Spare Generator

In practice if F, is too high the operator of the plant will become nervous and will often switch into service the spare generator. If F, is too low then there will be too many generators in service and it shonld be possible to withdraw one. Gas turbines have poor fuel economy when they are lightly loaded. 

If Fo is designed to be less than approximately 105% then the generators will be able to absorb the overload nntil some corrective action by an operator is taken e.g. pnts the spare generator into service. 

The supply capacity normally consists of two parts. One part to match the known or initial consumption and a second part to account for keeping a spare generator or feeder ready for service. 

Because there are problems in the building of Soviet PWRs due to the poor rate of production of reactor pressure vessels, the repercussions for the Soviet nuclear and electricity generating capacity will be serious for several years. There is little spare generating capacity in the Soviet Union. 

Usually, major pumps are spared, even if the philosophy of shutting down an entire train is adopted. Other spares or bypasses are often left out for such a philosophy, but standard bypasses (control valves, major block valves, etc.) are normally included otherwise. The utility area will have normal sparing (for example, three 3-capacity electric generators), even if train shutdown philosophy dictates the process area. 

The reset should be resonant to reduee the amount of noise that eould be generated by the rapid diseharge of the elamp eapaeitor. An induetor of about 2 to 3 uH is useful. An etehed printed eireuit board spiral induetor ean also be used for this purpose, if the spaee ean be spared. Sinee the average eurrent is small, the traee need be only about 10 to 20 mils (0.25 to 0.5 mm) in width. Three spiraled turns produee about the induetanee needed. 

Now let us consider utility failure as a cause of overpressure. Failure of the utility supphes (e.g., electric power, cooling water, steam, instrument air or instrument power, or fuel) to refinery plant facihties wiU in many instances result in emergency conditions with potential for overpressuring equipment. Although utility supply systems are designed for reliability by the appropriate selection of multiple generation and distribution systems, spare equipment, backup systems, etc., the possibility of failure still remains. Possible failure mechanisms of each utility must, therefore, be examined and evaluated to determine the associated requirements for overpressure protection. The basic rules for these considerations are as follows ... 

While you may not service your products, others may well do so and the standard requires that you collect information generated by the servicing organizations and convey it to those who can use it to improve the product and the manufacturing processes. This means that you will need to establish liaison links with servicing organizations and enlist their support in reporting to you any concerns they have about the serviceability or maintainability of the product, the availability of spare parts, and the usability of the manuals and other information you have provided. 

The choice of whether to purchase or generate electricity and decisions on generator or cable configuration and sparing are often not obvious. An economic study evaluating capital and operating costs and system reliability of several alternatives may be required. 

Having decided the type of generator, the next questions are the capacity and unit sizes. It is usual for the total installed capacity to be capable of meeting the peak demand with spare capacity to meet outages for maintenance. However, consideration can be given to a supply from the electricity supply authority for peak demands and standby. 

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