Electric equipment, costs power factor

Power factor is included in the discussion of power quality for several reasons. Power factor is a power quality issue in that low power factor can sometimes cause equipment to fail. In many instances, the cost of low power factor can be high utilities penalize facilities that have low power factor because they find it difficult to meet the resulting demands for electrical energy. The study of power quality is about optimizing the performance of the power system at the lowest possible operating cost. Power factor is definitely an issue that qualifies on both counts. 

Power factors in industrial plants are usually low due to the inductive or reactive nature of induction motors, transformers, hinting, and certain other industrial process equipment. Low power factor is costly and requires an electric utility to transmit more total KVA than woxdd be required with an improved power factor. Low power factor also reduces the amount of real power that a plant s electrical distribution system can handle, and increased line ciurents will increase losses in a plant s distribution system. 

Recently there has been growing interest in power factor correction circuitry. Power factor, which is defined as the ratio of the apparent required power to the actual true power, ultimately affects the circuit s efficiency, thus varying the cost of electricity. It seems that almost all AC-powered equipment now require some form of active power factor correction in order to operate efficiently. Active power factor correction utilizes electronics to force the input current to look like a... 

An important result of this study is the finding that the work and pressure of compression or extrusion can be reduced by a factor of about two by preheating the feedstock to 200-225 C before densification, This requires extra thermal energy for complete drying and to heat the biomass (heat capacity about 1.8 J/g-C) to the higher temperature however, these are offset by lower electrical power costs, lower equipment costs because of the lower pressure requirements, possibly reduced die wear due to improved lubricity of the biomass at increased temperatures, and increased fuel value due to complete water removal and prepyrolysis. These factors must be tested at the commercial scale before any conclusions can be drawn on the desirability of preheating feedstock. 

The annual cost of operating a vacuum system is several times the equipment cost. So, a detailed review of the operating cost of a vacuum system is essential. For example, use of chilled water instead of cooling water can reduce steam/power consumption of the vacuum system. It also eliminates cavitation problems associated with LRVPs used at low suction pressures. Although chilled water is costlier than cooling water, it can be attractive if the electricity price is low or waste heat is available for chilled water production. Selection of SJE, LRVP, DVP, SJE-LRVP or SJE-DVP combination depends on many factors listed in Table 11.1. 

The electrical supply equipment is the second biggest equipment package after the mechanical equipment. The package includes the transformer/rectifier (T/R) sets and bus bars for providing DC power to the cells, the associated power factor correction equipment and harmonics filtration equipment, and the service transformers and circuitry. This equipment will typically comprise about 15 - 25 % of the cellhouse cost. The cost is heavily influenced by whether or not an electrical substation is included, and by the redundancy requirements for the T/R sets. A plant can choose to have no spare T/R capacity, partial redundancy, or full redundancy. Such cost savings must be weighed against the cost of lost production when a T/R set fails. 

A complete discussion of the benefits of modern electrical systems over their predecessors is out of the scope of this paper. However, several major benefits of modern AC drive systems will be briefly outlined. A modern AC drive system is capable of being operated at unity power factor, or even leading power factor to provide power factor correction to the remainder of the hoist plant. The performance is far superior to previous DC drive systems whose power factor is dependent on speed, ranging from 0.1 to 0.8 during a typical duty cycle. The improved power factor will result in significant savings in electricity cost, and in power factor correction equipment that may otherwise be required. 

Unique operating characteristics of fuel cell power plants are as follows. Beneficial operating characteristics of fuel cells saves cost and other benefits include load following, power factor correction, quick response to generating unit outages, control of distribution line voltage and quality control can control real and reactive power independently control of power factor, line voltage and frequency can minimize transmission losses, reduce requirement for reserve capacity and auxiliary electric equipment fuel cells have an excellent part load heat rate and can respond to transmission loads. 

Electrical power must be supplied for lighting, motors, and various pro-cess-equipment demands. These direct-power requirements should be increased by a factor of 1.1 to 1.25 to allow for line losses and contingencies. As a rough approximation, utility costs for ordinary chemical processes amount to 10 to 20 percent of the total product cost. 

The main cost factors are represented by equipment depreciation, membrane replacement, and electric power consumption. The other costs (man power and water consumption) are of minor influence. Membrane filtration plants equipped with a low level of automation require only a few hours of attention and direct surveillance by the operator per day. Direct surveillance of membrane filtration equipment is necessary at times when batches need to be changed or during membrane cleaning. The electric power consumption is associated with the use of pumps to move the viscous yeast slurry over the membrane surface, and its estimation is relatively straight forward. 

We will instead discuss the issues beyond the design of the mechanical and process equipment, which can have significant effects on capital and operating costs. Some important differences between a greenfield and brownfield project are presented, followed by key considerations during site selection. The major components of capital cost are discussed, with emphasis on electrical power and the design of the cellhouse building. Finally, the factors that affect the project schedule are discussed. 

Power conversion system. The cost of the AHTR power conversion system is scaled based on PCU power densities from detailed UCB design studies shown in Table 8.2, from the cost of a set of GT-MHR PCUs capable of producing 1145 MW(e), using a scaling exponent of 0.86. The PCU costs are scaled further by a factor of 0.9 to account for the fact that they are not nuclear-grade equipment in the AHTR. The costs of the electrical plant and the heat rejection equipment are scaled with electrical power (0.86 exponent) and thermal heat rejection (also 0.86 exponent), respectively. 

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