ABSTRACT
This report is on stability study in electrical power system. The ability of an electric power system to reestablish the initial state (or one practically identical) after any disturbance manifested as a deviation from the initial parameter values for the system’s operation. The electric power sources in a power system are usually synchronous generators, which are coupled together by a common electric network in such a way that the rotors of all generators are in synchronized rotation. This mode, called the normal, or steady-state, mode, should be stable; that is, the power system must return to the initial state (or one practically identical) every time after a deviation from the steady-state mode.
CHAPTER ONE
INTRODUCTION
• Background of Study
Electric power system analysis software ran on mainframe computers in the early years after the introduction of digital computers.
Although there are many software applications in the market today that performs the analysis of electric power system on PCs, most are intended for professionals. These programs take detailed input data about the system, use fast algorithms to perform the solutions, and then present the result obtained. Such software is most useful when only the final results are sufficient for the user.
A problem for electric power system students is the solution of problems in textbooks. In the case of load flow problems, most of the effort is focused on iterative calculation, not on how the problem is solved. The same is true for stability studies. Professional software for analysis of electric power systems can help such students to prove their solution; however, only the validity of the final result can be checked.
The transient stability is a fast phenomenon and usually occurring within 1sec for a generation close to the cause of disturbance. The time domain simulation method is the most commonly used method to solve the set of non linear equations describing the system dynamic equation, in order to determine the transient stability. From the inspection of the solution, conclusion can be drawn whether the system is stable or unstable.
1.2 THE SCOPE OF THE PROJECT
In this project we the student should be able to know the operation and working rules of a computer based analysis for the purpose of stability studies. How it is developed, the interface with java language for efficient and accurate output result and its need in electrical power system field.
1.3 OBLIGATION OF THE PROJECT
The requirement and aims of this project work is to develop a java language program that can be use in a computer based analysis of electrical power system for the purpose of stability studies.
1.4 SIGNIFICANCE OF THE PROJECT
Java is most important in the current IT sector, because java is platform independent that means a program written in java language can execute on any platform, any machine architecture, any operating system which helps you to save the time by not modifying the code every time on every machine you use. Also java is one of the most popular programming languages used to create web applications and platforms. It was designed for flexibility, allowing developers to write code that would run on any machine, regardless of architecture or platform.
1.5 CONCEPT OF POWER SYSTEM STABILITY
1.5.1 Definition of Power System Stability
Power system stability can be defined as the ability of the power system to return to steady state without losing synchronism. Power is generated by synchronous generators that operate in synchronism with the rest of the system. A generator is synchronized with a bus when both of them have same frequency, voltage and phase sequence.
1.6 Classification of Power System Stability
1.6.1 Steady State Stability
These studies are restricted to small and gradual changes in the system operation conditions. In this, we basically concentrate on restricting the bus voltages close to their normal values. We also ensure that phase angles between two buses are not too large and check for the overloading of the power equipment, and transmission lines. These checks are usually done using power flow studies (CIGRE Report, 2011).
1.6.2 Transient Stability
From (IEEE, 2012), this involves the study of the power system following a major disturbance. Following a large disturbance, the synchronous alternator the machine power (load) angle changes due to sudden acceleration of the rotor shaft. The objective of the transient stability is to ascertain whether the load angle returns to a steady state value following the clearance of the disturbance.
1.6.3 Dynamic Stability
This is the ability of a power system to maintain stability under continuous small disturbance. This small disturbance occurs due to random fluctuations in loads and generation levels. In an interconnected power system, these random variations can lead catastrophic failure as this may force the rotor angle to increase steadily.
