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T&D Glossary

2011 Transmission & Distribution Glossary

 Term

Definition

# of trees managed

Refers to the estimated number of trees in your entire service area that are in proximity to power lines, and might affect them.

# of trees miles/kilometers managed

Refers to the estimated number of miles/kilometers of overhead lines in your entire service area that might be affected by trees.  This is pole miles, not circuit miles

# of trees removed

Refers to the number removed during the year

# of trees trimmed

Refers to the number trimmed during the year being measured

% of time transformers out of service [automatic]

[(Total hours of automatic transformer outage time)/(number of transformers in service * 8760)] * 100

% of time transformers out of service [non-automatic]

[(Total hours of non-automatic transformer outage time)/(number of transformers in service * 8760)] * 100

Automatic Outage (TADS)

An outage is triggered by an automatic protection device, resulting in a normally in-service element that is not in an in-service state; e.g. there is a partial or full loss of continuous power flow through the element to the system. A successful AC single-pole (phase) reclosing event is not an automatic outage.  See also TADS document – link on our website.

Average % capacity utilized for substation MVA

This includes both power and autotransformers.

Breakers

A circuit breaker is an automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Unlike a fuse, which operates once and then has to be replaced, a circuit breaker can be reset (either manually or automatically) to resume normal operation.

CAIDI

The Customer Average Interruption Duration Index (CAIDI) is a reliability index commonly used by electric power utilities. It is related to SAIDI and SAIFI, and is calculated as

 

CAIDI =      sum of all customer interruption durations         =   SAIDI

                      total number of customer interruptions                 SAIFI

 

CAIDI gives the average outage duration that any given customer would experience once an outage has occurred. CAIDI can also be viewed as the average restoration time

 

CAIDI is measured in units of time, typically minutes or (rarely) hours. It is usually measured over the course of a year.

Captive Muni or Other Transmission Customers

Captive Muni customers is a term we developed years ago when there wasn’t open access for energy sales.  It includes the number of customers that are served by any municipal utilities that you provide all the transmission for.  The point of the question is to understand the number of end-use customers served by your transmission network, even though they may not be your distribution customers. 

Circuit Mile/Kilometer

Physical miles/kilometers of line multiplied by the number of circuits.  For example, two miles of OH line with two circuits on the pole line is equal to four circuit miles.  Include both OH and UG lines.

Circuit Sustained Outage Frequency Mileage Adjusted

Formula: (Total circuit automatic Outages*100)/Total Circuit Miles

Units: # of sustained outages per 100 circuit miles per year

Acronym: SCOF-100Ctmi

Circuit Total Outage Frequency Mileage Adjusted

Formula: (Total circuit automatic Outages*100)/Total Circuit Miles

Units: # of momentary outages per 100 circuit miles per year

Acronym: MCOF-100Ctmi

Circuit Total Outage Frequency,  Mileage Adjusted

Formula: (Total circuit automatic Outages*100)/Total Circuit Miles

Units: # of automatic outages per 100 circuit miles per year

Acronym: TCOF-100Ctmi

Clearance Order

 A request for a line to be out of service

Customer Interruption: Acts of Public (Autos, Dig-ins, Vandalism, etc)

Customer interruptions caused by acts of the public, such as vehicle contact with company distribution facilities, dig-ins, vandalism, etc.

Customer Interruption: Animals

Customer interruptions caused by animal contacts

Customer Interruption: Distribution Equipment Failure

Customer interruptions caused by equipment failures on the distribution system

Customer Interruption: Generation Outages

Customer interruptions caused by outages or shortage of supply on the generation system

Customer Interruption: Lightning

Customer interruptions caused by lightning, other than major events

Customer Interruption: Major Events

Customer interruptions during major events

Customer Interruption: Other

All Others

Customer Interruption: Planned Interruptions

Customer interruptions due to planned (non-emergency) events

Customer Interruption: Substation Outages

Customer interruptions caused by outages originating "inside the substation fence"

Customer Interruption: Transmission Outages

Customer interruptions caused by outages originating on the transmission system

Customer Interruption: Trees

Customer interruptions caused by trees or other vegetation

Customer Interruption: Weather related [ex. lightning]

Customer interruptions caused by inclement weather, other than major events

Customers beyond the meter

This is focused on master-metered buildings, such as apartments, and is designed to count the number of customers who would be counted as individual customers if each unit were separately metered.

Days Away, Restricted, or Transferred (DART) Rate:

This includes cases involving days away from work, restricted work activity, and transfers to another job and is calculated based on (N/EH) x (200,000) where N is the number of cases involving days away and/or job transfer or restriction, EH is the total number of hours worked by all employees during the calendar year, and 200,000 is the base for 100 full-time equivalent employees. An example, drawn from the OSHA website:

 

Employees of an establishment (XYZ Company), including temporary and leased workers, worked 645,089 hours at XYZ company. There were 22 injury and illness cases involving days away and/or restricted work activity and/or job transfer from the OSHA 300 Log (total of column H plus column I). The DART rate would be (22/645,089) x (200,000) = 6.8.

 

Note: The DART rate replaced the Lost Workday Injury and Illness (LWDII) rate. See Figure 2-8 at the end of this Chapter for an optional Incidence Rate Worksheet.

 

The OSHA website can be found at…

 

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=DIRECTIVES&p_id=3205

Design

Design is the final application of the engineering standards or guidelines to fit each unique system need (e.g. a new service, new line, reconductored line, etc.).  Complex designs can be very challenging, with substantial judgment required, and standards simply serving as a starting point, or relatively simple, where application of the relevant standard means there is relatively little judgment or creativity required.

Designer

Someone with a 2-year degree, or perhaps more limited formal education, combined with job-related experience.  Job duties typically involve new services or simple system elements not requiring full engineering training.

Direct labor

This includes:  linemen, crews, electricians, troubleshooters, engineers, designers.

Distributed Storage

Use of devices at various locations to store electricity for use when demand exceeds supply. 

Distribution End-Use Customer

Please provide the count reported on your FERC Form 1.  If you do not report to FERC, use the following definition: an entity (usually defined as a metered point of delivery) who receives electric distribution services.  Do not include customers connected through an LDC.

Distribution O&M Expense

Includes all major maintenance and operation of the distribution system, covering poles, wires, etc.  Some specific items included are trouble calls costs; meter change-outs, installations and other meter shop activities.  Does not include meter reading.  Field service not included:  disconnect/reconnect, etc.  See also:  the definition for FERC Distribution Operations and Maintenance later in this glossary.

Distribution Operations Center

Operating the distribution system; switching orders; scheduling and dispatching trouble crews; VAR/capacitor control, maintenance of operating maps.

Distribution Voltages

For purposes of this survey, we define distribution to be a voltage level below 45kV. The distinction is somewhat arbitrary, but picks a point between 69kv which is generally considered a transmission (or at least sub-transmission) level and 21kV which would generally be considered distribution.

It is unrealistic to ask utilities to redefine their cost or reliability reporting on the basis of these definitions. However, a utility that has very different definitions may want to restate these statistics to better compare their performance.

Element (TADS)

The following are elements for which TADS data are to be collected:

1) AC Circuits>= 200kv (overhead and underground);

2) transformers with >= 200kv low side voltage; 

3) AC/DC Back to back converters with >= 200kv AC voltage on both sides;

4) DC circuits with >= 200kv DC Voltage

Element Availability Percentage

Formula: 1- (total sustained outage hours/total element hours) * 100

Acronym: APC

1QC Variation:  Similar to Circuit Availability (with voltage and element restrictions)  but does not include planned outages

Element Momentary Outage Frequency

Formula: Total Momentary Outages/ Total Elements

Units: # of momentary outages per element per year

Acronym: MOF

1QC Variation:  none

Element Sustained Outage Duration Time

Formula: Total Sustained Outage Hours/Total Elements

Units: # of automatic outage hours per element per year

Acronym: SODT

1QC Variation:  Similar to Average circuit unavailability (aka SAIDI), but has some differences in elements and voltage levels

Element Sustained Outage Frequency

Formula: Total Sustained Outages/ Total Elements

Units: # sustained outages per element per year

Acronym: SOF

1QC Variation:  none

Element Sustained Outage Mean Time to Repair

Formula: Total Sustained Outage Hours/Total Sustained Element Outages

Units: # of automatic outage hours per element outage per year

Acronym: MTTR

1QC Variation:  Similar to average duration of an outage (aka CAIDI), but has some differences in elements and voltage levels

Element Total Automatic Outage Frequency

Formula: Total Automatic Outages/ Total Elements

Units: # of automatic outages per element per year

Acronym: TOF

1QC variation: Similar to outage frequency with the following differences: elements definition is not quite the same as circuit (e.g. a transformer outage is counted as an outage); only applies to elements >=200 kV; excludes outages not triggered by automatic protection devices (e.g. outages initiated by the operations center, usually "planned" outages); includes momentary and sustained outages

Energy Control Center Expense

The O&M expenses associated with operating your transmission control center(s).   This would be a subset of the Transmission O&M expenses.  It’s most likely to be found in your FERC account 561, Load Dispatching, but it might be in other places, so we’re asking that it be broken out.

Engineer

Typically a person with a 4-year degree in Engineering

Engineering

Engineering begins with development and maintenance of standards for use in designing individual jobs.  It also includes determining the final solution to system needs, be it creation of a new line, upgrade of an existing one, or some other related choice. 

Estimating

This is the activity associated with forecasting the costs associated with performance of the full range of engineering/design activity, along with the construction activity, to complete a given project. 

Estimator

Most often someone with job-related experience, without necessarily any formal education beyond high school. 

Extraordinary Items

Exclude unusual costs such as related to extreme weather events (Ike, Katrina), etc.

 

They will be events and transactions of significant effect which are abnormal and significantly different from the ordinary and typical activities of the company, and which would not reasonably be expected to recur in the forseeable future.  To be considered as extraordinary under the above guidelines, an item should be more than approximately 5 percent of income, computed before extraordinary items.

Facilities

A building where company trucks are parked and field crews get their assignments and start their day.  This may include substations if you use them for that purpose

Facility Point

Units maintained such as Pole and the equipment attached to it.

FERC Distribution Lines and Substation Maintenance Expense

(590) Maintenance Supervision and Engineering

(591) Maintenance of Structures

(592) Maintenance of Station Equipment

(593) Maintenance of Overhead Lines

(594) Maintenance of Underground Lines

(595) Maintenance of Line Transformers

(596) Maintenance of Street Lighting and Signal Systems

(597) Maintenance of Meters

(598) Maintenance of Miscellaneous Distribution Plant

The above list is directly from a FERC form and shows what is normally included in FERC.  For our study, we then back out some of these items as noted in the questionnaire

FERC Distribution Lines and Substation Operation Expense

(580) Operation Supervision and Engineering

(581) Load Dispatching

(582) Station Expenses

(583) Overhead Line Expenses

(584) Underground Line Expenses

(585) Street Lighting and Signal System Expenses

(586) Meter Expenses

(587) Customer Installations Expenses

(588) Miscellaneous Expenses

(589) Rents

The above list is directly from a FERC form and shows what is normally included in FERC.  For our study, we then back out some of these items as noted in the questionnaire.  Meter Reading is not included in Distribution Operation expense.

FERC Distribution Plant in Service and Plant Additions

These items are included in Distribution (and Distribution Substation) plant in service or plant additions.

(360) Land and Land Rights

(361) Structures and Improvements

(362) Station Equipment

(363) Storage Battery Equipment

(364) Poles, Towers, and Fixtures

(365) Overhead Conductors and Devices

(366) Underground Conduit

(367) Underground Conductors and Devices

(368) Line Transformers

(369) Services

(370) Meters

(371) Installations on Customer Premises

(372) Leased Property on Customer Premises

(373) Street Lighting and Signal Systems

(374) Asset Retirement Costs for Distribution Plant

FERC Transmission Lines and Substation Maintenance Expense

(568) Maintenance Supervision and Engineering

(569) Maintenance of Structures

(569.1) Maintenance of Computer Hardware

(569.2) Maintenance of Computer Software

(569.3) Maintenance of Communication Equipment

(569.4) Maintenance of Miscellaneous Regional Transmission Plant

(570) Maintenance of Station Equipment

(571) Maintenance of Overhead Lines

(572) Maintenance of Underground Lines

(573) Maintenance of Miscellaneous Transmission Plant

The above list is directly from a FERC form and shows what is normally included in FERC.  For our study, we then back out some of these items as noted in the questionnaire.

FERC Transmission Lines and Substation Operation Expense

(560) Operation Supervision and Engineering

(561) Load Dispatching

(561.1) Load Dispatch-Reliability

(561.2) Load Dispatch-Monitor and Operate Transmission System

(561.3) Load Dispatch-Transmission Service and Scheduling

(561.4) Scheduling, System Control and Dispatch Services

(561.5) Reliability, Planning and Standards Development

(561.6) Transmission Service Studies

(561.7) Generation Interconnection Studies

(561.8) Reliability, Planning and Standards Development Services

(562) Station Expenses

(563) Overhead Lines Expenses

(564) Underground Lines Expenses

(565) Transmission of Electricity by Others

(566) Miscellaneous Transmission Expenses

(567) Rents

The above list is directly from a FERC form and shows what is normally included in FERC.  For our study, we then back out some of these items as noted in the questionnaire.

FERC Transmission Plant in Service and Plant Additions

These items are included in Transmission (and Transmission Substation) plant in service or plant additions.

(350) Land and Land Rights

(352) Structures and Improvements

(353) Station Equipment

(354) Towers and Fixtures

(355) Poles and Fixtures

(356) Overhead Conductors and Devices

(357) Underground Conduit

(358) Underground Conductors and Devices

(359) Roads and Trails

(359.1) Asset Retirement Costs for Transmission Plant

Field: Groundmen

Supports crew in non-electrician role; includes classifications such as groundman, helper, and equipment operator.

Field: Substation Crew Members

Skilled electrician who performs operations, construction and maintenance work in substations; may perform at several skill levels (apprentice, journeyman, lead, working foreman. Also includes crew members in non-electrician roles such as groundman, helper

Field: Substation Operators

Electricians assigned primarily to operate substations in the field; may be assigned to a substation or an assigned territory.

Field: Transmission Linemen

Skilled electrician who performs operations, construction and maintenance work on the transmission system; may perform at several skill levels (apprentice, journeyman, lead, working foreman); may work on overhead and underground work; allocate transmission

Field: Troubleshooters

Lineman assigned full time to perform switching (line devices and usually substation breakers) and to respond to outages on the electrical system (line fuses, line down, customer lights out, part lights out); may also perform meter sets, inspection, maintenance

Full-time Equivalent employees

Employees assigned full time to a function. Include full-time supervisors and managers.  Or full-time employees who spend part time in different functions. Include part time supervisors and managers.

Also include employees who spend less than 40 hours per week. 

When calculating FTE value use 2080 as the denominator.

50% rule:  Include a person in an activity if they spend at least 50% of their time on that activity; you can indicate they are 0.5 FTEs.  If a person divides their time so that they don’t spend at least 50% of their time on an activity they probably should be in the “Support” Group.

Direct Labor rule:  a person having direct interactions with a part of the system is considered direct labor.  Everyone else is either supervision or support.  Use the 50% rule if they divide their time.

Outsourcing:  If you outsource a function entirely do not attempt to turn that into FTEs.

IEEE Standard 1366

IEEE Standard 1366 has become the major guide for definitions on distribution reliability. Though not every utility follows exactly, some of the key issues identified by this standard include:

·       Outage duration to be considered an interruption

·       Definition of a major event (2.5 Beta Method)

Initiative

A new activity, program, or process where success or failure is being tracked but it is too soon to tell the outcome.

Intelligent Grid

An intelligent grid uses two-way communication.  Data flows in to the utility operation center from all points over the grid, including transformers, SCADA equipment, meters, street lights, traffic/security cameras, and energy management units in the home or business. The utility can also send outgoing data streams to operate switches and other devices, deliver real-time pricing information to customer premises, connect/disconnect meters, or activate load control units.

Interconnections

The number of transmission voltage interconnections with generating plants and electric utilities.   Also the transmission interconnections with retail customers.  Include all transmission voltage connections to any other system not owned by your company.

Job Classifications

Within the individual job classifications, the ways in which different companies split the responsibilities for planning, engineering, and design vary significantly.  For example, one company may have degreed engineers do almost all the engineering and design functions, as well as the cost estimating, while another company might have degreed engineers do only the preliminary engineering, have the designs completed by Designers/Technicians, and have the cost estimates done by an Estimator.  One of the goals of this section of the questionnaire is to learn how each company splits the functions, and how the activities are split among the different job classifications.

Level 2 Transmission Load Relief

We use this as an indication of congestion. As defined in  Power System Operations and Electricity Markets - Google Books Results:  "The purpose of NERC TLR (Transmission Load Relief) procedure to define the actions and communications to reduce the flow on . . .a transmission element of the bulk power transmission system. . . The effect of a TLR level 2 [Hold] is to cause all schedules to hold at the current active flow levels.

Looped Circuit

The final connection to the customer is from a two-ended circuit with an open switch at or near the center, so that service may be restored manually by operating switches in case of a failure of any section of the circuit.

Lost Time Incident Rate  (illness and injury)

Rate for Total Lost Time Incidents  (illness and injury) calculated:

N = Sum of the number of recordable [nonfatal] injuries and illnesses resulting in days away from work in a given time frame.

EH = Total number of hours worked by all employees in a given time frame (either 1 year for an annual rate or 3 years for a 3-year combined rate).

200,000 = Equivalent of 100 full-time workers working 40-hour weeks 50 weeks per year.

N / EH *200,000

Rate for Total Lost time Incidents calculated:

(Total of OSHA 300A Column H) x 200,000) / Total Hours Worked

Lost Time Severity Rate (illness and injury)

Lost Time Severity Rate (illness and injury): (# of lost or restricted days X 200,000) / Total Hours Worked, where “# of Lost Days” can be obtained from OSHA 300/300A Column K.

Mean time between Sustained Element Outages (mean "Up Time")

Formula: (Total Element Hours - Total Sustained)/Total Elements

Units: Average # of hours of operation of an element before it fails

Acronym: MTBF

Median time to repair Sustained Element Outage Failures

The time when 50% of the Mean Time to Repair minutes are greater than this figure

Units: Median # of hours of operation of an element before it fails

Acronym: MdTTR

Multi-Circuit Sustained Outage Frequency Mileage Adjusted

Formula: (Total circuit automatic Outages*100)/Total Circuit Miles

Units: # of sustained outages per 100 circuit miles per year

Acronym: SMCOF-100Ctmi

Multi-Circuit Total Outage Frequency Mileage Adjusted

Formula: (Total circuit automatic Outages*100)/Total Circuit Miles

Units: # of momentary outages per 100 circuit miles per year

Acronym: MMCOF-100Ctmi

Multi-Circuit Total Outage Frequency,  Mileage Adjusted

Formula: (Total circuit automatic Outages*100)/Total Circuit Miles

Units: # of automatic outages per 100 circuit miles per year

Acronym: TMCOF-100Ctmi

MVA of Transmission substation capacity

This is for both autotransformers and for power transformers with transmission voltage on the low side.  Use what you report in the FERC Form 1.

MW-Miles

For each circuit, multiply the number of miles by total peak load capacity defined in megawatts; the sum of all circuits for a voltage class is the total mw-miles for voltage class.  Use the transfer capacity of lines as defined in your base-case load flow for peak conditions.

Network Circuit

Secondary network typical of downtown  urban areas where multiple primary sources are parallel-connected on the secondary side and protected by automated switches (“network protectors”).

New Business Capital Additions

Capital additions primarily to hook up a specific new customer at the distribution or transmission level to generate additional revenues. Does not include expenditures to replace in kind, to improve reliability, or to meet general increase in system load. Include new interconnections.

New Customers Added to system

Includes new meter set or major panel upgrade, and we're looking for gross, not net.

Number of new interconnections

The number of new interconnections that were built during the year.  We’re focused here on the interconnections to the transmission system at transmission voltage level.

OH structure miles/kilometers trimmed

Refers to the number of OH structure miles/kilometers actually trimmed during the year being measured.

Outage cause: Contamination

Automatic Outages caused by contamination such as bird droppings, dust, corrosion, salt spray, industrial pollution, smog or ash.

Outage cause: Environmental

Automatic Outages caused by environmental conditions such as earth movement (including earthquake, subsidence, earth slide), flood, geomagnetic storm, or avalanche.

Outage cause: Failed AC Circuit Equipment

Automatic Outages related to the failure of AC Circuit equipment, i.e., overhead or underground equipment "outside the substation fence."

Outage cause: Failed AC Substation Equipment

Automatic Outages caused by the failure of AC Substation; i.e., equipment “inside the substation fence” including Transformers and circuit breakers but excluding Protection System equipment.

Outage cause: Failed AC/DC Terminal Equipment

Automatic Outages caused by the failure of AC/DC Terminal equipment, i.e., equipment "inside the terminal fence" including PLC (power-line carrier) filters, AC filters, reactors and capacitors, Transformers, DC valves, smoothing reactors, and DC filters but excluding Protection System equipment

Outage cause: Failed DC Circuit Equipment

Automatic Outages related to the failure of DC Circuit equipment "outside the terminal fence."  However, include the failure of a connecting DC bus within an AC/DC Back to-Back Converter in this category.

Outage cause: Failed Protection System Equipment

Automatic Outages caused by the failure of Protection System equipment.  Includes any relay and/or control misoperations except those that are caused by incorrect relay or control settings that do not coordinate with other protective devices.  Categorize these as "Human Error".

Outage cause: Fire

Automatic Outages caused by fire or smoke.

Outage cause: Foreign Interference

Automatic Outages caused by foreign interference from such objects such as an aircraft, machinery, a vehicle, a train, a boat, a balloon, a kite, a bird (including streamers), an animal, flying debris not caused by wind, and falling conductors from one line into another. Foreign Interference is not due to an error by a utility employee or contractor.  Categorize these as “Human Error.”

Outage cause: Human Error

Automatic Outages caused by an incorrect action traceable to employees and/or contractors for companies operating, maintaining, and/or providing assistance to the Transmission Owner will be identified and reported in this category.  Also, any human failure or interpretation of standard industry practices and guidelines that cause an outage will be reported in this category.

Outage cause: Lightning

Automatic Outages caused by lightning.

Outage cause: Other

Automatic Outages for which the cause is known; however, the cause is not included in the above list.

Outage cause: Power system Condition

Automatic Outages caused by power system conditions such as instability, overload trip, out-of-step, abnormal voltage, abnormal frequency, or unique system configurations (e.g. an abnormal terminal configuration due to existing condition with one breaker already out of service).

Outage cause: Unavailable

Use for Sustained Outages for which either the Initiating or Sustained Cause Codes are unavailable to the Transmission Owner.  If a Transmission Owner uses this code for Sustained Outages, it should be used on only one type of Cause Code (initiating or Sustained), whichever is unavailable.

Outage cause: Unknown

Automatic Outages caused by unknown causes should be reported in this category.

Outage cause: Vandalism, Terrorism or Malicious Acts

Automatic Outages caused by intentional activity such as shot conductors or insulators, removing bolts from structures, and bombs.

Outage cause: Vegetation

Automatic Outages caused by vegetation with the following exclusions: (1)  Vegetation-related outages that result from vegetation falling into lines from outside the right of way that result from natural disasters shall not be considered reportable with the Vegetation Cause Code.  Examples of disasters that could create non-reportable Vegetation Cause Code outages include, but are not limited to, earthquakes, fires, tornados, hurricanes, landslides, wind shear, major storms as defined either by the Transmission Owner or an applicable regulatory body, ice storms, and floods, and  (2) Vegetation-related outages due to human or animal activity shall not be considered reportable under the Vegetation Cause Code.  Examples of human or animal activity that could cause a non-reportable Vegetation Cause Code outage include, but are not limited to, logging, animal severing tree, vehicle contact with tree, arboricultural activities or horticultural or agricultural activities, or removal or digging of vegetation.  Outages that fall under the exclusions should be reported under another Cause Code and not the Vegetation Cause Code.

Outage cause: Weather, excl lightning

Automatic Outages caused by weather such as snow, extreme temperature, rain, hail, fog, sleet/ice, wind (including galloping conductor), tornado, microburst, dust storm, and flying debris caused by wind.

Peak % capacity utilized for substation MVA

This includes both power and autotransformers.

Percentage of Element  Automatic Outages associated with Disturbance Report (either OE-417 or EOP-004)

Formula: Total Automatic Outages Elements associated with a disturbance report/Total Automatic outages

Acronym: PCDR

Percentage of Elements with Zero Automatic Outages

Formula: Total elements with Zero Automatic Outages/Total Elements

Acronym: PCZO

Planner

Most often a person with a 4-year Engineering degree. 

Planning

The act of determining the upcoming needs for capital projects.  It includes identifying where new and/or reconfigured lines and stations will be needed, and arranging for or performing the initial engineering work to determine the best overall solution for the need.  It is typically based on forecasts of the electric system load, combined with understanding the system design and philosophy.

Practice

An activity, program, or process that has been in place for a while where it is possible to measure the outcome (success or failure)

Radial Circuit

Primary comes from a single source, terminating without any tie to another source.  Even though the main-line primary may have ties to other main-lines, the end of the circuit at the customer has no tie.

Recordable Incident Rate (illness and injury)

Rate for Total Recordable Incidences (illness and injury) calculated:

N = Sum of the number of recordable nonfatal injuries plus illnesses in a given time frame (either 1 year for an annual rate or 3 years for 3-year combined rate).

EH = Total number of hours worked by all employees in a given time frame (either 1 year for an annual rate or 3 years for a 3-year combined rate).

200,000 = Equivalent of 100 full-time workers working 40-hour weeks 50 weeks per year.

(N *200,000) / EH

(Total of OSHA 300A Columns G + H + I + J) x 200,000) / Total Hours Worked

Regulatory/ISO Expense

This is an area of expense that is a subset of O&M expenses for Transmission.  It might show up in a variety of different Transmission O&M accounts.  What we’re trying to find is the charges paid to an ISO for their services to the utility.  For some utilities this will be essentially zero.  For others, it can be pretty substantial.

Right of Way Mile

Right of Way mile is a mile of right of way, regardless of width of the right of way.  Structure mile is a mile of structures supporting one or more circuits.  A mile of right of way containing two sets of structures would be two structure miles, but one right of way mile.  It is also possible to have structure miles on public streets or in roadway medians, etc, that are not on any right of way.

Rural

Fewer than 50 customers per square mile

Safety Rates

Include office and field.  Exclude meter readers and customer service related employees.  Exclude employees performing credit-related disconnects/reconnects, high bill investigations, turn-ons/turn-offs.

SAIDI

The System Average Interruption Duration Index is commonly used as a reliability indicator by electric power utilities. SAIDI is the average outage duration for each customer served, and is calculated as:

SAIDI =      sum of all customer interruption durations

                      total number of customers served

SAIDI is measured in units of time, often minutes or hours. It is usually measured over the course of a year.

SAIFI

The System Average Interruption Frequency Index is commonly used as a reliability indicator by electric power utilities. SAIFI is the average outage frequency for each customer served, and is calculated as:

SAIFI =      sum of all customer interruptions

                  total number of customers served

SAIFI is measured in units of interruptions per customer. It is usually measured over the course of a year.

SCADA

SCADA is the acronym for Supervisory Control And Data Acquisition.  SCADA systems are typically used to perform data collection and control at the substation level. Some systems are called SCADA despite only performing data acquisition and not control.

Secondary voltages

<1kV

Spending: AMI Investment

Investment in automated metering infrastructure with two-way communication and control capability

Spending: Capacity Additions

Expenses to serve "load growth".  "Load growth" is not specifically attributable to any one source.  This is usually due to general area growth, and mainly larger capacity additions, like new substations or feeders.

Spending: Equipment Maintenance

 

Spending: Equipment Replacement

Refers to replacement line equipment such as  wires, poles, transformers, conduit, switchgears, cross-arms, capacitors, relays, meters (meter devices), etc.

Spending: Expand

Spending to increase capacity: additional transformers at existing substations; replacing substations with new ones with higher capacity; additional lines on existing poles, etc.  This is typically in response to increased demand from existing customers.

Spending: Mandatory Relocation

Relocation of facilities required by government or franchise agreements.  These may or may not be reimbursed.

Spending: New Interconnections

New connection to another electric system, intended for the transfer of power between two systems

Spending: O&M Associated with Capital

O&M spending in conjunction with capital projects.  An example might be tree-trimming done in preparation for an installation of some capital equipment.

Spending: Other Line Inspection/Patrolling

Costs of inspections of electric lines for assessment of maintenance and replacement needs.  Does not include pole testing and treatment, which is a different category.

Spending: Pole Replacements

Replacement of poles, mainly due to pole maintenance programs, but could include pole failures.

Spending: Reliability Improvement

Expenditures specifically intended for reliability improvement

Spending: Restore Service

Restoration of service during normal weather or during major storms

Spending: Serve New

Spending money for brand new sites: new substations; new pole lines; etc.  Building to serve brand new subdivisions; new industrial areas, major load additions for industrial or commercial customers, etc.  Interconnections with new generation sites.  New generation is not included since we’re studying Transmission and Distribution only.  This is typically in response to new demand from new customers.

Spending: Sustain

Basically maintenance; repairs; keeping the system that exists up-to-date; improving the existing system and adding new technologies.  Replacements equipment including due to system damage from major events. Spending on SCADA is part of sustain as it is about improving the existing system, but not about increasing capacity

Spending: Wood Pole Inspection/ Maintenance

This is the inspection, boring/testing of wood poles, along with pole treatment and reinforcement.

Stores Loading Rate: 

a percentage added to the actual cost of a stores item to account for the storeroom cost (storekeeper salaries, storeroom expenses, internal transportation, etc),  See the definition of FERC Acct 163.

Structure Mile/Kilometer

Physical miles of line irrespective of the number of circuits. For purposes of this survey structure miles refers to both overhead pole miles and underground trench miles.

 

Difference between ROW mile and Structure Mile:
Right of Way mile is a mile of right of way, regardless of width of the right of way.  Structure mile is a mile of structures supporting one or more circuits.  A mile of right of way containing two sets of structures would be two structure miles, but one right of way mile.  It is also possible to have structure miles on public streets or in roadway medians, etc, that are not on any right of way.

Substations

In the U.S., FERC provides a series of guidelines based on function. When two functions exist on the site, they offer the option of splitting a substation between transmission and distribution or predominant use. We would encourage members to split the function and report as both a T and D substation.

We’re looking for transmission stations that are classified as “transmission” whether it's an auto-transformer or a power transformer.  If you have a station that has both transmission and distribution, we’re looking for a “predominant use” judgment.  

1.        Our standard definition is that substations are categorized as transmission based upon their LOW SIDE voltage. A substation that contains transformers that convert 69kv to 12kv would be distribution.

2.        We want to include both autotransformers and power transformers in the count.

3.        We recognize rated capacity can depend upon operating conditions. We will rely on each utility to provide a reasonable rated capacity based on their normal conditions.

4.        Some Canadian utilities have transmission substations that contain "distribution" transformers (115kv to 12kv).  The Canadians typically classify these as transmission based on high side voltage. In the past we actually let people self-define, since the FERC rules are based on function. Here we probably would invoke a "predominant use" rule and let them call these transmission stations and call these transformers transmission.

5.        Another issue frequently brought up is "Tanks" vs. "Banks". We want to count three phase banks.

6.        Another issue raised is whether to include AC/DC converter stations. For benchmarking purposes, we say yes, even though it is an imperfect answer.

7.       We recognize the existence of AC/DC converter stations, but would prefer to exclude them from the study.

8.      Small, pole-mounted mini-substations (e.g. transformers, protective devices and a switch) should not be counted as substations.

Support: Mapping & Records

Technicians who create and maintain design drawings, maps, and records of the distribution system (a.k.a. mappers, drafting technicians, CADD Operators, Records Clerks).

Support: Relay Technicians

Technicians who specialize in installing and testing transmission and distribution voltage relays that primarily are installed in substations.

Support: SCADA Technicians

Technicians who support operation of the SCADA system that usually have primary terminals in substations and control rooms.

Sustained Outage (TADS)

An automatic outage with an outage duration of 1 minute or greater

Technician

Often a person with a 2-year degree, or one with more limited formal education, but with job-related experience

Transformer failures

A failure is any loss of function that would require the unit to be taken out of service. A diagnostic test that resulted in a planned outage would not necessarily be considered a failure. Examples:  fan, tap changer, coil, bushing.

Transformer failures

For transmission transformers, this is regardless of whether they are autotransformers or power transformers.

Transformers

A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled electrical conductors. A changing current in the first circuit (the primary) creates a changing magnetic field; in turn, this magnetic field induces a changing voltage in the second circuit (the secondary). By adding a load to the secondary circuit, one can make current flow in the transformer, thus transferring energy from one circuit to the other.  For counting purposes, report "banks", not "tanks".

Transmission circuits

Our study defines transmission as 46kv or above. We include AC and DC circuits.

Transmission Line Availability

1 - (Total Number of Hours Transmission Circuits Were NOT in Service / 8760). Note that a line out for an extended period of time can be excluded from calculation.

Transmission Line Availability

Transmission Line Availability   1 - (Total Number of Hours Transmission Circuits Were NOT in Service / 8760). Note that a line out for an extended period of time can be excluded from calculation.  An outage measured in weeks could be excluded from the data. An outage of this generation would suggest that there was an alternate feed or some other alternative supply.

Transmission Substation

Transmission station is one with the low-side voltage at transmission level.  We’re looking for transmission stations that are classified as “transmission” whether its an auto-transformer or a power transformer. If you have a station that has both transmission and distribution, we’re looking for a “predominant use” judgment.  If the station is “predominately distribution”, with only a small amount of transmission equipment, then we aren’t looking for that.

Tree

Use your own definition, but the forestry definition for a tree is a minimum of 4" diameter.

TSAIDI (circuit)

The average number of minutes a circuit is out each year.

 

TSAIDI (POD)

The average number of minutes a Point of Delivery is out each year. NOTE: calculation of PODs is not consistent among utilities because of different system configurations, but is intended to be the switch point.

 

Urban

>250 customers per square mile

 

Utilization Factor

Ratio of the maximum demand load to the normal rated capacity of the system for the reporting year. Maximum demand load is defined as the maximum observed load for a particular time interval. (Use your Utility's normal time interval standard for determination). NOTE: this is non-coincident peak demand for each circuit.

 

Vehicle Incident Rate (preventable and non-) (aka Motor Vehicle Accident Rate)

Most utilities report all reportable accidents, whether preventable or not and regardless of fault. In general, we want utilities to include personal vehicles when used on company business.

 

Voltage Classes

The following voltage classes will be used for reporting purposes:

Distribution classes

5kV class = >1kV, <=9kV

15kV class = >9kV, <=15kV

25kV class = >15kV to <=26kV

35kV class = >26kV to <=36kV

44kV class = >36kV to <=44kV

Transmission classes

<69kV

69kV class (>=69kV <100kV)

100kV class (>=100kV <200kV)

200kV Class (>=200kV <300kV)

300kV Class (>=300 kV <400 kV

400kV and above

For transformers, the voltage class reported will be the high-side voltage, even though the cut-off voltage used in the definition is referenced on the low-side

 

Voltage levels

These are the standard “medium voltages” from ANSI C84.1:

 

4160/2400          5kV

8320/4800          5kV

12000/6930       15kV

12470/7200       15kV

13200/7620       15kV

13800/7970       15kV

20780/12000    25kV

22860/13200    25kV

24940/14400    25kV

34500/19920    35kV

 

Notice that there’s nothing above 35kV.  We do include higher voltages, as shown above.

 

 

 

     

 

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