NERC Reliability Coordinator Exam Vocabulary 2023/24 | updated
Accelerating Power - In a GENERATOR, the difference between the MECHANICAL INPUT POWER and the electrical output POWER (assuming no LOSSES). For a GENERATOR's TORQUE ANGLE to change, the GENERATOR must have accelerating POWER.
Accu...
NERC Reliability Coordinator Exam Vocabulary 2023/24 | updated Accelerating Power - In a GENERATOR, the difference between the MECHANICAL INPUT POWER and the electrical output POWER (assuming no LOSSES). For a GENERATOR's TORQUE ANGLE to change, the GENERATOR must have accelerating POWER. Accumulated Inadvertent - The accumulation over t ime of INADVERTENT ENERGY. The accumulated inadvertent account of a BALANCING AUTHORITY represents the amount of excess ENERGY a BALANCING AUTHORITY has either supplied to the INTERCONNECTION or absorbed from the INTERCONNECTION. BALANCING AUTHORITIES moni tor their accumulated inadvertent to ensure the accounts do not grow too large Active Power - The component of the COMPLEX POWER that performs the work. The common unit of active power is the MW and the symbol is "P". Active power is sometimes called REAL POWER. Actual Interchange - The metered INTERCHANGE over a specific INTERCONNECTION between two PHYSICALLY ADJACENT BALANCING AUTHORITIES. Actual Load - The actual MW drawn by a LOAD from the POWER SYSTEM. The actual load will be different from the rate d or NOMINAL LOAD if the LOAD's VOLTAGE or FREQUENCY vary from their NOMINAL values Adequacy - The ability of the electric SYSTEM to supply the aggregate electrical DEMAND and ENERGY requirements of the end -use customers at all times, taking into account SCHEDULED and reasonably expected unSCHEDULEd OUTAGEs of SYSTEM ELEMENTS.ua Adequate Regulating Margin - The minimum on -line CAPACITY that can be increased or decreased to allow the SYSTEM to respond to all reasonable DEMAND changes in order to be incompl iance with the CONTROL PERFORMANCE STANDARDS. Adjacent Balancing Authorities - A BALANCING AUTHORITY AREA that is interconnected to another BALANCING AUTHORITY AREA either directly or via a multi -
party AGREEMENT or TRANSMISSION TARIFF. AGC Pulses - The A GC SYSTEM sends signals to selected (regulating) GENERATORS to adjust their set -points. These signals are sent via telecommunication EQUIPMENT. The signals are often called AGC pulses. Air- Gap - The air space between the ROTOR and STATOR of a motor or GENERATOR. Alternating Current (AC) - In AC SYSTEM the CURRENT and VOLTAGE magnitudes constantly vary or alternate. CURRENT and VOLTAGE magnitudes do not alternate in a DC SYSTEM. Alternator - A Rotating machine whose output is alternating VOLTAGE and CURR ENT Aluminum Cable Steel Reinforced (ACSR) - A common type of TRANSMISSION line CONDUCTOR that comes in many different sizes and designs. The aluminum is the CONDUCTOR and the steel provides strength. Amortisseur Winding - A machine winding consisting of a number of conducting bars attached between the magnetic POLES of the machine's ROTOR. Amortisseur windings may be used as starter windings or to help dampen POWER OSCILLATIONS Ampere (amp) - The unit of measurement for CURRENT flow, often stated as "am p". Amplitute - The value or magnitude that a waveform has at a specific point in time. Analog Electronics - Electronic circuitry in which the magnitudes of quantities are used in a continuous manner to perform functions. For example, input CURRENT value s may be amplified and used to perform work in an analog CIRCUIT. Analog is different than digital in the sense that analog CIRCUITS use VOLTAGE and CURRENT magnitudes continuously while digital CIRCUITS use VOLTAGE and CURRENT to determine the state (on o r off) of ELEMENTS. Ancillary Services (FERC Definition) - Those services that are necessary to support the TRANSMISSION of CAPACITY and ENERGY from RESOURCES to LOADS while maintaining reliable operation of the TRANSMISSION SERVICE PROVIDER's TRANSMISSIO N SYSTEM in accordance with GOOD UTILITY PRACTICE. Angle Instability - The opposite of ANGLE STABILITY. When a POWER SYSTEM loses ANGLE STABILITY it enters a PERIOD of angle instability. An angle unstable SYSTEM has lost some portion of the magnetic bound that holds sections of the POWER SYSTEM in synchronism with one another. Angle Stability - An angle stable POWER SYSTEM is one in which all ELEMENTS of the POWER SYSTEM are bound together via magnetic forces. For example, an angle stable GENERATOR's inte rnal MAGNETIC FIELD rotates in synchronism (in -step) with the MAGNETIC FIELD of the 3Φ POWER SYSTEM to which it connects. Apparent Power - The product of VOLTAGE and CURRENT PHASORS. Apparent power comprises both active and REACTIVE POWER, usually express ed in KILOVOLTAMPEREs (kVA) or megavoltamperes (MVA). Another term for apparent power is COMPLEX POWER. ARC - The discharge of CURRENT through the air or in a gas. Arcing Horns - An enhancement to a DISCONNECT SWITCH to increase the switch's CURRENT inte rrupting capability. Area Control Area (ACE) - The instantaneous difference between net actual and SCHEDULED INTERCHANGE, taking into account the effects of FREQUENCY bias including a correction for meter error. Armature - The component of a machine in w hich the VOLTAGE is induced. In a SYNCHRONOUS GENERATOR the armature is usually the STATOR. The armature winding is wrapped about the armature. Asynchronous - To be OUT -OF-STEP with a reference. An induction GENERATOR is an asynchronous GENERATOR as its ROTOR does not rotate in synchronism with the POWER SYSTEM. Auto-Load - A feature on some GENERATORS that automatically moves the GENERATOR to a TARGET LOAD (MW ) level. Automatic Generation Control (AGC) - EQUIPMENT that automatically adjusts GENERATION in a BALANCING AUTHORITY AREA from a central location to maintain the BALANCING AUTHORITY's INTERCHANGE SCHEDULE plus FREQUENCY BIAS. AGC may also accommodate au tomatic INADVERTENT payback and TIME ERROR CORRECTION. Automatic Operations Systems - SPECIAL PROTECTION SYSTEMS, REMEDIAL ACTION SCHEMEs, or other operating SYSTEMs installed on the electric SYSTEMs that require no intervention on the part of SYSTEM OPER ATORS. Auto-Transformer - A POWER TRANSFORMER with a single coil. The entire coil acts as the PRIMARY WINDING while a portion of the same coil acts as the SECONDARY WINDING. Auxiliary Relay - A RELAY whose function is to supplement the actions of other t ypes of RELAYS. For example, a LOCKOUT RELAY is an auxiliary relay with numerous contacts that each can perform an action. The IEEE has numbers assigned to two types of auxiliary relays; 86 (lock -out) and 94 (tripping). Availability - A measure of time a generating unit, TRANSMISSION line, or other FACILITY is capable of providing service, whether or not it actually is in service. Typically, this measure is expressed as a percent available for the PERIOD under consideration. Available Flowgate Capability ( AFC) - The available CAPACITY in MW or MVA on a FLOWGATE, which a TRANSMISSION SERVICE PROVIDER has determined, is available for sale. The available CAPACITY determined will be dependent on the GENERATION, LOADS and TRANSMISSION configuration assumed for the time period studied and therefore is referred to as a capability. The AFC will account for all thermal, VOLTAGE and STABILITY LIMITS under both pre and post CONTINGENCY conditions, along with any TRM or CBM. There is no one set of SOURCE and SINK point s associated with an AFC. The AFC can be used to determine the amount of MW that can be transferred between a specific set of SOURCE and SINK points with respect to the FLOWGATE, by dividing the AFC by its corresponding PTDF. Available Transfer Capability (ATC) - A measure of the TRANSFER CAPABILITY remaining in the physical TRANSMISSION network for further commercial activity over and above already committed uses. It is defined as TOTAL TRANSFER CAPABILITY less existing TRANSMISSION commitments (including retail customer service), less a CAPACITY BENEFIT MARGIN, less a TRANSMISSION RELIABILITY MARGIN. Avoided Cost - The cost the utility would incur but for the existence of an independent GENERATOR or other ENERGY service option. Avoided cost rates have be en used as the POWER purchase price utilities offer independent suppliers. Back EMF (Conductors Back EMF) - When AC CURRENT flows through a CONDUCTOR an alternating MAGNETIC FIELD is created. This alternating MAGNETIC FIELD induces a VOLTAGE in the CONDUC TOR. The induced VOLTAGE is called the CONDUCTOR'S back EMF. Back -To-Back HVDC - An HVDC SYSTEM in which AC is converted to DC and then immediately back to AC. The HVDC TRANSMISSION path is very short, normally consisting of a short section of buswork. Backup Power - POWER provided by contract to a customer when that customer's normal SOURCE of POWER is not available. Balancing Authority - The responsible ENTITY that integrates resource plans ahead of time, maintains LOADINTERCHANGE -GENERATION balance wi thin a BALANCING AUTHORITY AREA, and supports INTERCONNECTION FREQUENCY in real time. Balancing Authority Area - The collection of GENERATION, TRANSMISSION, and LOADS within the metered boundaries of the BALANCING AUTHORITY. The BALANCING AUTHORITY mainta ins LOAD -RESOURCE balance within this area Bandwidth - The acceptable range of a quantity. For example, if it is desired to hold the VOLTAGE at a 345 kV BUS between 355 and 360 kV then the bandwidth is 355 - 360 kV or 5 kV. Banking - ENERGY delivered or received by a utility with the intent that it will be returned in kind (as ENERGY) in the future. Base Load - The minimum amount of electric POWER delivered or required over a given period at a constant rate. Base Load Capacity - CAPACITY used to serve a n essentially constant level of customer DEMAND. Base load generating units typically operate whenever they are available, and they generally have a CAPACITY FACTOR that is above 60%. Base Load Generating Units - GENERATORs that normally run continuously to serve a BALANCING AUTHORITY'S LOAD. Bilateral Payback - INADVERTENT INTERCHANGE accumulations paid back via an INTERCHANGE SCHEDULE with another BALANCING AUTHORITY. Bipolar HVDC - An HVDC SYSTEM that uses two CONDUCTORS. One CONDUCTOR is energized wi th a positive VOLTAGE and the other a negative VOLTAGE. Black -Start Unit (BSU) - A generating unit that has the ability to go from a shutdown condition to an operating condition and start delivering POWER without assistance from the POWER SYSTEM the GENER ATOR normally connects to. Blackstart Capability Plan - A documented procedure for a generating unit or STATION to go from a shutdown condition to an operating condition delivering electric POWER without assistance from the ELECTRIC SYSTEM. This procedure is only a portion of an overall SYSTEM RESTORATION plan. Blade (Steam) - The component of a steam TURBINE upon which the steam impacts. Blades are also called "buckets". Blocked Governor - A GOVERNOR CONTROL SYSTEM that has somehow been blocked or preve nted from responding to a FREQUENCY DEVIATION. There are many ways to block a governor. Boiler - The component of a steam POWER plant in which the steam is created. Boiler Follow - A MODE of operation of a fossil unit's TURBINE/BOILER CONTROL SYSTEM in w hich the unit's TURBINE is allowed to immediately respond to a LOAD (MW) change request while the BOILER response "follows" with the resulting temperature and pressure swings. Braking Resistor - A device used to enhance the angle stability of a power syst em that uses hydro -electric generation. A Braking Resistor is a large resistive load that is inserted to absorb excess energy when an accelerating condition is detected in the power system. Broker - A third party who establishes a TRANSACTION between a seller and a purchaser. A Broker does not take title to CAPACITY or ENERGY. Brush - A sliding contact, usually made of carbon, located between the excitation CURRENT SOURCE and the ROTOR FIELD WINDING leads of a SYNCHRONOUS GENERATOR.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller STUVATE. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.49. You're not tied to anything after your purchase.
