Loadflow Analysis: This a study of the Electrical Power System to determine the voltage profile or voltage distribution in the Electrical Power System. The analysis determins the voltages at the various buses. This analysis is carried out using the Loading at the various buses, and the various load centers, the Y-BUS matrix, calculated using the system parameters, system configuration and system topology. The initial calculation is carried out using guessed values of voltages at the various buses and the specified voltage at the slack bus or reference bus which is fully specified and does not require any calculation unless to determine the total Power in the system ie. the Power at the reference bus usuall designated as Bus(1). Convergance occures when an acceptable degree of accuracy is attained. This determined by comparing the error level of succesive results of the Loadflow analysis with a preset error level. This error level is a trade off between speed and accuracy which in turn depends on what the analytical result will be used for . The result of Loadflow analysis is used for the Management of the Electrical Power System, contingency provision, planning, operations and also form the basis for other studies of the Electrical Power System. Fault Analysis: Stability Studies: State Estimation
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That’s a good one. Thank you and God bless you.
Its a good feelin being in this sight mr. Uchenyi,my able lecturer from esut,enugu..nigeria…….please keep up the work on power.
NAME: OJOBO ANTHONY
DEPARTMENT: ELECTRICAL & ELECTRONICS ENGINEERING
REG. NO: ESUT/2009/102202
COURSE: EEE 352 ASSESSMENT
I have understood many things in this course, such as how power can be generated from many sources such as Coal, Nuclear Energy, Wind, Hydro Electrical etc.
I also learnt the factors to be considered when choosing a plant type such as
• Fixed charge,
• Economic power production etc.
I understand that after power generation, it can be transmitted through overhead wire to the distributing station and finally to consumers. And that transmission line has the following parameters; Resistance, Inductance, Capacitance and Conductance. Power is transmitted at high voltage in order to reduce power loss due to I2R.
I also learnt about transformer as an electromechanical device that is used to step up or step down alternating voltage. There are two types of transformers known as step up transformer and step down transformer. I also learned about ideal transformer and practical transformer. I also learned what efficiency of a transformer is and how to calculate it. I also learnt numerous other calculations.
It was great studying this course.
To God be the Glory!
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EUNGU STATE UNIVERSITY OF SICENCE AND TECHOLOGY.
NAME ONYIA IFEANYICHUKWU .C.
DEPT. ELECTRICAL ELECTRONICS ENGINEERING.
REG. NO. ESUT/2008/94390
SERIAL NO. 400 LEVEL
COURSE EEE 454/451
DATE 17TH May , 2012.
THE CHARACTERISTICS OF ELECTRICAL COMPONENTS.
These are components of electrical characteristics they are as follows:
• Positive sequence components: It consist of three phase equal in magnitude displaced from each other, by 125o from each the original phasor.
• Negative sequence components: It consist of three phasor equal in magnitude displaced from each by 120o in phase and having the phase sequence opposite that of the original phasor.
• Zero sequence components: It consist of three phasors equal to the in magnitude with zero phase displaced from each other.
NOTATION
+ve positive sequence component 1
-ve negative sequence component 2
Zero sequence component 0
Va=va1+ va2 + va0
Vb=vb1 + vb2 + vb0
Vc=vc1 + vc2 +vc0
EEE 451
THE REGULATION IEE
IEE regulation for control distribution and excess power protection section including the FFG.
Every consumer installation supply from external source shall be adequate controlled by switch gear accessible to the consumer, this switch gear incorporate the following
a. Means of isolation.
b. Means of excess circuit protection (surge)
c. Means of earth leakage protection switch gear is control device used to control power devices.
THE GENERAL SEQUENCE OF MAIN SWITCH GEAR.
The general sequence of main switch gear shall be:
I. Series fuse.
II. Neutral link if any
III. Watt hour meter if any and time switch if any
IV. Link switch and consumer main fuse or earth current CB within or without earth leakage trip.
V. Consequence distribution board of the consumer main fuse may be omitted under certain condition when earthing, the earthing conductor, should be well digged or buried with charcoal or salt so that the ground will conduct well.
Good lerning
EUNGU: STATE UNIVERSITY OF SICENCE AND TECHOLOGY.
NAME: CHIBUOGWU IFEANYI PAUL
DEPT: ELECTRICAL ELECTRONICS ENGINEERING.
REG. NO: ESUT/2007/88818
LEVEL :500 LEVE
COURSE CODE: EEE 554
DATE: 24TH May , 2012.
WHAT I HAVE LEARNT SO FAR
State Estimation
State Estimation is a study of the Electrical Power System with a view of determining the state of the Electrical Power System at any given time using state variables which may or may not be measurable, observable or accessible. When measurements are made in State Estimation, these measurements are accompanied by noise. This noise has to be accounted for, for reliable and effective State Estimation.
Load flow Analysis.
Load Analysis is carried out as part of Electrical Services Design. It is important because it helps in protection, specification and load balancing for optimum utilization of available facilities. To do this, you need to know what the building is intended for. This will help the Engineer to make adequate provision for all the Electrical devices, appliances and facilities. These are grouped into circuits and protected appropriately with the right fuses or circuit breaker (MCB), Miniature Circuit Breaker. Once the design is concluded and the specifications made, the installed load capacity is determined. Appropriate cable sizes and cable types are selected. Care is taken to ensure that the three phase load is balance, to ensure that the installation be effective.
This is basic standard procedure.
From this analytical procedure, one can determine the voltage at any given bus given the voltages at the other buses and the system parameters as well as the system configuration and the loading at the various buses.
Since the voltages at the various buses are not known initially, we start with an educated guess and calculate these voltages iteratively until an acceptable degree of accuracy is attained.
There are two main options used for Load flow analysis. These are the Gauss Seidel Method and the Newton Raphson method. The Gauss Seidel method uses the algebraic expressions derived above iteratively to determine the voltages at the various buses. On the other hand, the Newton Raphson iterative method uses error analysis applied to the Taylor series expansion of the power system showing an expression for complex power about a singularity ignoring higher order derivatives and solving for the associated error and using the error to improve the guessed value or that result after each iteration until an acceptable degree of accuracy is attained.
In the expression above;
The idea is to calculate the voltage using estimated values of voltages at the other buses or the previously calculated voltages (being an iterative method) in addition to real and reactive power values delivered to the bus from generators or supplied to the load connected to the bus as well as self and mutual admittances of the nodes.
The quantities are used to form the network equation with the aim of finding the voltage.
Power Flow Methods
• Newton-Raphson method
• Gauss-Seidel method
• Fast Decoupled method
•
Load Flow Analysis helps to ensure that cables, transformers, transmission lines are sized appropriately to carry required load. To make sure that the transformer taps are set appropriately to obtain satisfactory voltage profile within the area of study.
Required when
• There is a significant plant expansion
• New local generation is or is proposed to be added
• New utility feed has been installed
• New large motors have been added to the system
• New transformers have been installed
• Addition of significant loads
The Gauss – Seidel Method
In the Gauss-Seidel Method, as the corrected voltage is found at each bus, it is used in calculating the corrected voltage at the next. This calculation is carried out at each bus except the swing bus throughout the network to complete the first iteration. The swing bus is fully specified hence no calculation is carried out on it or required to be carried out. You could however calculate the total power of the system at this bus. Ie. The total power delivered to the system.
This method involves an iterative solving of linear algebraic equations.
Note that it is possible for the voltages to converge upon an erroneous solution if the original voltages are widely different from the correct values.
To prevent this, original values of reasonable magnitude and which do not differ too widely in phase are chosen.
Unwanted solutions can be detected by the experienced engineer easily by inspection of the result since the voltage of the system do not normally have a range in phase wider than 45 degree and the difference between nearby buses is less than 10 degree and often very small.
Newton Raphson Iterative Method
The Electrical Power System is expressed as a function of ‘δ’ & ‘V’. It is then expressed as a Taylor Series.
It is noted that there are differential quantities in the Taylor Series expression. Second order values of the differential and higher order values are ignored, because their effect is minimal.
Incremental change ‘ΔV’ & ‘Δδ’ are approximated to error quantities or these differentials.
An iterative method is set in motion such that the difference between the calculated complex power and the specified Power is as a result of this error quantity. This error is hence calculated and used to improve the assumed value of the voltages and angles. The exercise is continued until an acceptable degree of accuracy or a given level of accuracy is established or reached.
Consider a guessed solution x(0)
Let f(x(0)) + Δx(0) = 0
If we expand f(x) about x(0) we obtain
f(x(0)) + Δx(0)(df/dx)(0) + ½ (Δx(0))2(d2f/dx2)(0) + ……..+ = 0
Δx(0) is the error associated with the guess x(0)
If the error is small, the higher order terms can be neglected to give
F(x(0)) + Δx(0)(df/dx)(0) ≈ 0
The error can be calculated as
Δx(0) = – f(x(0))/((df/dx)(0))
If we add this error to the original guess, we then have an improved guess, such that
X(1) = x(0) + Δx(0) = x(0) – f(x(0))/(df/dx)(0)
This procedure is repeated until the correct or specified degree of accuracy is attained.
X(a+1) = x(a) + Δx(a) = x(a) – f(x(a))/(df/dx)(a)
Consider ‘n’ dimentional Equations
x(0) =
Here only the first derivatives are considered.
F1(x(0)) +(df1/dx1)(0)Δx1 +………………….+ ((df1/dxn)(0)) Δxn ≈ 0
.
.
.
.
Fn(x(0)) +(dfn/dx1)(0)Δx1 +………………….+ ((dfn/dxn)(0)) Δxn ≈ 0
+ ≈
Using compact matrix – vector notation
f(x(0)) + J(0) Δx(0) ≈ 0
hence
Δx(0) ≈ -[J(0)]-1f(x(0))
This error vector is added to the original guess and the process repeated in an iterative way such that.
x(a+1) = x(a)- [J(a)]-1f(x(a))
where ‘a’ is the iteration counter ie counts the number of iterations. (0) stands for guessed values.
J ≡ is an nXn matrix of partial derivatives (dfi/dxj) called a Jacobian matrix.
In Power Systems Analysis,
Notice that the reference bus is not included.
This is because it is fully specified. This gives a (2n-2) – dimensional state vector.
By expanding functions for real and imaginary power ‘fip’ and ‘fiq’ in Taylor Series around the initial guess, we have.
Pi ≈ fip(0) + (dfip/dδ2).Δδ2(0) +………+ (dfip/d|vn|)(0).Δ|vn(0)|
For i = 2,…………,n
Qi ≈ fiq(0) + (dfiq/dδ2).Δδ2(0) +………+ (dfiq/d|vn|)(0).Δ|vn(0)|
fip(0) & fiq(0) represent real & imaginary (reactive) power leaving bus ’i’ or associated with bus ‘i’ if the bus voltage are set at guessed values.
The difference in power is also called Power Mismatch at a given bus. This is the difference between the measured Power at any given Bus and the calculated power at the same given bus using bus parameters like voltages and admittance and the angle of the voltage ie the power factor. Note that these voltage values and their angles could be guessed values or improved values after each iteration, until an acceptable degree of accuracy is attained. Ideally if the values used for the calculations are correct, there should be no mismatch. This means that there should be no difference. Where there is an error in the values used for the calculation, there will be a mismatch and this is used for calculating the error associated with these parameters and variables. These calculated errors are then used to improve the values of these parameters and these variables used for the calculation subsequently. This procedure is repeated iteratively until an acceptable degree of accuracy is attained.
ΔPi(0) ≈ Pi – fip(0)
ΔQi(0) ≈ Qi – fiq(0)
≈
ΔU(0) ≈ J(0).Δx(0)
Procedure For Load Flow Analysis Using Newton Raphson Method
Guess x(0)
Compute ΔU(0)
Pi = |Yik||Vi||Vk|cos(δk+δi+ϒ)≈ fip
Qi = – |Yik||Vi||Vk|sin(δk+δi+ϒ)≈ fip
For i = 1,2,………………n
Note that
Si =
Si = Pk – jQk = Vk* YikVk
For i = 1, 2, ………………n
Compute the Jacobian Matrix
Solve the voltage error vector ie
Δx(0) ≈ (J(0))-1.ΔU(0)
Add voltage errors to the initial guesses to obtain an upgraded state vector.
The process is repeated.
NB.
G-S – Voltage error used as a convergence measure. Ie the difference b/w subsequent iterative results.
N-R – Power Mismatch, real and reactive used for this purpose.
Bus or Busbar
A bus is also called a busbar. This is where connections are made in the power system. There three main types of buses in the Power System. These are the
1. Slack bus
2. The Voltage controlled bus or generator bus
3. The Load bus.
The Slack bus is the reference bus. It is also called the Swing bus. It is fully specified and no calculation is required at this bus. How ever all the calculations in Load flow analysis are made with respect to the slack bus. The total complex power is also calculated at the slack bus.
The Voltage controlled Bus
Usually, the voltage controlled bus has a Generator connected to it hence it is also called a Generator Bus.
The Reference Bus
The Reference Bus has to be a Generator Bus (with a Generator connected to it) or a Tie Bus (for interconnectivity of major system networks)
Load Bus.
This is the most numerous Bus in the Electrical Power System.
Power system Faults and Electrical power protection
Fault analysis
Fault Analysis is a study of the Electrical Power System after a fault with a view of determining the voltage and current distribution subsequently. The result of Fault Analysis is used in protection scheme design for CT. (Current Transformer) VT.(Voltage Transformer) Relay and CB. (Circuit Breaker) specification. There are two kinds of faults in the system namely, balanced and unbalanced faults. Balanced faults give rise to balanced phasors which are analysed using single line equivalent circuit. On the other hand, unbalanced faults, give rise to unbalanced phasors which are analysed using symmetrical components.
Faults are usually associated with fault impedances. In fault analysis, these impedances are assumed to be small and hence neglected ie. (Negligible) . This can be explained by the fact that when there is a short circuit, the current is very high because the impedance is very low, hence the assumption of zero fault impedance in the analysis of faults. These analytical results are also used for the design and specification of transducer, CT (current transformers), VT(voltage transformers), and CB(circuit breakers) and relays used in Electrical Power System Protection.
The fault analysis of a power system is required in order to provide information for the selection of switchgear, setting of relays and stability of system operation. A power system is not static but changes during operation (switching on or off of generators and transmission lines) and during planning (addition of generators and transmission lines).
Thus fault studies need to be routinely performed by utility engineers (such as in the CEB).
Faults usually occur in a power system due to insulation failure, flashover, physical damage or human error. These faults may either be three phase in nature involving all three phases in a symmetrical manner, or may be asymmetrical where usually only one or two phases may be involved. Faults may also be caused by either short-circuits to earth or between live conductors, or may be caused by broken conductors in one or more phases.
Sometimes simultaneous faults may occur involving both short-circuit and broken conductor faults (also known as open-circuit faults).
Balanced three phase faults may be analyzed using an equivalent single phase circuit.
With asymmetrical three phase faults, the use of symmetrical components help to reduce the complexity of the calculations as transmission lines and components are by and large symmetrical, although the fault may be asymmetrical.
Fault analysis is usually carried out in per-unit quantities (similar to percentage quantities) as they give solutions which are somewhat consistent over different voltage and power ratings, and operate on values of the order of unity.
In the ensuing sections, we will derive expressions that may be used in computer simulations by the utility engineers
General procedure for fault analysis
In Electrical Power Systems Fault Analysis, the following procedure is followed.
• First the fault is identified and classified.
• A diagram is drawn illustrating the Fault condition.
• Equations describing the Fault are written. This is called the terminal condition.
• These equations are rewritten in symmetrical component form. ie. The original phasors are re-written using symmetrical components. The resulting symmetrical component equations are simplified.
• Symmetrical Component interconnection network diagram is drawn and analysed. This network has to be consistent with the set of simplified symmetrical component equations.
The result of the analysis is a set of symmetrical component currents and voltages. These symmetrical component currents and voltages are used to calculate the original phasors as a result of the fault using the relevant equations, transformation and relationship for conversion from symmetrical components to the original phasors.
Balanced and unbalanced faults
Balanced faults are faults in the Power system that affects the three phases equally. Balanced faults give rise to balanced phasors. Balanced faults are analyzed using single line equivalent circuit. This is because all the phases are identical. As a result of this, the positive sequence component network, which is active and hence non trivial, is analyzed to determine the voltage and current distribution after the fault. These results are used for protection scheme design. Examples of balanced faults are three phase open circuit fault, three phase short circuit fault, three phase short circuit to ground fault.
Unbalanced faults require symmetrical components for their analysis. The determined symmetrical component values are used to calculate the values of the current and voltage of the original phasors as a result of the fault.
Phasor
Phasors are vectorial representation of electrical quantities. Eg. I = 5/-30o A. This is a phasor of an inductive current which is 5amperes and lagging by 30degrees with respect to a reference axis which could for convenience is usually chosen to be the applied voltage responsible for the current in question. Any reference axis can be chosen; however there is a need for consistency especially when dealing with different electrical quantities in the same system.
Stability studies
Stability Studies is a study of the Electrical Power System with a view of determining if the System will retain Synchronism after a perturbation. There are three main studies in stability studies. These are
1. Transient stability studies
2. Dynamic stability studies, and
3. Steady state stability studies.
Stability Studies is the ability of the Power system to return to normal operation after a disturbance.
Transient Stability studies deals with the ability of the Power System to remain in synchronism following major disturbances such as transmission line faults, sudden load changes, loss of generating unit or Electrical Power System Transmission line switching.
Single line diagram
The single-line diagram is the blueprint for electrical system analysis. It is the first step in preparing a critical response plan, allowing you to become thoroughly familiar with the electrical distribution system layout and design in your facility.
Whether you have a new or existing facility, the single-line diagram is the vital roadmap for all future testing, service and maintenance activities. As such, the single-line diagram is like a balance sheet for your facility and provides a snapshot of your facility at a moment in time. It needs to change as your facility changes to ensure that your systems are adequately protected.
An effective single-line diagram will clearly show how the main components of the electrical system are connected, including redundant equipment and available spares. It shows a correct power distribution path from the incoming power source to each downstream load – including the ratings and sizes of each piece of electrical equipment, their circuit conductors, and their protective devices.
In many process facilities, loads are continually added or removed in small increments. The net effect is not always seen until some part of the system becomes overloaded or exhibits other problems. Many times circuits are added without appropriate modifications of the standard settings on the associated upstream circuit breakers. Regardless of which protective devices you use, they must be coordinated with regard to their time/current curves and with each other. The single-line diagram provides the roadmap to enable proper design of equipment, redundancy, and protection.
An up-to-date single-line diagram is vital for a variety of service activities including:
• Short circuit calculations
• Coordination studies
• Load flow studies
• Safety evaluation studies
• All other engineering studies
• Electrical safety procedures
• Efficient maintenance
An electrical grid
An electrical grid is an interconnected network for delivering electricity from suppliers to consumers. It consists of three main components:
1) Power stations that produce electricity from combustible fuels (coal, natural gas, biomass) or non-combustible fuels (wind, solar, nuclear, hydro power);
2) Transmission lines that carry electricity from power plants to demand centers; and
3) Transformers that reduce voltage so distribution lines carry power for final delivery.
How Power Grid System Works
Electricity generation stations throughout the Nigerian States are interconnected in a system called power grids.
This allows electricity generated in one state to be sent to users in another state. It also allows distant power generation stations to provide electricity for cities and towns whose power generators may have failed or been destroyed by some accident or sabotage.
In the power industry, electrical grid is a term used for an electricity network which includes the following three distinct operations:
1. Electricity generation – Generating plants are usually located near a source of water, and away from heavily populated areas. They are usually quite large to take advantage of the economies of scale. The electric power which is generated is stepped up to a higher voltage-at which it connects to the transmission network.
2. Electric power transmission – The transmission network will move (wheel) the power long distances–often across state lines, and sometimes across international boundaries, until it reaches its wholesale customer (usually the company that owns the local distribution network).
3. Electricity distribution – Upon arrival at the substation, the power will be stepped down in voltage—from a transmission level voltage to a distribution level voltage. As it exits the substation, it enters the distribution wiring. Finally, upon arrival at the service location, the power is stepped down again from the distribution voltage to the required service voltage(s).
Infinite Bus:
By definition, and infinite bus voltage is an ideal voltage source
infinite bus has the following properties:
Bus voltage will remain constant under any loading
It has infinite capacity
Infinite bus-bars will are those whose frequency and the phase and magnitude of potential differences are not affected by changes in the condition of any one machine connected to it.
The variation in excitation of a synchronous machine connected to an infinite bus-bar will cause a large change in the reactive component supplied by the alternator and so change its power.
The increase in torque of the prime-mover of one alternator, it is further loaded and equivalent load is removed from the other unit (s) with which the machine is paralleled. If the output of the alternator, whose prime-mover torque has been increased, becomes more than the total load being supplied, then the other machine (s) will operate as synchronous motor (s).
The active and reactive power loading of an alternator operating on an infinite bus-bar is controlled by controlling the input power to it and ecitation respectively.
Y Matix
In power engineering, Y Matrix or Y bus is an n x n matrix describing a power system with n buses. It represents the nodal admittance of the buses in a power system. In realistic systems which contain thousands of buses, the Y matrix is quite sparse. Each bus in a real power system is usually connected to only a few other buses through the transmission lines. The Y Matrix is also one of the data requirements needed to formulate a power flow study.
The nodal admittance matrix form:
Starting from the single line diagram of a power system, there are four main steps in creating the Y Matrix. First, the single line diagram is converted to an impedance diagram. Next, all voltage sources are converted to their equivalent current source representations. From here, the impedance diagram is then converted to an admittance diagram. Finally, the Y Matrix itself is created.
Here, is the summed admittance of all power lines going directly from bus i to j (zero if no such). The parameter is often neglected, but could have a non-zero value representing the admittance-to-ground at bus i. The Y Matrix diagonal elements are called the self-admittances at the nodes, and each equals the sum of all the admittances terminating on the node identified by the repeated subscripts. The other admittances are the mutual admittances of the nodes, and each equals the negative of the sum of all admittances connected directly between the nodes identified by the double subscripts. As indicated by the provided construction, the Y Matrix is typically a symmetric matrix. However, extensions such as transformer modeling may make it asymmetrical.
For small transmission systems of about less than 10 nodes or buses, the Y matrix can be calculated manually. But for a realistic system with relatively large number of nodes or buses, say 1000 nodes, a computer program for computing Y is more practical to use.
Proposal for an integrated electrical power scheme
For sustainable electrical power supply, it is important to investigate the electrical power needs of different environment, societies, people, companies, industries, seasons, and regions. With this information appropriate and sustainable power supply can then proposed. Consider a highly industrialized and developed society, the electric power utility can supply the base load and ensure that the basic need are met such as heating, industry, public rail system, airports, schools and hospitals, and any other parts of the society that require a lot of energy.
Base loaded plants should used for this purpose. With the basic energy needs taken care of in a cost effective way, a study should be carried out to identify electrical appliances which can be powered with very minimal energy requirement. Some of these include computers, energy efficient luminaries, bulbs and lighting fittings, telephones. These items can be powered independently using stand alone renewable energy supply units for sustainable energy. When this is done the electric power utilizes can then concentration making electric power available for heavy duty machines, heating, industry and other needs in a very efficient way.
A solar energy supply scheme will require solar panels which will be connected to deep cycle batteries. These batteries will in turn drive and inverter or inverters which will have load connected to them
please sir help me in the project for my master. Topic PERFORMANCE OPTIMIZATION OF 330KV ENUGU ONITSHA HIGH TENSION TRANSMISSION LINE
ASSiGMENT On WHAT I HaVE LEARNT SO FAR i learnt that a prime mover is that thing neccesitate the function of an electric generator. I learnt that a generator is made of 2 main part; stator and rotor I learnt that a transformer is a static machine which transformer electric power from one alternating cct to another without change in frequency. It consist the primary and secondary winding turn. I learnt that a power transformer is one whose rating is kept above 2ooKVA .It is installed at generation sttation and substations I learnt that a distribution transformer are stepdown transformer which transforms standard 11kV or 6.6KV to servicable voltage of 44oV and always connected to supply ASSiGMENT On WHAT I HaVE LEARNT SO FAR i learnt that a prime mover is that thing neccesitate the function of an electric generator. I learnt that a generator is made of 2 main part; stator and rotor I learnt that a transformer is a static machine which transformer electric power from one alternating cct to another without change in frequency. It consist the primary and secondary winding turn. I learnt that a power transformer is one whose rating is kept above 2ooKVA .It is installed at generation sttation and substations I learnt that a distribution transformer are stepdown transformer which transforms standard 11kV or 6.6KV to servicable voltage of 44oV and always connected to supply ASSiGMENT On WHAT I HaVE LEARNT SO FAR i learnt that a prime mover is that thing neccesitate the function of an electric generator. I learnt that a generator is made of 2 main part; stator and rotor I learnt that a transformer is a static machine which transformer electric power from one alternating cct to another without change in frequency. It consist the primary and secondary winding turn. I learnt that a power transformer is one whose rating is kept above 2ooKVA .It is installed at generation sttation and substations I learnt that a distribution transformer are stepdown transformer which transforms standard 11kV or 6.6KV to servicable voltage of 44oV and always connected to supply ASSiGMENT On WHAT I HaVE LEARNT SO FAR i learnt that a prime mover is that thing neccesitate the function of an electric generator. I learnt that a generator is made of 2 main part; stator and rotor I learnt that a transformer is a static machine which transformer electric power from one alternating cct to another without change in frequency. It consist the primary and secondary winding turn. I learnt that a power transformer is one whose rating is kept above 2ooKVA .It is installed at generation sttation and substations I learnt that a distribution transformer are stepdown transformer which transforms standard 11kV or 6.6KV to servicable voltage of 44oV and always connected to supply line
can anyone help me with engr uchenyi s contact. its really urgent. thanks
good work sir keep it up
NAME: EZE PHILIP UCHENNA
REG NO: ESUT/2010/110369
COURSE: EEE 452 WHAT I LEARNT SO FAR IN YOUR COURSE IS GIVEN BELOW SYMMETRICAL COMPONENTS: These are balance phasors used to represent others phasor which may or may not be balance. These phasors could be n in number. In the electrical power system are system we usually used three set of phasors which are positive,negative and zero sequence. An unbalance phasor of n related phasor can be resolve into n system of balance phasors or symmetrical components of the original phasors. This phasor are equal in length and angle between them is equal. 1. POSITIVE SEQUENCE COMPONENTS: This consist of three phasor of magnitude displaced from each other by 120 degrees in phase and having thesame phase sequence as the original phasor. Va=Va1+Va2+Va0 2. NEGATIVE SEQUENCE COMPONENTS: These consists of three phasor equal in magnitude and having phase sequence opposite to that of the original phasor.Vb=Vb1+Vb2+Vb0. 3. ZERO SEQUENCE COMPONENTS: These also consists of three phasor equal in magnitude and with zero phase displacement from each other. Vc=Vc1+Vc2+Vc0. POWER CONSIDERATION: The reversal rule of matrix algebra which states that the transpose of the product of two matrix is equal to the product of the transpose of the matrices in reverse order. FAULT ANALYSIS: This is the study of electrical power system after a fault with a view of determining the voltage and current distribution subsequently. The result of fault analysis is used in projection scheme design (CT& VT) i.e current and voltage transformer relay ratio, tap setting and time dial setting and circuit breaker specification. It is used for contigence provision in the case of an emergency.
Name onaga tochukwu samuel Reg no esut/2010/110345 what i ve learn this semester (1)i learn about electrical power systen were we study analysis which include load flow,fault,stability studies etc(2)i also learn about long line parameter which are indactance,capacitance(3)i also learn about symmetrical component.
Name onaga tochukwu samuel Reg no esut/2010/110315 what i ve learn this semter (1)i learn about electrical power systen were we study analysis which include load flow,fault,stability studies etc(2)i also learn about long line parameter which are indactance,capacitance(3)i also learn about symmetrical component.
We learnt in this semester about “The Effect Of Impedance In A Power Line” power consideration is the reversal route of matrix algebra states that the transpose of a product of 2 matrix is equal to the product of the transpose of the matrix in reverse order. We also learnt about the “Line Resistance” and the factors that affect “line Resistance like Temperature, Skin Effect, Spiraling etc… Capacitance, Inductance and also line modeling.
Y-BUS MATRIX would not be left out and it was defined as a matrix of admittance used for the analysis of the electrical power system. Faulty Analysis is the study of electrical power system after a fault with a view of determing the current and voltage distribution subsequently, it is used for different purpose (1) For protection of scheme design (2) used in determing relay tap setting and time dial settings. Finally balanced and unbalanced fault.
Sir so far so good, I think I can say this is briefly what I have learnt this semester.
Thank you very much and remain blessed.
Name: CHUKWU MICHAEL CHISOM
Reg No: ESUT/2010/110307
Dept: Electrical/Electronics Engineering
Course: EEE 451
Level: 400 LEVEL
We learnt in this semester about Y-BUS MATRIX it was defined as a matrix of admittance used for the analysis of the electrical power system also Faulty Analysis was discussed as the study of electrical power system after a fault with a view of determining the current and voltage distribution subsequently, it is used for different purpose (1) used for determining the current transformer and voltage transformer ratio (2) used for contingency provision in the case of emergency. Balanced and Unbalanced fault i understood that balanced fault effects all phasor in power systems, example 3Ø open circuit faults, 3Ø short circuit faults and 3Ø short circuit to earth faults and these faults are analyzed using a single phase equivalent circuit.We also learnt in this semester about “The Effect Of Impedance In A Power Line” power consideration is the reversal route of matrix algebra and it states that the transpose of a product of 2 matrix is equal to the product of the transpose of the matrix in reverse order. We also learnt about the “Line Resistance” and the factors that affect “line Resistance like Temperature, Skin Effect, Spiraling etc… Capacitance, Inductance and also line modeling…
Thank very much sir for this opportunity to express what i have learnt this semester to you, may God continue to bless you as you do his work….
NAME: ANIAGO PAUL .N.
REG NO: ESUT/2010/110327
COURSE: EEE 451
DEPT: ELECTRICAL/ELECTRONICS
LEVEL: 400L
Name:MAJINDU KENNEDY CHUKWUEBUKA.
Reg. No: ESUT/2010/110295.
CONTINUOS ASSESMENT.
I learnt in this course that Loadflow Analysis is a study of
the Electrical Power System to
determine the voltage profile or voltage distribution in the Electrical Power System.
This analysis determins the voltages at the various buses.
I equally learnt that
Stability studies is the ability of the Electrical Power System to
return to normal operation after
a disturbance. This study is of three main types namely:
1. Transient Stability
studies,
2. The Dynamic Stability Studies and
3. Steady State stability studies.
Transient Stability Studies deals
with the ability of the Electrical
Power System to retain
synchronism following major
disturbances such as
transmission system faults,
sudden load changes, loss of
generating units or line switching.
Then , the Dynamic and Steady-State
Stability studies deal with a few machines undergoing slow or
gradual changes in operating conditions.
Another thing I learnt is what Fault Analysis is.
Fault Analysis is the study of the Electrical Power System after a fault with a view of determining the voltage and current
distribution subsequently.
This Fault is of two types namely: Balance and Unbalace Fault.
BALANCE FAULT: This simply refers to the Fault that affects all phases in the power systen equally. Example of this type of Fault are: 3-phase short circuit fault, 3-phase open circuit fault.
UNBALANCED FAULT: These are faults that affects the different parts of the electrical systems differently.
ENUGU STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ESUT NAME OKPATA EDWIN N REGNO ESUT/2010/110290 DEPT EEE LEVEL 400 ASSIGMENT ON EEE 454 . i have lanant alot in this course such as, foult analysis, stability study, state estimation and they application :foult analysis is the study of electrical power system after a foult with a view of determining the current and voltage distribution subsequential. the result of foult analysis is use for different purpose. use for protection schem design, use for determinig current and voltage transformer ratio, use for determing relay tap setting and time dual setting, use for contengency condition in the case of emergency this become inportant in the investigation of the system stability and peturbation in the event of these form. the analysis aid in determining the critical clearing time for circut breaker type of foult analysis balance and unbalance foult. stability study:this is the study to determine if the system wil retain synchronisim after peturbation
NAME: ONAH BENJAMIN OKECHUKWU DEPT: ELECTRICAL & ELECTRONICS ENGINEERING REG.NO: ESUT/2010/110934 COURSE: EEE452 1ST SEMESTER CLASS ASSESSMENT: *LOADFLOW ANALYSIS. This is a study of the electrical power system to determine the voltage profile or voltage distribution in the electrical power system. The voltage at the various bus are expected to be at their norminal values ( constant ) hence, in an ideal case, a voltage profile should be a flat voltage profile. A system is presumed to be under normal steady state operation. Now, to carry out this study, the following data is necessary. (a) system topology or configuration (b) system parameters (c) loading at each bus (d) bus types and characteristics. As stated earlier, this analysis yield, Buses: -Reference bus (generator bus and tie bus) -Voltage controller bus (generator bus) -Load bus (most numerious bus in the system). * What is Y-Bus matrix. Y-bus matrix is a matrix of admittances used for the analysis of the electrical power system. In the diageam of Y-Bus matrix SG=Generated complex power SG1=Generated complex power+1 SD=Complex demand power SD=Complex demand power+1 D=Demand Y=Admittance =1/Z YS=Series admittance YP=Parallel admittance Y12 = Y21 = Ys where Y11 is all the admittances connected to Bus “1” and Y22 is all the admittances connected to Bus “2” SYMMETRICAL COMPONENTS: These are balanced phasors used to represent other phasors which may or may not be balanced. In the electrical power system we usually used three sets of phasors which are +Ve, -Ve and zero(0) sequence components. *THREE MAIN COMPONENTS IN THE POWER SYSTEM. (1) Positive sequence component consists of three phasors equal in magnitude displaced from each by 120` in the phase and having the same phase sequence as the original phasors. Original phasors=> Va =Va1 + Va2 + Va0 (2) Negative sequence component consists of three phasor equal in magnitude , displaced from each other by 120` in phase and having a phase sequence opposite to that of the original phase Vb =Vb1 + Vb2 + Vb0 (3) Zero sequence component consists of three phasors equal in magnitude and with zero phase displacement from each other. Vc = Vc1 + Vc2 + Vc0. In Summary, Va= Va1 + Va2 + Va0 Vb= Vb1 + Vb2 + Vb0 Vc= Vc1 + Vc2 + Vc0 * POWER CONSIDERATION. The reverse rule of matrix algebra states that the traspose of the product of two matrices is equal to the product of the transpose of the matrices in rivers order. * SYSTEM PARAMETERS AND MODELING The following affects Line resistace. (i) Skin Effect (ii) Spirelling (iii) Temperature. (i) SKIN EFFECT: This is the tendency of A.c current to concentrate at the conductor surface thereby increases the effective resistance. This effect increases with frequency and is obtainable at 60Hz. (ii) SPIRELLING: Large power conductors are stranded and srands wound in spred fashion round conductor centre.
stability study this is a study to determine if a system would retain synchronism after peturbation. there are three type of stability studies : transient, dynamic and steady state. transient is the most sevear type of satability study. it has to do with major system foult example transmission line foult etc. dynamic: this has to do with when the generator are undergoing gradual changes in they operating condition. steady state: this is an investigation of power system under steady state, in this case the system are assumed to be quasistatic in naure. this analysis is divided into two first swing and multi swing. first swing: this is an investigation when generator control system or governing system effect is not taken into consideration becouse the time interval is the first swing and not being enough for the system to respond.on the otherhand when the study of peturbation last longer it is referred to as mult swing, in this case th governing and control system have enough time to respond
ENUGU STATE UNIVERSITY OF SICENCE AND TECHOLOGY.
NAME. MBAH DEREK .O
DEPT. ELECTRICAL ELECTRONICS ENGINEERING.
REG. NO. ESUT/2011/110473
SERIAL NO. 400 LEVEL
COURSE EEE 451
DATE 1TH march , 2015.
EEE 451
REGULATION
I learnt the IEEE Regulation guiding electrical installation especially the arrangement of e-component and the distance of some e-accessories (switch, socket, etc) from the ground and the certificates that are issued to show that the work was tested and completed.
EEE 452
I learnt the laws that guide an electromagnetic circuit (Amperes, Gauss, etc). Also I learnt the formula’s in transformer , its parameters(g,y,z,pi,etc)and its relationship with the continuity equation. It also taught me of the inductive nature of power (which is the imaginary part) which helped me to understand how motor draw more current than other electrical components.
EEE 454
I learnt how to analyze a power system using Load flow analysis; fault analysis, etc and how these formulas used in analyzing circuits for example analyzing voltage profiles in an electrical system)
Name: Ezeako Emmanuel .C
Reg no: ESUT/2012/137718
Class: 4th year
MY ASSESSMENT
ARMOURED CABLES:
When cables are armoured, it is done to achieve or to implement an underground wiring, or where where considerable mechanical strength is needed. The armouring consists of galvanised iron or steel wire or steel tape in single, double or even multiple layer according to requirement.
There are 2 types of armoured cables:
(1) Wire armouring
(2) Metal tape armouring
The choice for selection of a type of armouring depends on where it is to be used. The wire armouring is more rigid and uneasily bent, whereas the metal tape armouring is easier to bend. For example, we use wire armouring in a straight distant design where it doesn’t require bending, but use metal tape armouring in places where there’s a lot of corners so as to bend easily.
Metal tapes offers better mechanical protection than wire.
Name: Ezeako Emmanuel .C
Reg no: ESUT/2012/137718
Course: EEE 451
Level: 400
Date: 5th Feb. 2016
MY ASSESSMENT
ARMOURED CABLES:
When cables are armoured, it is done to achieve or to implement an underground wiring, or where where considerable mechanical strength is needed. The armouring consists of galvanised iron or steel wire or steel tape in single, double or even multiple layer according to requirement.
There are 2 types of armoured cables:
(1) Wire armouring
(2) Metal tape armouring
The choice for selection of a type of armouring depends on where it is to be used. The wire armouring is more rigid and uneasily bent, whereas the metal tape armouring is easier to bend. For example, we use wire armouring in a straight distant design where it doesn’t require bending, but use metal tape armouring in places where there’s a lot of corners so as to bend easily.
Metal tapes offers better mechanical protection than wire.
NAME: ILOEJE KENECHUKWU FRANCIS REG NO.: ESUT/2012/137622 DEPT.: ELECTRICAL AND ELECTRONICS ENGINEERING COURSE: EEE 554 LEVEL: 500 DATE: 15/03/2017
ASSESSMENT
WHAT I HAVE LEARNT THIS SEMESTER
Fault analysis is the study of electrical power systems after a fault with the view of determining the voltage and current distribution subsequently.
Two types of fault are:
Balanced fault and unbalanced fault
In Balanced fault, analysis is done on the single phase equivalent circuit. In Unbalanced fault, symmetrical components are used to carry out analysis.
Terminal conditions are equations used in determining or describing the state of a system after a fault.
Load flow analysis is the study of electrical power systems with the view of determining the voltage distributions at the various buses.
We carry out load flow analysis to study electrical systems and to determine the voltage level at each buses so as to be able to protect the system or prevent it from damages caused by voltage drops.
Methods of carrying out load flow analysis are:
Gauss Seidel method and Newton Raphson method
NAME: ILOEJE KENECHUKWU FRANCIS
REG NO.: ESUT/2012/137622
DEPT.: ELECTRICAL AND ELECTRONICS ENGINEERING COURSE: EEE 554
(POWER SYSTEM ANALYSIS)
LEVEL: 500 DATE: 26/03/2017
ASSESSMENT
WHAT I HAVE LEARNT
Fault analysis is the study of electrical power systems after a fault with the view of determining the voltage and current distribution subsequently.
Types of fault are:
Balanced fault and unbalanced fault
In Balanced fault, analysis is done on the single phase equivalent circuit.
In Unbalanced fault, symmetrical components are used to carry out analysis.
Terminal conditions are equations used in determining or describing the state of a system after a fault.
Load flow analysis is the study of electrical power systems with the view of determining the voltage distributions at the various buses.
We carry out load flow analysis to study electrical systems and to determine the voltage level at each buses so as to be able to protect the system or prevent it from damages caused by voltage drops.
Methods of carrying out load flow analysis are:
Gauss Seidel method and
Newton Raphson method
ENUGU STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ESUT
NAME :IFENIBO PASCHAL UCHECHUKWU
REG NO. ESUT/2012/137738
COURSE: EEE 554 &EEE 454
CARRY OVER 500L
ASSIGNMENT TO WRITE WHAT I HAVE LEARNT SO FAR.
1. Power-flow or load-flow studies are important for planning future expansion of power systems as well as in determining the best operation of existing systems. The principal information obtained from the power-flow study is the magnitude and phase angle of the voltage at each bus , and the real and reactive power flowing in each line.
2. Load flow studies common refer to as load flow or power flow are the back bone of power system analysis and design.
3. They are neccessary for planning, operation, economic scheduling and exchange of power between utlities period.
4. The primary objectives of the load flow calculation is to determing the steady state operating characteristic or power generating/transmission system for a given set of a busbar loads.
5. Economic dispatch practice usually specifies active power generation while the automatic voltage regulator ( AVR )maintains tje generator voltage magnitude.
6. Load are normally specified by their constant active and reactive power requirement.
7. Also I leanrt about NEWTON RAPHSON METHOD
which tells that it is a successive approximation procedure based on an initial estimate of the unknown and the use of TAYLOR’S series, of the non-linear equation for linearization.
Consider the function f(x) = 0.
8. I equally learnt that
Stability studies is the ability of the Electrical Power System to
return to normal operation after
a disturbance. This study is of three main types namely:
1. Transient Stability
studies,
2. The Dynamic Stability Studies and
3. Steady State stability studies.
Transient Stability Studies deals
with the ability of the Electrical
Power System to retain
synchronism following major
disturbances such as
transmission system faults,
sudden load changes, loss of
generating units or line switching.
Then , the Dynamic and Steady-State
Stability studies deal with a few machines undergoing slow or
gradual changes in operating conditions.
9. Another thing I learnt is what Fault Analysis is.
Fault Analysis is the study of the Electrical Power System after a fault with a view of determining the voltage and current
distribution subsequently.
This Fault is of two types namely: Balance and Unbalace Fault.
BALANCE FAULT: This simply refers to the Fault that affects all phases in the power systen equally. Example of this type of Fault are: 3-phase short circuit fault, 3-phase open circuit fault.
UNBALANCED FAULT: These are faults that affects the different parts of the electrical systems differently.
Thanks very much
HAPPY NEW DAY. THANK YOU AND GOD BLESS YOU.
ENUGU STATE UNIVERSITY OF SCIENCE AND TECHNOLOGY ESUT
NAME :UDEKWE VICTOR CHINEDU
REG NO. ESUT/2012/137688
COURSE: EEE 554 &EEE 454
CARRY OVER 500L
ASSIGNMENT TO WRITE WHAT I HAVE LEARNT SO FAR…
.
I learnt in this course that Loadflow Analysis is a study of
the Electrical Power System to
determine the voltage profile or voltage distribution in the Electrical Power System.
This analysis determins the voltages at the various buses.
I learnt what Fault Analysis is.
Fault Analysis is the study of the Electrical Power System after a fault with a view of determining the voltage and current
distribution subsequently.
This Fault is of two types namely: Balance and Unbalace Fault.
BALANCE FAULT: This simply refers to the Fault that affects all phases in the power systen equally. Example of this type of Fault are: 3-phase short circuit fault, 3-phase open circuit fault.
UNBALANCED FAULT: These are faults that affects the different parts of the electrical systems in another way.
Also Power-flow or load-flow studies are important for planning future expansion of power systems as well as in determining the best operation of existing systems. The principal information obtained from the power-flow study is the magnitude and phase angle of the voltage at each bus , and the real and reactive power flowing in each line.
Also I learnt,
These are components of electrical characteristics they are as follows:
• Positive sequence components: It consist of three phase equal in magnitude displaced from each other, by 125o from each the original phasor.
• Negative sequence components: It consist of three phasor equal in magnitude displaced from each by 120o in phase and having the phase sequence opposite that of the original phasor.
• Zero sequence components: It consist of three phasors equal to the in magnitude with zero phase displaced from each other.
NOTATION
+ve positive sequence component 1
-ve negative sequence component 2
Zero sequence component 0
Va=va1+ va2 + va0
Vb=vb1 + vb2 + vb0
Vc=vc1 + vc2 +vc0
Thank you Sir
God bless you Sir
Kalu Victor obialor
Esut/2011/110505
Power system analysis
What I learnt
UNDER FAULT ANALYSIS
I learnt the Definition of fault, types of fault, causes of fault and meaning of fault analysis.
Fault can be defined as the flow of a massive current through an improper path which could cause enormous equipment damage which will lead to interruption of power, personal injury or death.
Fault Analysis can be described as the process of evaluating the system voltages and currents various types of short circuit.
Fault; usually occur in power system due to insulation failure, flashover, physical change or human error. Fault can be caused by short circuit to earth or between live conductors or by broken conductors in one or more phases.
TYPES OF FAULTS
1. Balanced and
2. Unbalanced fault.
Load flow analysis: This is the study of power system to know the voltages at the various buses using the system configuration, loading at various buses, system topology and system parameters.
Types of load flow analysis
1. Newton Raphson iteration method.
2. Gauss Seidel iteration method.
Symmetrical components: These are set balanced phasors which can be used to represent or resolve an unbalanced system of ‘n’ related phasor into ‘n’ systems of balanced phasors. The symmetrical components have both length and angle between them equal.
Types of symmetrical components
1 Positive sequence components
2 Negative sequence components 3. Zero sequence components
Stability studies: this is the study of a system to know if a system will retain synchronism after perturbation or disturbance.
Types of stability studies
1. Dynamic
2. Transient
3. Steady state
CHIBUOKE CHIMOBI KENRICK
ESUT/2012/137639
ELECTRICAL/ELECTRONICS ENGR
500 LEVEL
QUIZ ON EEE 554
what I’ve learnt so far.
A vector is a quantity that has both magnitude and direction. phasor is a representation of electrical quantities using vectors. When unbalanced faults present its self you produce unbalanced results, but when you have balanced faults you have balanced results.
Balanced faults are easy to analyse we can solve this problem using phase equivalent circuit in power system.
symetric components are phasors which are balaned, but they are used to represent other phasor which may or may not be balanced. Types of symetric components 1) positive sequence components 2) negative sequence components, 3) zero sequence components. (1) Positive sequence component consists of three phasors equal in magnitude displaced from each by 120` in the phase and having the same phase sequence as the original phasors. Original phasors=> Va =Va1 + Va2 + Va0 (2) Negative sequence component consists of three phasor equal in magnitude , displaced from each other by 120` in phase and having a phase sequence opposite to that of the original phase Vb =Vb1 + Vb2 + Vb0 (3) Zero sequence component consists of three phasors equal in magnitude and with zero phase displacement from each other. Vc = Vc1 + Vc2 + Vc0.
LOAD FLOW ANALYSIS. this is a study of the power system with the view of knowing the voltage at the various buses using system configuration, loading at each bus, system topology and system parameters. Two types of Flow analysis are , Newton Ralphon iterative method. and Gauss Seidel iterative method
FAULT ANALYSIS. this is a study of power system after a fault with a view of finding the voltage and current distribution subsequently .type4s of faults 1) balanced faults 2) unbalanced faults
ST5ABILITY STUDIES. this is a study in power system to know if a power system retatains synchronism after perturbation. types of stability studies !) transient 2) dynamic 3( steady stability studies.
swing equation is an equation that determines the stability status of the electrical power system.
Onyemalu princewill onyeka
esut/2011/110419
Eee554
power system analysis
WHAT I HAVE LEARNT SO FAR
State Estimation
State Estimation is a study of the Electrical Power System with a view of determining the state of the Electrical Power System at any given time using state variables which may or may not be measurable, observable or accessible. When measurements are made in State Estimation, these measurements are accompanied by noise. This noise has to be accounted for, for reliable and effective State Estimation.
Load flow Analysis.
Load Analysis is carried out as part of Electrical Services Design. It is important because it helps in protection, specification and load balancing for optimum utilization of available facilities. To do this, you need to know what the building is intended for. This will help the Engineer to make adequate provision for all the Electrical devices, appliances and facilities. These are grouped into circuits and protected appropriately with the right fuses or circuit breaker (MCB), Miniature Circuit Breaker. Once the design is concluded and the specifications made, the installed load capacity is determined. Appropriate cable sizes and cable types are selected. Care is taken to ensure that the three phase load is balance, to ensure that the installation be effective.
This is basic standard procedure.
From this analytical procedure, one can determine the voltage at any given bus given the voltages at the other buses and the system parameters as well as the system configuration and the loading at the various buses.
Since the voltages at the various buses are not known initially, we start with an educated guess and calculate these voltages iteratively until an acceptable degree of accuracy is attained.
There are two main options used for Load flow analysis. These are the Gauss Seidel Method and the Newton Raphson method. The Gauss Seidel method uses the algebraic expressions derived above iteratively to determine the voltages at the various buses. On the other hand, the Newton Raphson iterative method uses error analysis applied to the Taylor series expansion of the power system showing an expression for complex power about a singularity ignoring higher order derivatives and solving for the associated error and using the error to improve the guessed value or that result after each iteration until an acceptable degree of accuracy is attained.
In the expression above;
The idea is to calculate the voltage using estimated values of voltages at the other buses or the previously calculated voltages (being an iterative method) in addition to real and reactive power values delivered to the bus from generators or supplied to the load connected to the bus as well as self and mutual admittances of the nodes.
The quantities are used to form the network equation with the aim of finding the voltage.
Power Flow Methods
• Newton-Raphson method
• Gauss-Seidel method
• Fast Decoupled method
•
Load Flow Analysis helps to ensure that cables, transformers, transmission lines are sized appropriately to carry required load. To make sure that the transformer taps are set appropriately to obtain satisfactory voltage profile within the area of study.
Required when
• There is a significant plant expansion
• New local generation is or is proposed to be added
• New utility feed has been installed
• New large motors have been added to the system
• New transformers have been installed
• Addition of significant loads Loadflow Analysis: This a study of the Electrical Power System to determine the voltage profile or voltage distribution in the Electrical Power System. The analysis determins the voltages at the various buses. This analysis is carried out using the Loading at the various buses, and the various load centers, the Y-BUS matrix, calculated using the system parameters, system configuration and system topology. The initial calculation is carried out using guessed values of voltages at the various buses and the specified voltage at the slack bus or reference bus which is fully specified and does not require any calculation unless to determine the total Power in the system ie. the Power at the reference bus usuall designated as Bus(1). Convergance occures when an acceptable degree of accuracy is attained. This determined by comparing the error level of succesive results of the Loadflow analysis with a preset error level. This error level is a trade off between speed and accuracy which in turn depends on what the analytical result will be used for . The result of Loadflow analysis is used for the Management of the Electrical Power System, contingency provision, planning, operations and also form the basis for other studies of the Electrical Power System. Fault Analysis: Stability Studies: State Estimation
NAME: EDEH MONDAY A.
DEPT: ELECTICAL AND ELECTRONIC ENGINEERING
REG: ESUT/2012/137636
COURSE: POWER SYSTEM ANALYSIS
CODE: EEE 554
LEVEL: 500 LEVEL
WHAT I LEARNT SO FAR
1. Symmetrical components: these are phasor which are balanced that can be used to resolve unbalance phasor
Types of symmetrical component
I. Positive sequence component
II. Negative sequence component
III. Zero sequence component
2. Load flow analysis: this is the study of the power system with a view of knowing the voltages at various buses using system configuration, topology, and load at each bus and system parameter.
Two main type of load flow analysis
1. Gauss Seidel method which is based on algebraic analysis,
2. Newton Ralpson method which is based on Taylor series expansion.
3. Fault analysis: this is the study determining the current and voltage subsequently
Types of fault
1. Balanced fault
2. Unbalanced fault
I. Stability studies: this is the study of electrical power system to know if the system will retain synchronism after perturbation.
Types of stability studies
I. Transient
II. Dynamic
III. Steady state
Name: Nnaji Ugochukwu Lawrence
Reg. Number: ESUT/2012/137669
Department: Electrical and Electronics Engineering
Level: 500L
Course: EEE 554
EEE 554 Quiz
What I’ve learnt so far
Fault Analysis: is a study of the power system after a fault has occurred, in order to determine the voltage and current distribution subsequently…
– There are two main kinds of faults namely;
1) Balanced Fault – one which affects the whole parts of the system.
2) Unbalanced fault – one which doesn’t affect the whole part of the system.
Balanced faults are analyzed using single phase equivalent circuit in the power system. Unbalanced fault is analyzed using symmetrical components.
Symmetrical Components are a set of balanced Phasors which can be used to represent or resolve am unbalanced system of n related phasors into n systems of balanced phasors
There are 3 major types of symmetrical components namely:
1) Positive Sequence component
2) Negative sequence component
3) Zero sequence component.
Stability Studies: Is simply the study to check if a power system will retain synchronism after perturbation or a disturbance.
– There are 3 types of Stability Studies namely;
1) Transient Stability Study: This deals with the ability of the power system to retain synchronism after major disturbances such as Transmission system fault, switching operations.
2) Steady State Stability Study: Deals with the ability of the power system to retain synchronism after a small and gradual change (disturbance) in the system.
3) Dynamic Stability Study: Deals with the ability of the power system to retain synchronism after continuous small disturbances in the system i.e when the system is undergoing small gradual changes.
In all stability studies, the objective is to determine whether or not the rotors of the machine being perturbed returns to constant speed of operation.
Load flow analysis: is simply the study of the power system with the view of knowing the voltages at the various buses.
There are two main types:
1) Newton Raphson iterative method
2) Gauss Seidel iterative method