Draw and explain bulk correction method for power factor & control.

1 Answer

Answer :

Bulk correction method for power factor & control: i) Here individual starter controls the capacitors located at distribution panel. ii) Centralized compensation is employed in large industrial plants where many motors are in use at a time. iii) Capacitors racks are installed at the incoming distribution panel of the industry. iv) These racks are subdivided into steps. v) Current supplied to the distribution panel is monitored by the controller for power factor. vi) Automatic control system switches subdivided rack of capacitor units in steps to maintain P.F. more than preset limit (0.95). 

Related questions

Description : The benefit of power factor correction in a power system is (A) lower power consumption (B) increased demand charge (C) reduced load carrying capabilities in existing lines (D) reduced voltage profile

Last Answer : The benefit of power factor correction in a power system is lower power consumption

Description : Capacitors for power factor correction are rated in?

Last Answer : Capacitors for power factor correction are rated in kVAR.

Last Answer : For power factor correction, synchronous motors operate at no-load and greatly over-excited fields.

Description : Explain spring control method with neat diagram.

Last Answer : Spring Control Method: As shown in the figure the inner ends of the both springs are attahced to the spindle ,while outer end of upper spring is attached to the lever and outer end of ... the springs are twisted in opposite direction to the motion of pointer and produce controlling torque.

Description : How to Choose a Birth Control Method

Last Answer : How to Choose a Birth Control Method Birth control methods depend on the couple's needs and commitment to the method. Some couples just need to prevent pregnancy while others wish to avoid sexually- ... unplanned sex, a broken condom or failure to take birth control pills two days in a row.

Description : Illustrate with neat wiring diagram a single lamp control by two point method.

Last Answer : Single lamp control by two point method:  This system is commonly used for stair case wiring. It consists of two way switches (the switch operates always in one of the two possible positions) the ... the person will change the position of switch S2, so that the lamp will be switched OFF'.

Description : Write one advantage and one disadvantage each for spring control method and gravity control method.

Last Answer : Advantages of Spring Control Method: 1) The spring-controlled meters may be used in any position. 2) In some instruments, springs can be used as current leads. 3) As springs are light in weight ... only. 2) Scale is non-uniform. 3) Control weights add to the weight of instrument.

Last Answer : The main disadvantage of the Ward-Leonard control method is high initial cost, high maintenance cost, low efficiency at light loads.

Last Answer : For constant torque drive armature voltage control speed control method is preferred.

Last Answer : Speed control by Ward Leonard method gives uniform speed variation in both directions.

Description : Discuss how power factor tariff results into energy conservation.

Last Answer : Power factor tariff results into energy conservation: i) Applying incentives and penalties according to power factor is an effective way, which enables consumer to improve power factor so that he can ... finally leads to reduction in the current drawn by the load and helps for energy conservation.

Description : State the incentives and penalties related with power factor tariff.

Last Answer : Incentives and penalties related with power factor tariff: In addition to basic tariff (Maximum Demand Tariff / KVA Maximum Demand Tariff / Load factor tariff) the tariff in which P.F. of ... industrial consumer/H.T/ commercial consumers with contract demand above 80 kw/ 100Kva/107 hp consumer.

Description : A control system having unit damping factor will give  (1) Oscillatory response (2) Undamped response (3) Critically damped response (4) No response

Last Answer : 1

Description : Bulk Glow sticks

Last Answer : If you're planning to use glow sticks for a birthday party or any large event, you'll find the best deal in terms of price if you'll get them by bulk. Your guests will certainly find ... though: the light of these glow sticks last shorter since they consume the energy of the chemicals more rapidly.

Description : State any two disadvantages of one wattmeter method of measurement of 3 phase power.

Last Answer : State any two disadvantages of one wattmeter method of measurement of 3 phase power. Disadvantages of one wattmeter method:- 1. Only used for balanced load 2. It can not be used for ... connection then neutral point must be available 4. Delta connection must be opened to connect current coil.

Description : The power consumed by a balanced 3-ph load is measured by two-wattmeter method. The meter readings are 8 kW and 4 kW. The power factor of the load is (A) zero (B) 0.5 (C) between zero and 0.5 (D) between 0.5 and unity

Last Answer : The power consumed by a balanced 3-ph load is measured by two-wattmeter method. The meter readings are 8 kW and 4 kW. The power factor of the load is between 0.5 and unity

Description : Explain energy conservation method in lighting system by using installation of separate transformer / servo stabilizer.

Last Answer : Energy conservation techniques by installation of separate transformer / servo stabilizer: The luminous efficiency of lamps depends upon the voltage applied across the terminals. It gives its best ... the voltage constant in that installation for giving best luminous efficiency of lamps.

Description : Briefly explain how the power factor of an inductive circuit can be improved.

Last Answer : As we know that power factor should be corrected to ensure that the current supplied is cost friendly. Meaning the power factor should be around one but not greater than one(0.8-0.9) in a ... an inductive circuit due to the inductive reactance which oppose the change of current in the ac circuit. 

Description : With a neat sketch explain working of 1 phase dynamometer type power factor meter.

Last Answer : Working of 1 phase dynamometer type power factor meter : The current coil is connected in series with load. Two pressure coils marked as A and B are connected across the supply terminals ... becomes stationary and the pointer shows steady deflection corresponding to the power factor of the load. 

Description : State the function of following components of a nuclear power station: i) Moderator ii) Shielding iii) Control rod iv) Coolant 

Last Answer : i) Function of Moderator :- Moderator is to moderate or reduce the speed of fast neutron to help the fission process.  ii) Function of sheilding : Shielding is to protect environment, ... from reactor core and transfer it in heat exchanger for producing steam at high pressure and temperature. 

Description : Write function of control rods in nuclear power plant.

Last Answer : Function of control rods in nuclear power plant: The function of control rod is to control the chain reaction in reactor core by adjusting its height.

Description : Regulating-transformers are used in power systems for control of

Last Answer : Regulating-transformers are used in power systems for control of power flow

Description : What is meant by Power factor?

Last Answer : Ans. Power factor means ratio of true power to apparent power. It is cosine of phase angle between voltage and current. Its value is 1 for Unity P.F. Loads, 0 to 1 lagging for inductive loads and o to 1 leading for capacitive loads.

Description : State the effects of low power factor on efficiency and voltage regulation of short transmission lines. 

Last Answer : i) Effect of Low power factor on efficiency:- When power factor of load reduces current drawn by transmission line increases so copper losses in transmission line increases, hence transmission ... increases, so voltage drop in transmission line increases so regulation increases. (Become Poor) 

Description : Why capacitors are used to improve power factor?

Last Answer :  Capacitors generate reactive power instead of that drawn from source which is required by inductive loads.so it reduce the reactive current which is drawn from source to be drawn from capacitor.This control in Electric bills cost.

Description : State the significance of power factor.

Last Answer : Significance of power factor:-  1. Cosine of angle between voltage & current in a circuit is called power factor. 2. It is a measure of the real power in a circuit. 3. Inductive & ... KVA rating equipment 5. Greater conductor size 6. CosØ = R/Z  CosØ= Active Power/ Apparent Power 

Description : A transformer has negative voltage regulation when its load power factor is   (1) Zero (2) Unity (3) Leading (4) Lagging

Last Answer : 0

Description : The power factor of dielectric :  (A) is a function of temperature of the dielectric only (B) depends only on voltage stress to which the dielectric is stressed (C) always constant (D) both (A) and (B)

Last Answer : The power factor of dielectric :  (A) is a function of temperature of the dielectric only (B) depends only on voltage stress to which the dielectric is stressed (C) always constant (D) both (A) and (B)

Description : Power station having Load factor = 70%, capacity factor = 50%, used factor = 60%, maximum demand = 20MW then annual energy production is  (1) 122.8 GWh (2) 198.55 GWh (3) 128.2 GWh (4) 188.82 GWh

Last Answer : Power station having Load factor = 70%, capacity factor = 50%, used factor = 60%, maximum demand = 20MW then annual energy production is 122.8 GWh

Description : In a synchronous generator delivering lagging power factor load  (1) the excitation emf leads terminal voltage by the power angle (2) the excitation emf lags terminal voltage by the power angle (3) ... by the power factor angle (4) excitation emf lags the terminal voltage by the power factor angle

Last Answer : In a synchronous generator delivering lagging power factor load the excitation emf leads terminal voltage by the power angle

Description : What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these

Last Answer : What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these

Description : The power factor angle and torque angle of a salient pole synchronous generator drawing a current of 1.0 pu from a lagging load are 45o and 15o, respectively. The direct axis and quadrature axis currents, respectively, are (A) 0.5 pu ... pu, 0.5 pu (C) 0.707 pu, 0.707 pu (D) 0.5 pu, 0.5 pu

Last Answer : The power factor angle and torque angle of a salient pole synchronous generator drawing a current of 1.0 pu from a lagging load are 45o and 15o, respectively. The direct axis and quadrature axis currents, respectively, are 0.866 pu, 0.5 pu

Description : The power factor of a D.C. circuit is always?

Last Answer : The power factor of a D.C. circuit is always unity.

Description : The ratio of active power to apparent power is known as____ factor.

Last Answer : The ratio of active power to apparent power is known as power factor.

Description : The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is?

Last Answer : The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is 32 kW.

Description : Power factor of electric bulb is?

Last Answer : Power factor of electric bulb is unity.

Description : The power factor at resonance in R-L- C parallel circuit is?

Last Answer : since a rlc circuit at resonance behaves like a pure resistive circuit, i.e there is no phase difference between current and voltage, hence the power factor is unity.

Description : Power factor of the system is kept high?

Last Answer : Power factor of the system is kept high to reduce line losses, to maximise the utilization of the capacities of generators, lines and transformers, to reduce voltage regulation of the line.

Description : Power factor of an inductive circuit is usually improved by connecting capacitor to it in?

Last Answer : Power factor of an inductive circuit is usually improved by connecting capacitor to it in parallel.

Description : Poor power factor?

Last Answer : Poor power factor reduces load handling capability of electrical system, results in more power losses in the electrical system, overloads alternators, transformers and distribution lines, results in more voltage drop in the line.

Description : Power factor of an electrical circuit is equal to?

Last Answer : Power factor of an electrical circuit is equal to R/Z, cosine of phase angle difference between current and voltage, kW/kVA.

Last Answer : The power factor of a single phase load can be calculated if the instruments available are three ammeters or three voltmeters.

Last Answer : In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at 120°.

Last Answer : In a single phase power factor meter the phase difference between the currents in the two pressure coils is exactly 90°.

Last Answer : The two pressure coils of a single phase power factor meter have the same dimensions and the same number of turns.

Last Answer : A power factor meter has one current circuit and two pressure circuits.

Last Answer : In a low power factor wattmeter the compensating coil is connected in series with pressure coil.

Last Answer : In a low power factor wattmeter the pressure coil is connected to the load side of the current coil.

Last Answer : When a D.C. series motor is connected to A.C. supply, the power factor will be low because of high inductance of field and armature circuits.

Last Answer : The power factor of a single-phase induction motor is usually lagging.