Research Publications

A O Ibe

A Travelling Wave-Based Fault Locator for Two- and Three-Terminal Networks

A O Ibe; B J Cory  1986

The high frequency components in fault waveforms present undesirable effects to most fault location algorithms and as a consequence filtering of postfault signals, to remove the high frequency transients, is essential for accurate fault location. A fault location algorithm that derives from travelling wave principles can cope with high frequency transients since these basically depend on travelling wave phenomena. The development of such an algorithm is the objective of this paper. Using the telegraph equations as a line model, voltage and current samples taken at one end of a line within the first 5 ms of fault inception are used to generate instantaneous voltage and current profiles for the rest of the transmission line. The voltage and current estimation is based on the solution of the equations of the line model by the method of characteristics. Criteria functions involving any of the square of the voltage, the square of the current, or the product of the two are applied for determination of the fault position. Fault position is given by the peak variation in tangent to the above basic functions. The algorithm finds application in fault location on two and three-terminal networks at both transmission and distribution levels.




Fault-location algorithm for multiphase power lines

A O Ibe; B J Cory  1986

Improved mathematical models of transmission lines are used to develop a fault location method which copes with high-frequency transients. The telegraph equations used for a line model are solved by the method of characteristics using voltage and current samples as boundary conditions taken at one end of the line within the first few milliseconds of fault inception. Estimates of voltage and current profiles for the entire length of the transmission line during the fault are obtained. Criteria for fault location are based on a formulation involving these voltage and current estimates. For fault location on multiphase systems the concept of modal analysis is used in enhancing the fault-locating capability of this algorithm.





A Critical Review of Grid Operations in Nigeria.


A.O. Ibe, and E.K. Okedu, 2009


The grid is a network that connects all the major power stations and load centers in a country (or power system). The constraints to grid operations include generation, transmission, and system control. Remedial actions aimed at addressing these problems are presented. The high point of the recommendations is the adoption of “Distributed Generation Scheme”. In the absence of an accurate load demand, regional sales of electric energy were used to estimate regional demand for electricity. These were in turn used to decide location of new generating plants under the distributed generation scheme.


(Keywords: grid operations, energy sales, distributed generation)





A.O. Ibe, N.O. Ogbogu and A. Akhikpemelo 2010


Consumers of electrical energy expect a network to support their apparatuses with continuous and reliable supply.This makes reliability studies an  important task besides all the other analyses required for assessing the system performance. The paper presents an analytical approach in the reliability assessment of the Port Harcourt 33/11kV power distribution system. The assessment was performed with the 2009 power outage data collected from the monopolistic operator of the Nigerian power system, National Electric Power Authority (now unbundled and called Power Holding Company of Nigeria, (PHCN) Plc) on the four substations: Marine-Base, U.S.T., Old-GRA and PH-Town injection substations radiating from the Port Harcourt Town 132/33/11kV transmission/injection substation. Thus, this study will enable utilities to determine the state of reliability of each substation and hence, provide a standard for prioritizing maintenance and upgrade of its distribution substation facilities.


Keywords: Electrical distribution system, reliability, analytical assessment, reliability indices, ETAP 





AO Ibe 1996



Transients in power systems are initiated by abrupt changes to otherwise steady operating conditions. These changes would be as a result of any of the following: opening or closing of circuit breakers, switching conditions, lightning or any other fault condition. For purposes of power system analysis these conditions are simulated using mathematical models. In the formulation of these mathematical models efforts are made to represent changes in transmission line characteristics, such as the variation of line parameters with frequency.

Electromagnetic (EM) transients produced by these mathematical models serve as a useful reference in the design of protective devices and fault locators. It is therefore pertinent to examine the effect of faithful reproduction of line characteristics in the simulated transients with respect to the performance of fault locators tested with the simulated transients. Such investigation has shown that the computational burden involved in trying to represent all line characteristics in transients calculations could be saved.





Assessment of Electrical Energy Demand in Nigeria.: Electricity Demand Projection in Nigeria Using Box-Jenkins and Simple Exponential Forecasting Techniques.

by Kenneth Eloghene Okedu, A.O. Ibe (2010)

The importance of forecasting in the electricity industry cannot be over emphasized. It is one of the most important planning tools that helps in the assessment and prediction of future power demand. Unfortunately precise forecasting is impossible and to tie the future plans too rigidly to future projection or forecast, no matter how sophisticated, is to risk costly mistakes. The simple exponential smoothing model and the box-Jenkins model are used to forecast electricity demand in Nigeria for the next twenty years. The high accuracy of the techniques is demonstrated by doing a forecast for past years and comparing the result with figures obtained from Power Company of Nigeria.




Transient Stability Assessment of the Nigerian 330kV Network


Anthony O. Ibe, Ameze Odia 2010


Transient stability limit of the Nigerian 330kV power system was assessed in terms of its ability to maintain synchronism among the generating units. The Power (angle) stability limit and voltage stability limit, before, during and after system changes or disturbances were also assessed. The 330kV transmission network was analyzed using the Runge Kutta Method to determine the critical clearing angle and the corresponding critical clearing time. It was observed that a critical clearing angle of 12.85 with critical clearing time of 0.1s gave a more stable result than a critical clearing angle of 166.376 with a corresponding critical clearing time of 0.363s. It was therefore recommended that faults on the network be cleared as quickly as possible so as to maintain the system stability.

Keywords: Power (angle) stability limit, voltage stability limit, synchronism, 330kV Power System, Runge Kutta Method.




Electric power supply in an offshore oil production platform

A.O. Ibe 2003



A study of the provision of electric power using associated natural gas as primary source of energy, in an offshore oil production platform has been carried out. Some of the problems to be contended with include: the effects of impurities contained in the fuel gas supply; variations in the production process characteristics; space constraints and the fire hazards that exist in an oil production environment. The study revealed that power supply can be improved by modifying fuel gas supply manifold, and also by introducing multiple stage gas filtration units and neutralizer filter units. Finally, among other recommendations, it will be desirable to replace the battery-powered UPS system with a rotary engine UPS which can provide long-term power supply back-up as well as the benefits of rotating machines.

KEY WORDS: Offshore, Platform, Power Supply, Gas turbine, Rotary Diesel UPS.






Ibe A.O, Oke M. J., Esobinenwu C.S. 2015



Access to electricity in the riverine areas of rivers state is very poor. The area is mostly off grid as a result of the Intricacy in extending the national grid through its difficult mangrove swamp terrain. This study investigated potential sources of energy in the riverine areas and to find out the cost effective off-grid option in meeting their electricity needs. Onsite visitations and observations, wind speed measurements using anemometer, and literatures show that the area is home to hydro resources, with average wind speed of about 7.22m/s at the coast line, and solar radiation of 4.39kWh/m2. A linear optimization model of a power system to meet a local demand was simulated using HOMER software with a view of solar, wind and diesel energy resources. The result revealed that the optimal configuration option among ten feasible options is a hybrid wind/diesel/battery system. The least cost of electricity is 22.21N/kWh while the diesel generator which is the existing system was higher at 108.72N/kWh. The result also showed that adding renewable energy fraction to the existing diesel system was seen to be economical at 20% fraction and above. In the light of these, access to electricity in the riverine areas of rivers state can be greatly increase by harnessing available renewable energy resources in the area for off grid electrification with backup from diesel generator pending sufficient power from the national grid and subsequent extension.

KEYWORDS: Off grid power system solutions, Riverine Areas of Rivers State, Renewable Energy



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