4BE3.5 CU4 C6 Obj 4 EMH

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Questions and Answers

EASY What should plant operators be well versed in during an electrical power failure?

Firefighting procedures

First aid techniques

Electrical wiring practices

Plant blackout procedures (correct)

What happens to electrically powered equipment during a power failure?

It stops, unless connected to an uninterruptable power source (UPS) (correct)

It automatically restarts when power is restored

It continues to operate on backup power

It slows down to conserve energy

Which equipment will restart automatically when power is restored?

Main boiler pumps

Centrifugal pumps

Large air compressors

Lighting and power receptacles (correct)

What should operators know about control valves during an electrical power failure?

The positions in which they fail (open, shut, or last position) Signup and view all the answers

What is a critical aspect of restarting equipment after a power failure?

Following a specific sequence for restarting equipment Signup and view all the answers

What should operators know about electrical equipment during an electrical power failure?

How equipment is fed by standby power, and what is not Signup and view all the answers

What can be used to manually operate an automatic transfer switch during an electrical power failure?

A manual transfer switch Signup and view all the answers

What is an important consideration during an electrical power failure?

Plant load shedding strategies Signup and view all the answers

What is the purpose of a UPS system in a power plant?

To maintain power to critical equipment at all times through a system of batteries and inverters Signup and view all the answers

What happens to valves during a power failure?

They fail safe Signup and view all the answers

What is the purpose of a seal oil pump?

To keep hydrogen coolant inside large alternators Signup and view all the answers

What can cause a loss of boiler feedwater?

Failure of the boiler feedwater pump or control valve Signup and view all the answers

What is the purpose of a low water alarm?

To alert the operator of a low water level Signup and view all the answers

What is a possible cause of feedwater pump failure?

Electrical failure of the pump drive motor Signup and view all the answers

What should be done if the boiler feedwater pump trips?

Start the standby boiler feedwater pump Signup and view all the answers

What is the purpose of circulating hot feedwater through the standby pump?

To keep the pump hot and ready for service Signup and view all the answers

What is a possible cause of a low water condition?

Loss of boiler feedwater due to pump or control valve failure Signup and view all the answers

What is the purpose of a UPS system's automatic transfer switch?

To connect the batteries and inverter to critical loads Signup and view all the answers

What could be a reason for the failure of the feedwater control valve?

Control instrumentation failure Signup and view all the answers

What should you do if the boiler feedwater pumps are supplying feedwater at the correct pressure?

Check the position of the feedwater control valve stem Signup and view all the answers

What could happen if a condensate transfer pump fails?

Deaerator will be pumped dry Signup and view all the answers

What is a sign of an open or defective blowdown valve?

The blowdown lines are hot Signup and view all the answers

What should you do if a boiler trips on low water?

Close the pilot and main test firing valves Signup and view all the answers

Why must a boiler be inspected after a low water condition?

To check for damage to the boiler tubes Signup and view all the answers

What is a consequence of an improperly functioning low water cut-off device?

The boiler will overheat Signup and view all the answers

What should you do if the feedwater control valve is suspected of being damaged?

Remove it from service and repair it Signup and view all the answers

Why must the boiler be cooled before inspection?

To inspect for damage Signup and view all the answers

What could cause the deaerator water level to drop?

A faulty condensate return pump Signup and view all the answers

What can cause excessive fuel pressure in a main flame?

Improperly adjusted fuel pressure regulator Signup and view all the answers

What can cause inadequate fuel pressure in a main flame?

Improperly adjusted fuel pressure regulator Signup and view all the answers

What is the purpose of the high fuel pressure cut-off switch?

To trip the boiler in case of high fuel pressure Signup and view all the answers

What can cause inadequate atomizing medium pressure?

Blockage in the fuel strainer Signup and view all the answers

What should be done to the fuel strainer if the fuel oil supply pressure is low?

Stop the pump and clean the strainer Signup and view all the answers

Why may UV scanners need to be replaced?

After 40 000 hours of use Signup and view all the answers

What can happen to flame rods over time?

They warp and come out of alignment Signup and view all the answers

What should be ensured during annual burner maintenance?

Flame rods are clean and properly aligned Signup and view all the answers

What can cause flame instability in a main flame?

All of the above Signup and view all the answers

Who should be contacted to adjust the fuel pressure and the high fuel pressure cut-off?

Certified burner technician, oil fitter, or Class A gas fitter Signup and view all the answers

What type of equipment is typically used in power plants?

Fuel oil pumps and boiler feedwater pumps Signup and view all the answers

When a power failure occurs, what happens to valves that fail open?

They fail to a safe position Signup and view all the answers

What should the operator do immediately after a power failure?

Check the fuel safety shut-off valves Signup and view all the answers

What happens to the boiler feedwater regulating valves during a power failure?

They fail closed Signup and view all the answers

What is the purpose of banking the fire in a solid fuel boiler?

To smother the fire and prevent steam generation Signup and view all the answers

What should the operator do with the boiler steam outlet valves during a power failure?

Close them to prevent steam flow Signup and view all the answers

What is the purpose of an Emergency Power Supply System (EPSS)?

To supply long-term power to essential loads Signup and view all the answers

What should the operator do with the breakers in an electrical distribution room during a power failure?

Open them to prevent overloading Signup and view all the answers

What happens to the fuel line safety shut-off valves during a power failure?

They fail closed Signup and view all the answers

What is the purpose of automatic load-shedding equipment in an EPSS?

To shed non-essential loads during power failure Signup and view all the answers

What is the consequence of an FD fan failure if the combustion air proving switch does not shut down the burner?

Explosive conditions may arise in the furnace. Signup and view all the answers

What should be done immediately if the combustion air proving switch fails to operate?

Shut the main and pilot test firing valves. Signup and view all the answers

Why is it important to allow air to enter the furnace after shutting down the boiler?

To sweep carbon monoxide and unburned fuel from the furnace. Signup and view all the answers

Who should be contacted to replace and adjust the combustion air proving switch?

A certified burner technician, oil fitter, or Class A gas fitter. Signup and view all the answers

What should be done after repairing the FD fan failure?

Thoroughly purge the furnace prior to beginning a normal restart. Signup and view all the answers

What is the consequence of a failure of the electric motor, fan bearing, coupling, or fan belt?

The FD fan may fail. Signup and view all the answers

What should you do if the water level is outside of the visible portion of the gauge glass?

Blow down the gauge glass Signup and view all the answers

What should you do if the boiler water level is below the lowest visible part of the gauge glass?

Shut the boiler down and let it cool slowly Signup and view all the answers

What is a potential consequence of a high boiler water level?

Severe and destructive water hammer Signup and view all the answers

What should you do when a flame failure occurs?

Shut the pilot and main test firing valves and investigate the cause Signup and view all the answers

What may cause a flame failure during the pilot trial for ignition period?

Inadequate pilot flame during the ignition period Signup and view all the answers

What is recommended by ASME CSD-1 for automatically fired boilers?

Annual pilot turndown test Signup and view all the answers

What should you do if the pilot flame fails during pilot ignition?

Contact a certified burner technician Signup and view all the answers

What is a possible cause of flame failure during the run period?

All of the above Signup and view all the answers

What should you do after correcting the cause of a flame failure?

Carefully test the operation of the flame safeguard controls Signup and view all the answers

What may occur if excessive combustion air is provided during the pilot trial for ignition period?

The pilot flame will be blown out Signup and view all the answers

MEDIUM What is the primary purpose of a UPS system in a power plant?

To provide backup power to critical equipment during a power failure Signup and view all the answers

What happens to valves during a power failure?

They fail safe to prevent damage Signup and view all the answers

What is the purpose of a low water alarm?

To alert operators to a potential low water condition Signup and view all the answers

What is a common cause of feedwater pump failure?

All of the above Signup and view all the answers

What is the purpose of circulating hot feedwater through the standby pump?

To keep the pump warm and ready for operation Signup and view all the answers

What is a critical aspect of restarting equipment after a power failure?

Restarting in a specific order Signup and view all the answers

What is the purpose of a seal oil pump?

To vent hydrogen from the alternator Signup and view all the answers

What can cause a loss of boiler feedwater?

Both A and B Signup and view all the answers

What happens when a power failure occurs?

Critical equipment stops, and some may restart automatically Signup and view all the answers

What is the purpose of an Emergency Power Supply System (EPSS)?

To provide backup power to essential loads Signup and view all the answers

What is the primary concern for an operator during a power failure?

Ensuring the fire is extinguished Signup and view all the answers

What happens to heating system control valves during a power failure?

They fail open Signup and view all the answers

What is the purpose of closing the main and pilot test firing valves during a power failure?

To prevent an unattended light-off Signup and view all the answers

What is the function of an Emergency Power Supply System (EPSS)?

To supply long-term power to essential loads Signup and view all the answers

Why is it important to open all breakers in an electrical distribution room during a power failure?

To protect the EPSS bus from being overloaded Signup and view all the answers

What happens to boiler feedwater regulating valves during a power failure?

They fail closed Signup and view all the answers

What is the purpose of banking the fire in a solid fuel boiler during a power failure?

To smother the fire Signup and view all the answers

What should the operator do with the boiler steam outlet valves during a power failure?

Close them Signup and view all the answers

What happens to fuel line safety shut-off valves during a power failure?

They fail closed Signup and view all the answers

What is the purpose of automatic load-shedding equipment in an EPSS?

To protect the EPSS bus from being overloaded Signup and view all the answers

During a power failure, which of the following types of equipment typically restarts automatically when normal power is restored?

Lighting and power receptacles Signup and view all the answers

What is a critical consideration for plant operators during an electrical power failure?

Restarting equipment in the correct sequence Signup and view all the answers

What should you do if the boiler water level is below the lowest visible part of the gauge glass?

Shut the boiler down and let it cool slowly Signup and view all the answers

What is the purpose of load shedding strategies in a power plant?

To prioritize power distribution to critical equipment Signup and view all the answers

What should plant operators know about control valves during an electrical power failure?

Their failure position depends on the type of valve Signup and view all the answers

What could cause severe and destructive water hammer?

High boiler water level Signup and view all the answers

What should you do if the flame fails during pilot ignition?

Contact a certified burner technician Signup and view all the answers

What is the purpose of a standby generator in a power plant?

To provide backup power during electrical power failures Signup and view all the answers

What is a possible cause of flame failure?

All of the above Signup and view all the answers

What is a potential consequence of not restarting equipment in the correct sequence after a power failure?

Instability in the plant's operations Signup and view all the answers

What should you do if the boiler operates with its water level below the lowest visible part of the gauge glass?

Shut the boiler down and let it cool slowly Signup and view all the answers

What should plant operators do if a standby generator fails to start automatically during a power failure?

Try to manually start the generator Signup and view all the answers

What is the purpose of the pilot turndown test?

To establish the minimum pilot flame size Signup and view all the answers

What is a key consideration for plant operators when responding to an electrical power failure?

Following established procedures for responding to power failures Signup and view all the answers

What should you do if the boiler water level is above the highest visible part of the gauge glass?

Blow off the water column and gauge glass Signup and view all the answers

What can cause an influx of feedwater to rapidly evaporate?

Adding water to the boiler to restore the water level Signup and view all the answers

What should you do if the safety valve try lever is operated?

Do not operate the safety valve try lever Signup and view all the answers

What should you do if damage is suspected or there are signs of overheated surfaces?

Notify the chief engineer and the jurisdictional boiler inspector Signup and view all the answers

What should be done if a draft fan fails and the combustion air proving switch fails to shut down the burner?

Close the FD fan damper and shut the main and pilot test firing valves Signup and view all the answers

Why is it important to close the FD fan damper after an FD fan failure?

To prevent explosive conditions in the furnace Signup and view all the answers

What should be done to the furnace after shutting down the boiler due to an FD fan failure?

Allow air to enter the furnace through the fan damper Signup and view all the answers

What is the consequence of an FD fan failure if the combustion air proving switch does not shut down the burner?

The flame becomes excessively smoky Signup and view all the answers

Who should replace and adjust the combustion air proving switch?

A certified burner technician, oil fitter, or Class A gas fitter Signup and view all the answers

What is the final step in rebooting the boiler after an FD fan failure?

Thoroughly purge the furnace prior to restarting the boiler Signup and view all the answers

What can cause a main flame to be unstable?

All of the above Signup and view all the answers

What should trip the boiler if the fuel pressure is too high?

High fuel pressure cut-off switch Signup and view all the answers

What can cause inadequate fuel pressure in an oil burner?

All of the above Signup and view all the answers

What should be done to the fuel strainer if the fuel oil supply pressure is low?

Clean or replace the fuel strainer Signup and view all the answers

Why may UV scanners need to be replaced?

They can fail sooner if exposed to high temperature Signup and view all the answers

What should be ensured during annual burner maintenance?

Flame rods are clean and properly aligned Signup and view all the answers

What can happen to flame rods over time?

They can warp and come out of alignment Signup and view all the answers

What should be contacted to adjust the fuel pressure and the high fuel pressure cut-off?

Certified burner technician Signup and view all the answers

What can cause flame instability in a main flame?

All of the above Signup and view all the answers

What can happen if the combustion air proving switch fails to operate?

A failure in combustion air can occur Signup and view all the answers

What should be suspected if the feedwater control valve stem is fully open, but the boiler water level is still low?

Feedwater blockage downstream of the control valve Signup and view all the answers

What can happen if a condensate transfer pump fails?

The deaerator can be pumped dry by the boiler feedwater pumps Signup and view all the answers

What should be checked first if the boiler water level is low and the feedwater control valve is fully open?

The condensate return tank level Signup and view all the answers

What is a possible cause of a low boiler water level?

Feedwater blockage downstream of the control valve Signup and view all the answers

What should be done if the boiler trips on low water?

Close the pilot and main test firing valves Signup and view all the answers

What can cause damage to boiler tubes?

Waterside corrosion Signup and view all the answers

What should be done if the feedwater control valve is suspected of being damaged?

Remove the valve from service and repair it promptly Signup and view all the answers

What can cause a low water condition in the boiler?

All of the above Signup and view all the answers

What should be done if the boiler feedwater pumps are supplying feedwater at the correct pressure, but the boiler water level is still low?

Check the feedwater control valve stem position Signup and view all the answers

What is a consequence of an improperly functioning low water cut-off device?

Metal surfaces can overheat and weaken Signup and view all the answers

During a power failure, which valve fails open?

Heating system control valves Signup and view all the answers

What is the purpose of opening drum vents after a power failure?

To prevent overheating of the superheater tubes Signup and view all the answers

What is the purpose of an Emergency Power Supply System (EPSS)?

To supply long-term power to essential loads Signup and view all the answers

What should the operator do immediately after a power failure?

Check the fuel safety shut-off valves Signup and view all the answers

What happens to fuel line safety shut-off valves during a power failure?

They fail shut Signup and view all the answers

What is the purpose of banking the fire in a solid fuel boiler?

To extinguish the fire Signup and view all the answers

HARD What should the operator do with the boiler steam outlet valves during a power failure?

Close them to prevent steam release Signup and view all the answers

What is the purpose of automatic load-shedding equipment in an EPSS?

To disconnect non-essential loads during a power failure Signup and view all the answers

What happens to boiler feedwater regulating valves during a power failure?

They fail shut Signup and view all the answers

What should the operator do with the breakers in an electrical distribution room during a power failure?

Close them to prevent electrical shock Signup and view all the answers

What could cause a boiler to trip on low water?

All of the above Signup and view all the answers

What should be checked first if a feedwater control valve fails?

The position of the feedwater control valve stem Signup and view all the answers

What may indicate a problem with the boiler blowdown or blowoff valves?

Hot blowdown and blowoff lines Signup and view all the answers

What should be done if the boiler feedwater pumps are supplying feedwater at the correct pressure?

Check the position of the feedwater control valve stem Signup and view all the answers

What could happen if the condensate transfer pump fails?

The deaerator level will drop Signup and view all the answers

What should be done if the deaerator water level cannot be restored?

Shut down the boilers until the cause is determined and corrected Signup and view all the answers

What should be done if the boiler trips on low water?

Close the pilot and main test firing valves Signup and view all the answers

What is a possible cause of a low water condition in the boiler?

All of the above Signup and view all the answers

What should be done if the feedwater control valve is suspected of being damaged?

Remove the valve from service and repair it promptly Signup and view all the answers

Why must the boiler be cooled before inspection?

To ensure safety during inspection Signup and view all the answers

What is a critical consideration for plant operators when restarting equipment after a power failure?

The equipment is critical to plant operation and must be restarted in a specific sequence Signup and view all the answers

What is the primary purpose of a UPS system in a power plant?

To provide backup power to critical equipment Signup and view all the answers

What is a common strategy for dealing with electrical power failures in a power plant?

Load shedding to reduce power demand Signup and view all the answers

What is a key consideration for plant operators when dealing with control valves during an electrical power failure?

The valves will fail in their last position Signup and view all the answers

What is the purpose of a standby generator in a power plant?

To provide backup power to critical equipment Signup and view all the answers

What is a common issue with electrical equipment during an electrical power failure?

The equipment will require manual restart Signup and view all the answers

What is a key consideration for plant operators when responding to an electrical power failure?

The power failure requires immediate and effective response Signup and view all the answers

What is the purpose of an automatic transfer switch in a power plant?

To switch to standby power generation during a power failure Signup and view all the answers

What is the primary purpose of a Uninterruptible Power Supply (UPS) system in a power plant?

To maintain power to critical equipment during a power failure Signup and view all the answers

What is the typical duration of power supply from a UPS system's battery?

Up to 6 hours Signup and view all the answers

What is the primary function of a seal oil pump?

To prevent hydrogen leakage from the alternator Signup and view all the answers

What is the consequence of a failed feedwater control valve?

Low water level in the boiler Signup and view all the answers

What is the purpose of a low water alarm in a power plant?

To alert the operator to investigate the cause of low water level Signup and view all the answers

What is the recommended action if the standby feedwater pump is not automatic?

Start the standby pump manually Signup and view all the answers

What is the purpose of circulating hot feedwater through the standby pump?

To keep the pump hot and ready for operation Signup and view all the answers

What is a possible cause of feedwater pump failure?

Failure of the pump drive belt Signup and view all the answers

What should be done if the boiler feedwater pump trips?

Start the standby pump manually Signup and view all the answers

What is the consequence of a loss of boiler feedwater?

Low water level in the boiler Signup and view all the answers

What should be done if the boiler water level is below the lowest visible part of the gauge glass?

Shut the boiler down and let it cool slowly Signup and view all the answers

What could be the cause of flame failure during the pilot trial for ignition period?

All of the above Signup and view all the answers

What should be done to the pilot flame if it fails during pilot ignition?

Contact a certified burner technician Signup and view all the answers

What is the purpose of blowoff valves in high boiler water level situations?

To lower the boiler water level Signup and view all the answers

What should be done if the boiler operated with its water level below the lowest visible part of the gauge glass?

Isolate, cool, drain, and open up for internal inspection Signup and view all the answers

What is a consequence of an improperly functioning low water cut-off device?

Boiler overheating and damage Signup and view all the answers

Why must the boiler be cooled before inspection?

To ensure safe internal inspection Signup and view all the answers

What is the purpose of the annual pilot turndown test?

To establish the minimum pilot flame size Signup and view all the answers

What should be done if the boiler water level is above the highest visible part of the gauge glass?

Blow off the water column and gauge glass Signup and view all the answers

Who should be contacted to adjust the pilot flame?

A certified burner technician Signup and view all the answers

What may arise in the furnace due to the presence of unburned fuel if an FD fan fails and the combustion air proving switch does not shut down the burner?

Explosive conditions Signup and view all the answers

What should be done if the combustion air proving switch fails to operate?

Immediately shut the main and pilot test firing valves Signup and view all the answers

Who should replace and adjust the combustion air proving switch?

A certified burner technician Signup and view all the answers

What should be done to the furnace when it has cooled down after an FD fan failure?

Open the FD fan damper to allow air to enter Signup and view all the answers

What should be done after repairs have been completed and the cause of the FD fan failure has been determined?

Thoroughly purge the furnace prior to beginning a normal restart Signup and view all the answers

What is the purpose of closing the FD fan damper after an FD fan failure?

To prevent combustion air from entering the furnace Signup and view all the answers

What is a common cause of flame instability in a main flame?

Excessive combustion air Signup and view all the answers

What is the primary function of the high fuel pressure cut-off switch?

To shut off the burner in case of excessive fuel pressure Signup and view all the answers

What can cause inadequate atomizing medium pressure in a main flame?

Inadequate atomizing air pressure Signup and view all the answers

What is the recommended action if the fuel oil supply pressure is low?

Clean the fuel strainer Signup and view all the answers

What is the purpose of the flame safeguard control system?

To detect and respond to flame failure Signup and view all the answers

What is a common cause of flame failure in a main flame?

Faulty flame scanners Signup and view all the answers

What is the recommended action if the fuel oil strainer is blocked?

Clean the fuel strainer Signup and view all the answers

What is the purpose of the low fuel pressure cut-off switch?

To shut off the burner in case of low fuel pressure Signup and view all the answers

What can cause excessive fuel pressure in a main flame?

Improperly adjusted fuel pressure regulator Signup and view all the answers

What is the recommended action if the flame safeguard control system fails to operate?

Contact a certified burner technician Signup and view all the answers

Study Notes

Power Plant Operations and Equipment Failures

Power plant equipment failures can occur despite best efforts, and operators must know how to respond to adverse conditions.
Operators must be well-versed in plant blackout procedures and follow them closely to ensure safe operations.

Electrical Power Failures

Electrical power failures require immediate and effective operator response.
Key considerations for operators include:
- Positions of control valves in case of failure (open, shut, or last position)
- Equipment fed by standby power and uninterruptible power sources
- Manual startup of standby generators and automatic transfer switches
- Plant load shedding strategies
- Restarting equipment after power restoration

Equipment Restart After Power Failure

Some equipment will restart automatically when power is restored, including:
- Lighting and power receptacles
- Pumps and fans that cycle on or off regularly
- Smaller air compressors and refrigeration compressors
Equipment that requires manual restart includes:
- Fuel oil pumps
- Boiler feedwater pumps
- Chilled water pumps
- Condenser water pumps
- Boiler draft fans
- Condensate transfer pumps
- Large air compressors

Valve Failure

Valves go to a fail-safe position during power failure, with some failing open and others failing shut or closed.
Self-powered regulating and control valves continue to operate in response to their set point and process variable.
Specific valve failures to be aware of:
- Heating system control valves typically fail open
- Fuel line safety shut-off valves fail closed
- Fuel line bleed valves fail open
- Boiler feedwater regulating valves fail closed (unless self-powered)

Boiler Operations and Safety

On power failure, the operator must ensure the boiler fire is extinguished and the boiler feedwater is stopped.
The main and pilot test firing valves must be closed to prevent unattended light-off when power is restored.
For boilers firing solid fuel, the operator must "bank" the fire by shutting down draft fans, closing combustion air dampers, and closing flue or stack dampers.
Banking may also involve covering the fire with green coal or ashes, or excluding oxygen by adding steam or other extinguishing medium.

Plants with No Backup Power

Plants without backup power remain "dead" until normal utility power is restored.
The operator's job is to put the plant in a safe state until power returns, involving tasks such as:
- Monitoring the boiler as it cools down
- Isolating the boiler feed pumps
- Closing the feedwater control valves
- Closing the fuel line test firing valves
- Opening the boiler non-return valve drain

Plants with Emergency Power Supply Systems (EPSS)

Plants with EPSS have backup diesel engines, natural gas engines, or gas turbines operating standby generators.
The generators are connected to automatic load transfer switches that supply power to essential loads.
EPSS are designed to supply long-term power to essential loads, such as:
- Control room panels and instrumentation
- Emergency lighting
- Feedwater control valves
- Fuel control valves
- Boiler feedwater pumps
- Condensate pumps
- Turbine seal oil pumps
- Turbine lubricating oil pumps
- Fire water pumps

Uninterruptible Power Supply (UPS)

A UPS maintains power to critical equipment through a system of batteries, rectifiers, power inverters, and automatic transfer switches.
UPS systems are designed for short-term power supply, typically up to 6 hours.
Examples of UPS-powered equipment include:
- Instrumentation and controls
- Computers
- Lighting

Feedwater System

A loss of boiler feedwater can result in a low water condition and a boiler trip.
Causes of feedwater loss include:
- Pump failure
- Control valve failure
- Failure to return condensate to the plant
The operator must take steps to restore feedwater flow, including:
- Starting the standby feedwater pump
- Checking the feedwater control valve position
- Modulating the bypass valve manually
- Repairing the feedwater control valve

Boiler Trips and Low Water Conditions

If the cause of low water cannot be determined quickly, the boiler must trip on low water.
After tripping, the pilot and main test firing valves must be shut, and the boiler must be isolated, cooled, and inspected.
If the boiler sustains a low water condition, the fires will continue to operate, and metal surfaces can overheat and weaken.
The operator must trip the boiler manually, shut the test firing valves, and isolate, cool, drain, and open up the boiler for internal inspection.### Flame Failure and Safeguard Controls
Low atomizing medium cut-off switch should extinguish the burner before flame failure occurs to prevent poor quality oil flame.
Defective or improperly adjusted switch can cause the flame safeguard control to trip the burner off.

Failure of Flame Detection and Flame Safeguard Controls

Flame scanners can fail and need replacement after 40,000 hours of operation or sooner if exposed to high temperature.
Ensure flame scanners have adequate cooling air while in service to prolong their lifespan.
Flame rods can warp and come out of alignment over time, leading to failure to detect the pilot or main flame.
Ceramic insulators can fail and short out the flame rod.
Annual maintenance is necessary to ensure flame rods are clean, ceramic insulators are intact, and they are properly aligned.

Flame Safeguard Control System Failure

Flame safeguard controls (programmed combustion controllers and primary controls) can also fail.
Defective programmed combustion control or flame amplifier may cause the boiler to fail to light off or experience repeated flame failures.
Contact a certified technician to inspect the operation of the flame safeguard control system and replace defective components.

Forced Draft Fan Failure

Forced draft fans can fail due to failure of the electric motor, fan bearing, coupling, or fan belt.
If the draft fan fails, the combustion air proving switch should open and extinguish the burner to prevent explosive conditions.
If the switch fails to operate, the flame will become excessively smoky.
In case of FD fan failure, shut down the main and pilot test firing valves, close the FD fan damper, and follow the normal boiler shutdown procedure.
Replace the combustion air proving switch, adjust according to the burner manufacturer specifications, and test prior to placing the boiler in service.
Purge the furnace prior to beginning a normal restart after repairs.

Power Plant Operations and Equipment Failures

Power plant equipment failures can occur despite best efforts, and operators must know how to respond to adverse conditions.
Operators must be well-versed in plant blackout procedures and follow them closely to ensure safe operations.

Electrical Power Failures

Electrical power failures require immediate and effective operator response.
Key considerations for operators include:
- Positions of control valves in case of failure (open, shut, or last position)
- Equipment fed by standby power and uninterruptible power sources
- Manual startup of standby generators and automatic transfer switches
- Plant load shedding strategies
- Restarting equipment after power restoration

Equipment Restart After Power Failure

Some equipment will restart automatically when power is restored, including:
- Lighting and power receptacles
- Pumps and fans that cycle on or off regularly
- Smaller air compressors and refrigeration compressors
Equipment that requires manual restart includes:
- Fuel oil pumps
- Boiler feedwater pumps
- Chilled water pumps
- Condenser water pumps
- Boiler draft fans
- Condensate transfer pumps
- Large air compressors

Valve Failure

Valves go to a fail-safe position during power failure, with some failing open and others failing shut or closed.
Self-powered regulating and control valves continue to operate in response to their set point and process variable.
Specific valve failures to be aware of:
- Heating system control valves typically fail open
- Fuel line safety shut-off valves fail closed
- Fuel line bleed valves fail open
- Boiler feedwater regulating valves fail closed (unless self-powered)

Boiler Operations and Safety

On power failure, the operator must ensure the boiler fire is extinguished and the boiler feedwater is stopped.
The main and pilot test firing valves must be closed to prevent unattended light-off when power is restored.
For boilers firing solid fuel, the operator must "bank" the fire by shutting down draft fans, closing combustion air dampers, and closing flue or stack dampers.
Banking may also involve covering the fire with green coal or ashes, or excluding oxygen by adding steam or other extinguishing medium.

Plants with No Backup Power

Plants without backup power remain "dead" until normal utility power is restored.
The operator's job is to put the plant in a safe state until power returns, involving tasks such as:
- Monitoring the boiler as it cools down
- Isolating the boiler feed pumps
- Closing the feedwater control valves
- Closing the fuel line test firing valves
- Opening the boiler non-return valve drain

Plants with Emergency Power Supply Systems (EPSS)

Plants with EPSS have backup diesel engines, natural gas engines, or gas turbines operating standby generators.
The generators are connected to automatic load transfer switches that supply power to essential loads.
EPSS are designed to supply long-term power to essential loads, such as:
- Control room panels and instrumentation
- Emergency lighting
- Feedwater control valves
- Fuel control valves
- Boiler feedwater pumps
- Condensate pumps
- Turbine seal oil pumps
- Turbine lubricating oil pumps
- Fire water pumps

Uninterruptible Power Supply (UPS)

A UPS maintains power to critical equipment through a system of batteries, rectifiers, power inverters, and automatic transfer switches.
UPS systems are designed for short-term power supply, typically up to 6 hours.
Examples of UPS-powered equipment include:
- Instrumentation and controls
- Computers
- Lighting

Feedwater System

A loss of boiler feedwater can result in a low water condition and a boiler trip.
Causes of feedwater loss include:
- Pump failure
- Control valve failure
- Failure to return condensate to the plant
The operator must take steps to restore feedwater flow, including:
- Starting the standby feedwater pump
- Checking the feedwater control valve position
- Modulating the bypass valve manually
- Repairing the feedwater control valve

Boiler Trips and Low Water Conditions

If the cause of low water cannot be determined quickly, the boiler must trip on low water.
After tripping, the pilot and main test firing valves must be shut, and the boiler must be isolated, cooled, and inspected.
If the boiler sustains a low water condition, the fires will continue to operate, and metal surfaces can overheat and weaken.
The operator must trip the boiler manually, shut the test firing valves, and isolate, cool, drain, and open up the boiler for internal inspection.### Flame Failure and Safeguard Controls
Low atomizing medium cut-off switch should extinguish the burner before flame failure occurs to prevent poor quality oil flame.
Defective or improperly adjusted switch can cause the flame safeguard control to trip the burner off.

Failure of Flame Detection and Flame Safeguard Controls

Flame scanners can fail and need replacement after 40,000 hours of operation or sooner if exposed to high temperature.
Ensure flame scanners have adequate cooling air while in service to prolong their lifespan.
Flame rods can warp and come out of alignment over time, leading to failure to detect the pilot or main flame.
Ceramic insulators can fail and short out the flame rod.
Annual maintenance is necessary to ensure flame rods are clean, ceramic insulators are intact, and they are properly aligned.

Flame Safeguard Control System Failure

Flame safeguard controls (programmed combustion controllers and primary controls) can also fail.
Defective programmed combustion control or flame amplifier may cause the boiler to fail to light off or experience repeated flame failures.
Contact a certified technician to inspect the operation of the flame safeguard control system and replace defective components.

Forced Draft Fan Failure

Forced draft fans can fail due to failure of the electric motor, fan bearing, coupling, or fan belt.
If the draft fan fails, the combustion air proving switch should open and extinguish the burner to prevent explosive conditions.
If the switch fails to operate, the flame will become excessively smoky.
In case of FD fan failure, shut down the main and pilot test firing valves, close the FD fan damper, and follow the normal boiler shutdown procedure.
Replace the combustion air proving switch, adjust according to the burner manufacturer specifications, and test prior to placing the boiler in service.
Purge the furnace prior to beginning a normal restart after repairs.

Power Plant Operations and Equipment Failures

Power plant equipment failures can occur despite best efforts, and operators must know how to respond to adverse conditions.
Operators must be well-versed in plant blackout procedures and follow them closely to ensure safe operations.

Electrical Power Failures

Electrical power failures require immediate and effective operator response.
Key considerations for operators include:
- Positions of control valves in case of failure (open, shut, or last position)
- Equipment fed by standby power and uninterruptible power sources
- Manual startup of standby generators and automatic transfer switches
- Plant load shedding strategies
- Restarting equipment after power restoration

Equipment Restart After Power Failure

Some equipment will restart automatically when power is restored, including:
- Lighting and power receptacles
- Pumps and fans that cycle on or off regularly
- Smaller air compressors and refrigeration compressors
Equipment that requires manual restart includes:
- Fuel oil pumps
- Boiler feedwater pumps
- Chilled water pumps
- Condenser water pumps
- Boiler draft fans
- Condensate transfer pumps
- Large air compressors

Valve Failure

Valves go to a fail-safe position during power failure, with some failing open and others failing shut or closed.
Self-powered regulating and control valves continue to operate in response to their set point and process variable.
Specific valve failures to be aware of:
- Heating system control valves typically fail open
- Fuel line safety shut-off valves fail closed
- Fuel line bleed valves fail open
- Boiler feedwater regulating valves fail closed (unless self-powered)

Boiler Operations and Safety

On power failure, the operator must ensure the boiler fire is extinguished and the boiler feedwater is stopped.
The main and pilot test firing valves must be closed to prevent unattended light-off when power is restored.
For boilers firing solid fuel, the operator must "bank" the fire by shutting down draft fans, closing combustion air dampers, and closing flue or stack dampers.
Banking may also involve covering the fire with green coal or ashes, or excluding oxygen by adding steam or other extinguishing medium.

Plants with No Backup Power

Plants without backup power remain "dead" until normal utility power is restored.
The operator's job is to put the plant in a safe state until power returns, involving tasks such as:
- Monitoring the boiler as it cools down
- Isolating the boiler feed pumps
- Closing the feedwater control valves
- Closing the fuel line test firing valves
- Opening the boiler non-return valve drain

Plants with Emergency Power Supply Systems (EPSS)

Plants with EPSS have backup diesel engines, natural gas engines, or gas turbines operating standby generators.
The generators are connected to automatic load transfer switches that supply power to essential loads.
EPSS are designed to supply long-term power to essential loads, such as:
- Control room panels and instrumentation
- Emergency lighting
- Feedwater control valves
- Fuel control valves
- Boiler feedwater pumps
- Condensate pumps
- Turbine seal oil pumps
- Turbine lubricating oil pumps
- Fire water pumps

Uninterruptible Power Supply (UPS)

A UPS maintains power to critical equipment through a system of batteries, rectifiers, power inverters, and automatic transfer switches.
UPS systems are designed for short-term power supply, typically up to 6 hours.
Examples of UPS-powered equipment include:
- Instrumentation and controls
- Computers
- Lighting

Feedwater System

A loss of boiler feedwater can result in a low water condition and a boiler trip.
Causes of feedwater loss include:
- Pump failure
- Control valve failure
- Failure to return condensate to the plant
The operator must take steps to restore feedwater flow, including:
- Starting the standby feedwater pump
- Checking the feedwater control valve position
- Modulating the bypass valve manually
- Repairing the feedwater control valve

Boiler Trips and Low Water Conditions

If the cause of low water cannot be determined quickly, the boiler must trip on low water.
After tripping, the pilot and main test firing valves must be shut, and the boiler must be isolated, cooled, and inspected.
If the boiler sustains a low water condition, the fires will continue to operate, and metal surfaces can overheat and weaken.
The operator must trip the boiler manually, shut the test firing valves, and isolate, cool, drain, and open up the boiler for internal inspection.### Flame Failure and Safeguard Controls
Low atomizing medium cut-off switch should extinguish the burner before flame failure occurs to prevent poor quality oil flame.
Defective or improperly adjusted switch can cause the flame safeguard control to trip the burner off.

Failure of Flame Detection and Flame Safeguard Controls

Flame scanners can fail and need replacement after 40,000 hours of operation or sooner if exposed to high temperature.
Ensure flame scanners have adequate cooling air while in service to prolong their lifespan.
Flame rods can warp and come out of alignment over time, leading to failure to detect the pilot or main flame.
Ceramic insulators can fail and short out the flame rod.
Annual maintenance is necessary to ensure flame rods are clean, ceramic insulators are intact, and they are properly aligned.

Flame Safeguard Control System Failure

Flame safeguard controls (programmed combustion controllers and primary controls) can also fail.
Defective programmed combustion control or flame amplifier may cause the boiler to fail to light off or experience repeated flame failures.
Contact a certified technician to inspect the operation of the flame safeguard control system and replace defective components.

Forced Draft Fan Failure

Forced draft fans can fail due to failure of the electric motor, fan bearing, coupling, or fan belt.
If the draft fan fails, the combustion air proving switch should open and extinguish the burner to prevent explosive conditions.
If the switch fails to operate, the flame will become excessively smoky.
In case of FD fan failure, shut down the main and pilot test firing valves, close the FD fan damper, and follow the normal boiler shutdown procedure.
Replace the combustion air proving switch, adjust according to the burner manufacturer specifications, and test prior to placing the boiler in service.
Purge the furnace prior to beginning a normal restart after repairs.

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Description

This quiz covers common equipment failures in power plants and the general principles for responding to adverse conditions. It's essential for Power Engineers to know and practice these procedures to respond correctly in emergency situations.