Shunt Compensation for Sululta-Addis South-II Transmission-Substation System
No Thumbnail Available
Date
2017-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
In an electrical power system, if there is no enough reactive power, the voltage decreases. Thus, it is not possible to push the power demand to loads through the lines and has a strong effect on system stability. To overcome such kind of problems, shunt compensation near or at the load area is one solution. Thus, the power system networks under this case study i.e.
Sululta-Addis south-II transmission-substation which routes North West to South East of Addis Ababa uses TSC to the compensation task. The power supply during the peak hour time comes from Debre Markos to Sululta via 1x400kV transmission line, from Ghedo to Geffersa through 2x230kV transmission line and from Sebeta-II to Sebeta-I through 2x230kV transmission lines. To evaluate the voltage profile of this region, investigations has been conducted and under voltage problem at bus terminals of the substation has been found, this leads to reduction of power transfer capability of the network to the load side and to mitigate the problem, shunt compensation using FACTS device family called Thyristor Switched Capacitor (TSC) is used. To complete the entire study, necessary system parameters and data have been collected, analyzed and simulation task using DIG SILENT Power Factory software has been done for a time of peak hour of the day which is found to be at 19:00. Result of the study shows, an improvement of voltage profile at bus terminal of the substations. For example, voltage at Derba-132kV bus bar is corrected from 0.91 to 1.00 per unit (pu) which is 9.9% improvement, at Mekanissa substation 15kV bus bar from 0.93pu to 0.99 pu which is 6.5%, at Addis South-II 132kV and 15kV bus bars from 0.88 to 0.96 pu and 0.89 to 0.95 pu which is an improvement of 9.09% and 6.7% respectively. Thus, the power transfer capability increases by 27.07MW.
In terms of cost benefit analysis, cost of compensation system is estimated to be 9,372,085.13 USD and a new 66kV transmission/substation which has a rating of 27MW costs 9,578,000.00USD. Thus, the compensation system can omit the constructing of new 66kV transmission/substation system and definitely cost of land compensation, project completion time and environmental crises will be reduced. So, these shall be considered for economic viability.
Keywords KeywordsKeywords Keywords : Shunt compensation, thyristor switched capacitor, power transfer capability, DIG SILENT Power Factory, voltage violation
Description
Keywords
Shunt Compensation, Thyristor Switched Capacitor, Power Transfer Capability, Dig Silent Power Factory, Voltage Violation