Download The substation

Source: Lakervi & H
Holmes
The substation
Olof Samuelsson
Outline
• The substation
• Substation equipment
• Overhead lines
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
2
From generator to customer
Generation
|
Transmission
|
Distribution
|
Consumption
Source: vattenfall.se
Östra mottagningsstationen, Lund
At the city limit
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
3
Substation functions
• Voltage transformation (reduction)
– Power transformer
• Connection point for local networks
• Switchyard for network configuration
– Bus bars,
bars circuit breakers,
breakers disconnectors
• Monitoring point for control center
– Potential and current transformers
• Fuses and other protection
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
4
Substation equipment symbols
ENGLISH
Busbar
Generator
Two-wdg
Two
wdg transformer
Line
Circuit breaker
Disconnector
Surge arrester
Current transformer
Potential transformer
SVENSKA
Samlingsskena
g
Transformator
Ledning
Effektbrytare
Frånskiljare
Ventilavledare
Strömtransformator
Spänningstransformator
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
5
Layout
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
6
Circuit breaker
S d USA
Sweden
Sourcee:ABB
Open Closed
• Interrupts large current
– Several kA
– Short-circuit current
– Hidden contacts
• Control
– Protection systems
– Manual remote
• Design challenge
– Speed and current
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
7
Disconnector / Isolator
• Interrupts small current
– Load current
• Visible interruption
• Manual control or motorized
• Design challenge: Weather
Sweden USA
Open Closed
Open
p
Closed
Source: Nicklasson
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
8
Disconnecting circuit breaker
• Combines breaker and disconnector
• More reliable and compact
Lindome 400 kV station
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
9
Current transformer
B
Source:ABB
• Reduces current
– Typically 1000/2 A
• Current monitored
– Control center
– Protection equipment
– P, Q transducers
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
10
Sou
urce:ABB
Voltage/potential transformer
• Reduces voltage
– Typically x kV/110 V
• Voltage monitored
– Control center
– Protection equipment
– P, Q transducers
Al C voltage
lt
di
id
• Also
divider
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
11
Surge / lightning arrester
• O
Overvoltage
lt
trap
t
• Alternative to air gap
• Nonlinear resistance
• Short-circuits high
voltages
o tages to ground
g ou d
Source: ABB
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
12
GIS - Gas Isolated Switchgear
SF6
Air
Source: Lakervi
• SF6 gas
g
– Isolates much better than air - reduces size
– Greenhouse gas
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
13
Source: Nicklasson
Transmission towers
400 kV
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
750 kV
Substation
14
Insulator disks
Voltage level
Source:Glover & Sarma
Flashover distance
Number of disks
Air humidity
y
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
15
Effects of short-circuit current
• Vibration due to magnetic forces
– Parallel conductors are attracted (F=B·i·l)
• Arc
– Compare with welding
g from current and arc
• Heating
– Fire and explosion
• See http://205.243.100.155/frames/longarc.htm
Lund University / LTH / MIE / Industrial Electrical Engineering and Automation
Substation
16