PPT ON SWITCHYARD

PPT On SWITCHYARD

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SWITCHYARD Presentation Transcript:

1. What is a Switchyard ?
 It is a switching station which has the following credits :
(i) Main link between Generating plant and Transmission system, which has a large influence on the security of the supply.
(ii) Step-up and/or Step-down the voltage levels depending upon the Network Node.
(iii) Switching ON/OFF Reactive Power Control devices, which has effect on Quality of power.

2. SWITCHYARD EQUIPMENTS
Equipments commonly found in switchyard :
Lightening arrestor
Current transformer
Voltage transformer
Power transformers / I.C.T.
Bus bar and clamp fittings
Support structure
Isolators
Circuit Breaker
Wave traps
Earthing switch

3. Functions of various equipment :
* Transformers : - Transforms the voltage levels from higher to lower level or vice versa, keeping the power constant.
* Circuit breakers : - Makes or automatically breaks the electrical circuits under Loaded condition.
* Isolators : - Opens or closes the electrical circuits under No-load conditions.
* Instrument transformers : - For stepping-down the electrical parameter (Voltage or Current) to a lower and safe value for Metering and Protection logics.
* Earth switch : - Used to connect the charged body to ground to discharge the trapped charge to have a safe maintenance zone.

4. Functions of various equipment :
* Lightning arrestors : - Safe guards the equipment by discharging the high currents due to Lightning.
* Overhead earth wire : - Protects the O/H transmission line from Lightning strokes.
* Bus bar : - Conductors to which a number of circuits are connected.
* Wave Traps/Line traps : - Used in PLCC circuits for Communication and Protection of Transmission lines * Reactive Power control devices : - Controls the reactive power imbalance in the grid by switching ON/OFF the Shunt Reactors, Shunt Capacitors etc.,
* Current Limiting Reactors : - Limits the Short circuit currents in case of faulty conditions.

5. Bus Switching Schemes :
Bus Bar Schemes
* Single Sectionalised bus
* Main & Transfer bus
* Sectionalised Main bus with Transfer bus
* Sectionalised Double Main & Transfer bus
Breaker Schemes
* Ring bus
* One and Half breaker
* Double bus Double breaker

6. Factors effecting the selection of Switching Scheme :
* System Security
* Operational Flexibility
* Simplicity of Protection arrangements
* Ability to limit the Short Circuit levels
* Maintenance
* Ease of extension
* Total land area
* Cost

7. What is a Switchgear ?
 “The apparatus used for Switching, Controlling and Protecting the Electrical Circuits and equipment”.
Need of Switchgear :
* Switching during normal operating conditions for the purpose of Operation and Maintenance.
* Switching during Faults and Abnormal conditions and interrupting the fault currents.

8. Relay :
“A device that detects the fault and initiates the operation of the Circuit breaker to isolate the defective element from the rest of the system”.
* The relays detect the abnormal conditions in the electrical circuits by constantly measuring the electrical quantities which are different under normal and faulty conditions.

9. Requirements of Protecting relaying :
Selectivity - Ability to select the faulty part and isolate that part without disturbing the rest of the system. Speed - Ability to disconnect the faulty part at the earliest possible time.
Sensitivity - Ability of the relay to operate with low value of actuating quantity.
Reliability - Ability of the system to operate under pre-determined conditions

10. For more please refer our PPT. Thank You.

Source: Power Point Presentations