Meters (week 13)
Five amperes on the secondary side
CTs are typically designed to operate at a max of _
Serial number
Check the _ on the seal for comparison to the proper _. To help spot a counterfeit seal, use an unused seal for a side by side comparison
Bar type, donut type, or bushing type
Current transformers for metering are _
Current transformers (CTs)
Devices that step current down for metering purposes
Voltage transformers (VTs also known as potential transformers or PTs)
Devices that step voltage down for metering purposes
Secondary circuits
Donut type CTs are most commonly used on _
Tampering with the meter, bypassing the meter, and by metering errors.
Energy has been diverted by _
A meter or cover and seal to protect the public before leaving the site
If a meters been removed on an energized meter base (socket) install _
Shorting hazards such as a broken meter lug or excessive load can cause an explosive fault. The extent of the electrical flashing that occurs will depend on the size of the service, the distance of the transformer, and the size of the transformer.
If the meter must be removed under load remember that _
Interrupt a large load and start racing between the terminals. There's a method that advises not to remove meter with more than 10 kilowatts of instantaneous load. This applies to electromechanical and electronic meters.
If there's no access to the customer main disconnect switch, and the meter is to be removed, a worker could _
The entire load current, The current carries a representative current that has been stepped down by a current transformer
In a self-contained meter, the current coil carries _ while in a transformer rated meter _
Instrument transformer, wiring trough or customer switch that's ahead of the meter
In addition to sealing a meter, it's also common to seal any _
No moving parts. It can be an electronic meter or a smart meter.
A solid-state meter is a meter with _
Three 120V two wire single phase meters economically packaged into one unit
A three phase meter is actually _
A three wire Delta connected service, four wire Wye (Star) connected service
A three phase service will usually be either _ or a _
AMI
A two way communication technology that allows utilities to remotely collect meter data and customers to review and manage usage in real time
The energy to be measured is supplied at a high voltage, such as transmission, primary, or a high secondary voltage. 240 or 120 volts.
A voltage transformer (VT) is used when _ . A voltage transformer output will supply a voltage at a manageable level to a meter typically rated at _
It doesn't need to carry any load
A voltage transformer is like most transformers except that _
Head end software, the network, network infrastructure, end points
All automated metering systems have four key components which are?
The main switch if possible
Always attempt to drop load with _
PPE, Verifying proper meter and meter base selection, disconnecting load, test the meter socket for faults or backfeed, firmly insert the meter into the socket (bottom first), installation of the meter ring, installation of the meter seal, connect load (if possible) and verify that meter is working properly, record (paper or digitally) The meter information, record (paper or digitally) The meter seal information to associate the meter seal with this meter
Always wear approved _ when installing meters. Proper meter installation consists of:
PPE, read the meter, disconnect the load, remove the seal and meter ring, remove the meter (pull down on the top first), install a socket cover, install the meter ring and the meter seal, complete any necessary paperwork
Always wear approved _ when removing meters. Proper meter removal consists of _
Voltage sensor and current sensor, voltage transformers (VTs) and current transformers(CTs)
And a solid-state meter, and element is made up of a _ that act in A similar fashion to _ for a transformer rated meter
End points
Are the devices installed at the customers location that are used to communicate info to the customer and the utility. Includes meters, home area display units, smart thermostats, smart fridges, smart dryers, etc
Polarity, polarities, instrument transformers, marked with a large dot.
As with all transformers the _ of a VT needs to be known and marked on the transformer. When current enters at the marked primary terminal, the marked secondary terminal is in phase with the primary. The _ of the primary and secondary terminals of _ are often _
Turns ratios proportional to the primary voltage that they're connected to and the output voltage that they supply
As with any transformer VT's have _
Automated meter reading (AMR) Advanced metering infrastructure (AMI)
Automated metering systems consist of two different methods of reading the meter _
Primary and secondary circuits
Bar type CTs are used on both _
Multiplier, actual amount of power consumed, which is critical for accurate billing
Bc the meter is reading a reduced voltage and/or current, a _ must be used to determine the _
Substations circuit breakers and other apparatus. Also on circuit reclosers.
Bushing type CTs are mostly commonly found on _
Single phase or polyphase (three phase)
A service will be either _
A two wire or three wire, 120v service requiring a two wire meter
A single phase service will be either _ A two wire service is a _
Bypassed by tapping in with a parallel service from an overhead or underground service ahead of the meter
A solid state meter and electromechanical meter can be _
Outages, so if the meter is removed it will detect the outage
A solid state meter has the ability to count _
Current to a manageable level that goes through a transformer rated meter
A CT will reduce the _
That the amount of energy consumed by the customer is 10 times the amount shown on the register
A KR or multiplier of 10 would mean _
Solid state meter, Kh constant, the rotating disk, determine the number of watt hours per pulse. This is modified by a scaling factor and is intended to simulate the rotation of a disk by providing a programmed amount of watt hours per scale or series of pulses
A _ also has a _; but in the absence of _, Kh involves the use of a pulse recorder that is used to _
Close examination, small tug
A _ and a _ on the seal will help detect some intentional seal tampering
Voltmeter, Insulation tester. The voltmeter method described here applies to the single phase, 120/240 V meter base
A _ or an _ is more likely to be on a work truck and can be used to check in meter base.
Rotate once for every white hour because it would spin too fast at most services and would cause excessive wear on the meter.
A disk on an electromechanical meter does not _
Meter sealing policy and procedure
A good _ and _ reduce the opportunity for energy diversion
Installing its own facilities, such as transformers, wire, cable, etc
A large industrial customer may get a better rate from the utility company by _
Spin slower, kilowatt hour constant or KH constant
A meter is designed to _ and the number of watt hours per one rotation of the disk referred to as _
A certain range of expected load, of energy used without repeating between meter reading intervals
A meter is rated for _ and the register should show the amount _
10 kilowatts of instantaneous load
A meter with more than _ should not be removed
Measure the energy in a two wire 120 V service
A one element meter is all that is required to _
AMR
A one way communication technology that allows utilities to remotely collect meter data
A meter with two or three single elements that influence a disk (or disks) on a common shaft attached to one register. The consumption measured by each element is, therefore, combine to register the total amount of energy consumed
A polyphase meter requiring a two or three element meter is actually _
Meter that has the capability to have all load current for the service blowing through it at the rated service voltage.
A self-contained meter is a _
Security ring type
In cases where there's a history of tampering or customers restoring their power after having been disconnected, a _ can be installed. These are virtually impossible to remove without damaging the meter socket
Vandal cover
In problem prone locations a _ can improve protection of the meter and reduce risk of tampering
Loss in the amount registered by the meter (possibly 40%) this can result in revenue loss to the utility
Inadvertently leaving a CT short circuited after the meter is installed will cause a _
Wide Area Network (WAN)
Is a network similar to RF Mesh bc it uses a radio frequency but the meters communicate directly to a collector instead of reading from meter to meter. Can use one collector to receive data from 30 to 300 square miles. Can send & receive data from the end points to the collector up to 40 miles away. Collectors placed on towers ranging in height from 50 to 600 ft depending on terrain and how many meters need to be on the collector. One collector has the capability of collecting data from up to 70,000 meters
RF Mesh
Is a network where data travels by radio frequency from one meter to another meter until the info reaches its destination. Uses the meters as receivers and transmitters to send the info to a main router or to the correct meter. More cost effective than Power line carrier but the meters can not be farther than 1,000 ft apart. Used in urban areas. If distance exceeded the utility will have to use a booster to strengthen the signal to reach the meter. Can receive data in as quickly as 30 sec intervals
Power line carrier
Is a network where data travels over existing power lines to send info to the head end software or the meter. By using the power line as the carrier there's not a need for communication from meter to meter. Avg cost per meter to set up a carrier is more expensive than the other network systems bc of the requirement of more network infrastructure. Benefit is it can be used in rural areas where meters are spaced farther apart. Gives utilities in rural areas to use new meter tech and can receive data in as quickly as 2 hour intervals
Head end software
Is the communication software that communicates with the meters to send or receive information. Utilized by both AMR and AMI. Both systems located at a central headquarters where softwares installed to record the data
Network infrastructure
Is the hardware needed for the network to communicate to the head end software and the meter. Hardware consists of routers, collectors, inbound and outbound units, and transformer units. Depending on what network a utility uses will determine what kind of network infrastructure they'll need
Incorrect meter wiring, inadvertently leaving a CT short circuited, instrument transformer wiring, data recording, and an open voltage test point
It's not uncommon for utilities to make errors. _ have all resulted in a customer not paying the proper tariff
Billing systems will highlight any customers who have a major change in their power consumption
Many investigations are initiated bc _
Color coded
Meter connection diagrams are _
AMI or AMR system
Meters that are connected into an _ or _ can highlight a customer who has had a short outage (caused by tampering with the meter) but no trouble call
Visual indicator
Most seals being used are not locks but are a _ of unauthorized entry or tampering.
Meter current coil, the voltage drop in the coil brings the secondary voltage to a safe level.
On a CT when the secondary of the current transformer is connected to the _. What happens?
Driven by gears that are coupled to the meter disk and shaft. The register usually consists of four or five dials with a pointer on each dial
On an electromechanical meter, the register is _
Current coil, potential coil, up one element (or stator) in an electromechanical meter
One _ and one _ working together to turn one disk are the parts that make _
The current coil to induce a magnetic field onto the meter disk causing it to rotate
The voltage coil of a meter element is needed to combine with _
Isolate the voltage and current supply. The meter won't register but will be safe to remove for replacement or testing
Opening the blades of the switch will _
Drilling a small hole through the glass cover and a wire inserted to interfere with the disk rotation, putting a strong magnet near the meter in an attempt to interfere with the operation of the meter, or inserting and connecting a circuit (small wire #12 or #14) into the source side along with the service wires of a cluttered meter base
Other examples of electromechanical meter tampering include _
Instrument transformers
PTs and CTs are also referred to as _
Be read from either direction clock or counterclockwise. The pointer on the right spins the fastest, the pointer on the left the slowest. Each pointer will rotate one digit when the pointer to its right rotates one full revolution
Reading electromechanical meter dials can _
The utility name or logo and a serial number printed on them.
Sealing and locking hardware have _
Single phase, polyphase, electromechanical, solid state, and demand
Self contained meters can be?
600 volts and/or 400 amps. Require transformer rated metering
Self contained meters typically have a limit of _. Therefore any service to a customer that exceeds either of these values may _
Secondary metering, which is 600 V or less and 400 amps or less
Self-contained meters are limited to _
Manually, automatic shorting device
Shorting out the secondary terminals _, anytime the meter is to be removed while energized is necessary when the meter base doesn't have an _
Read remotely from a meter data management center, or if needed, a utility worker can physically go to the meter location and read the digital display. Also have optical port for downloading info
Solid state meters can be _
Bar code that's scanned, scan the meter seal and see if it's the meter seal associated with that meter
Some utilities use seals with a _ when the meters installed. This will associate the meter seal with the meter at that location. If energy diversion is suspected, a utility worker can _
Network
The communication system that carries the data between the meter and the head end software
A wire size big enough to carry the rated load of the meter and consists of a small number of turns.
The current coil of a meter element is made up with _
The CT is wired
The current multiplier depends on how _
Automatic shorting device that'll short out the secondary terminals of the current transformer when the meter is removed
The meter base for a transformer rated meter often has an _
Three wire, 120/240v single phase service which takes a three wire meter
The most common service in the US is _
Power multiplier. Bc customers are billed for power consumed, the power multiplier is used to compensate for the reduced reading at the meter. To determine the actual amount of power consumed, the meter reading is multiplied by the power multiplier
The product of the voltage and current multipliers is the _
Be confused with a three wire single phase service. In other words, these services would both require three wire meters. However the meters would be different
The three wire meter needed for a three phase delta service should not _
Fixed ratio, multiplier of the meter reading, representation of the primary voltage and primary current being measured
The voltage and current are stepped down at a _. The ratio of the VT and CT are multiplied together forming a _ and provide an accurate _
Secondary service being measured or from a potential transformer that steps down the voltage of a transmission or a primary circuit. Although the voltage level is relatively constant compared to the current, the variations and voltage do reflect in the speed of the disk and the amount of energy measured
The voltage measured by the meter can come directly from the _
VTs turns ratio
The voltage multiplier is always equal to the _
Small resistive voltage dividers, small CTs, small representative signals that are proportional to the actual voltage and current to an electronic measuring circuit
The voltage sensors are typically _and the current sensors are _. The sensors provide _
Socket testers
There are _ on the market that can be plugged into a socket meter base to check a meter socket for short circuits, grounds, backfeed, and wiring errors prior to setting the meter
One time use seals, padlock-able sealing rings, reusable electronic seals
There's many kinds of seals or locks from _ , _, _ to _
Transformer rated meters
These meters can be programmed with the applicable ratios and multipliers, which substantially improved the accuracy of the readings. Also allow utility to perform a wide range of power usage analyses much easier than electromechanical meters
Radio Frequency Mesh (RF mesh), Power line carrier (PLC), and Wide Area Network (WAN)
Three type of networks
Either a blinking symbol or a dash that moves across the bottom of the display screen. This represents the disk that's seen on an electromechanical meter
To count the revolutions with a solid state meter there's _
Count the disk rotations
To count the revolutions with an electromechanical meter _
Voltage transformers, current transformers, test switches, transformer rated meters
Transformer rated metering is composed of four main components
The voltage and/or current are too high for self-contained metering
Transformer rated metering is used when _
Secondary services, primary services, and transmission services. Mostly encounter on primary and secondary circuits
Transformer rated meters are used on _
Test switch below the meter to allow for the remove and testing of the meter without opening the secondary circuit from the current transformers
Transformer rated meters typically utilize a _
3.6 x Kh x Revolutions or pulses/ seconds
What's the formula for figuring out the kW
That the type of meter, the meter multiplier, and the meter number match the meter data on record. Also includes a check of the meter seal to ensure that the meter has not been tampered with.
When a meter is to be read, the procedure includes verifying _
First disconnect the customer load
When removing a meter, it's always preferred to _
Hiding or camouflaging where the seal was cut, using a counterfeit seal, or repairing a damaged seal
When the seal is opened, attempts to reseal it includes _
Be kept short circuited
When there's current flowing through the current transformer while the meter isn't installed the secondary must _
Removing the seal and the meter and then opening the voltage test link, putting the meter upside down so it runs backwards, or putting bypass jumpers in parallel with the meter.
With electromechanical meters the most common forms of energy diversion include _
KR constant
_ also known as a meter multiplier or register constant, is a number that represents the ratio between the register gear train and the value registered on the meter dial. The register constant may be 1,10,100, or some integral of 10.
Energy diversion
_ is theft of power that occurs when a consumer manipulates or bypasses the meter installation.
Meter nameplate
_ on a meter will show the range of load for which the meter is designed
Testing, that there is no short circuit, heavy load, or backfeed in the customers wiring before installing any meter
_ should be done at the meter base to ensure _