Electrical Grid 2: Chapter 3 - Introduction to Smart Grid - Possible Test Questions - WEEK 9

Question 1

Department of Energy defines the term “smart grid” as:

Answer 1

• incorporation of the concepts, philosophies, and technologies that enabled the Internet, into the electrical grid.

Question 2

Peak load refers to:

Answer 2

• the time of day when the demand for electricity is at its highest, typically late afternoon and early evening hours.

Question 3

Cascading:

Answer 3

• a condition in which an outage on a circuit causes outages on interconnected circuits because the interconnected circuits are not able to handle the additional load.

Question 4

When is cascading is most likely to occur?

Answer 4

• During the time of day when demand is at its peak.

Question 5

The strain on the grid during peak loading and the effects of cascading power failures best explain:

Answer 5

• why we need a smarter electrical grid.

Question 6

Modernized:

Answer 6

• the most current technologies that help to combine electrical supply and communications in a manner that equipment can be synchronized together and operate in unison.

Question 7

Intelligent:

Answer 7

• Equipment is able to use information to make quick decisions and execute the appropriate functions that maintain safe and reliable electric service.

Question 8

Efficiency:

Answer 8

• refers to everything from power quality to streamlining operational processes and procedures.

Question 9

Renewable:

Answer 9

• the grid is able to accept and rely on power generated from more renewable resources such as wind, solar, and hydro-electric, reducing the dependency on pollutant emitting generators.

Question 10

Automation:

Answer 10

• Equipment is able to sense and automatically react to situations without the need for a human interaction.

Question 11

Remote Control:

Answer 11

• The system operators can operate key equipment when needed from remote locations via any means of communication necessary. SCADA (Supervisory Control And Data Acquisition) is a common type of remote control method used in system operations.

Question 12

Self-Healing:

Answer 12

• Uses automation to sense disturbances on the system, and automatically trigger key operations to keep more customers in service.

Question 13

Resilient:

Answer 13

• strong enough to handle major disturbances without experiencing cascading.

Question 14

Secure:

Answer 14

• resistant to unauthorized operation including cyber attack.

Question 15

Demand Side Management:

Answer 15

• methods of reducing consumption of electricity by customers, especially during times of peak loading.

Question 16

Bi-directional energy flow:

Answer 16

• Power can flow through the circuits and equipment from either direction. For example, a smart recloser can recognize that current is flowing the opposite direction and switch its protection scheme accordingly.

Question 17

Islanding:

Answer 17

• When distributed generation is adequate enough to handle the load of a given portion of the electrical system on its own (without dependence on the main grid) a condition known as “islanding” occurs. Islanding refers to a portion of the electrical system that can operate independently from the main grid.

Question 18

Peaker plants:

Answer 18

• generators that increase operation only during the peak loading times of day, if needed.

Question 19

Rotating a magnetic field produces:

Answer 19

• AC and there are many ways to make something rotate.

Question 20

The reservoir formed by a normal hydro-electric dam provides:

Answer 20

• The water source and is referred to as the lower reservoir.

Question 21

Molten Salt:

Answer 21

• A form of thermal energy storage that is normally combined with solar thermal generation.

Question 22

Batteries are a typical form of:

Answer 22

• electrical storage

Question 23

Some of the newer methods of storage include:

Answer 23

• Compressed air and flywheel technology.

Question 24

Compressed air is:

Answer 24

• A viable option for storage in caverns, abandoned mineshafts, and empty gas reserves. Compressed air is forced into the cavity or storage area by a large-volume compressor and released through a turbine when needed.

Question 25

Flywheel Technology:

Answer 25

• Flywheel technology produces electricity by rotating a rotor at a very high speed, and then using the rotating energy to produce electricity.

Question 26

Conductors such as ACCC (Aluminum Conductor Composite Core) are designed:

Answer 26

• to allow much more current to flow at higher temperatures than the same sized conductor of All Aluminum or Aluminum Conductor, Steel-Reinforced.

Question 27

Management Systems Phasor Measurement Units, (also called syncrophasors):

Answer 27

• Are strategically located in substations that interconnect the generators and transmission systems together. They can check the phase angle on the voltage and current waves, as often as 30 times per second, and automatically trigger the operation of key substation equipment such as capacitors and reactors to operate when there are disturbances to the phase angles.

Question 28

Dynamic Line Loading:

Answer 28

• A philosophy that allows the real time conditions surrounding conductors to be monitored. Conductor ampacity ratings, wind speed, ambient temperatures, and even conductor temperature are collectively used to give system operators more data to help them make critical decisions regarding the transmission circuits.

Question 29

One major advantage of dynamic line loading:

Answer 29

• Is line thermal monitoring, which allows the operators to view conductor temperature using infrared imaging.

Question 30

Optical Ground Wire (OPGW):

Answer 30

• A shield wire installed at the tops of structures.
• The shield wire offers lightning protection for the supply conductors, but can also contain fiber optic cables that can be used for high- speed communications.

Question 31

Micro grids can form when:

Answer 31

• larger portions of circuits begin islanding.

Question 32

The distribution components and devices have to be able to accommodate bidirectional energy flow. For switching type equipment like cutouts, reclosers, and gang switches, they’ll have to meet two objectives:

Answer 32

• Provide a means for isolation and sectionalizing as per their design
• Change their operating parameters to the opposite direction until the system returns to normal

Question 33

distribution components are strategically installed on the circuits where they:

Answer 33

• can best perform their functions.

Question 34

Reclosers:

Answer 34

• Reclosers are circuit breakers. They can be installed at the substations or out on the circuits. When a fault occurs, the recloser will re-energize the circuit to determine if the fault is temporary or permanent. If the fault is permanent, the recloser will “lock out” or remain off until the repairs are made. If the fault is temporary, the recloser will re-energize the affected line and reset itself to normal operation. The reclosing feature can be disabled.

Legacy:

• Hydraulic operated
• Use oil or vacuum to extinguish the arc
• A lever can be operated to open or close the contacts
• A separate lever can be operated to disable the reclose feature
• Some are equipped with a counter so that the number of operations can be monitored

Smart:

• No oil
• Vacuum is typically used to extinguish the arc
• Electronically controlled
• Hot-line tag can be used to disable reclose, unauthorized operation, and change the settings to be more sensitive for energized work downstream
• Can be set with multiple functions such as single phase reclose-three- phase trip
• Can be operated with SCADA
• Can limit the fault current that the system can deliver to the fault, reducing the stress on the system
• Provides real time data on each phase and can operate in bi-directionally for self-healing
• Records operational history

Question 35

Switches:

Answer 35

• Switches have always been known for one simple function: open and close. Of course, the installation of a switch is very strategic in nature, as it can provide a means of gang-operated disconnection at specific points in the circuit. In fact, many are placed as normal open points in between two feeders, allowing options for alternate feeds. They do not interrupt fault current, but they are designed to interrupt a significant amount of continuous line current. Many companies refer to them as GOAB, or Gang-Operated Air Break, referring to the operational characteristics of the switch.
  Legacy:
• Gang-operated,
• Equipped with a handle allowing the lineworker or troubleman to open or close the contacts,
• Can interrupt continuous line current,
• Handle can be locked to prevent unauthorized operation.
  Smart:
• Gang-operated,
• Equipped with electronic controls allowing them to be operated remotely or automatically,
• Provides real-time data on each phase,
• Can be automated as part of a self-healing scheme,
• Some are equipped with SF6 interrupters allowing for high current interrupt ability,
• Can be installed in coordination with a recloser, allowing a permanent fault to be isolated from a recloser, like a sectionalizer.

Question 36

Cutouts:

Answer 36

Cutouts are a reliable single phase switching device that can incorporate the functionality of a switch with the protection of a fuse. Fuse links are universal, meaning they can be used in different size cutouts. They come in a variety of speeds and ampere ratings so that fuses can blow fast or slow depending on the needs of the lines or equipment they protect. Some cutouts use solid-blade doors providing switching capability only. The opening contacts can be in loadbreak or non-loadbreak configurations.

Legacy:
- Can be universal fuse link or solid blade,
- Fuses are available in different speeds so that they can be coordinated
with other protective devices,
- Can be used in conjunction with current limiting fuses providing an added
degree of overcurrent protection,
- Can be loadbreak or non-loadbreak.

Smart:

• Tripsavers, Fuse savers,
• Fits right in a conventional cutout,
• Single phase recloser,
• Reduces the momentary interruptions caused by feeder reclosers,
• Can be coordinated to operate as a sectionalizer,
• Doesn’t trip from load pick-up switching,
• Electronically control powered by the line,
• Display can indicate how much real-time load is on the device

Question 37

Capacitors:

Answer 37

• Capacitors are normally banked together to provide capacitive load on a line to counteract the negative effects of inductive loads. There are two types of capacitor banks: fixed and switched. Fixed capacitor banks are more of the legacy style, but are still an inexpensive option for portions of electrical circuits that experience constant inductive loading. Switched capacitors lean more towards the smart style because they can operate automatically when the loading changes. For example, businesses that operate 8:00 am to 5:00 pm tend to experience more inductive loads during the business hours of the day, but not as much outside of normal business hours. A fixed capacitor would create too much capacitive load outside of business hours; a switched capacitor can switch on and off in sync with the conditions.
  Legacy:
• Fixed capacitor bank,
• Energized all the time to correct power factor for those localized loads that experience continuous inductive reactance,
• Protected by fused cutouts to isolate it from the circuit if a cell fails.
  Smart:
• Switched capacitor bank,
• Can be programmed to operate based on various triggers such as temperature, time-of-day, or power factor.
• Uses switches to connect/disconnect the capacitor to the line without the need for human interaction.
• Can operate in unison with other switched capacitors based on the conditions of the overall system.

Question 38

Regulators:

Answer 38

• Regulators have been automated in their functionality for a long time. They can sense when the voltage is too high or too low on the circuit, and adjust the voltage to the proper levels to protect voltage sensitive equipment and customer facilities. The smarter regulator uses smarter controls, which provide a variety of options that help to correct the voltage as well as extend the life of the regulator’s tap changing mechanisms. One energy conservation method being employed with regulators is called “conservation voltage reduction” which is employed during peak loading. For load tap changing transformers in the substations and voltage regulators on the circuits, the taps are purposely lowered to low-end of the required service voltage range of 114-126 volts which can actually reduce demand on the system.
  Legacy:
• Manually operated controls on site,
• Each regulator in the bank has its own control,
• Regulators can adjust based on circuit conditions.
  Smart:
• Controls can be operated manually or remotely, but the regulator controls make the regulator automated,
• Controls can use bandwidth, time delay, and various other functions to
  allow short-duration voltage issues to correct themselves, extending the life of the taps,
• Newer controls allow the operation of multiple units through one control,
• Can be programmed to operate with Conservation Voltage Reduction schemes,
• Can function bi-directionally.

Question 39

Power Line Sensor Technology

Answer 39

• Whether a circuit uses the legacy components or the smart components, there are still some things that can be done to implement smart grid technology. Fault indicators and sensors can be quickly installed on the conductors, providing valuable data for troubleshooting and localized power quality disturbances. Some sensors can communicate data to a wireless transmitter/receiver that can get the data to the utilities and/or system operators.

Question 40

With a smart home, the homeowner will play a more active role in:

Answer 40

• Their energy consumption.

Question 41

The smart home is a communication network that allows:

Answer 41

• a customer to remotely connect and control many automated digital devices throughout the home. This will allow the customer to play a more active role in their energy consumption. Customers will be able to monitor, manage, and control their energy usage through home-area-display units, the homeowner’s computer, and cellular phones. This is referred to as “demand-side management.”

Question 42

Customers will be more aware of their energy usage and the times of day that will be:

Answer 42

• the most cost-effective to use electricity.

Question 43

Benefits to the Utility:

Answer 43

• Utilities are able to implement time-of-use rates during peak demand to lower operating costs.
• Smart appliances and heating/air conditioning can be programmed to reduce usage during peak loading.
• Utilities can use the excess electricity generated from the customer’s distributed generation.
• Utilities can use distributed generation to reduce load during peak demand by having the customer switch to their distributed generation for their power source.

Question 44

Benefits to the Customer:

Answer 44

• Able to monitor energy usage in real time instead of waiting for a monthly bill
• Able to adjust the settings on their appliances and HVAC controls based on time-of-use pricing
• Able to use distributed generation to save money during peak rates

Question 45

Security:

Answer 45

• Security of the smart meters and the smart home is important. Smart meters and systems are subject to hacking, and with any computerized system, security is important.

Question 46

Power line carrier:

Answer 46

• has a communication technique and protocol through the power lines which is very proprietary and difficult to decode even if a person has the right equipment. RF Mesh and WAN utilize advanced encryption codes and other security layers to make the system as secure as possible.

Question 47

As the smart home starts to become more common place, the utility workforce will need to be familiar with how smart homes function. This will benefit the utility workforce in troubleshooting situations and in day-to-day contact with customers. The smart home includes the following components:

Answer 47

• Home-Area-Network with a smart meter
• Home-Area-Network without a smart meter
• Smart Appliances
• Smart Lighting
• Plug-In Hybrid Vehicles & All Electric Vehicles
• Distributed Generation

Question 48

The smart meter will relay:

Answer 48

• Any price changes to the home-area-display unit which will then communicate with the smart appliances.

Question 49

One way the smart meter will communicate with the homeowner is:

Answer 49

• through a home-area-display unit.
• The unit will communicate with the smart meter through a Zigbee wireless connection much like WIFI that is currently used with computers.

Question 50

Depending on the capabilities of the hardware installed in the smart meter or the home-area-display unit, the utility can

Answer 50

send a message to the customer’s smart appliances alerting them of the price change. The smart appliances can then adjust their settings accordingly, and the customer can be sent an alert when the settings are going to change.

Question 51

Some companies give the customer the option of buying

Answer 51

Smart Plugs which give them the ability to plug in appliances individually and see their consumption

Question 52

Most smart appliances will look very similar

Answer 52

to the current appliances available.

Question 53

The smart appliance:

Answer 53

• Is an appliance with a computer chip installed that allows the appliance to communicate with a smart meter.

Question 54

The utility benefits from the smart appliances during:

Answer 54

• peak demand by being able to communicate with smart appliances to change their settings.

Question 55

It is estimated that energy consumption by lighting is:

Answer 55

• the second biggest use of energy in the home.

Question 56

By using some form of smart lighting the consumer can reduce energy consumption from lighting by:

Answer 56

• 50% in existing homes and 35% in new construction.

Question 57

One of the biggest changes starts with the consumer:

Answer 57

• Changing from incandescent light bulbs to Light Emitting Diode (LED) lighting or compact florescent lighting (CFL).

Question 58

The average burn time with LED lighting is:

Answer 58

• 35,000 to 50,000 hours compared to

Question 59

The average burn time with an incandescent bulb:

Answer 59

• 750 to 2,500 hours

Question 60

A plug-in hybrid vehicle is:

Answer 60

• a vehicle that runs on battery power until the charge is too low and then switches to a combustion engine for its power source.

Question 61

The Plug-in Hybrid Vehicles can be charged by:

Answer 61

• plugging into a standard 120-volt outlet.

Question 62

Range anxiety:

Answer 62

• A driver’s fear of being stranded by a depleted battery before reaching their destination.

Question 63

An all-electric vehicle is a vehicle that:

Answer 63

• Runs strictly on battery power. When the battery charge is depleted there is no alternative power source.

Question 64

The recharge station will communicate with the smart home to determine the best time to recharge the vehicle’s batteries. Typically, this will be:

Answer 64

• at night when peak demand is low, and the price per kWh is low.