FM Techie

Equalization Tank The sewage from the bar screen chamber and oil, grease and grit trap comes to the equalization tank. The equalization tank is the first collection tank in an STP. Its main function is to act as buffer:  To collect the incoming raw sewage that comes at widely fluctuating rates, and pass it on to the rest of the STP at a steady (average) flow rate. During the peak hours, sewage comes at a high rate. The equalization tank stores this sewage, and lets it out during the non-peak time when there is no/little incoming sewage. 1 The inlet pipe  2 The sewage is collected in the tank.  3 The raw sewage lift pumps 4 The delivery pipe takes the sewage to the aeration tank. 5 The coarse bubble diffusers are short length of tubes that have holes at regular spacing. They release large bubbles in the tank to lightly aerate the sewage, and also to agitate the mix continuously. 6 Compressed air comes though this air supply pipeline.  Operation And Maintenance Conside...

Procedure for Breakdown test: 1) 3 to 4 litres of oil needs to be let out before collecting the oil sample.  2) oil sample from Transformer before filtration. 3) The gap between the test electrodes must be 2.5mm.  4) The oil can withstand 40kV for a minute if it is having good dielectric strength. Voltage should be gradually increased from zero.  5) At one point Flash will take place and that point is termed as Bread down Voltage In Oil filtration process, the oil passes through three chambers in the oil filter. They are 1.Paper Filter, 2.Heater, 3.Vacuum Chamber Paper Filter removes carbon particles from the oil. Heater & Vacuum Chamber removes moisture content from the oil. Mainly transformer oil is used for insulation purpose.  When the oil contacts with atmospheric air in the conservator, the air moisturize the oil and reduce its dielectric strength.  So, the transformer oil should be filtered once in a year. This process should repeat at least for 6 to ...

Daily Transformer Inspection Checklist Regular inspection of transformers is essential for their efficient operation and long life. Below is a simple checklist for daily transformer inspection to ensure safety and performance. 1. Check and Record Winding Temperature Monitor the winding temperature and note it down. Abnormal temperature rise may indicate a fault. 2. Check and Record Oil Temperature Measure and record the oil temperature. Overheating of oil can reduce its insulating properties. 3. Check Conservator Tank Oil Level Ensure the oil level in the conservator tank is adequate. A low level may indicate leakage or oil degradation. 4. Check for Oil Leakages Inspect the transformer for any visible oil leaks, which can lead to serious operational issues. 5. Check the Colour of Silica Gel The silica gel in the breather should be pale blue. If it turns pink or white, it needs to be replaced as it has absorbed moisture. 6. Check the Explosion Vent Diaphragm Inspect the explosion vent d...

BAR SCREEN CHAMBER The function of the bar screen is to prevent entry of solid particles above a certain size; such as plastic cups, paper dishes, polythene bags into the STP.  The screening is achieved by placing a screen made out of vertical bars, placed across the sewage flow. The gaps between the bars may vary between 10 and 25 mm. Larger STPs may have two screens: A coarse bar screen with larger gaps between bars, followed by a fine bar screen with smaller gaps between bars.  In smaller STPs, a single fine bar screen may be adequate.  1 Inlet pipe for the STP. 2 Debris  3 Muck accumulates  4 Grill. Must be cleaned regularly to avoid a build-up of debris (2) and muck (3). 5 Screened sewage.  6 Outlet pipe (goes to the Equalization Tank) 7 Platform with weep holes. The STP operator stands here to rake the debris (2). Operation And Maintenance Considerations Check and clean the bar screen at frequent intervals Do not allow solids to overflow/ escape from ...

Sewage treatment is a crucial process that removes contaminants from wastewater, household sewage, and effluents. It involves physical, chemical, and biological methods to ensure that the treated water is safe for disposal or reuse. Proper sewage treatment helps protect the environment and reduces the demand for portable water in buildings. Stages of Sewage Treatment Sewage treatment typically involves three main stages: primary, secondary, and tertiary treatment. 1. Primary Treatment (Solid Separation) Large solid particles and sediments are separated from the wastewater. The solids settle at the bottom, while lighter materials like oils and grease float and are removed. 2. Secondary Treatment (Biological Process) The remaining wastewater contains dissolved organic matter. This is broken down using water-borne microorganisms that convert waste into a solid mass. The biological solids are then neutralized and either disposed of or reused. 3. Tertiary Treatment (Final Purification &...

Causes of Faults in Transformers Transformers are critical components in electrical power systems, and their failure can lead to significant operational disruptions. Various factors contribute to transformer faults, which can be classified based on their origin and impact. Here are some of the most common causes of transformer faults:   1. Winding to Core Faults (Insulation Failure) One of the most common transformer faults occurs due to weakening of insulation between the winding and core. Over time, insulation deteriorates due to aging, overheating, or moisture, leading to short circuits. Key Points: Phase to phase faults inside transformers are rare. Faults may occur at terminals, which are within the transformer protection zone. 2. On Load Tap Changer (OLTC) Faults Power transformers are often equipped with an On Load Tap Changer (OLTC) to regulate voltage levels. This component is prone to mechanical failures, contact wear, or improper operation, leading to transformer faults....