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Gusman · 61-69, M
@FoleysFollies Excellent. For tonight sleep inducement.
Synchronization of Generators
Often electrical generators are removed from the service and connected back to the power system during variations of the load, emergency outages, maintenance, etc.
Before reconnecting the generator to the system in each time, it must be synchronized with parameters of the power system network.
An improper synchronization can affect the healthy power system and results in electrical and mechanical transients that can damage the prime mover, generator, transformers and other power system components.
What is Synchronization of Generators?
The process of matching parameters such as voltage, frequency, phase angle, phase sequence and waveform of alternator (generator) or other source with a healthy or running power system is called synchronization.
Generator cannot deliver power to electric power system unless its voltage, frequency and other parameters are exactly matched with the network. Synchronization is accomplished by controlling the exciter current and the engine speed of the generator.
The need for synchronization arrives, particularly when two or more alternators are working together to supply the power to the load. This is because electrical loads are not constant and they vary with time and hence they necessitate the interconnection of two or more alternators operating in parallel to supply larger loads.
Synchronization matches various parameters of one alternator (or generator) to another alternator or to the bus bar. The process of synchronization is also called as paralleling of alternators.
Need of Paralleling of Generators
In most commercial power plants, several small units supply the power rather than single large unit. This is called as parallel operation of generators. The reasons for preferring this practice are enumerated below.
Reliability
Several small units are more reliable than single large unit. This is because, if one alternator is failed, other alternators are still active and hence the whole system will not be shutdown.
Continuity of Service
In case of periodic maintenance, break-down, or repairs of one alternator, it must be shutdown and removed from service. Since the other machines are operating in parallel, the interruption to supply the load is prevented.
Load Requirements
The load requirements in the central station changes continuously. During light-load periods only one or two generators are operated to supply the load demands. During peak-load demands, other alternators are connected in parallel to meet the demand.
High Efficiency
Generators run most efficiently when they are loaded at their rated values. Due to the operation of few generators at light-loads and more generators at high peak loads efficiently loads the generators.
Expanded Capacity
As the demand for electric power is increasing continuously, utility companies have been increasing the physical size of the generating plants by adding more alternators. So these alternators have to be connected in parallel with the existing generator equipment.
Conditions for Synchronization or Paralleling of Generators
There are certain requirements that must be met for successful paralleling of alternators. The following conditions must be met in order to synchronize a generator to the grid or with other generators.
Phase Sequence
The phase sequence of the three phases of the alternator which is being connected to the power system bus must be same as the phase sequence of the three phases of the bus bar (or electric grid). This problem comes mainly in the event of initial installation or after maintenance.
Voltage Magnitude
The RMS voltage of the incoming alternator should be same as the RMS voltage of the bus bar or electric grid. If the incoming alternator voltage is more than the bus bar voltage, there will be a high reactive power that flows from the generator into the grid.
If the incoming alternator voltage is lower than the bus bar voltage, generator absorbs the high reactive power from the bus bar.
Frequency
The frequency of the incoming generator must be equal to the frequency of the bus bar. Improper matching of frequency results high acceleration and deceleration in the prime mover that increases the transient torque.
Phase Angle
The phase angle between the incoming generator voltage and voltage of the bus bar should be zero. This can be observed by comparing the occurrence of zero crossing or peaks of the voltage waveforms.
Procedure for Connecting Alternators in Parallel
When the above stated methods are fulfilled, the alternators are said to be in synchronism. The actual process of synchronization or paralleling generators includes the following steps.
Connecting Alternators in Parallel
Consider that alternator-1 is supplying power to the bus bars at rated voltage and frequency.
Now, an incoming alternator-2 is to be connected in parallel with alternator-1 for the first time. By increasing the speed of the alternator, its frequency is varied and hence the speed is adjusted till it matches with bus bar frequency (or the frequency of alternator-1). Also by varying the field rheostat, the voltage of the alternator-2 is varied and hence it is adjusted till the voltage matches with bus bar voltage.
Synchronization of Generators
Often electrical generators are removed from the service and connected back to the power system during variations of the load, emergency outages, maintenance, etc.
Before reconnecting the generator to the system in each time, it must be synchronized with parameters of the power system network.
An improper synchronization can affect the healthy power system and results in electrical and mechanical transients that can damage the prime mover, generator, transformers and other power system components.
What is Synchronization of Generators?
The process of matching parameters such as voltage, frequency, phase angle, phase sequence and waveform of alternator (generator) or other source with a healthy or running power system is called synchronization.
Generator cannot deliver power to electric power system unless its voltage, frequency and other parameters are exactly matched with the network. Synchronization is accomplished by controlling the exciter current and the engine speed of the generator.
The need for synchronization arrives, particularly when two or more alternators are working together to supply the power to the load. This is because electrical loads are not constant and they vary with time and hence they necessitate the interconnection of two or more alternators operating in parallel to supply larger loads.
Synchronization matches various parameters of one alternator (or generator) to another alternator or to the bus bar. The process of synchronization is also called as paralleling of alternators.
Need of Paralleling of Generators
In most commercial power plants, several small units supply the power rather than single large unit. This is called as parallel operation of generators. The reasons for preferring this practice are enumerated below.
Reliability
Several small units are more reliable than single large unit. This is because, if one alternator is failed, other alternators are still active and hence the whole system will not be shutdown.
Continuity of Service
In case of periodic maintenance, break-down, or repairs of one alternator, it must be shutdown and removed from service. Since the other machines are operating in parallel, the interruption to supply the load is prevented.
Load Requirements
The load requirements in the central station changes continuously. During light-load periods only one or two generators are operated to supply the load demands. During peak-load demands, other alternators are connected in parallel to meet the demand.
High Efficiency
Generators run most efficiently when they are loaded at their rated values. Due to the operation of few generators at light-loads and more generators at high peak loads efficiently loads the generators.
Expanded Capacity
As the demand for electric power is increasing continuously, utility companies have been increasing the physical size of the generating plants by adding more alternators. So these alternators have to be connected in parallel with the existing generator equipment.
Conditions for Synchronization or Paralleling of Generators
There are certain requirements that must be met for successful paralleling of alternators. The following conditions must be met in order to synchronize a generator to the grid or with other generators.
Phase Sequence
The phase sequence of the three phases of the alternator which is being connected to the power system bus must be same as the phase sequence of the three phases of the bus bar (or electric grid). This problem comes mainly in the event of initial installation or after maintenance.
Voltage Magnitude
The RMS voltage of the incoming alternator should be same as the RMS voltage of the bus bar or electric grid. If the incoming alternator voltage is more than the bus bar voltage, there will be a high reactive power that flows from the generator into the grid.
If the incoming alternator voltage is lower than the bus bar voltage, generator absorbs the high reactive power from the bus bar.
Frequency
The frequency of the incoming generator must be equal to the frequency of the bus bar. Improper matching of frequency results high acceleration and deceleration in the prime mover that increases the transient torque.
Phase Angle
The phase angle between the incoming generator voltage and voltage of the bus bar should be zero. This can be observed by comparing the occurrence of zero crossing or peaks of the voltage waveforms.
Procedure for Connecting Alternators in Parallel
When the above stated methods are fulfilled, the alternators are said to be in synchronism. The actual process of synchronization or paralleling generators includes the following steps.
Connecting Alternators in Parallel
Consider that alternator-1 is supplying power to the bus bars at rated voltage and frequency.
Now, an incoming alternator-2 is to be connected in parallel with alternator-1 for the first time. By increasing the speed of the alternator, its frequency is varied and hence the speed is adjusted till it matches with bus bar frequency (or the frequency of alternator-1). Also by varying the field rheostat, the voltage of the alternator-2 is varied and hence it is adjusted till the voltage matches with bus bar voltage.
FoleysFollies · 51-55, F
FoleysFollies · 51-55, F
@Riverman lol thanks..immediately passed out 😂
FoleysFollies · 51-55, F
@Riverman lol thanks..immediately passed out 😂
Riverman · 56-60, M
@FoleysFollies Works for me too. 😂
wintersecret · 41-45, M
5thApprentice · 31-35, M
FoleysFollies · 51-55, F
@SW-User puff the magic dragon always used too work 😊
Picklebobble2 · 56-60, M