Thursday, August 24, 2017

Basic Introduction to Electrical Engineering department of Design Company

ELECTRICAL DISCIPLINE ORIENTATION 

ROLE OF ELECTRICAL DISCIPLINE

Major areas of work (This post is written mainly with  Oil & Gas sector)
          Oil & Gas
          Substation (Utilities & infrastructure)

1.       Make Power Supply arrangement
o        Design incoming power supply system and associated equipments
o        Design Overhead Transmission Line (OHL), Cables, Switchyard, Switch-rack, etc.

2.       Design Power Supply Distribution system
o        Design substations and associated equipments
o        Create voltage levels, as required by the loads
o        Make reliable/emergency power supply arrangements

3.       Distribute power to individual loads & consumers
o        Mechanical equipments such as pumps, compressors, electric heaters, etc.
o        Instrumentation equipments such as DCS/ESD, field instruments, motorized valves, etc.
o        Pipeline equipments such as Catholic Protection system, hydraulic power units, etc.
o        Prepare cable tray, cable trench and cable routing layouts
o        3-D modeling of cable tray/trench, local control stations, etc.

4.       Other Activities
o        Lighting system design for the plant, substations and buildings
o        3-D modeling for lighting fixtures (if required by client)
o        Earthing system design for substation, plant & Instrumentation
o        Catholic Protection design coordination for pipelines
o        Lightning Protection design for tall structures
o        Conduct Electrical Design Review and SAFOP studies
o        Participate in Project Design Review and HAZOP studies
o        Prepare Material & Purchase Requisitions, Datasheets, TQ, TBA and Vendor document review of Electrical equipment
o        CTR preparation and EPC bidding support
o        Site visits for data collection
o        Meeting with clients and vendors

5.       Provide input to other disciplines
o        Electrical building and equipment details to Civil for foundation /  architectural design  and to Mechanical for HVAC design
o        Electrical equipment details to Piping for plot plan
o        Electrical equipment datasheets to Mechanical for MR/PR
o        Power supply details to Instrumentation
o        Cable trench, duct bank, support data to Civil and Piping
o        Day to day coordination for Inter Disciplinary documents checks
For Completing the deliverables Electrical departments also required input from other departments as below ;

Inputs required from other disciplines
PROCESS:
o        Equipment list, load details and approx. kW ratings
o        P&ID for motor/heater control requirements
o        Hazardous Area Classification drawings for equipment selection
PIPING
o        Plot plan for starting layout drawings
o        GA drawings for finalizing cable tray & support arrangement
o        3-D model for cable tray/trench routing and lighting
o        Isometrics for Electric heat tracing design
CIVIL
o        Building design for floor cutout finalization
o        Structural design for cable tray & lighting fixture supporting
o        Soil investigation report, foundation & paving details for earthing
o        Underground detection survey report for brown field areas
PIPELINE
o        Pipeline details for CP system scope of work
o        Plot plan for starting layout drawings
o        GA drawings for finalizing cable tray & support arrangement
MECHANICAL
o        Vendor data for equipment sizes and rating confirmation
o        HVAC ducting layouts for finalizing cable tray, lighting fixture supports
INSTRUMENTATION
o        UPS & non UPS load details and approx. kW ratings
o        Auxiliary/Control Room Equipment layouts for earthing
o        Power cable requirement for including in cable MTO
o        Type of earthing systems required
DOCUMENT CONTROL & QUALITY CHECKS
o        The deliverables produced by Electrical Discipline are checked internally as per Quality Procedure – Document Control
o        Document No. TR-AQ-Q-007
o        The deliverable are then circulated for IDC as per “Deliverable Responsibility Matrix”  prepared by the companies individually.

DELIVERABLES – 

1.       Single Line Diagrams  (the most important deliverable from Electrical department)

A Single Line Diagram (SLD) is one line representation of power flow scheme for a particular substation/plant/equipment and shows how the voltage is converted from one level to another and distributed to various consumers/loads.
What does a SLD contains?
            Source of power,
            One lines representing the power flow, cables & connections,
            Voltage conversions equipments,
            Distribution equipments,
            Protection & metering equipments,
            Grounding/Earthing equipments, and
            Loads/consumers
Some of the other type of SLD are:
Protection & Metering, Lighting, etc.
one glimpse of this diagram is below

Second most important deliverable is :

2.       Electrical Equipment Layout (generally of a substation)
                It  shows the plan and sectional view of electrical equipments located inside,  outside and on the             roof of the building. It indicates the horizontal and vertical clearances between the equipments      considering safety, accessibility, maintainability and aesthetics.
                It also indicates other rooms, such as battery room, auxiliary room, etc., within the building and                internal equipment arrangement.
                One of the main purpose of equipment layout is to provide input to Civil for carrying out              building and architectural design work.
It also provides input to Mechanical for HVAC system design and Instrumentation for their design work. (Auxiliary room, fire alarm, etc.)

Other Deliverable are DRAWINGS & DOCUMENTS AS LISTED BELOW:

3.       Protection & Metering Block Diagrams
4.       Switch yard / Switch rack / Equipment layouts
5.       Cable Routing Layouts (Tray, Trench and Cable)
6.       Lighting Layouts
7.       Earthing & Lightning Protection Layouts
8.       OHL Route Plan and Profile drawings
9.       Power and control schematics
10.   Standard installation drawings
11.   The other major deliverable produced by Electrical are:

DOCUMENTS PREPARED BY ELECTRICAL

12.   Load List
13.   Equipment Sizing (Transformer, EDG, UPS, CT/PT, Cable, etc.)
14.   Earthing and Lighting Protection Calculations
15.   Indoor & Outdoor Lighting Calculations
16.   Protection relay setting and coordination
17.   System studies (LF, SC, VD, MS, etc)
18.   Electrical Design Review and SAFOP studies
19.   Adequacy checks
20.   Cable & Interconnection Schedule
21.   Signal List
22.   Cable and Bulk MTO
23.   MATERIAL REQUISITIONS AND DATASHEETS:
24.   Transformer & NER
25.   Bus duct
26.   MV & LV Switchgear & Distribution Boards
27.   Relay Protection and Control Panels
28.   AC/DC UPS, Emergency DG
29.   MV & LV Motor
30.   Variable Frequency Drives / Soft Starters
31.   MV, LV Power, Control & Earthing Cables
32.   CP System & Electrical Heat Tracing
33.   OHL & Switchyard Equipment
34.   Package Equipment
35.   SOFTWARE USED BY ELECTRICAL
36.   Electrical discipline uses the following software tools:
37.   For Short Circuit calculations, Load Flow studies, Voltage Drop calculations, Motor Starting studies, Relay Protection Coordination, and Earthing System Design.
38.   ETAP
39.   EDSA
40.   SKM Power Tools
41.   CYME (planned to be purchased soon)
42.   OHL design
43.   PLS CADD
44.   Lighting System Design
45.   Calculux
46.   Chalmlite, and other vendor software
47.   Battery Sizing
48.   Alcad
49.   Battsize, and other vendor software

ELECTRICAL EQUIPMENT 
  • TRANSFORMER
          Used for changing voltage level up/down
          Generally, incoming power supply is available at higher voltages since power transmission is carried out at higher voltage for reducing the current and transmission losses.
          Therefore, transformers are used for stepping the voltage down to consumer/load levels.
          In case of power plants, transformers are used to step the voltage up.
  • NEUTRAL GROUNDING RESISTOR
          Used for limiting earth fault current
  • SWITCHGEAR
          These are the mechanisms used for switching the power ON and OFF and protection (interruption of fault currents for safety)
          Includes isolators, fuses, circuit breakers, etc. and are located either indoor or outdoor.
The type of switchgear can be Air, Oil, Gas or Vacuum depending on voltage level and application
  • BUS DUCT
          CU/AL bus bars are enclosed in steel/aluminium enclosure
          Used in place of cables for connection between transformer and switchgear, where current values are very high.
  • HV & LV MOTORS
          Used as prime mover for pump, compressor, etc.
          Generally, 180kW and below rated motor are Low Voltage (415V)
          250kW and above rated motors are High Voltage (6.6kV, 11kV)

  • HV POWER CABLES
          Cables are 1-Core or Multi-core (3 or 4)
          Typical insulation type used – XLPE
          Armour for mechanical protection – Aluminium or Steel Wire
  • BATTERY BANK 
  • RELAY & CONTROL PANEL               
  • SWITCH RACK 
  • CP TRANSFORMER RECTIFIER 
  •  MOTORIZED VALVE 
  •  EARTHING PIT 
  •  PROTECTION RELAY 

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