Abdullah Asuhaimi Mohd Zin, Senior Member, IEEE, and Sazali P. Abdul Karim
Abstract—Unplanned electrical power outages are a major concern to power utilities throughout the whole world. Unfortunately,power outages will continue to occur and they cannot be fully prevented.It could be the result of lightning strikes, tree encroachment,or equipment failure. However, the impact can be reducedif power system operators are equipped with the appropriate tools to analyze the root cause of the failure. Without sufficient tools to identify the nature of a fault, the restoration process could be delayed because the operator does not know whether it is safe to normalize the isolated line. This paper describes the new and simplified fault signature analysis approach on Tenaga Nasional Berhad using a digital fault recorder. The research focuses on the contribution of the lightning strike and tree encroachment to the overhead line tripping in Malaysia.Index Terms—Blackout, digital fault recorder (DFR), fault signature analysis (FSA).
THESE DAYS, the requirement of an uninterrupted power supply has become a regulation imposed by governments to the power utilities throughout the whole world. Electricity is no longer a luxury item. It was an essential commodity, which has now become an economic and security issue. Power outages and blackouts have become more painful in our daily lives and routine activities in this challenging 21st century.In 2003, the world experienced at least five major electrical power blackouts affecting a fewcountries either partially or total national blackouts. The famous wide-scale power outages are as follows.
1) August 14, 2003 at 16:10 h, Northeastern U.S. and Central Canada –.
2) August 28, 2003 at 18:26 h, Central U.K. –
3) September 1, 2003 at 09:58 h, Northern Malaysia .
4) September 23, 2003 at 12:35 h, Eastern Denmark and South Sweden –.
5) September 28, 2003 at 03:28 h, entire nation of Italy and South Switzerland –.
All of those blackouts caused great financial losses that were estimated to be more than 1 $U.S. billion . Blackouts can be initiated for so many reasons, including the demand was not balanced with the generation output, the failure in protectionsystem, wrong or slow decision making made by the system operator, and so forth. In general, the blackouts are due to a combination of circumstances that stress the network beyond
its limits. The most difficult part is to seek solutions that will prevent such cascading of tripping that lead to a partial or even total national blackout.During any system fault on an overhead line, power system operators do not know the cause of the tripping immediately after the incident has occurred. This is because they have to dispatch the maintenance crew to walk along the overhead line using the fault-location equipment to identify the reason of the flashover. However, if the incident occurs at night, they either have to wait until the next morning and leave the line on outage or try to close back the line based on their own judgment. On the other hand, if they have been equipped with the fault signature analysis (FSA), they can normalize the isolated line immediately without having to wait for the maintenance crew to identify the cause of the tripping.
The use of FSA in TNB is a new approach introduced through a research collaboration between TNB and the Universiti Teknologi Malaysia (UTM). The objective of this FSA is to equip the system operators with an appropriate tool to understand the fault initiation during decision making. Before the application of FSA, the decision making was based entirely on relay operations captured by the SCADA system , . Moreover, the information from SCADA sometimes does not provide the system operators with meaningful
information. Therefore, the system operators are subjected to many uncertainties and this could lead to an incorrect analysis. The consequences of this action could be detrimental to the system security which might lead to a cascading operation. The benefits of FSA have been proven in the efficiency during the
decision-making process. After implementing the new FSA, the decision-making process has become much easier and faster without any doubt. As a result, TNB has reduced the operational cost for each tripping that occurs in the grid system.