BEE2133 Electrical Machine & Power System

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BEE2133 Electrical Machine Power System

• Chapter 4
• An Overview of Power System
• Norazila Jaalam

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Chapter outline

• Introduction
• Power system components
• - Generation, transmission, distribution
• Power system loads
• - Types of load, load demand, demand
• curve
• Power system in Malaysia
• - Energy generation company
• - IPP, co-generator
• - National Grid System

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Introduction
Support Components
Main Components
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Power System Components

• At power generating station (generating voltage)
  ? 11 20kV and frequency of 50 Hz
• Transform to higher voltage (transmission
  voltage) ? 132kV, 275kV and 500kV
• Transform to lower voltage (distribution voltage)
  ? 33kV or 11kV

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Power System Components
Generation
Step-up transformer (? voltage,?current)
Grid System (500kV, 275kV, 132kV, 66kV)
TNB
SESCO
SESB
Reduce the voltage 33kV,11kV
Transmission
Distribution
Loads
3 phase - 415 V, single phase - 240 V
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Power System Components
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Power System Components
AROUND TOWN RESIDENTIAL AREA - Underground
distribution to individual premises is at 415V
and 240 V
HOUSE - Overhead distribution to individual
houses is at 240V.
SMALL INDUSTRY - Most small factories receive
their electricity at 11kV
HEAVY INDUSTRY - Some have direct connections to
the transmission at 132kV
POWER STATION- Generator output at 11kV/20kV is
stepped up by transformer to 132kV 275kV and
500kV for transmission.
TRANSMISSION - Transmission is mainly at 132kV,
275kV and 500kV
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• Power System Components
• (Generation)

High voltages of 500kV, 275kV, 132kV are used
for transmitting electricity over the grid system
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Power System Components (Generation)

• Generation Plant Mix

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Combustion Turbine Power Plant
Power System Components (Generation)
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Coal-fired Power Plant-near a river/lake bcoz
large quantities of cooling water are needed to
condense the steam as it exhaust from the turbines
Power System Components (Generation)
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Hydroelectric Power Plant
Power System Components (Generation)
Sultan Mahmud Power Station, Kenyir
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Power System Components (Generation)
Bakun Dam Under construction
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TNB Power Stations
Power System Components (Generation)
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Power System Components (Transmission)
A transformer in a large sub-station reduces the
voltage to 33kV, 22kV,11kV
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Power System Components (Transmission)

• Lines/transformers operating at voltages above
  100 kV are usually called the transmission
  system.
• Consists of Transmission Line and Sub-stations
• Transmission network of 500kV, 275kV and 132kV
  known as National Grid.

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Power System Components (Transmission)

• Transmission Line
• Overhead Lines
• Cable
• Underground Cables
• Submarine Cables
• Sub-stations

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Transmission Parameters
Power System Components (Transmission)
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Power System Components (Transmission)
Transmission tower
Waist-Type Tower
Double Circuit Tower
Guyed-V-Tower
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Power System Components (Transmission)
Transmission tower
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Power System Components (Transmission)
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Overhead Line Conductors
Power System Components (Transmission)
Overhead Line Conductors
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Sub-station
Power System Components (Transmission)

• Size of substation
• Depends on transformer size
• Typical sizes
• 132kV 2 x 30MVA, 3 x 45MVA, 2 x 90MVA
• 275kV 2 x 180MVA, 3 x 180MVA, 2 x 240MVA
• Types of Sub-station
• Conventional outdoor
• Require bigger space
• GIS (gas insulated switchgear)
• Less space
• Outdoor or indoor

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Outdoor Sub-station
Power System Components (Transmission)
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GIS
Power System Components (Transmission)
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Sub-station Components
Power System Components (Transmission)

• Transformer
• Circuit Breaker / Switch Gear
• Isolator Switches
• Busbar
• Protection Relay Control Equipment

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Power Transformer
Power System Components (Transmission)
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Circuit Breaker
Power System Components (Transmission)
Spark gap. In event of a lightning strike on the
line, the current can jump the gap between that
ball and the protrusion on the tank, and make a
path to earth. This prevents overloading the
breaker.
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Circuit Breaker
Power System Components (Transmission)
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Insulators
Power System Components (Transmission)
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Power System Components (Distribution)
Supplies to rural communities are often reduced
from 11kV to domestic voltages (415/240V) by pole
mounted transformers.
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Power System Components (Distribution)

• Lines/transformers operating at voltages below
  100 kV are usually called the distribution
  system.
• Part of the electric utility system between the
  bulk power source and the customer service
  entrances (loads). 
• 33kV, 22kV, 11kV, 6.6kV, 415V and 240V

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Distribution Sub-station
Power System Components (Distribution)

• Distribution Intakes (33kV, 22kV)
• Distribution Substations (22kV, 11kV, 6.6kV)
• Indoor substation
• Outdoor substation
• Pole mounted substation
• Compact substation
• Underground substation
• Transformer capacity
• 100kVA, 300kVA, 500kVA, 750kVA and 1000kVA

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Distribution Intake
Power System Components (Distribution)
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Indoor Sub-station
Power System Components (Distribution)
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Underground Sub-station
Power System Components (Distribution)
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Compact Sub-station
Power System Components (Distribution)
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Outdoor Sub-station
Power System Components (Distribution)
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Pole-Mounted Sub-station
Power System Components (Distribution)
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Power System Loads

• Types of Load
• Residential
• Commercial
• Industrial
• Public Transportation
• Public Lighting
• etc.

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Residential Load
Power System Loads

• Consist of lighting, radio, TV, refrigerator,
  kitchen appliances, washing machine and etc.
• Usually, increases in the evening around 6 p.m.
  and return to a nominal value around 12 p.m.  

Commercial Load

• Consists of lighting, air-condition and small
  appliances.
• Shops, business premises, schools, universities
  etc.
• The load is fairly constant from 9am until 9pm
  with the exception of any mid-day break.

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Industrial Load
Power System Loads

• Mainly consists of motor load, air conditioner,
  lighting, welding and furnaces etc.
• It can be divided into small, medium and large
  category.
• The nature of industrial load curve depends on
  the number of shifts worked in the industry.

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Electricity Consumers
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Power System Loads

• Electricity energy cannot be stored.
• Generate electricity based on demand.
• Total power drawn by consumer fluctuates depends
  on the time of day and seasons.
• Demand Curve
• Plot each demand of electricity by consumer
  daily/annually

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Demand Curve
Power System Loads
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Load Duration Curve
Power System Loads

• 3 types of load
• Base load
• Has to be fed 100 of the time.
• Intermediate loads
• Have to be fed lt100 of the time.
• Peak load
• May occur 0.1 of the time.

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Load Duration Curve
Power System Loads

• Plot the duration of each demand on annual
  based.

100 8760hrs
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Load Duration Curve
Power System Loads

• Base-power stations
• Deliver full power at all times
• Nuclear, coal-fired stations
• Intermediate-power stations
• Respond relatively quickly to changes in demand
• Usually by adding/removing generating unit
• Hydropower stations
• Peak-power stations
• Deliver power for brief intervals during the day
• Put into service very quickly
• Equipped with prime movers that can be started up
  in a few minutes
• Diesel, pumped-storage turbines, gas turbines etc.

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Power System in Malaysia
Main Power Producer in Malaysia
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Power System in Malaysia

• Generation capacity of major power producer

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Independent Power Producer (IPP)
Power System in Malaysia

• Privately owned power producer.
• After privatization (1990) 18 IPP (long term
  power purchase agreement)
• Generates and sell power to TNB.
• Upload onto the National Grid.

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Power System in Malaysia
Independent Power Producer (IPP)

• Example
• YTL Generation Sdn. Bhd.
• Paka, Pasir Gudang
• Malakoff Berhad
• Lumut Power Station, Segari
• Prai Power Station, Butterworth
• Tanjung Bin Power Station, Johor
• Genting Sanyen Power Sdn. Bhd.
• Kuala Langat Power Station

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Co-Generator
Power System in Malaysia

• Minor electricity supply
• There are several small distributors buy
  electricity from the utilities or generate their
  own power, mostly by co-generation.
• Then, distribute to customers within specific
  areas such as industrial complexes.

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Power System in Malaysia
Co-Generator

• Example 1 Petronas Gas Sdn Bhd
• Generate electricity Co-generator
• Distribute power within two Integrated
  Petrochemical Complexes (IPC)
• Central Utilities Facilities (CUF) in Gebeng
  Kerteh
• Example 2 KKIP Power Sdn Bhd
• Purchase power from SESB
• Distribute power within Kota Kinabalu Industrial
  Park

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National Grid System
Power System in Malaysia

• primary electricity transmission network linking
  the electricity generation, transmission,
  distribution and consumption in Malaysia
• operated and owned by TNB
• more than 420 substation in Peninsular Malaysia
  are linked together by the extensive network of
  transmission lines operating at 132kV, 275kV and
  500kV
• Power generated by TNB and IPP is carried by the
  National Grid towards customers connected to the
  various distribution networks
• electrically interconnected to the transmission
  network of the Electricity Generating Authority
  of Thailand (EGAT) and also to Singapore Power

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National Grid System
Power System in Malaysia
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Power System in Malaysia
National Grid System (main)
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Power System in Malaysia
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Power System in Malaysia
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National Grid Interconnection
Power System in Malaysia

• TNB EGAT
• - HVAC 132kV/115kV overhead lines
  interconnection between Bukit Ketri (TNB) and
  Sadao (EGAT) 80MW
• HVDC 300kV interconnection overhead lines between
  Gurun (TNB) and Ban Khlong Ngae (EGAT) 300MW
• TNB SINGAPORE POWER
• - HVAC 275kV/230kV submarine cables
  interconnection between Pasir Gudang (TNB) and
  Senoko (Singapore Power) 200MW

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Objectives of TNB-EGAT HVDC Project

• Peak lopping TNB imports during TNBs peak load
  (morning) and export during lower demand
  (evening)
• Sharing of spinning reserves both TNB and EGAT
  reduce their respective spinning reserve
• Economic power exchange TNB may export if its
  price is lower than EGAT and vice versa
• Help each other during system emergencies/crisis

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Advantages of national grid system
Power System in Malaysia

• Provide multiple paths between various generation
  sources and loads
• Provide for power transfers from one geographic
  area to another to achieve overall system
  operating economics
• Interconnect the bulk power facilities of
  individual power station/utilities so that they
  can better withstand major disturbances

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Power System in Malaysia

• Other advantages
• Stability
• Load sharing
• Continuity of service
• Maintenance, breakdown
• Economy
• Cheap efficient

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National Load Dispatch Centre (NLDC)
Power System in Malaysia

• Located in Bangsar, KL
• Objectives
• Grid system requires a grid controller/operator
  system.
• In order to ensure the supply of energy is safe
  and reliable.

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NLDC Function
Power System in Malaysia

• Maintains system stability
• Frequency control
• Voltage within limits
• Achieve minimum operating cost
• Optimize transmission losses
• Merit order generation
• maintain spinning reserve requirements
• co-ordinate generation and transmission
  maintenance outages
• Restoration of supply after system fault

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Future ASEAN Power Supply Interconnection