Planning of Electricity Distribution Networks

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University of Turkish Aeronautical Association
Electric and Electronic Engineering
DepartmentPresented and designed Khalid
AlHashemi

Planning of Electricity Distribution Networks
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Contents

• Introduction
• Voltages Classification
• Electric power system stages
• 33/11KV substation
• Diversity factor
• Calculate the current of 11KV Feeder
• Calculate the current of Transformer on 11KV
  Side
• Kiosk
• Pillar
• Design Low Voltage networks
• Conclusion

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Introduction

• In order to Design a perfect Electrical
  Distribution Network , we should have a knowledge
  in Electrical powers generation and transmission
  
• The most important task in the stage of
  establishing basic data is the estimation of the
  power required for supply.
• In order to attain a high level of efficiency,
  the components should work with a load of 70 to
  80 of the maximum power output.

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Voltages Classification

• We can classify Voltages to five divisions
  according to their values
• 1- 600 V and below are referred to low
  voltage
• 2- 600 V - 69 kV are referred to medium
  voltage
• 3- 69 kV-230 kV are referred to high
  voltage
• 4- 230 kV-1100 kV are referred to
  extra high voltage
• 5- 1100 kV and above referred to
  ultra high voltage

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Electric power system stages

• There are three stages of electric power system
  from generation to end-use customer
• 1- Generation .
• 2- Transmission .
• 3- Distribution .

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Electric Power system stages
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Sample diagram shows the stages of voltages
value from generation to end-use customer (Iraq
values)
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33/11KV SubstationTransformerMost of 33/11KV
Substation has tow transformers 2 31.5MVA
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33/11KV Substation11KV equipmentThe total
power of two 33/11KV transformers is 231.5MVA
,so the substation has total 14 (11KV) feeders
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33/11KV substation connection There are
three ways to connect the 33/11KV substation
1- The two power transformers feeding form
Different 33KV incoming sources. (normal case)

Schematic Diagram of 33/11KV substation
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33/11KV substation connection
2- The two power transformers feeding form same
33KV incoming sources because
there is a problem with incoming 33KV source 2
.( Emergency case)
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33/11KV substation
connection 3- When there is a problem with
transformer 2. All low voltages feeders will feed
from transformer 1 , source 1 .
.( Emergency case)
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Diversity factor

• Diversity factor is a measure of the
  probability that a particular
• piece of equipment will turn on
  coincidentally to another piece
• of equipment , it is 70 for total
  demands

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Calculate the current of 11KV Feeder

• To find out the number of 11/0.4KV transformers
  according to their capacities in (KVA) for each
  11KV feeder ,we should know the allowed value of
  current for 11 KV feeder in (Amper) and the
  values of current in (Amper) for all available
  transformers 11/0.4 KV.
• Since 33/11KV transformer has power 31.5MVA ,and
  it has seven 11KV feeders , then each 11KV Feeder
  has about 6000KVA (take Diversity factor
  inconsideration ) , then we can calculate its
  current

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Calculate the current of Transformer on 11KV Side

• To calculate full load current from parameters
  available in Transformers name plate as below
• Transformer Rating
• HT Voltage 11KV
• LV Voltage 415 (p-p)
• KVA Rating 1000KVA

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Calculate the current of Transformer on 11KV Side

• To calculate full load current from parameters
  available in Transformers name plate as below
• Transformer Rating
• HT Voltage 11KV
• LV Voltage 415 (p-p)
• KVA Rating 250KVA

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The number of transformers for one 11KV Feeder

• In design the total current that taken from
  11/0.4KV transformers should not exceed 315A
• If we have only 1000KVA 11/0.4 transformers

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The number of transformers for one 11KV Feeder

• In design the total current that taken from
  11/0.4KV transformers should not exceed 315A
• If we have only 250KVA 11/0.4 transformers

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Kiosk

• Kiosk substations are an important part of
  the electricity network.
•   They convert higher voltage electricity into
  the lower voltage. 
•  Approximate dimensions 2.7m in length, 1.5m
  wide and 1.75m high
• They contain 3 main parts high voltage
  equipments , transformer
• and low voltage equipments.
• There are two types 2 isolators and 3
  isolators .
• Power of transformer have one of there values
  ( 630KVA , 1000KVA,
• 1250KVA and 2000KVA )

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Kiosk
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Kiosk Diagram 1000KVA
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Side view of Kiosk ( Transformer )
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High Voltage side of Kiosk ( H.V 3- isolators )
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Low Voltage side of Kiosk ( Circuit Breakers )
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Distribution and Connection between kiosks with
two substation (33/11KV) normal case
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Distribution and Connection between kiosks
with two substation (33/11KV)
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Pillar

• Its a box that include bus bar which is last
  distribution point between the distribution
  network and customer. It designed to feed 5 users
  at maximum

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Design Low Voltage network according
to the kiosk and pillars place and the
cables size
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Design Low Voltage network according
to the kiosk and pillars place and the
cables size
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Design Low Voltage network according
to the kiosk and pillars place and the
cables size
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Conclusion

• Electrical power is generated at different
  generating stations. And the energy has along
  path to get to consumer and its very important to
  put any thing with criterion to get optimize
  power at cheapest cost , less losses and high
  performance.