ELECTRICAL SYSTEMS

What are 2 advantages of Wood Pole Structures?

- Cost less - Easy to construct & assemble

What are 2 advantages to Geothermal generation?

1. It's a renewable resource 2. These areas are located throughout the US & around the world.

What are 4 advantages of hydroelectric generation?

1. Low operating cost 2. High production capability 3. A renewable resource 4. Does not require any fuel

What are 4 disadvantages of nuclear generation?

1. Must be located near water 2. Waste Materials 3. Non-Renewable Resource 4. Poor Public Opinion

The ground grid is a critical element of the substation and is designed to provide what 5 Functions?

1. Provide a path to the ground for lightening 2. Provide a ground for all substation equipment 3. Ensure the safety of workers in the station by limiting the ground potential differences 4. Ensure the safety of the public who may be near the fence during a fault condition 5. Provide a ground source for all lines coming in and out of the substation

What are 3 Advantages of Fossil Generation?

1. Relatively cheap fuel 2. High production capability 3. Site location

What are 2 advantages of wind generation?

1. Renewable Source 2. No Fuel Cost

What are the 4 types of transformers in over head lines?

1. Single Bushing 2. Completely Self-Protective (CSP) 3. Conventional 4. Three-phase Single Unit

What are the 2 types of transformers in Underground Residential Distribution (URD)?

1. Single Phase Padmount 2. Three-Phase Padmount

Name the 8 sources that generators typically use energy from:

1. Steam 2. Water Pressure 3. Combustion Engine 4. Combustion Turbine 5. Wind 6. Co-generation 7. Biomass 8. Resource Recovery

What are the 3 basic purposes that a substation serves?

1. Switching equipment and circuits in and out of the system 2. Voltage transmission (stepping up or stepping down voltages in the system) 3. Voltage control

What are the 4 components to calculating tensions?

1. Temp 2. Size of Wire 3. Type of Wire 4. Length of the ruling span

What are 4 disadvantages of hydroelectric generation?

1. Usually located far from the load centers 2. Cost to construct 3. Land lost to backwater 4. Impact on wildlife

Power is produced by alternating current in 3 phases per cycle. Each phase is how many degrees out from the next?

120*

In what range of volts is electricity usually generated at?

13,800 - 24,000

On a delta system each transformer requires how many phases to energize it?

2

There are three checkpoints to ensure that a regulator is in the neutral position how many must be open?

2

Lattice steel structures are typically chosen for lines energized at what?

230 kV and above

How long should you wait before tying the conductor in when stringing conductors (especially on long pulls)?

24 Hours

What does a Delta Configuration include?

3 Phases (no neutral)

What does a WYE configuration include?

3 phases and a neutral

The majority of poles used for distribution range in a length of what? and come in what size increments?

35' - 60' 5'

A combustion engine generation generator can be as small as how many kW?

5 kW

In the U.S. power is generated at how many Hertz?

60

In Wind Generation - the blades of a windmill shut off when the wind speed reaches what?

60 MPH

In Wind Generation - the blades of a windmill begin to turn when the wind speed reaches what?

9 MPH

What is the common goal of all generating facilities no matter what the type?

Generate electrical power as efficiently as possible.

What kind of generation is produced by using the heat of the earth to produce steam near the surface using natural geysers, hot springs or by pumping hot water into molten rock beneath the surface to produce steam?

Geothermal Generation

what are the two locations underground equipment can be

above-ground (pad mounted) or below ground (subsurface)

what is the advantage of using gang operated switches

all three phases can be opened at one time and must have a load break device which will allow the lines to be open under load

capacitors filter what kind of electricity

bad electricity

in a loop layout if a problem develops in the lateral HOW power can be restored to the majority of customer service by the loop

by isolating the area of trouble and closing the normal open switch feeding the customers from the other direction

capacitors can be manually or automatically controlled by what three things

clock temperature and on-off switches

capacitors introduced capacitive reactance which does what?

counteract the negative effects of the inductive reactance

the protective equipment that is used today is designed to minimize the amount of what

customers affected by faults

what will how's the fuse link that burns into when a fall occurs causing the fuse holder to fall open under normal conditions

fused cutout switches

MAST ARM OR SIDEWALK GUY

guy that is used for clearance over a sidewalk - has a rigid conduit mounted 10'-15' down the pole

HEAD GUY

guy wire attached to the top of a pole to a point below the top of the adjacent pole, usually on a steep slope

How are the primary winding of the CT's connected?

in a series with the conductor carrying the current to be measured or controlled

how is power supply to the customer in a loop layout

in the loop from either direction

commercial and Industrial companies lose large amounts of what even during relatively short outages

money

What are shielding or static wires?

one or two smaller wires attached to the top of the pole and grounded to provide a path to the ground for lightening strikes and dissipate any static or induced voltage.

some faults such as a car hitting a pole or a limb or tree falling through and breaking the line are considered what

permanent

given the importance and convenience of electricity what is crucial

service reliability

most faults occur due to nature such as Birds squirrels and tree limbs brushing against the line these are what

temporary

describe lightning arresters connections

the top side is connected to the face and the bottom side is connected to the ground source

a riser is a term used to describe what

the transition from overhead to underground and in some cases from Underground to overhead

BUNDLED

the use of more than one conductor is used to form a single phase - usually 2-4

what do reclosers do

they are devices that can open and close automatically reintroducing the circuit up to four times

What is a disadvantage of Tubular Steel Poles?

they are much more expensive (sometimes 2x more) than wood poles.

what are capacitors used for

to improve the efficiency of the circuit

Why is properly sagged wire higher in winter and lower in Summer?

wire contracts during cold weather and expands during hot weather

before working on a disconnected capacitor what is the OSHA requirement you must follow

you must wait 5 minutes after the switch has been opened

What are the most complicated, reliable and some time most economical method of distributing electric power?

Networks

The overall power system consist of 4 basic "sub-systems"; what are they?

1. Generation 2. Transmission 3. Substations 4. Distribution

What are 2 advantages of nuclear generation?

1. High production capability 2. No airborne pollutants

What are the 3 methods of electrical generation most commonly found in utility systems?

1. Fossil Generation 2. Hydro Generation 3. Nuclear Generation

What are the 4 types of substations?

1. Generation 2. Transmission 3. Sub-transmission 4. Distribution

What are the two most common types of conductors?

-ACSR -AAAC

What are insulators made from? (3)

-Glass -Porcelain -Polymer

What are Static wires made of and what are their purpose?

-High Strength Steel -act as a shield to protect the energized phase conductor from lightning strikes

What are the 3 types of insulators (not what they are made from but their TYPE)?

-Pin-type -Post - Type - Suspension Type

Primary Voltage is the high side of a distribution line, it is supplied to a distribution line by what? And is used for what?

-Substation Transformer -distribute electricity throughout a service

Substation transformers connect the transmission system to what and do what?

-The primary distribution -may effect a voltage transformation of 161kV down to 46kV

Secondary voltage RUNS where? (3)

-pole to pole -pole to under ground pedestal (overhead) -pad mount to pedestal (underground)

The actual values of primary and secondary voltage vary depending on what? (2)

-the design of the distribution system -the requirements of customer it serves

What are 4 disadvantages of wind generation?

1. Construction Cost 2. Velocity of wind or no wind 3. Environmental concerns (birds flying into blades) 4. Limited Capacity

What are 3 Disadvantages of Fossil Generation?

1. Environmental Pollutants 2. Non-Renewable resources 3. Cost for Fuels to be delivered

DOWN GUY

A guy wire that attaches to the top of the pole and extends to anchor rod at ground level

What is an extension of a feeder that carries primary distribution voltage portions of a service area that are not immediately adjacent to the feeder?

A lateral

As load changes continuously what must the generation of electricity do?

Also change to supply that changing load

What forms the common collecting point for receiving and redistributing the power?

Bus Conductors

How is power generated in a hydro plant (hydroelectric generation)?

By water flowing through a turbine, which is coupled solidly to a generator

On wood poles, what would be the result of improper or lack of bonding?

Can cause pole fires due to leakage of currents (lightening can also cause this)

What type of generation is most easily identified as a generator?

Combustion Engine Generation

What is the most popular type of transformer on overhead lines and why?

Conventional - it can be used for single phase services or banked together for three phase services.

What reduces the current levels in the lines and are connected to relays that allow breakers to open under over-current and fault conditions?

Current Transformers (CT's)

Some poles need to be set deeper. At what time would you set poles 1' deeper?

Dead end poles or angle poles

Other than WYE, what is the other type of primary configuration?

Delta

Which configuration requires a single voltage between two phases?

Delta

Wind, Dirt, Sand and snow blowing across transmission lines causes what?

Friction - creating static electricity

Generation facilities are usually located near or far from the load centers?

Far (long distances)

What does a breaker do?

Interrupts current under normal load conditions and under short circuit or fault conditions when the flow may be many times greater than normal.

Bundled conductors are often used for transmission lines that carry what?

Large amounts of load

Name the type of structure that uses some type of angle steel bolted together to form a lattice arrangement?

Lattice Type Steel

What type of structure is usually put together by a specialized crew due to its number of parts and time consuming construction?

Lattice Type Steel

Transmission lines are typically long and subject to what?

Lightening strikes, wind, dirt, sand, snow

Public opinion is critical in site location and style of substation, what may be done in high profile locations to approve appearance?

Low structure profile, decorative fencing and attractive landscaping

Where are hydroelectric generation facilities typically found?

Mountainous Regions

How is pole depth calculated when on normal soil? Solid Rock?

Multiplying the length of the pole by 10% then adding 2 inches when on normal soil On solid rock just use 10% of length

About 20% of today's energy is produced by what kind of generation?

Nuclear

Typically a primary feeder consist of 3 individual phase wires, either underground or overhead: each wire carries how many phases of a three-phase feeder?

One

What step's down the circuits high voltage to a desired secondary voltage?

Potential Transformers

What do lightening arresters ?

Protective devices that prevent damage to equipment by limiting surge voltages due to lightening strikes equipment faults or other events.

The substation is an integral part of the power system, what does it do?

Serves as a juncture point of lines and other system equipment

What are low voltage BUT run from pole to the customer on overhead systems and pedestal to customer on underground systems?

Services

What type of generation uses an array of Mirrors to direct sunlight on a specific location such as a water tank to produce steam?

Solar Generation

What type of generation uses special cells to produce and store electricity when sunlight strikes them?

Solar Generation

there is no what in a cable

Steel

What carries medium size blocks of power from the sub transmission substation to the metropolitan area and is not part of the main transmission grid?

Sub transmission Voltage

All transmission lines throughout north america (US & Canada) are tied together and called what?

The Transmission Grid

What can the Transmission Grid be compared to?

The US interstate system

SPAN GUY

a guy wire attached to the top of one pole with energized conductors to the top of another pole with energized conductors

What is the DC battery's purpose in a control house?

To control key equipment if power is lost at the substation, they are the way to open the breaker in case of a fault on a line

Why do we need to measure power?

To determine when abnormal amounts of voltage or current are present in order to operate protective devices used to disconnect lines and equipment

What are current and potential transformers used for?

To provide a reduction in current or voltage so that the power can be measured.

What is the basic function of the transmission system?

To transmit large amounts of bulk power over long distances.

what cost more? overhead or underground Distribution Systems

Underground

PUSH GUY

a pole that is used as a brace (to push up another for a brace)

When will wire that has been properly sagged be higher? (Season)

Winter

Transmission lines operating at 161 kV and below may use what types of constructions? (Pole structures)

Wood Pole Structures

What are the most popular choice in poles for power line construction? What kind are being used for street lighting now?

Wood Poles Steel, Concrete, Fiberglass

What is the most common type of primary phase and why is it called this?

Wye - so named because of the shape of a Y)

STUB GUY

a guy wire attached to the top of a pole with energized conductors to the top of another pole without energized conductors