Sîstema Elektrîk a Otobüsü û Pêşgotina Elektrîk a Stasyonê
Zêde wateyên cîhanî û rêzikî sîstemê bus êlektrîk hene, lê bihêvîna yek sîstem taybetand bêrpa dike ku bihêvîna gerêzê, pozîsyona subway di sîstemê nirxanên êlektrîk de, herêmîyek bihêviyê yên di sîstem da bikaranîn û maliyeyek bihêvîn.
The Main Criterias to be Considered During Selection of one Particular Bus – Bar Arrangement Scheme
Sadekirina sîstemê.
Bakarîya werdêkariya pergalên din.
Kamkirina çêteweyê di dema werdêkarî de.
Provizyonê ya dawî bi sererastkirina dermandiyan.
Helmkirina sîstemê bus bar û dest pêkirina yek sîstem taybetand ku ji sîstemê vegera herêmîya zêde bigire.
Çend sîstemên bus barên çawn bikaranîn hene, wan di navbera jêr bibînin-
Single Bus System
Single Bus System herêmîya sade û nîşana ye. Di vê sîstem de hemû feeders û transformer bay bi yek bus tenê têne guherand.
Advantages of Single Bus System
Vê sadeye ji bo dizaynê ye.
Vê sîstemê ekonomik e.
Vê sîstemê bakarî ye.
Disadvantages of Single Bus System
Yek xebitiya mezin ê vê sîstemê ye ku, werdêkariya pergalên her bay bi bêgara feedera an transformer bi yek bay niha nebe.
Indoor 11 KV switch boards piçûka sîstemê bus bar single ne.
Single Bus System with Bus Sectionalizer
Hemin avameyek dest pê kirin hene yek bus bar bi circuit breaker sectionalized be. Heke bihêve yek incoming û sources incoming û outgoing feeders li ser sections ve berhevd be, interruption of a system can be reduced to a reasonable extent.
Advantages of Single Bus System with Bus Sectionalizer
Heke her sourcekan ji sîstemê derbas bike, heta hemû loads bi switching on the sectional circuit breaker an bus coupler breaker fed be. Heke yek section li sîstemê bus bar werdêkarî be, part load of the substation can be fed by energizing the other section of the bus bar.
Disadvantages of Single Bus System with Bus Sectionalizer
Weke sîstemê bus bar single, werdêkariya pergalên her bay bi bêgara feedera an transformer bi yek bay niha nebe.
Use of isolator for bus sectionalizing does not fulfill the purpose. The isolators have to be operated ‘off circuit’ and which is not possible without total interruption of bus-bar. So investment for bus-coupler breaker is required.
Double Bus System
Di sîstemê bus bar double de, du bus bar identik hatine bikar bînin, heke any outgoing or incoming feeder can be taken from any of the bus.
Actually every feeder is connected to both of the buses in parallel through individual isolator as shown in the figure.
By closing any of the isolators, one can put the feeder to the associated bus. Both of the buses are energized, and total feeders are divided into two groups, one group is fed from one bus and other from other buses. But any feeder at any time can be transferred from one bus to other. There is one bus coupler breaker which should be kept close during bus transfer operation. For transfer operation, one should first close the bus coupler circuit breaker then close the isolator associated with the bus to where the feeder would be transferred and then open the isolator associated with the bus from where the feeder is transferred. Lastly, after this transfer operation, he or she should open the bus coupler breaker.
Advantages of Double Bus System
Double Bus Bar Arrangement increases the flexibility of system.
Disadvantages of Double Bus System
The arrangement does not permit breaker maintenance without interruption.
Double Breaker Bus System
In double breaker bus bar system two identical bus bars are used in such a way that any outgoing or incoming feeder can be taken from any of the bus similar to double bus bar system. The only difference is that here every feeder is connected to both of the buses in parallel through individual breaker instead only isolator as shown in the figure. By closing any of the breakers and its associated isolators one can put the feeder to respective bus. Both of the buses are energized, and total feeders are divided into two groups, one group is fed from one bus and other from other buses similar to the previous case. But any feeder at any time can be transferred from one bus to other. There is no need for bus coupler as because the operation is done by breakers instead of isolators. For transfer operation, one should first close the isolators and then the breaker associated with the bus to where the feeder would be transferred, and then he or she opens the breaker and then isolators associated with the bus from where the feeder is transferred.
One and A Half Breaker Bus System
This is an improvement on the double breaker scheme to effect saving in the number of circuit breakers. For every two circuits, only one spare breaker is provided. The protection is however complicated since it must associate the central breaker with the feeder whose own breaker is taken out for maintenance. For the reasons given under double breaker scheme and because of the prohibitory costs of equipment, even this scheme is not much popular. As shown in the figure that it is a simple design, two feeders are fed from two different buses through their associated breakers, and these two feeders are coupled by a third breaker which is called tiebreaker. Normally all the three breakers are closed, and power is fed to both the circuits from two buses which are operated in parallel. The tiebreaker acts as a coupler for the two feeder circuits. During the failure of any feeder breaker, the power is fed through the breaker of the second feeder and tiebreaker, therefore each feeder breaker has to be rated to feed both the feeders, coupled by the tiebreaker.
Advantages of One and A Half Breaker Bus System
During any fault on any one of the buses, that faulty bus will be cleared instantly without interrupting any feeders in the system since all feeders will continue to feed from other healthy bus.
Disadvantages of One and a Half Breaker Bus System
This scheme is much expensive due to investment for third breaker.
Main and Transfer Bus System
