Explain synchronisation and parallel operation, Electrical Engineering

Assignment Help:

Explain Synchronisation and Parallel Operation

Generation, transmission and distribution of electric power have to be conducted in an efficient and reliable way at a reasonable cost with the least amount of interruptions. Consequently, in a large power system many synchronous generators are connected in parallel to a common line known as an infinite bus of fixed voltage and frequency, and pre-determined phase sequence. A number of safety requirements need to be satisfied prior to connecting a generator to the infinite bus (this is called a synchronising procedure):

2448_Explain Synchronisation and Parallel Operation.png

(1) The operating frequency,

(2) The line voltage and

(3) The phase sequence must all be the same as those for an infinite bus.

To meet an increased load demand, let us, for instance, bring a second generator into service as shown in Figure. The necessary synchronisation procedure consists of the following major steps. The speed of the incoming generator is adjusted to obtain the frequency of the induced voltage equal to that of the infinite bus. Now that the frequency match is achieved the field current can be raised to a level at which the induced voltage of the second generator is identical to the bus voltage. In order to verify the phase sequence, three lamps are connected asymmetrically as illustrated in the figure. When the phase sequence is correct, the lamp LI will be dark, while the other two lamps will glow brightly. If the phase sequence is not proper, all the lamps will glow or become dark simultaneously. When all the above conditions are met, the second generator can be safely connected to the infinite bus by closing the appropriate circuit breaker.

In addition to the lamps to check the conditions for synchronism, an electronic device (often computer controlled) called a synchroscope is also used to perform a precise switching when the above criteria are fulfilled. It provides the information on the incoming generator as to whether it is running at a lower or higher speed. At a proper speed and a correct phase sequence, the synchroscope indicates zero when the synchronising switch must be closed to connect the second generator on line. At this moment, it is neither receiving nor delivering any power. This is referred to as the floating stage of the generator. If we now increase the field current, the second generator will produce reactive power and help improve voltage regulation. Else, if an attempt is made to increase the rotor speed, the torque developed will increase and the second generator will begin to supply active power to the load.


Related Discussions:- Explain synchronisation and parallel operation

Determine the bounds on the carrier frequency, Suppose that a video signal,...

Suppose that a video signal, having W = 5 MHz, is transmitted via FM with f = 20 MHz. For 1/100 ≤ B/fc ≤ 1/10, determine the bounds on the carrier frequency. Use WFM ∼ = 2( ω + 2W

Program analysis , Program Analysis We have to find the greater of two...

Program Analysis We have to find the greater of two given  number. We  can store the given  numbers  in two  different  registers ( suppose register A and B). Then we will com

What do you understand by common control, Q. What do you understand by comm...

Q. What do you understand by common control? In some switching systems, control subsystem may be an integral part of switching network itself. Such system iscalled direct contr

Hi, Two projects using the principle of functional independence, increases ...

Two projects using the principle of functional independence, increases system accuracy?

Give some applications of constantan, Give some applications of constantan....

Give some applications of constantan. Constantan is an alloy of nickel and copper. It is used in thermocouples, motor starters and precision resistors.

Electric scooter, Hi there i need help with design battery charger for elec...

Hi there i need help with design battery charger for electric scooter 24v battery. i have to design sechmatic diagram and PCB for it. using Altuim design software many thanks 006

Express the storedmagnetic energ, A relay is essentially an electromechanic...

A relay is essentially an electromechanical switch that opens and closes electrical contacts. A simplified relay is represented in Figure. It is required to keep the fenomagnetic p

Explain einstein relation, Explain Einstein relation. Einstein relation...

Explain Einstein relation. Einstein relation: There exists a significant relation between the diffusion constant and the mobility. It is termed as the Einstein relation and

Explain about direct-current machines, Q. Explain about Direct-current mach...

Q. Explain about Direct-current machines? Generally speaking, conventional dc generators are becoming obsolete and increasingly often are being replaced by solid-state rectifie

Illustrate transformer coupling, Q. Illustrate Transformer coupling? In...

Q. Illustrate Transformer coupling? In this method the primary winding of the transformer acts as a collector load and the secondary winding transfers the a.c. output signal di

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd