1.
A combined-cycle generator has a heat rate of
Correct Answer
A. 7000
Explanation
The heat rate of a combined-cycle generator refers to the amount of heat energy required to produce one unit of electricity. A lower heat rate indicates higher efficiency, as less heat energy is wasted. Therefore, a heat rate of 7000 suggests that this particular combined-cycle generator is more efficient compared to the other options provided (9000, 12500, and 14000).
2.
Inadvertent interchange is the difference between the net actual interchange and net scheduled interchange.
Correct Answer
A. True
Explanation
The statement is true because inadvertent interchange refers to the difference between the net actual interchange (the actual amount of electricity transferred between two systems) and the net scheduled interchange (the planned or scheduled amount of electricity transfer). Inadvertent interchange occurs when there is an unintentional deviation from the scheduled interchange, resulting in a difference between the planned and actual amount of electricity exchanged.
3.
Inadvertent interchange is the difference between forecast and actual energy interchanged.
Correct Answer
B. False
Explanation
The statement is false because inadvertent interchange refers to the difference between actual energy interchanged and the scheduled or contracted energy interchanged, not the forecasted energy. Therefore, the given statement is incorrect.
4.
Systems are operating in Parallel. System A schedules 100MW into B. B does not reduce generation as A schedules, What happens?
Correct Answer
A. Frequency in B increases
Explanation
If there is a power imbalance, frequency excursions occur: o When the system is over generating (supply> demand), the frequency increases above 60 Hz, o When the system is under-generating (supply
5.
Ln power system stability, the use of the equal-area criterion involves
Correct Answer
B. Power vs power angle
Explanation
The use of the equal-area criterion in power system stability involves analyzing the relationship between power and power angle. This criterion is used to determine the stability of a power system by comparing the areas under the power-angle curve before and after a disturbance. If the areas are equal, the system is considered stable. Therefore, understanding the power-angle relationship is crucial in assessing the stability of a power system.
6.
The angle between the source and the load voltages of a transmission system is called
Correct Answer
A. Power angle
Explanation
The angle between the source and the load voltages of a transmission system is called the power angle. This angle represents the phase difference between the source voltage and the load voltage and is important in determining the flow of power in the system. A larger power angle indicates a higher flow of power from the source to the load, while a smaller power angle indicates a lower flow of power.
7.
Power flows between interconnected system from a _____
Correct Answer
A. Leading power angle
Explanation
Power flows from a system with a leading power angle to a system with a lagging power angle. A leading power angle means that the current is leading the voltage in phase, indicating a capacitive load. In this case, the power is flowing from the system with the leading power angle to the system with the lagging power angle, where the current lags behind the voltage, indicating an inductive load.
8.
Maximum power flows when the power transfer angle is zero.
Correct Answer
B. False
Explanation
The statement is false because maximum power flows when the power transfer angle is 90 degrees, not zero. At a power transfer angle of zero degrees, the power flow is minimum. As the power transfer angle increases from zero, the power flow also increases until it reaches a maximum at 90 degrees. After 90 degrees, the power flow starts to decrease. Therefore, the correct answer is false.
9.
Which is a way of increasing real power flow:
Correct Answer
D. All of the above
Explanation
All of the above options can be used to increase real power flow. Changing the phase angle with phase-shifting transformers allows for better utilization of the transmission lines by adjusting the power flow direction. Changing generation patterns relative to the line terminals involves adjusting the output of power plants to match the load requirements, thereby increasing power flow. Changing the impedance of the line with series capacitors helps to reduce the reactance of the line, allowing for more power to be transferred.
10.
In interconnected systems power flows from the system with the:
Correct Answer
A. Greater leading power angle
Explanation
In interconnected systems, power flows from the system with the greater leading power angle. This is because the leading power angle represents the phase difference between the voltage and current in a power system. A greater leading power angle indicates that the voltage leads the current, which means that the system is generating more power than it is consuming. Therefore, power flows from this system to the system with a lesser leading power angle, where the voltage lags behind the current.
11.
What is common between demand factor and diversity factor?
Correct Answer
A. Maximum demand
Explanation
Demand factor and diversity factor are both used in electrical engineering to determine the maximum demand on a power system. The demand factor is the ratio of the maximum demand of a system to the total connected load, while the diversity factor is the ratio of the sum of the individual maximum demands to the total connected load. Both factors help in determining the maximum demand that a power system can handle, taking into account the variations in load and the likelihood of all loads being used simultaneously. Therefore, the common factor between demand factor and diversity factor is the concept of maximum demand.
12.
The Department's heart rate for the newly combined cycle in BTU is:
Correct Answer
A. 7000
Explanation
The Department's heart rate for the newly combined cycle in BTU is 7000.
13.
What is automated using the automatic controls of power stations?
Correct Answer
C. All of the above
Explanation
The automatic controls of power stations are responsible for automating various tasks and processes within the station. This includes achieving full control of the station, allowing operators to remotely monitor and control different aspects of the power generation process. Additionally, the automatic controls also play a crucial role in ensuring the safety and reliability of the power station by implementing an emergency protection system. Therefore, the correct answer is "All of the above" as both full control of the station and the emergency protection system are automated using these controls.
14.
LADWP'S average load is:
Correct Answer
A. 3500
Explanation
The correct answer is 3500 because it is stated that "LADWP's average load is" and out of the given options, 3500 is the only value that matches this statement.
15.
Spinning reserve is an unloaded generation which is synchronized and capable of serving additional demand in ___ minutes.
Correct Answer
B. 10
Explanation
Spinning reserve refers to the unused generation capacity that is synchronized with the power grid and can quickly be activated to meet any additional demand within a certain timeframe. In this case, the correct answer is 10 minutes, indicating that the spinning reserve can be brought online and start serving the additional demand within 10 minutes.
16.
The departments operating reserve is:
Correct Answer
D. Single failure contingency plus regulation
Explanation
The operating reserve refers to the extra capacity that a power system needs to have in order to handle unexpected events, such as equipment failures or sudden changes in demand. The single failure contingency plus regulation is a measure that takes into account the possibility of a single equipment failure and the need for regulation services to maintain system stability. This means that the operating reserve includes both the capacity needed to handle a single failure and the capacity needed for regulation services.
17.
Which type of reliability indices is for momentary interruptions?
Correct Answer
D. MAIFI
Explanation
MAIFI stands for Momentary Average Interruption Frequency Index. It is a reliability index that measures the average frequency of momentary interruptions in a power system. Momentary interruptions are brief interruptions in power supply that last for a very short duration, typically less than 5 minutes. MAIFI is used to assess the reliability of the power system in terms of momentary interruptions and is an important metric for utility companies to monitor and improve the quality of their service.
18.
Maximum power flows when the power transfer angle is____
Correct Answer
A. 90
Explanation
When the power transfer angle is 90 degrees, it means that the sending and receiving ends of the power system are completely out of phase. This results in the maximum power flow because the voltage difference between the two ends is at its highest, allowing for maximum power transfer. In contrast, at angles other than 90 degrees, the power flow is reduced due to a decrease in the voltage difference. Therefore, the maximum power flows when the power transfer angle is 90 degrees.
19.
They cancel some of the inductive reactance of a line, therefore, decreasing impedance. This enables more real power to flow. They are used primarily to improve system stability.
Correct Answer
C. Series Capacitors
Explanation
Series capacitors are used to cancel some of the inductive reactance of a line, which reduces the overall impedance. By decreasing impedance, series capacitors enable more real power to flow through the line. Additionally, series capacitors are primarily used to improve system stability.
20.
During light loads, the capacitive charging current may cause the excessive voltage at the receiving end of a transmission line. These are switched in and out of service to absorb excess VARS during lightly loaded periods.
Correct Answer
A. Shunt Reactors
Explanation
During light loads, the capacitive charging current in a transmission line can cause excessive voltage at the receiving end. Shunt reactors are used to absorb excess VARS (volt-ampere reactive) during lightly loaded periods. Shunt reactors are connected in parallel with the transmission line and provide inductive reactance, which helps to balance the capacitive reactance caused by the line. This helps to regulate the voltage and prevent it from becoming too high. Shunt capacitors, on the other hand, are used to compensate for lagging power factor and improve system efficiency. Series capacitors are used to compensate for the inductive reactance of the line and improve transmission capacity.
21.
Switching these into service compensates for this effect by adding Var load to the system. They are also attached to the tertiary windings of a transformer bank.
Correct Answer
A. Shunt Reactors
Explanation
Shunt reactors are used to compensate for the effect of switching by adding Var load to the system. They are also attached to the tertiary windings of a transformer bank. Shunt reactors help to stabilize the voltage and reduce the reactive power in the system, improving the overall efficiency and reliability of the electrical network.
22.
If a line is heavily loaded, the inductive Var losses may cause the insufficient voltage at the receiving end of a transmission line. These compensate for this effect. In the morning when customer loads are increasing they are swithced into service to supplies VARS.
Correct Answer
B. Shunt Capacitors
Explanation
Shunt capacitors are used to compensate for the inductive VAR losses in heavily loaded transmission lines. When a line is heavily loaded, the inductive VAR losses can cause a drop in voltage at the receiving end. Shunt capacitors are switched into service in the morning when customer loads are increasing to supply VARs and maintain the voltage levels within acceptable limits.
23.
Turning these on adds voltage to the system, and therefore they are placed as close to the load as practical.
Correct Answer
B. Shunt Capacitors
Explanation
Shunt capacitors are placed as close to the load as practical because they add voltage to the system. By adding voltage, they help to improve the power factor and compensate for reactive power in the system. This improves the efficiency of the system and reduces losses. Shunt capacitors are commonly used in power systems to regulate voltage and improve power quality.
24.
Responds only to frequency changes. It does not respond to power flow changes on tie lines. This mode is used only on an isolated system since it could lead to overloading ties lines while correcting frequency in all interconnected systems.
Correct Answer
D. Frequency line bias (Flat frequency control)
Explanation
Frequency line bias, also known as flat frequency control, is the correct answer. This mode only responds to frequency changes and does not take into account power flow changes on tie lines. It is used only on isolated systems to avoid overloading tie lines while correcting frequency in all interconnected systems.
25.
It uses frequency and tie-line power flow to calculate ACE. A more descriptive term for this control mode is a constant net interchange with frequency bias.
Correct Answer
B. Tie line bias with frequency control (Tie line bias control)
Explanation
The correct answer is Tie line bias with frequency control (Tie line bias control). This control mode uses frequency and tie-line power flow to calculate ACE (Area Control Error), which is the difference between the scheduled and actual interchange power. It is also known as a constant net interchange with frequency bias, indicating that the control mode aims to maintain a constant net interchange while considering the frequency of the power system.
26.
In Tie line bias control:
lf frequency decreases and the power leaving the system decreases or power entering the system increases, then the need for power _____
Correct Answer
B. Inside the BA
Explanation
When the frequency decreases and the power leaving the system decreases or power entering the system increases, it means that there is a surplus of power within the system. In Tie line bias control, the surplus power can be redirected and utilized within the Balancing Authority (BA) region. Therefore, the need for power is inside the BA.
27.
In Tie line bias control:
If frequency decreases and the power leaving the system increases or power entering the system decreases then the need for power ____
Correct Answer
A. Outside the BA
Explanation
In tie line bias control, if the frequency decreases and the power leaving the system increases or power entering the system decreases, it indicates that there is excess power in the system. This excess power needs to be transferred outside the Balancing Authority (BA) to maintain system stability. Therefore, the need for power is outside the BA.
28.
If a system is over generating what happens:
Correct Answer
C. Frequency goes up
Explanation
When a system is over generating, it means that it is producing more power than is required. In such a situation, the frequency of the system increases. This is because the excess power being generated causes the rotational speed of the generator to increase, leading to an increase in the frequency of the alternating current produced.
29.
If a system is under generating what happens?
Correct Answer
D. Frequency goes down
Explanation
When a system is under generating, it means that it is not producing enough power to meet the demand. In such a situation, the frequency of the system decreases. This is because the frequency of an electrical system is directly proportional to the speed of rotation of the generator. When the generator is under generating, it slows down, causing the frequency to decrease.
30.
Is a measure of the probability that a particular piece of equipment will turn on coincidentally to another piece of equipment. For aggregate systems, it is defined as the ratio of the sum of the individual non-coincident maximum loads of various subdivisions of the system to the maximum demand of the complete system.
Correct Answer
A. Diversity Factor
Explanation
The diversity factor is a measure of the probability that a particular piece of equipment will turn on coincidentally to another piece of equipment. It is calculated by dividing the sum of the individual non-coincident maximum loads of various subdivisions of the system by the maximum demand of the complete system. This factor helps in determining the overall load on the system and understanding the likelihood of multiple equipment operating simultaneously.
31.
It is defined as the average load divided by the peak load in a specified time period.
Correct Answer
E. Load Factor
Explanation
Load factor is a measure that represents the average load on a system divided by the peak load during a specific time period. It provides insight into how efficiently a system is being utilized. A higher load factor indicates that the system is being used closer to its full capacity, while a lower load factor suggests that there is more unused capacity. Therefore, load factor is an important metric for understanding the efficiency and utilization of a system or network.
32.
Is the ratio of the time that a piece of equipment is in use to the total time that it could be in use. It is often averaged over time in the definition such that the ratio becomes the amount of energy used divided by the maximum possible to be used. These definitions are equivalent.
Correct Answer
D. Utilization Factor
Explanation
The utilization factor refers to the ratio of the time that a piece of equipment is in use to the total time that it could be in use. It is often expressed as the amount of energy used divided by the maximum possible energy that could be used. This factor provides a measure of how effectively and efficiently the equipment is being utilized. It is commonly used in various industries to assess the performance and efficiency of equipment or systems.
33.
Is used to refer to the fractional amount of some quantity being used relative to the maximum amount that could be used by the same system. The demand factor is always less than or equal to one. As the amount of demand is a time-dependent quantity so is the demand factor.
Correct Answer
B. Demand Factor
Explanation
The demand factor is used to measure the fractional amount of a quantity being used relative to the maximum amount that could be used by the same system. It is always less than or equal to one because it represents the proportion of the maximum demand that is actually being utilized. Since the amount of demand is a time-dependent quantity, the demand factor also varies over time.
34.
Is the ratio of its actual output over a period of time, to its potential output if it were possible for it to operate at full nameplate capacity indefinitely.
Correct Answer
C. Capacity Factor
Explanation
Capacity factor is the ratio of the actual output of a system or device over a specific period of time, to its potential output if it were operating at maximum capacity continuously. It represents the efficiency and utilization of the system or device. A higher capacity factor indicates that the system or device is being utilized more effectively, while a lower capacity factor indicates that it is not being fully utilized.
35.
SAIDE is
Correct Answer
C. The sum of duration of all outages over the total number of incidents
Explanation
*##*(A reliability indicator by electric power utilities. It is also described as the average outage duration for each customer served.)*##*ccvcv
36.
Which is not a cause of inadvertent interchange.
Correct Answer
E. High load flows
Explanation
High load flows can cause inadvertent interchange. In a power system, high load flows refer to the situation where the demand for electricity is higher than the available supply. This can lead to imbalances in the system and result in unintentional interchange between different regions or areas. Inadvertent interchange occurs when electricity flows from one area to another without being intentionally scheduled or accounted for. Therefore, high load flows can be a cause of inadvertent interchange.
37.
Department Power system's heart rate:
Correct Answer
A. 8000
Explanation
The given values represent the heart rate of the Power system department. The answer of 8000 indicates that the heart rate is at a lower level compared to the other values. This suggests that the department may be experiencing lower levels of activity or stress compared to the other options provided.
38.
Castaic can be changed from full pumping to full generation is; what amount of time?
Correct Answer
A. Less than 20 minutes
Explanation
The correct answer is "Less than 20 minutes" because it implies that the process of changing from full pumping to full generation at Castaic takes a relatively short amount of time. This suggests that the infrastructure and mechanisms in place for this transition are efficient and can be quickly adjusted.
39.
Percent the Department use Coal to produce energy:
Correct Answer
C. 4-%
40.
The amount of spinning reserve on average available by LADWP'S units is:
Correct Answer
D. Single failure contingency plus regulation
Explanation
Assuming an average peak load of 3500 and assuming all of Castaic (1250) is available which can all be counted for spin plus some Hoover (350-450) plus some small amount from other units.
41.
This bias technique responds only to changes in power flow on tie lines. It does not respond to frequency changes; To prevent large frequency deviations, it is used only for brief periods when a frequency measurement is not available.
Correct Answer
C. Flat tie line bias (Flat tie line control)
Explanation
The correct answer is Flat tie line bias (Flat tie line control). This bias technique only reacts to changes in power flow on tie lines and does not respond to frequency changes. It is used for brief periods when a frequency measurement is not available, to prevent large frequency deviations.
42.
A normal mode of Automatic Generation Control that allows the Balancing Authority to maintain its Interchange Schedule and respond to the Interconnection frequency error.
Correct Answer
B. Tie line bias with frequency control (Tie line bias control)
Explanation
Tie line bias with frequency control, also known as tie line bias control, is a normal mode of Automatic Generation Control that allows the Balancing Authority to maintain its Interchange Schedule and respond to the Interconnection frequency error. This control mode adjusts the power flow on tie lines between different control areas to help maintain the desired frequency and balance the generation and load within the interconnected system. It uses bias control to allocate generation resources based on the frequency deviation, ensuring that the power flow is adjusted in a way that helps stabilize the system frequency.
43.
To calculate Load Factor and Diversity Factor, you need the:
Correct Answer
C. The peak load of the system
Explanation
To calculate Load Factor and Diversity Factor, the peak load of the system is required. The peak load represents the maximum demand on the system during a specific period of time. Load Factor is calculated by dividing the average load by the peak load, and it indicates the average utilization of the system over a given period. Diversity Factor, on the other hand, is calculated by dividing the sum of maximum demands of different feeders by the peak load, and it represents the ratio of the sum of individual maximum demands to the peak demand of the system. Therefore, the peak load of the system is essential in determining both Load Factor and Diversity Factor.
44.
The sum of each feeder's maximum demand is greater than the total maximum demand in a distribution station. This is caused by the:
Correct Answer
B. Diversity Factor
Explanation
The correct answer is Diversity Factor. The diversity factor refers to the ratio of the sum of individual maximum demands to the total maximum demand. In a distribution station, different feeders or circuits may have different maximum demands at different times. When these individual maximum demands are added up, they can be greater than the total maximum demand because not all feeders will have their maximum demand at the same time. This is known as the diversity factor and is the reason why the sum of each feeder's maximum demand can be greater than the total maximum demand in a distribution station.
45.
In unbalance fault which statement about the zero impedance is false:
Correct Answer
A. Zero sequence voltage from line to neutral is always zero
Explanation
The statement that zero sequence voltage from line to neutral is always zero is false. In an unbalance fault, zero sequence voltage from line to neutral can have a non-zero value.
46.
In the operation and application of Automatic Generation Control (AGC), the system is to control the area with the load/frequency control? What would you use?
Correct Answer
B. Tie line bias with frequency control
Explanation
In the operation and application of Automatic Generation Control (AGC), tie line bias with frequency control is used to control the area with the load/frequency control. This technique involves adjusting the power flow between interconnected areas through tie lines based on the frequency deviation. By biasing the power flow in this way, the AGC system can help maintain the desired frequency and load balance in the interconnected power system.
47.
The purpose of the AGC function is?
Correct Answer
A. Match generation to load
Explanation
The purpose of the AGC function is to match generation to load. This means that it helps in maintaining a balance between the amount of electricity being generated and the amount of electricity being consumed by the load. The AGC function continuously monitors the load and adjusts the generation accordingly to ensure that there is neither an excess nor a shortage of electricity. This helps in maintaining the stability and reliability of the power system.
48.
Speed droop of a hydro generator is defined as:
Correct Answer
C. The percentage of speed change from normal speed at no load to full load
Explanation
Speed droop=No Load%/Full Load%
49.
Whether the synchronous machine operates as a generator or a motor depends on:
Correct Answer
B. Overexciting or under-exciting the stator
Explanation
f-machine< f-system =motor
f-machine> f-system =generator
50.
Thermal plants on the department's system are usually operated to:
Correct Answer
A. Minimize fuel use
Explanation
Thermal plants on the department's system are usually operated to minimize fuel use because this helps in reducing operational costs and conserving natural resources. By optimizing fuel consumption, the plants can generate electricity efficiently and sustainably. This approach aligns with the goal of minimizing environmental impact and promoting energy conservation.