Grid & Distribution / Power Industry Terms

Comprehensive vocabulary flashcards covering power industry, grid, and distribution terms, voltage classifications, operational alerts, loss definitions, and regulatory planning concepts.

Fast Start

The capability of a Generating Unit or Generating Plant to start and synchronize with the Grid within $15\,\text{minutes}$.

Backup Reserve

A Fast Start generating unit that can synchronize with the Grid and provide its declared capacity for a minimum period of $8\,\text{hours}$; also called Cold Standby Reserve.

Spinning Reserve

The component of Contingency Reserve synchronized to the Grid and ready to take on Load; also called Hot Standby Reserve.

Contingency Reserve

Generating capacity intended to take care of the loss of the largest Synchronized Generating Unit or power import from a single Grid interconnection, whichever is larger; includes Spinning Reserve and Backup Reserve.

Primary Response

The automatic response of a Generating Unit to frequency changes released increasingly from $0\text{ to }5\,\text{s}$ from the time of frequency change, fully available for the next $25\,\text{s}$.

Secondary Response

The automatic response to frequency fully available $25\,\text{s}$ from the time of frequency change to take over from Primary Response, sustainable for at least $30\,\text{min}$.

Blue Alert

A notice issued by the System Operator when a tropical disturbance is expected to make landfall within $24\,\text{hours}$.

Demand Control Imminent Warning

A warning from the System Operator issued when a Demand reduction is expected within the next $30\,\text{minutes}$.

Planned Activity Notice

A notice issued by a User to the Grid Owner and System Operator for any planned activity or shutdown at least $7\,\text{days}$ prior to the actual activity.

Schedule Day

The period from $0000\text{H}$ to $2400\text{H}$ each day.

Critical Loading

The condition when the loading of transmission lines or substation equipment is between $90\%$ and $100\%$ of the continuous rating.

Imminent Overloading

The condition when the loading of transmission lines or substation equipment is above $100\%$ up to $110\%$ of the continuous rating.

Emergency State

The Grid operating condition when a Multiple Outage Contingency has occurred without resulting in Total System Blackout and a generating deficiency exists, voltages are outside $0.90$ to $1.10$, or equipment loading is above $110\%$ of continuous rating.

Low Voltage (LV)

A voltage level not exceeding $1000\,\text{V}$ ($1\,\text{kV}$).

Medium Voltage (MV)

A voltage level exceeding $1\,\text{kV}$ up to $34.5\,\text{kV}$.

High Voltage (HV)

A voltage level exceeding $34.5\,\text{kV}$ up to $230\,\text{kV}$.

Extra High Voltage (EHV)

A voltage level exceeding $230\,\text{kV}$ up to $765\,\text{kV}$.

Overvoltage

A Long Duration Voltage Variation where the RMS value of the voltage is greater than or equal to $110\%$ of the nominal voltage.

Undervoltage

A Long Duration Voltage Variation where the RMS value of the voltage is less than or equal to $90\%$ of the nominal voltage.

Short Duration Voltage Variation

A variation of the RMS value of the voltage from its nominal value for a time greater than one-half cycle of the power frequency but not exceeding $1\,\text{minute}$.

Long Duration Voltage Variation

A variation of the RMS value of the voltage from nominal voltage for a time greater than $1\,\text{minute}$.

Voltage Sag

A Short Duration Voltage Variation where the RMS value of the voltage decreases to between $10\%$ and $90\%$ of nominal voltage; also known as Voltage Dip.

Voltage Swell

A Short Duration Voltage Variation where the RMS value of the voltage increases to between $110\%$ and $180\%$ of nominal voltage.

Voltage Fluctuation

Systematic or random RMS voltage envelope changes where the RMS value of the voltage is between $90\%$ and $110\%$ of the nominal value.

Large Generator

A Generation Company whose generating facility at the Connection Point has an aggregate capacity in excess of $20\,\text{MW}$.

Small Generator

A Generation Company whose generating facility at the Connection Point has an aggregate capacity of $20\,\text{MW}$ or below.

Large Customer

A customer with a demand of at least $1\,\text{MW}$, or the threshold value specified by the ERC.

System Loss

The total Energy injected into the Grid or Distribution System minus the total Energy delivered to Distributors and End-Users.

Technical Loss

The component of System Loss inherent in the physical delivery of electric energy, including conductor loss, transformer core loss, and technical errors in meters.

Non-Technical Loss

The component of System Loss not related to physical electrical characteristics, caused primarily by human error, meter tampering, and erroneous meter reading.

Administrative Loss

The component of System Loss referring to energy used in proper Grid operation (e.g., station service) that is not classified as Technical or Non-Technical Loss.

Total Harmonic Distortion (THD)

The ratio of the root-mean-square value of harmonic content to the root-mean-square value of the fundamental quantity, expressed in percent.

Total Demand Distortion (TDD)

The ratio of the root-mean-square value of harmonic content to the root-mean-square value of the rated or maximum demand fundamental quantity, expressed in percent.

Momentary Average Interruption Frequency Index (MAIFI)

The total number of momentary customer power interruptions within a given period divided by the total number of customers served within the same period.

Negative Sequence Unbalance Factor (NSUF)

The ratio of the magnitude of the negative sequence component of voltages to the magnitude of the positive sequence component, expressed in percent.

Zero-Sequence Unbalance Factor (ZSUF)

The ratio of the magnitude of the zero sequence component of voltages to the magnitude of the positive sequence component, expressed in percent.

Total System Blackout

The condition when all generation in the Grid has ceased, the entire System has Shutdown, and the System Operator must implement a Black Start.

Partial System Blackout

The condition when a part of the Grid is isolated from the rest of the Grid and all generation in that part has Shutdown.

Black Start

The process of recovery from Total System Blackout using a Generating Unit with the capability to start and synchronize without an external power supply.

Isolation

The electrical separation of a part or Component from the rest of the electrical system to ensure safety when maintaining or when service is not required.

Grounding

A conducting connection by which an electrical circuit or Equipment is connected to earth or to a conducting body of relatively large extent.

Outage

The state of a Component when it is not available to perform its intended function due to some event directly associated with that Component.

Interruption

The loss of service to a Customer or group of Customers or other facilities resulting from one or more Component Outages.

Merit Order Table

The list showing offer prices and corresponding capacity of Scheduled Generating Units arranged such that the lowest offer price is at the top of the list.

Captive Market

Refers to electricity End-users who do not have the choice of a Supplier of electricity, as determined by the ERC.

Contestable Market

Refers to electricity End-users who have a choice of a Supplier of electricity, as determined by the ERC.

Open Access

Refers to the system of allowing any qualified Person the use of transmission and/or distribution systems and associated facilities subject to approved wheeling rates.

Grid Code

The set of rules, requirements, procedures, and standards governing the safe, reliable, secured, and efficient operation, maintenance, and development of the high-voltage backbone Transmission System.

Distribution Code

A compilation of rules and regulations governing electric utilities in the operation, maintenance, and development of their Distribution System.

Reliability

The probability that a System or Component will perform a required task for a specified time; the ability of a power System to continuously provide service to its Customers.

Security

The continuous operation of a power system in the Normal State, ensuring safe and adequate supply of power to End-Users, even when some parts or Components are on Outage.

Stability

The ability of the dynamic Components of the power System to return to a normal or stable operating point after being subjected to some form of change or disturbance.

Yellow Alert

A notice issued by the System Operator when Contingency Reserve is less than the capacity of the largest Synchronized Generating Unit or power import from a single interconnection, whichever is higher.

Red Alert

An alert issued by the System Operator when Grid Contingency Reserve is zero, a generation deficiency exists, or there is Critical Loading or Imminent Overloading.

Security Red Alert

A notice issued by the System Operator when peace and order problems exist which may affect Grid operations.

Power Development Program (PDP)

The indicative plan for managing Demand through energy-efficiency programs and upgrading, expanding, rehabilitating, repairing, and maintaining power generation and transmission facilities, formulated yearly by the DOE.

Philippine Energy Plan (PEP)

The overall energy program formulated and updated yearly by the DOE and submitted to Congress pursuant to R.A. 7638.

Transmission Development Plan (TDP)

The program for expansion, reinforcement, and rehabilitation of the Transmission System prepared by the Grid Owner and submitted to the DOE for integration with PDP and PEP.

Wholesale Electricity Spot Market (WESM)

The electricity market established by the DOE pursuant to Section 30 of the Act.

Grid Owner

The party that owns the high voltage backbone Transmission System and is responsible for maintaining adequate Grid capacity in accordance with the Grid Code.

System Operator

The party responsible for generation Dispatch, the provision of Ancillary Services, and operation and control to ensure safety, Power Quality, Stability, Reliability, and Security of the Grid.

Market Operator

An independent group whose task includes the operation and administration of the Wholesale Electricity Spot Market in accordance with the Market Rules.

Supplier

Any person or entity authorized by the ERC to sell, broker, market, or aggregate electricity to the End-users.

Distribution Utility

Any EC, private corporation, government owned utility or existing local government unit which has an exclusive franchise to operate a Distribution System in accordance with its franchise and the Act.

Fast Start

The capability of a Generating Unit or Generating Plant to start and synchronize with the Grid within $15\,\text{minutes}$.

Backup Reserve

A Fast Start generating unit that can synchronize with the Grid and provide its declared capacity for a minimum period of $8\,\text{hours}$; also called Cold Standby Reserve.

Spinning Reserve

The component of Contingency Reserve synchronized to the Grid and ready to take on Load; also called Hot Standby Reserve.

Contingency Reserve

Generating capacity intended to take care of the loss of the largest Synchronized Generating Unit or power import from a single Grid interconnection, whichever is larger; includes Spinning Reserve and Backup Reserve.

Primary Response

The automatic response of a Generating Unit to frequency changes released increasingly from $0\text{ to }5\,\text{s}$ from the time of frequency change, fully available for the next $25\,\text{s}$.

Secondary Response

The automatic response to frequency fully available $25\,\text{s}$ from the time of frequency change to take over from Primary Response, sustainable for at least $30\,\text{min}$.

Blue Alert

A notice issued by the System Operator when a tropical disturbance is expected to make landfall within $24\,\text{hours}$.

Demand Control Imminent Warning

A warning from the System Operator issued when a Demand reduction is expected within the next $30\,\text{minutes}$.

Planned Activity Notice

A notice issued by a User to the Grid Owner and System Operator for any planned activity or shutdown at least $7\,\text{days}$ prior to the actual activity.

Schedule Day

The period from $0000\text{H}$ to $2400\text{H}$ each day.

Critical Loading

The condition when the loading of transmission lines or substation equipment is between $90\%$ and $100\%$ of the continuous rating.

Imminent Overloading

The condition when the loading of transmission lines or substation equipment is above $100\%$ up to $110\%$ of the continuous rating.

Emergency State

The Grid operating condition when a Multiple Outage Contingency has occurred without resulting in Total System Blackout and a generating deficiency exists, voltages are outside $0.90$ to $1.10$, or equipment loading is above $110\%$ of continuous rating.

Low Voltage (LV)

A voltage level not exceeding $1000\,\text{V}$ ($1\,\text{kV}$).

Medium Voltage (MV)

A voltage level exceeding $1\,\text{kV}$ up to $34.5\,\text{kV}$.

High Voltage (HV)

A voltage level exceeding $34.5\,\text{kV}$ up to $230\,\text{kV}$.

Extra High Voltage (EHV)

A voltage level exceeding $230\,\text{kV}$ up to $765\,\text{kV}$.

Overvoltage

A Long Duration Voltage Variation where the RMS value of the voltage is greater than or equal to $110\%$ of the nominal voltage.

Undervoltage

A Long Duration Voltage Variation where the RMS value of the voltage is less than or equal to $90\%$ of the nominal voltage.

Short Duration Voltage Variation

A variation of the RMS value of the voltage from its nominal value for a time greater than one-half cycle of the power frequency but not exceeding $1\,\text{minute}$.

Long Duration Voltage Variation

A variation of the RMS value of the voltage from nominal voltage for a time greater than $1\,\text{minute}$.

Voltage Sag

A Short Duration Voltage Variation where the RMS value of the voltage decreases to between $10\%$ and $90\%$ of nominal voltage; also known as Voltage Dip.

Voltage Swell

A Short Duration Voltage Variation where the RMS value of the voltage increases to between $110\%$ and $180\%$ of nominal voltage.

Voltage Fluctuation

Systematic or random RMS voltage envelope changes where the RMS value of the voltage is between $90\%$ and $110\%$ of the nominal value.

Large Generator

A Generation Company whose generating facility at the Connection Point has an aggregate capacity in excess of $20\,\text{MW}$.

Small Generator

A Generation Company whose generating facility at the Connection Point has an aggregate capacity of $20\,\text{MW}$ or below.

Large Customer

A customer with a demand of at least $1\,\text{MW}$, or the threshold value specified by the ERC.

System Loss

The total Energy injected into the Grid or Distribution System minus the total Energy delivered to Distributors and End-Users.

Technical Loss

The component of System Loss inherent in the physical delivery of electric energy, including conductor loss, transformer core loss, and technical errors in meters.

Non-Technical Loss

The component of System Loss not related to physical electrical characteristics, caused primarily by human error, meter tampering, and erroneous meter reading.

Administrative Loss

The component of System Loss referring to energy used in proper Grid operation (e.g., station service) that is not classified as Technical or Non-Technical Loss.

Total Harmonic Distortion (THD)

The ratio of the root-mean-square value of harmonic content to the root-mean-square value of the fundamental quantity, expressed in percent.

Total Demand Distortion (TDD)

The ratio of the root-mean-square value of harmonic content to the root-mean-square value of the rated or maximum demand fundamental quantity, expressed in percent.

Momentary Average Interruption Frequency Index (MAIFI)

The total number of momentary customer power interruptions within a given period divided by the total number of customers served within the same period.

Negative Sequence Unbalance Factor (NSUF)

The ratio of the magnitude of the negative sequence component of voltages to the magnitude of the positive sequence component, expressed in percent.

Zero-Sequence Unbalance Factor (ZSUF)

The ratio of the magnitude of the zero sequence component of voltages to the magnitude of the positive sequence component, expressed in percent.