FUNDAMENTALS OF POWER DISTRIBUTION SAIEE-1337-V : 2 CPD credits : Category 1

Transcription

1 THE SOUTH AFRICAN INSTITUTE OF ELECTRICAL ENGINEERS FUNDAMENTALS OF POWER DISTRIBUTION SAIEE-1337-V : 2 CPD credits : Category 1 OVERVIEW : 1. Introduction to Distribution, Transmission and Generation (D1) 2. Networks configurations and reliability (D2) 3. Earth Fault Protection in L.V. Systems (D3) 4. Electric Shock hazard (D4) 5. Cable selection for MV and LV distribution (D5) 6. Sizing of cables (D6) 7. Effect of Fault Current on Cable (D7) 8. Cables for Direct-On-Line Starters (D8) 9. Overhead Lines (D9) 10. Motor Control Centres design (D10) 11. MCC Schematics (D11) 12. Motor Control Aspects (D12) 13. Lighting and Small power Distribution (D13) TARGET AUDIENCE This workshop is relevant to the following personnel in the electrical field in mining and industrial environments. a. Design Engineers, Technologists and Technicians b. Consulting Engineers c. Design Draughtsman d. Project Planners and Estimators e. Process Plant Engineers COST : R6, (incl. teas, lunches and course material) *Note: If proof of payment is received before commencement of the course, the following rates will apply: Non member R6,300 ; SAIEE member R4,950. COURSE DATE: 6-7 September 2016: SAIEE HOUSE, JHB Registration : 08:00 08:30 Workshop : 08:00-17:00 KEY BENIEFITS : * Sets out power configurations and related reliability * Overview of electrical hazards and safety precautions including earth fault protection * The Workshops covers Motor Control Centre (MCC) design including schematics * Engaging in calculations for economic and safe sizing power cables * Provides insight into motor control aspects * Provides voltage drop calculations in L.V. reticulation * Thermal and dynamic stress on cables during short circuit PRESENTERS WALTER STRELEC & GAVIN STRELEC MSAIEE received his BSc in Electrical Engineering at the University of the Witwatersrand in He has been a Registered Professional Engineer with ECSA since 2003 and has had 14 years related experience in the electrical utility industry with ESKOM. He is currently Chief Engineer at ESKOM s Research Test and Development and is Chairman of the NRS Industry workgroup to develop standards for copper theft. REGISTRATION : CONTACT DETAILS ROBERTO BENITES Roberto@saiee.org.za

2 LV & MV Distribution Design for Industrial and Mining Applications Key benefits: Sets out power network configurations and related reliability Overview of electrical hazards and safety precautions including earth fault protection The workshop covers Motor Control Centre (MCC) design including schematics Engaging in calculations for economic and safe sizing of power cables Provides insight into motor control aspects Provides voltage drop calculations in L.V. reticulation Thermal and dynamic stress on cables during short circuit Who should attend? This workshop is relevant to the following personnel in the electrical field in mining and industrial environments: a. Design Engineers, Technologists and Technicians b. Consulting Engineers c. Design Draughtsman d. Project Planners and Estimators e. Process Plant Engineers 1. Introduction to Distribution, Transmission and Generation (D1) i. Overview of power transmission and distribution ii. International Development of Transmission Voltages iii. Power Generation Flow Sheet iv. Bulk Power Generation v. Thermal and Hydro Generation, Renewable Energy vi. 765 kv Networks vii. Power Transmission viii. Why Power Transmission, diagram of power flow to consumers ix. Developments in South Africa by Eskom x. Single Line Diagram Generation -Transmission Distribution xi. Generation and Transmission xii. Power distribution xiii. Energy exchange (wheeling), co-generation, pump-storage xiv. Bulk transmission, sub-transmission, distribution xv. Functional categories for overhead lines xvi. Localised Power distribution xvii. Distribution network will typically include this equipment xviii. Questions for delegates / from delegates 2. Network configurations and reliability (D2) i. LV & MV Networks take different forms ii. Radial Network of Feeders from MCC iii. Radial Network of Feeders in an Industrial Facility

3 iv. Radial Network with use of Bus-coupler v. Radial Network of MV feeders down the vertical shaft vi. Radial MV feeders down the incline shaft vii. Radial Network in township viii. Radial Network - ABC system ix. Radial Network ABC installation x. Line load fed from both ends xi. Ring-Main Network xii. Meshed Network xiii. Meshed Network in the city xiv. Comparison of efficiencies of distribution systems xv. Selection of system parameters:mv vs. LV, DC vs. AC, single vs. three phase, frequency 3. Earth Fault Protection in L.V. systems (D3) i. Protection against Earth Faults ii. Domestic potential casualty scene iii. Principle of E/L detection and operation iv. E/L current path v. The question is where must we install E/L protection? vi. Practical suggestion to prevent E/L accidents vii. Size of earth conductor (See DB - D12) 4. Electric shock hazard (D4) i. Electric shock, when, why and how? ii. Contact resistance iii. Effects of body Parameters on safety iv. Lightning strike v. Tolerable body currents (IEEE Std 80) vi. Frequency, magnitude, duration 5. Cable election fo MV and LV distribution (D5) i. Why insulated cables? ii. PILC cables iii. PVC cables iv. Single core unarmoured cables v. XLPE cables vi. ABC Aerial Bundled Cable systems vii. Special applications cables, oil-filled, GIL viii. Overhead Aluminium Conductors 6. Sizing of cables (D6) i. What cable size to specify and how? List of 6 aspects. ii. Low Voltage and High Voltage distribution iii. Generally the choice is between the cables or O/H lines

4 iv. Condition of installation and de-rating factors v. Permissible voltage drop on cable / method 1,2,3,4 vi. Prospective Fault current vii. Short-circuit current calculations viii. Circuit impedance calculations ix. Motor contribution to short-circuit current x. Practical calculation method for determining short-circuit currents xi. Determining short-circuit currents and breaking capacity of CB xii. Transformer impedance and fault current xiii. Parallel operation of transformers xiv. Circuit protection xv. Sizing of LV feeder cable to Distribution Board xvi. Sizing of MV cable for transformer load xvii. Permissible V.D. on cable at 1250kVA transformer terminals xviii. Conductor temperature limits xix. Trefoil Groups 7. Effect of Fault Current on Cable (D7) i. Thermal stress on cable and thermal balance formula ii. Values of factor k used in thermal balance formula iii. Continuous and intermittent cable operation iv. Dynamic stress on cable, bursting-current limitations v. Short- circuit current of the source (generator) vi. Standards and biography 8. Cables for Direct-On-Line Starters (D8) i. D.O.L. Starting Method ii. Current surge iii. Starting duty groups iv. Parameters used to produce tables v. Practical example of sizing of LV cable for motor. 9. Overhead lines (D9) i. Comparison between underground and overhead distribution ii. Structures and designs for Distribution and Transmission iii. MV overhead lines iv. Ghana, West Africa 11kV vs. 33kV v. Underground cables vi. Overhead Aluminium Conductors vii. Medium voltage distribution 10. Motor Control Centres design(d10) i. MCC dimensions ii. Colour coding of MCC iii. Ingress protection iv. What MCC cubicles may contain v. Importance of neutral conductor in MCC vi. General arrangement of MCC

5 11. MCC Schematics (D11) i. General arrangements ii. Simplified motor starter schematic iii. Three phase diagram of DOL starter iv. Example of three phase diagram of 4 cubicle MCC v. 2 nd Example of three phase diagram of 4 cubicle MCC vi. Control schematic for motor starter vii. 2 nd example of Control schematic for motor starter viii. 3 rd example of Control schematic for motor starter for larger motors ix. Variable frequency drives x. Control and termination diagram external VFD xi. Control and termination diagram internal VFD xii. Contactors xiii. MCC Incomer xiv. Thermal overload protection for motors xv. MCC Control Supply xvi. Soft starter 12. Motor Control Aspects (D12) i. Introduction to Induction motors ii. Motor ratings and performance characteristics iii. Double cage rotor for high torque iv. Resistive squirrel-cage rotor v. Starting of induction motors and speed control vi. Direct-on-line (DOL) starting of motors and overload conditions vii. Star-delta starting of motors viii. Other types of starters with reduced voltage e.g. Korndorfer ix. Electronic Soft Starter (SS) x. Rotor resistance starting for induction motors xi. Variable Frequency Drive (VFD) 13. Lighting and Small Power Distribution Boards (D13) i. Purpose of DB (Lighting and small power) ii. Importance of neutral conductor in distribution board iii. Importance of neutral conductor in carrying 3 rd harmonic current iv. Environmental rating, ingress protection v. Mounting arrangements vi. Standard colours indicating function vii. Surge arresters for lightning protection viii. Busbar ratings ix. Isolator function and ratings x. Circuit breaker ratings i. Rated continuous current (starting current)

6 ii. Rated short time current (fault level) xi. Sizing of incoming cable and switchgear xii. Calculating Volt Drop (VD) on incoming cable and sub-circuits xiii. Alternative method for calculating VD xiv. Calculation examples of VD for bulkhead, high-bay xv. Power Cable and Earth Continuity Cable sizes for various appliances xvi. Sizing feeder circuit breakers xvii. Indoor substation lighting layout