In this scheme, when the generator was in synchronism with the system, one lamp would be dark, but the two with the swapped connections would be of equal brightness. Conditions[ edit ] There are five conditions that must be met before the synchronization process takes place.
Thus there is a need of autosynchroniser in a power station or in an industrial establishment where generators are employed. If Microprocessor based alternator synchronisation machine is slightly out of phase it will pull into step with the others but, if the phase difference is large, there will be heavy cross-currents which can cause voltage fluctuations and, in extreme cases, damage to the machines.
At that instant, the circuit breaker connecting the generator to the system may be closed and the generator will then stay in synchronism with the system. Also existing methods of synchronization are mentioned. Synchro check relays are also applied in Microprocessor based alternator synchronisation where several sources of supply may be connected and where it is important that out-of-step sources are not accidentally paralleled.
When the voltage at the generator is opposite to the system voltage either ahead or behind in phasethe lamps will be bright.
Once synchronized properly, the two alternators continues to run in synchronism. In the dark lamp method the lamps are connected across the alternator and busbar terminal. As the generator speed changes, the lights will flicker at the beat frequency proportional to the difference between generator frequency and system frequency.
The connection of an incoming alternator to system bus, ie; synchronization requires fulfillment of the condition like the same phase sequence equality of voltages and frequency between the incoming machine and frequency between the in coming machine and busbar. In addition, the auto synchronizer has been designed so that the alternator is started with in minimum voltage and minimum frequency conditions.
It means that the switch must be closed at the instant the two voltages are in correct phase. The voltage magnitude must be the same as the system voltage. Under emergency condition such as lowering of frequency or synchronizing of large machines a very fast action is needed, which may not be possible for a human operator.
Synchronous operation[ edit ] When the generator is synchronized, the frequency of the system will change depending on load and the average characteristics of all the generating units connected to the grid.
When the two systems are synchronized, the pointer on the synchrosope is stationary and points straight up. Synchronous speeds[ edit ] Synchronous speeds for synchronous motors and alternators depend on the number of poles on the machine and the frequency of the supply.
During installation of a generator, careful checks are made to ensure the generator terminals and all control wiring is correct so that the order of phases phase sequence matches the system. Synchronizing relays[ edit ] Synchronizing relays allow unattended synchronization of a machine with a system.
The field of the generator is energized and the voltage at the terminals of the generator is observed and compared with the system.
To minimize the transient current when the generator circuit breaker is closed, usual practice is to initiate the close as the needle slowly approaches the in-phase point. Protective devices on the generator will operate to disconnect it automatically. If the phase sequence is different, the lamps will brighten in a cyclic manner correct phase sequence is indicated by simultaneous darkening brightening of lamps.
A synchronizing relay is useful to remove human reaction time from the process, or when a human is not available such as at a remote controlled generating plant.
In order to order to overcome the 9 technical drawbacks of the conventional synchronization methods we can introduce a microprocessor based system. However, a lamp burnout could give a false-positive for successful synchronization. The relationship between the supply frequency, f, the number of poles, p, and the synchronous speed speed of rotating fieldns is given by: Synchroscopes or lamps are sometimes installed as a supplement to automatic relays, for possible manual use or for monitoring the generating unit.
Today these are digital microprocessor instruments, but in the past electromechanical relay systems were applied. Condition 1 can be checked with the help of voltmeter, frequency is adjusted by varying the prime mover speed.
The scheme introduced here is for the complete automation of synchronization i. When the voltage at the generator matches the system voltage, the lights will be dark.
Synchroscope Another manual method of synchronization relies on observing an instrument called a "synchroscope", which displays the relative frequencies of system and generator.
Synchronizing on "dark" lamps was preferred over "bright" lamps because it was easier to discern the minimum brightness. The speed of the incoming machine must be same such that the frequency is equal to the busbar frequency.
An error of a few electrical degrees between system and generator will result in a momentary inrush and abrupt speed change of the generator.Microprocessor Based Alternator Synchronisation,Ask Latest information,Abstract,Report,Presentation (pdf,doc,ppt),Microprocessor Based Alternator Synchronisation technology discussion,Microprocessor Based Alternator Synchronisation paper presentation details.
In an alternating current electric power system, synchronization is the process of matching the speed and frequency of a generator or other source to a running network. An AC generator cannot deliver power to an electrical grid unless it is running at the same frequency as the network.
Electrical Engineering. Preparation of Electrical Single line diagram by using SPEL software. Selection of HV/LV Switchgear, Motor Control Centers.
Microprocessor Based Alternator Synchronisation; Surge Current Protection Using Superconductors; Magnetic Levitation. Fundamentals and Advancements in Generator Synchronizing Systems Michael J. Thompson Schweitzer Engineering Laboratories, Inc. Fundamentals and Advancements in Generator Synchronizing Systems microprocessor-based devices and selected in logic.
Remote. This is the good Electrical project report on Microprocessor Based Automatic Alternator Synchronization and the scheme introduced here is for the complete automation of synchronization i.e. the adjustment of magnitude of voltage and frequency of incoming alternator.
Download Citation on ResearchGate | Microprocessor based alternator synchroniser | The manual method of synchronisation demands a skilled operator and the method is suitable for no load operation.Download