Consider a system consisting of a synchronous generator working at a l...
Sync. Generator with lagging PF ⇒ supply P & Q
Sync. Motor with over excitation ⇒ supply Q
Induction motor ⇒ Absorbs Q
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Consider a system consisting of a synchronous generator working at a l...
Reactive Power in the System:
Reactive power is the power that oscillates between the source and the load without being consumed. It is necessary for the operation of inductive and capacitive loads. In power systems, reactive power is measured in volt-amperes reactive (VAr).
Power Factor:
Power factor is the ratio of real power (measured in watts) to apparent power (measured in volt-amperes). It indicates the efficiency of a power system. A lagging power factor indicates that the load is inductive, while a leading power factor indicates that the load is capacitive.
System Components:
1. Synchronous Generator: A synchronous generator is a device that converts mechanical energy into electrical energy. It operates at a lagging power factor, which means it consumes reactive power.
2. Synchronous Motor: A synchronous motor is a device that converts electrical energy into mechanical energy. It operates at an overexcited condition, which means it generates reactive power.
3. Induction Generator: An induction generator is a device that converts mechanical energy into electrical energy. It is directly grid-connected, which means it operates at the same frequency and voltage as the grid. It consumes reactive power.
Analysis of Statements:
a) Synchronous motor and synchronous generator are sources, and induction generator is a sink of reactive power.
In this statement, the synchronous motor generates reactive power, and the synchronous generator consumes reactive power. The induction generator is a sink of reactive power.
b) Synchronous motor and induction generator are sources, and synchronous generator is a sink of reactive power.
In this statement, the synchronous motor generates reactive power, and the induction generator also generates reactive power. However, the synchronous generator consumes reactive power.
c) Synchronous motor is a source, and induction generator and synchronous generator are sinks of reactive power.
In this statement, the synchronous motor generates reactive power. Both the induction generator and synchronous generator consume reactive power.
d) All the sources of reactive power.
This statement implies that all the components in the system are sources of reactive power, which is not true.
Correct Answer:
The correct answer is option 'a' - Synchronous motor and synchronous generator are sources, and induction generator is a sink of reactive power. This statement correctly identifies the reactive power generation and consumption characteristics of the system components.