Saturday, September 17, 2011

IEC CODES

1.IEC 60027 Letter symbols to be used in electrical technology...
4.IEC 60044 Instrument transformers
7.IEC 60063 Preferred number series for resistors and capacitors
8.IEC 60065 Audio, video and similar electronic apparatus - Safety requirements
9.IEC 60068 Environmental Testing
10.IEC 60071 Insulation Co-ordination
11.IEC 60073 Basic Safety principles for man-machine interface, marking and identification
14.IEC 60085 Electrical insulation
16.IEC 60099 Surge arresters
17.IEC 60134 Absolute maximum and design ratings of tube and semiconductor devices
18.IEC 60137 Bushings for alternating voltages above 1000V
19.IEC 60146 Semiconductor Converters
20.IEC 60169 Radio-frequency connectors
21.IEC 60183 Guide to the selection of high voltage cables
22.IEC 60204 Safety of machinery
23.IEC 60214 On-load tap changers
25.IEC 60233 Tests on Hollow Insulators for use in Electrical Equipment
26.IEC 60238 Edison screw lampholders
27.IEC 60245 Rubber-Insulated Cables
28.IEC 60255 Electrical Relays
29.IEC 60268 Sound system equipment
30.IEC 60269 Low voltage fuses
31.IEC 60270 High-Voltage Test Techniques - Partial Discharge Measurements
32.IEC 60287 Calculation of permissible current in cables at steady state rating
33.IEC 60092-350 Shipboard Power cables-General construction and Test Requirements
34. IEC 60296 Mineral Insulating oils for transformers & switchgear
35.IEC 60298 high voltage switchgear in metallic enclosure
37.IEC 60317 Specifications for particular types of winding wires
39.IEC 60331 Tests for Electric Cables under Fire Conditions
42.IEC 60417 Graphical symbols for use on equipment
43. IEC 60439 Low voltage switchgear and controlgear assemblies
44.IEC 60445 Basic and safety principles for man-machine interface
45. IEC 60446 Wiring colours
46.IEC 60479 Effects of current on human beings and livestock
47.IEC 60502 Power cables with extruded insulation and their accessories for rated voltages from 1KV up to 30KV
50.IEC 60529 Degrees of protection provided by enclosures (IP Code)
51.IEC 60598 Luminaires
52. IEC 60559 Binary floating-point arithmetic for microprocessor systems
54.IEC 60603 Connectors for frequencies below 3 MHz for use with printed boards
55.IEC 60617 Graphical symbols for diagrams IEC 60651 Sound level meters
56.IEC 60694 Common Specifications For High-Voltage Switchgear and Controlgear Standards
57.IEC 60715 Dimensions of low-voltage switchgear and controlgear. Standardised mounting on rails for mechanical support of electrical devices in switchgear and controlgear installations.
58.IEC 60721 Classification of environmental conditions IEC 60726 Dry type power
transformers IEC 60747 Semiconductor devices; Part 1: General
59.IEC 60748 Semiconductor devices - integrated circuits
60.IEC 60774 VHS/S-VHS video tape cassette system
62.IEC 60801(part 3) EMI and RFI Immunity
63.IEC 60812 International Standard on Fault Mode and Effects Analysis
64.IEC 60815 Selection and dimensioning of high-voltage insulators intended for use in polluted conditions
65.IEC 60874 Connectors for optical fibres
66.IEC 60884 Plugs and socket-outlets for household and similar purposes
68.IEC 60906 IEC system of plugs and socket-outlets for household and similar purposes
69.IEC 60908 Compact disk digital audio system
70.IEC 60921 Ballasts for tubular fluorescent lamps - Performance requirements
71.IEC 60929 AC-supplied electronic ballasts for tubular fluorescent lamps - Performance requirements
72.IEC 60947 Standards for low-voltage switch gear and controlgear
73.IEC 60950 Safety of information technology equipment
74.IEC 61000 Electromagnetic compatibility (EMC)
75.IEC 61009 Residual current operated circuit breakers with integral over current protection for household and similar uses (RCBO's)
76.IEC 61010 Safety requirements for electrical equipment for measurement, control and laboratory use
79.IEC 61131 Programmable Logic Controllers.
80.IEC 61156 Multicore and symmetrical pair/qud cables for digital communications
82.IEC 61238, Compression and mechanical connectors for power cables for rated voltages up to 30 kV
83.IEC 61280 Field testing method for measuring single mode fibre optic cable
84.IEC 61286 Character set with electrotechnical symbols
85.IEC 61326 Electrical equipment for measurement, control and laboratory use - EMC
requirements
86.IEC 61378 Converter Transformers
87.IEC 61400 Wind turbines
88.IEC 61439 Low-Voltage switch gear and controlgear assemblies
89.IEC 61499 Function blocksDownload: eType1.com/f.php?FurInf
90.IEC 61537 Cable management - Cable tray systems and cable ladder systems
91.IEC 61557 Equipment for measuring electrical safety in low-voltage distribution systems
99.IEC 61642 Industrial a.c. Networks Affected by Harmonics - Application of Filters and Shunt
Capacitors
100.IEC 61643 Surge protective devices connected to low-voltage power distribution systems
101.IEC 61672 Electroacoustics – Sound level meters
102.IEC 61753 Fibre optic interconnecting devices and passive components performance
standard IEC 61784 Industrial communication networks - Profiles
103.IEC 61800 Adjustable speed electrical power drive systems
104.IEC 61803 Determination of power losses in high-voltage direct current (HVDC) converter
stations
105.IEC 61829, Crystalline silicon photovoltaic (PV) array - On-site measurement of I-V
characteristics
106.IEC 62262 Degrees of protection provided by enclosures for electrical equipment against
external mechanical impacts (IK code)
107.IEC 62271 Standards for high-voltage switchgear and controlgear

Sunday, August 28, 2011

BASICS OF ELECTRICAL

ATOMS

All meters (solid, Liquid, Gas) are composed by minute particals called Malicules. There are two part in Atom, 1. Nucleus 2.Extra Nucleus

a. Nucleus

The Nucleus contains Protons and Neutrons

Protons are positively charged particals and Neutrons have no particals

b.Extra Nucleus

Extra Nucleus contain only Electrons

Electrons are negatively charged particals and moves around the Molicules with different orbits.

The number of Protons are equels to Number of electrons in an Atom.

Atomic Wieght = No. of Protons + No. of Neutrons

Atomic Number = No. of Protons or No. of Electrons

Normally the Number of Protons and Number of electrons are equles in a body. So the resultant charge is zero and the body electrically neutral.

Charge

The charge is Electrical energy possessed by protons or Electrons in an Atoms

Unlike charges attract each other and like charges or repels each other.

The Law of Conservation

The Law of Concervation stats the algebraic sum of chares remain constant in a closed path. Therefore the charge can neither be created nor be distorted.

The unit of the charge

The charge on an electron is so small that is not convenient to select it as the unit charge. Normally Coulomb is the unit of charge. One Coulomb is equal to the charge on 6.28 X electrons.

Each protons has positive charge = 1.6 X C.

If 6.28 X Electrons remove from a neutral body then the body as positive charge 1 coulomb.

If we say that a body has a negative charge of 1 C we should remove 6.28 X electrons from that body.

Coulomb Inverse square Law

The force two point charges is directly proportional to product of the two charges and inversely proportional to square of distance between two charges.

F = 1/4π q1q2/

r - Distance between two charges

ε0 – The permittivity of free space

ε0 – 8.514

If charge placed in a material then

Permittivity = ε0 εr

εr – Relative permittivity of the material

Electric Field

The space around the charge in which the influence is felt is known as Electric field.

Electric field Intensity

The force experienced by an unit coulomb charge called Electric field Intensity.

E = F/q

F – Force in Newton

q – Charge in Coulomb

CURRENT AND VOLTAGE

American physicists TOLMAN and STEWART experimentally con formed that the electric current in a conductor is a carried by electrons. The electrons in outer most orbit will less bound with nucleus and called free electrons. The free electrons move at random from one atom to other atom in the materials.

Electro Motive Force

An external force necessary to move the free electrons in definite direction is called Electro Motive Force.

Faradays Law

When ever a conductor cut the magnatic field an E.M.F induced in the conductor.

E.M.F = BAL sinθ

B – Magnatic density in webber

A – Area of the conductor

L – Length of the conductor.

Theory of current (The Machanism of flow of current )

A metal piece contain a large number of free electrons moving in randam directin. The maxiumam speed the free electrons in the order of m/s. Due to e.m.f the electrons get accelerated and move in a definite direction. Due to electric field of moving electrons the electrons in the closed circuit also get accelerated and start to move.

The direction of moving electrons can be find by Flamings Right hand rule.

If E is the strength of the electric field applied from conductor closed circuit then the force on the electrons in the closed conductor

F = e.E

e- The charge on electrons in closed circuit.

The acceleration produced on on electrons in a closed circuit

a = F/m m – Mass of the electrons a = eE / m

Due to acceleration the velocity of an electron increase but happens only short time τ.

The electrons in a closed circuit contain The additional velocity acquired from e.m.f for τ time is called DRIFT VELOCITY.

Vd = a τ =( eE / m) τ.

Consider a wire of cross section ‘A’. Let ‘n’ be the number of free electrons per unit volume. The free electrons moves towards left with a constant drift velocity Vd.

Numer of free electrons passed through the area of cross section per unit time = nAVd. Therefore the charge that flows per unit time = nAVde. This also called the current flows through the wire I= nAVde.

This is relation between current and velocity

I= nA E τ/ m.

Electric current

The rate of follow of charge in any cross section of a wire is defined as the electric current.

I = Total charge flowing in a cross section / Time taken

If charge dq flows through a wire in small time dt. The electric current = dq / dt.

The unit of current is Ampere.

One coulomb of charge flow through the wire in one second is called one Ampere.

One ampere = 1 coulomb of charge (c) / 1 second (s) = 1

If there is no changes in rate of change of current and rate of change of time the the current is called steady current and if any one or both frequently change then the current called Alternating current .





Theory of Potential different

Consider a body in that one coulomb of negative charge is removed

Now the body is called positively charged body. Certain work was done to charge the body and it is stored in the body as potential energy.

AUTO RECLOSE

Auto Reclose Blocking Scheme
1. AR shall not be intiated under line is connected with generator bus unless proper analizes in the fulty line.
2. In case genarating power plant bus is connected to grid by medium and long lines,high-speed auto reclosing can be intiated by reverse direction (first chargeing the line from remote end and then reclose the CB at power plant end) for lines which restict the fult current to such a level that maximum shaft torques are with in the genarator specification under fault conditions.
3. AR shall not be intiated under the following conditions
a. BFP, BB protection trips
b. Direct transfer receiving Trips ( BF,PD)
c. SOTF Trips
d. Time delay trip
e. All type of communication failures ( 21 , 87L, BF,PD)
f. Both line & Bus side VT fuse failures

AR operate only zone -1 Ground to Earth Fault

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