Electrical load dump

As with the electrical load profile, it is also necessary to analyze the heat load over the daily and annual cycles. Ideally, the heat load will match the available heat from the electrical generator (however, this is rarely the case). There will be periods when supplementary output will be necessary which can be achieved by, say, supplementary firing the waste heat gases of a gas turbine, or heat output reduction is necessary by the introduction of bypass stacks. For a steam turbine installation bypass pressure-reducing valves will be necessary to supplement steam output, while a dump condenser may be needed at low-process steam demands. The nature of the electrical and heat load will obviously have significant influence in the development of the scheme and scope of equipment. 

The development of vehicle electrical systems operating at a nominal 42 V and its standardization with ISO is underway. A working group of the European Vehicle Electric System Architecture Forum has prepared a draft standard for this new voltage level [58]. The 42-V level was chosen as a compromise between the demand for an increased voltage to achieve higher efficiency in electrical and electronic components and the exclusion of safety hazards, even under extreme operational conditions like load dump, etc. The term 42-V PowerNet , or simply PowerNet , is now established worldwide [9,11,59]. 

Associated with the control system was the dump condenser, which was a drum filled with tubes through which cold water flowed. The steam which passed into the drum was condensed by the cold tubes, and a valve enabled all or part of the steam from the boiler to be diverted to the dump condenser instead of going to the turbine. Thus the steam load of the boiler could be kept constant regardless of the electrical load and the reactor could continue to operate at full power even when the turbo alternators were idle. The dump condenser also enabled the turbines to be started and run up with the reactor at power. 

A dragline at Atlantic Richfield s Black Thunder strip mine in Gillette, Wyoming, loads coal into a dump truck. The coal is transported to cities around the country where it is burned to generate electricity. (Corbis-Bettmannj... 

The electrical and heat analysis, as discussed in Section 15.3, will show the relationship between power and heat and how this varies over time. It may be necessary to use steam bypass and stations or dump condenser, as discussed in Section 15.2. The uses of dump condensers for meeting part-load requirement is inefficient and should be avoided. It is more acceptable to reduce turbine power output accordingly and import or top-up from an alternative supply. 

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