Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Make your likes visible on Facebook?

Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.

No, thanks

Differences between AIS-GIS

No description
by

Mahmoud Abdelfatah

on 12 July 2014

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Differences between AIS-GIS

gas insulated substation

Differences between AIS-GIS

High-Voltage cables of various types are connected to SF6 switchgear via cable connection assembly & also it enables the GIS & Cables to be tested separated

cable termination

VTs are one-phase (phase-to-ground connection) and can be inductive or capacitive

4-Voltage Transformer

2 - High Speed Earthing Switches. These are operated by spring energy. Spring is charged by motor-mechanism

The earth Switch is mounted direct on the enclosure( Fig.) Earthing Switch has to satisfy various requirements. For Earthing isolated sections of Switchgear for protection of personal during maintenance the maintenance Earthing Switches are employed

local control cabinet (LCC) is provided for each circuit breaker
position (Figure). The control and power wires for all the operating mechanisms, auxiliary switches, alarms, heaters, CTs, and VTs are brought from the GIS equipment modules to the LCC using shielded multi conductor control cables.
In addition to providing terminals for all the GIS wiring, the LCC has a mimic diagram of the part of the GIS being controlled. Associated with the mimic diagram are control switches and position indicators for the circuit breaker and switches. Annunciation of alarms is also usually provided in the LCC.
Electrical interlocking and some other control functions can be conveniently implemented in the LCC.

Control System

world largest SF6 gas insulated switchgear at Three Gorges Dam in China GIS 73 bays 550 kV

A switchgear is a general term that covering switching devices and their combination with associated control, measuring, protective and regulating equipment, also assemblies of such devices and equipment with associated inter connections, accessories, enclosures and supporting structures, intended in principle for use in connection with generation, transmission, distribution and conversion of electric energy.

Switchgear Definition

1 – Circuit Breaker .            
   2 – Spring Mechanism .    3 –Disconnected .               
   4 – Slow Earthing Switch    5 – Earthing Switch.    6 – Current Transformer.       7 – Voltage Transformer.    
   8 – HV cable connection.

High voltage Gas Insulated Switch gear Double Bus-Bar (make Alostom)

Enclosures

Conductors which conduct the main circuit current and transfer power these are of copper or aluminum tubes

Conductors need insulation above grounded enclosures. Conductors also       need phase to phase insulation, In SF6 GIS these insulation requirements      are met by cast resin insulators and SF6 gas insulation

Gas filled modules have nonmagnetic enclosures. Enclosures are of aluminium, alloy or stainless steel. Adjacent modules are joined by means of multi-bolts tightened on flange


each of main components has its own gas -filled metal
enclosed module.

Gas filling, monitoring system.

Auxiliary low voltage DC and low
voltage AC supply system, control,
protection and Monitoring systems.




GIS Requirements

Advantages of GIS….

Reduced maintenance and consequently, lower cost
The safety is increased
-As the enclosures are at earth potential there is no possibility of accidental contact by service personnel to live parts.
- GIS have no risk for fire and explosion due to leakage of oil
They generate no noise and have no radio interference
The maintenance of GIS is free
It offers solutions
-Industrial areas where space and pollution problems.
-Mountain areas where ice and snow are major problems

are used for ear thing and short-circuiting de-energized station components
In general, earthing switches are combined with the adjacent Disconnectors to form one unit.
However, earthing switches can also be installed separately
There are several versions of Earthing Switches for following applications
1 - Maintenance Earthing Switches. These are single pole or three pole units; manually operating mechanism with a provision of filling motor mechanism.

3-Earthing switches

Disconnector:
1-     supporting insulator
2-     fixed contact
3-     moving contact
4-     ear thing Switch
5-     driving insulator

1 - Off Load Isolator(DS)
is an isolator which is operated in a circuit either when the isolator is already disconnected from all sources of supply and the current may be due to capacitance currents of bushings, Bus-Bar connections, and very short lengths of cable.
Disconnectors have a moving contact that opens or closes a gap between stationary contacts when activated by an insulating operating rod that is itself moved by a sealed shaft coming through the enclosure wall, the Figure shows a Disconnector with its main parts.
The stationary contacts have shields that provide the appropriate electric field distribution to avoid too high a surface stress.
Disconnectors are almost entirely actuated by motor driven operating mechanisms

2- Disconnector Switch(ISOLATOR)

Is mechanical switching devices able to make, carry and interrupt currents occurring in the circuit under normal conditions, and can make, carry for a specified time and break currents occurring in the circuit (e.g. short circuit) under specified abnormal conditions. A circuit breaker is an automatically-operated electrical switch designed to protect an electrical from damage caused by overload or short circuit.
Its basic function is to detect a fault condition and, by interrupting continuity, to immediately discontinue electrical flow.
Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation

1- Circuit Breaker

Fig: essential parts of Gas insulated substation

Gis components

Reduced required space

Reliable
-The complete enclosure of all live parts guards against any impairment of the insulation system

The installations are dielectrically and totally tested site (unlike conventional substations)

Reduced erection and assembly times:
-Heavy foundations for galvanized steel structures, equipment support structures ...etc are eliminated
-The principle of building block construction reduces the installation time to a few weeks
-Each conventional substation requires several months for installation.

Advantages of GIS….

consists of Oil/SF6 bushing, the enclosure, the main circuit end terminal & removable connection.

For High-Voltage test on GIS, transformer is isolated from switchgear by dismantling the removable connection

Voltage Transformer Module
For rated voltage up to 145 kV inductive Transformer with cast resin coil For rated voltage of 245 kV inductive VT with SF6 gas as main insulation.







For 300 kV and above, Capacitive Voltage Transformers are preferred Inductive type Voltage Transformer. . They are connected to the Switchgear with the standardized connecting flange via a barrier insulator.

Voltage Transformers are induction type and are contained in their own   SF6 compartment, separated from the other parts of the installation.
The active portion consists of a core, upon which are placed the secondary windings and the high voltage winding.
Provision is made for up to two secondary windings for measurement and an additional open delta winding for earth fault detection. A synthetic film separates the different wraps of the windings. The Transformers can be installed Any where on the substation. 

Gas insulations tend to be much more expensive than air insulated installations with the same ratings.

Excessive damage in case of internal fault. Long outage periods as the repair of damaged part at site may be difficult.

Care should be taken that no dust particles enter into the live compartments which results in flash over.

Procurement of gas and supply of gas to site is problematic, adequate stock of gas must be maintained.

Disadvantages of GIS

in the single phase enclosed Core of CT is located outside the enclosure&inside for three phase
Gas compartment to reduce access of moisture and to suppress gas-tight bushings for secondary connections.


Current Transformer (Make ABB)
1 - Gas tight enclosure       
  2 - Terminal box     
  3 - Secondary winding













Current Transformer  (Make Alostom)       
       1- Main conductor.  
             2- Secondary winding.          3- Shunt Insulating .

3-Current transformers:

R
educed required space

Reliable
-The complete enclosure of all live parts guards against any impairment of the insulation system

The installations are dielectrically and totally tested site (unlike conventional substations)

Reduced erection and assembly times:
-Heavy foundations for galvanized steel structures, equipment support structures ...etc are eliminated
-The principle of building block construction reduces the installation time to a few weeks
-Each conventional substation requires several months for installation.

Advantages of GIS….

Advantages of GIS….

Reduced maintenance and consequently, lower cost
The safety is increased
-As the enclosures are at earth potential there is no
possibility of accidental contact by service personnel to live parts.
- GIS have no risk for fire and explosion due to leakage of oil

They generate no noise and have no radio interference

The maintenance of GIS is free
It offers solutions
-Industrial areas where space and pollution problems.
-Mountain areas where ice and snow are major problems

Gas insulations tend to be much more expensive than
air insulated installations with the same ratings.

Excessive damage in case of internal fault. Long
outage periods as the repair of damaged part at site may be difficult.

Care should be taken that no dust particles enter into the live compartments which results in flash over.

Procurement of gas and supply of gas to site is problematic, adequate stock of gas must be maintained.

Disadvantages of GIS

Differences between AIS-GIS

Enclosures

Conductors which conduct the main circuit current and transfer power these
are of copper or aluminum tubes


Conductors need insulation above grounded enclosures. Conductors also
need phase to phase insulation, In SF6 GIS these insulation requirements
     are met by cast resin insulators and SF6 gas insulation


Gas filled modules have nonmagnetic enclosures. Enclosures are of
aluminium, alloy or stainless steel. Adjacent modules are joined by means of
multi-bolts tightened on flange


each of main components has its own gas -filled metal
enclosed module. enclosures

Gas filling, monitoring system.

Auxiliary low voltage DC and low
voltage AC supply system, control,
protection and Monitoring systems.




GIS Requirements

Fig: essential parts of Gas insulated substation

Gis components

1 – Circuit Breaker .            
   2 – Spring Mechanism .
   3 –Disconnected .               
   4 – Slow Earthing Switch   
5 – Earthing Switch.
   6 – Current Transformer.     
  7 – Voltage Transformer.    
   8 – HV cable connection.

High voltage Gas Insulated Switch gear Double Bus-Bar (make Alostom)

world largest SF6
gas insulated
switchgear at
Three Gorges Dam
in China GIS
550 kV

A switchgear is a general term that covering switching devices and their combination with associated control, measuring, protective and regulating equipment, also assemblies of such devices and equipment with associated inter connections, accessories, enclosures and supporting structures, intended in principle for use in connection with generation, transmission, distribution and conversion of electric energy.

Switchgear Definition
Full transcript