the substation components study

it has components and equipment used in the substation like feeders,circuit breakers,transformer parts etc..

1. STUDY OF SUBSTATION COMPONENTS UNDER THE GUIDENCE OF Mr. PAVAN KUMR BALA KRISHNA BY K.KRISHNVENI G.MANISHA M.MOUNIKA S.G.L. PRASANNA

2. SUBSTATION COMPONENTS A  substation  is a part of an electrical  generation ,  transmission , and  distribution  system. Between the generating station and consumer, electric power may flow through several substations at different voltage levels.

3. Transmission substation Distribution substation Converter substations Switching substation Classification by insulation Classification by structure CLASSIFICATION

4. MAIN COMPONENTS TRANSFORMER CIRCUIT BREAKER LIGHTING ARRESTER CURRENT TRANSFORMER

5. BUS BAR ISOLATOR POTENTIAL TRANSFORMER WAVE TRAP

6. INSULATOR EARTH SWITCH EARTHING SYSTEM CONTROL PANEL

7. CABLES CABLE PARTS TYPES OF CABLES TWISTED CABLES

8. TRANSFORMER Power transformers are used in   transmission  network of higher voltages for step-up and step down application (400 kV, 200 kV, 110 kV, 66 kV, 33kV) and are generally rated above 200MVA. Distribution transformers are used for lower voltage distribution networks as a means to end user connectivity. (11kV, 6.6 kV, 3.3 kV, 440V, 230V) and are generally rated less than 200 MVA.

9. PARTS OF TRANSFORMER Main tank Primary winding Secondary winding Buchholz relay Oil level indicator Breather Radiator L T & HT bushes Tap changer Air release plug

10. Buchholz relays Buchholz relays are used in most oil insulated electric transformers where there is an expansion tank. Buchholz relays are particularly efficient in detecting and capturing gases that may form inside the transformers and for instant system shut down in case of a serious defect. CONSERVATOR The conservator provides space for the expansion of oil . CONSERVATOR BUCHHOLZ RELAY

11. BREATHER The breather filled with silica gels are provided to separate moisture from the aspirated air. The silica gel turns blue when it becomes saturated with moisture after which it needs to be replaced. AIR RELEASE PLUGS These air releasing plugs are made from very excellent quality raw material which ensure hassle free work performance. These plugs finds its applications in various industrial sectors. We are able to customized these plugs as per customer requirement with market competitive rates BREATHER AIR RELEASE PLUGS

12. TERMINAL BOX A terminal box is designed to enable the electrical connection of the elements within a transformer to the external elements in an airtight and reliable manner that ensures years of trouble-free operation . COOLING FANS They are used for cooling of the transformer when there is a temperature raise in the transformer. TERMINAL BOX COOLING FANS

13. RADIATORS The  radiator of transformer accelerates the cooling rate of transformer. Thus, it plays a vital role in increasing loading capacity of an  electrical transformer . This is basic function of radiator of an electrical power. TRANSFORMER RATING RADIATORS

14. TAP CHANGER  A tap changer is a connection point selection mechanism along a power T/F winding that allows a variable number of turns to be selected in discrete steps. A T/F with a variable turns ratio is produced, enabling stepped voltage  regulation of the output. The tap selection may be made via an automatic or manual  tap . BHUSHINGS OF T/F The oil impregnated paper insulated bushings arc used to connect over head lines to T/F. These are mounted on t/f in vertical or inclined position at a maximum inclnation of 30° from the verticaL . TAP CHANGER BUSHINGS OF T/F

15. BUS BARS a bus bar is a thick strip of copper or aluminium that conducts electricity. Bus bars are used to carry very large currents, or to distribute current to multiple devices within switchgear or equipment.

16. CIRCUIT BREAKER It designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and discontinue the electric flow .

17. BULK OIL CB BULK OIL CB It uses a large quantity of oil The oil serves two purposes. Firstly ,it extinguishes the arc during opening of contacts. Secondly ,it insulates the current conduting parts from one anthor and from the earthed tank . AIR BLAST CB The CB in which high pressure air blast is used for extinguishing the arc. The arcing products are completely removed by the blast whereas the oil deteriorates with successive operations. The expense of regular oil replacement is avoided AIR BLAST

18. MINIMUM OIL CB These types of circuit breakers utilize oil as the interrupting media. However, unlike bulk oil circuit breaker, a minimum oil circuit breaker places the interrupting unit in insulating chamber at live potential. The insulating oil is available only in interrupting chamber. The features of designing  MOCB  is to reduce requirement of oil, and hence these breaker are called minimum oil circuit breaker. CROSS BLAST CB The CB in which the air blast is directed right angles to the arc path . The splitters serve to increase the arc length of the arc and baffles give improved cooling resulting in extinguished arc. MINIMUM OIL CROSS BLAST

19. AUXIAL BLAST CB The circuit breaker in which the air blast is directed long the arc path When the fault occurs the arc is extinguished and current flow is interrupted. SF6 CB The circuit breaker in which sulphur dioxide (SF6)gas is used for arc extinction. Due to superior arc quenching property of SF6 ,such circuit breakers have short arcing time. AUXIAL BLAST SF 6

20. Actuator lever - used to manually trip and reset the circuit breaker. Actuator mechanism - forces the contacts together or apart Contacts - Allow current when touching and break the current when moved apart Terminals Bimetallic strip. Calibration screw - allows the manufacturer to precisely adjust the trip current of the device after assembly. Solenoid Arc divider/extinguisher CIRCUIT BREAKER

21. ISOLATOR It is a disconnection switch and to be operated on no load. It is used to make sure that an electrical circuit can be completely de-energized for service or maintenance.   It provide electrical isolation of the equipment .

22. CURRENT TRANSFORMER CT is a type of instrument transformer that is used in power system for measurement, detection, protection of the system. Current transformers are used extensively for measuring current and monitoring the operation of the power grid.

23. POTENTIAL TRANSFORMER Potential transformers are instrument transformers. They have a large number of primary turns and a few number of secondary turns. It converts voltages from high to low. It will take the thousands of volts behind power transmission systems and step the voltage down to something that meters can handle. 

24. LIGHTING ARRESTER It discharge the over voltage surges to earth and protect the equipment insulation from switching surges and lightning surges. It located at the starting of the substation as seen from incoming transmission lines and is the first equipment of the substation

25. INSULATOR An insulator, also called a dielectric, is a material that resists the flow of electric current. Insulators are used in electrical equipment to support and separate electrical conductors without allowing current through themselves. 

26. PIN TYPE SUSPENSION TYPE PIN TYPE Pin type insulators are used for transmission and distribution of electric power at voltages up to 33 kV. Beyond operating voltage of 33 kV, the pin type insulators become too bulky and hence uneconomical. SUSPENISION TYPE   For high voltages (>33 kV), we use suspension type insulators. Each unit or disc is designed for low voltage, say 11 kV. For instance, if the working voltage is 66 kV, then six discs in series will be provided on the string. STRAIN TYPE When there is a dead end of the line or there is corner or sharp curve, the line is subjected to greater tension. In order to relieve the line of excessive tension, strain insulators are used. For low voltage lines (< 11 kV), shackle insulators are used as strain insulators.  STRAIN TYPE

27. STRAIN TYPE SHACKLE TYPE SHACKLE TYPE In early days, the shackle insulators were used as strain insulators. But now a day, they are frequently used for low voltage distribution lines. Such insulators can be used either in a horizontal position or in a vertical position. They can be directly fixed to the pole with a bolt or to the cross arm. STRAIN TYPE When there is a dead end of the line or there is corner or sharp curve, the line is subjected to greater tension. In order to relieve the line of excessive tension, strain insulators are used. For low voltage lines (< 11 kV), shackle insulators are used as strain insulators. However, for high voltage transmission lines, strain insulator consists of an assembly of suspension insulators as shown in Figure. The discs of strain insulators are used in the vertical plane. When the tension in lines is exceedingly high, at long river spans, two or more strings are used in parallel.

28. WAVE TRAP It trap the high frequency communication signals sent on the line from the remote substation and diverting them to the telecom/ teleprotection panel in the substation control room . The Line trap offers high impedance to the high frequency communication signals thus obstructs the flow of these signals in to the substation bus bars. The signals are primarily teleprotection signals and in addition, voice and data communication signals. 

29. EARTH SWITCH Earth Switch is used to discharge the voltage on the circuit to the earth for safety. Earth switch is mounted on the frame of the isolators. Earth Switch is located for each incomer transmission line  and each side of the bus-bar section

30. EARTHING SYSTEM Station Earthing System includes Earth Mat and Earth electrodes placed below ground level Function earthing system is to provide low resistance earthing for Discharging currents from the surge arresters, overhead shielding, earthing switches For equipment body earthing For safe touch potential and step potential in substation.

31. METERING, CONTROL AND RELAY PANELS To house various measuring Instruments, control Instruments, Protective relays. They are located in air-conditioned building. Control Cables are laid between Switchyard equipment and these panels.

32. RELAYS TYPES Electromagnetic relays   These are those relays which are operated by electromagnetic action. Modern  electrical protection relays  are mainly micro processor based, but still electromagnetic relay holds its place. It will take much longer time to be replaced the all electromagnetic relays by micro processor based static relays. Induction relay This relay in nothing but one version of induction disc relay. Induction cup relay work in same principle of induction disc relay. The basis construction of this relay is just like four poles or eight pole  induction motor . The number of poles in the  protective relay  depends upon the number of winding to be accommodated . 

33. CABLES STRUCTURE & CONSTRUCTION

34. THREE CORE CABLES TYPES

35. TYPES OF FEEDERS