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NERC SOS Pre-Assessment Exam (202 5 ) | Actual Questions and Answers
Latest Updated 202 5 /202 6 (Graded A+)
What are three primary AGC control models? - ✔✔Tie-Line Bias, Constant Frequency, Constant Net Interchange When a balancing Authority's ACE is zero, what is true? - ✔✔The BA load-interchange-generation balancing while supporting Interconnection Frequency In a 3 - phase AC generator... - ✔✔Each phase is physically offset by 120 degrees Inductance is a property of an electric circuit that opposes the change in - ✔✔current What three values are included in OHM's Law? - ✔✔Volts, Amps, impedance You dispatch a field crew to a substation to help determine the reason for a transmission line trip. What is the first thing you are going to ask them to do? - ✔✔Read Targets When energizing a long, HV transmission line from one end, what would you expect to see on the open end of the line? - ✔✔Higher Voltage than the closed end What is inadvertent? - ✔✔The difference between actual and scheduled interchange What is a balancing area between the source and sink balancing areas called? - ✔✔Intermediary Balancing Area What does AGC stand for? - ✔✔Automatic Generation Control
When implementing an interchange schedule, what tool is used to document and distribute the information associated with the transaction? - ✔✔E-Tag In order for a generator to produce megawatts, it must have a - ✔✔torque Angle On an electric generator, what does the term "Ramp Rate" Mean? - ✔✔The generators ability to increase or decrease MW output over a given period of time Low Voltage is an indication there is - ✔✔A Deficiency in reactive power Power System elements that absorb or use reactive power (VARS) Are: - ✔✔Under-excited generators, synchronous condensors, shunt reactors & motor loads What does MVA stand for> - ✔✔Mega-Volt Amps What is one advantage of transmitting power at higher voltage levels? - ✔✔Losses are reduced Three types of steam generating Units are: - ✔✔Fossil Feed units, nuclear units and geothermal units What is the purpose of a distribution transformer? - ✔✔To transform voltage from the transmission level to the distribution level What are the 3 types of substation configurations? - ✔✔Ring bus, breaker and a half, doubles bus- double breaker What does the b stand for in the ACE equation? - ✔✔Bias What is the result of energizing a cap bank? - ✔✔Increase Voltage
What is the primary source of voltage in an electric power system? - ✔✔Generator What two substances are generally used for transformer cooling? - ✔✔Oil and air Capacitance in a property of an electric circuit that opposes change in - ✔✔Voltage What does the term System fault mean? - ✔✔A physical condition that causes a device, component or element to fail in performing in its intended manner What component in a power plant is most impacted by frequency deviations? - ✔✔Low Pressure turbine blades What's a good example of an inductive load? - ✔✔Motors What are four causes of inadvertent? - ✔✔1. Bias response to frequency
- AGC lag
- Meter Errors
- Scheduling Errors When the total generation in an interconnection is more than the total load of the interconnection
- ✔✔Frequency will be above 60 HZ Automatic generation increases due to a frequency decrease is the result of - ✔✔Generator Governor Action . A component of an electrical power system that can function as a motor or as a VAR generator is called a: - ✔✔Synchronous Condenser What is the action of voltage reduction? - ✔✔Voltage is manually reduced by the SO
Generator governor systems are designed to do what? - ✔✔Arrest declining frequency What is the most common limiting factor of a transmissions lines ability to carry load? - ✔✔Thermal What is the purpose of a systems protection system? - ✔✔To detect faults and clear the faults as quick as possible On transformer ratings, what does FOA stand for? - ✔✔Forced Oil and air What does the formula I^2 R indicate>? - ✔✔Losses What is EMS? - ✔✔Energy Management System What is the purpose of the air in a high voltage air circuit breaker? - ✔✔To extinguish the arc when opening the breaker If current in an Ac circuit is doubled, losses in that circuit will be - ✔✔Four times greater An interchange schedule can only be between... - ✔✔Adjusting BA's What does the term economic dispatch stand for? - ✔✔Disturbing the system total generation requirements among on-line generating units to obtain optimum system security What determines the size of insulators used on power lines? - ✔✔Voltage level An interchange transaction is between - ✔✔Source and sink BA's What NERC control performance measures a balancing areas ability to regulate its generation to match their load in real time? - ✔✔CPS 1 & 2
The primary purpose of the electric transmission system is to: - ✔✔Transmit high voltage power from one point on the system to another An electric generator consists of a... - ✔✔Rotor and a stator Three components of a System Protection System are: - ✔✔Measuring devices, protection relays and control circuitry What does the term "Loop flows" mean? - ✔✔Power flows on paths as result of energy transfers What is spinning reserves? - ✔✔Delivering VARS to the system and is lagging Power system elements that are sources of reactive power (VARS) include: - ✔✔Over-excited generators shunt capacitors and line capacitance What is a situation that could require manual load shedding? - ✔✔Not enough generation When a generator is over-excited, it is... - ✔✔Delivering VARS to the system and is lagging What does the term "Surge Impedance Loading" refer to? - ✔✔The loading point of a transmission line when the line is neither inductive or capacitive When a transmission line is absorbing VARs from the system, the line is considered to be... - ✔✔inductive What is the purpose of a Transaction Tag? - ✔✔To provide info to party's involved in the transaction and to inform the RC of transactions affecting constraint points The MVA of a power system component is determined by its - ✔✔MW's and MVAR's
What does a generators governor droop setting determine? - ✔✔The percentage the frequency has to change to increase the output of the generating unit from no load to full load or full load to no load When two systems are to be "synchronized", what three things must be matched? - ✔✔- Frequency, phase angle and voltage magnitude In most high voltage power systems, how many phases are there? - ✔✔ 3 pee circuit In most high voltage power systems, how many phases are there? - ✔✔ 3 per circuit What is the purpose of a steam generator? - ✔✔to create steam to drive a turbine When isolating equipment in the electrical system, what device is most often used for clearance points?
- ✔✔disconnect switches An interchange schedule is between... - ✔✔sending and receiving BA's What is the purpose of the DC current flowing through the rotor of an electric generator? - ✔✔To induce a field which will create an electromagnet A balancing area has the following readings, NIA = 100, NIS = 50, Frequency is 59.95, their bias is - 50/. hz. What is their ACE? - ✔✔+ As current on a conductor increases, temperature of the conductor... - ✔✔Increases The forced outage of electrical equipment is called... - ✔✔Contingency What is the primary purpose of a current transformer? - ✔✔To reduce the current to instrument levels
