Power Plant Guruji

  1.What deals power-system protection ? Ans. Power-system protection is a branch of electrical power engineering that deals  with the protection of electrical power systems. 2.A good electric power system should ensure that ? Ans. A good electric power system should ensure the availability of electrical power  without any interruption to every load connected to it. 3.Power protection systems limit ? Ans. Power protection systems limit the damage at the fault location and prevents  the effects of the fault spreading into the system. 4.What are the nature of faults ? Ans. The nature of fault simply implies any abnormal condition which causes a  reduction in the basic insulation strength between phase conductors, between  phase conductor and earth or any earth screen surrounding the conductors. 5.Voltage breakdown due to ? Ans. Voltage breakdown could be due to normal voltage or abnomal voltage. 6.Causes of faults could be due to ? Ans. Causes of faults could...

  Circuit Breaker A circuit breaker is a switching device that interrupts the abnormal or fault current. It is a mechanical device that disturbs the flow of high magnitude (fault) current and in addition performs the function of a switch. The circuit breaker is mainly designed for closing or opening of an electrical circuit, thus protects the electrical system from damage. Tripping and Auxiliary Supplies Trip Circuit A relay provides a potential free contact, which is shown in the figure as Trip Contact', at the time of fault sensed by the relay. The auxiliary supply goes through this contact to the Trip Coil of the circuit breaker. circuit breaker trip circuit Auxiliary Supply All the circuit breakers are DC (Direct Current) operated. Because DC power can be stored in battery and at the time of total failure of incoming power Occurs, still the circuit breakers can be operated for restoring the situation by this battery. Hence, the battery is another essential item of the powe...

  Function of volute casing in centrifugal pump? Functions of a pump volute: To convert kinetic energy impaired by the impeller into  pressure energy To minimize losses during this energy conversion process The pump casing does not take any part in dynamic head generation The best volutes are of constant velocity design Kinetic energy is converted into pressure energy only in the  diffusion nozzle immediately after the volute throat Various types of volute Single volute Double volute Vertical pump with diffuser Volute with diffuser vanes Circular volute Double Volute A double volute casing has two single volutes 180° apart Total throat area of two volute is same as the throat area of a comparable  single volute Double volute significantly reduces the radial load problem of the  single volute pump Hydraulic performance of a double volute pump is nearly the same as  that of a single volute Double volute pump is around 1-1.5 point less efficient at   B.E....

 Why Use Mechanical Seals ? 1. Lower Mechanical Losses Mechanical seals cause lesser mechanical losses compared to packed glands and thus makes the pump more efficient. Mechanical losses due to frictional drag of the shaft sleeve running against packing account for the largest of the mechanical losses generally incurred in a centrifugal pump. 2. Lesser Sleeve Wear For mechanical seal fitted pumps handling clean, non-corrosive liquids, shaft protecting sleeve can be eliminated. Even where shaft sleeves are used, they are not subject to wear for mechanical seal fitted pumps. In case of packed gland pumps the sleeve under the packing is subjected to wear especially when the pump liquid contains abrasive particles or when the packing sit fixed very tightly on the sleeve. Sleeve damage is costly not only because of the cost of sleeve but also due to the time involved in replacing the worn sleeve with a new one. 3. Seals high pressure as well as low pressure Increased pressure ...

  Voltage Transformer or Potential Transformer Voltage Transformers (VTS) - Importance Voltage transformers are the next  important component of Protection. Voltage Transformers: are used for measuring and protection may be single phase or three phase provide isolation from high voltages must operate in the linear region to prevent accuracy problems must be capable of driving the burden, specified by relay manufacturer Types of Voltage Transformers (VTS)  There are two basic types of VTs-Electromechanical VTs and Capacitor VTS. Electromechanical VTs Are similar to a power transformer May not be economical above 132kV Robust and more reliable Capacitor VTs Used at high voltages (132 Kv or above) Main difference is that CVT has a capacitor divider on the front end Require maintenance as capacitor is used

Gland Seal vs. Mechanical Seal – What’s the Difference? Gland Packing  Advantages Lower initial cost Easily installed & dismantled when lantern rings and glands are split Good reliability to medium pressure  & shaft speed Can handle a large axial  movements (Thermal expansion of stuffing box Vs shaft) Leakage tends to increase gradually, giving warning of impending breakdown Gland Packing Disadvantages Relatively high leakage Requires regular maintenance Wear of shaft & shaft sleeve can be relatively high Power loss may be high Relatively high product loss Mechanical seals Advantages Negligible or no leakage Requires no maintenance Eliminates sleeve wear/shaft wear Very high reliability Can handle higher pressure & speed Application range far wider-Easily applied to carcinogenic, toxic,flammable or radio-active fluids Low power loss Mechanical seals Disadvantages Higher initial cost May require some disassembly of pump parts. Example - Coupl...

   Essential Qualities Of Protection Speed Protective relaying should disconnected a faulty element as quickly as possible. Principal Reasons: Improves power system stability Decreases the amount of damage incurred Decreases the outage time for power consumer Decreases the possibility of severe fault in the up - stream Selectivity Selectivity is the ability of the protective system to determine the point at which the fault occurs by selecting the proper type of protective relay. This gives trip command to the nearest circuit breakers for cleaning the fault and no damage the system. Sensitivity  Sensitivity of a protective scheme refers to the smallest value of actuating quantity at which the protection start operating in relation with the minimum value of fault current in the protection zone. Reliability Reliability means trustworthiness. The relay should not fail to operate in the event of fault in the protective zone. It should not operate unnecessarily without sensing ...

   What is power system protection Power-system protection is a branch of electrical power engineering. It deals with the protection of electrical power system from fault. The objective of a protection scheme is to keep  the power system stable by isolating only the componets that are under fault. The device that are  used to protect the power system from the faults are called protection device Basic Idea Of Protection Relay - Why , What and How ? Power System Protection  Why ? A good electric power system should ensure the availability of electrical power with out any interruption to every load connected to it. What ? Generally power is transmitted through high voltage transmission line and lines are exposed. Therefore, there may be chances of their breakdown due to strom, falling of external objects, and damage to the insulators, etc. These can result not only mechanical damage but also in an electrical fault. Protective relays and relaying systems detects abn...

Pump introduction What is a pump ? Rotating machine which transfer liquid from one place to another or from lower level to higher level. It convert mechanical energy into hydraulic energy. Adds engery to the liquid so as transfer liquid. Adds engery to the liquid so as to transfer liquid : From one elevation to desired elevation by increasing potential energy. Against rsistance at reciver end against resistance in piping system With a desired flow velocity Functions of pump Mechanical energy to Hydraulic energy Kinetic energy Pressure energy Potential energy A pump does not create pressure, it only provides flow. Pressure is a just an indication of the amount of resistance to flow. Types of pump 1.Positive displacement pump 2.Non positive displacement pump Non positive displacement pump 1.jet pump 2.centrifugal pump Positive displacement pump 1.Rotary pump 2.Reciprocating pump Rotary pump 1.Gear pump 2.Lobe pump 3.Screw pump 4.Vane pump Reciprocating pump 1.Piston pump 2.Diaphargam pum...

 A lubricant is a substance placed between two mating surfaces in order to separate them by a thin film reducing the intensity of friction & ensuring a smooth operation.  PURPOSE OF LUBRICANT  1. To reduce friction  2. To prevent wear  3. To prevent adhesion  4. To prevent Corrosion (rust)  5. To cool the moving elements.  6. To cool the surfaces by washing away the metal particles resulting from wear.  7. To ensure a speedy & noiseless operation.  8. To extend the overhaul & services life of the machine.  9. To aid sealing in bearing against the entrance of dirt/ dust.  10. Sometimes as in hydraulic equipments the lubricant actually serves to transmit power one part to another part.  11. To carry away heat generated by friction  12. To reset oxidation  13. To add in distributing the load Mineral Oil: - Mineral oils are mostly used for engine & m/c lubrication as they are cheap & durable....