S4 - Reactive Power Flashcards
The commonly used term for the electrical potential difference between two points across an element
Voltage
Voltages at higher levels, such as 4,000 volts and higher. Distributors own and operate most of the lines built at high voltages. It allows distributors to run lines longer distances and serve more customers
Primary Voltage
Voltages at lower levels, or the voltages that are actually used inside buildings by customers, such as 120 volts or 480 volts
Secondary Voltages
The rate of flow of electric charge in a conductor between two points having a difference in potential.
Current
The total opposition offered by an electric circuit to the flow of an alternating current. It is a combination of resistance and reactance, measured in ohms
Impedance
This can affect the power flow, voltage drop, the available fault currents, and losses in a circuit
Impedance
The current through a conductor between two points is directly proportional to the potential difference or voltage across the two points, and inversely proportional to the resistance between them
Ohm’s Law
On this circuits with a multi-grounded neutral, the neutral normally carries 40 to 60% of the current
Single Phase Circuits
This type of phase utilizes a single phase conductor and single neutral
Single Phase
In this phasing the neutral may carry up to 50% of the current.
Two Phase
This type of phase utilizes two phase conductors and a single neutral
Two Phase
In this phasing with a balanced load, the neutral carries almost no current.
Three Phase Four Wire
In this phasing with an unbalanced load, the neutral carries approximately the difference between the high phase current and the low phase current.
Three Phase Four Wire
This type of phase utilizes three phase conductors and a single neutral, or a four-wire multi-grounded system.
Three Phase Four Wire
This type of phase utilizes three wire systems with no neutral.
Three Phase Three Wire
On this phase, single-phase loads are connected phase to phase lines have two of the three phase conductors.
Three Phase Three Wire
The difference between the high phase amps and the low phase amps, as long as the power factor is similar on all three phases
Approximate Neutral Current
The is the power used by loads to do work.
Real Power
The is the capacity that EPB has to provide
Apparent Power
The closer EPB can equalize ________ to _____, the more efficient the power system becomes
Apparent Power (S) to Real Power (P)
The ratio of the Real Power to Apparent Power
Power Factor
Measures the delay between when the voltage pushes the electrons and when they actually begin to flow
Power Factor
Defines both, how much of a delay there is and, more importantly, what percentage of the current is actually doing work
Power Factor
The magnetizing component of power required by the circuit. It is necessary to establish the magnetic flux and is referred to as VARS. It can be supplied by a motor or generator.
Reactive Power
On an electric system with no power factor correction, does the current lag the voltage or does voltage lag the current?
Current lags Voltage
What is a “perfect” power factor?
1 or 100%
The amount of power consumed on a power system
Load
The amount of _____ changes based on numerous factors that include weather, processes and activity of customers, and addition of new customers
Load
The total Energy consumed over a period of time is measured in this unit.
Kilo-Watt-Hours
The greatest of all demands which have occurred during the specific interval of time
Maximum Demand
The ratio of the corresponding maximum demand of two or more loads to the sum of the non-coincident maximum demand for these loads for a given period
Coincident Factor
The ratio of the average load over a designated period of time to the peak load occurring in that interval
Load Factor
Indicates the amount of usage of the system’s equipment and is a measurement of efficiency
Load Factor
Occurs when one or more electrical conductors contact ground and/or each other
Faults
The electrical current that flows through a circuit during an electrical fault condition.
Fault Current
Several times larger in magnitude than the current that normally flows through a circuit.
Fault Current
One phase conductor makes contact with the ground
Single Line to Ground Faults
Two phase conductors make contact with the ground
Double Line to Ground Faults
Three phase conductors make contact with the ground
Three Phase Faults
The phase conductor makes contact with another item, such as a tree, ice, or other high impedance path to ground
High-Impedance Faults
-Fault current flows from the source through the single path to the location of the fault
Radial
-Has two or more sources
-Faults results in all sourse breakers operating
-Fault current flows from all sources through separate paths to the location of the fault
Loop
