MCCCD Program Description

Electrical Distribution Systems

Course: ABC223

First Term: 2004 Fall

Lecture 1.5 Credit(s) 1.5 Period(s) 1.5 Load
Subject Type: Occupational
Load Formula: S

Description: Distribution systems, electrical drawings and identification of electrical symbols. National Electrical Code (NEC) regulations governing distribution systems. High and low voltage portions of distribution systems. Component connection, transformer operation and calculation of transformer sizes and maximum loads for Open-Delta systems. Practical applications for capacitors and rectifiers. Calculation of power factor of electrical circuits and trouble shooting

MCCCD Official Course Competencies
1. Describe the fundamental operating aspects of a generating station and the main aspects of an electrical power system. (I) 2. Describe the role of the transmission sub-station in power distribution including: typical power ratings for large power transformers, voltage control during transmission and how sub-station equipment is rated. (II) 3. Identify, and interpret common symbols in single-line diagrams and secondary one-line diagrams and shop drawings. (III) 4. Describe how a transformer operates and explain the principle of mutual induction and how it relates to transformers. (IV) 5. Describe types of transformer core construction, list the advantages and disadvantages of specific designs and the characteristics of a well designed transformer. (V) 6. Identify specific transformer connections and differentiate their properties and uses. (VI) 7. Describe the purpose of control transformers and determine the proper type for given applications. (VII) 8. Define overcurrent protection related to small power transformers according to NEC specifications. (VIII) 9. Explain the need for grounding transformers and the appropriate NEC regulations for their installation. (IX) 10. Use the Power Factor Equation to calculate the effects of capacitors, resistors, reactors, diodes and rectifiers on an electrical system. (X) 11. Describe the purpose of vectors, perform calculations using vector principles, interpret phasor diagrams and measure voltage drop using vector principles.(XI) 12. Demonstrate specific troubleshooting procedures for transformers using appropriate testing devices. (XII)
MCCCD Official Course Competencies must be coordinated with the content outline so that each major point in the outline serves one or more competencies. MCCCD faculty retains authority in determining the pedagogical approach, methodology, content sequencing, and assessment metrics for student work. Please see individual course syllabi for additional information, including specific course requirements.

MCCCD Official Course Outline
I. Electrical Distribution Systems A. Generating station 1. Electrical components 2. Sub-stations B. Synchronization C. Sub-station service supply II. Transmission Systems A. Sub-station switching system B. Voltage regulation in sub-stations C. Distribution systems 1. Rural sub-stations 2. Industrial sub-stations 3. High voltage lines 4. Low voltage lines III. Electrical Symbols A. Single-line drawings B. One-line diagram interpretation 1. Service order numbers 2. Unit numbers 3. Title block 4. Revision notes C. Secondary one-line diagram interpretation D. Shop drawings IV. Transformers A. Mutual induction B. Induction in transformers C. Magnetic flux in transformers 1. Leakage flux 2. High leakage 3. Low leakage V. Transformer Construction A. Core construction 1. Open 2. Closed 3. Shell 4. Core loss B. Core Types 1. Butt 2. Wound 3. Mitered C. Transformer characteristics VI. Transformer Connections/Properties/Uses A. Single-phase light and power B. Y-Y for light and power C. Delta connected 1. Center tap 2. high leg D. Open delta E. Tee-connected F. Dry type transformers G. Zigzag 1. Size calculations 2. Current flow H. Buck and boost transformers 1. Boost mode 2. Buck mode 3. Three phase 4. Single phase VII. Control Transformers A. Purpose B. Types C. Characteristics D. Applications VIII. NEC Requirements A. Over-current protection 1. NEC 2. Schematics 3. E/X fuses 4. Calculations B. Overcurrent protection for small power transformers IX. Transformer Grounding A. Need B. NEC Requirements C. Installation X. Power Factor A. Calculation B. Capacitors 1. NEC requirements 2. Calculations C. Resistors and reactors D. Diodes and rectifiers XI. Vectors A. Phasor diagrams 1. Typical vectors 2. Calculations B. Practical application of phasor diagrams C. Voltage drop 1. Measurement 2. Resistance 3. Inductance 4. Voltage/current relationship XII. Trouble Shooting A. Procedure 1. Pre-check 2. Double check 3. Find and correct B. Troubleshooting 1. Warning signs 2. Causes 3. Diagnostic tools

MCCCD Governing Board Approval Date: 6/22/2004

All information published is subject to change without notice. Every effort has been made to ensure the accuracy of information presented, but based on the dynamic nature of the curricular process, course and program information is subject to change in order to reflect the most current information available.