Grid Code, Distribution Code, Power System & Electric Power Industry Terms

A complete set of vocabulary flashcards covering power industry terms, grid codes, distribution codes, and recall concepts for RQS preparation.

Fast Start

The capability of a Generating Unit or Generating Plant to start and synchronize with the Grid within 15 minutes.

Backup Reserve

Refers to a Generating Unit that has Fast Start capability and can Synchronize with the Grid to provide its declared capacity for a minimum period of eight (8) hours. Also called Cold Standby Reserve.

Spinning Reserve

The component of Contingency Reserve which is Synchronized to the Grid and ready to take on Load. Also called Hot Standby Reserve.

Contingency Reserve

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

Primary Response

The automatic response of a Generating Unit to Frequency changes release increasingly from zero to five seconds from the time of frequency change, and which is fully available for the next 25 seconds.

Secondary Response

The automatic response to frequency which is fully available 25 second from the time of Frequency change to take over from the Primary Response, and which is sustainable for at least 30 minutes.

Blue Alert

A notice issued by the System Operator when a tropical disturbance is expected to make a landfall within 24 hours.

Demand Control Imminent Warning

A warning from the System Operator, not preceded by any other warning, which is issued when a Demand Reduction is expected within the next 30 minutes.

Planned Activity Notice

A notice issued by a User to the Grid Owner and the System Operator for any planned activity, such as a planned shutdown or Scheduled Maintenance of its Equipment, at least seven (7) days prior to the actual shutdown or maintenance.

Schedule Day

The period from 0000H to 2400H each day.

Critical Loading

Refers to the condition when the loading of transmission lines or substation Equipment is between 90 percent and 100 percent of the continuous rating.

Imminent Overloading

Refers to the condition when the loading of transmission lines or substation Equipment is above 100 percent up to 110 percent of the continuous rating.

Emergency State

The Grid operating condition when a Multiple Outage Contingency has occurred without resulting in Total System Blackout and any of the following conditions is present: (a) generating deficiency exists; (b) Grid transmission voltages are outside the limits of 0.90 and 1.10; or (c) the loading level of any transmission line or substation Equipment is above 110 percent of its continuous rating.

Low Voltage

A voltage level not exceeding 1000 volts.

Medium Voltage (MV)

A voltage level exceeding one (1) kV up to 34.5 kV.

High Voltage (HV)

A voltage level exceeding 34.5 kV up to 230 kV.

Extra High Voltage (EHV)

A voltage level exceeding 230 kV up to 765 kV.

Overvoltage

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

Undervoltage

A Long Duration Voltage Variation where the RMS value of the voltage is less than or equal to 90 percent 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 one minute.

Long Duration Voltage Variation

A variation of the RMS value of the voltage from nominal voltage for a time greater than one (1) minute.

Voltage Sag

A Short Duration Voltage Variation where the RMS value of the voltage decreases to between 10 percent and 90 percent of the nominal value.

Voltage Swell

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

Voltage Fluctuation

The systematic variations of the voltage envelope or random amplitude changes where the RMS value of the voltage is between 90 percent and 110 percent of the nominal value.

Large Generator

A Generation Company whose generating facility at the Connection Point has an aggregate capacity in excess of 20 MW.

Small Generator

A Generation Company whose generating facility at the Connection Point has an aggregate capacity of 20 MW or below.

Large Customer

A Customer with a demand of at least one (1) MW, or the threshold value specified by the ERC.

System Loss

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

Technical Loss

The component of System Loss that is inherent in the physical delivery of electricity Energy. It includes conductor loss, transformer core loss, and technical errors in meters.

Non-Technical Loss

The component of System Loss that is not related to the physical characteristics and functions of the electrical System, and is caused primarily by human error, whether intentional or not. Non-Technical Loss includes the Energy lost due to the tampering of meters and erroneous meter reading.

Administrative Loss

The component of System Loss that refers to the Energy used in the proper operation of the Grid (e.g. station service) that is not classified as Technical Loss or Non-technical Loss.

Total Harmonic Distortion (THD)

The ration of the root-mean-square value of the 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 the 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

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

Zero-Sequence Unbalance Factor

The ratio of the magnitude of the zero-sequence voltage component divided by positive-sequence component, 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 to restore the Grid to its Normal State.

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 of the Grid has Shutdown.

Black Start

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

Isolation

The electrical separation of a part or Component from the rest of the electrical system to ensure when that part or Component is to be maintained or when electric service is not required.

Grounding

A conducting connection by which an electrical circuit or Equipment is connected to earth or to some conducting body of relatively large extent that serves as ground.

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. An Outage may or may not cause an Interruption of service to Customers.

Interruption

The loss of service to a Customer or a group of Customers or other facilities. An Interruption is the result of one or more Component Outages.

Generation Schedule

Refers to the schedule that indicates the hourly output of the Scheduled Generating Units and the list of Generating units that will provide Ancillary Services for the next Schedule Day.

Merit Order Table

Refers to the list showing the offer prices and the corresponding capacity of the Scheduled Generating Units arranged in a manner 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 may be determined by the ERC in accordance with the Act.

Contestable Market

Refers to the electricity End-users who have a choice of a Supplier of electricity, as may be determined by the ERC in accordance with the Act.

Open Access

Refers to the system of allowing any qualified Person the use of transmission, and/or distribution System and associated facilities subject to the payment of transmission and/or distribution retail wheeling rates duly approved by the ERC.

Grid Code

The set of rules, requirements, procedures and standards to ensure the safe, reliable, secured and efficient operation, maintenance, and development of the high voltage backbone Transmission System and its related facilities.

Distribution Code

Refers to a compilation of rules and regulations governing electric utilities in the operation and maintenance of their Distribution System.

Reliability

The probability that a System or Component will perform a required task or mission for a specified time in a specified environment. It is 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 of the System 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 r disturbance.

Accountable Manager

A person who has been duly authorized by the Grid Owner (or a User) to sign the Fixed Asset Boundary Documents on behalf of the Grid Owner (or the User).

Active Energy

The integral of the Active Power with respect to time, measured in Watt-hour (Wh) or multiples thereof. Unless otherwise qualified, the term "Energy" refers to Active Energy.

Alert Warning

A notice issued by the System Operator, including Yellow Alert, Blue Alert, and Red Alert, to notify the Grid Users an alert state exists.

Ancillary Service

Support services such as frequency Regulating and Contingency Reserves, Reactive Power support, and Black Start capability which are necessary to support the transmission capacity and energy that are assential in maintaining Power Quality and the Reliability and Security of the Grid.

Automatic Load Dropping (ALD)

The process of automatically and deliberately removing pre-selected Loads from a power System in response to an abnormal condition in order to maintain the integrity of the System.

Automatic Generation Control (AGC)

The regulation of the power output of Generating Units within a prescribed area in response to a change in system Frequency, tie-line loading, or the relation of these to each other, so as to maintain the System frequency or the establish interchange with other areas within the predetermined limits or both.

Central Dispatch

The process of issuing direct instructions to the electric power industry participants by the System Operator to achieve an economic operation while maintaining Power Quality, Stability, and the Reliability and Security of the Grid.

Demand Side Management (DSM)

Refers to measures undertaken by Distribution Utilities to encourage End-users in the proper management of their load to achieve efficiency in the utilization of fixed infrastructures in the system.

Distribution Utility

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

Embedded Generator

A person or entity that generates electricity using an Embedded Generating Plant.

Expected Energy Not Supplied (EENS)

The expected Energy curtailment due to generating capacity Outages in the specified period.

Fixed Asset Boundary Document

A document containing information and which defines the operational responsibilities for the equipment at the Connection Point.

Flicker

The impression of unsteadiness of visual sensation induced by a light stimulus whose luminance or spectral distribution fluctuates with time.

Forced Outage

An Outage that results from emergency conditions directly associated with a Component, requiring that it be taken out of service immediately, either automatically or as soon as switching operations can be performed. Also, an Outage caused by human error of the improper operation of Equipment.

Grid Impact Studies

A set of technical studies which are used to assess the possible effects of a proposed expansion, reinforcement, or modification of the Grid or a User Development and to evaluate Significant Incidents.

Grid Owner

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

Lifeline Rate

Refers to the subsidized rate given to Marginalized/low-income Captive Market End-users who cannot afford to pay at full cost.

Loss of Load Probability (LOLP)

The expected number of days in a specified period in which the daily peak Demand will exceed the available generating capacity.

Market Operator

An independent group, with equitable representation from Electric Power Industry Participants, whose task includes the operation and administration of the Wholesale Electricity Spot Market in accordance with the Market Rules.

Power Development Program (PDP)

The indicative plan for managing Demand through energy-efficiency programs and for the upgrading, expansion, rehabilitation, repair, and maintenance of power generation and transmission facilities, formulated and updated yearly by the DOE in coordination with generators, the Grid Owner, System Operator, and Distribution Utilities.

Philippine Energy Plan (PEP)

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

Power Sector Assets and Liabilities Management Corporation (PSALM Corp.)

The government-owned and controlled corporation created pursuant to Sec. 49 of the Act, which took ownership of all existing NPC generation assets, liabilities, IPP contracts, real estate and all other disposable assets.

Red Alert

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

Security Red Alert

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

Shutdown

The condition of the Equipment when it is de-energized or disconnected from the System.

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 the Security of the Grid.

Transmission Development Plan (TDP)

The program for expansion, reinforcement, and rehabilitation of the Transmission System which is 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.

Yellow Alert

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