Relays::


41/97

: 1. Electromagnetic relays

{EMRs consist of an input coil that's wound to accept a particular voltage signal,plus a set of one or more contacts that rely on an armature (or lever) activated bythe energized coil to open or close an electrical circuit}.

2. Solid-State Relays{SSRs use semiconductor output instead of mechanical contacts to switch thecircuit. The output device is optically-coupled to an LED light source inside therelay. The relay is turned on by energizing this LED, usually with low-voltage DCpower}.

3. Micro Processor Based Relays

{Use microprocessor for switching mechanism. Commonly used in power systemmonitoring and protection}.

Relays:

:


42/97

: .1

(Thermal relays.)

2. (Electromagnetic Attracted - Relays.)

3. (Electromagnetic Induction Relays.)

.4 (Static Relays.)

Relays:

:


43/97

Relays:

:


44/97


45/97

Induction type relay

Relays:

:


46/97

Fuses:

:

:

( )

:Fuse)

( ) (

.)

.

()

.

( .)

()

.

(

cutout fuse.)
http://www.arab-eng.org/wiki/%D9%84%D8%BA%D8%A9_%D8%A5%D9%86%D8%AC%D9%84%D9%8A%D8%B2%D9%8A%D8%A9http://www.arab-eng.org/wiki/%D9%83%D9%87%D8%B1%D8%A8%D8%A7%D8%A1http://www.arab-eng.org/w/index.php?title=%D8%A5%D9%84%D9%83%D8%AA%D8%B1%D9%88%D9%86%D9%8A%D9%83&action=edit&redlink=1http://www.arab-eng.org/wiki/%D8%AA%D9%8A%D8%A7%D8%B1_%D9%83%D9%87%D8%B1%D8%A8%D8%A7%D8%A6%D9%8Ahttp://www.arab-eng.org/wiki/%D8%AA%D9%8A%D8%A7%D8%B1_%D9%83%D9%87%D8%B1%D8%A8%D8%A7%D8%A6%D9%8Ahttp://www.arab-eng.org/wiki/%D8%AF%D8%A7%D8%A6%D8%B1%D8%A9_%D9%82%D8%B5%D8%B1http://www.arab-eng.org/w/index.php?title=%D8%AD%D9%85%D9%88%D9%84%D8%A9_%D8%B2%D8%A7%D8%A6%D8%AF%D8%A9&action=edit&redlink=1http://www.arab-eng.org/w/index.php?title=%D8%A7%D9%84%D8%AD%D9%85%D8%A7%D9%8A%D8%A9_%D8%A7%D9%84%D9%83%D9%87%D8%B1%D8%A8%D8%A7%D8%A6%D9%8A%D8%A9&action=edit&redlink=1http://www.arab-eng.org/w/index.php?title=%D8%A7%D9%84%D8%AD%D9%85%D8%A7%D9%8A%D8%A9_%D8%A7%D9%84%D9%83%D9%87%D8%B1%D8%A8%D8%A7%D8%A6%D9%8A%D8%A9&action=edit&redlink=1http://www.arab-eng.org/w/index.php?title=%D8%AD%D9%85%D9%88%D9%84%D8%A9_%D8%B2%D8%A7%D8%A6%D8%AF%D8%A9&action=edit&redlink=1http://www.arab-eng.org/wiki/%D8%AF%D8%A7%D8%A6%D8%B1%D8%A9_%D9%82%D8%B5%D8%B1http://www.arab-eng.org/wiki/%D8%AA%D9%8A%D8%A7%D8%B1_%D9%83%D9%87%D8%B1%D8%A8%D8%A7%D8%A6%D9%8Ahttp://www.arab-eng.org/wiki/%D8%AA%D9%8A%D8%A7%D8%B1_%D9%83%D9%87%D8%B1%D8%A8%D8%A7%D8%A6%D9%8Ahttp://www.arab-eng.org/w/index.php?title=%D8%A5%D9%84%D9%83%D8%AA%D8%B1%D9%88%D9%86%D9%8A%D9%83&action=edit&redlink=1http://www.arab-eng.org/wiki/%D9%83%D9%87%D8%B1%D8%A8%D8%A7%D8%A1http://www.arab-eng.org/wiki/%D9%84%D8%BA%D8%A9_%D8%A5%D9%86%D8%AC%D9%84%D9%8A%D8%B2%D9%8A%D8%A9


47/97

Fuses:

:

:

() .

(weak point)

.

(1920)

M)(1930))

.

(1940).

IEC 60269


48/97

Fuses:

:IEC 60269

(1950)

.

(/

).

.

.

.

.

:


49/97

Fuses:

:

:((Fuse

:

.

:

2015

.

.:

.

110%

(Transient Recovery Voltage)

.

Capacity)(Interruption:

.

:


50/97

Fuses:

:

:Fuse holder -1Fuse base -2Fuse carrier -3Fuse link -4

.

.

::((Fuse Link

Cartridge

arc-extinguishing

.

.

Fuse link.

element.

.


51/97


52/97


53/97

:


54/97

Fuses:

:

-(Rating Current):

Fuse link.

element.

-(:(minimum fusing current

Fuse element

.

asymptotic/

.

:((Fusing factor -

: =

:( ( Prearcing time -

.

:( ( arcing time -.


55/97

:((Fuse operation time-/)

)

.

:

+=-

(Prospective Current):

(/

).

.(:(virtual time -

(). steady current

:

i.dt / Iptv =


56/97

: 1.

.

2.

.

3. (recovery voltage. )

.4

.

.5

.

.


57/97

: .1

5%

fusing factor(1.75)

(1.25).

.((1.252.

.

3.

.

4..5.

.


58/97

: -

:

(:(Power Filled Fuses .1

.

( :(Miniature Fuses .2

. 3. (Semi-enclosed Fuses:)

.4(Expulsion Fuses):

:((Power Fuses.5

.Liquid quenched fuses .6(Distribution Break Fuses):

.


59/97

- :.660 .1.660 .2-

:

.1 (Non-Current Limiting Fuses).

.

: .((Expulsion Fuses -.((Vacuum Fuses -

.2 (Current Limiting Fuses).


60/97

(:(Expulsion Fuses -

. .

(K5000-4000)

. .

Pole-Mounted Transformers 3000 .

.

.


61/97

(:(Vacuum Fuses -

.

.

.


62/97

.2 (Current Limiting Fuses:)

Prospective Peak Current (1.) (ID)

Cut-Off Current

.

.

(.(It

.

(High Rupturing Capacity HRC-

Fuses).

(

. )

.


63/97

: -

over load

short circuit

.

weak point

.

(4)

(4-)

Tin wire( fuse

link) .

. )-(4

semi enclosed rewirable fuses

.

(4-) insert open tube(4-)

.


64/97

(-(4(Domestic (D) Type (D (-(5NH

miniature fuse

link semi conductor fuse links.(:(Fuses Design -

.

fuse element

.

:

.


65/97

: -1Powder filled cartridge fuses

Powder quartz Silicon oxide (Si O2 .(

iron compounds

organic matter .

(5) Sand filled cartridge fuse

(100) .

:

()

Closing

angle.

Cut-Off current

(5000) =17300 Amp]([2)2x5000

.


66/97

(1000).

. (5000)

.

((It Joule integral

(It.)

Constriction

.

Pre-arcing time

. .

. element .

filler ( )

. .

.tape wire


67/97

Constriction( ) .

(6)

.

(1) (M)M-effect

(2)

.

(1)

.

(5) Dual element time lag.

Uniform element.

. :

(.(It


68/97

Small over current .

.

.

(M)M-effect .

Low melting point alloy

. .

:

-

.

.

Constricted points

(It)

.

.

.


69/97

:

:

. .

.

:

(.)..

Negative sequence current

.

.

.


70/97

:

: .1

(Short circuit.) 2.

(.(Over Load (.(Locked Rotor 3.(.(Unbalanced Power Supply 4.(.(Under Voltage 5. 6.

(Under Current.)

.7 (Phase Reversal.)

.8 (Over current.)


71/97

Power Transformer Protection:


72/97

:

: .1

(Short circuit.)

. 2.

Power Transformer Protection:

1 Earth Fault protection:


73/97

1-Earth Fault protection:

( .)

Y:

.

:

Y.

1. :

2 Differential Protection:


74/97

2.Differential Protection:

2.

:

Differential protection of a Delta/Star transformer

2 Differential Protection:


75/97

(

)

()

.

2.Differential Protection:

2.

:

3 Buchloz Relay:


76/97

3.Buchloz Relay::.3

.

..

.

What make Buchloz relay Works?


77/97

What make Buchloz relay Works?

:

(

)

.

.

.

.

.

.

Buchloz Relay


78/97

Buchloz Relay


79/97

Location of the Buchholz relay on the transformer


80/97

Location of the Buchholz relay on the transformer


81/97

4 Di l t t t th t


82/97

4. Dial-type contact thermometer

.

.

.

(

).

4 Di l t t t th t


83/97

4. Dial-type contact thermometer

5. Winding Temperature Indicator


84/97

g p

.5

6. Magnetic oil-level indicator


85/97

g

.

(limit position switch) .

.

6.

7. Magnetic oil-level indicator


86/97

7. Magnetic oil level indicator

7.

8. Pressure relief


87/97

8 essu e e e

Pressure Relief During Fault Pressure Relief Before FaultOccurrence

Pressure Relief During Fault Pressure Relief Before FaultOccurrence

.8

. Dehydrating Breather9


88/97

.9

.

.

.

y g

. Dehydrating Breather9


89/97

.9

y g

Generator Protection:


90/97

:

.1

(Differential protection.)87G

.2 (Ground Fault for stator.)51G,64

.3 (Ground Fault for Rotor.)58

4.(Power Reverse.)32

5.

(Over Current.)51 V

6.(Under frequency.)81

7.(Over frequency.)81

8.(Over Voltage.)59

9.(Under voltage.)27

Generator Protection:


91/97

10.(Unbalanced Load.)

11.(Winding Temperature).26

(Loss of Excitation.)40 12.

13.(Over Excitation.)24

14.(Over Load RTD.)49R

:


92/97

1.

:


93/97

2. :

3. Power Reverse (Anti-Motoring):


94/97

.3:

( g)

4.Under/Over Frequency


95/97

.4/ :

/ q y

4.Under/Over Voltage:


96/97

.4/ :

g


97/97

electrical protection by mmy

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