ELECTRICAL INSTALLATIONS PPT (1).pptx

Electric switch gear type description.

1. Unit-5 Electrical Installations Presented by Mr. K. Shankar

2. Syllabus Components of LT Switchgear Types of Wires & Cables Concept of Earthing Types of Batteries & Characteristics Energy consumption calculations Power factor improvement methods Battery backup

3. Switch-Gear Switchgear is responsible for connecting and disconnecting the electric power supplies from other systems. Switchgear is a general term used to covers the switching device and its various combinations with some associated control, measuring all parameter, protective and regulating equipment, together with accessories, enclosures and supporting structures

4. Classification of Switchgear Depending upon the voltage to be handled, switchgear can be classified into 1. Outdoor type Switchgear 2. Indoor type Switchgear Outdoor type switchgear: For voltages beyond 66kV Space required for the accessories ( circuit breakers, transformers, switches) is not economical. Indoor type switchgear: For voltages below 66kV All parts are enclosed in metal casing.

5. Classification of Switchgear Depending upon the voltage level, Switchgear can be classified into Low voltage switchgear (up to 1000V AC & 1500V DC) Medium voltage switchgear ( 3.3 kV to 33 kV ) High voltage switchgear ( Above 36 kV )

6. Components of LT Switch Gear SFU (Switch Fuse Unit) MCB (Miniature Circuit Breaker) MCCB (Moulded Case Circuit Breaker) ELCB ( Earth Leakage Circuit Breaker)

7. SFU (Switch Fuse Unit) The switch fuse units are used for distributing power and protecting electrical devices and cables from damage due to fluctuations. This fuse unit is housed in an enclosure made using quality CR steel sheet Salient Features: Pre-treated or powder coated finish For cable connections, knock outs are provided at bottom, top and rear side High conductivity due to nickel or silver plated contact Durable and rewirable . Application: used in industrial, residential and commercial buildings for electrical fittings

8. Fuses Fuse is an electrical safety device that operates to provide over current protection of an electrical circuit. Its essential component is a metal wire or strip that melts when too much current flows through it, therby stopping or interrupting the current. Types of fuses:- Rewirable or Kit-Kat type fuse unit Cartridge type fuse unit HRC type fuse unit Semiconductor type fuse unit

9. Rewirable or Kit-Kat type fuse unit The fuse base is generally made up of porcelain Fuse element is made up of tinned copper, aluminium etc When the fuse is blown due to over current, we can easily remove the fuse carrier and replace the fuse wire. They are most commonly used in house wiring, small industries and other small current applications

10. Cartridge type fuse unit A cartridge fuse including a tubular insulating body Integrally formed ferrule terminals secured over the respective ends of the insulating body. A fusible strip extending within the insulating body electrically interconnecting the ferrule terminals. They are available up to 600A and 600V AC and widely used in industries, commercial as well as home distribution panels.

11. HRC type fuse unit HRC-High Rupturing Capacity HRC Fuse consists of highly heat resistant material (such as ceramic) body having metal-end caps, which is welded by silver current carrying element. The fuse body internal space is completely packed with a filling powder which may be plaster of Paris, quartz, chalk, marble, dust and cooling mediums etc. The heat produced under abnormal condition vaporizes the silver melted element. Chemical reaction taking place between silver vapour and filling powder results in high resistance substance, which helps in quenching the arc in fuse HRC fuses are also available in a capacity of 16000A to 30000A at 400V HRC Fuses are also used for protection on low voltage distribution systems against overload and short circuit conditions

12. Semiconductor type fuse unit A semiconductor fuse is simply a very fast acting conventional fuse, designed to prevent damage to a semiconductor device It is usually used with larger semiconductor devices rated to switch 100A or more (SCRs, IGBTs, Power transistors, etc.) The I 2 t of the semiconductor fuse is less than the I 2 t of the semiconductor device and thus the fuse gets blown off before the device fails.

13. MCB MCB – Miniature circuit breaker. It automatically switches OFF electrical circuit during any abnormal condition in the electrical network such as overload & Short circuit conditions The MCB is an electromechanical device which guards the electric wires & electrical load from over current so as to avoid any kind of fire or electrical hazards.

14. Working of MCB Whenever continuous over current flows through MCB, the bimetallic strip is heated and deflects by bending. This deflection of bimetallic strip releases a mechanical latch. But during short circuit condition, the current rises suddenly, causing electromechanical displacement of plunger associated with a tripping coil or solenoid The plunger strikes the trip lever causing immediate release of latch mechanism consequently open the circuit breaker contacts. To restart the flow of current the MCB must be manually turned ON.

15. MCCB MCCB- moulded case circuit breaker It is a protecting device which protects the circuit form overloading, short circuit faults and for switching the circuits. It is mainly used in a place where adjustable tripping requires. the current rating of MCCB is up to 2500A. It is mainly used for high current applications. The MCCB are used for high energy applications. MCCB can be used for protection of generator protection and main electric feeder distribution.

16. ELCB (Voltage operated ELCB) ELCB- Earth Leakage Circuit breaker ELCB is basically an electrical wiring device that disconnects the circuit whenever there is leakage of current flow through the human body or the current is not balanced between the phase conductor. It is the safest device to detect and trip against electrical leakage currents, thus ensure protection against electric shock caused by direct contacts.

17. RCCB (Current operated ELCB) RCCB – Residual current circuit breaker. The polarity of the phase winding and neutral winding on the core is so chosen that in normal condition MMF of one winding opposes that of other. Under fault condition there is difference in to MMF so a resultant flux exists and trip coil is energized. Trip coil further isolated the supply to the load.

18. Difference between wire and cable Wire and cable are two terms that are used in electrical and communication fields. A wire is a single conductor strand or a group of conductor strands(copper or aluminium) while cable is two or more insulated wires wrapped in one jacket. Multiple conductors that have no insulation around would be classified as a single conductor.

19. Types of wires Wires can be classified into four types: Single strand wires Multi strand wires ACSR AAAC

20. Single strand wires Single strand wire also uses THHN (thermoplastic high heat resistant nylon coated) wire, though there are other variants. Each wire is separate and multiple wires can be drawn together through a pipe easily. Single strand wires are the most popular choice for layouts that use pipes to contain wires.

21. Multi strand wires Multi strand wiring is more flexible and less susceptible to cracking and metal fatigue than single stranded conductors. This makes it the preferable solution for wiring that will need to bend without experiencing metal fatigue. The increased surface area of multi stranded conductors decreases the amount of resistance that currents or signal passing through the wire will encounter.

22. ACSR Aluminium conductor steel reinforced ACSR is a type of high capacity, high strength stranded conductor typically used in overhead power lines. The outer strands are high purity aluminium, chosen for its good conductivity, low weight and low cost. The center strand is steel for additional strength to help support the weight of the conductor.

23. AAAC All aluminium alloy conductors Concentric lay stranded aluminium alloy conductors(AAAC) are made out of high strength aluminium-magnesium-silicon alloy. These conductors are designed to get better strength to weight ration and offer improved electrical properties, when compared with ACSR

24. Types of Cables According to the type of insulation, cables are classified as: VIR insulated cable CTS/TRS cable PVC cables Lead Sheathed cables

25. V I R cables (Vulcanized Indian Rubber) It consists of a copper conductor covered with a insulation layer of vulcanized Indian rubber (VIR). A cotton tape covering is provided over this insulation layer to protect the wire from moisture and to provide mechanical strength to the wire. Used for low or medium voltage Used for indoor wiring

26. CTS/TRS Wires Cab type sheathed (CTS) or TRS (Tough Rubber Sheathed) wires consists of vulcanized rubber insulated conductor. This insulation layer is covered by a layer made of tough rubber (or) tough rubber sheathed covering. This covering is very hard and protects the wire from moisture and provides mechanical strength. Used for some outdoor application 250-440V

27. PVC cables (Polyvinyl Chloride) These wires consists of a conductor over which an insulation layer made up of polyvinyl chloride is provided These wires cannot resist much heat and they have relatively low melting points, so they aren’t used in hot places and also these wires are not used with heating appliances. PVC wires are available in almost all colours. These are available in 250/440V grades

28. Lead Sheathed cables These wires consists of vulcanized Indian rubber insulated conductor over which Lead sheath is provided which gives mechanical strength to wire & also protects from moisture. As lead is conductor of electricity, the lead covering is provided with earth wire. These are available in 240/415V grade

29. Earthing The process of transferring the immediate discharge of the electrical charges directly to the earth by the help of low resistance wire is known as the electrical earthing . Thus earthing protects the operating personnel and some times the system and equipment from damage.

30. Effects of shock Let go current:- the maximum value of electric current through the body of a person at which that person can release himself or herself. This ranges between 10-20 mA . Under dry conditions, the resistance offered by the human body may be as high as 100,000 ohms. Wet or broken, skin may drop the body’s resistance to 1000 ohms.

31. Types of electrical earthing On the basis of type of installation earthing can be classified into following types Plate earthing Pipe earthing Rod earthing Strip earthing

32. Calculation of Energy Consumption Device Wattage (watts) x Hours Used Per Day = Watt-hours ( Wh ) per Day Device Usage ( Wh ) / 1000 ( Wh /kWh) = Device Usage in kWh Daily Usage (kWh) x 30 (Days) = Approximate Monthly Usage (kWh/Month) Monthly Usage (kWh) x Electric Rate (Rs./kWh) = Approximate Cost per Month A 125-watt television used three hours per day 125 watts x 3 hours = 375 Wh /Day A television using 375 Wh of electricity per day 375 / 100 = 0.375 kWh A television using 0.375 kWh of electricity per day 0.375 kWh x 30 Days = 11.25 kWh/Month A television using 11.25 kWh/Month with an electric rate of Rs. 2.60/kWh 11.25 kWh x Rs. 2.60 = Rs.29.25/Month

33. Methods for Power Factor Improvement Static Capacitor Synchronous Condenser Phase Advancer

34. Static Capacitor Inductive load are taking lagging current which decreases the system power factor. Capacitors provide leading current which neutralize the lagging inductive component of load current.

35. Static Capacitor Advantages: Losses are low in static capacitors Low maintenance Do not require a foundation for installation Light weight so easy to install Disadvantages: Age of capacitor bank is less (8-10 years) If the rated voltage increases then it causes damage Once capacitor spoiled then repairing is costly

36. Synchronous Condenser When a synchronous motor operates at No-load and over excited then its called a synchronous condenser. It provides leading current like a capacitor by over exciting the synchronous motor It draws leading current and eliminates the reactive component when synchronous condenser connected in parallel to the supply. These are used to improve the power factor in large industries.

37. Synchronous Condenser Advantages: Long life (almost 25 years) High reliability Requires low maintenance Faults can be removed easily Disadvantages: Produces noise It is expensive

38. Phase advancer It is a simple ac exciter. It is used to improve the power factor of induction motor in industries. Advantage: - The phase advancer can be easily used. Disadvantage: It is not economical for motors below 200HP. Supply Motor Phase Advancer

39. Phase advancer Advantage: - The phase advancer can be easily used. Disadvantage: It is not economical for motors below 200HP.

40. Types of Batteries Battery is a collection of one or more cells. Which converts chemical energy into electrical energy. There are 3 main components: - Anode, + Cathode & Electrolyte

41. Primary Cells These batteries cannot be recharged once depleted. These are made up of electrochemical cells. These batteries have specific energy. Applications: Wrist watches Remote controls children toys Portable entertainment devices Flashlights etc.

42. Secondary Cells These are rechargeable batteries. Applications: Mobile phones Power portable electronic devices Some gadgets Electric vehicles Types: Nickel Cadmium(Ni- Cd ) Nickel-Metal Hydride(Ni-MH) Lithium-ion(Li-ion) Lead-Acid

43. Secondary Cells 1.Nickel Cadmium(Ni- Cd ) Ni- Cd batteries are good at maintaining voltage and holding charge when not in use. Material is nickel oxide hydroxide and metallic cadmium as electrodes. these batteries offer good life cycle and good performance at low temperature. Nominal Cell voltage is 1.2V Applications: The small packs are used in portable devices, electronics and toys The bigger ones find in aircraft starting batteries, Electric vehicles and standby power supply

44. 2. Nickel-Metal Hydride Batteries Secondary Cells The chemical reaction at the positive electrode of batteries is similar to that of the nickel–cadmium cell ( NiCd ). The negative electrodes in Nickel-Metal Hydride use a hydrogen-absorbing alloy instead of cadmium which is used in NiCd batteries. Nominal Cell voltage is 2V. Applications: Used in high drain devices because of their high capacity and energy density.

45. Secondary Cells 3. Lithium-ion Batteries Lithium ion batteries are one of the most popular types of rechargeable batteries. Lithium-ion batteries are a type of rechargeable battery in which lithium ions from the negative electrode migrate to the positive electrode during discharge and migrate back to the negative electrode when the battery is being charged. Nominal cell voltage is 3.6-3.85V. Applications: Mobile phones Smart devices Aerospace Military applications due to light weight in nature.

46. Secondary Cells 4. Lead-Acid Batteries Lead acid batteries are a low-cost reliable power workhorse used in heavy duty applications. They are usually very large and because of their weight. Lead acid batteries have very low energy to volume and energy to weight ratios but it has a relatively large power to weight ratio. These are low in cost and attractive for use in several high current applications. Nominal cell voltage is 2V. Applications: Solar-panel energy storage Vehicle ignition and lights High current application like powering automobile starter motors Backup power and load levelling in power generation/distribution.

47. Factors for selecting the battery Factors for selecting the battery 1. Energy Density: The energy density is the total amount of energy that can be stored per unit mass or volume. This determines how long your device stays on before it needs a recharge. 2. Power Density: Maximum rate of energy discharge per unit mass or volume. Low power: laptop, i -pod. High power: power tools. 3. Safety: At high temperatures, certain battery components will breakdown and can undergo exothermic reactions. High temperatures generally reduce the performance of most batteries. 4. Life cycle durability: The stability of energy density and power density of a battery with repeated cycling (charging and discharging) is needed for the long battery life required by most applications. 5. Cost: It is important that the cost of your battery choice is commensurate with its performance and will not increase the overall cost of the project abnormally.

48. Battery Backup It is also called as Uninterruptible power supply (or) online UPS (or) Standby UPS. Applications: Data Centers Industries Hospitals Banks Telecommunications

49. Thank you

50. Problems on Energy Consumption

51. Example-1 A house has the following loads:- 8 lamps-60W each working for 6 hours a day 5 fans-80W each working for 8 hours a day 3 electric heaters-1000W each working for 2 hours a day 1 electric motor 1.5hp working for 4 hours a day Calculate the electricity bill if rate/unit is Rs.1.5/- and Rs.15/- as meter rent for the month of September.

52. Example-2 A workshop is connected with:- 10 fans of 60W each working for 10 hours a day 2 heaters of 1KW each working for 6 hours a day 1 oven of 1.5KW each working for 12 hours a day 15 electric bulbs of 60W each working for 4 hours a day Calculate the electricity bill for the month of 30 days @ 55 paisa/unit.

53. Example-3 A house has the following loads:- 10 lamps of 60W each working for 10 hours a day 1 oven of 450W working for 1 hour a day 8 fans of 80W each working for 2 hours a day 1 heater of 1000W working for 1 hour a day 1 refrigerator of 250W working for 12 hours a day Calculate the monthly electricity bill if rate of charge/unit if Rs.1.20/- plus Rs.20/- as meter rent for the month of June.