Electric Grid and Power Distribution Quiz

Electric Grid

• Electric grid is the network through which power is generated, transmitted, and distributed.
• Components of electric grid: Generation, Transmission/Distribution, Consumption

Key Components of Electric Grid

• Generating Plants: produce electricity
• Transmission Lines: high-voltage lines that carry electricity from power plant to substation
• Substations: step up or step down voltage to match transmission and distribution requirements
• Distribution Lines: low-voltage lines that carry electricity from substations to end-users for residential and commercial use

Types of Electric Grid

• One-way dialogue: Localized Power Generation
• Two-way dialogue: Smart Grid

Electric Power Industry in the Philippines

• Three grids: Luzon, Visayas, Mindanao
• Examples of transmission lines in the Philippines: 500kV, 350 kV, 230kV, 138kV, 115kV, 69kV
• Republic Act No. 9136/Electric Power Industry Reform Act (EPIRA) Law: sought to restructure the electric power industry by privatizing the generation, transmission, distribution, and supply of power sector

National Transmission Corporation (TRANSCO) and National Grid Corporation of the Philippines (NGCP)

• TRANSCO: maintains and manages the entire power transmission system that connects the different power plants to the electric distribution utilities across the country
• NGCP: ensures that the country's transmission assets are in optimal condition to convey safe, quality, and reliable electricity

Distribution System

• Part of an electric system after the transmission system that is dedicated to delivering electric energy to an end-user
• Types of Electric Power Distribution Systems:
  • According to the nature of the supply: AC Distribution system, DC Distribution system
  • According to a type of connection: Radial system, Ring system, Interconnected system
  • According to a type of construction: Overhead system, Underground system

AC Distribution System

• Primary Distribution System: operates at voltages somewhat higher than general utilization and handles large blocks of electrical energy than the average low-voltage consumer uses
• Secondary Distribution System: includes the range of voltages at which the ultimate consumer utilizes the electrical energy delivered to him

Overhead and Underground Distribution Systems

• Overhead distribution System: conductors are mounted on wooden, concrete, or steel poles
• Underground distribution System: conductors are placed under the surface of streets or sidewalks
• Two methods of installing underground distribution systems: Duct System, Direct Burial System

Electric Meter and Panel Board

• Electric Meter: an instrument used by the utility company to measure and record electrical energy consumed
• Panel Board: a device that consists of a sheet metal box, called a cabinet, and a cover that encloses and conceals the panelboard interior to limit access to power distribution components

Overcurrent Protection

• Fuses: work as a piece of metal that melts down when overheated
• Circuit Breakers: work by operating a switching mechanism when an overflow of electricity is detected

Lighting and Electrical Devices

• Lamp: a device that generates light (source)
• Bulb: the glass portion of a lamp that encloses and protects the working parts of the light source
• Luminaire: a complete lighting unit, which consists of a lamp (or lamps), lamp socket(s), any lenses, refractors, or louvers, any ballast (or ballasts), and the housing
• Light fixture: includes the structural parts of a luminaire including any lenses, mounting supports, wiring, and ballasts, but does not include the lamps

Lighting Measurements

• Luminous flux: the measure of the perceived power of light expressed in lumens (lm)
• Lumens: measure of the total amount of visible light (to the human eye) from a lamp or light source
• Luminous intensity: measure of the radiant power emitted by an object in a given direction and is dependent on the wavelength of light being emitted
• Candela: a measure of power emitted from a light source
• Luminous efficacy: formula of LPW (Lumens per watt)
• Color temperature: way to describe the light appearance provided by a light bulb
• Color Rendering Index (CRI): a measurement of how natural colors render under an artificial white light source when compared with sunlight

Electrical Devices

• Outlet: the location in a branch circuit where electricity is used
• Receptacle: a female connecting device with slotted contacts
• Plug: a male connecting device that has two or more prongs that are inserted into a receptacle to connect to an electrical circuit
• Switches: a device placed between two or more electrical conductors in a circuit to safely and intentionally open or close the circuit or to redirect the path of current in a circuit
• Types of switches:
  • Single-Pole Single-Throw SPST
  • Single-Pole Double-Throw SPDT
  • Double-Pole Single-Throw DPST
  • Double-Pole Double-Throw DPDT
• Automatic switches: deactivate a circuit after a preset time period has lapsed
• Dimmer switch (SD): a device in the electrical circuit for varying power to a circuit
• Time clocks: can be used to control the time period that a piece of equipment or a lighting installation operates
• Photocell: controls sense light and open or close a circuit with the presence of light
• Occupancy sensors: control a lighting or equipment installation by sensing occupants in a space