Power plant and calculations

Saturday, 26 August 2023

Power plant manager interview questions


 










Power plant manager interview questions

General questions

Can you describe your qualification, experience and background in power plant management?

lCan you describe your experience with different types of power generation technologies, such as coal, natural gas, nuclear, renewable (solar, wind, hydro), etc.?

lWhy do you want to change the job?

lWhat are your strengths and weakness?

lHow do you manage a team of technicians and operators? Can you share your approach to delegation, motivation, and conflict resolution?

How do you stay updated with the latest advancements and trends in power plant technology and regulations?

 

Leadership and Management:

What is your approach to leading a team of engineers, technicians, and support staff in a power plant environment?

How do you prioritize tasks and delegate responsibilities to ensure smooth plant operations?

Can you provide an example of a situation where you had to resolve a conflict among your team members? How did you handle it?

Power plant operations require strict adherence to schedules and deadlines. How do you manage time-sensitive situations effectively?

Power plant emergencies can be high-pressure situations. Can you share an experience where you successfully managed a crisis or emergency at a power plant?

Effective communication is crucial in your role. How do you ensure clear and efficient communication between different departments and management?

Describe your experience with regulatory compliance in the power generation industry. How do you ensure your plant meets all necessary regulations?

Power plant operations can be physically demanding and require long hours. How do you ensure the well-being and morale of your team?

 Safety and Regulatory Compliance:

 What is your approach to ensuring strict adherence to safety protocols and regulations within a power plant environment?

How do you ensure the safe and efficient operation of a power plant? What safety protocols do you implement?

Can you discuss your experience with permitting, licensing, and compliance with environmental regulations for power plants?

How do you maintain and promote a culture of safety among your team members?

What measures do you take to stay updated on the latest safety standards and regulatory changes in the power generation industry?

How you versed with factory and labour acts? Explain briefly

Personal and Career Development:

What inspired you to pursue a career in power plant management?

How do you ensure your skills and knowledge are up-to-date in this rapidly evolving field?

Can you discuss any professional certifications, licenses, or relevant training you hold?

What is your long-term vision for your career in power plant management?

How do you handle stress and pressure in a demanding role like power plant management?

 Technical

Read>>>.Powerplant O&M reference books

Can you provide an overview of your experience in managing power plants? What types of power plants have you worked with?

How do you ensure the safe and efficient operation of a power plant? What safety protocols do you implement?

Can you discuss your approach to preventative and corrective maintenance in a power plant setting?

What strategies do you employ to optimize the efficiency and output of a power plant while minimizing operational costs?

Power plants are transitioning towards cleaner energy sources. Can you explain your familiarity with renewable energy technologies and their integration into power generation?

How do you stay updated with the latest advancements and trends in power plant technology and regulations?

Describe a challenging technical issue you've encountered in the past at a power plant. How did you handle it?

How do you improve heat rate of power plant?

What strategies you do use in improving the efficiency of the power plant

How do you calculate the power generation cost?

Can you discuss a situation where you had to troubleshoot a complex operational issue in a power plant? How did you go about identifying and resolving the problem?

What are the major challenges you have faced in power plant maintenance?

What are the major challenging situations you have faced in Water treatment plant?

How do manage the spare and consumables budget? What is your strategy?

What strategies do you employ to ensure the regular maintenance and upkeep ofequipment in the power plant? How do you manage maintenance schedules and unexpected breakdowns?

How do you improve specific steam consumption in steam Turbines?

What are the reasons for increase in specific steam consumption in steam Turbines?

How does vacuum relate to specific steam consumption?

Briefly explain the maintenance activities carried out in Turbine major overhauling?

What do you mean by cavitation in centrifugal pumps?

What are the different interlocks provided for Turbine and Generators?

What are class A & class B trips? Explain briefly

Briefly explain the power generation phenomenon in steam turbo generators?

What are the different types of circuit breakers used in electrical system?

What do you mean by switch gears in electrical system?

Power outages and unexpected disruptions can occur. How do you develop and implement contingency plans to minimize downtime and production losses?

Could you discuss your approach to managing budgets, controlling costs, and identifying opportunities for cost savings without compromising plant performance or safety?

How do you reduce power generation cost?

What are the critical parameters of water to be monitored to avoid stoppages of power plant? And why?

Read >>>> practical approach to powerplant operation and maintenance

What do you mean by SOP, SMP and OCP?

What are the KPIs of operation?

What do you mean by MTTR & MTBF?

What do you mean by proactive maintenance?

What are the various advantages of Preventive maintenance over break down maintenance?

What do you mean by CBM?

What are the tests/inspection carried out in Boiler RLA study?

Why RLA study is so important?

Being a Boiler expert what are your plan of actions to reduce fuel consumption?

How do you reduce plant auxiliary power consumption?

What are the major equipment contributing auxiliary power consumption?

What are the requirements of yearly electrical inspection?

What is the significance of thermal expansion in Boilers?

What are the various energy conservation opportunities in power plant?

How do you calculate the Turbine heat rate?

How do you improve the performance of centrifugal pumps and fans?

What are the major troubleshooting associated with Boiler feed pumps?

How do you co-relate with enthalpy and steam pressure?

What amount of heat is required to raise the feed water temperature from 100 deg C to 150 deg C?

How do you improve the efficiency of steam Turbines?

Also read >>>Top-85 interview  questions for power plant shift incharge

For more >>>>read Powerplant and calculations

Saturday, 19 August 2023

Why do turbines go into over speed trip???

 





A turbine rotor can go into over speed when its rotational speed exceeds its designed or safe operating limits. This can occur in various types of turbines, such as steam turbines, gas turbines, or even wind turbine.A turbine rotor can go into over speed when its rotational speed exceeds its designed or safe operating limits. This can occur in various types of turbines, such as steam turbines, gas turbines, or even wind turbine.

 Now a days steam turbines are designed for rotation speed more than 10000 RPM.For low capacity turbines the speed is generally more than that of high capacity turbines.

 Following are the most relevant reasons for Turbines to go into high speed or over speed.

 Sudden Load Loss: If the load on the turbine suddenly decreases, the turbine may accelerate beyond its design limits due to the reduced resistance. This can occur, for example, if there's a sudden disconnection of the load or if a generator or other equipment connected to the turbine experiences a fault.

Malfunctioning Governor: Turbines often have governors that control the amount of steam input to the turbine in order to maintain a specific rotational speed. If the governor malfunctions, it might not be able to regulate the turbine's speed properly.

Sudden cut off of extraction steam:Sudden cut off or closure of extraction steam valve may leads to over speed of Turbine.

Control System Failure: The control systems that regulate the speed of a turbine may malfunction, leading to an inability to control the turbine's speed effectively. This can occur due to electrical failures, software glitches, or other issues with the control system.

Loss of Blade Load: Turbine blades are designed to extract energy from the fluid (steam, gas, or water) passing through them. If there's a sudden drop in the fluid flow rate or pressure, the blades might not experience enough load to keep the turbine's speed in check, leading to over speed.

Read >>>Practical approach to power plant operation and maintenance

Failure of Throttle valves: Damages to the any of the throttle valve lead to over speed of the Turbines

Stuck up of throttle valves: Stuck up of throttle valves due to burs, scoring marks or due to dust and dirt may lead to over speed of the Turbines

Looseness in linkages:Looseness in HP or KP valve linkages may lead to mal-operation of the throttle valves leading into more steam flow and hence over speed of the Turbine

 To prevent overspeed and its potentially catastrophic consequences, turbines are equipped with safety measures such as mechanical overspeed protection systems, which may include centrifugal force-based devices that trip and reduce the flow of fluid into the turbine when a certain rotational speed is exceeded. Regular maintenance, monitoring, and adherence to operational guidelines are essential to ensure the safe and reliable operation of turbines.

Read more>>>Powerplant and calculations

Tuesday, 8 August 2023

Generator and Turbine intertripping interlocks



Case-1

 On tripping of class A trip of Generator

1-Generator breaker opens

2-Excitation switches off

3-Turbine trips on 86 T relay and followed by closing of ESV and all extractions

4-Turbine speed increases a bit by around 2-3% and gradually speed recedes

 Case-2

 On tripping of class-B trip of Generator

 1-Only generator breaker opens and excitation switches off

2-Turbine rotates on rated speed

3-After normalization of problem, generator synchronized with auxiliary power supply unit and later with grid

4-In case of small turbines, STG clubbed with 86GA to trip Turbine also

 Case-3

 On tripping due to Turbine fault

 1-Relay 86 T gets activated to close turbine ESV all extractions

2-Low forward power or Reverse Power Relay activates first which has time delay, during this time entrapped energy gets consumed by generator

3-Subsequently 86 G relay gets activated to open Generator breaker and followed by excitation gets off

4-Turbine speed does not increase in this case

 Trend of rotor speed on tripping of Turbine and Generator











Read>>>>Powerplant O&M reference books

 On tripping of Generator, instantly generator breaker gets opened and Turbine emergency valve closes.So steam entrapped in Turbine casing causes increase in speed initially and later slows down.

On the other hand,when turbine trips first, generator breaker opens after some time delay through Low forward power or Reverse Power Relay.This time delay helps turbine to consume entrapped steam in casing.As a result turbine generates power and does not allow speed to increase more.

 Relays and significance

Sl No.

Type of relay

Used for

1

86-G

Generator lock out relay

2

86-T

Turbine lock out relay

3

59-G

Generator over voltage @110% alarm and 120% trip

4

27-G

Generator under voltage @90% alarm and 80% trip

5

 81-U

Generator Under frequency

6

81-O

Generator over frequency

7

32-P

Generator Reverse Active Power  5 % of Active Power

8

 32Q

Generator Reverse Reactive Power

9

37 

Low forward Power

10

46

Negative Phase Sequence 

11

49

Generator Over Load

12

 50

Generator Instantaneous O/C    

13

64N

Restricted E/F

14

64R

Rotor E/F2nd Stage




Thursday, 29 June 2023

Topping cycle & calculations

  Topping cycle & calculations




 







A Co-generation system can be classified as either a topping cycle or a bottoming cycle on the basis of sequence of energy generated & use.

 In a topping cycle, the fuel supplied is used to first produce power and then thermal energy, which is the by-product of the cycle and is used to satisfy process heat requirements.

 In a topping cycle, a primary heat source, such as a gas turbine or an internal combustion engine, is used to drive a generator and produce electricity. The primary cycle typically operates at higher temperatures and generates high-pressure and high-temperature exhaust gases.

 The exhaust gases from the topping cycle are then directed to a waste heat recovery boiler or a heat exchanger, where their residual heat is captured. This waste heat is then used to produce steam, which drives a steam turbine or an organic Rankine cycle (ORC) turbine in the bottoming cycle.

 Topping cycles are commonly used in combined cycle power plants, where they offer improved efficiency and performance compared to standalone gas turbines or internal combustion engines. The integration of a bottoming cycle allows for the utilization of waste heat, maximizing the overall energy output of the system.

 In a bottoming cycle, the primary fuel used produces high temperature thermal energy and the heat rejected from the process is used to generate power through a heat recovery Boiler & Turbo generator.

 Bottoming cycles are suitable for manufacturing processes that require heat at high temperature in furnaces & kiln and reject heat at significantly high temperatures.

 The bottoming cycle operates at lower temperatures and utilizes the waste heat energy to generate additional power. By extracting energy from the waste heat, the topping cycle achieves higher overall efficiency compared to a single-cycle power generation system.

 Topping cycle calculation:

 A Co-generation facility is defined as one, which simultaneously produces two or more forms of useful energy such as electrical power and steam, electric power and shaft (mechanical) power, etc.” The project may qualify to be termed as a co-generation project, if it is in accordance with the definition and also meets the qualifying requirement outlined below:

 Topping cycle mode of co-generation – Any facility that uses non-fossil fuel input for the power generation and also utilizes the thermal energy generated for useful heat applications in other industrial activities simultaneously.

 For the co-generation facility to qualify under topping cycle mode, the sum of useful power output and one half the useful thermal output be greater than 45% of the facility’s energy consumption, during season.”


Read >>>>Powerplant O&M reference books

Following inputs required for calculation of topping cycle:

  • Fuel consumption
  • Fuel GCV
  • Steam given to processes & their heat content
  • Power generation

Topping cycle is calculated by using following formula

 TC Eff = (Sum of total heat supplied to process in kcal X 50% + Total electricity generated in kcal) X 100 / Fuel energy

Example

 A 44 MW Co-generation plant is operating at 41 MW load and utilizing bleed & extraction steam for process heating. Calculate the topping cycle efficiency

The inputs required are as below

Sl No

Particular/Parameters

UOM

Value

1

Boiler fuel consumption

TPH

85

2

Fuel GCV

Kcal/kg

2250

3

Process-1 steam flow

TPH

12

4

Process steam-1 enthalpy

Kcal/kg

740

5

Process-2 steam flow

TPH

170

6

Process steam-2 enthalpy

Kcal/kg

653

7

Power generation

MWH

41

 Calculation:

Total heat content in input fuel = 85 X 1000 X 2250 =191250000 kcal

Heat content in process-1 steam = 12 X 1000 X 740 =8880000 kcal

Heat content in process-2 steam = 170 X 1000 X 653 =111010000 kcal

Power generation in kcal = 41 X 1000 X 860 = 35260000 kcal

 TC Eff = (Sum of total heat supplied to process in kcal X 50% + Total electricity generated in kcal) X 100 / Fuel energy

TC Eff = ((8880000+111010000) X 50% + 35260000) X 100 / 191250000

 TC eff = 49.78%

   

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For more >>>>read powerplant and calculations

Online calculation of centrifugal pump power

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