Lp Bypass unit

         Having learnt about the importance of Hpbypass unit in the last post. Today let us know the importance of the LPBypass unit. Lpbypass unit bypasses the reheated steam from entering into the IP turbine by bypassing the steam directly into the condenser. Like HPBypass it also has main control valve, spray control valve and oil supply unit. Along with these it also has Isolation valve or stop valve which is not present in the HPBypass system as the Emergency stop valve serves the purpose in the HPBypass system.

       The LPBypass unit is important during the shutdown and the startup of the thermal power plant. Steam from the Hpbypass system eneters the CRH line and gets reheated in the boiler section and gets back to turbnie which is bypassed by the LPBypass unit directly into the condenser. Unlike HPBypass we must take much care in the LPbypass unit as the steam is directly sent to condenser the condenser wall temperatures will raise and the spray control valves must operate properly and timely manner to save the condenser if this is not maintained the system will stop the steam from entering to condenser by closing the stop valves to protect the condenser.

       The lbbypass valves cannot be opened directly during the cold startup as the temperature of the valves and the steam do not match and may result in the line hammering. So initially the lpbypass line is warmed up through warmup lines and they remain until the lpbypass lines has sufficient temperatures. 

       Here the LPBypass oil unit is used to supply the oil to the control valves and stop valves for proper operation.

 Thanks all

Important days to remember

Hi all,

January :-

January 1 - Global Family Day, Army Medical Corps Establishment Day

January 6 - World War Orphans Day

January 9 - NRI Day or Pravasi Bhartiya Diwas

January 10 - World Laughter Day

January 11 - Death anniversary of Lal Bahadur Shastri

January 12 - National Youth Day or Birthday of Swami Vivekananda

January 15 - National Army Day

January 23 - Netaji Subhash Chandra Bose's Birth Anniversary

January 24 - National Girl Child Day of India

January 25 - National Tourism Day, National Voters Day

January 26 - Republic Day of India, International Customs duty day

January 27 - International Holocaust Remembrance Day

January 28 - Birth Anniversary of Lala Lajpat Rai

January 30 - National Martyr’s Day or Sarvodaya Day,World Leprosy Eradication Day



February :-

February 2 - World Wetlands Day

February 4 - World Cancer Day

2nd Sunday of February - World Marriage Day

February 6 - International Day against Female Genital Mutilation

February 11 - World Day of the Sick

February 12 - Darwin Day

February 13 - World Radio Day, National womens day or Sarojini Naydu’s Birthday

February 14 - Valantine's Day

February 20 - World Day of Social Justice

February 21 - International Mother Language Day

February 22 - World Scout Day, World Thinking day

February 23 - World Peace and Understanding Day

February 24 - Central Excise Day

February 28 - National Science Day



March :-

March 3 - National Defence Day

March 4 - National Security Day

March 8 - International Womens’ Day

2nd Monday of March - Commonwealth Day

March 15 - World Consumer Rights Day, United Nations' International Day of Persons with            Disabilities

March 16 - National Vaccination Day

March 18 - National Ordinance Factories Day

March 20 - International Day of Happiness, World sparrow day

March 21 - World Forestry Day, International Day for the Elimination of Racial

           Discrimination, World Poetry Day

March 22 - World Water Day

March 23 - World Meteorological Day

March 24 - World TB Day, International Day for Achievers

March 25 - International Day of Remembrance – Victims of Slavery and Transatlantic Slave

Trade

March 26 - World Purple day(epilepsy awareness day)

March 27 - World Drama Day or World Theater Day



April  :-

April 1 - April fool's day

April 4 - International Day for Mine Awareness and Assistance in Mine Action

April 5 - National Maritime Day

April 7 - World Health Day

April 12 - World Aviation & Cosmonauts Day

April 14 - B.R.Ambedkar Remembrance Day

April 15 - World day of Silence.

April 17 - World Haemophilia Day

April 18 - World Heritage Day

April 21 - World Creativity and Innovation Day, National Civil Services Day

April 22 - World Earth Day

April 25 - World Malaria Day

April 26 - World Intellectual Property Day

April 28 - International Worker’s Memorial Day, World day for Safety and Health at work

April 29 - World Dance Day



May :-

May 01 - World Labour Day or May Day or Workers Day

May 03 - Press Freedom Day(Intl.), International Sun Day, World Asthma Day

May 04 - Coal Miners Day(Intl.), International Firefighters’ Day

1st Sunday of May - World Laughter Day

May 05 - World Athletics Day.

May 06 - World No Diet Day

May 08 - World Red Cross Day or Red Crescent Day, Remembrance and Reconciliation for Lost

Lives of Second World War

2nd sunday of May - World Mother Day

May 10 - International Migratory Bird Day

May 11 - National technology day

May 12 - International Nurses Day

May 13 - International Criminal Court Day

May 15 - International Day of the Families

May 17 - World Tele-communication and Information Society Day, Wold AIDS Vaccination

day,World Hypertension Day, International day against Homophobia and Transphobia

May 18 - World Museum Day

May 20 - World Meteorology Day

May 21 - National Anti Terrorism Day, National Day for Cultural Development

May 22 - International Day for Biological Diversity

May 25 - International Missing Childrens day

May 29 - International Day of Peacekeepers

May 31 - World No Tobacco Day



June :-

June 1 - Global Day of Parents

June 4 - World Day of Innocent Children Victims of Aggression

June 5 - World Environment Day

June 8 - World Brain Tumor Day, World Oceans Day

June 12 - World Day Against Child Labor

June 14 - World Blood Donor Day

June 15 - World elder abuse awareness day

3rd Sunday of June - World Father’s Day

June 16 - International Integration Day

June 18 - International Picnic Day

June 20 - World Refugee Day

June 21 - world yoga day and World Music Day

June 23 - International Olympic Day, United Nations Public Service Day, International Widows

Day

June 26 - International Day against Drug abuse and Illicit Trafficking, International Day in

support of Victims of torture



July :-

July 1 - International Joke Day, world Doctor’s Day

July 2 - World Sports Journalists Day, World UFO day

1st Saturday of July - International Day of Cooperatives

July 04 - America Indipendence Day

July 06 - World Zoonoses Day

JUly 07 - world forgiveness day

July 11 - World Population Day

July 12 - International Malala Day

July 18 - International Nelson Mandela Day

July 26 - Kargil Vijay Diwas or Kargil Memorial Day or Kargil Victory Day

July 28 - World Nature Conservation Day, World Hepatitis Day

July 29 - International Tiger Day



August :-

First Sunday in August - International Friendship Day

August 6 - Hiroshima Day, Anti Nuclear Day

August 8 - World Senior Citizen Day

August 9 - Nagasaki Day, International Day of the World’s Indigenous People, Quit India Day

August 12 - International Youth Day

August 13 - International Left Handers Day

August 15 - India’s Independence Day.

August 19 - World Humanitarian Day, World Photography Day

August 20 - National Sadbhavna Divas or Birthday of Rajiv gandhi, World Mosquito Day.

August 21 - National Senior Citizen Day

August 23 - International Day for the Remembrance of the Slave Trade and Its Abolition

August 29 - National Sports Day or Dhyanchand's Birthday

August 30 - International day of the victims of enforced Disappearances



September :-

September 2 - World Coconut Day

September 5 - National Teacher’s Day or Dr. Radhakrishanan's Birth Day, Sanskrit Day


September 8 - World Literacy Day

September 10 - World Anti-Suicide Day

September 14 - Hindi Diwas or Hindi Day, World First Aid Day

September 15 - International Day of Democracy, International Engineer’s Day

September 16 - World Ozone Day

September 20 - RPF Foundation day

September 21 - World Peace Day or International day for Peace and Non-violence (UN), World

Alzheimer’s Day

September 22 - World Cancer Free Day or Rose Day

September 23 - International Day of the Deaf

September 26 - World Contraception Day, european day of languages

September 27 - World Tourism Day

September 28 - World Rabies Day

September 29 - World Heart Day



October :-

1st Monday of October - World Habitat Day

October 1 - World Vegetarian Day, International Day of the older/Elderly

October 2 - Gandhi Jayanti, International Day of Non-Violence

October 3 - World Nature Day

October 4 - World Animal Day

October 5 - World Teacher’s Day

October 6 - World Wildlife Day

October 8 - Indian Air Force Day

October 9 - World Postal or Post-office Day

October 10 - World Mental Health Day, National Post-office Day

October 11 - International Day of the Girl Child

2nd Thursday of October - World Sight Day

October 12 - World Arthritis Day

October 13 - International Day for Natural Disaster Reduction

October 14 - World Standards Day

October 15 - Global Hand Washing Day, International Day of Rural Women, World White Cane

Safety Day

October 16 - World Food Day

October 17 - International Poverty Day for it's Eradication

October 20 - World Osteoporosis Day,World Statistics Day, National Solidarity day

October 24 - UN Day, World Development Information Day, World Polio Day

October 27 - World day for Audio Visual Heritage

October 28 - International Animation Day

October 31 - World Savings Day or wold Thrift day, Halloween Day
         and Rashtriya Ekta Diwas (National Unity Day) INDIA



November :-

November 1 - World Vegan Day

November 6 - International Day for Preventing the Exploitation of the Environment in War and

Armed Conflict

November 7 - Infant Protection Day, World Cancer Awareness Day

November 8 - World Radiology Day

November 9 - World Legal Service Day

November 10 - World Science day for Peace and Development, Public Transport Day

November 11 - National Education Day

November 12 - World Pneumonia Day, Public Service Broadcasting Day

November 13 - World Kindness Day

November 14 - Children’s Day(India), World Diabetes Day

November 16 - International Day for Endurance or Tolerance

November 17 - International Students Day, Gurunanak Dev's Birth Anniversary, National

eplilepsy day

November 19 - World Toilet Day, International Men’s Day, National Integration Day

November 20 - Universal Children’s Day

3rd Sunday of November - World Day of Remembrance for Road Traffic Victims

3rd Thursday of November - World Philosophy Day

November 21 - World Fisheries Day, World Hello Day, World Television Day

November 25 - International Day for the Elimination of Violence Against Women, World Non-Veg

day

November 26 - National Law Day or National constitution Day

November 30 - National Flag Day



December :-

December 1 - World AIDS Day

December 2 - World Computer Literacy Day, International Day for the Abolition of Slavery

December 3 - International Day of People with Disability or World Disability Day

December 4 - Indian Navy Day

December 5 - International Volunteer Day for Economic and Social Development

December 7 - International Civil Aviation Day, Indian Armed Force Flag Day

December 9 - The International Anti-Corruption Day

December 10 - World Human Rights Day,International Children's Day of Broadcasting

December 11 - International Mountain Day, UNICEF Day

December 14 - National Energy Conservation Day(India)

December 16 - Vijay Diwas

December 18 - International Migrants Day, National Minority Rights Day

December 19 - Goa’s Liberation Day

December 20 - International Human Solidarity Day

December 23 - National Farmer’s Day or Kisan Diwas

 Thanks all

GENERAL COMPLAINTS FOR C&I in a thermal power plant

                Common C&I issues in a thermal power plant and few case studies , first thing when a problem arises due to signal problem but physically everything is fine, which can shut the unit then first return to normalcy then troubleshoot

1) Cable of instruments may be damaged.

2) Improper connectivity in the Juntion box.

3) Termination problems at the field element.

4) Feedback may be got disturbed due to vibrations.

5) Element setting may be varied need to be adjusted.

6) Element itself be damaged, need to have stock and replace it.

7) Communication network may be damaged.

8) Card may get failed.

9) Card slot may be damaged and not able to supply enough voltage or current

10) Communication cable problem due to cuts.

11) In a loop a single element may cause system to halt need to verify for that element.

12) Due to latching issues in the instruments.

13) Internal logic may got modified.

Case study 1 :

The thermal plant was successfully running for three months and one day in the spray station of the feed water cycle, the control valve present in the actuator was settled to a position and is not responding, the feeding to deaerator is decreased and the level started to fall down.

Solution:

It was found that the manual command to increment the position of the control valve is blocked, first this condition is bypassed and normalcy is restored, later when started troubleshooting it was found that the condition occurred due to the CEP ( Condensate extraction pump) common discharge pressure transmitter value reduced by half that internally is related to the increment condition. As the value is below the set point provided the valve increment is blocked. When verified at the transmitter,  local reading is found to be fine. Then the channel in the card present in the DCS side is changed and now  the value is normalised.

Case study 2 :

The hpbypass valves are opened due to high pressure maintained and the valves opened and closed and during this time the spray valves also got opened and closed but still the temperature kept on raising and the spray valve did not open in auto mode on temperature limit

Solution :

Physically ensured if there is any passage in the hpbypass valve and found the valve to be almost full closed. Then took the spray valves into manual mode from auto and tried to open the valve but still the valve is not opened. Checked for the logic and found the increment option is blocked, bypassed the condition and opened the spray valves and the normalcy is restored. Later checked for condition and found the spray valve did not open as the condition to open has position feedback of hpbypass main valve to be greater than certain value, as the valve is fully closed and the feedback position is less than that set point valve did not open.

case study 3:

Suddenly there is rise in the feed water flow and the level of drum started to increase very fast and there is no manual intervention and the Hpbypass valve is fully closed.

Solution: 

As the hpbypass valve is fully closed, first isolated the hpbypass flow condition from the feedwater loop by making its value zero. Then went to the location, the flows are generally calculated using the Differential pressure transmitter (DP) , found out that there is a leak in impulse line of the DP transmitter beause of which there is high pressure maintained on one side and low pressure on the other which transmitter assumed to be flow and raised the feedwater flow. Closed both the impulse line and rectified the leak and working fine.

Case study 4:
LP bypass oil pumps are put off  due to leakage of oil.

Solution :
This is one of the important condition and need to act as fast as possible. If oil is not available then the pump cannot supply oil to valve and if necessity arises. Make sure the oil is leakage is arrested and fill the oil in the tank. Then get the pump started and wait until sufficient oil pressure is developed and then put the pump in service. If oil pressure is not sufficient then the Lpbypass valve operation will be slow.

Case study 5:
Primary water tank level found to be faulty and varying.

Solution:
The primary water level value of the tank is not an interruption for the operation of the plant until there physically exists the level of water in the tank. But due to variation of the level transmitter value there will  not be surety in the physical level and always need to check the value. Checked at the transmitter side the cable is found to be healthy, No loose contact of cables found at transmitter or DCS (Distributed control system) side. Then checked at the sensor and transmitter contact there seems to be minute disturbance in the adjustment between then. aligned it properly then it seems fine.

Case study 6 :

Vaccum suddenly getting dropped?

Solution :

A thermal power plant suddenly gets tripped if proper vaccum is not maintained because the steam will condense in the turbine and results in deformation if proper vaccum is not maintained.

1) Once there was sudden vacuum drop happened and first of all restore normalcy, the drop occurred due to seal steam supply was cutoff, first the seal steam supply was restored and the normalcy retained, later when found out, an RTD present in the leakoff loop was checked below a certain value and the leakoff valve of seal seam fully opened and seal steam was cutoff. Later it was checked and rectified. As it is of less importance u can also bypass this condition

2) If any valve at the vacuum pumps side is opened and is open to air, the unit gets tripped off make sure vaccum pump valves are closed.

Case study 7:

Vaccum transmitter showing the wrong value during the running condition but normal during the shutdown

solution:

A vaccum transmitter during the normal working condition of the plant seems to deviate from the normal value but when try to attend the complaint during the shutdown condition, the value seems to be normal along with the other vaccum transmitters. This happened for around six to 7 months and the condition persists. Later changed the root valve after which the transmitter is connected in the pipe. It worked for few hours, again the same problem persisted. Later changed the transmitter point to another spare location and the value seems to be fine,concluded that the problem exists in the impulse line and not in the transmitter. It is suspected to be line choke.

Case study 8:

The four temperature control valves in turbine stopped working.

Solution:

In turbine are there will be four temperature control valve namely primary water, main oil tank, control fluid, cold gas temperature control valves. All these control valves stopped operating these occurred due to failure of relay in getting the supply and there should be a second source but it did not happen and that was due to electric breaker trip. After replacing the relay and restoring the electrical supply still the valves are not operating due to the fuse blown off. Replaced the fuses and changed the TB where loose contacts are present and all valves started working.