Electrical Substations

-

     Electrical Substations

An electrical substation forms an integral part of the power system. It is placed at the both ends of the long distant transmission line...

but why??!! Of-course to transform voltage!

 A substation at the beginning End or say generation side normally used to boost up the voltage to higher magnitude suitable for transmitting the generated power to long distant load with minimum losses.( Uses a step up transformer )!! Yes the other type is at the other end of the long distant transmission line nearer to load centre... here the high voltage is stepped down to a relevant magnitude which may be used for distribution purpose or another voltage level transmission for near by substations.

                   The heart of a substation is nothing but our transformer, depending upon the purpose transformer can be step up or step down!! Now we are considering a load end substation as an example. Here our hero is step down transformer 😎!! A substation has a fenced area called substation yard and our hero called transformer lies in it along with the protection devices, switching equipments, metering equipments more over a "control unit" simply a control room with all its controls😉.
Control room includes panel boards of every units in the yard and these panel boards is simply filled with controlling keys,switches,ammeter,voltmeter, energy meters,indication lights, semaphores, MW meters ,MVAR meters etc... Also there is relays etc... All these are for evaluating and monitoring the performance of the whole station!!

                                       
Above is single line diagram of a typical substation.

The incoming portion from the tower called as feeder( high voltage) the conductors from the tower is first connected to the lighting arrester(LA). Then it travels to Capacitive voltage transformer (CVT) after that it meets the isolator and current transformer (CT) finally to circuit breaker (CB). All equipments and structural unit will have adequate level of insulations since they are dealing with high voltages!!
Lighting Arrester

Isolators

Circuit breaker

CVT & CT 

The output of circuit breaker or say second terminal of the CB is connected to the busbars. The busbars contains parallel connected feeders and transformers ...!
                 
       Transformer

 As said above the transformer step downs voltage to a lower level according to need( design and rating of transformer is decided) of-course the transformers also have CT, Isolator,LA, circuit breakers and relays all these co-ordinate to protecting and operation of the transformer. It employs differential protection scheme😉 the secondary side or output of transformer is again connected to low voltage (w.r.t. primary) busbar and again the power is now ready for its further journey out side the substation!!!!!!😉😉😉


Comments

Post a Comment

Popular posts from this blog

Differential Protection Scheme (Transformer)

-
Image
Hey friends! you are familiar with the power system equipment which we discussed earlier.! Now it's time to protect it to total safety. As soldiers protect our country from enemies likewise our system should be protected from fault. The line of control is decided by fixing the current transformers on the right place. So our boundaries is decided by their location. Here in a substation, we have many equipments such as transmission lines, bus-bar, transformers, etc in the system which need atmost care. Starting from the bulkiest, transformers are having different level of protections such as phase to phase and phase to ground. In other words differential protection and earth-fault protection. Over-current protection is also implemented in it. Let's talk about the differential type of protection for transformers. It's quite simple to explain the theory but some complicated while coming into the calculation. The term itself gives a brief idea about the
Read more

Capacitor banks and reactors

-
Image
Capacitor banks and Reactors We have already discussed the significance of reactive power in a power system, As we know the availability of reactive power depends on the excitation of the alternators.This reactive power can be provided by the generators themselves, through the adjustment of generator excitation, but it is often cheaper to provide it through capacitors, hence capacitors are often placed near inductive loads to inject reactive power.the so called capacitors are mainly of two, static condensers and synchronous condensers. The synchronous condensers have a variable value of VAR which can be varied by the excitation of the synchronous motor and the static capacitors have a fixed value of VAR.                                       The capacitor bank simply means that a group of  individual capacitors connected in  parallel and series accordingly to the design of the capacitor bank and together have a value in KVAR or MVAR. Capacitor Connection  A reactor is connected i
Read more