Hydropower
Hydropower system used mechanical energy of water and converting to Electrical energy by using Kaplan ,Francis turbine.Turbine rotates the generator shaft and due to mutual induction produced Electrical energy without any garbage and pollution. Hydro Power is also friendly Source of electricity.
Hydro Electric Power (Hydel Power )
When the blades of turbines is turned and water flow through the turbine which is connected by shaft of the generator then hydro-electric power is generated
Complete mechanism of Hydro Power(turbine coupled with generator)
The efficiency of the plant can be calculated by following formula.
Among of all the Induction generator is batter w.r.t. others but with poor voltage regulation. Voltage regulation is improved simply by using governors in parallel to the actual load.
Lots of energy in the water no one bears the water energy (in flood season). A human can use this energy for his benefits to building the hydro plant. In the hydro plant energy of water enhance which depends upon two factors.
Operational Improvements:
Electricity Market Opportunities:
The method of Energy Extraction from Water:
Energy from water sources:
It is the cheap and reliable way to collect the energy from moving water and produced electricity. Waves produced in the sea due to an interaction of the wind with the sea water can be said energy in the wind move toward the water. When the wave moves faster and high usually completed the moon or in faster wind blow then these tides of water collect in the reservoir and cross these water in the tunnel to move the prime mover of Generator.
Micro- Mini Hydro power:
Hydro power energy is one of the best renewable sources of energy. The energy from water source can be extracted from the dam. Dams are small or large in size. From the research study, small dams are more beneficial than the large because no of problems faces in the large dam are more than the small. Men used water sources when lived in caves and hills. They used water to move their machine to grind the wheat stone. Small power plant fulfills the needs of rural areas of nearby. Large dam required a lot of reservoir of water and a lot amount of water but instead small Hydro power not required enough water. We can install smaller project in place of single large power project of Hydro.
Energy from the sea - Ocean thermal, tidal and wave energy:
We know the 71% water exist on the earth and 29 % are other things like hills, Forest, and deserts. It mean a large amount of heat from the sun observe the sea and oceans. What happens when we sue these amount of heat directly from the sea or oceans? From this energy, we can generate the Mega Watts of electricity. On this idea, most of the brilliant minds work on it in this phenomena a heat engine design which operates form the temperature difference on the surface of the sea and the 100-meter depth. This technology knows as the OTEC which is the abbreviation of Ocean Thermal energy conversion.
Main component:
There are following like Dam, Reservoir, Large buffer tank, Penstock and Power houses are the main component of the Hydro Electric generation. In the Powerhouse Turbines, Generators, Step Up Transformer and different complicated circuits for protection and safety of high power generators are used.
Categories: Large Hydel Plant:
50MW to 1000 MW(Large Cities)
Small Hydel Plant:
1 MW to 50MW (Small Cities)
Mini Hydel Plant:
100kW to 1000KW(Towns)
Micro Hydel Plant:
< 100kW(Rural Community)
Pico Hydel Plant:
<5KW (Individual Home)
Efficiency:
The efficiency of the plant can be calculated by following formula.
Power _ Delivered = 7. H. dQ/DT = Kilowatts
H = head in meter
DQ/DT = rate of discharge in m3/sNormally hydel plant efficiency id about 75%.
Types of Generator:
Permanent magnet DC generator (PMDC) Alternator (Synchronous Generator) Induction Generator Synchronous reluctance Generator
There is the following important point: Sinusoidal outputGood voltage regulationRugged and easy to maintainSimple to fabricateHigh efficiency Cost effective for given powerEase of servicing/operationSafetyReliability
Which one is Best:
Among of all the Induction generator is batter w.r.t. others but with poor voltage regulation. Voltage regulation is improved simply by using governors in parallel to the actual load.
Water energy:
Lots of energy in the water no one bears the water energy (in flood season). A human can use this energy for his benefits to building the hydro plant. In the hydro plant energy of water enhance which depends upon two factors.
Head
Flow
The head is vertically high and large to increase the flow of water through turbine for maximumoutput.
The flow is the amount of water that flows in one second.
The flow is the amount of water that flows in one second.
Energy = m.g.h
weight water = Kggravity = 9.81 m/s2
height = meter
Energy = ρ. Q. g. h joules
ρ = density of water = Kg/m3
Q = discharge = m3
g = acceleration due to gravity = 9.81 m/s2
h = height = meter
Q = discharge = m3
g = acceleration due to gravity = 9.81 m/s2
h = height = meter
Power = ρ. dq/dt. g. h joules
ρ = density of water = Kg/m3
dq/dt = m3/s
g(earth) = = 9.81 m/s2
1 KilowattHour = 1000watts x 3600 seconds = 3.6e6
watt-second = 3.6e6 Joules
1 m3 = 1000 liters
Let the efficiency of hydro power is 70 to 75%.
dq/dt = m3/s
g(earth) = = 9.81 m/s2
1 KilowattHour = 1000watts x 3600 seconds = 3.6e6
watt-second = 3.6e6 Joules
1 m3 = 1000 liters
Let the efficiency of hydro power is 70 to 75%.
Power _ Delivered = 7. H. dQ/DT = Kilo watts
h = Head in meters
dQ/dt = Rate of discharge in m3/s.
dQ/dt = Rate of discharge in m3/s.
Turbine:
Turbine is one of the most important parts for generating the electricity from hydro power. Its like a machine that converts the potential energy of water into the mechanical energy. As the time pass, different types of the turbine are formed for different criteria.
Impulse turbines for high heads Reaction turbines for low heads.
Submersible propeller turbines.
Some of the turbines are Elton, crossflow, turbo, Francis, Harris
etc.
Some of the turbines are Elton, crossflow, turbo, Francis, Harris
etc.
Generator:
Induction and synchronous generators are used in the power houses to generate electricity. Induction generators are more reliable for far areas. The 3 phase induction motor can be used as a generator.
In some application, the use of the synchronous and dc generator are very pro-motive.
Load Control:
Control the load is one of the most and complicated phenomena e.g when load increase suddenly effect the generator and the vibration of the shaft of the generator increase more chances to break the baring of the turbine which is to expensive. We control the load or fill full the demand the require load by increase the water flow from wicket gates and change the angle of fans of the turbine. The opening of wicket gates and changing of fan’s angle controlled by governor with the most efficient combination.
In the power, houses deal with MW power so the controlling of a load is done by most complicated electronic circuit’s and monitored by experts.
Changing of load mean disturb the speed which also effects the voltage and frequency.
Small scale Hydro power:
The small hydroelectric system can produce power rating up to a few mage watt there are two version of hydroelectric system diversion type and reservoir type. The reservoir type may require a small dam to store water at higher elevation. The diversion type does not require a dam, depend upon the speed of the current to generate electricity.
Diversion type Hydropower:
This type of system does not require a dam so it considers more environmentally sensitive.the river for this small hydroelectric system must have stronger enough current for a realistic current generation the KE entering the turbine KE is given by
KE = .5* mv2 = .5Aspv3t
Pt = Ket/t = .5Aspv3t
Reservoir Type hydropower:
it is either a natural lake at high elevation, then a downstream river or lake created by dam. The system consist mainly a pen-stock, a turbine and generator. If the water is allowed to flow to lower elevation through the pen stock the potential energy of water converted into KE where some of it is captured by the turbine.
the PE of the water behind the reservoir PE can be found from
Per WH = mgH
the PE of the water behind the reservoir PE can be found from
Per WH = mgH
Where
W = the weight of the water, Kg
H = the elevation of the water with respect to the turbine, m;
m = the water mass of the reservoir, kg;
g = the gravitational speed, m/s
if m (kg) is mass of the water of the water entering the pen-stock can be applied to find the input PE of the pen-stock as given by
PE pin = mg
The water flow fw inside the pen-stock is defined as the mass of the water m passing through the pen stock during a time travel t that,
Fw = m/t
PE pin = fw tghH
Which is converted into KE inside the pen-stock. The output of KE can be found
KE(out) = .5Apvt pv2
Where
T= the duration of water flow, S;
V = the speed of water exiting the pen-stock,m/s;
Ap = the cross section area of penstock m2
Due to losses in side the penstock such as the water friction, the KE existing the pen-stock KE(output) o\is less then the PE(p_in) at the entrance of the penstock. Thus the efficiency of the penstock is given by
Efficiency = KE/ PEp-in
The blades of the turbine cannot capture all the kinitaic energy KE existing the penstock.
Cp = KEblade/ KEp-out
Turbine Efficiency:
The energy captured by the blade KE is not all captured in to the mechanical energy entering the generator KE due to various losses in the turbine. The ratio of two energies is know as turbine efficiency
The output electrical energy of the generator Eg its equal to its KEm minus the loss of the generator. Thus the generator efficiency ng is defined as
Generator efficiency = Eg/ KEm
The out put electrical energy as a function of water flow and head.
Eg = fGHt(Cp np nt ng)
Method Of Improvement Hydro Energy:
In the recent past two valuable organization department of energy and the research Institute of Electric Power work on the significant and improvement of hydro power approximately conclude his search in 3 years. According to the report in 2012 approximately 72giga watts of hydro energy plant were installed and generation of these hydro plant in 2012 were 279.45 KWH. It’s about seven percent of installed renewable sources in United States America.The conclusion of this report shown that there are 3 things keep in mind to improve the Hydro Energy sector which is following.
Operational Improvements:
We all know very well the technology increase for the ease and enhance the liability of system that’s directly increase the output. Mostly Power plants are in operation last 10 to 20 years and the point is that’s time the technology was not developed enough like that. So we have to change the older technology or upgrade the older with more and most efficient technology. By improving the new technology we can increase the 2-3% of generation.
Now the according to the trend the use of thermal power plants minimize because it generate population with electricity now the water is used in nuclear power plants.
New Technologies:
According to the reported income of the plant increase the 61 percent by changing its mechanical part and technology like by increase the range of operation which means that change in using tech that support at lower load and the when at peak. By this changing the plants works batter and run at the different speed according to the situation which increases the income of plant 85 %.
Electricity Market Opportunities:
Positive Changing are always for betterment so when the performance of plant increase directly electricity generation increase from the hydro power plant.
When the maintenance cost of plant decrease and generation of power plant also increase at the same input then the availability of electricity and prices of electricity also decrease. The notes of the report shown prices decrease 5 percent.
End.
The Sample analysis of a Transformer oil is very helpful and predictive to analyze the present condition or health of Transformer .Different gases are formed during normal operation in all transformers and to find the quality of certain key gases ratio then it is easy for operator to predict the issues which is rise in the transformer. Dissolved gas analysis (DGA) is perform of the insulating oil and this analysis help to predict the health of a transformer. Due to some faults inside the transformer generate the gases .These gases generates misbehaver of electrical insulating material and the components that’s relate them. It is very important to verify the identity of these gases to prevent the maintenance problem of transformer.
End.
Formation of Gases in Transformer's.
The Sample analysis of a Transformer oil is very helpful and predictive to analyze the present condition or health of Transformer .Different gases are formed during normal operation in all transformers and to find the quality of certain key gases ratio then it is easy for operator to predict the issues which is rise in the transformer. Dissolved gas analysis (DGA) is perform of the insulating oil and this analysis help to predict the health of a transformer. Due to some faults inside the transformer generate the gases .These gases generates misbehaver of electrical insulating material and the components that’s relate them. It is very important to verify the identity of these gases to prevent the maintenance problem of transformer.
The advantages of fault gas analyses
· Advance warning of developing faults
· Determining the improper use of units
· Convenient scheduling of repairs
Monitoring of units under overload
Why we analyze the Dissolved Gases
A Doctor analyze the blood of patients to predict the disease and this analysis help the doctor to give him right medicine. In the same way the owner of Transformer analyze the dissolved gases in the dielectric fluid to find the problems in the transformer. Corona discharge, arcing in the transformer, localized overheating and general overheating are the major problems in the transformer. Generated gases are dissolved in transformer insulating oil to find the problem it is necessary to find the rate of generated gas and the total amount of key gas present in the transformer. If we find the composition of generated gas then we easily find the source of generated key gas and what kind of insulation is involved.
· Combustible gas generation theory of transformer.
· Gas Analysis interpretation.
· Suggested operating procedures.
· Dornenberg ratios, and Rogers ratios are diagnostic technique for key gases.
Limitations:
A number of techniques are in market to find and measure the gases in the transformer. But it is important to note that the detection and measurement of these gases not a science but an art. To find the presence and significance of gas its totally depend upon on the qualities of the measuring instrument like that the brand, geometry, degree of saturation of various gases in the oil and a number of more qualities.
Different method to Analyze to Combustible Gases in DGA Transformer oil Testing
Evaluation of Transformer Condition Using Individual and TDCG Concentrations:
Condition 1
Condition 2
Condition 3
Evaluation of Possible Faults by the Key Gas Method
Fault Type: Thermal decomposition of Beta Fluid
Fault Type: Thermal decomposition of Cellulose
Fault Type: Corona –partial discharge:
Fault Type: Arcing
The things which is separate between Dissolve Gas Analysis(DGA) with Mineral Oil & with Beta Fluid.
Gas Solubility:
In the given below table it is shown that the solubility of different gases in beta fluid is approximately is same as the conventional transformer oil. It is usually seen that the difference between two fluids is less than 10 percent, which is often due to some poor analysis method and error in the extraction. Now the actually mean is that we can apply same techniques because the gases generated in the transformer oil also solved in the beta fluid at the same extent as that they are in mineral oil. To find the problem it is necessary to find the rate of generated gas and the total amount of key gas present in the transformer. If we find the composition of generated gas then we easily find the source of
generated key gas and what kind of insulation is involved.
There are a number of techniques to identify those gases. But the most famous ,reliable and effective method is DGA .In this method first of all we sampling the oil then test these samples to measure the amount of concentration of dissolved gases. It is important to perform DGA of transformer every year and the other important is relate previous results and this will help to predict the problems in the transformer.
ASTM D3613, ASTM D3612, and ANSI/IEEE C57.104, respectively are the standards associate with sampling, testing, and analyzing the results. In this report we analyze the DGA data from field transformers and discuss the method to analyze the faults.
General Theory of Gas Generation
Electrical disturbance and Thermal decomposition are the two basis principal that causes the formation of gases in the operating transformer. There is no required high temperature to produce the gases but the gases generate at normal operating temperature .hydrocarbon molecule are the basic part of mineral oil in the transformer. The decomposition of these molecules is very complex in the thermal or electrical. This figure describe the types of thermal and electrical faults.
When chemical reaction take place carbon hydrogen and carbon-carbon bonds break. The fragments of hydrocarbon and hydrogen atom are formed. At the end these fragments attach to each other and formed different gases like hydrogen(H2), methane(CH4),acetylene(C2H2),ethylene(C2H4) and ethane (C2H6).Electric faults (thermal decomposition) generate different gases like carbon mono oxide(CO2),methane(CH4), monoxide (CO), hydrogen (H2) when the cellulose insulation involved in it. These gases are known as the key gasses.
The key gasses are generally assume the combustible (Carbon dioxide is not combustible).If the key gasses are combustible which is present in the transformer indicate the warmly that thermal, electrical or corona faults are exist.
The amount of key gases produce is directly proportional to the temperature and how much amount of material is present at that temperature and the gases produce at the moderate temperature will produces same volume at high temperature. So that the concentration of each gas which is present in the transformer mineral oils used as it and also used to predict the faults in the transformer. The concentration level of each gas (in ppm) is taken after analyze the sample and evaluating the result of DGA.
Its very important that any speedily increase in the concentration of key gases is the indication of some major problem in the transformer. Whenever DGA result shown exceed the key gas concentration level and the normal limits are also increase, then it is favorable to take another sample and analyze that one. After analyze the result compere both of these results which is taken before and after. Now look really concentration increase. The given table is derive ANSI/IEEE C57.104 information. The concretion level of different gases is given in the table.
There is problem to exceed the concentration level in the transformer so we should apply differ method to determining the seriously problems with in transformer. When we use these techniques the results of these key gases ratio compere with the suggest limits.
Thermal Faults
Low Intensity Discharge for Electrical Faults
High Intensity Discharge for Electrical Faults
Interpretation of Gas AnalysisDGA Diagnostic Tools
IEEE published a guideline for the investigation of gases that’s generate in the working transformer popularly known as ANSI ANSI/IEEEC57.104-1978 Standard. This stranded deal with the method of analyzing the, procedure of sampling, separating the gases in the transformer the result and uses of tools.
Dissolved Gas Analysis instrument are different of their formation, clarity and their correctness. A number of DGA diagnostic tools are simple addition or the one gases ratios for normal levels while others present of multiple gases ratios and each key gas ratio exist in some particular range values.
On-line DGA and Diagnostic Tools
Now a days the online Dissolved gas analysis create a good reputation for his excellent work and incredible measurements and also give wonderful data to the ratio based diagnostic instruments. The expert of DGA feel very easy with the help on line system .they need the snapshot of the condition of transformer and know the present dynamic condition when the transformer is working. Due to on line system introduced new feature which is unbelievable .Snapshots does not indicate diagnostic rate at that ratio. In fact due increase the market DGA in line introduced different combinations. It has also ability to count 8 diagnostic gases. These application are very important they take automate measurement and can show the accurate diagnostic instrument.
Thermal Faults
A large quantity of low molecular mass gases are produce due to decomposition of minerals oil, beta fluid like that methane and hydrogen and a minimum amount of higher molecular mass gas ethylene is also produce. Temperature of beta fluid is increase as a fault, the concentration level of hydrogen gas is increase with respect to the methane gas. So the temperature accompanied the significant quantities of gases which one contain high molecular mass firstly ethane and second one is ethylene. Hydrogen gas and the minimum amount of gas acetylene (C2H2) may be formed due to temperature increase at the upper border of range. The different gases like carbon mono oxide, carbon di oxide, and the vapor of water are produced at the decomposition of beta fluid, thermal cellulose decomposition with another solid insulation at this stage the temperature is very low with respect to the decomposition of oil. The rate formation is increase or decrease with respect to the temperature. The reason is that the paper come to degrade when the temperature low as the beta fluid. All its products in gases form are predict at the normal operating temperature of the transformer.
Low Intensity Discharge for Electrical Faults
Methane and acetylene is produced in small amount when hydrogen is produced at low intensity. As increase the discharge level of two gases acetylene and ethylene the concentration level of these two gases increase sigaficnty.
High Intensity Discharge for Electrical Faults
The produced quantity of acetylene become marked at the temperature reach 700 c to 1800c when the intensity of electrical ejection reaches arcing.
Different method to Analyze to Combustible Gases in DGA Transformer oil Testing
There are a number of method to predict the Dissolved Gas Analysis in the transformer which is filled with beta fluid. The following processor that are recommended by dielectric system
Evaluation of Transformer Condition Using Individual and TDCG Concentrations:
These methods are suggest by IEEE Standard C57.104.when we have not the previous Dissolved gas history then a four level processes is define to understand the risk of inside the transformer. In the given table the concentration of gases are defined.
Condition 1
Condition 2
In this stage it show that the combustible gas concentration is greater than the normal TDCG indicate and we should investigate the any single one gas increasing concentration for the specified level.
Condition 3
At this last condition these values indicate the proper transformer condition .TDCG indicate that the decomposition of beta fluid and the cellulose is uncontrolled. If we star doing work with transformer then the maximum chance that the transformer stop doing work due to out of order.
At this last condition these values indicate the proper transformer condition .TDCG indicate that the decomposition of beta fluid and the cellulose is uncontrolled. If we star doing work with transformer then the maximum chance that the transformer stop doing work due to out of order.
We can easily find the present condition of particular transformer by finding highest for a single one gas. A year old transformer as well as contain the level of gases that would be below the condition 1 and not enough acetylene is present in the transformer to detect.
Evaluation of Possible Faults by the Key Gas Method
Fault Type: Thermal decomposition of Beta Fluid
Ethylene and methane are produced from decomposition and along with small amount of hydrogen and ethane.
Fault Type: Thermal decomposition of Cellulose
Carbon mono oxide and carbon di oxide is produced for the decomposition of cellulose. Hydrocarbon oxide are also produced if the cellulose saturated with beta fluid.
Fault Type: Corona –partial discharge:
Principal Gas: Hydrogen Characteristics:
Hydrogen and methane is also produced due to ejection of corona. Carbon di oxide and carbon mono oxide is include if the corona take place in cellulose.
Fault Type: Arcing
Principal Gas: acetylene Characteristics:
Acetylene and Hydrogen produced a large amount from arcing and other gas carbon di oxide is also produced in cellulose if the any potential harm is involve and the carbon also exist in the oil.
Evaluation of Possible Faults by the Rogers and Doernenburg Ratios in the Transformer Oil.
it is righty said that the concentration gas ratio is more trustable way from which we can easily understand and predict the fault inside the transformer. Rogers and Doernenburg were developed these ratios in European.
The following ratios are used:
Ratio 1 (R1): CH4/H2
Ratio 2 (R2) C2H2/C2H4
Ratio 3 (R3) C2H2/CH4
Ratio 4 (R4) C2H6/C2H2
Ratio 5 (R5) C2H4/C2H6
Doernenburg Ratio Method, Step 1
A sample of gas is collect from the head space which was above the level of oil in the transformer.
Doernenburg Ratio Method, Step 2
Be sure your method of calculation is true. One of the concentration of gases like hydrogen, methane, C2H2 and C2H4 must be as well as two times of the L1 values (below) and concentration of other three gases increased to the value of limit L1and it show that the transformer is faulty. As minimum as concentration of a single one gas must be increase the L1 values that’s given below.
Dissolved Gases
|
L1 Value ppm
|
Hydrogen
|
100
|
Methane
|
120
|
Carbon Monooxide
|
350
|
Acetylene
|
35
|
Ethylene
|
50
|
Ethane`
|
65
|
Hydrogen 100 Methane 120 Carbon Monoxide 350 Acetylene 35 Ethylene 50 Ethane 65
Doernenburg Ratio Method,
Step 3
Step 3
Suppose that the analysis ratio is true for this transformer and also check the ratio in order of R1, R2, R3, R4.
Doernenburg Ratio Method,
Step 4
Step 4
Now look all the calculating ratios which is measured for a particular task exist in the given table. If the ratios is present in the table than our suggested diagnosis is true.
Doernenburg Ratio for Gases key
Indicated fault
Diagnoses
|
Ratio 1
|
Ratio 2
|
Ratio 3
|
Ratio 4
|
Thermal
Decomposation
|
.1-1.0
|
.75- 1
|
.1 - .3
|
.2 - .4
|
Corona
|
.01-.1
|
Not significient
|
.1- .3
|
.2 - .4
|
Arcing
|
.1 – 1
|
.75- 1`
|
.1- .3
|
.2-.4
|
Doernenburg ratios, Rogers ratios, and Duval’s Triangle Mode are some commonly used techniques include application.
Doernenberg ratios and Rogers ratios are recognized in the ANSI/IEEE
C57.104. CH4/
H2, C2H2/C2H4, C2H2/CH4, C2H6/C2H2 and C2H4/C2H6. (Hamrick, 2009-2010)
Doernenberg ratios and Rogers ratios are recognized in the ANSI/IEEE
C57.104. CH4/
H2, C2H2/C2H4, C2H2/CH4, C2H6/C2H2 and C2H4/C2H6. (Hamrick, 2009-2010)
Gases are also dissolved in mineral oils with different rates .We can easily find the fault by absorbs the ranges of ratios. The range of different gases is given in the table.
Rogers Ratios Method:
Rogers Ratio method have same process to measure the ratios as well as the process of Doernenburg method but three is only difference is that only three ratios are used in it. 
Duval’s Triangle Model is known in IEC Guidelines. The Duval Triangle Model (IEC 60599) is published in 1989 by increment in 2002.Calculate the total amount of three key gas ethylene (C2H4), ethylene (C2H4), ethylene (C2H4) and then divide total of all gases to calculate the percentage of each one gas and find the problems in transformer using the key gasses After that plot a triangle from these values which was absorbed.
In the triangle the temperature effect with ratio are shown like thermal fault < 300 ºC, thermal fault 300-700 ºC, thermal fault> 700 ºC; low-energy discharge; high
energy discharge; and partial discharge.
Sometimes the ratio to key gases CO2 and CO act as a alarm in the decomposition of cellulose .It is often seen that the ratio of formation of key gas CO2 is usually 7 to 20 time greater than CO. If the ratio of both these gases is greater than 7 then it consider to be at normal level and if the ratio of carbon di oxide and carbon mono oxide is 5or less than 5 then it is the indication of optional problem. Sometimes additional furan test is required to perform when if the degradation of cellulose is problem carbon mono oxide, hydrogen, methane and C2H6 are also increase. The transformer consider faulty for more inception if the ratio of carbon mono oxide and carbon di oxide ratio is 3 or less than 3 with the increased the furans. Due to overheating, chemicals and in the addition of Carbon di oxide, carbon mono oxide the cellulose decompose and released in to the oil. The mixture which formed during this process is known as Furans or furanic compound.
In the fault free Transformer the amount of furan is negligible in the oil (<100ppb). The amount of furans increase when the quantity of cellulose decrease. When the furan levels between 500 to 1000 ppb then it shows the cellulose growing older and showing the effects of increasing age. And when the furan levels greater than 1500 ppb then it show the potential harm of insulation.
These are some assumption of key gases in the transformer.
Assumption #1:
Analysis:
Assumption # 2:
Transformer show alert as overheated cellulose because carbon monoxide is present in it So it is very easy and reliable to investigate the cellulose problems solely by looking the carbon mono oxide.
Analysis:
In the triangle the temperature effect with ratio are shown like thermal fault < 300 ºC, thermal fault 300-700 ºC, thermal fault> 700 ºC; low-energy discharge; high
energy discharge; and partial discharge.
Sometimes the ratio to key gases CO2 and CO act as a alarm in the decomposition of cellulose .It is often seen that the ratio of formation of key gas CO2 is usually 7 to 20 time greater than CO. If the ratio of both these gases is greater than 7 then it consider to be at normal level and if the ratio of carbon di oxide and carbon mono oxide is 5or less than 5 then it is the indication of optional problem. Sometimes additional furan test is required to perform when if the degradation of cellulose is problem carbon mono oxide, hydrogen, methane and C2H6 are also increase. The transformer consider faulty for more inception if the ratio of carbon mono oxide and carbon di oxide ratio is 3 or less than 3 with the increased the furans. Due to overheating, chemicals and in the addition of Carbon di oxide, carbon mono oxide the cellulose decompose and released in to the oil. The mixture which formed during this process is known as Furans or furanic compound.
In the fault free Transformer the amount of furan is negligible in the oil (<100ppb). The amount of furans increase when the quantity of cellulose decrease. When the furan levels between 500 to 1000 ppb then it shows the cellulose growing older and showing the effects of increasing age. And when the furan levels greater than 1500 ppb then it show the potential harm of insulation.
These are some assumption of key gases in the transformer.
Assumption #1:
An arc is produced in the working transformer caused by the Acetylene, So it is easy to diagnose the condition of arcing solely by the help of the acetylene.
Analysis:
The practitioner does not investigate and understand the nature of the arc by the help of this assumption. The question that is it a not dangerous condition of sparking partial discharge in the transferor oil from the grounded part? There is not a first class of very high dangerous to discharge energy? The high temperature in the transformer produced acetylene and the acetylene make a fault in the transformer oil or rather then produced an electrical arc? It is dam possible that it is the result of mixing or leakage the oil in transformer between the main tank and the LTC tank? All these question are not answered at easily but take the ratios of acetylene to the other gasses into the account. The in accurate result of findings does not mean there is a less dangerous or permission to a high problem to worsen. Due to lake of correct result the situation become over treated like de energizing, draining, incepting the tank and found no prove the reason is partial discharge cannot be seen with bear human eye.
Assumption # 2:
Transformer show alert as overheated cellulose because carbon monoxide is present in it So it is very easy and reliable to investigate the cellulose problems solely by looking the carbon mono oxide.
Analysis:
According to the IEC data of incepted case in service .During the formation of carbon monoxide using the identifier paper involvement in a problem. A inaccurate result will be provided in about 65% of case.
The amount of carbon mono oxide increase it does not mean that any fault involving paper. The fault predicting depend very strongly on the presence of carbon di oxide amount. But actually the increasing amount of carbonmono oxide are directly related to the oxidation of oil it is seeing a large number cases and at the end the result shown increases the heating effect. Now a day all the transformer is equipped with the air preservation system because a small amount of oxygen is always present in the transformer due to leaks in these systems.
Carbon mono oxide by itself not a trustable and safe indicator. It damage the localized insulation paper and these are the following reason behind,
· The amount is commonly reduced by dilution in a large amount of oil.
· The level is affected by oil temperature absorption and desorption by paper insulation caused by load.
· Its ability to move out in the transformer depend upon the oil expansion system type and the bounding of transformer how tightly is sealed.
Assumption # 3
Hydrogen gas predict the faults and the partial discharge so it is very sinificient to measure the hydrogen.
Analyze:
Hydrogen is also a key gas and it is present in all problems. So it not to use as a diagnostic gas but it is a predictor. It should be gather with other gases to find the problems with them as a ratio based analysis.in the key gas method three other gases are also include. The methane gas gives batter response when it is combine with hydrogen as a as diagnose and It happened when gases ratios are used. The reason behind is hydrogen gas soluble minimum amount oil. It has also high diffusion ability. (Serveron Corporation)
Conclusion:
In summary the indicator used in the transformer to predict the potential problems in the transformer should not be limited its totally depends upon the concentrations of the dissolved key gases. Identified the problems by trending the gas dissolved levels because we take some step before the tragic failure of the transformer. If the results of key gases concentration is different than we should take another sample to check the correctness of the result. If it clear that the concentration level is increase then use the well knows method to find the problems in the transformer and try to solve the problem.
Dissolved Gas Analysis organization work very hard for batter diagnostic instruments and their progress in this field. DGA expert always gets latest news and takes benefit. Mostly instruments are very good to perform than others. It is very reliable and comfortable to analyses the condition of the transformer. It is very strong program to analyses in laboratory as well as online dissolved gas analysis approaches.
We also analyze that the gasses generated in the transformer occupy with the beta fluid. They have same rule to analyze these gases and the conventional transformer oil and from the test its shows that the amount of gases that produced in the beta fluid due to different types of faults are same for those gases that is produced in the transformer convention oil. Another similarities is solubilizes of gases in the transformer is approximately 10 percent and the same amount of soluble in the beta fluid.
These graphs dhow the percentage faults at different level.
Thanks for Suggestion
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