1. ECE 476 POWER SYSTEM ANALYSIS
Lecture 26
Distribution Systems
Muhammad Abdul Retha lefte Al-Badri
Department of Electrical and Computer Engineering

2. Announcements Be reading Chapter 14
Last homework is 12.3, 12.11, Needs to be done before the final, but not graded.
Final exam is as given on the UIUC website. That is, Tuesday Dec 13 from 7 to 10pm here (218 Ceramics).
Final is comprehensive, with more emphasis on material since exam 2.
Three note sheets allowed (e.g., ones from previous two exams and one new note sheet)

3. Electricity Delivery Generation: 50-1300MVA, up to 20kV
Transmission: 230kV up to 765kV
Can include: HVDC, ac-dc links
Subtransmission: kV
Can include: taps for large single customer
Primary distribution substations: MVA, kV
Can include: LTC, capacitor banks, reclosers
Distribution feeders: 4.16kV up to 34.5kV
Secondary distribution: kVA, V
Meters

4. Electricity Delivery

5. Electricity Delivery

6. Primary Distribution
15kV class, 4 wire multigrounded is most common

7. Primary Distribution
Includes everything from the distribution substation to the distribution transformers
Rural areas served by overhead lines
Urban areas served by underground systems
3 common topologies
Radial
Loop
Network

8. Primary Radial Systems

9. Primary Radial Systems
Three phase feeder mains of length 1 to 30 miles
Single phase laterals branch off main feeder
Try to balance the load on the 3 phases
Economical and widely used in low load density areas
Reclosers are used on overhead lines to minimize loss of load
Typically have 3 shots before lockout
Sectionalizing fuses also reduce downtime