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DAY 1 Session 1 - Introduction: This session consisted of setting up a single line diagram with ETAP software. Drag and drop electrical devices on the screen and then add device characteristics. Software shortcut ?(1) hold the space bar and then you can move the screen, (2) hold the control key and zoom in and out with wheel of the mouse. Session 2 - ETAP Libraries and Load Flow Modeling and Analysis. This session is about using and adding to ETAP libraries for load flow modeling. This session explains the 3-D database which is using revisions, presentation, and configurations. DAY 2 Session 3 - Load Flow Modeling/Analysis and Panel schedules The load flow analysis will help the engineer size cables, switchgear and MCC buses, and transformers and perform voltage drop calculations. The program is set for 5 % voltage drop from source to load. Different types of electrical loads 1) Constant Power Load (motors), 2) Constant Impedance Load (static loads) 3) Constant Current Loads (UPS, DC systems). Solutions to overvoltage or undervoltage: change transformer taps or use capacitors. Sample output report
Session 4 - Short Circuit This session shows how to perform short circuit calculations. There are two types: three phase fault and ground faults. Most of the time, the worst case is 3-phase fault. Short circuit calculation is necessary to protect the equipment such as switchgear, MCCs, transformers, and etc. The 1/2 cycle calculation is used for the short circuit 3-phase fault, but for setting relays and high voltage equipment ratings 1-1/2 to 4 cycle study is required, see chart below. The calculation compares the calculated 3-phase fault with the manufacturer's bus bracing for Swgr/MCC, compares LV circuit breaker interrupting capability ratings, and compare HV CB with closing and latching capability and interrupting capability. Sample output report
DAY 3
Session 5 - Relay Coordination Summary: Using this module the engineer runs different scenarios with tie breaker and main breaker open and close. Adjust the settings of protective devices so down stream breaker trip first. TCC will be created for the engineer to evaluate the relay/fuse coordination. The objective: 1) To determine the ratings and settings of fuses, breakers, relays and etc 2) To isolate the fault or overload conditions Session 6 - Arc Flash
Regulating Authorities for Arc Flash •OSHA 29 CFR 1910.132 (d) requires employers to assess the workplace to determine if hazards are present, or likely to be present and select and have each employee use the types of PPE that will protect them. •OSHA 29 CFR 1910.333 Requires employees who are exposed to electrical shock hazard to be qualified for the specific task that they are performing and use the appropriate PPE. Definition of Area concerning Arc Flash 1 Limited Approach Boundary: A shock protection boundary not to be crossed by unqualified persons unless escorted by qualified personnel. 2 Restricted Approach Boundary: A shock protection boundary to be crossed by only qualified persons. Shock protection is required. 3 Prohibited Approach Boundary: A shock protection boundary to be crossed by only qualified persons. The use of techniques that may require direct contact with energized equipment.
DAY 4 Session 7 - Motor Starting Summary: Two types: static motor starting and dynamic motor starting. Usually dynamic motor starting is for 1500HP and larger. Most motors are NEMA B type. Sync motor and Induction start are similar for this type of study. Most studies assume all loads are on and starting the largest motor, if the voltage dip is too large, greater than 20 percent then the other contactors will drop out. Session 8 - Transient Stability Analysis Summary: Transient stability study checks how the voltage and frequency fluctuation affects the electrical system and motors. When a fault occurs or large motor drops out the system may become unstable and then critical loads dropout, potential black out, damage motors. Results of the study: CFCT (Critical Clearing Time) is calculated in order to help evaluate the stability of the system. Solutions: bus transfer, load shedding (under/over freq, under/over-voltage) and etc. DAY 5 Session 9 -DC System
Session 10 - Harmonics Power Quality problems caused from UPS, VSD, Inverters, Arc furnaces, Battery Chargers, Non-linear loads. (IEEE 399, brown book). If the device (transformer) or area on the single line diagram has no grounding than no harmonic order of 3,6,9,12,18.21 will show up. PCC (point of common coupling) per IEEE 519 is 5 % voltage distortion and 3% of harmonic distortion. Possible fixes are single-tuned harmonic filter, by-pass filter, high-pass filter (damped) or (undamped), also change VSD to 18 pulse or higher.Sample output report with issues sample report with issues fixed Duct bank Ampacity: Methods: Uniform-temperature cable ampacity calculation, Uniform-ampacity cable ampacity calculation, steady-state temperature calculation. Cable alarm setting is set at 90 deg C. Sample output report ˇˇ |
