slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
DC supply systems in 400 kV sub stations PowerPoint Presentation
Download Presentation
DC supply systems in 400 kV sub stations

Loading in 2 Seconds...

play fullscreen
1 / 14

DC supply systems in 400 kV sub stations - PowerPoint PPT Presentation


  • 136 Views
  • Uploaded on

DC supply systems in 400 kV sub stations . Why a DC source ? Why not AC source ? What for DC source is used in 400 kv sub stations How many levels of DC sources available ? Where from DC source is obtained? . DC supply systems in 400 kV sub stations .

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'DC supply systems in 400 kV sub stations' - orea


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

DC supply systems in 400 kV sub stations

Why a DC source ?

Why not AC source ?

What for DC source is used in 400 kv sub stations

How many levels of DC sources available ?

Where from DC source is obtained?

slide2

DC supply systems in 400 kV sub stations

  • DC source is more stable , Local source,
  • not dependent on grid
  • 2. AC source is prone to disturbances, dependent
  • on grid condition
  • 3. DC source is mainly used for relays, Breakers,
  • Isolators
  • 4. Levels of DC source are 220 V DC and 50 V DC
  • 5. DC source is obtained from Batteries.
slide3

Charger

Load

DC supply systems in 400 kV sub stations

DC Switch

Boards

AC source Charger Battery Load

  • Requirement for supervision Relays:
  • Relay are meant for supervision of Power system 24*7 *52
  • No interruption is permitted
  • Two DC sources are designed from 220 KV power system level and above
  • All protection relays are divided into two groups
  • 5. One group of relays are fed from DC source –I and other group from
  • Second Source
slide4

DC supply systems in 400 kV sub stations

DC source-2

DC Source –I

Feeder Protection distribution

Feeder Protection distribution

slide5

DC supply systems in 400 kV sub stations

  • Critical Equipment in DC Source systems :
  • Chargers --- Full wave rectifiers , Half wave rectifiers, with 1 % ripples
  • Batteries --- 109 Nos for 220 V system with 88th cell tapping ,
  • 24 Nos for 50 V systems with 18th cell tapping.
  • C. DC distribution boards ---- DC switches , Fuses
  • Maintenance of DC systems
  • Voltage measurement between + Pole to Ground and - ve pole to Ground.
  • Monitoring of leakage current in DC systems -- 4-6 milli amps
  • Less leakage more healthiness of DC systems
slide6

+ ve pole

+ ve pole

- Ve pole

- Ve pole

DC supply systems in 400 kV sub stations

  • DC Earth faults and its effects :
  • Any One pole earthing – No problem but to be rectified.
  • Same pole earthing in both source ?
  • Two different pole earthing in different sources ?

DC Source –II

DC Source –I

Earth fault relays shall give alarm

slide7

+ ve pole

+ ve pole

+ ve pole

+ ve pole

- Ve pole

- Ve pole

- Ve pole

- Ve pole

DC supply systems in 400 kV sub stations

Circuit breaker tripping is possible in this case.

Fuse blows out

slide8

+ ve pole

+ ve pole

- Ve pole

- Ve pole

DC supply systems in 400 kV sub stations

slide9

+ Ve

+ Ve

- Ve

- Ve

Relay contact

Relay contact

Trip coil

Trip coil

CB aux

CB aux

DC supply systems in 400 kV sub stations

Source –I

Source -II

slide10

DC supply systems in 400 kV sub stations

  • There is possibility of insulation damage in Source CB trip circuits
  • B. There is always possible for discharge of capacitance that is
  • present with DC cables insulation
  • C. The moment double earthing happens, then discharge is possible
  • through the trip coil and breaker can trip. This can happen for the breakers
  • where cable insulation is week and damaged.
  • To prevent such mal operation of breakers, when ever ingle pole
  • earthing occurs, same is to be identified and rectified.
slide11

AC supply systems in 400 kV sub stations

  • AC supply is for
  • Transformer Cooling systems
  • Circuit breaker compressors
  • Batteries
  • Control room lighting
  • AC plant
  • Fire fighting systems
  • Switch yard lighting
  • Street lighting
  • Colony power supply
  • Stores yard lighting
slide12

DC supply systems in 400 kV sub stations

Tertiary supply 11/33 kV source DG source

F/F ACP SWYD ACP F/F SWYD Lighting Colony

DB DB DB DB DB DB DB DB

440 V Main Distribution system

slide13

AC supply systems in 400 kV sub stations

  • AC systems – Problems
  • Major problems are power cable failure from Transformer /
  • DG set to Main distribution board.
  • 2. Failure is due to improper laying of power cables
  • 3. Other problems are in Lighting system