Electrical Power Systems

Assignment 2:

Examine and analysis real, apparent and reactive power components in linear loads?

Evaluate the optimum capacitor value for unity / near unity power factor for power distribution system?

Conduct a series of simulation assessments to determine the power factor in linear and nn linear loads connected at distribution networks ( pspice software or matlab)

Explain your own thoughts, observation for each of the tests above and provide your profesionl comments

**An Investigation into the load flow analysis in 7 bus distribution network with and without renewable energy using ETAP software**

Key Words: Load flow analysis; distribution network; renewable sources

Software Tools: ETAP

Weighting: 30%

Submission Deadline: Submission of the final report by:

**21:00 hours Thursday 24th of November 2016**

** **

Submission, Format and Process: Research reports will be submitted via Turnitin online submission system via the module area of Course Resources. Submissions need to be made using standard text document using black text on white paper in 11 point font size. Further guidance is available via the Turnitin submission interface.

Description: Load flow study is a numerical analysis of the flow of electric power in an interconnected system. 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 load-flow study is the magnitude and phase angle of the voltage at each bus, and the real and reactive power flowing in each line.

You are required to submit an assignment of 2000 to 2500 words only. Directed studies work introduced in the lecture, laboratory & tutorial sessions will form the basis for most of the assignment topics but you are encouraged to extend the assignment according to your own interests and professional skills development needs and to use the assignment as a platform for becoming more proactive with electrical power system design, analysis, simulation, prototyping, test, validation and wider personal development opportunities.

The assignment must include and explore the following prescribed topics:

(1) Use ETAP software to construct a distribution power network of at least 7 buses. You can start your distribution network at 125 kV and take it down to 0.415 kV (125 kV – 33 kV – 11 kV – 0.415 kV). You should have industrial loads connected to the 11 kV as well as domestic loads connected to the 0.415 kV. It is up to you to select the details of your loads (power and P.F.).

(2) Carry out the load flow study of the network in (1). In your study you should comment on the magnitude and phase angle of the voltage at each bus, and the real and reactive power flowing in each line.

(3) Carry out the load flow study calculations for at least a two bus network using the Newton-Raphson Method.

(5) Explain your own thoughts, observation for your simulation results and provide your professional comments.

This assignment is designed to support your development as an undergraduate learner and to outline a process of personal verification and evaluation. The purpose of learning is to develop competent graduates that are knowledgeable, creative, has capabilities of design and build skills and vision to bring fresh potential ideas to business. Use this assignment as a first step in redefining yourself as a professional.

In completing this assignment the student will have developed skills in:

- Identify, select, programme and test suitable power flow techniques and algorithms to solve network power, voltage and current distributions

**Assignment resources:**

- LCUCK Electrical Power Laboratory.
- Lecture, Tutorial and Practical notes available on the university black board
- Reference text books available in the library

Introduction.

It is important to study and analyse the load flow in a network for planning the future expansion of the power systems and also determining the best operation of existing systems. The economical operation of the existing system depends upon knowing the effect of generation dispatch on the loading of transmission lines and transformers and the voltage conditions of various buses of the power system. Load flow study is the determination of the voltage, current, power, power factor and reactive power at different points in power networks under normal operation. The information obtained from studying the load flow is usually the phase angle and the magnitude of the voltage at each bus and the real and reactive power flowing in each line. This include the current in polar or rectangular form. These studies are essential for designing a new power system, the solution obtained from these studies gives the initial conditions of the system for carrying out fault analysis and stability, also to evaluate the transient behaviour of the system. Load flow studies are made on digital computers and in analog computers known as ac calculating board which was a way of doing analysis before using computers. Whether ac calculating board or a digital computer performs the load flow study of a system the data required are the same. The starting point is always a one line diagram. It is important that operating conditions must always be selected for each study. Also at each bus the real power into network must be specified except the bus called usually the swing bus and is the bus to which the power generator is connected. The other buses are classified as load bus and voltage controlled bus. Of course the net power flow to the system could not be fixed in advance at every bus because the loss in the system is not known until the study is complete.

Nowadays exists a number of software implementation of power flow studies and these software implementation perform other types of analysis such as short-circuit fault analysis and economic analysis. Some software use linear programing to find optimal power flow, the condition which gives the lowest cost for power generated.

For this assignment the use of ETAP is implemented to study the power flow in the power system and Newton Raphson solution method will be used for the solution of the resulting nonlinear system of equations.

Use ETAP software to construct a distribution power network of at least 7 buses. You can start your distribution network at 125 kV and take it down to 0.415 kV (125 kV – 33 kV – 11 kV – 0.415 kV). You should have industrial loads connected to the 11 kV as well as domestic loads connected to the 0.415 kV. It is up to you to select the details of your loads (power and P.F.).

Answer.

In figure below is shown what I built in ETAP software as a single line diagram for a power flow analysis. A single line actually represent a three phase power system containing Generator, Buses, Transformers and various Loads. The Bus is a meeting point of various components in power system. Voltage magnitude and phase angle at all the Buses, real power and reactive power flowing over all lines and transformers, losses and power injected at all the Buses is obtained from power flow study. Steps involved in power flow study are 1) Representation of the system by one line diagram. 2) Determining the impedance diagram. 3) Formulation of non-linear algebraic power flow equation. 4) Solution of power flow equations by iterative form.