The main contribution of this thesis is an investigation of the consequences of a previously undo... more The main contribution of this thesis is an investigation of the consequences of a previously undocumented accident scenario in the concentrated solar power plant literature; a full-bore pipe rupture resulting from a loss of flow event. Furthermore, given that the various failure modes leading to the aforementioned outcome were also uncovered, an approximation for the probability of occurrence was also acquired. After due consideration, the foremost accident scenarios were determined to be a fireball and a vapour cloud explosion. It was found that both have the capacity to cause harm to on-site personnel. However, in the fireball scenario, a lack of structural outdoor activity during operating hours reduces the exposure to personnel at the wrong place at the wrong time, while the distance of the building types with high occupancy rates to the foremost vapour cloud ignition source, the switchyard, results in an overall low probability of fatalities due to overpressure. Finally, with regard to the ignition sources, it was uncovered that although a thermodynamic analysis of the stagnation temperature in the heat collection elements revealed that it may exceed the autoignition temperature, such an event is unlikely due to material restrictions. That is, the pressure build-up as a result of thermal expansion is likely to result in a piping failure at much lower temperatures. Consequently, the most likely ignition sources for a fireball were found to be the red hot bearings resulting from a rotary joint failure and electrical spark ignition due to malfunctioning electrical wiring and/or systems.
ABSTRACT The capacity credit is often erroneously considered to be a time-invariant quantity. A m... more ABSTRACT The capacity credit is often erroneously considered to be a time-invariant quantity. A multi-year analysis of the incident wind profile of various potential wind sites uncovered that there exist large differences between annual capacity credit figures. The uniformity of these capacity credit figures is found to decrease with diminishing wind time series interval lengths. In recognition of the resulting uncertainty, decision maker risk propensity toward various capacity credit scenarios was investigated by adopting cumulative prospect theory. The methodology proposed in this paper is an extension of the effective load carrying capability method. It enables the quantitative analysis of the attitudes of decision makers with regard to deviations (gains and losses) from the forecasted capacity credit as a result of the uncertainty of the incident wind profile. Here, gains and losses may not be viewed by decision makers as having equal but opposite effects on the appeal of wind power production. Therefore, it is argued that a decision maker will not have a neutral risk propensity toward changes to the outcome of the capacity credit and will discount increases and decreases of the loss of load expectation according to a non-linear preference. In line with the well-known adagium that losses loom larger than gains the value of the capacity credit is found to be lower than its corresponding least squares forecast.
In this paper an attempt was made to introduce the concept of cyber security as applied in the el... more In this paper an attempt was made to introduce the concept of cyber security as applied in the electric power production and distribution infrastructure. Initially, the relevant control systems, threats to their continued safe operation and potential consequences are identified for both individual power plants and the power grid as a whole. Subsequently, the quantitative risk assessment of the aforementioned critical infrastructures is demonstrated by means of a methodology utilising attack trees. Here, is was established that introducing a package of relatively simple countermeasures may improve the overall system vulnerability of a power control system by as much as 45%.
The main contribution of this thesis is an investigation of the consequences of a previously undo... more The main contribution of this thesis is an investigation of the consequences of a previously undocumented accident scenario in the concentrated solar power plant literature; a full-bore pipe rupture resulting from a loss of flow event. Furthermore, given that the various failure modes leading to the aforementioned outcome were also uncovered, an approximation for the probability of occurrence was also acquired. After due consideration, the foremost accident scenarios were determined to be a fireball and a vapour cloud explosion. It was found that both have the capacity to cause harm to on-site personnel. However, in the fireball scenario, a lack of structural outdoor activity during operating hours reduces the exposure to personnel at the wrong place at the wrong time, while the distance of the building types with high occupancy rates to the foremost vapour cloud ignition source, the switchyard, results in an overall low probability of fatalities due to overpressure. Finally, with regard to the ignition sources, it was uncovered that although a thermodynamic analysis of the stagnation temperature in the heat collection elements revealed that it may exceed the autoignition temperature, such an event is unlikely due to material restrictions. That is, the pressure build-up as a result of thermal expansion is likely to result in a piping failure at much lower temperatures. Consequently, the most likely ignition sources for a fireball were found to be the red hot bearings resulting from a rotary joint failure and electrical spark ignition due to malfunctioning electrical wiring and/or systems.
ABSTRACT The capacity credit is often erroneously considered to be a time-invariant quantity. A m... more ABSTRACT The capacity credit is often erroneously considered to be a time-invariant quantity. A multi-year analysis of the incident wind profile of various potential wind sites uncovered that there exist large differences between annual capacity credit figures. The uniformity of these capacity credit figures is found to decrease with diminishing wind time series interval lengths. In recognition of the resulting uncertainty, decision maker risk propensity toward various capacity credit scenarios was investigated by adopting cumulative prospect theory. The methodology proposed in this paper is an extension of the effective load carrying capability method. It enables the quantitative analysis of the attitudes of decision makers with regard to deviations (gains and losses) from the forecasted capacity credit as a result of the uncertainty of the incident wind profile. Here, gains and losses may not be viewed by decision makers as having equal but opposite effects on the appeal of wind power production. Therefore, it is argued that a decision maker will not have a neutral risk propensity toward changes to the outcome of the capacity credit and will discount increases and decreases of the loss of load expectation according to a non-linear preference. In line with the well-known adagium that losses loom larger than gains the value of the capacity credit is found to be lower than its corresponding least squares forecast.
In this paper an attempt was made to introduce the concept of cyber security as applied in the el... more In this paper an attempt was made to introduce the concept of cyber security as applied in the electric power production and distribution infrastructure. Initially, the relevant control systems, threats to their continued safe operation and potential consequences are identified for both individual power plants and the power grid as a whole. Subsequently, the quantitative risk assessment of the aforementioned critical infrastructures is demonstrated by means of a methodology utilising attack trees. Here, is was established that introducing a package of relatively simple countermeasures may improve the overall system vulnerability of a power control system by as much as 45%.
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