Power System analysis

This paper presents an effective algorithm to locate Single Line to Ground (SLG) fault at a transmission line. Post fault voltages and currents from both substation terminals were
used as the input parameters to the algorithm. Discrete Fourier Transform (DFT) was used to extract the magnitudes and phase angles of three phase voltages and currents. The modeling of the transmission line along with the algorithm was performed using Matlab/Simulink package. The results of fault location for SLG faults along the transmission line demonstrated the validity of the algorithm used even for high resistance earth fault.

This article details a new transfer function approach in passive harmonic filter design for industrial and commercial power system applications. Filter placement along with six common filter configurations are presented. Harmonic impedance, voltage division and current division transfer functions are derived and used in a practical filter design procedure that incorporates IEEE-519 distortion limits directly into the design and component

Renewable energies based on wind farms and solar PV have proven to be a good complement to conventional energies based on fuel and nuclear energy mainly. Despite the reasonable desire of having future electricity generation based exclusively on renewable energies, this should be considered more a desire than a technically achievable goal. The challenges of having a stable grid that meets all the security and reliability requirements necessary for a grid operation similar to those achieved with conventional energies are for the moment insurmountable and the most likely in the near future is to have a mixed electricity network composed of conventional energies that use fuels with the minimum environmental impact, such as nuclear or hydrogen-based energy as two examples, serving as the main support for the stability and security of the system, and renewable energies based on wind and sun, which cover most of the future energy needs. Although this is not an article dedicated to the analysis of the advantages or disadvantages of one or another energy solution, it starts from the premise of accepting that the mixed solution mentioned above will be the one that prevails in the future and any analysis of the impact on the different elements of the electricity system should consider these assumptions.
Most line distance protection schemes assume that the system will always be able to supply enough short circuit current to make the relays trip. However, there are scenarios in transmission systems where we could have a strong source on one end of a transmission line and a weak source on the other (weak infeed). The fault current infeed at one line end may be so low that it is insufficient to operate any of the distance zones and the pilot schemes (overreach or blocking) will not operate the way we would expect them to.
One scenario where a weak infeed (WI) exist is the case of a line end open, or renewable generation based on wind or PV solar at the weak end. A WI condition is usually present because of the behavior of renewable generation during short circuits. Low current values are associated with large source impedances that affect the reach and behavior of the distance relays.
The conventional WI schemes assume no operation of the forward and reverse distance functions in the weak source of the line and under this condition, the relays are not able to send any signal to the other end. To overcome this situation (as the relays in the strong source are supposed to operate), a permissive tripping signal is sent from the strong end to the remote one (weak source). The remote source with the conditions mentioned above (no operation of any distance unit) resends the permissive tripping signal to the strong end (ECHO), allowing the operation of the permissive or blocking scheme in the strong end. Usually, the weak end is tripped with the reception of the permissive tripping signal (in permissive tripping schemes) plus a WI condition defined by the user (Undervoltage condition or no operation of any protection function).

Power transmission is a major issue in Electrical Engineering after Power generation. Fault in transmission lines is common and major problem to deal with in this stream. This paper presents a technique to detect the location of the different faults on a transmission lines for quick and reliable operation of protection schemes. The simulation is developed in MATLAB to generate the fundamental component of the transient voltage and current. MATLAB software is used to simulate different operating and fault conditions on high voltage transmission line, namely single phase to ground fault, line to line fault, double line to ground and three phase short circuit. Effects of variations in the fault resistance (Rf), distance to fault (Lf) have been studied broadly on the voltage, current and its relation to impedance of the system which creates the logic for detection, classification and location of faults.

Engineering process for implementing of substation automation using IEC61850 standard requires both the knowledge of using various software tools and appreciation of concepts associated to Information and Communication Technology (ICT). Basically, these have been the main reasons for many utilities worldwide to delay the implementation of IEC61850 standard as there is still a lack of knowledgeable users within the power engineering industry who are specialized in these software tools. Having considered the above facts, the main purpose of this paper is to design and implement of substation automation laboratory using IEC61850 standard which can be used as a testing and training facility for both power engineers and power engineering students. The proposed methodology is to design and implement a model zone substation automation system (SAS) according to the arrangements of a real terminal zone substation as exists in Victoria State's terminal zone substations. The significance of the project can be highlighted in its contribution for providing real-world simulation of SAS for education and training purposes. Moreover, as the extension on IEC61850 standard continues to cover different domains in power systems automation, there is always a need for laboratory facilities for verification of the results related to research on IEC61850 standard.

The basis of comprehension of power-flow problems obtained from lectures, lecture slides and subject book. Circuit built and simulated in the Power World program, and then the analytical solution obtained using the theoretical knowledge. Finally, both answers were compared with each other and the difference in the figures were deducted and discussed elaborately.

Power transmission is a major issue in Electrical Engineering after Power generation. Fault in transmission lines is common and major problem to deal with in this stream. This paper presents a technique to detect the location of the different faults on a transmission lines for quick and reliable operation of protection schemes. The simulation is developed in MATLAB to generate the fundamental component of the transient voltage and current. MATLAB software is used to simulate different operating and fault conditions on high voltage transmission line, namely single phase to ground fault, line to line fault, double line to ground and three phase short circuit. Effects of variations in the fault resistance (Rf), distance to fault (Lf) have been studied broadly on the voltage, current and its relation to impedance of the system which creates the logic for detection, classification and location of faults.

Power transmission is a major issue in Electrical Engineering after Power generation. Fault in transmission lines is
common and major problem to deal with in this stream. This paper presents a technique to detect the location of the different faults on
a transmission lines for quick and reliable operation of protection schemes. The simulation is developed in MATLAB to generate the
fundamental component of the transient voltage and current. MATLAB software is used to simulate different operating and fault
conditions on high voltage transmission line, namely single phase to ground fault, line to line fault, double line to ground and three
phase short circuit. Effects of variations in the fault resistance (Rf), distance to fault (Lf) have been studied broadly on the voltage,
current and its relation to impedance of the system which creates the logic for detection, classification and location of faults.

Improved and controlled power quality is one of the essential and fundamental need in any power driven industry for optimum utilization of resources. However critical problems in power quality have been recognized such as sags, swells, harmonic distortions and other interruptions. Out of these sags and swells are predominantly found and have severe impact on the electrical devices or electrical machines and therefore needs to be compensated at an earliest to ensure any mal-operation or failure. To crack these problems custom power devices are used like unified power-quality conditioner (UPQC), distribution-STATCOM (DSTATCOM) and dynamic voltage restorer (DVR). The DVR is a one of the custom power device used for the compensation of voltage sag and swell with an advantage of active/reactive power control. A major volume of literature reported in past several years on different configurations of DVR and different control technique used in it. In context of this a detailed review on DVR has been presented with different possible power circuit topologies and control techniques available to reconcile these power quality issues. This review article will contribute in better selection of control strategy and power circuit for optimum performance of DVR for a particular requirement. Also it presents a very helpful investigation for the researcher in this field.

The electrical power systems laboratory at the Palestine Technical University Kadoorie designed to directly apply theory learned in lectures to devices that will be studied in the laboratory. The Lab focuses on all aspects of electrical power systems: power generation, transmission and distribution lines, protection systems, electric power management systems and a wide range of electrical measurement systems. Research projects carried out in this laboratory include generation, transmission and distribution of electrical energy and all facilities that guarantee the safe supply of electrical energy. In addition to the monitoring, control and supervision systems that are studied and followed in this laboratory.

The laboratory course is intended to provide practical understanding of power system operation, control and protection. The main goal is to enable students to apply and test theoretical knowledge they mastered in previous years of studies. The laboratory course enables them to develop practical skills in various fields of power engineering in a controlled environment.

The aim of this laboratory work is to use the Newton-Raphson power flow method, theoretically solve the bus admittance matrix (Ybus), initial mismatch conditions of ΔP2(0) and ΔP3(0), and all Jacobian elements. Finally, these results have to be compared with the simulated results.

This presentation is based on a study conducted in October-November 2004. It was meant to form the database for comprehensive reactivation of the power system protection scheme in the Ajaokuta Steel Company (ASCO) power plant and its connected network with a view to establishing an effective and workable power supply to the entire plant. To establish this requirement, the entire system configuration is closely investigated vis-à-vis standard requirements for effective operation of the power system. This is viewed from the premise of standard protection principles and practice that positively impact on the network under consideration, available schemes and its effect on the present installation as well as required solutions to short-comings observed in the existing system.

The purpose of this experiment is to investigate one-line diagrams, the power system representation in per-phase, per-unit equivalent circuits as well as node equations for these equivalent circuits. The experimental circuit is then constructed in PowerWorld simulator.

Evolving from the era of British Standards Specifications to multiplicity of standards, Electricity Industry in Nigeria has witnessed very negative transformations. Efforts of engineers to address the matter over the years has not yielded any dividend because control of equipment specifications for the electricity industry is beyond the control of the engineering community. In this write-up, we have tried as much as possible to take an in-dept look at Transformer Vector Group abuse in Nigeria and its attendant consequences on the entire Power System. Efforts have also been made to address multiple cases of transformers introduced into the system with a view to correct the power system anomalies. Background: One of the key areas of the supply industry that needs conformance to required standard include the ever-elusive power system stability and power quality, and the matter of Transformer Vector Group may be part of the problems. Efforts by the Nigerian Electricity Management Services Agency (NEMSA) in recent years to address this has not really yielded positive result because engineers themselves are still battling with the matter of power availability to think of and understanding other critical areas of Power System Engineering. We are still trying to understand this controversy over transformer vector group and its effect on the power system, denying NEMSA the much-needed voice for this crusade. Materials and Methods: We have endeavored in this article to take a close look at the Nigerian National Grid in terms of the Distribution Sub-sector and Network integration with a view to addressing issues that can create instability in the 132/33kV Sub-transmission system. To achieve this, the problem of the Nigerian National Grid is reviewed through standard Network Configuration requirement from Generation through Transmission to Distribution Electricity Networks, evaluating the attendant issues, analyzing transformer Vector Group abuse and addressing the technical implications. Results: The investigation revealed some instability introduced into the Electric Power System with the installation of non-standard transformers and these include unavoidable phase-shifts that cause error when trying to determine the true power consumption, results in deviation of actual power-factor and Real Power delivered, Negative Power Factor that produces reverse power flow in the system and possible over-voltages, the effects of the harmonic currents that results in additional copper losses, Increased core losses, Increased electromagnetic interference, as well as Resonance between winding reactance and feeder capacitance. The conclusive results show about 35,138.88Kwhr energy deficit per month and 421,666.56Kwhr per year for a 500KVA transformer operating at 24 0 phase-shift due to introduction of Dy11 Power Transformer in the 33/11kV Network. Conclusion: It is concluded that outright ban of such installation is the basic solution to this problem and in cases that are already in the system, internal or external vector re-configuration is recommended.

Los participantes en este entrenamiento disfrutarán de una experiencia de aprendizaje única, en la cual se presenta una introducción exhaustiva e integral de las funciones básicas de software DIgSILENT PowerFactory.

El participante de este entrenamiento obtendrá una visión  completa de las principales funcionalidades del programa de DIgSILENT PowerFactory.

This paper describes the modeling of distance relay using Matlab/Simulink package. SimPowerSystem toolbox was used for detailed modeling of distance relay, transmission line and fault simulation. Inside the modeling, single line to ground (SLG) fault was choose to be the fault type and Mho type distance characteristic was choose to be as the protection scheme. A graphical user interface (GUI) was created using GUI package inside Matlab for the developed model. With the interactive environment of graphical user interface, the difficulties in teaching of distance relay for undergraduate students can be eliminated.

In conventional power flow, the system branch resistances are assumed to be constant despite the fact that they are sensitive to temperature, and therefore to branch loading and losses. When the accurate calculation of losses is important, temperature correction of branch resistance can improve the accuracy of the power flow calculation. This paper introduces a temperature-dependent power flow algorithm: a novel approach which integrates an estimate of branch temperatures and resistances with the conventional power flow equations. This methodology relies on the creation of a set of coupled temperature and power flow equations which are solved using the Newton-Raphson solution method for nonlinear equations. The core methodology is developed first, then extended via several decoupling techniques.

Güç sistemlerinde enerji üretim maliyeti minimum olması gereken en önemli faktördür. Rekabetçi piyasa koşulları, enerji verimliliği, fosil yakıtların tükeniyor ve giderek pahalılaşıyor olması ile çevresel kaygılar bu faktörü olabildiğince minimum yapma gereksiniminin en önemli nedenleridir. Bu nedenle eldeki santrallerin minimum maliyet ve maksimum fayda anlayışı içerisinde talep edilen yük miktarını karşılaması gerekmektedir. Bu çalışmada da bu anlayışı sağlayabilmek için verilen 40 jeneratörlü bir sistemde diferansiyel gelişim optimizasyonu ile ekonomik yük dağıtımı yapılmıştır.

In this paper, the features and flexibilities of an analysis and visualization tool, MatSim, are presented. Using this tool we can carry out power flow, transient and small-signal stability analysis of large power systems on the widely used MATLAB environment. This tool facilitates easy visualization of complex power systems using a versatile single-line editor module which is also developed on the same platform as that of the MatSim. Such an integration not only simplifies the feeding in of enormous amounts of data required by the power system analysis software, but also permits displaying of power system analysis results in an interactive fashion on the one-line-diagram of the system using the inherent and powerful plot-handling features of the MATLAB. Since MATLAB is a widely used software, the tool offers an ideal choice for beginners as against any industry grade costly packages. The tool provides many dynamic models such as generators, load, various IEEE-suggested excitation, prime mover and power system stabilizer controllers, fault, line trip and perturb V ref models to create disturbances. The models are implemented with default standard parameters which facilitate easy experimentation with power system examples of any size including an SMIB system.

A new approach to the prediction of the reliability of electrical systems is presented. In this approach a graph trace based reliability analysis of electric transmission and/or distribution systems is used. The systems are modeled using containers with iterators, where the iterators manage graph edges and are used to process through the topology of the graph. The analysis provides a means of computationally handling dependent failure rates and cascading failures. The effects of weather, time-varying loads, equipment age, wetness, and dependent failures associated with repaired components are considered. A sequential Monte Carlo simulation is used to evaluate the reliability changes for different system configurations, including distributed generation and transmission lines. Historical weather records and loading are used to update the component failure rates on-the-fly. Simulation results are compared against historical reliability field measurements.